Historical perspective

Charles J. Tegtmeyer, M.D., is currently Professor of Radiology, Associate Professor of Anatomy, and Director of Angiography, Interventional Radiology and Special Procedures at the University of Virginia Medical Center. Dr. Tegtmeyer has gained recognition as one of the leading proponents of percutaneous transluminal angioplasty and has spearheaded the use of this procedure throughout the vascular tree. Dr. Tegtmeyer attended George Washington University School of Medicine in Washington, D.C., and served residencies in surgery and diagnostic radiology at the University’s hospital. He then pursued a fellowship in cardiovascular radiologv at Harvard University’s Peter Bent Brigham Hospital. Dr. Tegtmeyer has authored over 100 medical articles and presented more than 250 scientific papers and workshops. He serves on numerous editorial boards and professional committees. Dr. Tegtmeyer is the founder and director of the University of Virginia Postgraduate School of Special Procedures for Radiologic Technologists, producer of several medical education films, and the inventor of the Tegtmeyer Lymph Duct Cannulator. He was elected president of the Society of Cardiovascular and Interventional Radiology and is a Fellow of the American College of Radiology. 74

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PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY

HISTORICAL

PERSPECTIVE

Percutaneous transluminal angioplasty (PTA) was first described by Dotter and Judkins in 1964 for the treatment of atherosclerotic peripheral vascular disease.’ It was their observation that during diagnostic angiography, guide wires and catheters could be passed through stenotic, and sometimes even occluded, arterial segments. This led them to develop a percutaneous method for opening narrowed or occluded vessels. Although the technique was successful, it was originally greeted with skepticism in the United States. Most vascular surgeons familiar with atherosclerotic disease considered angioplasty an impossible and dangerous technique. They believed that passing a stiff catheter through an atherosclerotic plaque would shower atherosclerotic debris and result in distal embolization. The technique, however, was exported to Europe where it was refined and widely utilized by Zeitler et al.,’ van Ande1,3 Porstmann,4 Griintzig,5 and others, with considerable success. The original Dotter catheter system utilized a stitf 8-F Teflon catheter inserted over a guide wire. A 12-F catheter was then inserted and telescoped over the 8-F catheter to dilate the artery (Fig 1). The application of the Dotter catheter system was limited by the stiffness of the catheter, the size of the puncture wound, and the potential for distal embolization caused by the forward shearing forces developed by the coaxial system. Staple,’ and later van Andel,3 modified the Dotter catheters by developing a series of graduated 5-F to 12-F catheters with long, gradually tapered tips (see Fig 1). This modification produces more laterally directed compression force and less forward shearing force than the Dotter system. This Cur-r

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design change decreases the risk of distal embolization. These catheters are still used today when firm lesions are encountered and the balloon catheter cannot be advanced through the lesion. Although the Staple-van Andel catheters were an improvement, large vessels still could not be dilated adequately because of the necessity of producing a large puncture wound. Porstmann4 addressed this problem by developing the caged balloon catheter. The instrument consisted of a stiff Teflon catheter with longitudinal slits that could be expanded by a latex balloon. The latex balloon was inserted into the Teflon catheter and inflated. This allowed dilatation of the iliac vessels through a large, but not excessive, puncture wound. The instrument, however, proved very traumatic

FIG 1. Left, a 12-F Dotter over thk 8-F inner van Andel tapered

catheter system. The 12-F catheter to dilate a lesion. dilatation catheter.

catheter Right,

is advanced a 7-F Staple-

76

to

the dilatation site and is no longer used. Then in 1974 Gri.intzig7 revolutionized angioplasty when he developed the soft, flexible, double-lumen balloon catheter. The original balloon catheter had a polyethylene inner catheter with an outer jacket of polyvinyl chloride. The outer layer is molded to form a balloon near the tip of the catheter. The balloon can be inflated to a predetermined diameter in order that the appropriately sized balloon can be selected for each lesion. Because the polyvinyl balloon has limited linear-volume characteristics, it will not overinflate by more than 2-3 mm beyond the designated size. Since the balloon catheter was first introduced, there has been continued improvement. One of the major modifications has been the development of the polyethylene balloon. Compared to the original polyvinyl chloride balloon, this balloon is much stronger and has higher tensile- and yieldstrength characteristics. This helps prevent overdistention of the balloon and possible rupture of the artery. A further improvement has been the development of the new high-pressure balloons, which are even stronger. Because higher pressures can be used and because the balloon has less tendency to assume an hourglass shape, it is possible to dilate lesions that are more resistant. The balloon catheters are available in many sizes. The catheters range in size from 4.3 F to 9 F in diameter, and some balloons can be expanded to 20 mm in diameter. Therefore, they can be inserted through a small puncture wound. Because the balloon catheter applies a lateral compression force instead of a forward shearing force, the risk of distal embolization is greatly reduced. The catheters are flexible, and they can be directed through tortuous vessels and into the branches of the aorta. The aorta and its branches, including the coronary and renal arteries, are now accessible to balloon dilatation. The advantages of angioplasty are both psychological and socioeconomic. PTA is less painful than major surgery and, because it is performed under local anesthesia, avoids the risks of general anesthesia. The procedure can often be performed the same day as diagnostic arteriography, and the hospitalization period is usually only 24 days. These factors dramatically reduce the cost. PTA can be easily repeated if necessary, and future surgical intervention is not precluded. In fact, successful angioplasty saves the saphenous veins for future bypass procedures.

MECHANISM

OF VASCULAR

DILATATION

The mechanism of transluminal angioplasty been a major source of controversy. Dotter 76

has and

Judkinsl originally postulated that the athemmatous material was compressed and remolded by the dilatation catheter. It was believed that the volume of the plaque was reduced by expressing fluid and some of the lipids from the lesion.8 This explanation contributed to the reluctance of physicians to accept the procedure. It was difficult to believe that a firm atherosclerotic plaque could be compressed. Following an early presentation on PTA, one surgeon summed up the feelings of the surgical community when he asked, “Are you trying to tell me that flogging a plaque makes it better?” Experimental studieP4 have helped clarify the mechanism of angioplasty. Atheromatous material is either a solid or a semiliquid, so it is not compressible. It may be possible, however, to redistribute a small portion of the plaque along the vessel wall. If redistribution is a factor, it can only occur in atheromas that have not undergone signiticant fibrotic change. Examination of cadaver and animal models demonstrates that angioplasty produces a controlled injury in the vessel wall. Initially, there is stretching of the vessel wall and desquamation of the endothelium. As the plaque is overstretched by the inflated balloon, the plaque is split and disrupted. Fissures occur in the intima and, with augmented pressure, there is distention and ultimately splitting of the media. The adventitia is stretched beyond its elastic recoil. As soon as the media is freed from the restraints of the atherosclerotic intima, it expands and partially separates from the intima. The vessel remains stretched by the blood pressure and carries the intima and atheromatous plaque with it. As the vessel adapts to the circulatory needs, progressive and further widening of the arterial lumen may occur. This accounts for the continued improvement in vessel diameter demonstrated on follow-up studies of some peripheral lesions after angioplasty. Healing of the disrupted arterial layers occurs with the formation of fibrotic tissue and neointima. This is similar to the healing process that takes place after surgical endarterectomy. There has been some criticism of attempts to extrapolate these experimental results to the clinical setting. Clearly, animal and cadaver models only approximate the atherosclerotic changes seen in living man. The changes produced in the experimental models, however, are also seen in isolated clinical material (Fig 2),15-18 conlirming the theory that controlled injury is the major mechanism of balloon angioplasty. The controlled-injury theory is further substantiated by the appearance of streaks of contrast material seen in the vessel wall” on angiograms obtained immediately after dilatation (Fig 3). Redistribution of the plaque plays a secondary and minor role and only in selected cases. Cum

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FIG 2. Microscopic section of a successfully dilated external iliac artery, removed 3 days after PTA, shows’ a “controlled” injury with fissuring of the intima and atheroma, and partial disruption of the media but with the lumen maintained. (From Wellons HA, Tegtmeyer CJ, Crosby IK: Balloon catheterization of the iliac artery: Results in 34 patients. Va Med 1981; 108589-602. Reproduced by permission.)

Nonatherosclerotic lesions can also be dilated by PTA.2~26 The mechanism is similar to dilatation of atherosclerotic lesions whereby the intima is disrupted, the lesions are stretched, and fibrotic bands are disrupted. Since its introduction, the technique has been refined and simplified. Because the procedure produces a controlled injury, it is far from innocuous. VTA should be performed only by experienced angiographers. Inflating the balloon is simple, but successfully crossing a tight stenosis with a catheter and a guide wire requires skill. Selection of the proper-sized balloon catheter requires experience, and the proper selection of patients for angioplasty is mandatory. These factors are very important if good results are to be obtained. EQUIPMENT

Dilatation

Catheters

There are two types of dilatation catheters widely used today-the long, tapered Teflon Staple-van Andel catheters and the balloon catheters. The Staple-van Andel catheters (see Fig 1) are available in 5-F to 12-F sizes. When resistant lesions are encountered, these catheters are used to initiate the dilatation procedure. If the balloon catheter cannot be advanced across a firm lesion, a Staple-van Andel catheter can be advanced, partially dilating the lesion. The balloon catheter can then be advanced through the lesion. If the tapered catheter is used as the sole dilatation catheter, the results are not as good as those achieved with a balloon catheter. A 9-F Staple-van Andel catheter is equal to a 3-mm balloon catheter. A 12-F catheter will dilate a 4-mm vessel; however, the puncture site is also dilated up to 12 F. Cum

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The Grtintzig balloon catheters are utilized for most dilatation procedures. There are two basic types of balloon catheters-the coaxial catheters and the single double-lumen balloon catheters. The coaxial catheters (Fig 4) are used to dilate the coronary arteries and, in special situations, very tight renal artery stenoses that cannot be passed by other techniques, or in the treatment of distal or branch stenoses. The coaxial catheters utilize an 8-F or 9-F guiding catheter and usually a small 4.3-F or 4.5-F balloon catheter that is inserted through the guiding catheter. There are some 2.9-F balloons available for specialized situations. The flexible single double-lumen balloon catheters are used to dilate most lesions. These catheters are flexible, but they differ somewhat depending on the manufacturer. These balloon catheters are available in balloon sizes of 2-20 mm, and the catheter shafts range from 4.3 F to 9 F. There are two basic types of balloon cathetersthe polyethylene balloons (Meditech, Watertown, Mass.; IJSCI, Billerica, Mass.; Cook, Inc., Bloomington, Ind.) (Fig 51 and the Mylar (high-pressure) balloons (Meditech, USC11 (Fig 61. The polyethylene balloon catheters are used in most situations. They are more flexible, and this is an advantage when one is maneuvering around corners such as over the aortic bifurcation or into the renal arteries. The balloons also have a lower profile, so they can be passed across tight lesions easier than the high-pressure balloons. An Et-mm balloon, however, will rupture at a pressure slightly in excess of 4 atm. If more force is needed to dilate the lesion, a high-pressure balloon is necessary. These balloons will take up to 20 atm of pressure. A major drawback of the Mylar balloons is the abrupt transition between the balloon and the catheter. This makes it more difficult to insert the balloon 77

FIG i 3. Exa w le of subintimal

contrast after angioplasty in a 63-year-old pati’ ent VI/ho underwent PTA followed by a femoropopliteal bypass. showing a tight stenosis (arrow) in the proxi4 F)elv ic ari ieriogram mal ext ei rnal I iliac artery. Peak-to-peak systolic gradient was 15 mm showing a-mm balloon in place. 4. B, oo- mm spot radiograph

78

C, immediately after PTA, subintimal contrast mate trial is seen at the angioplasty site. A 2 mm Hg gradient remains. 0, I,el vie arteriogram obtained 2 years after the procedure sho\n 1s a wit 3ely patent vessel (arrow).

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FIG 4. Coaxial balloon catheter system. The 4.3-F balloon has been advanced out of the 8-F renal guiding catheter. A O.OlCinch platinum-tipped steerable guide wire is seen protruding from the balloon catheter.

through the puncture site and to pass the balloon across the lesion. Another disadvantage of the Mylar balloons is that they are not available with the working portion of the balloon close to the tip of the catheter. This is a disadvantage when dilating lesions in close proximity to a bifurcation of a vessel such as in the renal artery and distal popliteal arten/. However, it is hoped that high-pressure balloons with the working portion of- the balloon close to the tip will soon be available.

FIG 5. Polyethylene GrOntzig-type balloons. Left, a 6-mm-diameter, long balloon catheter on a 7-F shaft. Right, an 8-mm-diameter, cm-long balloon catheter on an 8-F shaft. Cum

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2-cm3-

FIG 6. High-pressure GrDntzig-type balloons. balloon (Meditech, Watertown, Mass.). balloon (USCI, Billerica, Mass.).

Let?, an 8-mm Right, an 8-mm

Blue Max PE PLUS

Guide Wires Most diagnostic catheters are tapered over 0.038inch guide wires. However, the 7-F balloon catheters take either a 0.035~inch or a 0.038-inch guide wire. The miniballoons take smaller wires, ranging from 0.014 to 0.028 inch. It is essential that an intraluminal course be maintained when crossing the lesion. It is also very important to cross the lesion as atraumatically as possible. To accomplish these goals, a variety of Teflon-coated guide wires are necessary. Begin with flexible guide wires and progress to stiffer wires only when necessary. The lesion is approached with a heavy-duty, movablecore 1.5~mm J wire or a long tapered 1.5-mm J wire. The catheter is then advanced until it is 2-3 cm proximal to the lesion. If the J guide wire can be advanced through the lesion without resistance, it is used to cross the lesion. In most very tight lesions, however, resistance is encountered, and it is best to cross the lesion with a straight guide wire. A long, tapered straight guide wire or a Bentson wire will cross most lesions. If the lesion is tortuous and irregular, a 0.014- or 0.018~inch platinum-tipped steerable guide wire can be used. The soft tip on these wires protects the artery from damage. If these guide wires will not cross the lesion, a movable-core tight J wire is utilized with the core fully inserted, making this a very firm straight wire. The advantage of the wire is that once the lesion has been crossed, the core can be 79

withdrawn and the J will reform if the guide wire is within the lumen. The wire will maintain a straight configuration if it is subintimal. Once the diagnostic catheter has crossed the lesion, the catheter must be exchanged for the appropriate dilatation catheter. It is important to avoid trauma to the vessel distal to the lesion during the exchange. Despite precautions, the tip of the guide wire moves in the vessel during the exchange. It is important, therefore, to use a wire that is stiif enough throughout most of its length to assist the balloon catheter in passing through the lesion, but flexible at the tip. There are two basic exchange J wires-a 0.035inch, heavy-duty, 2-3 movable-core 1.5~mm J with the core withdrawn cm, and a 0.035~inch 1.5-mm J Rosen wire?’ It is important that the diameter of the J be smaller than the vessel in which it is placed. If the vessel is too small, a straight exchange wire should be used. After the balloon catheter has been inserted, a Y adapter (Fig 7) is attached to the catheter. A 0.025inch 1.5mm J guide wire is inserted through the catheter. This allows the guide wire to remain in place across the lesion during the procedure, and the balloon can be readvanced across the lesion without the concern of going subintimally. Contrast material can be injected through the Y adapter, and pressures can be obtained with the guide wire still in place.

Diagnostic

Catheters

A wide variety of diagnostic catheters are available, and multiple shapes are needed in special circumstances. The key to crossing the lesion is using the proper-shaped catheter, and this selection must be individualized in each situation.

The Tuohy Borst or Y adapter is shown with the 0.025inch guide wire in place and the side arm attached to a connecting tube. Contrast material can be injected and pressures obtained with the guide wire in place. so

There are two basic approaches for crossing the lesions. Straight catheters can be used in combination with a series of cmved guide wires, or the catheter can be shaped and flexible straight wires with either a tight J or straight tip can be utilized. Often a combination of these approaches is necessary. A 5-F Tegtmeyer catheter (Cook, Inc., Bloomington, Ind.1 (Fig 8) is an ideal basic catheter for angioplasty. In the extremities, the tip can be straightened when necessary, and the slight 150' bend in the tip is ideal for negotiating tortuous vessels. The 5-F catheter is flexible, making it relatively atraumatic. Yet the catheter can be stiffened, when necessary, because the catheter takes a 0.035~inch guide wire. When the contralateral approach is used for iliac lesions, a cobra or a sidewinder catheter is used to cross the aortic bifurcation. In most cases a 5-F diagnostic catheter is preferred. The catheters still retain some torque control which is necessary to cross the lesions, yet they are small enough to be passed across tight stenoses. Larger diameter catheters select the vessels more easily. However, they are difficult to pass across tight stenoses and may be more injurious to the walls of atherosclerotic vessels. INFLATING

THE

BALLOON

CATHETER

The angioplasty balloon catheters are inflated with a mixture of one-half contrast material and one-half saline. This mixture has a concentration of 30%. It is dense enough to opacify the balloon, yet fluid enough to inflate or deflate the balloon rapidly. The catheters can be inflated either with an automatic pump or by hand. The pump, which uses COz, is available iiom USC1 WSCI, Billerica, Mass.). The advantages of the pump include re-

FIG 8. The Tegtmeyer catheter is a 5-F soft catheter with a 150” bend in the tip (Cook, Inc., Bloomington, Ind.). The catheter takes a 0.035inch wire and is a good basic catheter for angioplasty. Curr

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mote control, which permits the angioplaster to have both hands available to stabilize the balloon position during inflation, rapid inflation and deflation of the balloon, easy inflation to a predetermined level, ease in maintaining a constant pressure, and complete deflation when the balloon is emptied. The disadvantage of the pump is the cost. Many angiographers prefer to use only a syringe because of simplicity and cost. There are several basic physical principles that guide the choice of the syringe. If a constant force is applied on the plunger, the pressure is inversely proportional to the syringe diameter. The smaller the diameter of the syringe, the greater the pressure that can be applied. Inflation of the balloon should always be monitored with a pressure gauge. Initially, when angioplasty was performed with polyvinyl chloride balloons, a few angiographers suggested that they did not need a pressure gauge because they could monitor, by feel, the amount of pressure being applied. While this was true with the polyvinyl chloride balloons, it is not true with the polyethylene balloons. If a pressure gauge is not utilized with the new balloons, it is impossible to know how much pressure is being applied. The best pressure gauges (Fig 9) are constructed so that contrast does not enter the pressure chamber. The gauge should also be easy to clean because if contrast material crystallizes in the gauge, it is ruined. Also, if small crystals of contrast material are injected into the balloon, the small lumen of the balloon

may be occluded, making it impossible to deflate the balloon. A 3-ml syringe with an inner diameter of 0.78 cm can generate 21 atm of pressure. A loml syringe with a barrel diameter of 1.4 cm is capable of generating only 9.4 atm of press~re.~~ When the syringe is deflated, the reverse is true. The larger the syringe, the greater the suction produced. Some angiographers utilize a two-way stopcock and inflate with a small syringe and deflate with a larger syringe. However, a lo-ml syringe is the ideal size, if only one syringe is employed. This syringe minimizes the likelihood of overinflation of the balloon, and at the same time provides enough pressure to easily inflate the balloon to 6 atm. There are several general principles to be considered when choosing and inflating the balloon. The balloon will provide a controllable, nearly pure radial force. This radial force reduces the chance of distal embolization because there is no axial component once the balloon is in place. The artery to be dilated and the balloon catheter may be considered as thin-walled, somewhat elastic cylinders. Thus, balloon dilatation is governed by the law of Laplace (T = P X R).28 The law of Laplace states that wall tension CT) in a cylinder is equal to its internal pressure (PI multiplied by its internal radius (RI. Therefore, increasing the radius of the balloon increases the tension on the lesion. If the balloon is undersized, very little force will be applied to the lesion no matter how much pressure is applied to the balloon. Selection of the proper-

FIG 9. Pressure inflation i pressure angioplasty Billerica, F connected (Meditech,

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gauges for monitoring the pressure of the balloons. Left, gauge attached to an inflation syringe (USCI, Mass.). Right, pressure gauge to a LeVeen inflator Watertown, Mass.).

81

sized balloon is critical. Several manufacturers are currently developing catheters and guide wires with distance markers that can serve to provide an approximate magnification correction factor for vessels and balloon sizing. This is especially important when only digital subtraction diagnostic angiography images are available. The vessel is measured proximal and distal to the stenosis, and the original size of the vessel is estimated in the area of the stenosis (Fig 10). If the artery is estimated as 8 mm in diameter, this is the size of balloon that is employed. This does not take into account the magnification factor, so the artery is slightly overdilated. When in doubt, use the smaller-sized balloon. The amount of pain experienced by the patient can indicate whether the proper-sized balloon has been used in the iliac or renal arteries. Patients may normally experience mild to moderate pain during inflation of the balloon. The pain, however, should diminish almost immediately after deflation of the balloon and disappear, usually within a minute. Continued intense pain after balloon deflation is frequently an indication of severe arterial injury, such as rupture or occlusion. If the patient experiences unusually severe pain during balloon inflation, it is prudent to deflate the balloon immediately, as a test. If the pain disappears, it is probably safe to use the next size smaller balloon. Proceed with caution, however, because severe pain during inflation of the balloon indicates that the balloon is probably too large. Inversely, if the patient does not feel any discomfort when the bal-

loon is inflated and the indentation of the plaque on the balloon remains, or if during deflation the balloon is reindented in the region of the lesion, or a test injection shows a residual stenosis, a larger balloon is then inserted to redilate the lesion (Fig 11). This is done because follow-up studies have shown that if a greater than 30% residual stenosis is left behind, the lesion is more likely to recur.29-31 Once the proper-sized balloon has been selected, the pressure in the balloon becomes a factor. For a given-sized balloon, an increase in pressure will increase the dilating force in a linear fashion, providing there is no change in the lesion. Most atheromatous lesions are thick-walled, so the law of Laplace provides only an approximation. However, the stress on the wall increases as the diameter of vessel increases and the wall thickness decreases. When the lesion is dilated, the risk of vessel rupture increases as larger balloons are employed and when more pressure is applied. It is also important to remember that normal vessels will rupture at a lower pressure than thickened atheromatous vessels. This factor should be kept in mind when choosing the length of the balloon. For the same pressure, the balloon will exert more pressure on a large lesion than a small one. At the same pressure, a balloon will exert more force on a tight stenosis than on one that is not as severe. Maintenance of high pressure over a longer period of time weakens the lesion somewhat, resulting in further dilatation of resistant lesions. Also, repeated dilatations will stretch the wall of

FIG 10. Selecting the proper-sized angioplasty balloon. The angioplasty balloon is selected to correspond to the original diameter of the stenotic vessels, as depicted on the angiographic films. Since the

vessels are magnified by 15%-20% on standard angiograms, the arteries will be overdilated by approximately 1 mm in the peripheral vessels and slightly more in the iliac vessels.

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FIG 11. Arteriograms of a 59-year-old hypertensive man with progressive renal failure exacerbated by captopril therapy illustrate the importance of selecting the proper-sized balloon. A, midstream arteriogram reveals a tight stenosis (arrow) in the left renal artery. B, arteriogram obtained immediately after dilatation with a 7-mm balloon shows a large subintimal split; however, there is residual stenosis (arrow). The patient did not experience any pain when the balloon was inflated. C, lesion was immediately redilated with an 8-mm balloon, and the vessel is markedly improved (arrow). Comment: The initial balloon was chosen by measuring the artery, as described in the text. This technique is usually successful; however, the lesion was underdilated. In this case a larger balloon was necessary. (From Tegtmeyer CJ, SOS TA: The techniques of renal angioplasty. Radiology 1986; 161577586. Reproduced by permission.)

the vessel and the balloon somewhat, increasing the diameter of the vessel in resistant lesions. The same physical factors that govern the success of the dilatation also affect the performance of the balloon. The more pressure applied to the balloon, the longer the pressure is applied, and the more times the balloon is inflated, the more likely it is that the balloon will rupture. The larger the diameter of the balloon, the less pressure it takes to rupture the balloon. An S-mm balloon will rupture at less pressure than a 4-mm balloon. The higher tensile- and yield-strength of polyethylene as compared to standard polyvinyl chloride provides a wider margin of safety. Polyethylene balloons are much stronger and rupture at higher pressures than polyvinyl chloride balloons, and the new Mylar (high-pressure) balloons have an even greater margin of safety. If a high-pressure balloon is used to dilate a resistant lesion, a guide wire should always be in place during the dilatation, and the balloon should be inflated slowly just to 2 atm. Then the pressure is increased slowly. This is because the high-pressure balloons, when fully inflated, become so rigid that the tip of the balloon may be driven into or through the wall of the artery. Also, the split in the vessel wall may be too extensive if the balloon is Curr

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inflated rapidly. Gradual inflation will usually prevent extensive damage to the vessel. Given all these factors, balloon dilatation should be approached cautiously. The size of the balloon is critical. Employ only enough force to adequately dilate the lesion. Begin with 2 or 3 atm of pressure. At these low pressures, the impression of the lesion on the balloon allows proper positioning of the balloon. Once the balloon has been properly positioned, increase the pressure until the balloon expands completely. Never move the balloon while it is inflated. Moving the inflated balloon converts the radial force into an axial shearing force and may result in complete disruption of the intima and distal embolization. Usually 4-10 atm of pressure is adequate to dilate most lesions. Inflate the balloon for 30-60 seconds, then deflate it. Observe the balloon fluoroscopically during deflation because at reduced pressure and volume, the balloon forms a cast of the artery, and reindentation in the area of the lesion suggests an incomplete dilatation. The number of repeat dilatations should be kept to a minimum to avoid increased trauma to the vessel and to prevent distal embolization. In most cases, two to three dilatations are adequate. If the lesion does not respond, increase the p~mssure and the duration of the inflation. The 83

inflation of the balloon should always be monitored under fluoroscopic control and a pressure gauge should be used. Remember only polyvinyl chloride balloons change shape with increased pressure, either “ballooning” eccentrically or lengthening. These are signs of impending rupture, and the balloon should be rapidly deflated and not reinflated. Do not exceed 6 atm when using regular polyethylene balloons larger than 6 mm in diameter. Some lesions will not respond completely, but remember that excellent is the enemy of good. In an effort to achieve an excellent result, the artery or the balloon may be ruptured, resulting in a major comnPR4 plication. Poiseuille’s equation (Q = 8’1) reveals that doubling the radius of the vessel produces a 16-fold increase in flow. Therefore, there may be dramatic improvement in flow despite the appearance of the lesion. If a large residual stenosis is left behind, however, the lesion is more likely to recur.2s31 This, obviously, is preferable to rupturing the vessel. Angioplasty produces an injury in the vessel wall, and it is important to keep the injury under control. The easiest way to rupture the vessel is to employ an oversized balloon.

HEMODYhNMIC

MEASUREMENTS

It is very important to realize that single-plane arteriography often underestimates the degree of arterial obstruction present. This is because atherosclerotic plaques often begin in the posterior wall of the vessel and can be very extensive before they are appreciated in the anteroposterior view. Biplane and oblique views are very helpful, especially in aortic and pelvic disease; however, arteriography alone cannot assess the hemodynamic significance of the lesion. Complete occlusion of a large or medium-sized artery may not produce symptoms even with exercise. The degree to which a stenosis produces symptoms is dependent on the location and extent of the disease. The success of angioplasty is directly dependent on ameliorating the patient’s symptoms, not on correcting asymptomatic stenoses, no matter how beautiful the result. To achieve good results, it is necessary to understand the principles controlling flow in a vessel. Blood flows from an area of high pressure to areas of lower pressure. In normal individuals, there is only a 10 mm Hg gradient down to the level of the arterioles. Across the arterioles, the pressure drop is much greater. Peripheral vascular resistance is controlled by vessels 200 l.~and smaller. 84

The flow in the blood vessels is governed seuille’s law:

Q=

by Poi-

m P R4

81?L where Q = flow, R = radius of the vessel, P = pressure drop across the segment, q = viscosity of blood, and L = length of the vessel.

In most situations, the viscosity can be considered constant, so the principal determinants are the length and radius of the vessel. Because the radius is raised to the fourth power, this is the major factor governing the flow across the lesion. The velocity of the blood flow is also important in determining the magnitude of the pressure gradient. The velocity of the blood is increased through the stenosis, and the pressure is decreased in the area of the stenosis. Once the stenosis is dilated, the velocity decreases and the pressure increases. This pressure increase is what keeps the dilated segment open and results in the continued improvement sometimes seen in the vessel following dilatation (Fig 12). Flow is directly proportional to the cross-sectional area of the vessel and inversely proportional to the peripheral vascular resistance. Flow is decreased when a stenosis increases beyond the critical point (approximately 80% of the cross-sectional area and 50% of the vessel diameter). Under certain circumstances, a decrease in the peripheral vascular resistance by the arterioles distal to the occlusion may be sufficient to compensate and maintain flow at a resting level. However, after exercise the peripheral vascular resistance falls because of increased metabolic demand, and this increases the pressure gradient, resulting in symptoms. This is the basis for challenging the patient by reducing the peripheral vascular resistance by drugs or by exercise in patients with questionable lesions. Pressure measurements provide a more precise determination of the significance of the lesion than arteriography.32 Pressures of the aorta and the iliac vessels should be obtained before and after dilatation. Ideally, two catheters should be employed, one proximal to the stenosis and one distal to the stenosis, and if possible the pressures should be obtained simultaneously. This is practical in the iliac vessels because the aortic catheter can be inserted on the contralateral side, and the other catheter can be placed in the ipsilateral femoral artery distal to the obstruction. If two catheters cannot be inserted, a pull-back pressure can be obtained across the lesion. This Cur-r Probl

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Psys 112mm Hg.

Psys 212mm

Hg.

AFTER

Psys l2Omm

Hg

FIG 12. Resolution of a residual stenosis as seen on follow-up studies. A complete block in the right common iliac artery was dilated in a 5.5year-old, frail, diabetic woman. Occasionally long blocks in the iliac arteries can be dilated if the clinical situation Psys 170mm Hg Psya 164mm Hg warrants. A, pelvic arteriography reveals a 4.7~cm-long complete block in the right common iliac artery. There is a systolic gradient of 92 mm Hg across the lesion. B, the balloon in place. C, follow-up arteriogram obtained immediately after PTA demonstrates a patent artery; however, there is a residual stenosis 3 MON THS (arrow). The gradient has been reduced to 18 mm Hg. D, plethysmography and Doppler ultrasound pressure recordings obtained at the ankles show continued improvement after the procedure, both immediately after, and at 1 week. The pulse Psys 180mm Hg Psys 190mm Hg. waveforms and pressures in the right ankle returned to normal at 3 months. Recordings from the left ankle are shown for comparison, E, follow-up arteriogram obtained 4% months after PTA shows complete resolution of the residual stenosis. (From Tegtmeyer CJ, Moore TS, Chandler JG, et al: Percutaneous transluminal dilatation of a complete block in the right iliac artery. AJR 1979; 133532-535. Reproduced by permission.) 1 WEEK

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86

should be performed with a 5-F catheter which takes a 0.038~inch wire. The catheter should be advanced through the stenosis, and a 0.025inch wire should be inserted through the catheter and up to the level of the descending thoracic aorta. Using a Y-adapter, the pressures can be obtained as the catheter is pulled back across the stenosis. The peak systolic pressure is recorded, and the peakto-peak systolic gradient can be calculated. The catheter is then easily advanced over the wire and back into the abdominal aorta above the stenosis. This same technique can be utilized after dilatation to assess the results. In surgery, there is an old adage, “never give up an advantage.” Once the stenosis has been crossed, do not pull the catheter back without leaving the wire across the lesion. What was simple the first time may be difficult, if not impossible, the second time. A peak-to-peak systolic gradient of lo-15 mm Hg or greater at rest is considered significant (see Fig l&AA). If a gradient of less than 10 mm Hg is recorded, blood flow augmentation can be performed. The peripheral vascular resistance can be decreased by exercise, ischemic reactive hyperemia, or drugs. Blood pressure cuffs can be applied to the thighs and inflated to above the systolic pressure for 3-5 minutes to cause distal ischemia. Tolazoline (Priscoline) produces peripheral vasodilation. This is the easiest technique to alter blood flow: 25 mg of tolazoline in 10 ml of normal saline is injected intraarterially distal to the stenosis, and the pressure distal to the stenosis is monitored. Papaverine (30 mg) can also be utilized. A lesion is considered hemodynamically significant if the peak systolic pressure decreases by 15% or more. Direct pressure measurements are more difficult to obtain in smaller vessels, because when the catheter is across the stenosis the pressure is artificially dampened. This is because the catheter occupies a significant percentage of the total crosssectional area of the vessel. Following angioplasty, however, a pull-back tracing showing no gradient is significant.

PLETHYSMOGRAPHIC AND DOPPLER uLTRA!3ouND sTuDIEs Noninvasive hemodynamic studies are essential in the evaluation of vascular lesions of the extremities. They provide a quantitative assessment of the extent and hemodynamic effects of vascular disease prior to intervention. Following angioplasty, they are necessary to quantify the results of the procedure (see Fig 12,D). A variety of techniques and devices are available for measuring systolic pressures, the simplest of 86

which is the ultrasonic velocity detector. The Doppler device transmits high-frequency sound waves into the body. These sound waves are altered in frequency by the moving blood cells in an amount proportional to the velocity of flow. The Doppler device can be used to detect flow in the vessels of the extremities. Segmental pressures can also be obtained in the extremities by placing a pneumatic cuff proximal to the vessel being evaluated. Once the arterial velocity signal is located, the cuff is inflated above the systolic pressure and gradually deflated until the Doppler signal is detected. The point at which the flow is first heard is the systolic pressure at that level in the extremity. Pressures can be detected in the thigh, calf, ankles, toes, and brachial vessels. The brachial artery pressure is compared to the ankle pressure, yielding the arm/ankle index. The ankle pressure is almost always equal to or greater than the brachial pressure in normal individuals, so normally the arm/ankle index is less than or equal to 1. Patients with claudication usually have an ankle pressure 50%~80% of arm pressure. In patients with rest pain, the ankle pressure is less than 50% of the arm press~re.~~ In some patients, exercise or reactive hyperemia is necessary to produce an abnormal pressure. This technique can also be utilized to localize the disease. Lower thigh pressures indicate aortoiliac, common femoral, or combined superficial femoral and profunda femoral disease. A gradient of more than 20 mm Hg between the thigh and calf pressure implies distal superficial femoral or popliteal disease. A gradient of more than 20 mm Hg between below-knee and ankle cuffs is evidence of tibial and peroneal disease. This technique has certain limitations. Artificially elevated thigh pressures are measured if narrow cuffs are used, and in very large individuals. Factitiously high pressures are recorded in calcified arteries that are difficult to compress. This is seen most often in diabetics and patients with severe renal disease. Pulse-volume recordings are also very helpful for evaluating the hemodynamics in the extremities. Pulse-volume recordings are segmental plethysmographs that measure and record on graph paper variations in arterial volume during each cardiac cycle. Interpretation of the waveforms permits evaluation of the effects and extent of peripheral vascular disease. When the plethysmographic waveforms are combined with the Doppler pressures, an accurate evaluation of the hemodynamics of blood flow in the extremities can be obtained. A baseline study should be performed prior to angioplasty. Recordings can also be obtained during the procedure to monitor the progress of the Curr

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angioplasty procedure. Repeat studies should be obtained 24-48 hours after the procedure. Improvement in the waveforms and in the arm/ankle index is indicative of a positive result following angioplasty.34 The studies should be repeated every 3 months for the first 6 months, and every 6 months thereafter. If the studies show a decrease in the hemodynamics, a repeat angiogram is indicated to look for a recurrence of the lesion or progression of the disease.

an patients with single-segment disease, correction of the lesion should restore normal blood flow. The patient should be asymptomatic, and the ankle pressure should be greater than or equal to the arm pressure. Exercise should not cause the ankle pressure to fall. If the patient has multisegment disease and only the proximal obstructions are corrected, the distal pressures will increase, but they will not be normal. Walking time will increase, but the pressure will still fall after exercise.

PATIENT

INDICATIONS EXTRIXMITIES

EVALUATION

The patient with atherosclerosis needs a complete evaluation. Atherosclerosis is a diffuse, progressive disease. Most patients with arterial occlusive disease of the lower legs die of coronary or cerebral complications of the disease, not from lesions in the extremities. The absence of pulses in the asymptomatic patient is not an indication for correction of the lesion. If the patient is symptomatic, to what extent is he or she disabled? Minor symptoms can often be ameliorated with an exercise program, and with control or elimination of risk factors such as smoking, diabetes, congestive heart failure, and the elimination of certain drugs that precipitate claudication, such as Inderal. The patient with mild to moderate intermittent claudication is likely to have single-segment disease. The appearance of the feet is useful only if changes indicative of advanced disease are present. Most patients with single-segment disease will exhibit only dependent rubor. Pain on ambulation is not always due to vascular insufficiency. Thrombophlebitis, arthritis, and sciatica may also simulate intermittent claudication. Rest pain is due to a marked reduction in perfusion. These patients have more severe disease, and the ankle pressure is usually less than 40 mm Hg. With far-advanced disease, it is not uncommon to find an absence of Doppler signals in the feet. This is an ominous finding, as is the presence of gangrene. Patients with associated diabetes, hypertension, and/or hyperlipidemia have a poorer prognosis. The clinical examination and noninvasive pressure measurements provide useful functional data; however, if the functional disability warrants correction of the disability, an arteriogram is necessary for complete visualization of the vascular tree. Good arteriography is especially important prior to angioplasty. It is essential to delineate the exact location and extent of the vascular disease. Further, if angioplasty is contemplated, the vascular access to the lesion and the location of the collateral vessels must also ‘be ascertained. It is important to remember, however, that single-plane arteriography often underestimates the severity of the disease present. Curr

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FOR ANGIOPLASTY

IN THE

PTA has been utilized most frequently to treat ischemic vascular disease of the extremities. Selection of the correct therapy for the patient should be visualized and based on consultation among the patient, the primary physician, the vascular surgeon, and the angiographer. Choosing the most appropriate therapy involves a combination of clinical and angiographic findings. Angioplasty is indicated only in patients who are symptomatic. The .demonstration of an arterial stenosis on a diagnostic arteriogram is not an indication for angioplasty. The use of prophylactic angioplasty in the extremities is to be discouraged. Because percutaneous transluminal dilatation causes a controlled injury to the vessel wall, it is not considered a prophylactic procedure. Although serious complications requiring surgical intervention are rare, PIA should not be undertaken without considerable thought in patients who could not withstand surgery if a complication were to occur. The clinical indications for balloon angioplasty are similar to those for surgical intervention in the extremities. Angioplasty should be considered in the following clinical situations: 0 The presence of intermittent claudication when the patient’s life-style is adversely affected by the symptoms. 0 The presence of rest pain. 0 The presence of ischemic ulceration or when poor wound healing is evident following a surgical procedure. 0 The presence of impending gangrene or overt gangrenous changes. Angioplasty is often employed to complement surgical procedures. Angioplasty is helpful as an adjunct to surgery in the following situations: l Correction of an iliac lesion to ensure good inflow prior to femoropopliteal bypass. 0 Correction of an iliac lesion to ensure good inflow prior to a femorofemoral crossover graft when one iliac vessel is completely oc_ eluded. 0 When amputation is contemplated, angio87

plasty may be performed prior to amputation in an attempt to salvage the limb by increasing the inflow. (PTA may also be done to decrease the level of the amputation). 0 Correction of postoperative strictures in patients with anastomotic stenoses in bypass gI%lftS.

0 Correction of stenoses in the native vessels when symptoms are present and the graft is threatened after bypass surgery. Angioplasty is sandwiched around surgery in the treatment of vascular disease. Angioplasty is indicated as an alternative to surgery in symptomatic patients with short, isolated stenoses. It is generally not indicated in patients with diffuse disease unless surgery is contraindicated because of age or severe anesthetic risk due to coronary, cerebral, or renal disease. It is also indicated in symptomatic patients who have a short life expectancy and in those who are morbidly obese. Anatomic

Indications

Proper patient selection is one of the most critical aspects of successful angioplasty. Patients who are ideally suited for angioplasty are the following: 0 Aorta: short focal stenoses. l Aortic bifurcation: short stenoses involving the aortic bifurcation. 0 Iliac arteries: stenoses, unless very extensive; and occlusions, only if short and the vessel is straight. 0 Common femoral arteries: stenoses and ocelusions . 0 Superftcial femoral arteries: single stenosis; multiple stenoses, unless extensive; and occlusions less than 10 cm long. 0 Popliteal arteries: stenoses and occlusions, with best results obtained in short lesions. When these lesions are dilated, a high initial success rate will be achieved, and good long-term results will be attained. Certain other lesions are amenable to balloon dilatation if the clinical situation is warranted: l Patients with several focal stenoses in the iliac vessels. 0 Patients with lesions at the aortic bifurcation and focal stenoses in the iliac vessels. 0 Patients with short, isolated occlusions (< 2 cm) of the iliac vessels, but only if the vessels are relatively straight. 0 Vessels below the trifurcation: stenosis, best results obtained in short lesions; angiographer needs extensive experience. If the angiographer is experienced, good results will also be achieved in these lesions. Patients with diffuse multiple stenoses of the iliac or distal vessels are likely to have a better longss

. term result after surgical bypass. These lesions, however, may respond to angioplasty if the patient is not a good surgical candidate. As in the case of surgery, the long-term results will not be as favorable in patients with poor distal runoff. The longterm results are affected by the severity of the disease. Patients with multiple stenoses and diffuse disease will not achieve as good a long-term response as those with isolated disease. The best results can be anticipated in persons with isolated stenoses. Contraindications The contraindications, like the indications, are relative and depend on the clinical situation and the anatomy. There are certain situations, however, when PTA cannot be depended on to produce consistently good results: 0 Patients with ulcerated plaques in the aorta or iliac vessels and with blue-toe syndrome. l Patients with aneurysms and stenoses of the vessels. 0 Patients with embolic occlusion. 0 Patients with long complete blocks in the iliac vessels. 0 Patients with recent complete occlusion of the vessels. 0 Patients who have a major artery that takes its origin at the level of the proposed dilatation. Patients with ulcerated plaques and the clinical manifestations of blue-toe syndrome are not candidates for angioplasty. PTA is likely to precipitate embolism at the time of the procedure, and dilatation of the lesion will not solve the problem of recurrent emboli. This needs to be treated surgically in order to bypass and isolate the lesion. Patients with long chronic occlusions in the iliac vessels may be treated by angioplasfl if the vessel is perfectly straight and the clinical situation warrants. These lesions, however, are more prone to distal embolization than iliac stenoses. Recent complete occlusions are often due to fresh thrombus formation superimposed on a preexisting stenosis. In this situation, an attempt to dilate the lesion may result in distal embolization. Recent thrombus does not respond to dilatation. Recent occlusions may be given a trial with thrombolytic therapy if the clinical situation is warranted. If the thrombus lyses, the underlying lesion can be treated with angioplasty. If a major vessel takes its origin in the middle of the stenosis, the lesion should be approached with caution. When the clinical situation necessitates balloon dilatation, either the lesion should be underdilated or two guide wires should be utilized. One wire should be placed in the branch Curr

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vessel and the other through the lesion. If the balloon procedure compromises the branching vessel, a balloon can then be placed in the branching vessel to correct the problem. In the past, extensive calcification of the lesion, eccentric location of the stenosis, multiple lesions, and stenoses at the bifurcation of the aorta were listed as contraindications. The evolution of angioplasty techniques and the development of new balloon catheters have changed the indications for angioplasty, and these lesions can now be treated with PTA. With the new high-pressure balloon catheters that are available, extensively calcified lesions can be dilated if the lesion can be crossed with the guide wire and catheter. Eccentric lesions can also be treated with the balloon catheter and good results can be obtained. Now that stronger, less compliant, longer balloons are available, multiple stenoses and lesions greater than 2 cm can also be dilated. Balloons that are 8 cm can be used to dilate these lesions and good results are usually obtained. Lesions at the bifurcation of the abdominal aorta involving the aorta and common iliac vessels can also be dilated by using the “kissing balloon” technique.368 37 The proper treatment of peripheral vascular disease requires a team approach. Selection of the correct therapy for the patient should be individualized and decided after consultation with the patient, the primary physician, the vascular surgeon, and the angiographer. Choosing the most appropriate therapy entails reviewing the clinical and angiographic findings. The risks and benefits of all the options should be explained to the patient . ANGIOGRAPHIC

EVALUATION

Once a clinical decision has been made to treat the patient, a diagnostic angiogram is necessary before a final decision concerning the best course of therapy can be made. At the University of Virginia, all patients scheduled for peripheral arteriography are considered potential candidates for angioplasty. The evening prior to angiography, the patient’s chart is read, and the patient is examined by an angiographer who explains the angiogram and the possible balloon procedure, including the risks and benefits of both the arteriogram and the balloon angioplasty procedure. The patient is told that an arteriogram will be obtained and that the angiographer, along with the surgeon, will review the films and decide the best therapy, which will then be discussed with the patient prior to proceeding. Informed consent is obtained for both the arteriogram and the possible balloon angioplasty procedure. The patient is placed on clear liquids after midnight. An intravenous (IV) line is inserted Cut-r

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prior to the arteriogram. The patient is given 10 mg of Valium orally and 0.4 mg of atropine intramuscularly (IM) on call to the angiographic suite. Because of the diffuse nature of the atherosclerotic process, a complete angiographic workup, including an abdominal aortogram and a runoff study, is needed to fully evaluate the patient. The vessels should be completely visualized from the take-off of the renal vessels to the distal calf. Lesions in the aorta and iliac arteries are often eccentric and posterior in location. Their significance is underestimated on single-plane angiograms. Therefore, it is frequently necessary to obtain oblique views of the iliac vessels and lateral films of the aorta to completely evaluate lesions in these vessels. High-quality angiography is necessary because the exact nature of the lesion must be delineated before a decision can be made regarding the feasibility of balloon angioplasty. A major reason for failure of angioplasty is failure to accurately define the anatomy of the lesion before attempting the procedure.

TECHNIQUE Retrograde

Puncture

At the University of Virginia most angioplasties are performed at the time of diagnostic arteriography. The diagnostic arteriogram is obtained, and the films are reviewed with the vascular surgeon. A decision is made concerning the best approach for the patient while the patient is still on the angiographic table. This process has led to our current approach, because it is sometimes difficult to ascertain ahead of time which lesions are best treated by angioplasty. Diagnostic angiography in patients with symptomatic vascular disease of the lower extremities is usually performed by puncturing the common femoral artery in the least symptomatic extremity. This makes the initial puncture easier because of the stronger pulse, and it simplifies passage of the guide wire through the as yet unvisualized iliac vessels. Subsequently, it also allows the angiographer the luxury of making either an antegrade or retrograde puncture in the symptomatic extremity. Once the puncture is made for the diagnostic study, a 0.03.5inch movable-core tight J guide wire is advanced into the abdominal aorta under fluoroscopic control. The J wire will usually stay within the lumen. If resistance is encountered, the core can be partially removed, creating a very soft-tipped wire which is usually easily advanced into the aorta. The diagnostic arteriogram is then obtained through a 5-F pigtail catheter. Once the decision has been made to dilate an iliac lesion, the common femoral artery on the

symptomatic side is punctured. The pulse is the best guide for the femoral puncture; however, if the pulse can not be palpated there are several options. Frequently, the hard atherosclerotic artery can be palpated even in the absence of a pu1se.38 Fluoroscopic guidance is helpful, especially if flecks of calcium can be visualized in the wall of the artery. The diagnostic arteriogram is also helpful because the course of the femoral artery over the femoral head allows the use of the bony landmarks to puncture the artery. A Doppler machine can also be used to locate the pulseless femoral artery. The easiest method, however, is to inject contrast material through the pigtail catheter in the abdominal aorta and puncture the opacified femoral artery under fluoroscopic contro1.3g Alternatively, a guide wire can be passed over the aortic bifurcation and down into the common femoral artery. The pulseless common femoral artery is then punctured using fluoroscopic guidance and the guide wire as a target.40 It is very important to puncture the femoral artery at an angle of 4.5” or less. If a steep puncture is utilized, it may be very difficult to manipulate the diagnostic catheter and in turn the balloon catheter across a tight stenosis because of the resistance at the puncture site.

Antegrade

Puncture

An antegrade puncture is usually used in superficial femoral and popliteal angioplasty. The ipsilateral common femoral artery is entered just distal to the inguinal ligaments. The inguinal crease cannot be used as a landmark because it is often several centimeters below the inguinal ligament, especially in obese patients. The puncture should be lined up with the femoral head and neck, which provide reliable landmarks (Fig 13). The antegrade puncture and insertion of the guide wire into the superficial femoral artery are aided by placing a rolled-up blanket under the patient’s buttocks. The resultant hyperextension makes it easier to puncture the artery and facilitates directing the guide wire down the superficial femoral artery instead of into the profimda femoris artery. It is important to puncture the artery at an angle as horizontal as possible. If a vertical puncture is made, it is very difficult to manipulate the catheter in the distal vessel, especially when crossing complete blocks. The common femoral artery should be punctured high enough to allow manipulation of the guide wire into the superficial femoral artery. The puncture should be made in the sagittal plane of the common femoral artery. This is done by lining up the puncture site and the common femoral artery under fluoroscopic control before so

FIG 13. Femeral puncture site. The puncture site should be lined up with the femoral head, which provides a more reliable landmark than the inguinal skin fold. The femoral artery takes a straight course over the femoral head.

the needle is inserted. The artery is punctured and a 0.035~inch movable-core tight J guide wire is passed through the needle into the artery. If the guide wire persists in entering the profunda femoris artery, a 15-mm J guide wire may aid in entering the superficial femoral artery. If the superficial femoral artery cannot be entered because the puncture is too low, it is best to remove the needle and repuncture the artery at a higher level. Once the artery is entered at the proper level, the guide wire will usually enter the superiicial femoral artery. If the guide wire persists in entering the profunda femoris artery (Fig 1481, a 5-F Tegtmeyer catheter should be inserted into the profunda femoris artery. The catheter tip is then withdrawn into the common femoral artery, with care taken not to extract the catheter from the common femoral artery. Contrast material is injected to visualize the orifice of the superficial femoral artery. A 0.035-inch, long tapered tight J wire or a Bentson wire can usually be directed down the superficial femoral artery and the 5-F catheter will follow it easily (Fig 14,B). Once the stenosis has been crossed, a 0.035-inch movable-core tight J wire or a Rosen wire should be inserted. In antegrade punctures, it is often helpful to dilate the puncture site with 6-F and 7-F vessel dilators before the balloon catheter is inCur-r

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FIG 14. Antegrade puncture. A, the profunda femoris artery branches from the common femoral artery posteriorly and laterally. The guide wire often inadvertently enters the profunda. B, if the guide wire cannot

easily be redirected into the superficial needle, a Tegtmeyer shaped catheter redirected into the superficial femoral

serted. In obese patients, it is often very helpful to employ a sheath. The sheath greatly facilitates passage of the balloon catheter through the groin in antegrade punctures. A sheath is usually not necessary in retrograde punctures. When the balloon catheter is inserted the leg should be positioned exactly as it was for the needle puncture. It is also important not to kink the guide wire at the puncture site. If a kink in the wire develops at this level, the balloon catheter will not enter the vessel. In this situation, either reposition the wire or insert a 5-F catheter, which will follow the wire, and exchange it for a new guide wire. The balloon catheter will then pass over a new wire, especially if a sheath has been used. In antegrade punctures, it is extremely important not to puncture above the inguinal ligament. If this is done, the puncture site cannot be adequately compressed after the catheter is withdrawn and severe retroperitoneal bleeding may result.

lesion can be dilated from the contralateral femoral artery,41 and an antegrade puncture can then be performed on the side of the lesion. Occasionally, if both lesions are stenosed and the surrounding vessels are straight or relatively unaffected by the atherosclerotic process, both lesions can be dilated from the contralateral side. However, if the lesions are tight and/or the aortic bifurcation occurs at an acute angle, the contralateral approach can be difficult. In this situation, Kadir et alp2 have suggested converting the retrograde approach into an antegrade catheterization. However, it is difflcult to manipulate the catheter across distal lesions with this technique. In this situation, if the common femoral artery is of normal caliber, it is easier to perform a combined puncture of the ipsilateral common femoral artery (Fig 15). The retrograde puncture is performed first in the lower aspect of the common femoral artery, and the lesion in the iliac artery is dilated. The balloon catheter is then advanced into the abdominal aorta. An antegrade puncture is then performed, entering the common femoral artery in its proximal aspect, just distal to the inguinal ligament, and the distal lesion is dilated. If the common femoral artery flow is compromised by the two balloon catheters, the iliac balloon can be exchanged for a 5-F catheter, and gentle pressure can be applied to the puncture site while the distal lesion is dilated. This approach has several advantages. It shortens

Combined

Antegrade

and Retrograde

Punctures

Occasionally, it is necessary to dilate a lesion in the iliac vessel and also a lesion in the ipsilateral superficial femoral or popliteal artery. There are several approaches to this problem. The iliac lesion can be dilated, and dilatation of the distal lesion can be postponed for several days. The iliac Curr

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femoral artery through the is inserted and the J wire artery.

91

the hospital stay because both lesions are dilated at the same time. It also offers a direct approach to both lesions. Tight stenoses or occlusions are easier to cross when the catheter is directed in a straight line. Directing the catheter across the aortic bifurcation and then across a tight lesion can be difficult in tortuous vessels because of the loss of torque control. This technique is not used often but it can be helpful in certain situations.

Contralateral

FIG 15. Combined antegrade and retrograde punctures. The retrograde puncture is performed first in the lower aspect of the common femoral artery (red catheter). The antegrade puncture is then performed entering the common femoral artery proximally, just distal to the inguinal ligament. The balloon catheter is then inserted to dilate the distal lesion.

Approach

The contralateral approach41 allows angioplasty to be performed at the time of the diagnostic study without an additional arterial puncture (Fig 16). The midstream pigtail catheter is exchanged for a 5-French Cobra catheter or a 5-French shepherd’s crook catheter. The proximal common iliac artery is selected with the catheter, and arterial pressures are obtained above the lesion. A long tapered tight J guide wire is passed down the iliac artery, and the catheter is advanced into the iliac artery above the stenosis. If the lesion can be easily crossed with the guide wire, the wire is passed across the stenosis, and the catheter is advanced through the stenosis. If the vessels are tortuous and the lesion is tight, the diagnostic catheter is exchanged for a 5-F Tegtmeyer shaped catheter which is advanced over the guide wire until it is just proximal to the lesion. The stenosis is selectively catheterized with the catheter, and a Bentson wire is carefully advanced across the stenosis, followed by the catheter. Hemodynamic pressure measurements are obtained, and heparin is given through the catheter. A 0.035~inch Rosen wire is inserted, and the cath-

FIG 16. Contralateral approach in a 59-year-old man with two block claudications. A, pelvic arteriogram demonstrates a tight lesion in the proximal left external iliac artery (arrow). B, lesion is dilated from 92

the contralateral gram obtained widely patent.

approach immediately

with an 8-mm, after dilation

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3-cm balloon, C, arterioreveals that the vessel is

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eter is exchanged for the appropriate balloon catheter. A 0.025-inch guide wire is inserted through the balloon catheter and a Y adapter is attached to the catheter. Following balloon angioplasty, a pullback pressure is obtained with the 0.025-inch guide wire still in place across the lesion. The balloon is retracted above the lesion, and a follow-up arteriogram is obtained with the wire still in place across the lesion. Alternatively, a tip deflector wire can be used to advance the diagnostic catheter across the bifurcation of the aorta. However, tip deflector wires should be used with caution because this stiffens the tip of the catheter and may cause a subintimal dissection in the proximal common iliac artery. A major disadvantage of the technique is that it is more difficult to control the guide wire when it is passed across the lesion. This is especially true in tortuous iliac vessels and in patients with an acute angle at the bifurcation of the aorta. The

technique should be used with caution in patients with proximal common iliac stenosis or atherosclerotic disease at the bifurcation of the aorta.

A,xillary Approach The axillary approach43 (Fig 17) may be used to dilate lesions in the mesenteric, renal, iliac common femoral, and superficial femoral arteries. A high brachial puncture is utilized. The brachial artery is entered just distal to the axillary crease. The artery is easier to control in this area because the artery can be compressed against the humerus, and any hematoma is less likely to injure the brachial plexus if this approach is used. The left axillary route has proved to be far superior to the right axillary approach. The left axillary route provides the straightest approach to the descending aorta and provides better control over the catheter be-

FIG 17. Axillary approach in a 70-year-old woman with uncontrolled hypertension Fibromuscular and atherosclerotic lesions are present in the right renal artery. Forty months after PTA her blood pressure stabilized at 160190 mm Hg on low doses of medication. A, selective renal arteriogram obtained via the axillary approach reveals fibromuscular dysplasia involving the distal renal artery, as well as a tight atherosclerotic stenosis (arrow) in the proximal renal artery. Curr

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B, immediately after angioplasty, the vessel is widely patent. C, arteriogram obtained 3% months later again shows wide patency. D, caudal view reveals a small filling defect (arrow), consistent with a remnant of disrupted fibrous tissue. (From Tegtmeyer CJ, Kellum CD, Ayers C: Percutaneous transluminal angioplasty of the renal artery: Results and long-term follow-up. Radiology 1984; 153:77-X%4. Reproduced by permission.) 93

cause it avoids crossing the aortic arch. The balloon catheter has a tendency to buckle in the ascending aorta when the right axillary approach is attempted. A loo-cm JBl catheter or loo-cm multipurpose shaped catheter is used to select the appropriate vessel, and a tight J guide wire or a Bentson wire is used to cross the stenosis. The catheter is advanced through the stenosis, and a ZOO-cm movable-core J wire or ,a Rosen wire is used as an exchange wire. Balloons larger than 6 mm should be used with caution in the axillaty approach. Theoretically, there is an increased risk of damage to the smaller axillary artery; however, this can be minimized by deflating the balloon carefully and rotating it as it is being inserted and removed. There is also the possibility of brachial plexus injury, but this possibility can be decreased by using the high brachial approach. If the axillary artery is small, a large balloon should be avoided. Crossing

the Lesion

It is extremely important to keep the guide wire and catheter within the lumen when crossing the

lesion. This requires careful technique and highresolution fluoroscopy. Digital subtraction road mapping is also helpful. Subintimal dilatations frequently do not remain patent and often result in complete occlusion of the vessel. Therefore, it is essential to maintain an intraluminal course. Once the decision has been made to dilate the lesion, in general, the shortest, straightest route to the lesion is employed. This approach allows the most control when crossing the lesion. The initial crossing of the lesion should be performed as atraumatically as possible. A variety of catheters and guide wires are available and new ones are continually being developed. It is clear that 5-F catheters have a decided advantage over larger selective catheters when crossing tight lesions . The precise character of the lesion should be ascertained before attempting to cross the lesion. The diagnostic catheter is advanced over a J guide wire until it is positioned several centimeters proximal to the lesion. Contrast material is then gently injected through the catheter to once again study the lesion prior to crossing it. It is very helpful to

FIG 19. FIG 18. Technique of crossing a moderately tight stenosis. The 5-F aatheter is advanced to within 23 cm of the lesion. The J is formed proximal to the lesion, and the long tapered, tight J guide wire IS then gently advanced across the stenosis. 94

Technique of crossing a tight stenosis. The 5-F straight catheter is advanced to within l-2 cm of the lesion and the tip of the catheter is directed at the center of the lumen by injecting contrast material, under fluoroscopic control. A Bentson wire is then advanced across the lesson under fluoroscopic control. Curr

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Technique of crossing lesions located at bends in the artery. A 5F Tegtmeyer catheter is advanced and rotated under fluoroscopic control until the tip of the catheter is directed at the lesion. A Bentson wire is then advanced across the lesion. It is important to cross the lesions as atraumatically as possible.

visualize the lesion in more than one projection. The image for digital mapping is obtained if the equipment is available. There are two basic approaches for crossing lesions in the extremities. Either straight catheters can be used in combination with a series of curved guide wires, or the catheter can be shaped and flexible straight guide wires, with either a tight J or a straight tip, can be utilized. Often a combination of these approaches is necessary. A 5-F Tegtmeyer catheter is a good basic catheter for angioplasty. When crossing stenoses, it is usually best to begin with J wires or flexible guide wires and progress to stiffer guide wires only when necessary. A long tapered tight J or a movable-core tight J will cross most stenoses. A 5-F catheter is advanced until it is 2-3 cm proximal to the lesion. The J wire is then directed through the center of the stenosis and across the lesion (Fig 18). In most very tight lesions, however, resistance is encountered, and it is better to cross the stenosis with a straight guide wire. A long tapered straight guide wire or a Bentson wire will cross most lesions (Fig 19). Because the Bentson wire is very flexible, this is usually the Cur-r Probl

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FIG 21. Technique of crossing lesions with a catheter. catheter is advanced over a guide wire until proximal to the lesion. The catheter is then scopic control and carefully advanced while simultaneously injected. The steady, gentle material keeps the tip of the catheter in the and delineates the path through the stenosis. this technique is that the lesion is crossed scopic control.

The 5-F Tegtmeyer it is positioned just rotated under fluorocontrast material is injection of contrast center of the lumen The advantage of under direct fluoro-

first wire used, if a straight wire is needed. When a slight curve is needed at the tip of the guide wire, the wire can be shaped by drawing it between the tip of the index finger and the thumb nail. If the vessel is tortuous or the stenosis is eccentric, a 5-F Tegtmeyer catheter (150° angled tip) is often helpful to direct the guide wire into the lumen of the stenoses (Fig 20). Another approach that is often helpful in eccentric stenoses is to gently advance the 5-F Tegtmeyer catheter across the stenosis while simultaneously injecting conallows you trast material (Fig 21). This technique to visualize the stenosis as you are crossing it. The steady flow oi contrast material keeps the tip off the wall and delineates the lumen of the vessel. If the catheter is advanced slowly and carefully, difficultlesions can be crossed. A combination of maneuvers is often necessary to cross multiple lesions in tortuous vessels (Fig 22). The 0.014- or 95

FIG 22. Technique of crossing complex lesions. A, the 5-F catheter is advanced over a J wire until it is just proximal to the stenosis, /3, the catheter is rotated and advanced while injecting contrast material. C, a long tapered, tight J guide wire is gently advanced until the

next turn in the lesion is encountered. D, the catheter is advanced and rotated. The flexible J guide wire is then readvanced across the lesion into the abdominal aorta.

O.OlS-inch platinum-tipped steerable guide wires used for tibial and coronary angioplasty can be used either by themselves or in a coaxial combination with a 0.035~inch “open-ended” or interventional guide wire when other wires have failed to cross the lesion.44 Once the diagnostic catheter has crossed the lesion, the catheter must be exchanged for the appropriate dilatation catheter. It is important to avoid trauma to the vessel distal to the lesion during the exchange. Despite precautions, the tip of the guide wire moves in the vessel during the exchange. It is important, therefore, to use a wire that is stiff enough throughout most of the length to assist the balloon catheter in passing through the lesion but flexible at the tip. There are two basic exchange wires: a 0.035-inch heavy-duty movable-core 1.5-mm J with the core withdrawn 2-3 cm, and a 0.035-inch 1.5-mm J Rosen wire.27 After the balloon catheter has been inserted, a Y adapter is attached to the catheter. A 0.025-inch 1.5-mm J guide wire is inserted through the catheter. This allows the guide wire to remain in place across the lesion during the procedure. Contrast material can be injected through the Y adapter, and pressures can be obtained with the guide wire still in position.

PHARMACOLOGY

96

At the present time, drugs are primarily used during angioplasty to prevent thrombosis and spasm. At the University of Virginia, once the diagnostic catheter has safely crossed the lesion, the guide wire is removed. The catheter is flushed, and the patient is given 2,000-5,000 IU of heparin through the diagnostic catheter. If the lesion is a short isolated stenosis and the procedure can be performed quickly, the patient is given 2,000 IU of heparin. The dose of 2000 IU will provide anticoagulation for approximately 30 minutes. However, if the procedure is thought to be complicated and time-consuming, or if the diagnostic catheter is occluding the lumen, more heparin is given. The incidence of severe groin hematomas has been reduced with lesser amounts of heparin given during the angioplasty procedure. Spasm is a frequent occurrence during angioplasty of the renal, popliteal, and trifurcation vessels. Spasm may also occur in the larger vessels, such as the iliacs, especially in heavy smokers, but it is less frequent. Spasm is usually caused by a mechanical stimulation of the vessel wall. The irritation of the vessel wall is caused by the guide wire, the catheter tip, or by inflating the balloon. The spasm may occur locally or at a distance. CalCurr

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cium channel blockers are highly effective in preventing and reversing spasm in the blood vessels. At our institution, patients undergoing angioplasty of the renal, popliteal, or trifurcation vessels receive 2.5 mg of verapamil intraarterially through the diagnostic catheter as soon as the lesion has been crossed. If a spasm is encountered, another 2.5 mg of intraarterial verapamil is given. Since we began using calcium channel blockers 3X years ago, there has been a marked decrease in the number of patients experiencing spasm during angioplasty. An alternative approach is to give patients 10-20 mg of nifedipine sublingually 15-30 minutes before the angioplasty procedure. The capsule is punctured several times with a 19-gauge needle before it is placed under the tongue. If spasm occurs in spite of the use of calcium channel blockers, intraarterial nitroglycerin in a dose of 100-200 pg is given intraarterially. Nitroglycerin is very effective in relieving spasm, but its mechanism of action is different from that of the calcium channel antagonists. It has an additive affect when given with the calcium channel blockers, so it is very effective once spasm is encountered after the blocker has been previously administered. We prefer to use calcium channel blockers initially because the duration of action is longer than that of nitroglycerin. Verapamil has the advantage of being the only calcium channel blocker available in a liquid form. Nifedipine, on the other hand, is the most potent vasodilator of the calcium channel blockers available. Calcium channel blockers may induce hypotension, and they should be used with caution in patients who have known cardiac conduction defects. It is also important to remember that the guide wire and catheters are the major cause of spasm, and that continued stimulation of the vessel wall will cause the spasm to recur. Catheter and guide wire manipulation should be kept at a minimum, and the most effective treatment of spasm is to remove the catheter and guide wire. Nicotine produces vascular spasm; therefore, smokers are encouraged to stop smoking. PATIENT

MANAGEMENT

Proper management of candidates for angioplasty requires a team approach. Proper selection of patients and the management of patients with peripheral vascular disease requires close cooperation of a vascular surgeon. Proper selection of patients with hypertension and renal vascular disease requires the close cooperation of a hypertension specialist. Inadvertent occlusion or rupture of an artery may create a surgical emergency. Therefore, the procedure should only be performed when a skilled vascular surgeon is available. Curr

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Careful postangioplasty management is very important to the long-term success of the procedure. Following removal of the catheter, the puncture site should be compressed with enough pressure to control the bleeding, yet not so firmly as to cut off blood flow through the femoral artery. If the artery is occluded, the angioplasty site may thrombose. The patient is placed on strict bed rest until the next morning and cautioned not to bend the hip at the puncture site. The condition of the peripheral pulses is established both before and after the pmcedure, and the pulses are monitored every 15 minutes for 1 hour, every 30 minutes for 1 hour, every hour for 4 hours, and then every 4 hours for 16 hours. The puncture site is checked for hematoma formation every time the pulses are monitored. Following angioplasty, unless contraindicated, patients at the University of Virginia receive 2,000 IU of heparin subcutaneously every 6 hours beginning 8 hours after the procedure and continued for 2 days. The patients are also given 75 mg of Persantine orally twice a day for 6 months, and 325 mg of aspirin once a day for life. Long-term anticoagulation with ,Coumadin is rarely used. It is reserved for patients who undergo peripheral angioplasty for limb salvage and who have extensive distal disease and poor runoff. Patients are encouraged to stop smoking and are placed on a graduated exercise program. The exercise program is tailored to the patient’s condition. Patients are encouraged to walk at least a mile a day or until they develop claudication. They are then encouraged to try and increase the amount of time they can walk until they achieve a set goal of l-5 miles a day. An exercise program tailored to the individual patient may increase the patient’s exercise capacity by as much as 25%. Patients are seen in follow-up, and noninvasive plethysmographic and Doppler studies are performed as a baseline prior to angioplasty and 2448 hours after the procedure. The studies are repeated every 3 months for the first 6 months if possible and every 6 months thereafter. If the study shows a decrease in the hemodynarnics, a repeat arteriogram is indicated to look for recurrence of the lesion or progression of the disease. ILIAC

BALLOON

ANGIOPLASTY

The presence of a significant iliac artery stenosis is one of the most frequent indications for peripheral vascular angioplasty. Technically, iliac stenoses are the easiest angioplasties to perform. The best results are obtained in these vessels because of their large size and the high blood flow. Atherosclerosis is by far the most common cause of occlusive disease of the iliac vessels. Fibmmuscular dysplasia is an infrequent cause of 97

stenosis in the iliac vessels (Fig 23). The disease involves the iliac arteries in I%-5% of patients with fibromuscular dysplasia.45’46 Postoperative anastomotic stenoses usually seen after aortofemoral or aortoiliac bypass grafts are observed in approximately 4% of the patients undergoing aortoiliac or aortofemoral reconstruction.47 Atherosclerotic lesions of the iliac vessels are frequently encountered in middle-aged patients. The lesions may be isolated or combined with lesions at the aortic bifurcation or in the distal vessels. Pa-

tients present with pain on exertion in the hips and buttocks. This pain must be differentiated from that due to arthritis or lumbar disk disease. The ischemic pain of vascular disease usually abates within 5 minutes after exercise, whereas the pain of arthritis or lumbar disk disease remits more slowly. Examination of the pulses in the extremities is critical. The femoral pulses will be absent or markedly diminished in patients with iliac artery disease. Patients with accompanying lesions in the

FtG 23. Fibromuscular dysplasia, in a 32-year-old woman who presented with bilateral claudication and hypertension. Angioplasty was performed on the renal artery and iliac vessels on the same day. A, selective right renal arteriogram showing fibromuscular dysplasia in the main renal artery (arrow). 6, lOOmm spot radiograph demonstrating a 5mm balloon dilating the lesion. C, immediately after PTA, the renal artery is widely patent. D, pelvic arteriogram demonstrating extensive fibromuscular dysplasia in both external iliac arteries, E, immediately after angioplasty, the vessels are enlarged and there is good flow. The patient is normotensive and the claudication has disappeared 17 months later. (From Tegtmeyer CJ, Tegtmeyer VL, Kellum CD, et al: Percutaneous transluminal angioplasty: The treatment of choice for vascular lesions caused by fibromuscular dysplasia. Semin Intervent Radio/ 1984; 1:289300. Reproduced by permission.) Curr

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1987

peripheral vessels will also have diminished or absent pulses in the lower extremities. Careful and considerate questioning of patients with severe iliac disease often elicits complaints of impotence. Noninvasive testing will reveal a diminution of pulse volumes and pressures in the thigh. However, superficial femoral lesions may also cause decreased thigh pressures. Angiographic

Evaluation

Once a clinical decision has been made to treat the patient, a diagnostic angiogram is necessary before a final decision on the best course of therapy can be made. Because of the diffuse nature of the atherosclerotic process, a complete angiographic workup, including an abdominal aortogram and a runoff study, is needed to fully evaluate the patient. The vessels should be completely visualized from the take-off of the renal vessels to the ankle. Lesions in the iliac arteries are often eccentric and posterior in location. Their significance is underestimated on single-plane angiograms. Therefore, it is frequently necessary to obtain oblique views of the iliac vessels to completely evaluate lesions in these vessels. High-quality angiography is necessary because the exact nature of the lesion must be delineated before a decision can be made regarding the feasibility of balloon angioplasty. A major reason for failure of angioplasty is the physician’s failure to accurately define the anatomy of the lesion before attempting the procedure. If the hemodynamic significance* of a lesion is difficult to assess angiographically, intra-arterial pressure measurements should be obtained (vide supra). This is the case in lesions which occlude approximately 50% of the lumen. Pressure mea-

surements are obtained proximal and distal to the stenosis, and a peak-to-peak systolic gradient of 10-15 mm Hg, when the patient is at rest, is significant. The best results are obtained in the distal aorta or in the iliac vessels because of the large size of the arteries and the high blood flow. Technically, angioplasties to relieve iliac stenoses are the easiest to perform. The neophyte angioplaster should gain experience in treating iliac stenoses before progressing to more difficult procedures. The ideal lesion for transluminal angioplasty is a short, isolated, concentric stenosis in the common iliac artery (Fig 241. However, multiple isolated lesions in the iliac vessels can be successfully dilated (Fig 25). A complete peripheral arteriogram is obtained using a 5-F pigtail catheter (vide supral. Since most peripheral angioplasty procedures at the University of Virginia are performed at the time of diagnostic arteriography, the diagnostic study is usually performed by puncturing the common femoral artery in the asymptomatic extremity. If the patient has bilateral symptoms, the groin with the strongest pulse is entered. This simplifies the initial puncture because of the stronger pulse, and passage of the guide wire through the as yet unvisualized iliac vessels is easier. Once the decision has been made to dilate an iliac lesion, the lesion can be approached either from the contralateral side or from the ipsilateral side. In general, the shortest, straightest route to the lesion should be used. Because this approach allows the most control when crossing the lesion, the ipsilateral approach is used unless the situation dictates otherwise (Fig 26).

Once the femoral Tegtmeyer catheter Bloomington, Ind.)

artery has been entered, a 5-F (150’ angled tip, Cook, Inc., or a straight 5-F catheter is

FIG 24. Successful iliac angioplasty of a year-old woman with intermittent reveals a stenosis (arrow) in the mm balloon is used to dilate the Curr

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short isolated stenosis in a 48claudication. A, iliac angioplasty distal common iliac artery. B, 7lesion. C, immediately after dila1987

tation, the lesion has disappeared. (From Tegtmeyer CJ, Kellum CD: Angiographic diagnosis and management of aorto-iliac disease, ‘in Traveras (ed): Radiology. Philadelphia, JB Lippincott, 1986, in press. Reproduced by permission.) 99

FIG 26. Multiple stenoses in the iliac arteries will respond to PTA. The 60year-old man presented with bilateral claudication. A, the pelvic arteriogram reveals multiple stenoses in the iliac vessels (arrows). B, arteriogram obtained immediately after bilateral PTA shows the

marked improvement in the vessels bilaterally. (From de Paredes ES, Kellum CD, Tegtmeyer CJ: Percutaneous transluminal angioplasty of the extremities: An overview. Rev hteramericana Radio/ 1983; 8:113-l 18. Reproduced by permission.)

placed in the iliac artery below the lesion. Pressure measurements are obtained through both catheters and the peak-to-peak systolic gradient is calculated. The diagnostic arteriogram should be thoroughly studied to ascertain the precise character of the lesion prior to attempting to cross the lesion. The 5-F catheter is then advanced over a J wire until it is positioned just distal to the lesion. Contrast material is then gently injected through

the catheter to once again study the lesion prior to crossing it. It is very helpful to visualize the lesion in more then one projection. The image for digital mapping is obtained, if the equipment is available. The lesion should be crossed as atraumatically as possible. There are two basic approaches to crossing lesions: either straight catheters can be used in combination with a series of curved guide wires, or the catheter can be shaped and flexible straight guide wires, such as a tight J

FIG 26. Technique of PTA in the iliac arteries. The standard retrograde puncture is made. The lesion is located, and the 5-F catheter IS advanced over a guide wire until it is just distal to the lesion. Pressure measurements are obtained. Under careful fluoroscopic guidante, a guide wire is advanced across the stenosis, and the cath100

eter follows. Pressures are obtained. exchanged for the appropriate-sized is inflated with 46 atm of pressure follow-up arteriogram is then obtained

Curr

Pmbl

The diagnostic catheter is balloon catheter. The balloon and the lesion is dilated. A to ascertain the results.

Diagn

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1987

or a straight tip, can be utilized. A combination of maneuvers is often necessary to cross multiple stenoses in tortuous iliac vessels. Once the diagnostic catheter has safely crossed the lesion and advanced into the abdominal aorta, the guide wire is removed. The catheter is flushed and &OOO-5,000 IU of heparin is injected through the catheter into the abdominal area. A balloon 3 cm long and 6-10 mm in diameter is usually utilized in the iliac vessels. Once the proper-sized balloon catheter has been selected, the diagnostic catheter is exchanged for the appropriate dilatation catheter. After the lesion has been dilated, it is very important not to retraverse the dilatation site with a guide wire. Therefore, the 0.025-inch guide wire remains across the lesion until the procedure has been completed. In this way the balloon catheter can be moved freely up and down over the wire, and the guide wire ensures the position of the catheter in the arterial lumen. Progress of the procedure can be monitored either by injecting contrast media from the contralateral catheter or by measuring pressures through the balloon catheter when the tip has been moved across the stenosis. If a residual pressure gradient is present, the dilatation should be repeated. If the lesion is still resistant to dilatation and there is still a gradient, the use of a larger diameter balloon should be considered. If possible, the end result should be a good cosmetic appearance of the lesion. Follow-up studies have shown that if greater than 30% residual stenosis is left behind, the lesion is more likely to recur.29-31 However, in very resistant lesions, when the pressure gradient across the stenosis has been reduced to zero, the procedure should be terminated. In some situations, excellence is the enemy of good, and experience is necessary to know when to stop. Most lesions will respond promptly if the proper-sized balloon is used. Following the dilatation, the balloon catheter is advanced into the abdominal aorta. A follow-up arteriogram is obtained through the pigtail catheter that was inserted in the contralateral extremity.

Complete

Blocks in the ZZiac Vessels

Angioplasty of iliac stenoses has become an accepted procedure. However, angioplasty of complete blocks in the iliac vessels remains controversial. Successful treatment of complete blocks in the iliac arteries has been reported in a limited number of cases.35’48,4g Ring et a15’ reported successful dilatation in five of ten cases; however, embolization to the contralateral leg complicated two of the successful cases. It is clear that angioplasty of complete blocks in the iliac vessels should be attempted only in very Curr

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selected cases. The dilatation of complete blocks in the iliac vessels may be indicated when patients have underlying coronary renal or carotid disease, in an attempt to avoid major surgery and general anesthesia. If the vessel is not straight, dilatation should not be attempted. If the complete block involves the proximal common iliac artery, the kissing balloon technique37 should be utilized to protect the contralateral extremity. The technique should usually be reserved for short blocks less than 2 cm long, and in these lesions good results can be obtained (Fig 27). However, in special circumstances longer blocks can be successfully dilated (see Fig 12). Recent complete occlusions are often due to fresh thrombus formation superimposed on preexisting stenosis. In this situation, an attempt to dilate the lesion may result in distal embolization. Recent thrombus does not respond to angioplasty. Recent occlusions may be given a trial with thrombolytic therapy if the clinical situation warrants. If the thrombus lyses, the underlying lesion in the iliac artery can be treated with angioplasty. Results PTA of the iliac vessels is a highly effective procedure. In experienced hands, the initial success rate is high, and because of the large size of the vessels and the high blood flow, good long-term results are obtained (Table 1).48’5*-63 In the reported series, the initial success rate varies from 75% to 100%. An initial success rate greater than 90% should be anticipated when treating iliac stenoses. At the University of Virginia, analysis of the first 197 patients with 337 iliac lesions revealed an initial success in 93.6% of lesions and 94.9% of patients. Analyses of the long-term results reported in the literature vary from 61% to lOO%, even though many of the studies were reported before the advent of high-pressure balloons. Presently, a 3-year patency rate of 85%-90% should be expected. The long-term clinical results of angioplasty depend on multiple factors-the percent residual stenosis following angioplasty, the extent of the disease, the peripheral runoff, the patient’s smoking habit, and the presence of associated disease such as diabetes. AORTIC

ANGIOPLASTY

The standard treatment for lesions in the abdominal aorta has been surgical, either endarterectomy or bypass grafting. However, now that the kissing balloon technique has been perfected and balloons up to 20 mm in diameter are available, selected lesions in the distal abdominal aorta and at the bifurcation of the aorta can be treated by 101

FIG 27. Angioplasty of a complete block in an iliac vessel in a 64-year-old woman who presented with intermittent claudication in the left leg. A, pelvic arteriogram reveals a 2.5-cm-long complete block in the

left common iliac artery. balloon. C, immediately flow across the lesion.

balloon angioplasty. It was originally believed that dilatation of lesions located at the bifurcation of vessels, especially the aortic bifurcation, was contraindicated because inflation of a single balloon might displace the plaque laterally and occlude

the contralateral iliac vessel or result in distal embolization. These lesions, however, can be successfully treated by using the kissing balloon technique.36’ 37,64J65 The diagnostic arteriogram is obtained with a 5-F pigtail catheter inserted

TABLE Results

4-cm good

1. of Iliac

Artery

Angioplasty NO. OF ITS.

STLJDY, YR

INITIAL

LESIONS

Dotter et al.,= 1974 Schoop et al.?’ 1978 Griintzig et al., 53 1979 Alpert and Ring? 1980 Colapinto et al.,55 1980 Dotter,56 1980 Motarjeme et al.,’ 1980

43 138 64 35

Waltman:’ Zeitler,”

48 206

54 206

10

10 occlusions 26 141

Colapinto

B, the lesion is dilated with a 6-mm, after angioplasty the vessel shows

1980 1980

1 45

et al.,48 1981

Neiman et al.,“’ 1982 Kadir et al.,61 1983

26 112

Katzen,“’ 1983 van Andel et al.,63 1985 Tegtmeyer et al., 1986

102 154 197

48 145 64 51 >112 1 66 arteries

SUCCESS RATE (LESIONS)

81% 77% 92% pts. 75% 100% 75% pts. 82% arteries 85% 92% pts. 80% occlusions 96% 95.7%

105 194 PTA 337

95% 96%

LONG-TERM PATENCY SATE*

LENGTH OF FOLLOW-UP

6~

100% (39139) 73% (48/66) pts. 87% (51/59) 94% (34/36) 86% 100% (l/l) 100%

1-9 mo.

95%

2yr

70% (37/54) 61% (33/54) pts. 100% (818)

3yr 5yr 3-13 mo.

3yr

2yr 2yr 14yr

2yr

92% (23125) 91.3% 89% 93% 90%

3-18

mo.

1Yr 3yr 3yr l-7yr

93.6%

94.9 pts. Total

1,216

1,518 750x-100%

-.3e ‘Based on reported 102

number

ofinitial

~u~~e~~e~thatwere

followed

61%-100%

1 mo.-14

yr

up. Curr

Rob1

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Radio&

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1987

through the femoral artery with the stronger pulse. If the lesion cannot be passed with a 0.035inch movable-core or a tight J guide wire, a 5-F Tegtmeyer catheter is inserted distal to the lesion. A long tapered, straight guide wire or a Bentson wire is then threaded across the lesion, and the catheter is exchanged for a pigtail catheter. Arteriograms of the lower abdominal region, including the renal arteries, are obtained. This is followed by runoff arteriography to evaluate the vessel from the bifurcation of the aorta to the ankles. The contralateral femoral artery is punctured, and a guide wire is threaded into the abdominal aorta. In lesions that are short, tight, and eccentric, it is often helpful to manipulate the 5-F Tegtmeyer catheter across the lesion under fluoroscopic control while injecting contrast material. Once the lesions are crossed on both sides, 2,000-5,000 IU of heparin is injected into the aorta. Balloon catheters of the appropriate size are then advanced through the lesions simultaneously (Fig 28,A) over 0.035-inch movable-core tight J guide wires. The balloons are positioned across the lesions so that the proximal portions are in the abdominal aorta and the distal ends are in the iliac arteries. The balloons are then inflated

simultaneously, trapping the atherosclerotic lesions at the bifurcation between the two balloons (Fig 28,B). The size of the balloon is determined by measuring the size of the artery proximal and distal to the lesion and estimating the original size of the artery in the area of the lesion. If the artery is estimated to measure 8 mm in diameter, this is the balloon size selected (Fig 29). If the aggregate diameter of the two balloons exceeds the size of the distal abdominal aorta, a smaller balloon is used on the normal side or the side with the less severe lesion (Fig 30). If the dilatation is inadequate, the balloons are reversed and reinflated. The balloons are inflated two to three times for 30-60 seconds at each inflation. Sufficient pressure is utilized to expand the balloon fully. In resistent lesions, up to 10 atm of pressure is required. After angioplasty, a repeat arteriogram is obtained through a pigtail catheter to assess the status of the dilatation. A good result can usually be anticipated after dilatation of aortic bifurcation lesions. Selected lesions in the distal abdominal aorta can be treated by balloon angioplasty (Fig 31) .37,66-7o Only short, discrete, focal lesions in the abdominal

FIG 28. Kissing balloon technique. A, the lesion at the bifurcation of the aorta has been crossed with guide wires inserted through both common femoral arteries. 6, the balloons are positioned across the lesion so that the proximal portions are in the abdominal aorta and the distal ends are in iliac arteries. The balloons are inflated simultaneously. trapping the atherosclerotic plaques at the bifurcation Curr

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between the two balloons. (From Tegtmeyer CJ, Kellum CD, Kron IL, et al: Percutaneous transluminal angioplasty in the region of the aortic bifurcation: The two-balloon technique with results and longterm follow-up study. Radiology 1985; 157:661-665 Reproduced by permission.)

103

FIG 29. Kissing balloon technique performed in a 52-year-old woman with claudication and a unilateral lesion at the bifurcation of the aorta. A 69 mm Hg peak-to-peak systolic gradient is present across the lesion. A, pelvic arteriogram reveals a tight, eccentric stenosis (arrow) at the bifurcation of the aorta. B, balloons are shown inflated. An a-mm balloon is present on the right, and a 6-mm balloon is inflated protecting the left iliac artery. C, follow-up arteriogram obtained immediately after PTA demonstrates widely patent arteries. The gradient has been reduced to zero. The patient was asymptomatic 32 months after the procedure. (From Tegtmeyer CJ, Kellum CD, Kron IL, et al: Percutaneous transluminal angioplasty in the region of the aortic bifurcation. Radiology 1985; 157:661-665. Reproduced by permission.)

aorta should be treated by angioplasty. These lesions often occur in patients with small aortas, and some of the patients have what has been described as hypoplastic aortic syndrome.71’72 These patients are young women (30-50 years of age) who are heavy smokers, and they have relatively small vessels. The lesions are often focal and may occur anywhere in the aorta below the renal arteries, but are often located immediately above the aortic bifurcation. The technique is similar to the techniques that have been described for the iliac and aortic bifurcation lesions. The lesions can be treated with a single large balloon or with the kissing balloon technique. A single large balloon will produce a better cosmetic result (Fig 321. However, some patients have very small liac vessels, and it is safer to treat these patients with two smaller balloons. This avoids stasis in the iliac vessels during the procedure. One major difference in technique exists because the aorta is a larger vessel than the peripheral vessels, and it does not withstand as much pressure. Balloon dilatation is governed by the law of Laplace. Therefore, the larger the radius of the vessel, the greater the wall tension during inflation of the balloon. Large balloons do not withstand the same amount of pressure that smaller balloons do. The same is true of larger ves104

sels. Aortic rupture after balloon dilatation has been reported.73 Aortic lesions, therefore, should be slightly underdilated, not overdilated, to avoid rupturing the aorta. Care should be taken to avoid injury to the inferior mesenteric artery or an aberrant renal artery during dilatation of lesions in the abdominal aorta (Fig 331. If the origins of these vessels are in the area of the dilatation, the lesion should be approached with caution. When the clinical situation warrants angioplasty, these vessels should be protected. Either the lesion should be underdilated or two guide wires should be utilized. One wire should be placed in the branching vessel and the other wire through the lesion. If the angioplasty procedure compromises the origin of the vessel, a balloon can then be placed in the branching vessel to correct the problem. At the University of Virginia, 61 atherosclerotic lesions were treated in 32 patients with the kissing balloon technique.37 Two of the lesions involved the hypogastric arteries. The remainder were located in the distal abdominal aorta or at the bifurcation of the aorta (Fig 34). Fifty-eight lesions in 30 patients were successfully dilated. Short isolated stenoses in the abdominal aorta have also been successfully treated with the single balloon technique. Cut-r

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1987

Psys

FIG 30. Kissing balloon technique demonstrated in a 47-year-old woman with bilateral claudication. A, pelvic arteriogram shows localized, tight, circumscribed stenosis (arrow) in the distal abdominal aorta just above the aortic bifurcation. Note the collaterals. B, two 6-mm balloons are shown inflated, dilating the lesion in the distal abdominal aorta. C, follow-up pelvic arteriogram shows widely patent distal abdominal aorta (arrow). D, plethysmography and Doppler ultrasound pressure studies at the ankles, after exercise, before and 7 weeks after the procedure. Pulse waveforms and pressures in the ankle returned RN: Balloon dilation of the abdominal aorta. JAMA 1980; 244:2636-2637. by permission.)

COMMON

FEMORAL

ANGIOPLASTY

Lesions in the common femoral artery are infrequently treated with balloon angioplasty. This is probably because when the common femoral artery is involved with severe atherosclerotic disease, either the iliac artery contains diffuse disease or the superficial femoral artery is occluded. Either the contralateral femoral approach41 or the axillary approach 43 is used to dilate these lesions. The lesions are usually dilated with a balloon 5 mm or 6 mm in diameter and 2 cm long (Fig 35). Care must be taken to avoid occluding the origins of the superlicial femoral and profunda femoris vessels. Curr

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1987

Psys

70 mmHg

75 mmHg

7 WEEKS

Psys

120 mmHg

Psys

120

mmHg

J

to normal at 7 weeks. (From Tegtmeyer CJ, Wellons HA, Thompson Copyright 0 American Medical Association, 1980. Reproduced

PROFUNDA

FEMORIS

ANGIOPLASTY

The profunda femoris artery supplies blood to the muscles of the thigh and provides the major collateral circulation to the distal leg when the superficial femoral artery is occluded. Patients with total occlusion of the superficial femoral artery and poor distal runoff are often not considered good candidates for vascular bypass surgery. In this situation, if the profunda is stenosed, two options are available: surgical endarterectomy or angioplasty of the lesion. Surgery is limited to proximal lesions. In patients with superficial femoral artery occlu106

FIG 31. Images of 47-year-old diabetic woman with severe bilateral calf and thigh claudication and pain in the left extremity at rest. Her clinical history included a 20 pack-year smoking habit and two previous myocardial infarctions. A, pelvic arteriogram shows a hypoplastic aorta with disease at aortic bifurcation and in proximal iliac arteries (arrow). B, balloons are shown inflated, dilating the lesions. C, immediately after PTA, marked improvement was noted

in the vessels. After 4 months, patient states that she walks up four flights of day. Comment: The case illustrates the syndrome. (From Tegtmeyer CJ, Kellum taneous transluminal angioplasty in the cation Radiology 1985; 157:661-665. sion)

sion, it is very important to search for lesions in the profunda femoris artery. Angiography must be performed in the oblique projection. The profunda femoris artery arises from the posterolateral aspect of the common femoral artery. Therefore, the origin is best demonstrated by obtaining an oblique view by elevating the side to be evaluated (Fig 361. The approach to the artery varies depending on the anatomy. If the bifurcation of the vessel is low, the ipsilateral femoral artery can be utilized. However, if the bifurcation is high, then either an axillar~~~ or a contralateral femora141 approach is utilized. A 5-F Tegtmeyer diagnostic catheter is usually employed to select the vessel and cross the lesion. A balloon catheter 4-5 mm in diameter and 2 cm long is usually adequate to dilate the lesion. Few cases of dilatation of the profunda femoris artery have been reported.58’74 This is due in part to the fact that endarterectomy of the profunda

can be performed under local anesthesia. However, dramatic results can be obtained by balloon angioplasty. Motarjeme et al. were successful in all 12 patients who were treated by balloon angioplasty.74

199

was asymptomatic and stairs several times each hypoplastic or small aortic CD, Kron IL, et al: Percuregion of the aortic bifurReproduced by permis-

SUPERFICLAL FEMORAL AND POPLITEAL ANGIOPLASTY

PROXIMAL

Dotter and Judkinsl first described PTA in 1964. Their first patient was an St-year-old woman with a tight focal stenosis in the superiicial femoral artery. Despite initial skepticism, two decades later, PTA has gained wide acceptance and become a viable alternative to bypass surgery in selected lesions. Now, the presence of symptomatic atherosclerotic lesions in the superficial femoral and popliteal arteries is a frequent indication for angioplasty. Curr

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FIG 32. Example of single large balloon used to dilate an aortic lesion. The 75year-old man presented with bilateral claudication in the buttocks and thighs. A, abdominal arteriogram reveals an isolated le-

sion in the lower aorta (arrow). B, loo-mm spot radiograph shows the 15-mm, 3-cm balloon inflated across the lesion. C, follow-up arteriogram shows a widely patent abdominal aorta.

The patient should undergo thorough clinical evaluation and a complete arteriographic study from the renal arteries to the ankles before a decision is made to dilate a lesion. Since most balloon angioplasties at our institution are performed at the time of the diagnostic arteriography, the diagnostic arteriogram is obtained by puncturing the common femoral artery in the least symptomatic extremity. This allows an antegrade puncture to be made in the ipsilateral femoral artery, if a decision is made to treat the patient with IVA. In selected short stenoses located in the proximal superficial femoral artery or at the origin of the superficial femoral artery, the contralateral approach is used. If stenoses are present in the origins of both the superficial femoral artery and the profunda femoris artery, the kissing balloon technique will protect the origins of both vessels and produce a better result (see Fig 36). However, for most lesions located in the superficial femoral and popliteal arteries, the ipsilateral femoral approach (Fig 37) is preferred. The approach provides the shortest approach to the lesion and optimum control when crossing the lesion. The diagnostic arteriogram is used to locate the puncture site. A blanket is placed under the patient’s buttocks, and the leg is placed in the position it was placed in for the diagnostic arteriogram. Using the bony landmarks from the arteriogram, the angiographer places the puncture below the inguinal ligament but high enough to allow manipulation of the guide wire

into the superficial femoral artery. A 0.035inch movable-core J wire is inserted through the needle and directed into the superficial femoral artery. If the guide wire preferentially enters the profunda femoris artery, the needle is directed medially toward the origin of the superflcial femoral artery. If this approach fails, the guide wire is directed laterally, which will deflect the tip off the lateral wall of the vessel and into the superficial femoral artery. If this fails, a 5-F Tegtmeyer catheter is used to direct the wire down the superficial femoral artery. Once the superficial femoral artery is entered, the guide wire is advanced until it is just proximal to the lesion. The catheter is then advanced over the guide wire until it is 4 or 5 cm above the lesion. Dilute 30% contrast material is injected to visualize the lesion in multiple projections and to ascertain the exact location and character of the lesion. In the superficial femoral, popliteal, and trifurcation vessels, 30% contrast media provides adequate opaciflcation, diminishes the pain associated with the injection of full strength contrast material in the vessels, and decreases the spasm associated with injection of concentrated contrast material into the vessels.

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Stenoses

If the vessel is straight is present, a 5-F straight

and a concentric stenosis catheter is used to direct 107

FIG 33. Atteriograms of a 61-year-old woman illustrate dilatation of localized lesion in midabdominal aorta and lesion in right common iliac artery. Patient complained of claudication in the right buttock and leg. A, abdominal arteriogram demonstrates an isolated lesion in the midabdominal aorta (top arrow) and a tight eccentric stenosis in the common iliac artery (bottom arrow). B, 6-mm and 7-mm balloons are shown dilating the aortic lesion. C, inflated balloons are shown dilating the iliac lesion. D, immediately after PTA, vessels are markedly improved. The patient was asymptomatic 3 months after dilatation. Comment: Abdominal aortic lesion was purposely underdilated to preserve the inferior mesenteric artery. (From Tegtmeyer CJ, Kellum CD, Kron IL, et al: Percutaneous transluminal angioplasty in the region of the aortic bifurcation. Radiology 1985; 157:661-665. Reproduced by permission.)

a Bentson wire across the stenosis. The catheter is advanced over a guide wire until it is 2-3 cm above the lesion. Contrast material is injected to visualize the lumen, and the catheter tip is directed toward the lumen in the center of lesion. A 0.035-inch Bentson wire is gently advanced across the lumen under fluoroscopic control or by using digital road mapping. Once the wire is across the lesion, the catheter is advanced across the lesion. In eccentric stenoses, a 5-F Tegtmeyer catheter is used to direct the wire through the lesion. It is very important to advance the wire slowly. If the

wire buckles and resistance is felt, stop and redirect the wire. In eccentric stenoses it is often helpful to gently inject contrast material while simultaneously advancing the catheter. The catheter tip can be directed under direct fluoroscopic control into the oritice of the lesion with this technique. If no resistance is encountered, the catheter is advanced across the lesion. If resistance is encountered, a Bentson wire or a long tapered J guide wire is very gently advanced out of the catheter and across the lesion. Another technique that is helpful is to use a taCurr

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i FIG 34. Locations of 61 atherosclerotic lesions treated with the kissing balloon technique in 32 patients. Numbers represent numbers of lesions. (From Tegtmeyer CJ, Kellum CD, Kron IL, et al: Percutaneous transluminal angioplasty in the region of the aortic bifurcation. Radiology 1985; 157:661-665. Reproduced by permission.)

pered Staple-van Andel catheter with a side hole proximal to the tip, as described by Zeitler. By attaching a Y-adapter to the catheter, contrast material can be injected to monitor the progress of the Bentson wire as it is advanced across the lesion. A O.OlCinch or 0.01%inch platinum-tipped steerable guide wire can be used to cross difficult tortuous lesions. If multiple stenoses are present, a combination of techniques is necessary to cross the lesions (Fig 38). Once the catheter is across the stenosis, blood is aspirated to ascertain the intraluminal position of the catheter. Dilute contrast material is injected to confirm the position of the catheter. Heparin, Z,OOO-5,000 IU, is injected. If the lesion is in the popliteal artery, or if a guide wire will enter the popliteal artery, 2.5 mg of verapamil is injected to prevent spasm. Before the use of antispasmotics, spasm was a frequent complication during popliteal angioplasty. If spasm occurs despite the use of calcium channel blocker, 100-200 ,cLgof nitroglycerin is administered through the catheter. Every attempt is made, however, to keep the guide wires above the knee to avoid spasm. An exchange wire is then inserted, either a 0.035inch movable-core J or a 0.035-inch Rosen wire. The catheter is exchanged for the appropriate balloon catheter, usually either a 5- or 6-mm-diameter balloon that is 4 cm long. In the presence of multiple lesions, a 6- or lo-cm-long balloon is used. If possible, the length of balloon is chosen so that repeated overlapping dilatations are not necessary. In long lesions, this is not possible and generally

FIG 35. Femoral artery angioplasty in a 54-year-old man who presented with claudication. A, arteriogram shows a tight stenosis in the proximal common femoral artery. B, after angioplasty with a 6-mm balCum

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loon from the contralateral approach, a good result has been obtained. C, close-up view of good result. The 0.025-inch wire is still in place, while lesion (arrow) is checked. 109

FIG 36. Balloon dilatation of origins of profunda femoris and superficial femoral arteries using the kissing balloon technique. A distal superficial femoral lesion was also dilated in this 75-year-old man. A, oblique pelvic arteriogram demonstrates the stenoses at the origins of the superficial femoral and profunda femoris vessels (ar-

rows). B, loo-mm spot radiograph shows the balloons in place. One balloon was inserted through the ipsilateral femoral artery, the other through the contralateral femoral artery. C, follow-up angiogram shows a good result. Both vessels are improved.

the distal lesions am dilated first, and the catheter is withdrawn to dilate the more proximal portions of the vessel. If a tight proximal stenosis is present, however, it may have to be dilated first to allow passage of the balloon. A 7-F dilator should be inserted to dilate the puncture wound before the balloon catheter is inserted. In obese patients, a vascular sheath is helpful if resistance is encountered at the groin when the balloon is inserted. Once the balloon has been inserted, a 0.025-inch

.I guide wire is inserted and the Y adapter is attached to the catheter. The balloon is positioned and the lesion is dilated. Following dilatation, a follow-up arteriogram is obtained with the 0.025inch wire still in place. The desired end result is a good cosmetic appearance on the arteriogram. If the lesion does not look good, it is redilated. Good results can be expected in short stenoses in the superficial femoral artery (Fig 39) and the proximal popliteal artery (Fig 40).

FIG 37. Technique of PTA in the superficial femoral and popliteal arteries. An antegrade puncture is made, the lesion is localized, and the catheter is advanced until it is just proximal to the lesion. Under careful fluoroscopic guidance, a guide wire is advanced through the lesion, and the catheter follows. The diagnostic catheter is then exchanged for the appropriate-sized balloon catheter. When inflated, the balloon dilates the lesion and restores patency of the vessel. (From Tegtmeyer CJ: Balloon angioplasty: Putting catheters to work in place of the scalpel. Diagn Imaging 1983; 5:40-48. Reproduced by permission.)

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FIG 38. Technique for crossing multiple stenoses in the superficial femoral artery. The 5-F Tegtmeyer catheter is advanced under direct fluoroscopic control as contrast material is gently injected. The catheter is threaded across the lesions as contrast material is simultaneously injected. If resistance is encountered, a long tapered guide wire or a Bentson wire is advanced across the lesion.

Occlusions The techniques used to cross complete blocks in vessels are somewhat different from the techniques employed to cross stenoses. The catheter is placed several centimeters above the block and 30% contrast material is injected. Collateral vessels opacify the distal side of the block. The block is often shorter than it appeared on the angiographic films. In total occlusions of the superficial femoral and popliteal arteries, the vessel usually ends in a cone-shaped depression. A straight 5-F catheter or a Staple-van Andel catheter with a side hole is advanced while contrast material is injected until it

is immediately above the block and the tip of the catheter is directed into the cone. In many cases, when a short block is present, a long tapered or a Bentson wire can be easily passed through the block without feeling any resistance. No force should be applied to the wire. If resistance is encountered, another approach should be tried because the straight wire has a tendency to pass subintimally as force is applied. If resistance is encountered, a 0.035inch movable-core J with the mandrel immediately behind the J is advanced out of the catheter. Once the J forms in the artery, the J guide wire and the catheter are advanced as a unit to the proximal end of

FIG 39. Angioplasty of a superficial femoral artery stenosis in a 71-year-old woman. A, arteriogram reveals a tight stenosis in the superficial femoral artery. B, the 5-mm-diameter, 4-cm-long balloon is shown Curr

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dilating the lesion. The lesion is marked PTA, the vessel is widely patent,

with

a hemostat.

C, after

111

FIG 40. PTA of tight stenosis in the popliteal artery performed in a 73-yearold woman with claudication and poor runoff. A, arteriogram demonstrates a tight stenosis in the proximal popliteal artery. B, spot

film shows the 4-mm balloon catheter in place. lowing PTA, the stenosis has disappeared.

the block. The J guide wire is then advanced through the block. If resistance is encountered and more force is needed, the catheter is advanced until it is just above the J, and the catheter and wire are advanced as a unit. This is done in the hope that the J will provide a broader and more blunt front and thus have less of a tendency to pass subintimally. The block is usually composed of organized thrombus superimposed on a preexisting atherosclerotic lesion. The atherosclerotic lesion originally narrowed the vessel to the point where it occluded with thrombus. The vessel then clotted back to a point just below a major collateral which kept the proximal portion of the vessel open. This is why the guide wire can often be advanced through the proximal portion of the block with ease. However, resistance is encountered at the distal end of the occlusion. This is where the failures occur. The stiff J wire will usually pass through the atherosclerotic lesion and into the open lumen below. However, if resistance is encountered, contrast material is injected in the block, and this will often reveal the true lumen. If the lumen is straight ahead, a movable core J with the mandrel fully inserted to produce a straight guide wire can be advanced through the distal part of the block. Once the wire is across the occlusion, the wire will be felt to pass easily in the vessel. The mandrel can then be withdrawn slightly, and the J will reform if it is within the lumen. If the wire is intramural, the J will not reform. If the distal lumen is somewhat eccentric, a 5-F Tegtmeyer catheter can be advanced over the wire

and into the occlusion, and a long tapered or Bentson wire can sometimes be redirected through the distal end of the occlusion. Once the wire has passed the lesion, the catheter is advanced over the wire into the patent vessel below the block. Blood is aspirated to ensure that the catheter is within the vessel and dilute contrast material is injected to coniirm the position of the catheter. If the wire passes into the intraluminal portion of the vessel during negotiation of the lesion, this should be recognized either by noting the increased resistance to the passage of the wire or by injecting contrast material. If the guide wire has passed below the expected end of the block and resistance is still felt, the wire is probably subintimal. If a false passage in the wall or a perforation of the vessel develops, the procedure should be terminated. The block will rethrombose and no complications will develop. However, repeated attempts to recanalize the vessel may occlude valuable collateral, especially in the distal popliteal artery and jeopardize the limb. Occasionally, the lesion is so rigid that the 5-F diagnostic catheter crosses the lesion but the balloon catheter will not follow the wire across the lesion. In this situation, the lesion can usually be predilated with a Staple-van Andel catheter. The balloon will then cross the lesion. If the patent vessel above the block ends in a collateral vessel, angioplasty should not be attempted unless the true course of the vessel can be ascertained and the guide wire can be easily directed past the collateral into the occluded lumen.

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If the patient has had a recent increase of symptoms and a complete block is demonstrated on the arteriogram, recent thrombosis should be considered. When the angiographic appearance of the occlusion and the clinical history are suggestive of recent thrombosis, angioplasty should not be attempted without first giving thrombolytic agents. This decreases the incidence of distal embolization and may convert a complete block into a stenosis, which is easier to dilate.75-78 Once the balloon catheter is across the block, the technique is the same as that used to dilate stenoses in these vessels (Fig 41). Again, every attempt should be made to avoid spasm by keeping the guide wires above the knee if possible. A 0.025 inch guide wire is kept across the lesion until the final films have been reviewed and a successful result is obtained. Excellent is sometimes the enemy of good. Attempts to retraverse previously dilated segments can result in complete occlusion of the vessel if a wire is not kept across the lesion until the procedure is finished. Results Angioplasty of lesions in the superficial femoral and proximal popliteal vessels has evolved into a highly effective technique. Analysis of the results reported in the literature (Table 2)53J55,5sS7S6reveals an initial success rate ranging from 76% to 90%. In stenoses, success varies from 80% to 90%, and in total occlusions from 76% to 90%. The ini-

tial success of the procedure is predicated on the ability of the angiographer to cross the lesion. Crossing the lesion is generally easier in stenoses because total occlusions must be crossed without visualization of the underlying atherosclerotic lesion. The experience of the angiographer has a direct bearing on the initial success rate of the procedure. Krepel et al.86 found a 77% initial success rate in their first 77 procedures and a 91% initial success rate in their last 87 procedures. The clinical results of the procedure are usually evident within 24 hours. The capillary refill improves, the pulses are restored if the distal vessels are patent, the noninvasive parameters improve, and the patient experiences improvement in symptoms. The long-term results of femoral popliteal angioplasty are approximately 70% at 3 years for stenoses (see Table 2).53S55,5sJ 7s-s6 The long-term success rate in occlusions is lower, varying from 57% to 70% in most series. However, the length of the occlusion has a direct bearing on the long-term success rate, which is usually inversely proportional to the length of the lesion. Martin et al.‘l found the patency rate following successful dilatation of occlusions 4 cm or shorter was 63%, whereas in occlusions 5 cm or longer it was 44%. There was no significant difference in the duration of patency between successfully treated stenoses and occlusion in the series reported by Krepel et al.‘” Most angioplasters, however, agree that patients with superficial femoral and popliteal occlusions greater than 10 cm are less optimal candi-

FIG 41. A complete block in the proximal popliteal artery is corrected by PTA in an 85year-old man with limb-threatening ischemia. A, arteriogram shows a long block in the proximal popliteal artery. B, loo-mm spot radiograph shows the balloon dilating the lesion. C, Cur-r

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immediately (From de transluminal americana

following angioplasty, the vessel is widely patent. Paredes ES, Kellum CD, Tegtmeyer CJ: Percutaneous angioplasty of the extremities: An overview. Rev InterRadio/ 1983; 8:113-l 18. Reproduced by permission.) 113

TABLE

2.

Results

of Femoropopliteal

Angioplasty NO. OF LESIONS

STIJDY, Y8

Gtintzig Katzen Colapinto Greenfield, Zeitler.”

ITS.

et al.,53 1979 and Chang7’ 1979

236 18

et al.,55 1980 1980

64

1980

Martin

et al.,”

1981

Spence Tamura

et al.,8’ 1981 et al.,83 1982

Lu et al,,&2 1982 Pmbst Krepel

46 108 29 21

et al.,= 1983 et d.,8” 1985

57 129

>708

Total

INITLAL SUCCESS RATE (LESIONS)

LESIONS

236 18 (8 occlusions) >60 64

84%

619

84%

90%

164 (37 occlusions1

68.2%

1

80% 57%

1 2

76% patients

67% (14/21)

pts.

Y-2

70% 77% 70% 60%

>1,624

of initial SUCCESSESthat were followed

dates for angioplasty. Nonetheless, in patients (with long occlusions) who are not candidates for surgery, successful PTA can be performed. Lu et al.84 reported an initial success rate of 76% and a limb salvage rate of 71% in a series of 21 patients with long superficial femoral occlusions. The long-term patency rate following angioplasty of stenoses and short blocks compares favorably with saphenous bypass grafts. Cutler et aLs7 found a S-year patency rate of 85% in saphenous vein femoropopliteal bypass grafts in patients with good runoff. The patency rate, however, dropped to 65% in patients with poor runoff. Martin et aLa compared the long-term results in 46 patients with occlusions who were successfully treated with angioplasty, and the results of 133 femoropopliteal grafts performed during the same period at their institution. The Z-year patency after successful PTA was 68.2%, while the Z-year patency after surgery was 42.1%. If only saphenous grafts were analyzed, however, the 2-year patency was 56.3%. A comparison between the reported results of surgery and of angioplasty is difficult because of the existence of numerous variables and their lack of standardization. However, it appears that the long-term patency of saphenous grafts is probably slightly superior to the results after angioplasty, while angioplasty is superior to bypass grafts performed with any other material. Further, repeat angioplasty is much easier to perform than the 114

76% occlusions 84% 90%

76%-90% number

1 1

70% 87% 81% 70%

84%

bie

*Based on reported

72% 75% (6181

81%

(471 occlusions) 46 occlusions 122 29 (21 occlusionsj >21 occlusions

LENGTH OF FOLLOW-UP kT4

LONG-TEFW PATENCY IWIE*

57%-87%

%-7

up.

surgical repair of failed grafts. Additionally, angioplasty preserves the saphenous veins, allowing them to be used for coronary and carotid surgery, if necessary. DISTAL POPLITBAL, ANGIOPLASTY

PERONEAL,

AND TIBIAL

Until recently, angiographers have been reluctant to dilate lesions in the distal popliteal artery and its branches. There were several reasons for the reluctance. These vessels frequently go into spasm with minimal mechanical stimulation of the vessel wall. The vessels are small, and if the spasm is not relieved promptly, thrombosis may result. Lesions in these vessels are rarely an isolated event. The lesions are usually associated with diffuse disease, and the patients are often diabetics. Finally, until very recently, adequate small balloon catheters were not available, and these lesions had to be dilated with Staple-van Andel tapered Teflon catheters. Now that spasm can be controlled pharmacologically and new miniballoons (Fig 42) are available, lesions in these vessels can be treated with angioplasty (Fig 43). Because complications may result in limb loss, however, these vessels should be approached with caution and only by experienced angioplasters. After a diagnostic arteriogram has been obtained, through the contralateral femoral artery, the lesion is approached from the ipsilatCurr

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FIG 42. Miniballoons for angioplasty. A 2.5-mm-diameter, 2-cm-long balloon on a 4.5-F catheter is shown (left). It takes a 0.028-inch wire (Cook, Inc., Bloomington, Ind.). A 3.0-mm-diameter, 2-cm-long balloon on a 4.3-F catheter (middle) takes a 0.018-inch wire (Advanced Cardiovascular Systems, Temecula, Calif.). A 3.0.mm-diameter, 2.5-cm-long balloon on a 4.3-F catheter (right) takes a 0.014-inch wire (USCI, Billerica, Mass.).

eral femoral artery. The retrograde approach allows better control over the catheter and guide wires, and many of the lesions are firm or difficult to cross. A sheath is usually inserted into the proximal superficial femoral artery. A 5-F catheter is ad-

vanced over the guide wire to a level just above the knee. To reduce the possibility of spasm, dilute nonionic contrast material mixed with Xylocaine is injected to completely visualize the lesion. Before any manipulation, 5,000 IU of heparin and 2.5 mg of verapamil are injected. The lesion is then crossed with either a 0.035inch Bentson wire or a 0.035-inch floppy curved wire. If these guide wires will not cross the lesion, a 0.014-inch or 0.018-inch steerable guide wire is used. Complete blocks are crossed with a straight 0.035~inch Bentson wire or 0.035~inch long tapered straight wire. Subintimal passage of the guide wire must be avoided. The use of a catheter with one side hole and a Y adapter is helpful, because contrast material can be injected to monitor the passage of the guide wire. Road mapping may also be helpful. Once the guide wire is across the lesion, the catheter is advanced through the lesion. If spasm is encountered, either an additional 2.5 mg of verapamil or 100 kg of nitroglycerin is injected. The diagnostic catheter is then exchanged for the appropriate 4.3-F or 5-F balloon catheter, and the lesion is dilated. If the balloon will not cross the lesion, the lesion is predilated with a 6-F Staple-van Andel catheter. If one of the trifurcation vessels is successfully dilated and others are amenable to dilatation, they may be attempted. The peroneal artery is a direct continuation of the popliteal artery, so it is the easiest artery to catheterize. The tibial ar-

FIG 43. Angioplasty of the peroneal artery in a 59-year-old diabetic man with a previous femoropopliteal graft who presented with a nonhealing ulcer in his foot. A, arteriogram shows a tight stenosis (arrow) in the peroneal artery. The distal anastomosis of the graft is CUIT Probl

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seen. The tibia1 vessels are occluded. 6, 2.5-mm place. C, follow-up digital arteriogram demonstrates suit. The stenosis (arrow) has disappeared.

miniballoon the good

in re-

115

teries arise at an angle, so an angled catheter is used to direct the guide wire into the artery. As in all dilatation procedures, the guide wire should remain in place across the lesion until the procedure has been completed and assessed with contrast material. Because of the propensity for these lesions to occur in patients with severe diffuse atherosclerotic disease, the results are not as -good in these vessels as in the proximal vessels. However, the reported results are encouraging. Greenfield et al.” achieved an initial success in 18 of 29 angioplasty attempts in the popliteal arteries and in five of six tibial lesions. Sprayregen et al.” were initially successful in all six tibial lesions they attempted. However, only two of the patients had lasting improvement. Tamura et alB3 performed tibial-popliteal angioplasty on 31 patients, five of whom had tibial disease treated. Angioplasty was technically successful in 29 cases. Their 2-year patency rate was 57%. Starck et al.” reported the results of 149 dilatations in 111 patients with popliteal and tibial disease. Surprisingly, their early results were the same in popliteal occlusions (90%) and popliteal stenoses (89% 1. In the tibial lesions, they were successful in 91% of occlusions and 81% of stenoses. The clinical success rate for the group, however, was 58%. Clinical success rates of 57% and 58% are not surprising in these vessels because clinical success depends on total blood flow, and these patients have poor outflow and diffuse disease. Most of the lesions in these initial series were treated with Staple-van Andel catheters. Today, there is better control of spasm, vastly improved balloons, and improved guide wires. In the future, the initial technical results will be vastly improved. However, the problems of underlying disease and poor outflow remain the same. The high success rate seen in proximal lesions is not yet achievable below the knee. RENAL

ANGIOPLASTY

Data from the United States National Health Examination Survey indicate that hypertension (blood pressure 5 160/95 mm Hg) occurs in lO%15% of the adult population in this country?’ Of this group of approximately 23 million persons, one million (= 4%) have potentially correctable renovascular hypertension.g1 Coronary artery disease, stroke, and renal failure have all been unequivocally related to uncontrolled hypertension,g2, g3 and renovascular hypertension poses the additional threat of progressive renal insufficiency. Pharmacotherapy and surgical revascularization, the traditional modes of treatment, have signifi-

116

cant shortcomings. In many cases, drugs only partially control blood pressure; and when several drugs are combined, side effects and/or patient compliance can become a problem.W’s6 If the renal artery is severely stenosed, lowering the blood pressure by medical therapy will further reduce renal blood flow and may result in ischemic atrophy or even renal infarction. Hunt et al?’ demonstrated conclusively that surgical correction of renovascular hypertension was superior to medical therapy. After 7-14 years of follow-up, 84% of their surgically treated patients were alive, compared to only 60% of those treated medically. Therefore, whenever possible, the treatment of choice for renovascular hypertension should be correction of the renal artery stenosis. However, surgery requires general anesthesia, and many patients are poor risks because of severe dilfuse atherosclerotic disease, renal insufficiency, or both. Moreover, surgical results vary; there is considerable morbidity, and the mortality rate can be as high as 5.9%.” While surgery and medical therapy have significant benefits in spite of these shortcomings,gg’*OO there is no question that alternative treatment modalities are desirable. Since the introduction of percutaneous transluminal renal angioplasty PTRA) by Griintzig et allo in 1978, the procedure has become the treatment of choice for correction of hemodynamically significant renal artery stenoses, whenever technically feasible. PTRA has proved to be a highly successful method for correcting renal artery stenoses.24, 2%31,102-11.5

Etiology

of Renal Artery

Stenoses

There are many causes of stenoses in the renal arteries. However, the majority of renal artery lesions are atherosclerotic in origin, and most of the remainder are due to fibromuscular dysplasia. Of the 2,442 hypertensive patients who were studied in the Cooperative Study on Renovascular Hypertension, 884 had renal artery lesions. Atherosclerosis was the etiology in 557 (63.0%1, fibromuscular hyperplasia in 286 (32.4%1, and miscellaneous disease entities in 41 (4.6% 1.” In the University of Virginia seriesF4 atherosclerosis was the etiologv of the stenosis or occlusion in 75 patients who had 93 lesions dilated. Fibromuscular dysplasia was the cause of 30 stenoses in 27 patients. Seven patients had stenoses in the arteries to their renal transplants. Three patients had their saphenous bypass grafts dilated. One patient had his native artery dilated after his saphenous bypass graft occluded, and one patient had three stenoses due to previous irradiation therapy.

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Renin

Physiology

Kenovascular hypertension can be defined as hypertension caused by obstruction of the main renal artery or one of its branches. The difficulty in making the diagnosis of true renovascular hypertension only begins after identification of an anatomic obstruction. The temptation to dilate a renal artery stenosis, once it has been discovered, is great. This is enhanced by the fact that the absence of lateralization of the renins does not preclude a successful result following correction of the renal artery stenosis in 21% of patients.*15 However, in 1956, Smith pointed out that only 26% of patients having a nephrectomy for apparent unilateral renovascular hypertension were normotensive at the end of 1 year.lj6 Eyler et al1l7 studied the arteriograms of normotensive and hypertensive adults and found major renal artery stenoses in both groups. Holley et al.‘l’ demonstrated that renal artery stenosis was present at autopsy in 49% of patients who had been normotensive during life. Therefore, once a renal artery stenosis is identified in a hypertensive patient, the physiologic importance of the lesion should be assessed before correcting the lesion. If the physiologic significance of this lesion is not ascertained, optimal results will not be achieved with angioplasty.

for Renovascular

Indications

Workup

It has been generally accepted that it is not feasible to completely evaluate all hypertensive patients for renovascular disease. It is not cost-effective. The patients selected for study vary from one medical center to another; however, certain patients have an increased risk for renovascular hypertension. Patients who can be categorized in one of the following groups should be worked up for renovascular hypertension:

does not include response angiotensin system).

blockers

7. Patients with hypertension 8. Patients who while on captopril.

develop

of the renin-

and a flank bruit. renal

insufficiency

The workup of patients suspected of having renovascular hypertension varies with the institution. However, initially a peripheral blood sample may be drawn for renin analyses. If the renin level is elevated, renal vein samples are obtained. Selective samples are drawn from both renal veins and the inferior vena cava. This can be performed on an outpatient basis. An IV digital subtraction angiographic (DSA) study can be performed during the renal vein sampling. However, IV studies may miss subtle lesions caused by fibromuscular dysplasia or branch stenoses. Therefore, if the renin values are elevated and IV DSA is negative, an arteriogram should be obtained. Alternatively, in patients strongly suspected of having angiotensinogenic hypertension, renal vein renin sampling and arteriography can be performed on the same day. If the patient has impaired renal function, an intraarterial digital study can be performed with nonionic contrast material. Intraarterial digital studies are far superior to IV digital studies because they have increased resolution and conserve contrast material.

Indications

for

Renal

Angioplasty

2. Hypertensive patients without a family history of hypertension or other identifiable secondary causes of hypertension.

The indications for renal angioplasty include the correction of proved renovascular hypertension and the correction of the angiotensinogenic component in patients with essential hypertension and superimposed renovascular hypertension. Many of the patients in the University of Virginia series have a long history of hypertension with recent acceleration of blood pressure due to superimposed renal disease. In patients with deteriorating renal function, renal angioplasty may be indicated. If these patients have underlying renal artery stenoses, correction of these lesions may preserve or improve renal function.

3. Young women who develop and are not on birth control pills.

Techniques

I. Patients of hypertension.

with

a documented

sudden

hypertension

4. Patients who develop malignant sion, especially in the white population. 5. Patients who suddenly

with longstanding develop accelerated

onset

hyperten-

hypertension hypertension.

6. Patients who are refractory to drug therapy or who become refractory to drug therapy (this Curr

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for Renal

Angioplasty

Since the introduction of renal angioplasty by Grtintzig et al.“’ in 1978, the technique has been refined and simplified.108’11g Renal angioplasty, however, remains more complex than peripheral angioplasty. The procedure is far from innocuous and should be performed only by angiographers who have had considerable experience dilating pe117

ripheral vessels. Inflation of the balloon is simple, but successfully crossing a tight stenosis with a balloon catheter requires great skill, and selection of the proper-sized balloon requires experience. Martin et al1l4 found a significant increase in their primary success rate and a decrease in complications when comparing the results of their first 100 renal angioplasties with their second 100 angioplasties. A high-quality preliminary midstream arteriogram is necessary to evaluate patients prior to PTRA. In the presence of renal insufficiency, nonionic contrast material should be used. If an abdominal arteriogram has not been obtained within the previous month, a repeat arteriogram should always be obtained prior to selecting the renal arteries. This is important because profound changes may occur in a short period of time in the presence of a tight renal artery stenosis. The preliminary midstream arteriogram determines the approach to be used. There are five different percutaneous angiographic approaches that can be utilized to treat stenoses or occlusions in the renal arteries : 1. Femoral balloon catheter system-femoral approach. 2. Femoral balloon catheter system-axillary approach. 3. Femoral balloon catheter system-femoral sidewinder approach. 4. Guided coaxial balloon catheter system. 5. Kissing balloon technique. FEMORAL BALLOON CATHETER SYSTEMFEMORAL APPROACH This technique (Fig 44) uses a modification of the double-lumen balloon catheter designed by Griintzig for peripheral artery angioplasty. Only catheters with a tightly wrapped low-profile balloon located close to the tip of the catheter should be utilized in the renal arteries. In tight stenoses, it is important not to test inflate the balloon prior to inserting it. This facilitates passage of the balloon through the stenosis. The 7-F Griintzig-type balloon catheters are usually employed. These are available in 2, 3,4, 5, 6, 7, and 8 mm diameters and several balloon lengths, but the 2-cm-long balloon is usually employed in renal angioplasty. In pediatric cases, branch vessels, or in patients with small arteries, a 4.3-F or 5-F catheter system can be used. The femoral artery is punctured and the appropriate 5-F diagnostic catheter is advanced into the abdominal aorta using the Seldinger technique. The orifice of the renal artery is carefully selected, and contrast material is injected to localize the lesion. Under iluoroscopic guidance, a 0.035 long tapered tight J or a 0.035-inch Bentson 118

FIG 44. Technique of PTRA with the femoral balloon catheter system using the femoral approach. The renal artery is selected, and the guide wire is passed across the stenosis under fluoroscopic control. The diagnostic catheter is advanced through the stenosis. The diagnostic catheter is exchanged for the dilatation catheter over an exchange wire, and the lesion is dilated. (From Tegtmeyer CJ, SOS TA: The techniques of renal angioplasty. Radiology 1986; 161:577-586. Reproduced by permission.)

guide wire is advanced beyond the stenosis into the renal artery. When using a J guide wire, it is important to form the J tip before the wire is in contact with the lesion. If these guide wires will not pass the stenosis, the lesion can often be passed with a 15-mm J guide wire or 0.014- or 0.018-inch steerable wire. It is very important to avoid subintimal passage of the guide wire. Once the stenosis has been crossed, it is important to advance the 5-F selective catheter acmss the stenosis into the renal artery. This facilitates the subsequent passage of the balloon catheter. A small amount of contrast material is injected to ascertain the intraluminal position of the catheter. Once the catheter is acmss the lesion, 2,000-5,000 IU of heparin and 2.5 mg of verapamil are injected through the catheter. A 0.035-inch movable-core J wire or a 0.035~inch Rosen wire is then inserted through the catheter into the renal artery beyond the stenosis. The diameter of the J should be smaller than the vessel in which it is inserted. If this is not possible, a straight wire is used. The diagnostic catheter is then exchanged for the appropriately sized renal balloon catheter. The balloon size is chosen by measuring the renal artery proximal and distal to the stenosis (Fig 45). The original size of the renal artery in the stenotic area is estimated. If the renal artery is estimated to have measured 5 mm in diameter, this is the size of balloon that should be Curr

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FIG 45. Selecting the balloon catheter. The balloon correspond to the original diameter of the Poststenotic dilatation must be taken into renal arteries are magnified by 15%-20% grams, the arteries will be overdilated by (From Tegtmeyer CJ, Kellum CD, Ayers C: minal angioplasty of the renal artery: Results up. Radiology 1984; 153:77-84. Reproduced

catheter is selected to stenotic renal artery. accdunt. Because the on standard angioapproximately 1 mm. Percutaneous transluand long-term followby permission.)

used. This does not take into account the magnification factor, and poststenotic dilatation is discounted; therefore, the renal arteries are being slightly overdilated (approximately 1 mm). It is very important to avoid moving the guide wire back and forth in the branches of the renal artery when exchanging the catheters. This may induce spasm or cause occlusion of the segmental branches of the renal artery. If the balloon catheter will not cross the stenosis, a 5-F catheter with a 24-mm balloon is passed across the lesion over a 0.014- or 0.01%inch guide wire. These smaller balloons have a very low profile and are ideal for crossing tight resistant lesions. The balloon is inflated, partially dilating the stenosis. The proper-sized balloon catheter can then be easily advanced across the stenosis. The balloon catheter is positioned across the stenosis under fluoroscopic control, and the balloon is inflated either with a USC1 inflation device or with a syringe. The balloon is inflated first with 2 atm of pressure to determine the position of the balloon in relationship to the stenosis. After the balloon has been properly positioned, the balloon is inflated with 4-6 atm of pressure. The balloon is inflated for 30-60 seconds. It may be necessary to dilate the lesion several times. The progress of the dilatation can be monitored by watching the configuration of the balloon as it is inflated. The 0.035 inch wire is then exchanged for a 0.025-inch wire and Tuohy-Borst connector is used. The balloon is carefully pulled back over the 0.025-inch wire, and contrast material is injected to assess the results Cum

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of the angioplasty. With the use of a 0.025-inch wire, the balloon catheter can be readvanced if the lesion requires further dilatation. Immediately after mRA, arteriography is repeated with a pigtail catheter in the aorta to assess the results of the procedure. When removing the balloon catheter, it is important to completely deflate the balloon and apply suction to the balloon as it is being removed from the femoral artery. The primary advantage of this technique is that only a 5-F or 7-F puncture wound is necessary in the femoral artery. If the severity of the stenosis permits easy passage of the balloon, this is the simplest approach. However, if the stenosis is tight and/or the renal artery branches from the aorta at an acute angle, it is often difficult to make the balloon catheter follow the guide wire across the lesion. The balloon catheter has a tendency to buckle in the aorta when pressure has to be applied to traverse the stenosis from this approach. This difficulty may often be overcome by advancing first the 5-F diagnostic catheter, and then either a 7-F tapered Staple-van Andel or the 24-mm balloon as described above, then reinserting the balloon catheter. If these techniques do not work, the axillary or femoral sidewinder approach may be necessary. FEMORAL BALLOON CATHETER-AXILLARY APPROACH The axillary approach (Fig 46; see also Fig 11) may also be used to dilate the renal arteries.43 When the renal arteries originate from the aorta at a sharp caudal angle, the axillary approach greatly simplifies the procedure. The stenotic renal artery is easily selected by the axillary approach with either a multipurpose or cobra-shaped catheter. Once the guide wire is in place across the lesion, the dilatation catheter has a natural tendency to follow the gentle downward curve of the guide wire across the stenosis. Passage of the guide wire through the stenosis and the catheter across the stenosis is often facilitated by having the patient take a deep breath. The axillary approach is also useful when severe atherosclerotic disease or bypass grafts are present in the pelvic or abdominal vessels. The technique also uses the double-lumen balloon catheter designed by Griintzig for superficial femoral artery angioplasty. A left axillary approacir is usually utilized, because this is the straightest approach to the descending aorta. The balloon catheter has a tendency to buckle in the ascending aorta when the right axillary approach is attempted. The technique is similar to that used in the femoral approach. Theoretically, there is an increased risk of damage to the smaller axillary artery; however, this can 119

nosis followed by the catheter. Once the catheter is across the lesion, Z,OOO-5,000 IU of heparin and 2.5 mg of verapamil are injected through the catheter. The guide wire is exchanged for a movablecore J guide wire or a Rosen wire. The diagnostic catheter is then exchanged for the appropriately sized renal balloon catheter. After the sidewinder catheter has crossed the lesion, the balloon catheter will usually cross the stenosis with ease. The major advantage of this technique is that withdrawing the sidewinder catheter advances the diagnostic catheter across very tight stenoses because the configuration of the catheter exerts considerable downward force as the catheter is withdrawn over the guide wire. This technique is very helpful in traversing tight stenoses or complete occlusions. After balloon dilatation, a midstream arteriogram is obtained to document the results of the procedure. Fl6 46. Technique of PTRA, axillary approach. The renal artery is selected and the guide wire is gently advanced through the stenosis. The selected catheter is advanced across the lesion. The diagnostic catheter is exchanged for the balloon catheter. The balloon is inflated, dilating the lesion. (From Tegtmeyer CJ, SOS TA: The techniques of renal angioplasty. Radiology 1986; 161577-586. Reproduced by permission.)

GUIDED COAXIAL BALLOON CATHETER SYSTEM The Griintzig-type guided coaxial balloon catheter system (Fig 481 utilizes an 8-F or 9-F renal guiding catheter and a 4.3-F or 4.5-F coaxial balloon catheter. The renal guiding catheter is available in three configurations (Fig 49). The guiding catheter is inserted through the femoral approach, and the orifice of the renal artery is carefully selected. The

be minimized by deflating the balloon carefully and rotating it as it is being inserted and removed. There is also the possibility of brachial plexus injury; however, this possibility can be decreased by using the high brachial approach. The brachial artery is entered just distal to the axillary crease. The artery is easier to control in this area because it can be compressed against the humerus and any hematoma is less likely to injure the brachial plexus. FEMORAL BALLOON CATHETER SIDEWINDER APPROACH

SYSTBM-

The sidewinder approach (Fig 471 combines the advantages of the femoral and axillary approaches. This is the technique used in the majority of cases. The same 7-F Griintzig-type double-lumen balloon catheter employed in the femoral approach is used in the sidewinder approach. The larger femoral artery is punctured, but the renal artery is approached from above in order to take advantage of the natural curve of the renal artery, and it is selected with a 5-F “shepherd’s crook” catheter or a “sidewinder” catheter?1~‘2W122 The catheter is carefully advanced across the lesion under fluoroscopic control as contrast material is injected to keep the tip within the lumen of the artery; or a flexible-tip guide wire is advanced across the ste120

FIG 47. Technique of PTRA using a shepherd’s crook or sidewinder catheter. The orifice of the renal artery is selected, and the guide wire is passed across the lesion. The catheter is advanced across the stenosis by withdrawing the catheter at the puncture site. The catheter is exchanged for a balloon catheter, and the lesion is dilated. (From Tegtmeyer CJ, SOS TA: The techniques of renal angioplasty. Radiology 1986; 161577686. Reproduced by permission.) Curr

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FIG 48. Technique of PTRA with the coaxial balloon catheter system. The orifice of the renal artery is selected with the guiding catheter. The steerable wire is directed into the appropriate branch and across the stenosis. The balloon catheter is advanced across the stenosis, and the lesion is dilated. (From Tegtmeyer CJ, SOS TA: The techniques of renal angioplasty. Radiology 1986; 161577-586. Reproduced by permission.)

small coaxial catheter is then passed through the guiding catheter and across the stenosis. The balloon catheter will accept a 0.014- or 0.016-inch guide wire which can be passed across the stenosis prior to advancing the balloon catheter in the presence of a very tight stenosis. With the advent of the new platinum-tipped steerable wires, which are highly visible, this is a very effective technique. In the presence of a tortuous renal vessel, a tight stenosis, or a stenosis in a branch, the fine guide wire greatly facilitates passage of the balloon catheter. If the stenosis is not too tight, the coaxial catheter can be advanced across the stenosis without the guide wire as a small amount of contrast material is injected.

The advantage of this technique is that the fine coaxial balloon catheter passes through the tight stenosis more readily than the 7-F balloon catheter. It is also easy to steer this catheter out into the branches of the renal artery. Therefore, this catheter system is usually used in the renal arteries in the presence of a very tight stenosis which cannot be passed by other techniques, or in the treatment of distal or branch stenoses. There are several disadvantages to the technique. The catheters are expensive, and it is necessary to make an 8-F or 9-F puncture wound in the femoral artery. The guiding catheter is stiff and may damage the aortic wall. The guiding catheter is inserted over a 0.063inch guide wire, which is also quite stiff and may traumatize the aortic wall. Balloon sizes are available from 2 to 4.2 mm. However, if an 8-F guiding system is used, the balloon catheter is limited to less than 3 mm. The technique is also more complex than with the standard femoral balloon catheter approach. The common femoral artery is punctured and a two-part sheath is introduced over a 0.038-inch guide wire. The sheath is advanced into the distal abdominal aorta. Once the sheath is in place, the inner cannula is removed and the 0.063-inch guide wire is advanced into the abdominal aorta to the level of the diaphragm. The guiding catheter is then advanced over the guide wire through the sheath and into the abdominal aorta. The guide wire is removed, and the guiding catheter is used to select the renal artery orifice. The balloon catheter is then advanced through the guiding catheter and across the stenosis. The small diameter of the balloon makes it possible to obtain pressures across the stenosis. The balloon is then inflated with a mixture of one-half contrast material and one-half normal saline. During inflation, the progress of the angioplasty can be monitored by injecting contrast material either through the balloon catheter or through the guiding catheter. This is a definite advantage. However, caution should

FIG 49. The renal guiding catheter is available in three basic configurations. The choice of the guiding catheter depends on the size of the aorta and the angle that the renal artery takes as it branches from the aorta. (From Tegtmeyer CJ: Renal angioplasty. Intervention 1984; 1:215. Reproduced by permission.)

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121

be exercised when injecting contrast material the area of the dilatation, because of the injury the intima caused by the dilatation procedure.

in to

KISSING BALLOON TECHNIQUE This technique, which was originally described for dilating lesions at the bifurcation of the abdominal aorta,36’ 37 has application in selected cases in the renal arteries.123 If two renal arteries originate from the aorta in close proximity or if the lesion involves a major bifurcation in the renal artery (Fig 50,AA),dilating the lesion may occlude the adjacent vessel. In this situation, catheters are inserted through both femoral arteries, and a catheter is passed across one artery to protect it while the lesion is dilated over a guide wire passed across the lesion and into the involved branch (Fig 50,B). The origin of the uninvolved branch is usually protected by the diagnostic catheter (Fig 50,C). If the origin of the vessel is involved by the lesion or compromised by the procedure, the catheter is exchanged for a second balloon catheter, and the lesion is dilated.

Treatment

and Prevention

of Vascular Spasm

Spasm of the main renal artery or of a major arterial branch is a frequent occurrence during renal

angioplasty.lM This is usually caused by mechanical stimulation of the vessel wall by the guide wire or catheter and may occur locally or at a distance. If possible, the guide wire should not be placed within the segmental branches of the renal artery (Fig 51). Focal spasm may also be produyd in the area adjacent to the angioplasty site or even in distal small branches. Calcium channel blockers are highly effective in preventing and reversing spasm in the renal arteries. At the University of Virginia, we have been prophylactically giving the patients 2.5 mg of verapamil intraarterially through the diagnostic catheter as soon as the lesion is crossed. If spasm is encountered, another 2.5 mg of intraarterial verapamil is given. During the 3% years we have used this technique, there has been a marked decrease in the number of patients experiencing spasm during FTBA. If spasm occurs in spite of the calcium channel blockers, intra-arterial nitroglycerin in a dose of 100-200 p,g is given. Nitroglycerin is very effective in relieving spasm, but its mechanism of action is different from that of the calcium channel antagonists. It has an additive effect when given with the calcium channel blockers, so it is very effective when spasm is encountered after the blocker has previously been administered. We prefer to use the calcium channel blockers initially because the duration of action is longer than that of

FIG 50. Kissing balloon technique in the renal arteries. The 28-yearold woman presented with a 2-year history of hypertension. A, midstream arteriogram demonstrates a tight stenosis at the junction of the dorsal and ventral branches of the renal artery. B, loo-mm spot radiograph shows the balloon inflated in the upper branch, dilating the lesion, and a catheter in the lower artery protecting the orifice of the artery. C, immediately after PTRA, the renal artery and both branches are widely patent. (From Tegtmeyer CJ, SOS TA: The techniques of renal angioplasty. Radiology 1986; 161577-586. Reproduced by permission.)

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FIG 51. Renal parenchymal defect caused by a guide wire during PTA. A, selective renal arteriogram reveals changes consistent with fibromuscular dysplasia (arrow). B, immediately after dilatation, the angiogram demonstrates a defect in the lower pole of the kidney (arrow) caused by the guide wire, which is still in place in the segmental branch. C, arteriogram taken 3 months later shows res-

olution of the defect. The renal arteries Tegtmeyer CJ, Teates CD, Crigler N, et minal angioplasty in patients with renal studies. Radiology 1981; 140:323330. sion.)

nitroglycerin. Verapamil is the only calcium channel blocker available in a liquid parenteral form. Nifedipine, on the other hand, is the most potent vasodilator of the calcium channel blockers available. Calcium channel blockers may induce hypotension, and they should be used with caution in patients who have known cardiac conduction defects. It is also important to remember that the guide wire is the major cause of spasm, and that continued stimulation of the vessel wall will cause spasm to recur. All catheter and guide wire manipulations should be kept to a minimum. The most effective treatment of spasm is to remove the catheter and guide wire.

drop in the blood pressure. If the diastolic pressure rises above 110 mm Hg, the blood pressure should be controlled by captopril or with shortacting antihypertensive drugs. A drop in blood pressure can usually be controlled by the rapid IV infusion of normal saline. Therefore, all patients undergoing renal angioplasty should have an IV line in place prior to the procedure. If not contraindicated, the patient receives 2,000 IU of heparin subcutaneously every 6 hours. The heparin is begun 8 hours after the procedure and continued for 2 days. The patients also receive 75 mg of Persantine orally twice a day and 325 mg of aspirin once a day, beginning the day prior to angioplasty and continued for at least 6 months. The patients are encouraged to stop smoking. After angioplasty, the patient should be followed by a hypertensionologist, either a cardiologist or a nephrologist, who specializes in the control of high blood pressures. The specialist should participate in the selection of patients for renal angioplasty and should follow the patients after they are dilated. The patient’s blood pressure medication needs to be adjusted after the procedure, and the blood pressure must be followed closely. If the blood pressure rises in the ensuing months, repeat arteriography or DSA should be performed.

Patient Management Proper management of candidates for renal angioplasty requires a team approach. The proper selection of patients and the management of the blood pressure requires the close cooperation of a hypertension specialist. Inadvertent occlusion of the renal artery may create a surgical emergency. Therefore, the procedure should only be performed when a skilled vascular surgeon is available. The blood pressure must be monitored very carefully during the procedure and for the first 2448 hours after angioplasty because profound changes may occur. It is important to discontinue the antihypertensive medications prior to renal angioplasty, which will help prevent a precipitous Curr

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are widely patent, (From al: Percutaneous transluartery stenosis: Follow-up Reproduced by permis-

Results In experienced hands, renal angioplasty is a highly effective method for correcting renal artery 123

lesions. An initial success rate greater than 90% should be achieved when dilating renal artery stenoses (Table 3). Technical failures usually result from an inability to cross the lesion, or failure of the balloon to adequately dilate the lesion. The long-term results of renal angioplasty can be assessed in three ways: the effect of the procedure on vessel patency, the effect of angioplasty on the blood pressure, and the effect of angioplasty on renal function. The effect of the procedure on vessel patency is related to the etiology of the lesion and the characteristics of the lesion. The patients can be divided into five distinct groups: 1. Patients with atherosclerotic renal artery stenoses or occlusions. 2. Those with fibromuscular dysplasia of the renal artery. 3. Those with transplants. 4. Patients with saphenous bypass grafts. 5. Those dilated primarily for renal insufficiency. ATHEROSCLEROTIC LESIONS Atherosclerotic disease is the most frequent cause of stenosis treated by renal dilatation. In the University of Virginia series, 94% of the 65 hypertensive patients with atherosclerotic lesions were helped by the procedure. Of these patients, 23% were cured and 71% were improved after PIRA. Analysis of the results in the patients with atherosclerotic lesions revealed several other factors that are important when selecting patients for angioplasty. Better results are achieved in patients with unilateral renal artery stenoses than in patients with bilateral renal artery stenoses. The restenosis rate is higher in patients with severe bilateral renal artery disease than in patients with unilateral renal artery stenosis.31 SOS et al.‘l’ and Martin and associates113 also showed that success was more frequent in patients with unilateral lesions than in patients with bilateral disease. Furthermore, it is

Katzen

et al.,‘o3 1979

Puijlaert et EII.,‘~ 1981 Schwarten,lm 1981 C&pinto et al.,“’ 1982 SOS et al.,‘o7 1982 Tegtmeyer et al..= 1984 Martin et al..“’ 1986

‘Includes

124

successful

mxlilatations

94% lesions 96% 93% lesions 85% 79% 95% 88%

75% lesions 70% 71%

79%-95X

70%-90%

lYr

6 mo.

81%

3yr

93% * 70%

5yr 3yr

‘h-6 yr

becoming increasingly clear that certain lesions are more amenable to balloon dilatation than others. A good result can be anticipated in short isolated atherosclerotic lesions (Fig 52); however, when the renal artery stenosis is caused by a large plaque in the abdominal aorta that engulfs the origin of the renal artery, chances of success are diminished. Figure 53 illustrates the type of lesion in which this diminished response is often obtained. Cicuto et al.?% SOS et al.,“’ and Schwa.rtenlz6 all reported similar results. In the University of Virginia series, one third of the redilated lesions were due to lesions caused by aortic plaques that engulfed the origin of the renal artery. These lesions can be dilated and in some cases (Fig 54) dramatic results are obtained, especially now that highpressure balloons are available. However, often the artery is improved (Fig 551, but a large residual stenosis (>30%) remains. Complete blocks are more difficult to dilate than renal artery stenoses, and it is clear that complete blocks that are not perfectly straight should not be attempted. Also, recanalization should be attempted only if the renal artery proximal and distal to the occlusion is clearly identified, and the size of the kidney warrants salvage.31,127 FIBROMUSCULAR DYSPLASIA The best results in renal angioplasty are achieved in patients with fibromuscular lesions (Fig 56). Fibromuscular lesions respond well to balloon dilatation, usually at pressures of 4 atm or less. If the lesion can be crossed, a good result can be anticipated.z4’ X, 31 There were 31 hypertensive patients with 37 lesions due to fibromuscular dysplasia in our seriesf6 All of the patients benefited from renal angioplasty. Only one patient with fibromuscular dysplasia required repeat dilatation. Similar results have been achieved in several other series. Geyskes et al.“’ dilated 21 patients for fibromuscular dysplasia, and 95% of them were cured or improved. There was only one failure. SOS et al.l12 achieved a technical success when dilating lesions due to fibromuscular dysplasia in 27 of 31 patients. STENOSES IN RENAL TRANSPLANTS Renal transplant arteries are anastomosed either directly end-to-end to the hypogastric artery or end-to-side to the external iliac arteries. Stenoses may be proximal to, at, or distal to the anastomosis. Proximal stenoses in the hypogastric arteries are usually atherosclerotic in origin, and they respond well to PTRA. Anastomotic stenoses are largely due to surgical technique, perfusion injury, or local reaction to the suture material. Hypogastric anastomoses are best approached with a retrograde contralateral femoral artery puncture and Curr

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FIG 52. Long-term results of angioplasty in an atherosclerotic lesion are illustrated in a 60-year-old man with a solitary kidney and hypertension. A, selective arteriogram reveals a tight stenosis (arrow) in the renal artery. B, loo-mm spot radiograph shows the 5mm balloon in place. C, immediately after PTA, the stenosis ablated (arrow). D, repeat arteriogram, obtained 3 months after PTA, demonstrates the

widely patent vessel. E, repeat arteriogram, obtained 4% years after angioplasty, shows the continued patency of the artery. (From Tegtmeyer CJ, Dyer R, Teates CD, et al: Percutaneous transluminal dilatation of the renal arteries: Techniques and results. Radiology 1980; 135589-599. Reproduced by permission.)

around the aortic bifurcation or from the axilla. End-to-side external iliac to transplant renal artery anastomoses, on the other hand, are best approached from the retrograde ipsilateral femoral artery. High-pressure balloons are frequently necessary to dilate these lesions. Stenoses at end-toside anastomoses are usually focal elastic fibrotic bands and often require multiple vigorous intlations to achieve a permanent dilatation. Distal stenosis is common and may result from altered hemodynamics, vessel trauma, immunologic factors, and arterial kinking or extrinsic compression. Arterial kinking does not respond to dilatation as readily as intimal hyperplasia, which is often seen in this area. There were seven patients with stenoses in the arteries with renal transplants (Fig 57) who underwent dilatation in the University of Virginia series.26 Five patients were improved, and there were two failures. One of these failures was due to inability to dilate the lesion initially, and this was probably due to the use of a polyvinyl chloride balloon. Now that polyethylene balloons are available, a better result would probably have been achieved in this patient. In another patient, a tight stenosis at the anastomosis of the transplant to the hypogastric artery failed after 7 months despite three attempts

at dilatation. Pressures as high as 14 atm were utilized. Sniderman et al.‘28 attempted to dilate 15 patients with stenoses in the arteries to their renal transplants. Three patients underwent repeat dilatations. The procedure was technically successful in 15 of the 18 attempts and in 13 of the 15 patients. Gerlock et al.‘2g successfully dilated all seven patients with renal transplant stenoses in their series. Caution should be exercised when dilating lesions in patients with renal transplants because there are no collateral vessels to the kidney. If the vessel is occluded, surgery must be undertaken immediately. Therefore, in cases of renal transplant dilatation, a surgeon should be readily available.

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STENOSES IN SAPHENOUS BYPASS GRAFTS In the University of Virginia series,31 three patients undenvent dilation of stenoses in their renal saphenous bypass grafts. The lesions were successfully dilated in all three cases. Renal Insujjkiency Under certain circumstances, alleviation of renal artery stenosis is important to preserve renal function. It is clear that renal function can be pre126

FIG 53. The type of atherosclerotic lesion in which a diminished response to balloon dilatation can be anticipated. Left, lesion is caused by atherosclerotic plaque in abdominal aorta that engulfs orifice of the renal artery. Occasionally a good result is obtained, but usually results are poor when compared with results in other types of le-

sions. Right, a good response can be anticipated in short stenoses within the renal artery. (From Tegtmeyer CJ, Kofler TJ, Ayers CA: Renal angioplasty: Current status. AJR 1984; 142:17-21. Reproduced by permission.)

served if the renal artery stenosis is corrected. This is probably worthwhile in unilateral renal disease if the kidney size indicates potentially significant preservation of renal mass or if bilateral renal artery stenoses are present. In the latter case an attempt to alleviate obstruction to the largest kidney should be given priority even though the small kidney is secreting all the renin. The results are not as dramatic following angioplasty in patients treated primarily for renal insufficiency as in patients treated primarily for hypertension. The results, however, are encouraging. In our series,31 ten patients were treated primarily for renal insufficiency. They all had atherosclerotic lesions. The mean serum creatinine level was 5.2 mgkll before dilatation, and after PTRA this decreased to 2.3 mgkll for the group. Five of the patients had a positive response to dilatation, and five have not been helped. Twenty-nine of the patients treated primarily for hypertension also had accompanying renal insufficiency. Nine of these patients had improved renal function following the procedure, and four have normal BUN and cmatinine values. In some of the patients, the improvement was gradual after angioplasty, and the full benefit of the procedure was not apparent for several months.

pressure response has been analyzed in the 92 hypertensive patients whose initial dilatation was successful.31 The patients have been followed up from 1 to 60 months (mean, 23.7 months; median, 23.0 months). The mean systolic pressure was 199.74 mm Hg before renal angioplasty and 140.4 mm Hg after angioplasty, a difference of 59.40 mm Hg; the mean diastolic pressure was 117.05 mm Hg before renal angioplasty and 93.74 mm Hg afterward, a difference of 33.31 mm Hg. Analysis of the long-term clinical results in the 98 hypertensive patients who underwent renal angioplasty to control their blood pressure reveals that 26% were classified as cured (defined by the Cooperative Study of Renovascular Hypertension13’ as having an average diastolic pressure of less than or equal to 90 mm Hg with at least a 10 mm Hg decrease from the predilatation level). There were 67% classified as improved, and their blood pressure was easier to control on medication as a result of the angioplasty procedure. Only 7% of the patients were nonresponders, although one was helped for several months. A review of several large series in the world literature (see Table 3) shows that if the initial dilatation is successful, the vessels can be expected to remain patent in 70%~90% of the patients. If the vessel remains patent for at least 8 months, it is likely to remain patent for at least 5 years. The recurrence rate after PTRA has been variously reported as being between 12.9%31 and 22.5%.lz6 The recurrence rate is clearly higher in atherosclerotic stenoses than in other types of

Summary

of Results

Renal angioplasty is a clinically effective means of treating renovascular hypertension. The blood 1243

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stenoses. A major factor in determining the recurrence rate is the success of the initial dilatation. Lesions that exhibit 30% or greater residual stenosis on the immediate post dilatation films are more likely to recur than lesions in which a better result has been obtained.2g’3* Therefore, it is essential that a good initial result be obtained. Restenoses, however, are usually successfully redilated, and the procedure is often easier than the initial procedure. BRACHIOCEPHALIC

ANGIOPLASTY

There is great reluctance to use PTA for the treatment of lesions in the brachiocephalic vessels because of the potential complications associated with distal embolization an&or occlusion of the vessel being dilated. At present, there is no reliable technique available for preventing distal embolization. Therefore, angioplasty in this area has to be approached with caution and only by angiographers with extensive experience in dilatation of other vessels. Symptomatic stenoses in the subclavian vessels have been successfully treatedwith angioplasty?31-133 In the subclavian vessels with an already occluded Cur-r

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vertebral artery, the risk is minimized (Fig 58). Theoretically, in patients with a subclavian steal, the flow in the vertebral artery is reversed. This should protect these patients from embolization to the brain until the lesion is corrected. The femoral approach is utilized, if possible, because large balloons, size B-10 mm, are necessary to adequately dilate these vessels. The origin of the artery is selected with a 5-F catheter, if possible, and a Bentson wire is advanced across the stenosis, followed by the diagnostic catheter. A 240- or 260-cm Rosen wire is advanced into the axillary artery, and the catheter is exchanged for the appropriate-sized balloon. The procedure is the same as for other vessels except that it should be performed quickly. It is important to localize the stenosis fluoroscopically and to precisely localize the lesion by a bony landmark or with a metal marker on the skin. The balloon size should be chosen very carefully by measuring the artery, as described previously. Once the balloon has been inflated to dilate the lesion, the advantage of reversed flow in the vertebral artery will be lost. The risk is increased if the lesion is underdilated and a larger balloon is needed. The distance from the femoral puncture to the dilatation site is long and many of the ves127

FIG 55. Diminished response in renal artery orifice lesions caused by plaques in abdominal aorta in 68-year-old woman with long standing hypertension. Note very tight stenosis at origin of left renal artery and 60% stenosis in right renal artery. A, predilatation aortogram. Tight stenosis at origin of left renal artery (arrow). B, loo-mm spot radiograph shows 6-mm balloon in place. (Note that balloon is not completely expanded.) C, immediately after PTA, artery is improved but residual stenosis remains. (From Tegtmeyer CJ, Kofler TJ. Ayers CA: Renal angioplasty: Current status. AJR 1984; 142: 17-21. Reproduced by permission.)

sels are tortuous. This makes it difficult to hold the balloon in the proper position during dilatation. The balloon has a tendency to slide off the lesion during inflation. Therefore, the guide wire should be kept in place during the dilatation. If the length of the vessel permits the use of balloons 3 or 4 cm long, this will also reduce the tendency of the balloon to slide off the lesion. If possible, avoid placing the balloon across the origin of the vertebral artery. If the subclavian stenosis is located at the level of the origin of the vertebral artery, angioplasty is extremely hazardous and should be avoided. Motarjeme et al.13’ used angioplasty to treat 23 subclavian arteries in 22 patients with subclavian steal syndrome. They were successful in 15 stenoses and failed to dilate 6 total occlusions. No complications directly related to the procedure were experienced. Vitek et al.133 successfully dilated 13 subclavian stenoses. Angioplasty has also been used to treat a few selected atherosclerotic, nonulcerated stenoses in the vertebral artery,‘33’134 external carotid arcarotid artery,134 and innomiteTJ133p134 common nate artery.133 The treatment of fibromuscular disease in the carotids is promising. The internal carotid artery is the second most common location of fibromgscular disease? although the incidence is believed to 128

be less than 1% in patients undergoing carotid arteriography.136 About one half of these patients have associated renal artery stenosis caused by fibromuscular disease?37 Carotid fibromuscular disease is not a benign lesion, and serious neurologic sequelae are common in symptomatic patients. For example, the condition may cause transient or prolonged ischemic attacks, amaurosis fugax, completed stroke, a bruit audible to the patient, or nonlocalized neurologic symptoms. Surgical intervention, including endarterectomy or graduated intraluminal dilation, has been the treatment for patients with symptomatic lesions. In 1968, Morris and associatesl= reported the effectiveness of intraoperative progressive internal dilatation with bile duct dilators. They treated 12 cases of carotid artery fibromuscular disease, with success up to 4 years after the procedure. Effeney et al.136 dilated 118 lesions in 79 patients using intraoperative graduated metal dilators. During the early postoperative period, eight patients experienced a single episode of transient ischemia or amaurosis fugax. Three other patients suffered neurologic deficits that resolved within 30 days. Serious neurologic complications occurred in six patients during a follow-up period of 6 months to 14 years: two recurrences of generalized neurologic symptoms, two subarachnoid hemorrhages, Curr

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FIG 56. Long-term results of renal angioplasty in fibromuscular dysplasia are illustrated in a U-year-old woman with hypertension. A, renal arteriogram reveals extensive fibromuscular dysplasia of the right renal artery. B, immediately after dilatation with a 5-mm balloon, the vessel appears irregular but there is good flow through it. This appearance is typical immediately after PTA of fibromuscular dysplasia. C, arteriogram obtained 12% months later shows no evidence of the former lesion. This is the usual long-term appearance after dilatation of fibromuscular lesions. (From Tegtmeyer CJ, Kellum CD, Ayers C: Percutaneous transluminal angioplasty of the renal artery: Results and long-term follow-up. Radiology 1984; 153:77-84. Reproduced by permission.)

and two completed strokes. A nonneurologic complication was an instance of internal carotid perforation. Postoperative arteriography at 5 years demonstrated the durability of the repair in most cases, and the majority of patients were free of neurologic symptoms. Calvin discussed his use of the Grtintzig balloon catheter through a surgical approach instead of a rigid metal dilator in the treatment of fibromuscular disease in the internal carotid artery.136 Garrido and MontoyaJ3’ used a 7-F double-lumen Grimtzig balloon catheter to treat a similar case through a carotid arteriotomy. Six cases of internal carotid artery fibromuscular disease treated successfully by angioplasty have been reported.‘37’ ‘40-l~~ No complications were associated with these cases. Mullan et al.140 used the Griintzig balloon catheter to treat a 95-year-old woman. In 1981, Hasso et al.13’ reported one of the first series of patients, two of the three being treated with a 7-F Griintzig balloon dilating catheter. Dublin et al.14’ and Belan et al.142 each reported a single case. Dublin et al.141 projected that angioplasty of fibromuscular disease lesions in the carotid artery will have long-term successes similar to those of renal angioplasty. Thus, although the numbers are small in comparison with angioplasty performed in the renal arteries, the preliminary reports of carotid angioplasty are encouraging. The indication for vertebral or carotid angioCurr

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plasty is to improve blood flow to the central nervous system. Before angioplasty is attempted, a complete examination of the entire vascular tree should be undertaken. Because of the potential risks of the procedure, the indications must be well established. If surgery carries a lower risk than angioplasty, surgery should be performed. Angioplasty in this area is still in its infancy; however, improved techniques will be developed to allow safe, reliable treatment of lesions in these vessels with the balloon catheter. POSTOPEBATIVE ANGIOPIASTY

AND

BYPASS GBAFT

Recurrent symptoms after vascular surgery indicate either a progression of the original disease or that stenoses have developed in the graft or at the anastomoses of the graft. If a vein graft has been inserted, lesions can occur in the graft, often at the valve sites. Angioplasty is the best method for correcting postoperative strictures because repeat surgery is much more difficult than the original surgery. Stenoses also occur at the anastomoses of the grafts (Fig 59) due to intimal proliferation and fibrotic scar formation. The technique is similar to the techniques used in native vessel lesions. If possible, an ipsilateral approach is used. However, the 123

dertaken without first acquiring the knowledge and skills necessary to perform it. It is easier to stay out of trouble than to get out of trouble. Angioplasty is an invasive procedure, and there are no invasive medical procedures that can be performed without the risk of complications. A review of the literature reveals that complications can be expected in 9.5%-18.8% of patients.s0,145-145 Most of these complications are minor and resolve with conservative therapy. However, surgical management will be required in 2%~3% of cases. The complications can occur at the puncture site, angioplasty site, or distal to the procedure, or they may be systemic in nature. They may be related to failures in technique or to failure of the balloon catheter (Table 4). Puncture

FIG 57. PTA of stenosis in transplant artery in 23-year-old woman. A, selective arteriogram demonstrates a severe stenosis (arrow) in vicinity of anastomosis in the artery supplying the renal transplant. B, vessel is widely patent after balloon dilatation from the axillary approach. (From Tegtmeyer CJ, Brown J, Ayers CA, et al: Percutaneous transluminal angioplasty for the treatment of renovascular hypertension. JAMA 1981; 246:2068-2070. Copyright 0 American Medical Association, 1981, Reproduced by permission.)

graft itself should not be punctured, if a satisfactory alternative route is available. Therefore, either the axillary approach or the contralateral approach is often employed. Vein grafts can be punctured safely, but direct puncture of the graft should be avoided if possible. If it is necessary to puncture a synthetic graft, the puncture site should be dilated with graduated dilators before the balloon is inserted, and a sheath should be used. If a sheath is not used, it may be very difficult to remove the balloon catheter after the procedure, and the tip of the catheter may be broken off. Manipulations within the graft should be kept to a minimum because the pseudointima of the graft is very friable. COMPLICATIONS

During the past two decades, angioplasty has become an accepted and widely utilized procedure. However, it is important to remember that PIA is a specialized procedure that requires skill and experience. The procedure should not be un130

Site Complications

Complications at the puncture site are the most common complications. The most frequent complication is a hematoma, which occurs in 4% of patients.‘35 Obesity and hypertension are major predisposing factors. The frequency of this complication is also related to multiple attempts to enter the artery, the size of the balloon catheter, and the “wings” on the deflated balloon. The use of anticoagulants during the procedure further complicates the problem. The incidence of significant hematomas may be minimized by taking certain precautions. The balloon should be tightly wrapped around the catheter before it is inserted. The balloon should be deflated before it is removed, and the catheter should be rotated as the TABLE Potential

4. Complications

of Angioplasty

Puncture site Bleeding Thrombosis False aneurysm Nerve injury ki&wy) Angioplasty site Perforation Rupture Subintimal dissection Thrombosis Occlusion of adjacent vessels Spasm Distal Embolization Spasm Segmental infarction (renal) Other Renal insufficiency (contrast material) Hypotension kenal) Hemorrhage Contrast reactions Balloon malfunction Curr

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catheter is withdrawn, to rewrap the balloon. If the balloon is wrapped in a counterclockwise direction, the catheter should be rotated clockwise during removal. Since we decreased the amount of heparin used during the procedure, the frequency of this complication, in our experience, has diminished. If the procedure can be performed quickly (within 30 minutes) we now administer only 2,000 IU of heparin (vide supra). Careful compression is very important after angioplasty. The pulse should be compressed manually and enough pressure should be applied to stop the bleeding, but the pulse should not be obliterated. The vessel should be compressed for 20-30 minutes. Doppler monitoring should be performed during the compression, especially after angioplasty in the extremities. If the blood flow is completely cut off during compression of the puncture site, the puncture site or the angioplasty site may thrombose. It is important to avoid puncturing the femoral artery above the inguinal ligament. A high puncture above the ligament cannot be adequately Curr

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compressed after the catheter is withdrawn. This, coupled with the anticoagulation during the procedure, may result in severe bleeding. Since the patients bleed into the retroperitoneal space, not the groin, the bleeding may be undetected (Fig 60). A high index of suspicion must be entertained in a patient who develops unexplained tachycardia and hypotension following angioplasty. A plain Iilm of the abdomen or a CT scan will make the diagnosis. A large hematoma in the groin or axilla may result in a pseudoaneurysm. This is a very infrequent complication. A hematoma in the axilla may result in an injury to the brachial plexus. For this reason, a high brachial approach is utilized. This allows the puncture site to be compressed against the humerus, and if a hematoma develops, it will be less likely to compress the nerves. Angioplasty

Site Complications

The most important complication occurring at the angioplasty site is acute occlusion of the ves131

Angioplasty of strictures in a bypass graft. The 56-year-old man developed severe claudication 3 years after he received an aortobifemoral graft. A, midstream arteriogram reveals a stricture (arrow) at the proximal anastomoses of the graft. B, loo-mm spot radiograph shows the IO-mm, 4-cm-high pressure balloon in place, dilating the lesion. C, immediately following PTA, the lesion

is widely patent. D, the femoral arteriogram demonstrates a stricture (arrow) at the anastomosis of the right limb of the graft to the profunda femoris artery. E, 6-mm, 4-cm balloon is seen dilating the lesion. F, immediately following angioplasty, there is good flow across the lesion.

sel. Occlusion of the vessel may be due to subintimal dilatation, intimal flaps, spasm, or thrombosis. Subintimal dissection with the guide wire or the diagnostic catheter may result when attempting to cross the lesion. Further, subintimal dilatations will usually close off in the first 46 hours. Therefore, it is essential to cross the lesion under fluoroscopic control and as atraumatically as possible. The incidence of this complication is directly related to the experience of the angiographer.1’4’145 If

the guide wire is passed subintimally, the procedure should be postponed for 4-6 weeks. Alternatively, if subintimal dissection occurs during an iliac dilatation, the procedure may be attempted from another approach, i.e., from the contralateral or axillary approach. If the subintimal dissection results in occlusion of the vessel, the problem may have to be corrected by surgery if the occlusion is not tolerated by the patient. However, the surgery to correct the problem will usually be the same the

132

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patient would have undergone if angioplasty had not been attempted. Intimal flaps may be created by attempts to cross the lesion with the guide wire or by inflation of the angioplasty balloon. Crossing the lesion is the most critical step in angioplasty. It is very important to cross the lesion through the center of the remaining lumen parallel to its axis. Otherwise, the guide wire may damage the intima. If a flap is created crossing the lesion, the procedure should be postponed. The flap will usually heal in 4-6 weeks if the vessel is not occluded. Rarely, the angioplasty balloon may create a split in the intima that creates a flap occluding the lumen. In this situation, if a guide wire has been left across the lesion, a smaller balloon can be inserted and inflated. This will often tack the flap back, reopening the vessel. Vascular spasm is a major problem during anCurr

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gioplasty of the popliteal, brachiocephalic and renal vessels. Spasm is usually caused by mechanical stimulation of the vessel wall (see Fig 51). Focal spasm may also be produced in the area adjacent to the angioplasty site, or in the distal small branch vessels. Careful technique, calcium channel blockers, and nitroglycerin are used to prevent and relieve spasm. Lidocaine and the use of nonionic contrast material may also decrease the incidence of spasm. During dilatation of the renal and popliteal vessels, it is important to avoid placing the guide wire in the branch vessels, unless it is absolutely necessary. If the wire enters the segmental renal vessels or the popliteal branches inadvertently, spasm or an intimal flap may be produced. Forceful injection of contrast material across a recently dilated lesion may also occlude the vessel by producing an intimal flap. Thrombosis may occur at the dilatation site. 133

Gardiner et all* noted thromboses with resultant occlusion of the vessel in 2% of 453 dilatations. It is very important to ascertain immediately if the vessel has occluded. If the vessel has occluded due to thrombosis, it may be successfully treated by inn-a-arterial thrombolytic agents.75-78*145 If the limb or organ cannot tolerate the prolonged ischemia necessary for thrombolytic lysis, the location of the occlusion should be documented angiographically before the catheter is removed. The patient should then undergo immediate surgical revascularization. Rarely, the vessel may be ruptured by the balloon catheter. This occurred in 0.4% of Gardiner’s cases and scattered reports have appeared in the literature.3l’ 73,146,14’ If this complication occurs in a renal artery, rupture can be suspected when persistent flank and abdominal pain are present after the balloon is deflated. Temporary discomfort or pain during inflation of the balloon is normal, but the pain should not persist. Injection of contrast material may show either frank extravasation or an extravascular tract. The bleeding can be controlled by reinflating the balloon, sealing the rupture site. The patient is then taken to surgery, and the balloon is deflated when proximal and distal control of the artery is achieved. The vessel distal to the balloon can be partially perfused through the catheter while it is inflated. Perforation of the vessels usually occurs when one attempts to cross the lesion with the guide wire. If this occurs, the procedure should be terminated and the small puncture will seal. This is usually a minor complication, if persistent attempts are not made to recross the lesion. A small hematoma adjacent to the lesion is usually not a problem unless it extends into the trifurcation vessels and compromises a major collateral vessel to the lower leg. Care should be taken to protect major vessels and collaterals near the angioplasty site. If these vessels cannot be protected, angioplasty should not be attempted. Distal Complications Distal

embolization occurs in up to 5% of SO,80 In most patients it is of no clinical significance. However, a few cases will require surgical embolectomy. Embolization may result from the lesion being dilated or from thrombus originating on the catheter or from the puncture site. Care should be taken to avoid dilating fresh thrombus. If the lesion appears to be due to an acute thrombus or embolus, angioplasty should be avoided, unless the patient is first treated with thrombolysis. Patients with blue-toe syndrome are

cases.52,53,59,

134

not good candidates for angioplasty because of the possibility of distal embolization at the time of the procedure and continued recurrent embolization from the ulcerated plaque after the procedure. Spasm in the distal vessels usually results from mechanical stimulation of the vessel wall, and this has been discussed. Occasionally, in the popliteal and trifurcation vessels, spasm may result from the pain caused by the contrast material. This can be minimized by using nonionic contrast material mixed with lidocaine. Other Complications Transient renal insufiiciency is a frequent complication following renal angioplasty in patients with impaired renal function. It is usually caused by the contrast material. Transient renal insufflciency occurred in 6 of our first 109 renal angiocan be miniplasty patients.31 This complication mized by keeping the patient well hydrated. The procedure should be performed with the least amount of contrast material possible. Intraarterial digital imaging greatly decreases the contrast load, and in severely impaired patients the diagnostic arteriography and the angioplasty procedure can be performed several days apart. An infusion of 25% mannitol, begun before the procedure, may also help protect renal function. The incidence of balloon rupture has been greatly reduced by the development of new and improved balloons. A ruptured balloon may result in severe damage to the arterial wall and false aneurysm formation or occlusion of the vessel. Therefore, inflation of the balloon should always be monitored by a pressure gauge, and the safe pressure limits of the balloon should be observed. Repeated inflation of the balloon weakens the balloon, and it may then rupture. The polyethylene balloons usually rupture with a longitudinal split, and they are easily removed from the puncture site. Polyvinyl chloride balloons usually rupture they may split horizontally. vertically; however, Mylar balloons infrequently rupture, but when they do, it may be with a horizontal split. A horizontal rupture makes it difficult to remove the balloon through the puncture site, and the distal tip may detach and embolize. If a horizontal rupture occurs, the balloon can be removed by cutting off the proximal portion of the catheter and inserting a sheath 2-F size larger than the catheter (Fig 61).l’= Death is extremely rare following angioplasty. However, in patients with severe diffuse vascular disease, systemic complications may result in death. Therefore, angioplasty should not be undertaken without considering the risks in the individCurr

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FIG 61. Removing the stuck, ruptured balloon catheter. A, balloon catheter is divided just distal to the stopcock. B, Mylar sheath is inserted over the catheter and advanced into the femoral artery. C, balloon catheter is then retracted into the sheath. D, sheath and balloon are removed as a unit.

ual patient. The potential complications indicate the need for thoughtful selection of patients and careful techniques during the procedure.

peutic alternatives in order that patients receive optimal treatment tailored to individual anatomic and clinical situations.

CONCLUSION

Acknowledgments

mA is no longer an experimental procedure. Conceived by Charles Dotter1 and revolutionized by Andreas Griintzig,’ the procedure has been refined by worldwide experience. Extensive experience gained during the past 12 years has conclusively demonstrated the efficacy of PTA in the treatment of peripheral vascular, renovascular, and coronary disease. Early experience is now demonstrating that angioplasty is effective in the treatment of short isolated lesions in the aorta and in the treatment of selected lesions in the peroneal and tibial arteries. Investigators are now beginning to cautiously study the efficacy of angioplasty in the brachiocephalic vessels. The procedure has come far in a short period of time because the advantages of flA are significant. The procedure is relatively simple when compared with surgery, and it preserves tissue. It avoids general anesthesia and major surgery. The patient experiences far less morbidity. The procedure is relatively inexpensive when compared with surgery and markedly decreases the hospital stay.14’C152 Proper patient selection and technical expertise are important if optimal results are to be achieved. Therefore, it is imperative that angiographers become familiar not only with the techniques of angioplasty but also with the etiology, risk factors, clinical progression, and complications of vascular diseases. We must also be familiar with the theraCurr

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The thanks Sherry tion of

author expresses his appreciation and to Shirley Yowell, Geneva Shifflett, and Deane for their assistance in the preparathis manuscript. REFERENCES

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28. Abele JE: Balloon catheters and transluminal dilatation: Technical considerations. AJR 1980; 135:901-906. 29. Tegtmeyer CJ, Teates CD, Crigler N, et al: Percutaneous transluminal angioplasty in patients with renal artery stenosis: Follow-up studies. Radiology 1981; 140:323-330. 30. Tegtmeyer CJ, Kofler TJ, Ayers CA: Renal afgioplasty: Current status. AJR 1984; 142:17-21. 31. Tegtmeyer CJ, Kellum CD, Ayers C: Percutaneous transluminal angioplasty of the renal artery: Results and long-term follow-up. Radiology 1984; 153:77-&t. 32. Udoff EJ, Barth KH, Harrington DP, et al: Hemodynamic significance of iliac artery stenosis: Pressure measurements during angiography. Radiology 1979; 132286293. 33. Bridges RA, Baines RW: Segmental limb pressures, in Kempczinski RF, Yao JST teds): Practical Noninvasive Vascular Diagnosis. Chicago, Year Book Medical Publishers, Inc, 1982, p 89. 34. Kaufman SL, Barth KH, Kadir S, et al: Hemodynamic measurements in the evaluation and follow-up of transluminal angioplasty of the iliac and femoral arteries. Radiology 1982; 142:329-336. 35. Tegtmeyer CJ, Moore TS, Chandler JG, et al: Percutaneous transluminal dilatation of a complete block in the right iliac artery. AJR 1979; 133532-535. 36. Tegtmeyer CJ, Wellons HA, Thompson RN: Balloon dilation of the abdominal aorta. JAMA 1980; 2442636 2637. 37. Tegtmeyer CJ, Kellum CD, Kron IL, et al: Percutaneous transluminal angioplasty in the region of the aortic bifurcation: The two-balloon technique with results and long-term follow-up study. Radiology 1985; 157:661665. 38. Lynch WA, Westcott JL: “Blind’ femoral angiography. Radiology 1977; 125:379-382. 39. Dotter CT, Rosch J, Robinson M: Fluomscopic guidance in femoral artery puncture. Radiology 1978; 127266267. 40. Khangure MS, Chow KC, Christensen MA: Accurate and safe puncture of a pulseless femoral artery: An aid in performing iliac artery percutaneous transluminal angioplasty. Radiology 1982; 144:927-928. 41. Bachman DM, Casarella WJ, SOS TA: Percutaneous iliofemoral angioplasty via the contralateral femoral artery. Radiology 1979; 130:617-621. 42. Kadir S, Baassiri A, Barth KH: Technique for conversion of a retrograde into an antegrade femoral artery catheterization. AJR 1981; 136:430-431. 43. Tegtmeyer CJ, Ayers CA, Wellons HA: The axillary approach to percutaneous renal artery dilatation. Radiology 1980; 135:775-776. 44. SOS TA, Cohn DJ, Srur M, et al: Technical developments and instrumentation: A new open-ended guidewireicatheter. Radiology 1985; 154:817-818. 45. Stanley JC, Gewertz BL, Bove EL, et al: Arterial fibmdysplasia: Histopathologic character and current etiologic concepts. Arch Surg 1975; 110561-566. 46. Wylie EJ, Binkley FM, Palubinskas AJ: Extrarenal fibmmuscular hyperplasia. Am J Surg 1966; 112:149-155. 47. Thompson WM, Johnsrude IS, Jackson DC, et al: Late complications of abdominal aortic reconstructive surgery. Ann Surg 1977; 185:326-334. 48. Colapinto RF, Harries-Jones EP, Johnston KW: Percutaneous transluminal recanalization of complete iliac artery occlusions. Arch Surg 1981; 116277-281. 49. Pilla TJ, Peterson GJ, Tantana S, et al: Percutaneous Cum

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51. 52.

53. 54. 55.

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63. 64. 65. 66. 67. 68. 69. 70.

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