Evolving Applications of Coronary Angioplasty: Technical and Angiographic Considerations George W. Vetrovec, MD
Coronary angioplasty (PTCA) is now applicable to selected patients with multiple vessel disease, total occlusions, tandem lesions and complex branch disease. Operator experience and skill contribute to a high success rate in complex anatomy, but equally important is appropriate case selectii based on angiographic review of lesion morphology, branches, extent of coronary artery disease, and left ventricular function. Likewise, during and after the procedure similar angiographii assessment is important to determine resultant ~&MI morphology, branch anatomy, distal nmnoff, and adequacy of lesion dilatation. Thus, the outcome of angioplasty is dependent on the operator’s ability to opacity the coronary arteries with minimal or no vessel/lesion overlap or foreshortening. Although coronary angiography has become more routine for many angiographers with the advent of angioplasty, the importance of high-qua& angiography continues to beamajorcomponentforrueceuful angioplasty. (AmJ Cardid1989;64:27E42E)
ince the advent of percutaneous transluminal coronary angioplasty (PTCA) 12 years ago,’ striking technical advances have expanded the potential applications of angioplasty to patients with more complex coronary vascular disease. However, despite major technical improvements, there remains a significant clinical learning curve2T3that relates to the skill and experience of the operator. Furthermore, successnot only relates to the techniques of balloon and guidewire manipulation but to appropriate evaluation of patients before and after angioplasty regarding appropriate patient selection and followup. Continuing investigations have shown that patients with complex coronary disease are amenable to successful angioplasty. However, not all patients are candidates for angioplasty, and high-quality angiography is important to establish characteristics predicting a favorable outcome. This report discusses the expanding applications of routine and complex coronary angioplasty, particularly with regard to important anatomic considerations in selecting appropriate candidates. In addition, the significance of myocardial function as a consideration in patient selection will also be discussed. Finally, the importance of high-quality technical and angiographic skill required to achieve excellent success in complex disease is emphasized.
S
CORONARY
From the Medical College of Virginia, Richmond, Virginia. Address for reprints: George W. Vetrovec, MD, Box 36, MCV Station, Richmond, Virginia 23298.
ANATOMIC
CONSIDERATIONS
In the early days of coronary angioplasty experience, certain anatomic and clinical features were considered predictive of a lower successrate for dilatation.ly4 These factors included female gender, angina of longer duration, left circumflex stenoses, distal lesions, as well as eccentric lesion morphology and coronary calcification. However, more recent studies have suggested such factors are less important in determining angioplasty success. For example, preliminary reports from the MultiHospital Eastern Atlantic Restenosis Trial (M = Heart), which primarily sought to assessthe potential efficacy of high-dose, single-administration steroids to prevent restenosis, provided a significant data base relative to factors determining angioplasty s~ccess.~In this trial, 860 patients (663 men, 197 women, mean age 59 years, range 3 1 to 8.5 years) underwent coronary angioplasty. Forty-nine percent of the patients had angina for <3 months, 30% had angina 3 to 12 months before PTCA, whereas 21% had angina for >12 months. Seventy percent of patients were in class III or IV of the Canadian Heart Association classification. Twenty-four percent of the patients had prior myocardial infarction. In this trial,5 a total of 1,072 lesions were dilated: 5 1% in the anterior descending distribution, 21% in the cir-
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TABLE I Applications for Percutaneous Transluminal Coronary Angioplasty Multiple lesion/vessel disease After bypass surgery Branch lesions Nonacute total occlusions Myocardial infarction Left ventricular dysfunction
cumflex, and 25% in the right coronary distribution. Calcification was reported in 13% of lesions and eccentric disease was present in 53%, whereas 8% had angiographic evidence of local thrombus. Ten clinical and 9 anatomic features were analyzed before and after PTCA including age, gender and race, along with duration and severity of angina, prior myocardial infarction, presence of rest angina and transient ST-segment elevation. Anatomic features included the artery and site of dilatation along with artery size, and stenosis severity and length. Translesion gradient, eccentricity, calcification and coronary thrombus were also analyzed. Of these features, only 2 were significantly predictive of angioplasty outcome. There was a significantly lower successrate of 76% for patients with 99 and 100% stenoses, compared with an 87% success rate for 90 to 99% lesions, and 93% success for all other attempted lesions. Likewise, lesion calcification was associated with a lower successrate, the difference being 92% for noncalcified lesions vs 8 1% for calcified lesions (p 10.001). The only other factor potentially affecting outcome was the presence of coronary thrombus. The success rate was 6% lower for patients with angiographic evidence of lesion-associated coronary thrombus (92 vs 86%), but this difference was not significant (p = 0.11). Thus, lesion morphology, location and patient demographics appear to be of less significance in predicting angioplasty success with current technology. Based on these data, liberalization of the types of lesions selected for angioplasty is appropriate. MultIpIe vessetI diseaser Complex coronary angioplasty, defined as anything other than dilatation of a discrete arterial obstruction, is much more frequently performed. For example, in the last several years, over two-thirds of patients undergoing angioplasty at the Medical College of Virginia have complex disease including tandem lesions, branch disease, nonacute total occlusions and multiple vessel disease. Table I summarizes potential uses of coronary angioplasty. Of particular interest is angioplasty for patients with multiple vessel disease. Earlier reports suggested a slightly higher complication rate and perhaps slightly lower successrate for multiple vessel disease,6v7but with improved skill, equipment and patient selection, the successrate for multiple vessel disease is now comparable to that of single vessel disease. In major centers, clinical successrate exceeds 90% (dilatation of the primary lesion and in most instances successful dilatation of secondary lesions, as well with clinical improvement) .*19Major complications, i.e., death, urgent surgery and myocardial infarction, occur in approximate-
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ly 3 to 4% of patients. However, many reports of multiple vessel disease have included a major single arterial system with branch disease in a secondary system. Recently, DiSciascio et allo at the Medical College of Virginia reported the outcome of true 3-vessel coronary angioplasty in 50 patients. Patients were carefully selected to include only those whose individual major lesions were amenable to dilatation. Selection generally excluded patients in whom most of the functional myocardium was potentially compromised by complex collateral filling through the target artery. In this report, the overall lesion successrate was94%, with a clinical successrate of lOO%, i.e., the major artery being successfully dilated. Five patients had small non-Q-wave myocardial infarctions. This study illustrates that appropriately selected patients with multiple vessel disease (3-vessel disease) can effectively and safely undergo revascularization with coronary angioplasty. However, careful selection to identify the primary and secondary lesions for potential safe and successful dilatation is important under anatomic circumstances in which a single lesion/vessel supplies most of the functional myocardium, making a single lesion equivalent to a left main stenosis. Thus, in properly selected patients, multiple vessel angioplasty is an alternative to bypass surgery. Complex branch disease: We have previously reported the effect of dilatation on lesion-associated branches, demonstrating that the risk to the lesion-associated branch is related to the presence of associated ostial branch disease.ll In patients without ostial branch disease, the risk of adverse outcome to the branches was 4%, whereas the risk of branches that have associated ostial disease or contiguous disease between the primary lesion and the branch is 27%. Thus, in patients undergoing dilatation with major branches arising within the primary stenosis, branch protection becomes important when there is associated ostial branch disease. However, branches arising outside the area of dilated stenosis but within the area of the balloon inflation are at minimal risk for any adverse outcome.‘* Thus, techniques have been developed to provide access or alternate or simultaneous balloon inflations, or a combination of these, involving primary arterial stenoses with major diseased branches.13J4 These techniques continue to evolve in response to improved technical equip ment. With larger 8Fr or 9Fr guiding catheters, simultaneous dilatation or lesion access,or both, can be obtained using a single guide catheter. Dual guide catheter insertion and simultaneous inflations have frequently been necessary for dual balloon access (Fig. 1). With the advent of smaller profile balloons, particularly with lower shaft sizes and the non-over-the-wire systems plus large bore-guiding catheters, it has become increasingly easy to protect significant branches while successfully dilating both lesions with a single guiding catheter approach. Nenawte total oeeludons: As experience with coronary angioplasty has evolved, greater success has been achieved in nonacute total occlusions. Success rate is clearly dependent on estimated length of time of total
FIGURE sbncmis.
1. Complex branch angbpkty using dual balbons and guiding Middle panel shows simultaneous dual balloon inflation. Right
occlusion.15J6 For recent occlusions (usually defined as <7 days), the success rate is clearly that of nontotal occlusions. Conversely, for more chronic stenoses, although still potentially treatable even up to the years after presumed occlusion, the successrate is substantially less. In more than 250 patients undergoing nonacute total occlusion dilatation at the Medical College of Virginia, the success rate for nonacute total occlusions was nearly 90%, only slightly lower than that for nontotal lesions. The most important predictive factor for success is whether a wire can traverse the stenosis. If a guidewire is across the lesion, the stenosis can almost always be dilated. The risk of urgent surgery for nonacute total dilatations is low, because most of these arteries are well collateralized. Urgent surgery is necessary only if dilatation involves occlusion of a large adjacent branch or another nontotal vessel system being dilated. One interesting facet of angioplasty for nonacute total occlusions is restenosis. In our experience,16 clinical recurrence rates are significantly higher for nonacute total occlusions than for nontotal lesions. Clinical restenosis for nonacute total occlusions is approximately 30%, whereas at our center the recurrence rate for nonacute total occlusions is approximately 20%. Restenosis seems particularly more common for recent total occlusions. Thus, nonacute total occlusions are potentially dilatable with a somewhat lower success rate but only minimally reduced for patients with evidence of recent total occlusion. The risk or need for urgent surgery is low. However, the recurrence rate seems to be somewhat increased. APPLICATION MYOCARDIAL
OF ANGIOPLASTY FUNCTION
TO
lschemii left ventricular dysfunction: There is considerable interest regarding the potential reversibility of
catheters. Left pane/illustrates pane/ demonstrates an excedhl
a severe! bHwca&d an&graphic result.
stunned or hibernating myocardial dysfunction. In patients with recent unstable angina, the extent of left ventricular function is often much greater than the extent of later chronic dysfunction, provided ischemia is eliminated. Furthermore, the extent of left ventricular dysfunction is a predictor of adverse outcome17 Thus, there is much greater emphasis on revascularization in the management of coronary artery disease in patients with evidence of ongoing ischemia but with abnormal left ventricular function. Unstable angina: In a recent report,18 we evaluated the effect of successful angioplasty on acute left ventricular function in patients with stable and unstable angina. Both underwent successful single vessel dilatation and had no history of myocardial infarction. The patients with stable angina had normal resting left ventricular function at the time of dilatation, which did not change after successful angioplasty. In contrast, patients with recent unstable angina (although without symptoms during the previous 24 hours) had a significantly lower resting ejection fraction than did the stable group, again despite no prior myocardial infarction. However, mean ejection fraction levels became normal after successful dilatation of the unstable patients. Likewise, depressed segments within the distribution of the dilated arteries had the greatest improvement after successful dilatation. These findings demonstrate the frequently observed depression of ventricular function seen in unstable angina as well as the importance of revascularization for normalizing depressed function in patients with unstable angina. A recent study,i9 using echocardiography before and after PTCA, showed a significant improvement in wall motion abnormality in patients who had preexisting depression of left ventricular function. Most of these patients had prior myocardial infarction but ongoing ischemia. Thus, in patients with depressed ventricular func-
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tion but with evidence of ischemia, the potential for reversing ventricular function is substantial. This reflects a change in our approach to patients with coronary artery disease in which previous indications frequently excluded patients with severe left ventricular dysfunction. coronary angioplasty afPercutaneous transluminal ter cardiac transplantation: In the first year after cardiac
transplantation, the major risk to morbidity and mortality is acute rejection or infection related to immunosuppression, or both. Although rejection continues to be a chronic problem, in later years after transplantation, a major contributor to organ failure is the development of coronary vascular disease.2o This occurs in 2 types: small vessel, distal diffuse disease and a more proximal disease that angiographically appears similar to a more typical atherosclerotic obstructive coronary disease. The small vessel disease may occur earlier, whereas the proximal disease most frequently occurs several years after transplantation. Because transplanted hearts remain denervated, patients clinically experience no ischemic pain and, thus, many present with myocardial infarction manifested only as fatigue, shortness of breath, or electrocardiographic changes of recent infarction, or a combination. A study from the Medical College of Virginia21 reports success in dilating patients with heart transplants with proximal, major vessel coronary artery disease. Eight procedures were performed in 5 patients in an attempt to extend the longevity of the transplanted hearts while awaiting either repeat transplantation or to improve the clinical outcome for the patients. To date, the overall outcome has been good after dilatation for these patients, although in I patient with very aggressive vascular disease, the effect of angioplasty was simply to extend TABLE II Percutaneous Technical
Transluminal Considerations-Significance
Coronary Angioplasty: of Angiography
Lesion morphology before angioplasty Results/splits/morphology after angioplasty Branch anatomy, disease Additional lesions
stenosis
n
$
90%
I
the function of the heterograft long enough to permit repeat transplantation. In summary, cardiac transplant recipients represent a unique group of patients who may benefit from angioplasty revascularization to extend the usefulness of the transplanted heart. TECHNICAL CONSIDERATIONS FOR SUCCESSFUL ANGIOPLASTY Excellence in coronary angiography is an important component for successful angioplasty. In contrast to preoperative angiography for coronary artery bypass surgery, preangioplasty angiography is even more important to define lesion anatomy as well as significant branch disease. Table II indicates the specific information learned from angiographic lesion morphology. Leaion morphdogy: An important aspect of lesion morphology is recognition of the presence of coronary thrombus. For example, we have reported22 that the presence of lesion thrombus, either before or immediately after successful dilatation suggests an increased risk of acute closure immediately after angioplasty. Acute closure soon after initial successful coronary angioplasty is also frequently associated with recent unstable angina or myocardial infarction, or both, in the dilated lesions, which is not unexpected based on current understanding of the pathophysiology of these clinical syndromes (Fig. 2). In addition to thrombus, flow compromising dissection can produce acute occlusion, although in our experience this seems to occur much less often, possibly based on the high incidence of patients with unstable angina undergoing angioplasty in our institution. In patients clinically and angiographically defined as high risk for early occlusion, angiographic observation for 10 to 20 minutes after the procedure is useful, since 80% of our patients had acute occlusion within the first 15 minutes after dilatation. The use of sequential angiography allows the operator to identify a potential acute closure before it occurs, reducing the probability of uncontrolled occlusion that might result in emergency coronary bypass surgery or infarction, or both. Repeat dilatation is frequently
filling defect
80-
68% FlGURE 2. AnglugraPlk findings seen in Pstlenbwsthaa4tecloswe.Notetheinclfkwceor”~ordluectionslsnstslgSMcanuy-fromthatrorrucceorful dllhthSWRhOUtaartedorwa.pOSt= after;prs=bafws.
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successful, further emphasizing the importance of early closure recognition to enhance procedure outcome. These results underscore the importance of identifying pre- or post-PTCA lesion morphologic changes of thrombus or major dissection, or both. Careful identification by appropriate views and excellent opacification is very important for adequate angiography to support dilatation procedures. TABLE
III Special
Views:
View
Left Coronary
Artery
Vessel Segment
Special angiographii views: Although most physicians performing angioplasty are very familiar with angioplasty views, certain views can be very helpful to assess specific coronary segments. Tables III and IV illustrate useful views for specialized segments of the right and left coronary arteries. For example, the lateral view of the right coronary is a less frequently used projection for right coronary artery dilatations but is frequently useful to define midvessel
r
TABLE
I
IV Special
Views:
Right Coronary
View
~ng artery-posterior
Artery
I
Vessel Segment
lateral branch
RCA = right coronary
I
artery.
FlGURE3.Exmpleof-oflateralrightcxmnatyartery(RCA)vlewleras-
views.LAG-CR=leRmtedorobliwecrallial;LAT=lateral;PTCA~perdamolKtr-coroMly~ RAO = right anterior ebbqus.
;
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branch anatomy, as well aslesion morphology beforeand after dilatation.23Figures 3 and 4 illustrate the usefulness of the lateral view, particularly for midvessellesionseven in total right coronary occlusions. Visual opacification: Adequate opacification is an important aspectof lesion assessmentbefore,after and during angioplasty. The useof higher flow guiding catheters, particularly with smaller shaft balloon catheters, allows much better visualization during the angioplasty procedure. Figure 1 also illustrates the circumstance in which use of over-the-wire extension of dual wire accessof the anterior descendingand diagonal branchesremoving the balloon from the guiding catheter allowed excellent opacification, identifying an inadequate result after alternate balloon inflations. This prompted dual balloon inflations. After the so-called“kissing balloon” technique,there was an excellent angiographic result again illustrated while the wires are still in place. Using small shaft balloons or extensionwires, or both, to decreaseresistanceto contrast injection allows improved lesion assessmentbefore removing guidewire access.
5. Savage M, Goldberg S, Hirshfeld J, Bass T, MacDonald R, Margolii J, TaussigA, Vetrovec G, Whitworth H, Cowley M, Jugo R, PepineC for the MHeart Group. Determinants of primary angioplasty success:a report from the Multi-Hospital Eastern Atlantic RestenosisTrial (M-Heart) (abstr). Cothet Cardiovasc Diagn 1988;15:203-204.
6. Breedlau CE, Roubin GS, Leimgruber PP, Douglas JH, King SB, Gruentzig AR. In-hospital morbidity and mortality in patientsundergoingelectivecoronary angioplasty. Circulation 1985;72:1044-1052. 7. Kent KM, Bentivoglio LG, Block PC, Cowley MJ, Dorms G, GosselinAJ, Gruentzig A, Myler RK, Simpson J, Stertzer SH, Williams DO, Fisher L, Gillespie MJ, Detre K, Kelsey S, Mullin SM. Mock MB. Percutaneoustransluminal angioplasty:Registry of National Heart, Lung, and Blood Institute. Am J Cardiol 1982;49:201 l-2020.
9. Myler RK, Top01EJ, Shaw RE, Stertzer SH, Clark DA, FishmanJ, Murphy MC. Multiple vesselcoronary angioplasty:classification, results, and patterns of reatenosisin 494 consecutivepatients. Cathet Cardiouasc Diagn 1987;13:1-15. 9. Cowley MJ, Vetrovec GW, DiSciascioG, Lewis SA, Hirsh PD. Wolfgang TC. Coronary angioplasty of multiple vessels:short-term outcomeand long-term results. Circulation 1987;72:1314-1320. 10. DiSciascioG, Cowley MJ, Vetrovec GW, Kelly KM, Lewis SA. Triple vessel coronary angioplasty: acute outcome and long-term results. JACC 1988;12:4248. 11. Vetrovec GW, Cowley MJ, Wolfgang TC, Ducey KC. Effects of percutane oustransluminal coronary angioplastyon lesion-associatedbranches.Am Heart J 1985;109:921-925.
12. Meier B, Gmentzig AR, King SB, Douglas JS, Holhnan J, Ischinger T, Aueron F, Galan K. Risk of side branch occlusionduring coronary angioplasty. Am J Cardiol 1984;53:1 O-l 4.
13. Meier B. Kissing balloon coronary angioplasty.Am J Cardiol1984,54:918919.
SUMMARY Excellenceremainsan important componentof angioplasty. Complex coronary angioplasty is not only possible but also quite feasibleprovided appropriate selectionfactors are considered. Individual lesions are much more amenableto angioplasty than in the past, although extent of viable myocardium at rest remains an important consideration. With use of well-defined selection criteria, angioplasty for very complex coronary artery diseaseis everexpanding. With greater applicability to a variety of anatomic conditions, coronary angioplasty representsa reasonable substitute for bypass surgery in increasingly complex anatomy. REFERENCES 1. Gruentzig AR, Senning A, Siegenthaler WE. Non-operative dilatation of coronary artery stenosis:percutaneoustransluminal coronary angioplasty.N Eng/ J Med 1979;301.61-68.
2. Meier B, Gruentzig AR. Learning curve for PTCA: skill, technology and patient selection. Am J Cardiol 1984$3.6X-66C. 3. Kelsey SF, Mullin SM. Detre KM, Mitchell H, Cowley MJ, Gruentzig AR, Kent KM. Effects of investigator experience on PTCA. Am J CardioZ1984;53: 56C-64C. 4. Anderson HV, Roubin GS, Leimgruber PP, Douglas JS, King SB, Gruentzig AR. Primary angiographic successrates of percutaneoustransluminal coronary angioplasty. Am J Cardiol 1985:56:712-717.
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14. GeorgeSB, Myler RK, Stertzer SH, Clark DA, Cote G, Shaw RE, FiihmanRosen J, Murphy M. Balloon angioplasty of coronary bifurcation lesions: the kissing balloon technique. Cathet Cardiovasc Diagn 1986:12:124-l 38. 15. Holmes DR. Vbatra RE, ReederGS, BresnahanJF, Smight HC, Bove AA, Schaff HV. Angioplasty in total coronary artery occlusion.JACC 1984;3:845849.
16. DiSciascio G, Vetrovec GW, Cowley MJ, Wolfgang TC. Early and late outcome of percutaneoustransluminal coronary angioplasty for subacute and chronic total coronary occlusion.Am Heart J 1986;111:833-839. 17. Nixon JV, Brown CN, Smitherman TC. Identification of transient and persistentsegmentalwall motion abnormalities in patients with unstable angina by two-dimensional echocardiography.Circulation 1982,5:1497-1503. 18. Carbon EB, Cowley MJ, Wolfgang TC, Vetrovec GW. Acute changesin global and regional resting left ventricular function after successfulpercutaneous transluminal coronary angioplasty: comparative results in stable and unstable angina. JACC 1989:13:1262-l 269. 19. van den Berg EK, Dehmer GJ, Snow F, RosenbergH, Lewis S, Vetrovec GW, Nixon JV. Reversibility of segmentalleft ventricular dysfunction following coronary angioplasty: echocardiographicevidenceof hibernating myocardium, abstracted.JACC 1988:11:133A. 20. Gao SZ, SchroederJS, Alderman EL, Hunt SA, Silverman JF, Wiederhold V, Stinson EB. Clinical and laboratory correlates of acceleratedcoronary artery diseasein thecardiac transplant patient. Circulation 1987;76:suppl V?V-56- V-61. 21. Vetrovec GW, Cowley MJ, Newton CM, Lewis SA, DiSciascioG, Thompson JA, Hastillo A, Lower R, Hess M. Applications of percutaneoustransluminal coronary angioplasty in cardiic transplantation: preliminary results in five patients. Circulation
1988:78:suppl III:III-83-M-86.
22. Goldbaum T, Diiio G, Cowley MJ, Vetrovec GW. Early occlusion following successfulcoronary angioplasty:clinical and angiographicobservations. Cathet Cardiovasc Diagn 1989;17:22-27.
23. Goldbaum TS, DiS&scio G, Cowley MJ, Vetrovec GW. The usefulnessof the lateral projection in the assessmentof the right coronary artery during percutaneous transluminal coronary angioplasty. Cathet Cardiovasc Diagn 1987;13: 277-283.