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Cutting balloon: A novel approach to percutaneous angioplasty
ies may occur even in patients with high transthoracic image quality, all patients with negative transthoracic findings should undergo transesophageal contrast echocardiography in search of a patent foramen ovale.
1. Harvey JR, Teague SM, Anderson JL, Voyles WF, Thadani U. Clinically silent atria1 septal defects with evidence for cerebral embolization. Ann Intern Med 1986;105:695-697. 2. Webster MW, Smith HJ, Sharpe DN, Chancellor AM, Swift DL, Bass NM, Glasgow GL. Patent foramen ovale in young stroke patients. Lancet 1988; 2:11-12. 3. Lechat P, Mas JL, Lascault G, Loron PH. Theard M, Klimczak M, Drobinski G, Thomas D, Grosgogeat Y. Prevalence of patent foramen ovale in patients with stroke. N Engl .I Med 1988;318:1148-1152.
4. Seward JB, Tajik AJ, Spangle1 JG, Riter DC. Echocardiographic contrast study: initial experience. Mayo Clin Proc 1975;50:163-192. 5. Valdes-Cruz LM, Pieroni DR, Roland JMA, Varghese PJ. Echocardiographic detection of intracardiac right to left shunts following peripheral vein injections. Circulation 1976;54:558-562. 6. Kronik G, Mijsslacher H. Positive contrast echocardiography in patients with patent foramen ovale and normal right heart hemcdynamics. Am J Cardiol 1982;49:1806-1809. 7. Lynch JJ, Schuchard GH, Gross CM, Wann LS. Prevalence of right to left atria1 shunting in a healthy population: detection by Valsalva maneuver-contrast echocardiography. Am J Cardiol 1984;53:1478-1480. 8. Dubourg 0, Boardarias JP, Farcot JC, Gueret P, Terdjman M. Contrast echocardiographic visualization of cough-induced right to left shunt through a patent foramen ovale. J Am Co11 Cardiol 1984;4:587-594. 9. Geibel A, Kasper W, Behroz A, Przewolka U, Meinertz T, Just H. Risk of transesophageal echocardiography in awake patients with cardiac diseases. Am J Cardiol
1988;62:337-339.
Cutting Balloon: A Novel Approach to Percutaneous Peter Barath,
MD,
PhD,
Michael C. Fishbein,
MD,
Sandor Vari,
alloon angioplasty typically injures the vesselwall by inducing irregular intimal tears, splits and stretches.’ Proliferative response to this injury,2 and elastic recoil3 after balloon angioplasty are implicated as causes of restenosis and acute closure, respectively. We hypothesized that sharp and regular endovascular surgical incisions may enhance the successof angioplasty by limiting both injury and elastic recoil. We designed devices to make radially directed, longitudinal surgical cuts from the luminal surface deepening into the medial layer. In thii study we used 1 of the possible designs (Figure 1). One to 4 cutting edges of 0.1 to 0.4 mm metal blades were mounted on the surface of balloon catheters parallel with the longitudinal axis of the balloon (cutting balloon). The aims of the study were to (1) determine the immediate morphology of incisions made with the cutting balloon; (2) determine the healing response to the endovascular incisions; and (3) compare angiographic results obtained with standard and cutting balloons.
B
MD,
Angioplasty
and James S. Forrester,
MD
We performed angioplasty in the normal peripheral arteries of 18 farm pigs under general anesthesia with either standard or cutting balloon catheters. The animals werefully heparinizedfor 24 hours. The balloon catheters were delivered to the site of the intervention via a 9Fr multipurpose catheter through a carotid cut down. Balloon size 10% to 15% greater than the baseline angiographic vessel size was chosen for both standard and cutting balloon dilatations. The balloons were inflated with a pressure needed to reach the nominal angiographic diameters of the balloons. In acute experiments (n = 7) 7 femoral arteries were dilated on 1 side with the standard balloon, and on the
From the Division of Cardiology, Department of Medicine, CedarsSinai Medical Center, Los Angeles, California 90048. This study was supported by a grant from the Grant Foundation, Cedars-Sinai Medical Center, Los Angeles, California. Manuscript received and accepted June 24,199l.
FIGURE 1. Model oi cutting device thlepal+warmodel4alttlngedgesweremeuntedlIllof 2.0 mm balkon catheter.
with
Mated
balloon.
In
FlGURE2.Gvewiewofcrosssectionofnormdartery4hours after cutting with cutting device without diion. In thii exampleweinftatedtheballoonbutdidnotuseenoughpressure toreachllomlnalofthebanoon,whiiwas15% greater than original vessel &am&r. Two in&h3 (arrows) are visibte on the section extending into the medial layer. Edgesofhcisbns arenotseparated.Therestofarterydoes net show any changes. EnWhellal layer is preserved outside of incishs (X5).
BRIEF REPORTS
1249
TABLE I Occurrence of Histological Changes Four Hours After Angioplasty with Standard and Cutting Balloons in Normal Pig Arteries
Endothelial denudation IEL disruption lntimal tears > 50 U SMC stretch Corkscrew nuclei Cytoplasmic degeneration
cB* (%)
SB (%I
45 0 0 11 15 0
100 85 81 99 100 100
*O. 1 m m outside the cutting edges.
CB = cutting balloon;
IEL = internal elastic lamina: SB = standard
balloon;
SMC =
smooth musclece11s.
FIGURE 3. Acute effect of angioplasty m with cutting balioon.A,crosssectlonofnormalartery4heursaftercuttlng and dilating wlth cutllng balloon. In this case, babon with lcuttingedgewasused.BalloonwasinRatedoncefor3oseeends. Balloon reached its nominal diameter with inttatlon pressure of 3.5 abn. Edges of Incision (arrowheads) are widely separated. Bass of incision is flat and smooth. Thsre are no intimal tears or medial dWchss present (X3). 6, higbsr magnification of lumiil surface of incision. Bass of incision is flat and smooth, and covered wlth a thin layer of fibrin. Adjacent intimal surface is normal (Xso).
1250
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
other side with the cutting balloon. The animals were sacrificed 4 hours after the intervention. In the chronic experiments (n = 1 I), 20 arteries (iliac and distal) were dilated with standard and 23 with cutting balloon catheters. The animals were sacrificed 14 days after the intervention. In the chronic experiments angiography was repeated immediately after dilatation, as well as 1,2 and 4 hours, and I4 days after intervention. Serial histological sections were cut from paraff&t-embedded tissue, and stained with hematoxylin and eosin. Figure 2 shows the effect of partial inflation of the cutting balloon 4 hours after intervention. Two sharp incisions extend into one to two thirds of the medial layer. The edges of the wound are in close apposition. Figures 3A and B show the effect of complete inflation of a cutting balloon. The edges of the wound are widely separated, forming a shallow dimple with flattened smooth muscle cells at the base.
FIGURE 4. Effect of angiopksty with cutlmg balloon 14 days after dilatation: A, site of incision is recognizable as slightly elevated region wlth crater (arrow) (x5). 6, higher magniftcation shows that saface of incision is rsemlothelialized. Defect is filled by progfarative smooth muscle cells. I-1 elastic lamii ends at edges of cuts (arrowheads). The rest of artery is intact with no intimai pretiferation. NOVEMBER
1, 1991
intimal proliferation outside the cutting area in the arteries incised by the cutting balloon. There are several limitations of this study. There are a number of technical problems to be solved including size and flexibility of the device, and protection of the normal segment from the blades during catheter passage. To test the device in vessel diameters comparable with those in humans, we used the pig model in which balloon dilatation induces intimal hyperplasia, although to a lesser extent than in rodents.s Our results do not necessarily mean that in the long-term there will be no intimal hyperplasia, although previous investigations in other models have shown that the total number of smooth muscle cells in the intima peaks at 2 weeks and remains relatively constant up to 1 year.6 We also are not able to predict whether localized hyperplasia at the incision site may develop at a later time. We used normal arteries for this in vivo study. Although the device proved to be effective in cutting human atheroma in cadaver arteries we cannot predict how such a device would cut atheroma in vivo. The result of exposing the atheroma contents to the flowing blood stream by an in vivo incision also remains to be determined. The data obtained after 1 type of balloon angioplasty (standard or cutting) from the different levels of the arterial tree were pooled. We inflated the balloons to their nominal diameter; because of the cutting action of the device, the inflation pressure was less with the cutting than with the standard balloon. We also used 1 inflation with the cutting and 3 with the standard balloon catheter. Thus, although the angiographic outcome was similar, the stimulus to hyperplasia was not. Nevertheless, the clear distinction between the responses to angioplasty with the standard and cutting balloons, characterized by lack of proliferation after using the cutting balloon, appears to be consistent despite the many individual variations. The method described herein could have implications for angioplasty in humans. The potential advantages of
Table I compares the histological changes seen 4 hours after dilatation using standard and cutting balloon catheters. The frequency of histological indicators of the balloon dilatation-induced injury is lower after dilatation with the cutting than with the standard balloon catheter. In chronic experiments, the site of the incision was recognizable as a broad, shallow crater. Figures 4A and B show that 14 days after intervention, the luminal surface of the cuts is endothelialized. The base of the wound is filled with smooth muscle cells. There is no inflammatory cell infiltration present. After angioplasty with the cutting balloon there was no intimal proliferation outside the cut area compared with an 8.7% proliferative area (as a percentage of the media) after angioplasty with the standard balloon. Figure 5 compares the angiographic vessel diameter after dilatations with the standard and cutting balloons. The diameters immediately after dilatation with the cutting and standard balloons were greater than the vessel sizes before angioplasty by 11 (standard error of the mean f 4) and 13% ( f 2) respectively. The diameter of the arteries after angioplasty with the standard balloon decreased to 5% above the original diameter within 1 hour, and decreased below baseline at sacrifice by 5%, whereas the vessel diameter remained 9% (standard error of the mean f 3) greater than the original diameter at that time after angioplasty with the cutting balloon.
In this report we describe a new concept of angioplasty based on the premise that sharp incisions repair with less scar formation and remain more circumscribed than wounds created by tears4 We produced sharp, longitudinal surgical incisions directed radially into the media with our cutting balloon catheter. The histological damage outside the cut area was less after dilation with the cutting than with standard balloon. This study also demonstrated an excellent healing process with complete reendothelialization of the surface at 14 days without
I FIGURE 5. Angiiraphic after angioplasty with cutting banWnS. The
T
151
1
vessel size standard and y axis
shows
per-
ceiltlk!changesefv~sixe.Thex
axis shows time when measurements wefe obtained. Percentage of dilatation was similar with both types ol interventbns. After angleplasty with cenventienal balben, angiegraphic vessei di-Si~~Withill
1 hour, whereas after angtoplasty with cutting balloon it remains practically the same, even at 14 days. N.S. = not siw. t. l
MS. PC.01
BRIEF REPORTS
1251
combining cutting and dilation are that: (1) by cutting deeply into the medial layer restitution of the vascular tone is decreased, thereby decreasing dilatation time and pressure; (2) with the sharp, surgical incision, less medial smooth muscle cell stretch may induce less growth factor expression and, thus, less intimal proliferation; and (3) the vascular injury is localized to the incision site. 1. Mizuno K, Jurita A, Imazeki N. Pathologic finding after percutaneous transluminal angioplasty. 5r Heart J 1984;18:476-484.
1252
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
2. Austin GE, Ratliff NB, Hollman J, Tabei S, Phillips DF. Intimal proliferation of smooth muscle cells as an explanation for recurrent coronary artery stenosis after percutaneous transluminal angioplasty. d Am Coil Cardiol1985;6:369-375. 3. Waller BF. “Crackers, breakers, stretchers, drillers, scrapers, shavers, burners, welders and melters”-the future treatment of atherosclerotic coronary artery disease? A clinical-morphologic assessment. J Am Coil Cardiol 1989;13: 969-987. 4. Medden JW, Arem AJ. Wound healing: biologic and clinical features, In: Sabiston DC, ed. Textbook of Surgery. Philadelphia: Saunders, 1986:193. 5. Walker LN, Ramsay MM, Bowyer DE. Endothelial healing following defined injury to rabbit aorta. Atherosclerosis 1983;47:123-130. 6. Steele PM, Chesebro JH, Stanson AW, Holmes DR, Dewanjee MK, Badimon L, Fuster V. Balloon angioplasty. Natural history of the pathophysiological response to injury in a pig model. Circ Res 1985;57:105-112.
NOVEMBER
1, 1991
1. Harvey JR, Teague SM, Anderson JL, Voyles WF, Thadani U. Clinically silent atria1 septal defects with evidence for cerebral embolization. Ann Intern Med 1986;105:695-697. 2. Webster MW, Smith HJ, Sharpe DN, Chancellor AM, Swift DL, Bass NM, Glasgow GL. Patent foramen ovale in young stroke patients. Lancet 1988; 2:11-12. 3. Lechat P, Mas JL, Lascault G, Loron PH. Theard M, Klimczak M, Drobinski G, Thomas D, Grosgogeat Y. Prevalence of patent foramen ovale in patients with stroke. N Engl .I Med 1988;318:1148-1152.
4. Seward JB, Tajik AJ, Spangle1 JG, Riter DC. Echocardiographic contrast study: initial experience. Mayo Clin Proc 1975;50:163-192. 5. Valdes-Cruz LM, Pieroni DR, Roland JMA, Varghese PJ. Echocardiographic detection of intracardiac right to left shunts following peripheral vein injections. Circulation 1976;54:558-562. 6. Kronik G, Mijsslacher H. Positive contrast echocardiography in patients with patent foramen ovale and normal right heart hemcdynamics. Am J Cardiol 1982;49:1806-1809. 7. Lynch JJ, Schuchard GH, Gross CM, Wann LS. Prevalence of right to left atria1 shunting in a healthy population: detection by Valsalva maneuver-contrast echocardiography. Am J Cardiol 1984;53:1478-1480. 8. Dubourg 0, Boardarias JP, Farcot JC, Gueret P, Terdjman M. Contrast echocardiographic visualization of cough-induced right to left shunt through a patent foramen ovale. J Am Co11 Cardiol 1984;4:587-594. 9. Geibel A, Kasper W, Behroz A, Przewolka U, Meinertz T, Just H. Risk of transesophageal echocardiography in awake patients with cardiac diseases. Am J Cardiol
1988;62:337-339.
Cutting Balloon: A Novel Approach to Percutaneous Peter Barath,
MD,
PhD,
Michael C. Fishbein,
MD,
Sandor Vari,
alloon angioplasty typically injures the vesselwall by inducing irregular intimal tears, splits and stretches.’ Proliferative response to this injury,2 and elastic recoil3 after balloon angioplasty are implicated as causes of restenosis and acute closure, respectively. We hypothesized that sharp and regular endovascular surgical incisions may enhance the successof angioplasty by limiting both injury and elastic recoil. We designed devices to make radially directed, longitudinal surgical cuts from the luminal surface deepening into the medial layer. In thii study we used 1 of the possible designs (Figure 1). One to 4 cutting edges of 0.1 to 0.4 mm metal blades were mounted on the surface of balloon catheters parallel with the longitudinal axis of the balloon (cutting balloon). The aims of the study were to (1) determine the immediate morphology of incisions made with the cutting balloon; (2) determine the healing response to the endovascular incisions; and (3) compare angiographic results obtained with standard and cutting balloons.
B
MD,
Angioplasty
and James S. Forrester,
MD
We performed angioplasty in the normal peripheral arteries of 18 farm pigs under general anesthesia with either standard or cutting balloon catheters. The animals werefully heparinizedfor 24 hours. The balloon catheters were delivered to the site of the intervention via a 9Fr multipurpose catheter through a carotid cut down. Balloon size 10% to 15% greater than the baseline angiographic vessel size was chosen for both standard and cutting balloon dilatations. The balloons were inflated with a pressure needed to reach the nominal angiographic diameters of the balloons. In acute experiments (n = 7) 7 femoral arteries were dilated on 1 side with the standard balloon, and on the
From the Division of Cardiology, Department of Medicine, CedarsSinai Medical Center, Los Angeles, California 90048. This study was supported by a grant from the Grant Foundation, Cedars-Sinai Medical Center, Los Angeles, California. Manuscript received and accepted June 24,199l.
FIGURE 1. Model oi cutting device thlepal+warmodel4alttlngedgesweremeuntedlIllof 2.0 mm balkon catheter.
with
Mated
balloon.
In
FlGURE2.Gvewiewofcrosssectionofnormdartery4hours after cutting with cutting device without diion. In thii exampleweinftatedtheballoonbutdidnotuseenoughpressure toreachllomlnalofthebanoon,whiiwas15% greater than original vessel &am&r. Two in&h3 (arrows) are visibte on the section extending into the medial layer. Edgesofhcisbns arenotseparated.Therestofarterydoes net show any changes. EnWhellal layer is preserved outside of incishs (X5).
BRIEF REPORTS
1249
TABLE I Occurrence of Histological Changes Four Hours After Angioplasty with Standard and Cutting Balloons in Normal Pig Arteries
Endothelial denudation IEL disruption lntimal tears > 50 U SMC stretch Corkscrew nuclei Cytoplasmic degeneration
cB* (%)
SB (%I
45 0 0 11 15 0
100 85 81 99 100 100
*O. 1 m m outside the cutting edges.
CB = cutting balloon;
IEL = internal elastic lamina: SB = standard
balloon;
SMC =
smooth musclece11s.
FIGURE 3. Acute effect of angioplasty m with cutting balioon.A,crosssectlonofnormalartery4heursaftercuttlng and dilating wlth cutllng balloon. In this case, babon with lcuttingedgewasused.BalloonwasinRatedoncefor3oseeends. Balloon reached its nominal diameter with inttatlon pressure of 3.5 abn. Edges of Incision (arrowheads) are widely separated. Bass of incision is flat and smooth. Thsre are no intimal tears or medial dWchss present (X3). 6, higbsr magnification of lumiil surface of incision. Bass of incision is flat and smooth, and covered wlth a thin layer of fibrin. Adjacent intimal surface is normal (Xso).
1250
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
other side with the cutting balloon. The animals were sacrificed 4 hours after the intervention. In the chronic experiments (n = 1 I), 20 arteries (iliac and distal) were dilated with standard and 23 with cutting balloon catheters. The animals were sacrificed 14 days after the intervention. In the chronic experiments angiography was repeated immediately after dilatation, as well as 1,2 and 4 hours, and I4 days after intervention. Serial histological sections were cut from paraff&t-embedded tissue, and stained with hematoxylin and eosin. Figure 2 shows the effect of partial inflation of the cutting balloon 4 hours after intervention. Two sharp incisions extend into one to two thirds of the medial layer. The edges of the wound are in close apposition. Figures 3A and B show the effect of complete inflation of a cutting balloon. The edges of the wound are widely separated, forming a shallow dimple with flattened smooth muscle cells at the base.
FIGURE 4. Effect of angiopksty with cutlmg balloon 14 days after dilatation: A, site of incision is recognizable as slightly elevated region wlth crater (arrow) (x5). 6, higher magniftcation shows that saface of incision is rsemlothelialized. Defect is filled by progfarative smooth muscle cells. I-1 elastic lamii ends at edges of cuts (arrowheads). The rest of artery is intact with no intimai pretiferation. NOVEMBER
1, 1991
intimal proliferation outside the cutting area in the arteries incised by the cutting balloon. There are several limitations of this study. There are a number of technical problems to be solved including size and flexibility of the device, and protection of the normal segment from the blades during catheter passage. To test the device in vessel diameters comparable with those in humans, we used the pig model in which balloon dilatation induces intimal hyperplasia, although to a lesser extent than in rodents.s Our results do not necessarily mean that in the long-term there will be no intimal hyperplasia, although previous investigations in other models have shown that the total number of smooth muscle cells in the intima peaks at 2 weeks and remains relatively constant up to 1 year.6 We also are not able to predict whether localized hyperplasia at the incision site may develop at a later time. We used normal arteries for this in vivo study. Although the device proved to be effective in cutting human atheroma in cadaver arteries we cannot predict how such a device would cut atheroma in vivo. The result of exposing the atheroma contents to the flowing blood stream by an in vivo incision also remains to be determined. The data obtained after 1 type of balloon angioplasty (standard or cutting) from the different levels of the arterial tree were pooled. We inflated the balloons to their nominal diameter; because of the cutting action of the device, the inflation pressure was less with the cutting than with the standard balloon. We also used 1 inflation with the cutting and 3 with the standard balloon catheter. Thus, although the angiographic outcome was similar, the stimulus to hyperplasia was not. Nevertheless, the clear distinction between the responses to angioplasty with the standard and cutting balloons, characterized by lack of proliferation after using the cutting balloon, appears to be consistent despite the many individual variations. The method described herein could have implications for angioplasty in humans. The potential advantages of
Table I compares the histological changes seen 4 hours after dilatation using standard and cutting balloon catheters. The frequency of histological indicators of the balloon dilatation-induced injury is lower after dilatation with the cutting than with the standard balloon catheter. In chronic experiments, the site of the incision was recognizable as a broad, shallow crater. Figures 4A and B show that 14 days after intervention, the luminal surface of the cuts is endothelialized. The base of the wound is filled with smooth muscle cells. There is no inflammatory cell infiltration present. After angioplasty with the cutting balloon there was no intimal proliferation outside the cut area compared with an 8.7% proliferative area (as a percentage of the media) after angioplasty with the standard balloon. Figure 5 compares the angiographic vessel diameter after dilatations with the standard and cutting balloons. The diameters immediately after dilatation with the cutting and standard balloons were greater than the vessel sizes before angioplasty by 11 (standard error of the mean f 4) and 13% ( f 2) respectively. The diameter of the arteries after angioplasty with the standard balloon decreased to 5% above the original diameter within 1 hour, and decreased below baseline at sacrifice by 5%, whereas the vessel diameter remained 9% (standard error of the mean f 3) greater than the original diameter at that time after angioplasty with the cutting balloon.
In this report we describe a new concept of angioplasty based on the premise that sharp incisions repair with less scar formation and remain more circumscribed than wounds created by tears4 We produced sharp, longitudinal surgical incisions directed radially into the media with our cutting balloon catheter. The histological damage outside the cut area was less after dilation with the cutting than with standard balloon. This study also demonstrated an excellent healing process with complete reendothelialization of the surface at 14 days without
I FIGURE 5. Angiiraphic after angioplasty with cutting banWnS. The
T
151
1
vessel size standard and y axis
shows
per-
ceiltlk!changesefv~sixe.Thex
axis shows time when measurements wefe obtained. Percentage of dilatation was similar with both types ol interventbns. After angleplasty with cenventienal balben, angiegraphic vessei di-Si~~Withill
1 hour, whereas after angtoplasty with cutting balloon it remains practically the same, even at 14 days. N.S. = not siw. t. l
MS. PC.01
BRIEF REPORTS
1251
combining cutting and dilation are that: (1) by cutting deeply into the medial layer restitution of the vascular tone is decreased, thereby decreasing dilatation time and pressure; (2) with the sharp, surgical incision, less medial smooth muscle cell stretch may induce less growth factor expression and, thus, less intimal proliferation; and (3) the vascular injury is localized to the incision site. 1. Mizuno K, Jurita A, Imazeki N. Pathologic finding after percutaneous transluminal angioplasty. 5r Heart J 1984;18:476-484.
1252
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
2. Austin GE, Ratliff NB, Hollman J, Tabei S, Phillips DF. Intimal proliferation of smooth muscle cells as an explanation for recurrent coronary artery stenosis after percutaneous transluminal angioplasty. d Am Coil Cardiol1985;6:369-375. 3. Waller BF. “Crackers, breakers, stretchers, drillers, scrapers, shavers, burners, welders and melters”-the future treatment of atherosclerotic coronary artery disease? A clinical-morphologic assessment. J Am Coil Cardiol 1989;13: 969-987. 4. Medden JW, Arem AJ. Wound healing: biologic and clinical features, In: Sabiston DC, ed. Textbook of Surgery. Philadelphia: Saunders, 1986:193. 5. Walker LN, Ramsay MM, Bowyer DE. Endothelial healing following defined injury to rabbit aorta. Atherosclerosis 1983;47:123-130. 6. Steele PM, Chesebro JH, Stanson AW, Holmes DR, Dewanjee MK, Badimon L, Fuster V. Balloon angioplasty. Natural history of the pathophysiological response to injury in a pig model. Circ Res 1985;57:105-112.
NOVEMBER
1, 1991