Rotational coronary atherectomy after unsuccessful coronary balloon angioplasty

Rotational Coronary Atherectomy After Unsuccessful Coronary Balloon Angioplasty Walter C. Brogan, III, MD, Phil, Jeffrey J. Popma, MD, August0 D. Pichard, MD, Lowell F. Satler, MD, Kenneth M. Kent, MD, Gary S. Mintz, MD, and Martin B. Leon, MD The clinical and an@ographic outcome of patients undergoing rotational coronary atherectomy after unsuccessful balloon angioplasty was evaluated using quantitative angrographic methods to pro vide insight into this procedure’s mechanism of benefit. During the study period, 41 patients (50 lesions) were referred for rotational atherectomy after standard balloon angioplasty was unsuc+ cessful. After rotational atherectomy, percent diameter stenosis was reduced from 72 + 14% to 41 & 16% (p ~0.001); adjunct balloon angioplasty was performed in 44 lesions (66%), resulting in a 25 + 17% final diameter stenosis (p ~0.001). The acute gain in minimal lumen diameter was 1.20 f 0.59 mm. In lesions needing adjunct balloon dilatation, lesion stretch was 73 f 27%, and elastic recoil was 22 -C l6%, with no variation by etiology of the initial balloon failure. Overall angiographic success (450% residual diameter stenosis) was obtained in 49 lesions (96%) Procedural success, defined as ~50% residual diameter stenosis and the absence of major inhospital complications (death, Q-wave myocardial infarction or emergerr cy bypass surgery), was obtained in 37 of 41 pro cedures (90%); complications developed in 3 patients (7%), including 2 who needed emergency bypass surgery after development of delayed abrupt closure. It is concluded that rotational co~c onary atherectomy may be used in selected pzk tients when standard balloon angioplasty is unsuccessful. Its mechanism of benefit appears related, at least in part, to changes in plaque corn pliance resulting from partial atheroma ablation. (Am J Cardiol199~71:79&796)

From the Department of Internal Medicine (Cardiology Division), Washington Hospit .l Center, Washington, D.C. This research was supported by a grant from the Washington Cardiology Center Research Fund, Washington, D.C. Manuscript received August 26, 1992; revised manuscript received and accepted October 8, 1992. Address for reprints: Jeffrey J. Popma, MD, Angiographic Core Laboratory, Washington Hospital Center, Suite 4B-14, 110 Irving Street, N.W., Washington, D.C. 20010.

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n low-risk lesion subsets, standard balloon angioplasty frequently yields procedural success rates >90%.1$2 However, balloon angioplasty may be avoided in some patients because of unsuitable preprocedural coronary anatomy; in others, technical failure may result from the inability to adequately dilate the lesion.3,4 Most frequently, failure results from inability to cross the lesion with the balloon catheter or to fully inflate the balloon, once positioned, due to lesion rigidity.3,4 In some cases, immediate elastic recoil results in a signiticant residual stenosis after balloon deflation, despite adequate lesion dilatation. These factors may contribute to the lower angiographic success rates using balloon angioplasty in lesions with excess length, calcium or ostial location and in those with severe angulation or proximal vessel tortuosity. W7 Rotational coronary atherectomy has been successfully used in patients in whom standard balloon angioplasty was unsuccessfuL8-” By partially ablating the fibrocalcitic plaque,12 rotational atherectomy may result in an acceptable stand-alone result or, by altering plaque compliance, render the lesion more amenable to adjunct balloon dilatation and reduce the magnitude of immediate elastic recoil. However, a quantitative analysis of dimensional changes resulting from rotational coronary atherectomy after unsuccessful coronary angioplasty and a description of its potential effects on plaque compliance have been lacking. Therefore, we reviewed our experience with this procedure using quantitative angiographic methods. METHODS Patient selection: Rotational coronary atherectomy was performed in 519 patients (685 lesions) between June 1990 and June 1992. Of these patients, 41 (8%) with 50 lesions were referred for rotational coronary atherectomy after 21 attempt using balloon angioplasty was unsuccessful due to: (1) lesion rigidity (inability to fully dilate the lesion) in 28 lesions (Figure l), (2) inability to cross the lesion with the balloon dilatation catheter despite guidewire positioning in 8 lesions, or (3) immediate elastic recoil despite adequate balloon expansion in 7 lesions. The mechanism of balloon failure could not be determined in 7 lesions. Rotational coronary atherectomy was considered after unsuccessful balloon angioplasty in ostial lesions, lesions with excessive calcium, eccentricity or angulation, or vessels ~3 mm in diameter. Lesions with extensive dissection, intimal flaps or abrupt closure after balloon angioplasty were not considered for rotational atherectomy. Lesions with restenosis after successful balloon angioplasty (~50% residual diameter stenosis) were not included in the analysis. Informed consent was obtained APRlL1,1993

from all patients before the procedure under the guidelines of the institutional review board. Atherectomy procedure: All patients were premedicated with aspirin and intravenous heparin (10,000 to 15,000 units), with additional heparin boluses as needed to maintain the activated clotting time >300 seconds. Intravenous (220 kg/mu-r) and frequent intracoronary (200 pg boluses) nitroglycerin were administered before and during the procedure to prevent coronary spasm. Depending on the largest anticipated burr size, an 8 to 1OFr guiding catheter was positioned in the coronary ostium by the femoral approach. After advancing a 0.009 inch guidewire across the lesion and positioning it freely in the distal vessel, rotational coronary atherectomy was performed using methods described in detail previously.13 Adjunct coronary balloon angioplasty was used if 230% residual stenosis persisted despite use of the largest appropriately sized burr or in the event of an angiographic complication (e.g., luminal irregularities or coronary dissection). Patient demographics: Hospital chart review was performed to obtain pertinent patient demographics and to identify in-hospital complications. A recent myocardial infarction was present if there was clinical, enzymatic or electrocardiographic evidence of myocardial necrosis within 6 weeks before atherectomy. Multivessel coronary artery disease was detined as 250% stenosis of branches of 22 major epicardial arteries. Major in-hospital complications were defined as death, Q-wave myocardial infarction and emergent coronary bypass surgery. Procedural success was delined as ~50% haI diameter stenosis and the absence of major in-hospital complications. Minor complications included recurrent ischemia (typical chest pain associated with electrocardiographic changes consistent with transmural

ischemia), abrupt vessel closure (Thrombolysis in Myocardial Infarction [TIMI] flow 0 or 1) and creature phosphokinase-Ml3 isoform increase >5 times the upper normal limit. Angiographic analysis: Standard morphologic criteria were used to assess lesion length (“shoulder to shoulder”), eccentricity and angulation.’ Ostial lesions were those within 3 mm of an epicardial coronary artery. Moderate lesion calcification was detined as mobile lumitral opacities demonstrated with cardiac motion. Severe calcification was defined as dense radioopacitication on both sides of the arterial lumen, which was generally found in the absence of cardiac motion. Selected end-diastolic cineframes before and after rotational atherectomy, and after adjunct balloon angioplasty if needed, were digitized using a cinevideo converter. Using the guiding catheter as the calibration standard, normal and minimal lumen diameters were determined using an automated, computer-assisted, edge detection algorithm. t4 In addition, the mean and minimal lumen diameters of the largest balloon used for adjunct dilatation were recorded. Acute gain (in mm) was defined as the increase in minimal lumen diameter immediately after the procedure.15 In lesions undergoing adjunct balloon dilatation 2 indexes of plaque compliance were used. Lesion stretch (%) was deiined as the difference between the diameter (mean and minimal) of the largest balloon and the preprocedural minimal lumen diameter, referenced to the normal vessel diameter.t6J7 Elastic recoil (%) was delined as the difference between the diameter (mean and minimal) of the largest balloon used and the postprocedural minimal lumen diameter, referenced to the normal vessel diameter.16J7 Statistical analysis: All continuous values were expressed as mean + 1 SD, and ordinal variables were ex-

FIGURE 1. A 50% stenosis of ostium of first diagonal branch of left anterior de scending artery (arrow; A) is treated with 2.5 mm balloon dilatation catheter. De spite Mation to 10 atm of pressure, re sidual waste is observed (6). After 2 inflations, 70% residual stenosis persisted (C). A 2 mm rotational atherectomy burr was used to treat residual stenosis (DJ After 2 passes, excellent Eta&alone result was obtained (Ej.

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I TABLE I Preprocedural Lesion Morphology in Lesions Undergoing Rotational Atherectomy After Unsuccessful Coronary Angioplasty (n = 50) Coronary artery Left anterior descending Left circumflex Right Location Ostial Proximal Mid Distal Eccentricrty Angulation 245” Lesion length 110 mm Lesion calcium Moderate Dense

TABLE II Acute Gain, Lesion Stretch and Elastic Recoil in Lesions Undergoing Rotational Atherectomy After Unsuccessful Balloon Angioplasty (n = 50) Reference diameter (mm) Overall acute gain Mean balloon (mm) Lesion stretch (%I (n = 28) Stretchan balloon diameter

20 (40) 13 (26) 17 (34) 7 (14) 16 (32) 24 (48) 3 (6) 36 (72) 18 (36)

Stretchminlmal

balloon diameter

Elastic recoil (%I (n = 28) Recoilmean balloon diameter RecoilmInimal

balloon diameter

2.43 t 0.54 1.19

s 0.60

2.50 2 0.48 73 ? 27 55 f 28 22 t 18 4 f 17

in 2 lesions, distal embolization occurred after rotational atherectomy of 2 lesions, and transient reduction in flow (TIMI flow ~3) was noted in 4 successfully treated le24 (48) 13 (26) sions. Acute gain, stretch and elastic recoil: After rotaNumbers in parentheses are percentages. tional atherectomy, minimal lumen diameter increased pressed as frequencies. Comparison between continuous from 0.67 f 0.39 to 1.52 + 0.50 mm (p 50% persisted branch, resulting in a posterior wall myocardial infarcafter rotational atherectomy. Adjunct balloon angioplas- tion. ty was used in 44 lesions (X8%), resulting in a linal perMinor complications included recurrent ischemia in cent diameter stenosis of 25 _+ 17% (p 2 times the upper normal (98%) after rotational atherectomy and adjunct balloon limit was noted in 4 patients, 2 in association with an angioplasty, if needed. The 1 patient in whom rotation- unsuccessful procedure. Creatine phosphokinase-MB al atherectomy was unsuccessful due to incomplete di- isoform elevation >5 times the upper normal limit was latation underwent uneventful, elective coronary bypass noted in 8 patients, including the 4 with recurrent ischesurgery. mia. In the 4 remaining patients, the enzyme increase After rotational atherectomy, coronary dissection (210 was of no clinical consequence. mm in length) developed in 3 lesions that were treated Late clinical outcome: During the 7.2 f 3.4 months with adjunct balloon dilatation. A residual intimal flap of follow-up, 9 of 37 patients (24%) developed recurwas observed in 5 lesions, coronary spasm was found rent symptoms. Angiographic follow-up was obtained in 796

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17 patients (46%). Restenosis (250% diameter stenosis) was documented in 6 patients (35%), 5 of whom were treated with coronary angioplasty. Coronary bypass surgery was performed in 2 patients who developed new disease during follow-up. Three patients with multivesse1 coronary artery disease died suddenly 1 to 7 months after rotational atherectomy; none of these had recurrent symptoms. DISCUSSION

Procedural success using standard balloon angioplasty is limited in complex lesion subsets’,* due in part to lesion rigidity, elasticity and inability to cross the stenosis with the balloon dilatation catheter.3,4 Therefore, alternative methods of percutaneous coronary angioplasty in these subsets have been used.8-11 In the present series of 50 lesions undergoing rotational coronary atherectomy after unsuccessful balloon angioplasty, a 90% procedural success rate was obtained. The lesions in this series were often complex, and included those with calcification (74%), eccentricity (72%), angulation (36%) and excessive length (22%). The benelicial effect of rotational atherectomy in lesions after unsuccessful balloon angioplasty may relate to changes in plaque compliance that render the lesion more amenable to balloon dilatation and reduce the degree of elastic recoil. Causes of unsuccessful balloon angioplasty: Despite marked development in operator experience and equipment design, balloon angioplasty is limited by the inability to successfully dilate some lesions. In the National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty Registry, balloon angioplasty was unsuccessful (inability to reduce diameter stenosis 220%) in 353 of 2,892 lesions (12.2%).3 Whereas 65% of these procedural failures were due to inability to pass the balloon angioplasty equipment across the stenosis, 35% resulted from inability to adequately dilate the lesion despite proper placement of the balloon dilatation catheter. A more recent series reported a much greater overall angiographic success rate 96.3% of 3,398 attempted lesions.4 However, almost 50% of the failures in this series were due to the inability to effectively dilate the lesion despite placement of the balloon catheter across the lesion. In the present series, patients were referred for rotational atherectomy after 21 unsuccessful balloon attempt; lesion rigidity (incomplete balloon expansion) was present in 56% of lesions and elastic recoil (complete balloon expansion) in 14%. In 18% of lesions, the balloon catheter could not be advanced across the lesion despite adequate wire positioning. Mechanism

of rotational

coronary

atherectomy:

Rotational coronary atherectomy may be useful in lesions in which standard balloon angioplasty was unsuccessful.8-11 The beneficial effect of rotational atherectomy in this lesion subset may be threefold. First, intracoronary ultrasound studies performed before and immediately after rotational coronary atherectomy have demonstrated a significant reduction in plaque mass resulting from partial atheroma ablation.12 Rotational atherectomy may thus improve lumen dimensions by removing fibrocalcific plaque and may be effective in le-

sions that have not responded adequately to balloon barotrauma (i.e., rigid lesions that do not fully dilate despite high balloon inflation pressures). Second, using a high-speed burr, rotational coronary atherectomy exerts its ablative effect before the burr advancement across the stenosis. This feature may be particularly useful in lesions that cannot be crossed using standard balloon catheters. Atherectomy burrs can traverse tortuous vessels, often with minimal damage to normal arterial wall, because of the flexibility of the coaxial shaft. Finally, rotational atherectomy may result in alterations of plaque compliance (see later), reducing the magnitude of elastic recoil after stand-alone rotational atherectomy and adjunct balloon dilatation, if required. Prior case reports,loJ l and single-9 and multicente? series have reported high procedural success rates and infrequent complications when rotational atherectomy was used in lesions with unsuccessful balloon angioplasty. In a series of 41 complex lesions reported by Rosenblum et a1,9rotational atherectomy was successful in 97.6% of lesions, suggesting that this technique may be the preferred method of revascularization in heavily calciEed, angulated and diffusely diseased lesions. In the present series, comprising 50 lesions with similar lesion complexity, a procedural success rate of 90% was obtained, again underscoring the usefulness of rotational coronary atherectomy in this lesion subset. Acute gain, sbetd~ d elastic recoil after rotation al atherectomy: Use of investigational angioplasty de-

vices yields larger improvements in initial coronary dimensions than does standard balloon angioplasty in case-matched controls.18 Moreover, despite the direct correlation between the acute gain and late lumen loss during follow-up, t9 late angiographic outcome (i.e., restenosis) appears to be associated with a suboptimal initial angiographic result after new device use15J9; the less the residual stenosis at the end of the procedure, the less the rate of late restenosis. In the present series, an acute gain of 1.2 mm was obtained using a combination of rotational atherectomy and adjunct balloon angioplasty, if needed. Given the relatively small reference vessel size (2.4 mm) and because all treated lesions had failed 21 prior attempt using balloon angioplasty alone, the 24% residual percent stenosis obtained using rotational atherectomy appears quite acceptable. Adjunct balloon angioplasty was used in most cases (88%) to treat a >30% residual diameter stenosis or, less frequently, an angiographic complication. When adjunct balloon angioplasty was used, indirect indexes of plaque compliance (i.e., lesion stretch and elastic recoil) suggested that the responsiveness of the lesion was altered as a result of rotational atherectomy. For example, in lesions with unsuccessful standard balloon angioplasty due to lesion rigidity, lesion stretch after rotational atherectomy (75%) was similar to that historically noted in lesions undergoing successful balloon angioplasty (66%). Moreover, in a small number of lesions with unsuccessful balloon angioplasty due to lesion elasticity, recoil after rotational atherectomy (11%) was similar to that noted after standard balloon angioplasty (31%) using similar quantitative angiographic methods (17). The data suggest that rotational coronary atherectomy

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exerts at least part of its beneficial effect on luminal dimensions by altering plaque compliance, rendering the lesion more responsive to adjunct balloon dilatation. In patients who have unsuccessful balloon angioplasty due to ineffective lesion dilatation, rotational coronary atherectomy is an effective method of revascularization, associated with high procedural success rates and infrequent complications. Given the complex anatomic subsets treated with rotational atherectomy in this series, expanded use of this device in certain high-risk lesion subsets including those with calcium, angulation and excessive length appears warranted.

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G. Clinical, physiologic, anatomic and procedural factors predictive of restenosis after percutaneous transluminal coronary angioplasty. J Am Coil Car& 1991; 18: 368-376. 7. Fitzgerald PJ, Ports TA, Yock PG. Contribution of localized calcium deposits to dissection after angioplasty. An observational study using intmvascular ultrasound. Circulation 1992;86:64-70. 8. Reisman M, Leon MB, Rivera I, Pichard AD, Satler LF, Buchbinder M. Use of the rotablator in patients with “undilatable” coronary lesions (abstr). Circulation 1991;84:&82. 9. Rosenblum J, Stertzer SH, Shaw RE, Hidalgo B, Hansell HN, Murphy MC, Myler RK. Rotational ablation of balloon angioplasty failures. Journal of Invasive Cardiology 1992;4:312-318. 10. Brown RIG, Penn AM. Coronary rotational ablation for unsuccessful angioplasty due to failure to cross the stenosis with a dilatation catheter. Cathet Cardiovasc Diagn 1992261 l&l 12. 11. Iyer SS, Hall P, Kiig JF, Dorms G. Successfal rotational coronary ablation following failed balloon angioplasty. Cathet Cardiovasc Diagn 1991;24:6568. 12. Kovach JA, Mintz GS, Pichard AD, Kent KM, Fay KG, Merritt AJ, Leon MB. Sequential intravascular ultrasound imaging charter&s mechanisms of lumen enlargement after rotational atherectomy (abstr). Circulation 1992;86:1-532. 13. Teirstein PS, Warth DC, Haq N, Jenkins NS, McGowan LC, Aubanel-Reidel P, Morris N, Ginsburg R. High speed rotational coronary atherectomy for patients with diffuse coronary a&ry disease. J Am Co11 Cmdiol 1991;18:1694-1701. 14. Man&i GBJ, Simon SB, McGiIlem MJ, LeFree MT, Friedman HZ, Vogel RA. Automated quantitative coronary arteriography: morphologic and physiologic validation in viva of a rapid digital a&graphic method. Circulation 1987;75: 452-460. 15. Kuntz RE, S&n RD, Levine MJ, Reis GJ, Diver DJ, Bairn DS. Novel approach to the analysis of restenosis after the use of three new coronary devices. .I Am CoN Car&l 1992;19:1493-1499. 16. Hermans WRM, Rensing BJ, Strauss BH, Sermys PW. Methodological problems related to the quantitative assessment of stretch, elastic recoil, and balloonartery ratio. Cathet Cardiovasc Diagn 199225: 174185. 17. Rensing BJ, Hermans WRM, Vos J, B&t KJ, Bossuyt P, Rutsch W, Sermys PW. Angiographic risk factors of luminal narrowing after coronary balloon angioplasty using balloon measurements to reflect stretch and elastic recoil at the dilatation site. Am J Cardiol 1992;69:584-591. 18. Muller DWM, Ellis SG, Dehowey DL, Top01 El. Quantitative an&graphic comparison of the immediate success of coronary angioplasty, coronary atherectomy and endoluminal stenting. Am J Cardiol 1990;66:938-942. 19. Popma JJ. De&are NB, Pinkerton CA, Wbitlow P, King SB, Ghazzal ZMB, Kereiakes DJ, Top01 EJ, Holmes DR, Ellis SG. Quantitative analysis of factors influencing late lumen loss and restenosis after directional coronary atherectomy. Am J Cardiol 1993;71:552-557.

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