Handbook of Advanced Interventional Cardiology - part 5 potx

252 Practical Handbook of Advanced Interventional Cardiology Rescue angioplasty for failed thrombolysis: Since clinical signs and electrocardiographic data of reperfusion are not precise, the guidelines of the ACC/AHA task force suggest that catheterization be performed in any thrombolytic patients with ongoing chest pain or hemodynamic instability, or in asymptomatic patients who are less than 12 hours of symptom onset with persistent ST elevation, after 90 minutes of thrombolytic therapy. 37 However, the patients who require rescue angioplasty due to failed thrombolysis remained at increased risk for reocclusion, because they possibly had higher resistance to pharmacologic reperfusion, large throm- bus burden or platelet-rich thrombi, factors unfavorable to the performance of mechanical intervention. Rescue PCI should be performed on high-risk lesion (>75%) with TIMI of 2 or less. The mortality of patients who failed rescue PTCA was high, in the 30% range, while it was only 7–11% in patients with persistent occluded IRA treated conservatively. There was no indication for PCI of the IRA if the TIMI fl ow is 3 following lytic treatment. However, there are exceptions, which include the patients with high risk of reocclusion or severe complications if there is occlusion of the IRA, and patients with >90% residual stenosis, prior MI, decreased LV ejection fraction, or multivessel disease. Non-IRA lesion: Stenosis of non-IRA vessels should not be treated by emergent PCI unless there is evidence of persistent ischemia or cardiogenic shock after adequate reperfusion of the IRA. PCI for saphenous vein graft: Pa tients with prio r coronary artery bypass grafting who present with AMI are equally likely to occlude native vessels and bypass grafts, although LIMA grafts have a lower rate of stenosis. AMI after CABG usually affects smaller territories and presents with milder symptoms. 36 In comparison to native vessels, SVG thrombosis typically has a suboptimal response to fi brinolytic therapy. Vein grafts lack side branch vessels that would normally de- liver the fi brinolytic agent to the site of occlusion. 37 In the case of mechanical intervention, because of the large size of the SVGs and high thrombotic burden, there is a signifi cant risk of distal embolization. In the PAMI-2 trial the overall in-hospital and 6-month mortality of patients with prior CABG was higher compared with patients without prior CABG. Patients with CABG had lower rates of TIMI-3 fl ow after PCI, and mechanical intervention was less frequently attempted. 38 Recently, catheter-based fi lter devices were found to be effective in preventing distal embolization in primary PCI of SVG lesions. Left main PCI in AMI: In a small study by Marso et al., in which 40 patients with AMI due to LM occlusion were treated with emergent PCI, the angiographic success rate was 88%. In-hospital mortality was 55%, and CABG was performed in 10% of patients. The 12-month mortality after left main PTCA Acute ST-elevation Myocardial Infarction 253 with stenting was high (58%) but substantially lower than PTCA without stenting (78%; P <0.05). 39 All hospital deaths were a result of cardiogenic shock. Therefore, although PCI strategy for AMI from left main disease is feasible, short- and long-term mortality is high. 40 I f L M o c c l u s i o n i s a r e s u l t o f a o r t i c dissection, then PCI of the LM may be performed as a bridge toward hemodynamic stability before proceeding with defi ni- tive surgery. 41 CONCLUSION Despite numerous advances in management of STEMI, the treatment goal remains unchanged: prompt restoration of patency in the infarct-related artery (IRA) can reduce myocardial infarct size, minimize myocardial damage, preserve ventricular function, and signifi cantly reduce mortality. The dominant and benchmark reperfusion strategy worldwide remains fi brinolytic therapy. However, rapid restoration of patency by catheter-based percutaneous intervention can result in excellent outcomes, 42 and the use of an early interventional strategy continues to increase. If experienced operators are available at an institution with a large procedure volume, and if the interval between door and balloon (reperfusion) is less than 120 minutes, primary PCI has been shown to be superior to pharmacologic reperfusion, mostly by virtue of reducing recurrent MI and ICH. This benefi t is mitigated by a number of factors and adjunct therapies, including glycoprotein 2b3a receptor antagonists, antithrombotics and antiplatelet agents, and low-dose fi brino- lytics. These agents help to increase the opening rate of the IRA, increase tissue perfusion, and sustain patency after the acute event. 43 Female sex, age >65, presence of left bundle branch block, and advanced time of presentation (>12 hours) represent high-risk factors, and early mechanical intervention should be considered in these patients even in the absence of chest pain. In subgroups where PCI is comparable to thrombolysis in reducing mortality, mechanical reperfusion may still h a v e a n i m p o r t a n t r o l e i n p r e v e n t i o n o f v e n t r i c u l a r r e m o d e l i n g , dilatation, and dysfunction that could impact the long-term prognosis of patients with AMI. REFERENCES 1. Keyt BA, Paoni NF, Refi no CJ et al. A faster-acting and more potent form of tissue plasminogen activator. Proc Natl Acad Sci USA 1994; 91: 3670–4. 2. Single-bolus tenecteplase compared with front-loaded alteplase in acute myocardial infarction: the ASSENT-2 double-blind randomised trial. Assessment of the Safety and 254 Practical Handbook of Advanced Interventional Cardiology Effi cacy of a New Thrombolytic Investigators. Lancet 1999; 354: 716–22. 3. Sinnaeve P, Granger C, Barbarsh G. Single bolus tenecteplase and front-loaded alteplase remain equivalent after one year: follow-up results of the ASSENT-2 trial. Eur Heart J 2000; 21: 481. 4. The TIMI Study Group. The Thrombolysis in Myocardial In- farction (TIMI) trial. Phase I fi ndings. N Engl J Med 1985; 312. 5. Gibson CM, Cannon CP, Daley WL et al. TIMI frame count: a quantitative method of assessing coronary artery fl ow. Cir- culation 1996; 93: 879–88. 6. Cannon CP, Braunwald E. GUSTO, TIMI and the case for rapid reperfusion. Acta Cardiol 1994; 49: 1–8. 7. Gibson CM, Murphy SA, Rizzo MJ et al. Relationship between TIMI frame count and clinical outcomes after thrombolytic administration. Thrombolysis In Myocardial Infarction (TIMI) Study Group. Circulation 1999; 99: 1945–50. 8. Gibson CM, Cannon CP, Murphy SA et al. Relationship of TIMI myocardial perfusion grade to mortality after administration of thrombolytic drugs. Circulation 2000; 101: 125–30. 9. Gibson CM, Murphy SA, Barron HV. Relation of epicardial blood fl ow and myocardial perfusion to long term outcomes 2 years following thrombolysis in AMI: A TIMI 10B substudy. Circulation 2000; 102 : 435. 10. Gibson CM. How to do the Corrected TIMI Frame Count. Instruction to the investigators of the TIMI trials. www.timi.tv accessed May 28 2003. 11. Stone G, Grines C. Beyond primary PTCA: New ap- proaches to mechanical reperfusion therapy in AMI. In: Stack RS, Roubin GS, O’Neill W, eds. Interventional Cardiol- ogy Medicine, Principles and Practice. Churchill Livingstone, 2002: 301–62. 12. Wang HJ, Kao HL, Liau CS, Lee YT. Export aspiration catheter thrombosuction before actu al ang ioplast y in pr imar y coronary intervention for acute myocardial infarction. Cathet Cardiovasc Interv 2002; 57: 332–9. 13. Beran G, Lang I, Schreiber W et al. Intracoronary throm- bectomy with the X-Sizer catheter system improves epicardial fl ow and accelerates ST-segment resolution in patients with acute coronary syndrome: a prospective, randomized, controlled study. Circulation 2002; 105 : 2355–60. 14. Ross AM, Coyne K, Reiner J. Very early PTCA of IRA with TIM I fl ow is assoc i ate d with improve d clin i cal o u tcome s. J Am Coll Cardiol 2000; 35: 403. 15. Lansky A, Stone G, Mehran R. Impact on baseline TIMI fl ow on outcome after primary stenting versus primary PTCA in AMI: Results of the PAMI trials. J Am Coll Cardiol 2000; 35: 368A. 16. Wharton TP, Jr, McNamara NS, Fedele FA, Jacobs MI, Gladstone AR, Funk EJ. Primary angioplasty for the treatment of acute myocardial infarction: experience at two community Acute ST-elevation Myocardial Infarction 255 hospitals without cardiac surgery. J Am Coll Cardiol 1999; 33: 1257–65. 17. Grines CL, Cox DA, Stone GW et al. Coronary angioplasty with or without stent implantation for acute myocardial infarction. Stent Primary Angioplasty in Myocardial Infarction Study Group. N Engl J Med 1999; 341: 1949–56. 18. Stone GW, Marsalese D, Brodie BR et al. A prospective, randomized evaluation of prophylactic intraaortic balloon counterpulsation in high risk patients with acute myocardial infarction treated with primary angioplasty. Second Primary Angioplasty in Myocardial Infarction (PAMI-II) Trial Investiga- tors. J Am Coll Cardiol 1997; 29: 1459–67. 19. Quinn MJ, Plow EF, Topol EJ. Platelet glycoprotein IIb/IIIa inhibitors: recognition of a two-edged sword? Circulation 2002; 106 : 379–85. 20. Kern MJ, Meier B. Evaluation of the culprit plaque and the physiological signifi cance of coronary atherosclerotic nar- rowings. Circulation 2001; 103: 3142–9. 21. The PRISM Investigators. A comparison of aspirin plus tirofi ban with aspirin plus heparin for unstable angina. Plate- let Receptor Inhibition in Ischemic Syndrome Management (PRISM). N Engl J Med 1998; 338: 1498–505. 22. The PRISM-PLUS Investigators. Inhibition of the platelet glycoprotein IIb/IIIa receptor with tirofi ban in unstable angina and non-Q-wave myocardial infarction. Platelet Receptor In- hibition in Ischemic Syndrome Management in Patients Lim- ited by Unstable Signs and Symptoms (PRISM-PLUS) Study Investigators. N Engl J Med 1998; 338: 1488–97. 23. The PURSUIT Trial Investigators. Inhibition of platelet glycoprotein IIb/IIIa with eptifi batide in patients with acute coronary syndromes. The PURSUIT Trial Investigators. Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy. N Engl J Med 1998; 339: 436–43. 24. Simoons ML. Effect of glycoprotein IIb/IIIa receptor block- er abciximab on outcome in patients with acute coronary syndromes without early coronary revascularisation: the GUSTO IV-ACS randomised trial. Lancet 2001; 357: 1915–24. 25. The PARAGON Investigators: Platelet IIb/IIIa Antago- nism for the Reduction of Acute coronary syndrome events in a Global Organization Network. International, randomized, controlled trial of lamifi ban (a platelet glycoprotein IIb/IIIa in- hib itor), h eparin, or b oth in uns table angina. Circulation 1998; 97: 2386–95. 26. Topol EJ. Reperfusion therapy for acute myocardial infarction with fi brinolytic therapy or combination reduced fi brinolytic therapy and platelet glycoprotein IIb/IIIa inhibition: the GUSTO V randomised trial. Lancet 2001; 357: 1905–14. 27. Escobar J, Marchant E, Fajuri A. Stenting could decrease coronary blood fl ow during primary angioplasty in acute myocardial infarction. J Am Coll Cardiol 1999; 33: 361A. 256 Practical Handbook of Advanced Interventional Cardiology 28. Lincoff AM, Topol EJ. Illusion of reperfusion. Does any- one achieve optimal reperfusion during acute myocardial infarction? Circulation 1993; 88: 1361–74. 29. Gibson CM, Ryan KA, Murphy SA et al. Impaired coronary blood fl ow in nonculprit arteries in the setting of acute myocardial infarction. The TIMI Study Group. Thrombolysis in myocardial infarction. J Am Coll Cardiol 1999; 34: 974–82. 3 0. Garbo R , Stef fen i no G, Dell avalle A , Rus s o P, Mei nard i F. Myocardial infarction with acute thrombosis of multiple major coronary arteries: a clinical and angiographic observation in four patients. Ital Heart J 2000; 1: 824–31. 31. Leosco D, Fineschi M, Pierli C et al. Intracoronary se- rotonin release after high-pressure coronary stenting. Am J Cardiol 1999; 84: 1317–22. 32. Mahaffey KW, Puma JA, Barbagelata NA et al. Adenos- ine as an adjunct to thrombolytic therapy for acute myocardial infarction: results of a multicenter, randomized, placebo-controlled trial: the Acute Myocardial Infarction STudy of ADenos- ine (AMISTAD) trial. J Am Coll Cardiol 1999; 34: 1711–20. 33. Late breaking trials: AMISTAD-2. In: Scientifi c Session of the American College of Cardiology. Atlanta, GA; 2002. 34. Platelet glycoprotein IIb/IIIa receptor blockade and low- dose heparin during percutaneous coronary revascularization. The EPILOG Investigators. N Engl J Med 1997; 336: 1689–96. 35. The ASSENT 3 Investigators. Effi cacy and safety of tenecteplase in combination with enoxaparin, abciximab, or un- fractionated heparin: the ASSENT-3 randomised trial in acute myocardial infarction. Lancet 2001; 358: 605–13. 36. Grines CL, Booth DC, Nissen SE et al. Mechanism of acute myocardial infarction in patients with prior coronary artery bypass grafting and therapeutic implications. Am J Cardiol 1990; 65: 1292–6. 37. Reiner JS, Lundgren CF, Kopecky SL. Ineffectiveness of thrombolysis for AMI following vein graft occlusion (abst). Circulation 1996; 94: I-570. 38. Stone GW, Brodie BR, Griffi n JJ et al. Clinical and angiographic outcomes in patients with previous coronary artery bypass graft surgery treated with primary balloon angioplasty for acute myocardial infarction. Second Primary Angioplasty in Myocardial Infarction Trial (PAMI-2) Investigators. J Am Coll Cardiol 2000; 35: 605–11. 39. Marso SP, Steg G, Plokker T et al. Catheter-based reperfusion of unprotected left main stenosis during an acute myocardial infarction (the ULTIMA experience). Unprotected Left Main Trunk Intervention Multi-center Assessment. Am J Cardiol 1999; 83: 1513–17. 40. Neri R, Migliorini A, Moschi G, Valenti R, Dovellini EV, Antoniucci D. Percutaneous reperfusion of left main coronary disease complicated by acute myocardial infarction. Cathet Cardiovasc Interv 2002; 56: 31–4. Acute ST-elevation Myocardial Infarction 257 41. Barabas M, Gosselin G, Crepeau J, Petitclerc R, Cartier R, Theroux P. Left main stenting – as a bridge to surgery – for acute type A aortic dissection and anterior myocardial infarction. Cathet Cardiovasc Interv 2000; 51: 74–7. 42. Timmis G, Timmis S. The restoration of coronary blood fl ow in acute myocardial infarction. J Interv Cardiol 1998; 11: S9-S17. 43. Smith SC Jr, Dove JT, Jacobs AK et al. ACC/AHA guidelines for percutaneous coronary intervention: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1993 Guidelines for Percutaneous Transluminal Coronary Angioplasty). J Am Coll Cardiol 2001; 38: 2239i. 259 *Basic; **Advanced; ***Rare, exotic, or investigational. From: Nguyen T, Hu D, Saito S, Grines C, Palacios I (eds), Practical Handbook of Advanced Interventional Cardiology, 2nd edn. © 2003 Futura, an imprint of Blackwell Publishing. Chapter 13 Bifurcation Lesions Samuel J Shubrooks, Jr General overview Technical considerations Balloon angioplasty (PTCA) **Double balloon angioplasty **Selection of guides in double balloon technique **Which branch to wire fi rst? Directional coronary atherectomy (DCA) The CAVEAT trial **Indications and contraindications **Selection of cutter and guide for DCA **Wiring technique **Cutting technique **DCA in side branch Rotational atherectomy **Strategies for rotational atherectomy Stenting **Stenting of main vessel alone **Interventions of side branch **Crossing a stent at its side strut **T stenting **“Kissing” stents **V stenting **Y or “trousers” stenting **“Culotte” stenting **True bifurcated stents Practical considerations 260 Practical Handbook of Advanced Interventional Cardiology GENERAL OVERVIEW Bifurcation lesions present some of the most diffi cult chal- lenges in percutaneous coronary interventions. Treatment of such lesions is associated with reduced procedural success and increased complications as well as increased restenosis risk. Several factors are likely to contribute to these poorer outcomes. Plaque and endothelial characteristics of ostial lesions appear to lead to increased recoil and increased risk of dissection with compromise of side branches and /or main vessel. Intervention in either branch of a bifurcation lesion frequently leads to “snow plowing” with shifting of plaque, com- promising the opposing branch. Because of these concerns, such lesions are often treated less aggressively, leading to greater residual stenosis and therefore greater restenosis. TECHNICAL CONSIDERATIONS True bifurcation lesions are generally considered to be those in which a single lesion involves both main vessel and branch vessel with greater than 50–70% stenosis in both. Lesions in which a side branch originates from within a signifi - cant lesion in the main vessel, but without apparent signifi cant disease in the branch itself, may also be considered as bifurcation lesions since the branch vessel may require treatment as well. Situations in which a branch without apparent disease originates near, but not within, a lesion in a main vessel rarely require treatment of the branch vessel. However, treatment of branch vessels with severe ostial lesions may, at times, result in compromise of the main vessel, requiring bifurcation intervention. Because treatment of bifurcation lesions with balloon angioplasty alone frequently gives suboptimal results, experience has developed in the use of other technologies, including directional coronary atherectomy (DCA), rotational atherectomy, and stenting. These newer devices generally provide improved procedural results, though with the potential of increased complications, with continuing uncertainty as to the long-term outcomes. In our laboratory, we studied 70 con- secutive patients with true bifurcation lesions, 30 treated with conventional PTCA alone and 40 with either DCA or rotational atherectomy with adjunctive PTCA. 1 Use of atherectomy re- sulted in lower immediate residual stenosis in both the main and the branch vessels and a decreased 1-year target vessel revascularization (TVR) (28% vs 53%). Independent predictors of need for TVR were side branch diameter >2.3 mm, lesion length, and treatment with PTCA alone. This experience suggests that more aggressive debulking techniques should be considered for larger side branches, although they may be of no benefi t for smaller ones. Bifurcation Lesions 261 BALLOON ANGIOPLASTY (PTCA) D i l a t a t i o n o f m a i n v e s s e l o n l y : A strategy of dilatation of the main ves sel onl y may be suitabl e if the si de branch has no apparent ostial disease, or if there is no more than moderate disease that does not require treatment, with the side branch originating adjacent to, but not within, the main vessel lesion. Under these circumstances, risk of side branch compromise is minimal, and if it occurs, it can be easily treated. 2 This strategy may also be suitable if an involved side branch is of small caliber and diffusely diseased such that loss would have little, if any, clinical signifi cance. Loss of septal branches, except those of very large caliber, rarely results in adverse clinical outcomes, probably because of collateral septal supply. Unless the artery is very large with excellent fi nal MLD after POBA, it is diffi cult to justify POBA alone because of lower restenosis rates with atherectomy and bare stenting. Treatment of main vessel and side branch using a double wire technique: If a branch arises from within the lesion in the main vessel, there is an increased risk of branch occlusion with dilatation of the main vessel alone, with a reported incidence of 38–41% if there is greater than 50–70% stenosis of the branch origin. 2–4 This may occur as a result of plaque shifting, dissection involving the branch origin, or embolization. Therefore, side branches considered to be clinically important, and particularly those with ostial disease, should be treated as well as the main vessel. Follow-up of patients treated with PTCA of both branches have been reported as having an angiographic restenosis rate at 6 months of 37% 5 and a clinical restenosis rate of 42%. 4 TECHNICAL TIPS **Double balloon angioplasty: When treatment of the side branch is anticipated, a double wire technique should be used with a guidewire advanced into each branch, be- ing careful that the wires do not twist during manipulation. Although some operators use a triport hemostasis valve, both wires and balloons can be easily advanced through the same opening of a single hemostasis Y adaptor. The main vessel and side branch can be sequentially dilated using either rapid exchange or over-the-wire dilating catheters. Sequential dilatations will permit the use of a smaller guiding catheter, but this strategy frequently results in shifting of plaque toward the undilated vessel with failure to achieve optimal results in both vessels. A more optimal result can usually be obtained using a “kissing balloon” strategy with simultaneous dilatations in both branches (Figure 13-1). Since both balloons will infl ate together in the main vessel proximal to the bifurcation, it is important that these balloons not be oversized for the vessel diameter or infl ated [...]... both of the branches but leaves uncovered any disease in the bifurcation itself or proximal to the bifurcation.10–12 272 Practical Handbook of Advanced Interventional Cardiology Figure 1 3-4 : Types of bifurcation stenting (A) T stenting with the right angle takeoff of side branch providing good coverage of lesion (B) T stenting with acute angle takeoff of side branch leaving an unstented gap at origin of. .. Saito S, Grines C, Palacios I (eds), Practical Handbook of Advanced Interventional Cardiology, 2nd edn © 2003 Futura, an imprint of Blackwell Publishing 279 280 Practical Handbook of Advanced Interventional Cardiology **Cause of failure of PCI in LIMA graft **PCI in the subclavian artery Conclusions GENERAL OVERVIEW Patients who experience recurrence of ischemia after coronary artery bypass graft surgery... Because of severe ostial involvement of the diagonal, rotational atherectomy was first performed with a 1. 7 5- mm burr, followed by “kissing” balloon inflations with a 2 . 5- mm balloon in the diagonal and a 3 . 5- mm balloon in the LAD, followed by placement of a 3 . 5- mm stent in the LAD Because of the initial atherectomy treatment of the branch, there was no compromise of this following stenting in the LAD... usually be accomplished with low-inflation pressures (Figure 1 3-3 ) 268 Practical Handbook of Advanced Interventional Cardiology Figure 1 3-3 : Severe ostial stenosis of the circumflex artery with ostial involvement of a large marginal branch (not well seen) PTCA alone or stenting into either branch would likely have compromised the opposing branch Because of the ostial location of the lesion, PTCA would have... stage, dilation of the distal anastomosis can be accomplished with little morbidity and good long-term patency (80–90%) Dilation of the proximal and mid-segment of the vein graft was highly successful at 90%, with a low rate of mortality (1%), Q-wave MI, and CABG (2%) The rate of non-Q-wave MI was 13% The length of time since surgery was an important factor for restenosis, as was the location of the lesion... incidence of side branch occlusion if main vessel stenting alone is performed (Figure 1 3-2 ) TECHNICAL TIP **Strategies for rotational atherectomy: A guiding catheter of sufficient size to permit passage of the largest anticipated burr should be used A Rotablator wire is 266 Practical Handbook of Advanced Interventional Cardiology Figure 1 3-2 : Severe LAD/diagonal bifurcation lesion Because of severe...262 Practical Handbook of Advanced Interventional Cardiology Figure 1 3-1 : Severe lesion in proximal LAD involving first diagonal branch PTCA of LAD alone would likely have compromised the diagonal A 3 . 5- mm balloon in the LAD and a 3.0-mm balloon in the diagonal were inflated simultaneously, giving a good final result in both branches (Continued) to high pressures The dilating diameter of the two balloons... 1320 5 13 Aliabadi D, Tilli FV, Powers TR et al Incidence and angiographic predictors of side branch occlusion following high-pressure intracoronary stenting Am J Cardiol 1997; 80 : 994–7 14 Fischman DL, Savage MT, Leon MB et al Fate of lesionrelated side branches after coronary artery stenting J Am Coll Cardiol 1993; 22 : 1641–6 278 Practical Handbook of Advanced Interventional Cardiology 15 Ormiston... the wire is by having a steering device of a different color on each wire DIRECTIONAL CORONARY ATHERECTOMY (DCA) The removal of plaque with DCA has potential advantages in treatment of bifurcation lesions in decreasing the amount 264 Practical Handbook of Advanced Interventional Cardiology of plaque shifted toward side branches, possibly decreasing the incidence of dissection, and providing a larger,... stenting of the branch The balloon is then removed and the second stent advanced over the branch wire and positioned so as to cover the branch lesion and widely overlap the proximal portion of the previously placed stent The guidewire in the first branch, having been pulled 276 Practical Handbook of Advanced Interventional Cardiology back prior to deployment of the second stent, is then readvanced across . acute myocardial infarction. J Am Coll Cardiol 1999; 33: 361A. 256 Practical Handbook of Advanced Interventional Cardiology 28. Lincoff AM, Topol EJ. Illusion of reperfusion. Does any- one achieve. has potential advantages in treatment of bifurcation lesions in decreasing the amount Figure 1 3-1 (Continued) 264 Practical Handbook of Advanced Interventional Cardiology of plaque shifted toward. ations with a 2 . 5- mm balloon in the diagonal and a 3 . 5- mm balloon in the LAD, followed by placement of a 3 . 5- mm stent in the LAD. Because of the initial atherectomy treatment of the branch,