Left Main Intervention Revisited: Early and Late Outcomeof PTCA and Stenting

Anoop Chauhan, * MD, Mohammad Zubaid, MD, Donald R. Ricci, MD,Christopher E. Buller, MD, Michael D. Moscovich, MD, Brenda Mercier, RN,

Rebecca Fox, PA, and Ian M. Penn, MB

We reviewed our experience with 28 unselected, consecutive patients undergoing leftmain coronary artery (LMCA) angioplasty who had been considered unsuitable forcoronary artery bypass graft surgery (CABG). Fourteen patients (50%) had a protectedLMCA circulation. Balloon angioplasty was performed in 11 patients (39.3%), and stentswere implanted in 17 patients (60.7%). The procedure was elective in 22 patients (78.6%)and acute in the setting of myocardial infarction/cardiogenic shock in 6 (21.4%). The meanfollow-up duration was 15.9 6 12 months. There were 5 early (before hospital discharge)and 4 late deaths (total 32.1%), 1 myocardial infarction (3.6%), 6 repeat angioplasties(21.4%), and 3 subsequent CABG (10.7%). All 5 early deaths occurred in patients withcardiogenic shock and unprotected circulation. The results of our study suggest thatwhen patients have prohibitive surgical risks, elective LMCA angioplasty and/or stentingmay be undertaken with a high procedural success rate. However, our data do not supportintervention in the presence of acute myocardial infarction/cardiogenic shock. Cathet.Cardiovasc. Diagn. 41:21–29, 1997. r 1997 Wiley-Liss, Inc.

Key words: angioplasty; left main stenosis; intracoronary stenting

INTRODUCTION

Significant left main coronary artery (LMCA) diseaseis the most serious manifestation of coronary atheroscle-rosis and is regarded as an absolute indication forcoronary artery bypass graft surgery (CABG). However,it is relatively uncommon, occurring in approximately5% of patients with chronic angina and 7% of patientswith a recent myocardial infarction [1,2]. The prognosisof medically treated patients with LMCA disease is verypoor, with a 3-year mortality rate of approximately 50%[3–7]. CABG may improve survival and remains thetime-tested procedure of choice in patients who aresurgical candidates [8–13].Percutaneous transluminal coronary angioplasty

(PTCA) of the LMCA has been technically feasible sincethe inception of coronary angioplasty, but its role in themanagement of patients with significant LMCA stenosishas been uncertain. PTCAof the LMCAcarries relativelyhigh rates of immediate and long-term morbidity andmortality [14]. Patients with LMCA stenosis can bedivided into 2 groups: protected (defined as the existenceof at least 1 patent bypass graft to the left anteriordescending or circumflex coronary artery) and unpro-tected. A recent report by an American College ofCardiology/American Heart Association Task Force re-gards PTCAof unprotected LMCAabsolutely contraindi-

cated [15]. Yet for critically ill patients in whom operativerisk is prohibitive, PTCA of unprotected LMCA is apotential revascularization procedure as a ‘‘last resort’’option. Previous reports of protected LMCA angioplastyindicate a primary success rate of 92–95%, and aprocedural mortality rate of 2–4% [14,16,17]. However,PTCA of unprotected LMCA stenoses remains a contro-versial issue due to increased procedural mortality andpoor long-term survival [14,18]. A small number ofLMCA stents has also been reported previously [19–22].We report procedural outcome and long-term follow-upof all patients who have undergone either protected orunprotected LMCA PTCA or stenting (acute or elective)at our institution. The procedural results and clinicaloutcome are compared in the various clinical subgroups.

METHODS

Patients

We retrospectively identified all patients who under-went acute and elective angioplasty of the LMCA from

*Correspondence to: Dr. Anoop Chauhan, Laurel InterventionalCardiology Research, 865 West 10th Avenue, Vancouver, BC,V5Z 1L7, Canada.

Received 6 September 1996; Revision accepted 3 December 1996

Catheterization and Cardiovascular Diagnosis 41:21–29 (1997)

r 1997 Wiley-Liss, Inc.

January 1, 1991, to December 31, 1995. This groupconstituted unselected, consecutive patients undergoingLMCAPTCAat our institution in whom CABG had beendeclined due to unfavourable clinical and/or angiographicfactors. The information on the patients was collectedfrom hospital charts, a PTCA database, and cineangio-graphic films. Follow-up information was obtained fromoutpatient charts and telephone interviews with patientsand family physicians.During the study period, LMCA angioplasty was

performed in 28 patients. Twenty-two patients (78.6%)underwent elective and 6 patients underwent acute LMCAangioplasty (defined as emergent LMCA PTCA for anevolving acute myocardial infarction and/or cardiogenicshock). Of 28 patients, 14 (50%) were protected and 14were unprotected. The baseline clinical variables areshown in Table I. Two patients had limiting stable angina,20 patients (71.4%) had unstable angina, and 6 (21.4%)had acute myocardial infarction, cardiogenic shock, andhemodynamic instability. All LMCA PTCAs were per-formed in patients with significant multiple vessel dis-ease, and 68% of procedures required multiple lesiondilatation. All patients had.70% stenosis in at least 2angiographic projections.

Angioplasty Procedure

The percutaneous transfemoral approach using a 9Fangioplasty sheath was used in all patients. Successful

PTCA was defined as a reduction to#50% luminaldiameter stenosis based on visual inspection in 2 or moreangiographic views in the absence of major complica-tions. Each patient received intravenous heparin (10,000U), and additional boluses were given as required duringthe procedure. An intra-aortic balloon pump (IABP) wasplaced in 8 patients (28.6%) as a prophylactic measure ordue to hemodynamic instability. In all patients the LMCAwas dilated first, and other significant stenoses within theleft coronary circulation were then dilated. Eleven pa-tients (39.3%) were treated with conventional balloonangioplasty, and 17 patients (60.7%) were treated withstents.

Statistical Analysis

Data are reported as mean6 standard deviation (SD)where applicable. Student’s t-test was used for continu-ous variables, and the chi-square test with continuitycorrection was used for categorical variables. AP valueof #0.05 was considered significant.

RESULTS

Clinical Outcome of All Patients (Table II)

The mean follow-up duration was 15.96 12 months(range 2–45 months). The procedural success rate was89.3%. There were 5 early deaths (defined as#30 days)(17.9%), and 4 late deaths (.30 days) (14.3%). All earlydeaths occurred before hospital discharge. The 4 latedeaths were cardiac deaths. The total mortality rate was32.1%. There was no early reintervention or CABG.However, 9 patients (32.1%) required late PTCA orCABG. Ten of 23 patients discharged from the hospitalunderwent repeat coronary angiography for recurrentsymptoms during the study period. Four of these patientshad a significant LMCA restenosis requiring repeatPTCA. In 2 patients there was a new significant stenosisrequiring PTCA. In 3 patients there was recurrence ofsymptoms with progression of disease (with LMCArestenosis in 1 patient), and surgeons agreed to performelective late CABG due to improvement in comorbidconditions. All 3 patients had previously undergoneCABG, had protected circulation at the time of theirLMCA PTCA, and had been turned down for repeatCABG because they were considered high risk.

Protected Versus Unprotected LMCAPTCA (Table III)

Of 28 patients undergoing LMCA PTCA, 14 (50%)had a protected circulation. IABP support was used in 5unprotected patients due to haemodynamic instability andin 3 patients prophylactically. There were no patients withacute myocardial infarction/cardiogenic shock in theprotected group, and all procedures were performed

TABLE I. Baseline Clinical Characteristics

Number of patients 28Follow-up (months) 15.96 12 (range 2–45)Age (years) 67.46 10 (range 48–89)Age.70 years 12 (42.9%)Males 24 (85.7%)Prior MI 19 (67.9%)Prior CABG 16 (57.1%)Prior PTCA 8 (28.6%)Hyperlipidemia 11 (39.3%)Hypertension 14 (50%)Diabetes mellitus 5 (17.9%)Smoker 12 (42.9%)Clinical presentationLimiting stable angina 2 (7.1%)Acute MI/cardiogenic shock 6 (21.4%)Unstable angina 20 (71.4%)

Protected left circulation 14 (50%)EF (%, n5 16) 44.36 17.7LVEDP 236 9.3Hospital stay (days) 3.86 2.6 (range 1–11)IABP support 8 (28.6%)Use of stents 17 (60.7%)Other lesion PTCA 19 (67.9%)

MI, myocardial infarction; CABG, coronary artery bypass graft surgery;PTCA, percutaneous transluminal coronary angioplasty; EF, ejectionfraction; LVEDP, left ventricular end diastolic pressure; IABP, intra-aorticballoon pump.

22 Chauhan et al.

without IABP support. Of the 14 patients in the protectedgroup, successful LMCA coronary artery dilatation wasachieved in all patients (100%). Of the 14 patients in theunprotected group, successful LMCA coronary arterydilatation was achieved in 11 patients (78.6%). A similarnumber of patients had LMCA calcification on fluoros-copy in both groups. Seven patients (50%) in the pro-tected group and 10 patients (71.4%) in the unprotectedgroup received a stent. Procedural complications in theunprotected group included 3 procedural deaths (21.4%)and nonfatal myocardial infarction in 1 patient (7.1%).There were 2 further early deaths (hospital discharge to30 days) in the unprotected group, providing an earlymortality rate of 35.7%. There were 2 additional latedeaths, providing a total mortality rate of 50% in theunprotected group. There were no early deaths and 2 latedeaths in the protected group, providing a total mortalityrate of 14.3% (P 5 not significant [NS]). The late PTCAor CABG rate was 42.8% in the protected group and21.4% in the unprotected group (P 5 NS). Figure 1demonstrates an example of successful LMCAPTCA in apatient with unprotected LMCA circulation.

PTCA Versus Stents (Table IV)

Of the 28 patients undergoing LMCA PTCA, 17(60.7%) received 1 or more stents. In 13 patients (46.4%),the decision of the operator had been to proceed as aprimary stent case; stents were used for suboptimal PTCAresult in 3 patients (10.7%) and for threatened closure in 1patient (3.6%). Twelve patients (70.6%) received a singlestent, 3 (17.6%) received 2 stents, 1 (5.9%) received 2.5stents, and 1 (5.9%) received 3 stents. The Palmaz-Schatzstent was used in all patients. Half stents were used in 4 of17 patients (23.5%), with the remainder of the patientsreceiving full stents. Intravascular ultrasound was notused in any patient. The number of patients havingcalcification in the LMCA on fluoroscopy was similar inthe 2 groups. The incidence of early and late deaths andthe need for repeat PTCAs and CABG were also similarin the 2 groups.There were 2 predischarge deaths (11.8%) in the stent

group. The first occurred in a 67-year-old woman who

TABLE II. Procedural and Clinical Outcome in All (n 5 28) LMCA PTCA

ProceduralProcedure-Discharge

Discharge-30 Days Latea Total

Death 3 (10.7%) 2 (7.1%) 0 4 (14.3%) 9 (32.1%)MI 1 (4.2%) 0 0 0 1 (3.6%)Repeat PTCA 0 0 0 6 (21.4%) 6 (21.4%)Repeat LMCAPTCA 0 0 0 4 (14.3%) 4 (14.3%)CABG 0 0 0 3 (10.7%) 3 (10.7%)aLate, hospital discharge to follow-up.LMCA, left main coronary artery; PTCA, percutaneous transluminal coronary angioplasty; MI,myocardial infarction; CABG, coronary artery bypass graft surgery.

TABLE III. Clinical Outcome in Protected and UnprotectedLMCA PTCA

Protected Unprotected

Number of patients 14 14Males 12 (85.7%) 12 (85.7%)Follow-up (months) 19.86 13.5

(range 4.5– 45)11.46 8.5(range 2–30)

Age 64.56 7.7 70.26 11.5Age.70 years 3 (21.4%) 9 (64.3%)Previous MI 10 (71.4%) 9 (64.3%)Previous PTCA 5 (35.7%) 3 (21.4%)Previous CABG 14 (100%) 2 (14.3%)*PTCA other lesions 10 (71.4%) 9 (64.3%)IABP support 0 8 (57.1%)*Acute MI/cardiogenic shock 0 6 (42.9%)**Unstable angina 13 (92.9%) 9 (64.3%)Stent use 7 (50%) 10 (71.4%)EF (%) 46.46 16.7a 43.56 20.2b

LVEDP 21.16 6.2 24.66 11.3LMCA calcification on fluoroscopy 8 (57.1%) 6 (42.9%)Duration of stay 3.46 2.4 4.36 2.8Clinical follow-upDeathPredischarge 0 5 (35.7%)Late 2 (14.3%) 2 (14.3%)Total 2 (14.3%) 7 (50%)

MIPredischarge 0 1 (7.1%)Late 0 0Total 0 1 (7.1%)

Repeat PTCAPredischarge 0 0Late 3 (21.4%) 3 (21.4%)Total 3 (21.4%) 3 (21.4%)

CABGPredischarge 0 0Late 3 (21.4%) 0Total 3 (21.4%) 0

*P5 0.03.** P5 0.07.an5 9.bn5 7.LMCA, left main coronary artery; PTCA, percutaneous transluminalcoronary angioplasty; MI, myocardial infarction; CABG, coronary arterybypass graft surgery; IABP, intra-aortic balloon pump; EF, ejection fraction;LVEDP, left ventricular end diastolic pressure.

Left Main Intervention 23

underwent multivessel angioplasty and stenting of theLMCA in the setting of impaired left ventricular function(ejection fraction,20%) and multisystem disease. Thispatient had been declined CABG and remained in thehospital with refractory recurrent angina. The secondoccurred in an 81-year-old man who underwent LMCAPTCA in a setting of multisystem failure, cardiogenicshock, and critical left main stenosis with an occluded

right coronary artery after having been declined CABG.In both cases, a successful angiographic result wasobtained and IABP support was used. However, thepatients remained in cardiogenic shock and died ofmultisystem failure at day 2 and day 4, respectively.There were 3 predischarge deaths (27.3%) in the PTCA

group. The first was in a 72-year-old man who wasdemonstrated to have an occluded right coronary artery

Fig. 1. Shallow RAO (right anterior oblique) projection (A) andspider view (B) demonstrating severe stenosis of distal left maincoronary artery involving the ostium of the left anterior descend-ing coronary artery and the ostium of the circumflex coronary

artery. C: Stenting of the distal left main and ostia of the LAD andCX using a kissing balloon high-pressure deployment tech-nique. D: Appearance in the spider view after successful stent-ing.

24 Chauhan et al.

and a 95% stenosis of the LMCA on elective coronaryangiography. The patient was stable throughout theprocedure and was returned to the holding room with aview to CABG. However, he developed ventricularfibrillation cardiac arrest requiring resuscitation and intu-bation. He was returned to the cardiac catheterizationlaboratory in an attempt to dilate the LMCA and insert aperfusion balloon so that he could go to surgery. Asuccessful dilatation was performed, but the patientdeveloped electromechanical dissociation; prolonged at-tempts to resuscitate were unsuccessful. The second deathoccurred in a 72-year-old man in whom PTCA of theLMCAwas performed in the setting of cardiogenic shockand acute anterior myocardial infarction with failedthrombolysis. An IABP was used before dilating a 95%stenosis of the distal LMCA. Emergency PTCA resultedin a satisfactory angiographic result but with slow antegradeflow. The patient then developed refractory ventricular fibril-lation from which he could not be resuscitated despiteprolonged aggressive attempts. The third death occurred in a77-year-old woman presenting with cardiogenic shock sev-eral hours after an abdominal operation. This patient wasfound to have critical LMCA disease with an occluded

right coronary artery. Emergency PTCA was performedwith IABPsupport. The patient developed electromechani-cal dissociation despite an angiographically successfulresult and was not able to be resuscitated.

Elective Versus Acute LMCA PTCA (Table V)

There were 6 patients (21.4%) in whom the procedurewas performed in the setting of an acute myocardialinfarction and/or cardiogenic shock. None of these pa-tients had a protected circulation, and IABP support wasused in 5 of these patients. In 5 of 6 acute patients(83.3%), the right coronary artery was occluded com-pared with 13 elective patients (59.1%) (P 5 NS). Therewere 5 deaths (83.3%) in this group before hospitaldischarge. Three of the 5 in whom the LMCA wassuccessfully dilated died in the cardiac catheterizationlaboratory of left ventricular pump failure and refractoryventricular dysrhythmias. The remaining patient remainswell with no further cardiac events. There were no earlydeaths and 4 late deaths (18.2%) in the elective group. Afurther 9 patients (40.9%) required repeat PTCA orCABG.

Elective Protected Versus Elective UnprotectedLMCA PTCA (Table VI)

Of the 22 patients who underwent elective LMCAPTCA, 14 (63.6%) had a protected circulation. Seven ofthe protected group (50%) received a stent compared withall 8 patients in the unprotected group. There were no

TABLE IV. Clinical Outcome in PTCA Versus Stents Patients

Stent PTCA

Number of patients 17 11Males 16 (94.1%) 8 (72.2%)Follow-up (months) 11.46 5.2

(range 2–22)25.36 15.4*(range 3–45)

Age 67.96 11.1 66.66 8.4PTCA other vessels 12 (70.6%) 7 (63.6%)Unprotected left circulation 10 (58.8%) 4 (36.4%)IABP support 6 (35.3%) 2 (18.2%)Acute MI/cardiogenic shock 3 (17.6%) 3 (27.2%)Unstable angina 14 (82.4%) 9 (81.8%)LMCA calcification on fluoroscopy 10 (58.8%) 4 (36.4%)Clinical follow-upDeathPredischarge 2 (11.8%) 3 (27.2%)Late 3 (17.6%) 1 (9.1%)Total 5 (29.4%) 4 (36.4%)

MIPredischarge 1 (5.9%) 0Late 0 0Total 1 (5.9%) 0

Repeat PTCAPredischarge 0 0Late 4 (23.5%) 2 (18.2%)Total 4 (23.5%) 2 (18.2%)

CABGPredischarge 0 0Late 0 3 (27.3%)Total 0 3 (27.3%)

*P5 0.02.PTCA, percutaneous transluminal coronary angioplasty; IABP, intra-aorticballoon pump; MI, myocardial infarction; LMCA, left main coronaryartery; CABG, coronary artery bypass graft surgery.

TABLE V. Clinical Outcome in AcuteVersus Elective LMCA PTCA

Acute Elective

Number of patients 6 22Protected 0 14 (63.7%)IABP support 5 (83.3%) 3 (13.6%)Patent RCA 1 (16.7%) 9 (40.9%)Clinical follow-upDeathPredischarge 5 0Late 0 4Total 5 (83.3%) 4 (18.2%)

MIPredischarge — 1 (4.5%)Late — 0Total — 1 (4.5%)

Repeat PTCAPredischarge — 0Late — 6Total — 6 (27.3%)

CABGPredischarge — 0Late — 0Total — 3 (13.6%)

LMCA, left main coronary artery; PTCA, percutaneous transluminalcoronary angioplasty; IABP, intra-aortic balloon pump; RCA, right coro-nary artery; MI, myocardial infarction; CABG, coronary artery bypass graftsurgery.

Left Main Intervention 25

early deaths in either group, and the total mortality ratefor the protected group was 14.3% compared with 25%for the unprotected group (P5 NS). The incidence of lateintervention with repeat PTCA or CABG was 50% in theprotected group compared with 25% in the unprotectedgroup (P5 NS).

IABP Supported Versus Unsupported LMCA PTCA(Table VII)

Twenty of 28 patients (71.4%) underwent LMCAPTCA with no IABP support. Only 1 patient (5%) washaemodynamically unstable in this group, but no IABPwas used in this patient because emergent LMCA PTCAwas performed in the setting of refractory ventriculararrhythmias with cardiogenic shock after diagnostic car-diac catheterization demonstrating severe LMCAdisease.Despite successful LMCA dilatation, the patient died dueto refractory ventricular arrhythmias and pump failure.Five of 8 patients (62.5%) in whom IABP support wasused had cardiogenic shock. All patients in the unsup-ported group had a protected circulation compared withnone in the supported group. The early mortality rate was5% in the unsupported group compared with 50% in thesupported group (P 5 0.09). The total mortality rate was20% in the unsupported group compared with 62.5% inthe supported group (P5NS). On final follow-up, 8 of 20

patients (40%) in the unsupported group were free ofmajor cardiac events compared with only 1 patient(12.5%) in the supported group (P5 NS).

Procedural and Clinical Featuresof LMCA PTCA Deaths

Table VIII shows the clinical features and the timing ofdeath of these patients. Only 2 of the deaths were inpatients with a protected left coronary circulation; in bothcases, death occurred late. An early death was associatedwith the presence of cardiogenic shock/acute myocardialinfarction in all cases.

DISCUSSION

The data reported above suggest that angioplasty of theLMCA, although an attractive idea, carries a significantrisk and that interventions for LMCA disease must focuson distinct patient groups.Acute occlusion of the LMCA is a rare angiographic

finding, and most of the patients in this clinical setting dieof sudden death or cardiogenic shock [23–25]. Emer-gency angioplasty of the LMCA as the culprit lesion inthe setting of an acute myocardial infarction and/orcardiogenic shock is associated with a poor outcome, anda hospital mortality rate as high as 50% or greater can be

TABLE VI. Clinical Outcome in Elective Protected VersusElective Unprotected LMCA PTCA

ElectiveProtected

ElectiveUnprotected

Number of patients 14 8Follow-up (months) 19.86 13.5

(range 4.5–45)136 8.4(range 2–30)

Stent 7 (50%) 8 (100%)Clinical follow-upDeathPredischarge 0 0Late 2 2Total 2 (14.3%) 2 (25%)

MIPredischarge 0 1Late 0 0Total 0 1 (12.5%)

Repeat PTCAPredischarge 0 0Late 4 (28.6%) 2Total 4 (28.6%) 2 (25%)

CABGPredischarge 0 0Late 0 0Total 3 (21.4%) 0

Repeat CABG/PTCA 7 (50%) 2 (25%)

LMCA, left main coronary artery; PTCA, percutaneous transluminalcoronary angioplasty; MI, myocardial infarction; CABG, coronary arterybypass graft surgery.

TABLE VII. Clinical Outcome in IABP Supported VersusUnsupported LMCA PTCA

UnsupportedIABP

Supported

Number of patients 20 8Protected 14 (70%) 0Stent 11 (55%) 6 (75%)Cardiogenic Shock 1 (5%) 5 (62.5%)Clinical outcomeDeathProcedural 1 (5%) 2Procedure to discharge 0 2Late 3 (15%) 1Total 4 (20%) 5 (62.5%)

MIPredischarge 0 1 (12.5%)Late 0 0Total 0 0

Repeat PTCAPredischarge 0 0Late 5 (25%) 1 (12.5%)Total 5 (25%) 1 (12.5%)

CABGPredischarge 0 0Late 3 (15%) 0Total 3 (15%) 0

IABP, intra-aortic balloon pump; LMCA, left main coronary artery; PTCA,percutaneous transluminal coronary angioplasty; MI, myocardial infarc-tion; CABG, coronary artery bypass graft surgery.

26 Chauhan et al.

expected [14]. This is confirmed in our study in which thein-hospital mortality rate was 83.3% (5 of 6 patients) inthe subgroup of patients undergoing acute LMCAPTCA.It is not possible to identify these patients with criticalLMCA disease in the acute setting until they are in thecatheterization laboratory undergoing angiography. Thetemptation to intervene is enormous, because most ofthese patients are moribund and unlikely to survivewithout prompt reestablishment of LMCApatency. Emer-gency CABG should be considered in these patients, andLMCA angioplasty can be performed if surgery is notpossible with the expectation of a high procedural andin-hospital mortality rate. The use of IABP support in thepresence of acutemyocardial infarction/cardiogenic shockwas associated with a high procedural and in-hospitalmortality. However, the numbers are small, and the datashould be interpreted with caution because these high-risk patients would be expected to have a high mortalityrate due to their comorbid factors.Elective LMCAPTCA has more favorable results. The

total mortality rate in the elective group was 18.2%revascularization with PTCA or late elective CABGoccurring in 41%. The largest experience of PTCA of theLMCA are the 127 patients reported by O’Keefe et al.[14]. Table IX compares the results of our study with theirstudy. The results of all elective LMCA PTCA in ourstudy are very similar to the larger experience reported byO’Keefe et al. [14], although the number of patients inour study is small. The total mortality rate in our study ishigher (18.2% versus 4.3%), although there were noprocedural deaths in this group in our study. Thisdifference may be due to a smaller patient population anddifferences in patient comorbidity for adverse outcomes.More than 90% of patients in our elective LMCA PTCAgroup were in the hospital with unstable angina. All

patients were considered inoperable for CABG in ourstudy compared with only 27% in O’Keefe et al.’s study.The late follow-up data in the elective group show asimilar late mortality, repeat PTCA, and late CABG ratesin patients surviving initial hospitalization. Unlike theirstudy, however, elective PTCA in unprotected patients inour study was not associated with a high proceduralmortality and poor long-term prognosis compared withelective protected LMCA PTCA. This is similar to the

TABLE IX. Comparison of Procedural and Clinical OutcomeWith O’Keefe et al. [14]

O’Keefeet al.

CurrentStudy

Late follow-up, all hospital dischargesNumber 98 23Nonfatal MI 7% 0CABG 15% 13.4%Late mortality 21.4% 17.4%Overall mortality 28% 32.1%

Outcome in all elective LMCAPTCANumber 117 22Procedural mortality in unprotectedpatients 9.1% 0

Procedural mortality in protected patients 2.4% 0Urgent CABG 1.7% 0Total mortality 4.3% 18.2%*

Late follow-up, elective LMCAPTCANumber 93 22Late MI 6.5% 0PTCA 28% 27.3%CABG 14% 13.6%Combined PTCA/CABG 41.9% 40.9%Late mortality 25.8% 18.2%

*P5 0.08.MI, myocardial infarction; CABG, coronary artery bypass graft surgery;LMCA, left main coronary artery; PTCA, percutaneous transluminalcoronary angioplasty.

TABLE VIII. Procedural and Clinical Features of LMCA PTCADeaths

Protected StentAge.70 IABP Shock/MI Procedural Predischargea

30daysb Latec

Patient 1 1 2 2 2 2 2 2 2 1 (19 months)Patient 2 2 1 2 1 2 2 2 2 1 (2 months)Patient 3 2 1 2 1 1 2 1 2 2

Patient 4 2 1 1 1 1 2 1 2 2

Patient 5 1 1 2 2 2 2 2 2 1 (4.5 months)Patient 6 2 2 1 1 1 1 2 2 2

Patient 7 2 2 1 1 1 1 2 2 2

Patient 8 2 1 2 2 2 2 2 2 1 (4 months)Patient 9 2 2 2 2 1 1 2 2 2

MI, Myocardial infarction; IABP, intraaortic balloon pump.aAfter leaving the cardiac catheterization laboratory but before discharge.bHospital discharge to 30 days.c30 days to final follow-up.LMCA, left main coronary artery; PTCA, percutaneous transluminal coronary angioplasty; IABP, intra-aortic balloon pump; MI, myocardial infarction;1,positive event;2, no event.

Left Main Intervention 27

experience reported by Tommaso et al. [18], who reportedno difference in outcome between the protected andunprotected LMCA PTCAs in 42 patients. Our experi-ence with elective LMCA PTCA in patients presentingpredominantly with unstable angina requiring hospitaliza-tion and in whom CABG had been declined suggests thatfavourable results may be obtained in these patients inboth protected and unprotected groups. Furthermore, asuccessful LMCA intervention in these patients at a timewhen CABG is not possible allows the possibility offuture CABG. In more than 10% of our patients in theelective group, bypass surgery was successfully under-taken at a later date for recurrence of symptoms. Thesepatients now being considered as at acceptable risk withan improvement in their comorbid conditions.The availability of stents and their success in reducing

acute complications and restenosis may suggest a role forthem in LMCA PTCA. Left main disease is oftencharacterized by aorto-ostial involvement and bulky,eccentric stenoses, lesion characteristics that may imposelimitations on balloon angioplasty. Stenting may beappropriate to prevent the significant recoil seen afterballoon angioplasty of aorto-ostial LMCA disease due toorientation of elastic fibers in the aorta, to treat or preventdissections in the body of left main after balloon angio-plasty, or to treat left main bifurcation disease. A smallnumber of LMCAstents has been reported previously, butthe stenting of unprotected left mains has been rarelyreported [23–25]. Stents were used for suboptimal PTCAresult or for threatened closure in 4 of 17 stent cases(24%) in our study. The hospital mortality rate, latemortality, and late revascularization with repeat PTCA orCABG were similar in patients treated with stents andthose treated with conventional balloon angioplasty. Theuse of stents in our study was more likely in patients withunprotected circulation (59% with unprotected versus36% with protected left circulation). It may also be thatthe greater use of stents in the elective unprotected group(100% versus 50% in the elective protected group)improved their procedural and late clinical outcome,making it comparable to LMCA intervention in theprotected group. However, the numbers in the varioussubgroups are small. Because we obtained angiographicfollow-up in only those patients who returned withsignificant symptoms, we cannot assess the actual resteno-sis rate in this study. Angiographic follow-up was avail-able in only 10 patients, and 5 (50%) had a significantLMCA restenosis requiring repeat PTCA. This highincidence of restenosis is consistent with previous reports[14,26,27]. There is little experience with LMCA stent-ing, and further experience and refinement of stent designmay allow broader application in LMCA intervention.We did not perform IVUS in any of our patients. It is

often difficult to assess the actual size of the LMCA on

angiography. The use of IVUSmay be helpful in selectingappropriate size balloons and or stents. The amount andextent of calcification may also be assessed more accu-rately with IVUS, which can afford improved guidance inachieving optimal stent expansion or may help in select-ing other modalities of therapy, such as the use ofrotational atherectomy in patients with significant calcifi-cation. However, the use of IVUS may be restricted toselected elective cases due to the acuity of clinicalpresentation of a significant number of patients withLMCAdisease.An important observation from our study is the poor

outcome of patients with unprotected LMCAdisease whopresent with acute myocardial infarction and cardiogenicshock. The high mortality rate amplifies the inability ofthe IABP to support the circulation in these conditions,despite the procedure being undertaken in all patients inour study within 12 hr of the onset of the myocardialinfarction syndrome. Percutaneous cardiopulmonary sup-port (CPS) was not used in any patient because thistechnique is not used frequently in our institution. Theinitiation of CPS is a relatively complex procedurerequiring specific technical skills and a high degree ofcoordination among the staff in the catheterization labora-tory. To be able to initiate CPS urgently, it is mandatorythat the team is well practiced in the technique. Further-more, the high mortality reported in these patients isprobably not the function of the support device used, butrather a function of the high risk of the patients undergo-ing the procedure.

CONCLUSION

Our study suggests that angioplasty of the LMCA,although an attractive idea, carries a significant risk andthat interventions for LMCA disease must focus ondistinct patient groups. Although coronary artery bypasssurgery is the treatment of choice for patients with LMCAdisease, elective PTCA and/or stenting may be under-taken with high procedural success rates when patientshave prohibitive surgical risks. However, our data do notsupport intervention in the presence of acute myocardialinfarction/cardiogenic shock. Intervention in acute LMCAocclusion carries a high procedural mortality and poorlong-term outcome despite the use of stents and IABPsupport.

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