percutaneous transluminal coronary angioplasty in african-american patients (the national heart,...

CORONARY ARTERY DISEASE

I ( The

American Journal

of Zardiology

Although black patients have a higher prevalence of risk factors for coronary artery disease, the outcome of coronary angioplasty in black pa Gents is not known. The purpose of this study was to determine if any racial differences ex. isted in the clinical characteristics and outcome of patients enrolled in the 19664986 National Heart, Lung, and Blood Institute (NHLBI) Percuta neous Transluminal Coronary Angioplasty (PTCA) Regmtry. The clinical characteristics, ht-hospital event rates, and Syear followup results of all patients enrolled in the 19664966 NHLBI PTCA Registry were examined with respect to race. Of the patients enrolled in the registry, 1,999 (90.6%) were white and 76 (3.6%) were black. Among btack patients there were more women (50% vs 24%, p <O.OOl), and more patients who had hypertension (73% vs 45%, p eO.001) and diabetes (23% vs 13%, p <0.05). Black patients were more likely to have multivessel disease (72% vs 46%, p ~0.001). Clinical success rates were similar (76.3% for blacks and 79.3% for whites), but because black patients had more vessels with significant disease, complete revae cularization was achieved in 26% of black patients compared with 44% of white patients

From the Andreas R. Gruentzig Cardiovascular Center, Division of Car- diology, Emory University Hospital, Atlanta, Georgia; the PICA Reg- istry, Data Coordinating Center, Department of Epidemiology, Grddu-

ate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania; and the Division of Cardiology, Medical College of Vir- ginia, Richmond, Virginia. This project was supported in part by Grants HL-33292 and HL49743.02 from the National lnstitutes of Health. Dr. Scott is a fellow of the Robert Wood Johnson Foundation for Minority Faculty Development. Manuscript received June 10. 1993; revised manuscript received November 4. 1993. and accepted November 6.

Address for reprints: Neal A. Scott, MD, PhD, Andreas R. Gruentzig Cardiovascular Center, Emory University Hospital, F-606, 1364 Clifton Road, Atlanta, Georgia 30322.

JUNE 15, 1994, VOL. 73, NO. 16

Percutaneous Transluminal Coronary Angioplasty in African=American Patients

(The National Heart, Lung, and Blood Institute 1985-1986 Percutaneous Transluminal

Coronary Angioplasty Registry) Neal A. Scott, MD, PhD, Sheryl F. Kelsey, PhD, Katherine Detre, MD, Dr PH,

Michael Cowley, MD, Spencer B. King III, MD, and the NHLBI PTCA Registry Investigators

(p <O.OOl). After the P’fCA procedure there was no significant difference in mq@r complications (death, myocardial infarction, or emergent core nary artery bypass grafting) between the 2 groups. Rveyear followup data revealed that there was no significant difference in mortality, myocardial infarction, -w afiery bypass grafting, or repeat PTCA. Black patients in the NHLBI P7CA Registry had a similar imidence of acute and long-term events when compared with white patients despite the presence of more car diovascular risk factors, symptoms, and multivessel disease.

(Am J Cardiol l-73:1141-1146)

C ardiovascular disease is the major cause of morbidity and mortality in the United States.’ Coro- nary artery disease is the most common cause of

death among cardiovascular causes.’ Data from multiple sources indicate that the death rate for black Amer- icans is higher than for the general population, in part because of the higher mortality from cardiovascular causes.2 According to mortality data of the National Cen- ter for Health Statistics, coronary artery disease is the leading cause of death among black Americans3 Dur- ing the period 1979 to 1985, the mortality related to coronary disease was higher among black than white patients.4 The development of coronary revascularization procedures such as percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft surgery has provided for significant relief of symp- toms5-8 and, in selected cases, an increase in survival.’ When managed with coronary artery bypass graft surgery, black patients appear to have a long-term survival similar to that seen in white patients.‘e This study was performed to assess the outcome of black patients treated with PTCA.

PTCAINBLACKS 1141

r Odds Ratio

Blacks Versus Black White Whites

(n = 76) (n = 1,939) Characteristics % % OR (95% Cl)

Age 2 65 years*$ 19.7 26.7 0.68 (0.30, 0.98) Woment 50.0 24.3 3.11 (1.90,4.93) Unstable anginat 75.0 53.0 2.66 (1.57, 4.50) Angina class 3 or 49 72.2 52.0 2.49 (0.94, 6.60) Prior bypass coronary 10.5 11.8 0.88 (0.42, 1.85)

surgery Prior myocardial 44.6 38.0 1.32 (0.86, 2.11)

infarction+ Heart failure 5.3 5.0 1.07 (0.38, 2.98)

(history)* Diabetes mellitus 23.0 12.7 2.06 (1.18, 3.60)

(history)*$ Hypertension (history)tS 73.0 44.5 3.36 (2.00, 5.66) Hypercholesterolemia$ 37.7 34.5 1.15 (0.68, 1.95) Family history of 45.6 48.0 0.91 (0.56, 1.48)

coronary disease$ Current smoker? 45.3 27.9 2.14 (1.34, 3.41) Ejection fraction i 50%$ 14.9 18.1 0.79 (0.40, 1.58)

*p <0.05; tp <O.OOl~ ~n&~a~tients were m~ssmg data. Percentages were computed using patients with

§Only given for patients with stable angIna. Cl = confidence interval; OR = odds ratio.

I

METHODS

TABLE I Clinical Characteristics

To monitor the safety and efficacy of PTCA, the Na- tional Heart, Lung, and Blood Institute (NHLBI) PTCA Regisq was initiated to provide information on the use and safety of FTCA in a consecutive group of patients treated’ at 16 clinical centers with considerable experience with the technique.U The data obtained from these patients have been used to assess success, complications, and mortality associated with PTCA.6,12-15

The NHLBI 1985-1986 PTCA Registry enrolled consecutive patients who underwent their fist PTCA by one of the study investigators between August 1985 and May 1986. A total of 2,431 patients were entered into the registry. Two hundred ninety-five patients whose PTCA was performed within 10 days of a myocardial infarction were excluded from the analysis. Of this group without an acute myocardial infarction (classified as white, black, or other), all patients of unknown or “other” races (120) were excluded. The clinical variables and in-hospital

event rates were examined in the remaining 2,015 patients with regard to race. Five-year follow-up information was obtained from 1,793 (89.0%) patients who were alive and contacted in 1991. This represents a 98.5% rate of follow-up among patients who were alive.

Vessel disease was classified as single, double, or triple, according to the definitions of the Coronary Artery Surgery Study. I6 Successful dilatation of a lesion was detied as a reduction by 220% of the narrowing of the vessel diameter. Clinical success was defined as successful dilatation of all lesions in which angioplasty was attempted, without in-hospital death, myocardial infarction, or coronary artery bypass graft surgery. Angina was classified according to the guidelines of the Canadian Cardiovascular Society. l7

Statistical analysis: For comparison of the 2 race groups, chi-square tests were used for categorical data and Student’s t test was used to examine the differences in continuous variables. Logistic regression models were fitted to estimate the odds ratios of risk factors for blacks compared with whites, for blacks compared with whites adjusted for gender, and for blacks compared with whites adjusted for clinical site and gender. Cox regression analysis was performed with 5-year mortality as the outcome variable. The independent variables incorporated into the multiple logistic regression model were race (black/ white), sex, age, cigarette smoking, diabetes, hypertension, unstable angina, registry site, prior myocardial infarction, prior coronary artery bypass graft surgery, vessel disease, ejection fraction <50%, inoperable/high risk surgical candidate, and history of congestive heart failure.

RESULTS Over half (56%) of the black patients entered into the

NHLBI PTCA Registry were treated at 1 of the 16 clinical centers. Eight other centers contributed between 1 and 10 black patients to the NHLBI registry. Seven centers did not contribute any patients. Baseline clinical and angiographic characteristics are summarized in Table I. There was a significant gender difference between the 2 groups. Seventy-five percent of white patients were men; however, there was an equal distribution of black men and women who underwent angioplasty. Unstable angina was more frequently a complaint of black patients.

TABLE II Baseline Comparison of Male and Female Patients

Men Women

Black White Black White (n = 38) (n = 1,467) (n = 38) (n = 472)

Race - ___ Race Gender Characteristics No. (%) No. (%I Diff.11 No. (%) No. (%) Diff.11 Diff.ll

Age 2 65 years 9 (24) 324 (21) 6 (16) 204 (43) t $ Mean (years) age 55.3 56.5 56.6 61.3 t $ Unstable angina 24 (63) 738 (50) 33 (87) 290 (61) t $

History of diabetes mellitusg 5 (13) 158 (11) 12 (33) 85 (18) * $

History of hypertensiong 15 (68) 594 (41) $ 29 (78) 262 (56) t f Current smoking 19 (51) 392 (28) t 15 (39) 131 (28)

1142 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 73 JUNE 15, 1994

Of those patients presenting with unstable angina, the majority had angina with minimal exertion or at rest. Blacks were twice as likely to have a history of diabetes, 3 times as likely to have hypertension, and twice as likely to be cigarette smokers. There was no significant difference in the presence of hypercholesterolemia, history of congestive heart failure, history of myocardial infarction, or family history of coronary artery disease. The percentage of patients who were designated inoperable or high-risk surgical candidates was also similar between both groups.

Table II examines the racial differences in selected characteristics separately for the 1,505 male patients and for the 510 female patients. Compared with whites, black men were more hypertensive and more likely to be cigarette smokers. Black women had a history of diabetes and hypertension more frequently than white women. Black women were younger and were more likely to have unstable angina.

Because most of the black patients came from 1 site (Medical College of Virginia), a comparison of the Med- ical College of Virginia with all other sites was performed (Table III). Compared with other sites, the Med- ical College of Virginia entered more women, more patients with unstable angina, diabetes, current smoking, and multivessel disease. Rates of hypertension were similar in the Medical College of Virginia and other sites. All the factors listed in Table III were more prevalent in blacks than in whites at the Medical College of Virginia as well as at other clinical sites. However, not all of the differences were statistically significant.

Table IV lists the odds ratios of the prevalence of risk factors for blacks compared with whites adjusted fust for gender and second for gender and clinical site. Blacks were less likely to be aged >65 years, and this relation holds even when gender and clinical site differences were taken into account. Blacks were 2.38 times more likely to have unstable angina, as reflected by the odds ratio

TABLE III Baseline Comparison of Medical College of Virginia with All Other Sites (by race)

Medical College of Virginia All Other Sates

Black White Black Whrte (n = 43) (rl = 211) (n = 33) (n = 1,728)

Race __ Race Gender No. (%) No. (%) D~ff.ll No. (%) No. (%I Diff .I1 Diff.1

Female gender 25 (58) 71 (34) t 13 (39) 401 (23) * t Unstable angina 38 (88) 163 (77) 19 (58) 865 (50) t History of diabetes 10 (24) 33 (16) 7 (22) 210 (12) *

mellitus§ History of hypertensions 35 (81) 76 (36) t 19 (61) 780 (46) Current smokersg 25 (58) 88 (42) 9 (28) 435 (26) i Multivessel disease 36 (84) 144 (68) * 19 (58) 792 (46) $

l p <0.05; tp <O.OJ; tp <O.OOl. /,Some patrents mlssmgdata. Slgnlflcance of the difference between blacks and whites. Slgnlfvzance of the difference between Medical College of Vlrgwla and all other sites, collapsmg over race.

TABLE IV Clinical Characteristics

Characteristics

Odds Ratlo-Blacks Versus Whrtes

Adjusted for Gender

OR (95% Cl)

Odds Ratio-Blacks Versus Whites Adjusted

for Gender & Site+

OR (95% Cl)

Age z 65 years* &stable angina Canadian heart

class 3 or 4f Prior bypass surgery Prior myocardial

infarction* History of congestive

heart failure* History of drabetes

mellitus* Hrstory of hypertension* Cholesterol*

Family history of coronary artery disease*

Current smoker Ejection fraction i 50%

0.51 (0.28, 0.91) 0.54 (0.30. 0.99) 2.38 (1.40, 4.04) 1.50 (0.85, 2.62) 2.44 (0.92. 6.50) 2.52 (0.94, 6.77)

0.93 (0.43, 1.96) 1.46 (0.91, 2.34)

0.91 (0.42, 1.96) 1.55 (0.95, 2.53)

0.85

1.77 (1.00,3.11) 1.62

2.95 (1.74, 4.99) 3.50 1.04 (0.61, 1.77) 1.06 0.87 (0.53. 1.42) 0.87

2.14 (1.34, 3.42) 1.52 0.94 (0.47, 1.89) 1.18

(0.30, 2.39) 1.05 (0.35, 3.08)

(0.89, 2.94)

(2.03, 6.05) (0.61, 1.84) (0.52, 1.45)

(0.93, 2.87) (0.57, 2.43)

*Some patients were missmg data. Percentages were computed usmg patients with known data. tOnly given for patlents with stable angina. $Medical College of Virginia versus other cl~nlcal sites. Abbreviations as in Table I.

PTCAIN BLACKS 1143

TABLE V Angiographic Characteristics

Patient Variables

Black White 01 = 76) (n = 1,939)

Odds Ratic+-Blacks No. (%) No. (%) Versus Whites 95% Cl

Vessel disease* Single 21 (28) 964 (50) 2.5911 Double 31 (41) 583 (30) Triple 24 (32) 353 (18) Left main 0 (0) 39 (2)

Number of lesions attempted9

Single 43 (57) 1,219 (63) 1.31n Multiple 33 (44) 716 (37)

Number of vessels attempted5 1 58 (76) 1,555 (80) 1.27** 2 15 (20) 332 (17) 3 3 (4) 48 (3)

Lesion Variables n = 131 n = 2,989

Calciumtt 15 (11) 328 (11) Thrombustt 14 (11) 182 (7) Receives collateralstt 32 (25) 509 (20) Supplies collateralstt 12 (10) 230 (9) Geometry of target lesiontt

Eccentric 51 (41) 1,383 (48) Concentric 74 (59) 1,514 (52)

lntimal teartt 46 (35) 844 (28) Stenosis before PTCA (mean)t 85.4 81.5 Stenosis after PTCA (mean)* 38.7 33.8

*p <0.05; tp <O.Ol; tp < 0.001. §Four patients had no vessels or lesions attempted.

1 ‘. Mulbple versus single-vessel disease. Mulbple versus single-lesion attempts.

**Multiple versus single-vessel attempts. tWome patients were missing data. Percentages were computed using patients with known data. PTCA = percutaneous transluminal coronary angioplasty; other abbreviations as in Table I.

(1.55,4.31)

(0.83,2.08)

(0.74,2.19)

adjusted for gender. However, when clinical site was taken into account, the estimate of the odds ratio was re- duced to 1.50. This was not statistically significant at the 0.05 level. Cigarette smoking, like unstable angina, was significantly more prevalent among blacks with an odds ratio adjusted for gender of 2.14. When clinical site was considered, the odds ratio for smoking was not statistically significant. Differences in other factors including prior coronary artery bypass graft surgery, prior myocardial infarction, history of diabetes, and history of hypertension were not altered when clinical site was considered.

Angiographic data are listed in Table \! Although there was a higher incidence of multivessel disease in black patients, there was no significant difference in the number of lesions attempted or the number of vessels that were treated with PTCA. When the characteristics of the attempted lesion sites were examined, there was no difference between groups in the location of the lesion (left main coronary artery, left anterior descending, left circumflex, right coronary), morphology (single discrete, multiple discrete, diffuse, tubular), geometry (concentric, eccentric), or the presence of calcium. The presence of thrombus at the FTCA site and collateral flow toward the target lesion were more frequently seen in black patients. The percent stenosis before and after the procedure did not differ between groups. Table VI de-

scribes the procedural outcome. The proportion of com- pletely successful procedures was similar in both groups. The rates of target coronary artery occlusion were similar, as were the incidences of coronary dissection and coronary spasm. There was no difference in the presence of intimal tears after the procedure. Coronary branch occlusion was a catheterization laboratory complication that was seen more frequently in black patients. There was also no difference in complications related to the PTCA procedure that occurred outside of the catheterization laboratory. Major outcome variables are described in Table VII. Residual coronary artery disease after the PTCA procedure was more extensive in black patients, but this is explained by the fact that they had more extensive disease initially. There was no significant difference in the clinical success rate. In addition, rates of myocardial infarction, death, and emergent and elective coronary artery bypass graft surgery were similar in the 2 racial groups. Although the duration of hospitalization was significantly longer in the black patient group, this difference could be explained by length of hospitalization at the Medical College of Virginia. The median number of days in the hospital was 2 for whites and 3 for blacks, whereas at all other sites, the median hospital stay was 2 days for both whites and blacks.

When the 5-year outcome was examined (Table VIII), there was no difference in the incidence of death,

Id.44 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 73 JUNE 15,1994

TABLE VI Procedural Complications

Results

In catheterization laboratory

No event Coronary spasm Coronary occlusion Coronary branch occlusion* Coronary dissection Ventricular fibrillation

Out of catheterrzahon laboratory

No event Prolonged angina Abrupt closure Major entry site complication

*p co.05.

Black (n = 76)

No. (%)

63 (83) l(1) 3 (4) 4 (5) 5 (7) 0 (0)

63 (83) 6 (8) 2 (3) 5 (7)

White (n = 1,939)

No. (%)

1,667 (86) 19 (1) 94 (5) 34 (2)

100 (5) 24 (1)

1,708 (88) 115 (6)

56 (3) 54 (3)

TABLE VII Outcome of Initial Procedure

Black (n = 76)

White (n = 1,939)

Results No. (%)

Residual vessel disease* None 20 (26) Single 26 (34) Double 14 (18) Triple 16 (21) Left main 0 (0)

Myocardial infarction 5 (7) Death 0 (0) Emergency bypass surgery 3 (4) Elective bypass surgery 2 (3) Cknical success 58 (76)

‘p <O.OOl for none compared with other variables

No. (%)

853 (44) 614 (32) 308 (16) 133 (7)

31 (2) 88 (5) 16 (1) 70 (4) 40 (2)

1,537 (79)

myocardial infarction, coronary artery bypass grafting, or repeat PTCA between the black and white patient groups. A multivariate Cox regression analysis was performed to identify the risk factors that correlate with a better 5year survival. Black patients had a slightly better survival relative to whites after controlling for their more severe risk factors, but race was not a significant independent predictor of outcome.

Although the difference was not statistically significant, at 5-year follow-up, relatively fewer black than white patients reported no angina (66% vs 81%). How- ever, when improvement was defined as no angina or angina less severe than before initial FICA, rates of improvement among black and white patients were nearly the same (89% vs 91%).

At the 5-year telephone interview, patients were asked about employment status. Significantly more blacks than whites reported retirement due to a noncar- disc medical problem (13.1% vs 4.0%; p <O.Ol), but this was true at baseline before initial PTCA (9.2% vs 2.4%; p ~0.01). In addition, black patients were somewhat more likely to report retirement due to cardiac disease at 5 years (13.1% vs 8.3%) and before FTCA (9.2% vs 6.1%).

DISCUSSION The NHLBI PICA Registry was initiated to provide

baseline and follow-up information on patients under- going coronary angioplasty. The overall goal of the registry was to evaluate the safety and efficacy of PTCA and to provide the necessary information for the design of controlled trials to compare this clinical efficacy with other methods of treatment for ischemic heart disease (e.g., medical treatment and coronary artery bypass surgery). The results from this registry are frequently used to compare the results of alternative therapies, and to inform patients of what risks and benefits they can ex- pect from the procedure.

Because all consecutive FTCA cases were entered into the registry between August 1985 and May 1986, the proportion of black patients in the registry is assumed to reflect the true proportion of black patients who un-

TABLE VIII Five-Year Outcome

Black White fn = 76) In = 1,939)

Death Myocardial infarction Bypass surgery Repeat PTCA

Angina status* of survrvorst None Present but less severe than before PTCA

Present same or worse than before PTCA

Total

No. (%I No. (%)

8 (11) 187 (10) 10 113) 265 (14) 15 (20) 376 (19) 19 (25) 537 (28)

43 (66) 1,382 181) 15 (23) 188 (12)

7 (11) 128 (8)

65 1,698

*Angina status unknown for 30 surviving patients. tAlive and contacted in 1990.

I I

derwent PTCA at these sites during the enrollment period. Because over half of the black patients enrolled in the registry came from 1 center, the proportion of black patients who underwent PTCA at the other sites was far less than expected, given the proportion of black patients in the metropolitan areas where the clinical centers were located. These findings can best be explained by the pos- sible presence of bias in the referral of patients to these centers. However, data exist to suggest that black patients do not undergo invasive cardiac procedures or coronary artery bypass operations as frequently as white patients. A recent statewide population-based analysis examined all admissions for coronary-related disease and found that although admission rates for whites and blacks were similar, white patients underwent twice as many angioplasty and coronary artery bypass grafting procedures than black patients. These interracial inequalities were not merely a function of diminished physician contact and lower disease recognition for the black patients because the differences were evident even among the cohort of patients hospitalized for serious cardiovascular conditions.18 Ford et all9 examined the av-

PTCA IN BLACKS 1145

erage rates for coronary arteriography, coronary artery bypass graft surgery, and acute myocardial infarction in the United States for the period 1979 to 1984. They compared the rate of acute myocardial infarction to arteriography and coronary artery bypass graft surgery and found that black men, when compared with white men, were only half as likely to undergo arteriography and one third as likely to undergo coronary artery bypass graft surgery despite an acute myocardial infarction rate that was 77% that of white men. Similar differences, although not as marked, were also present for black and white women.i9 Another study examined coronary artery bypass graft surgery procedures funded by Medicare na- tionwide. There was a large disparity in the number of procedures performed between racial groups. Nationally, the coronary artery bypass graft surgery rate was 27.1/10,000 for whites and 7.6/10,000 for blacks. In the southeastern United States, whites were 7 times more likely to undergo a coronary artery bypass graft surgery procedure than blacks.*O

The relatively small number of black patients enrolled in the NHLBI FTCA Registry may not be repre- sentative of all black patients with coronary artery disease. However, the data suggest that in these 2 selected populations, there were significant differences in baseline characteristics by race. Black patients had a higher female predominance, and a higher incidence of diabetes and hypertension. In addition, black patients had more multivessel disease. Because most of the black patients came from the Medical College of Virginia, a comparison of this site with all other sites was performed to examine more closely the risk profiles of black patients. Blacks had more unstable angina, multivessel disease, and were more likely to smoke at the Medical College of Virginia as well as at all other sites. However, these trends were magnified because a large percentage of the black patients came from the Medical College of Vir- ginia, where all patients (white and black) were more likely to have these risk factors. Therefore, a site effect did exist and the race effects were somewhat confounded with it. Although these observations did not invalidate any of the prior analyses, they did indicate that some of the race effects on risk factors may not be as large as they appeared to be since they can partly be explained as site effects.

Although black patients in this study had more hypertension, diabetes, and multivessel disease, there was no difference in acute complications except for coronary branch occlusion. Because clinical success rates were similar, the increased hospital stay in the black population was probably due to the presence of co-morbid diseases. The 5year outcome was not different between the 2 groups despite the presence of more residual vessel disease in black patients. In addition, angina after the procedure was not significantly different between the 2 groups. Of those with angina, black patients demon- strated a trend toward less severe discomfort compared with their baseline presentation. There was no significant change in employment status after the procedure. Black patients were more likely to be medically retired due to noncardiac causes. This probably is a reflection of the higher incidence of other medical diseases.

In summary, data from the NHLBI 1985-1986 FTCA Registry shows that blacks, despite more co-morbidity and more coronary risk factors, undergo successful coronary angioplasty procedures and have excellent long- term outcome as often as whites. These results must be tempered by the relatively small number of black patients enrolled in the registry and the comparatively large number that were recruited from 1 site. However, given the good results of PICA in blacks enrolled in this registry, reluctance to perform FTCA in this patient group may be unfounded.

1. Vital statistics of the United States, Hyattsville, MD:U.S. Dept. of Health and Human Services, 1991: 10. 2. Haywood LJ. Issues in the natural history and treatment of coronary heart disease in black populations: medical management. Am Hear? J 1984;108:683-687. 3. Gillum RF, Liu KC. Coronary heart disease mortality in United States blacks, 194&1978: trends and unanswered questions. Am Hear? J 1984;108:728-732. 4. Sempos C, Cooper R, Kovar MG, McMillen M. Divergence of the recent trends in coronary mortality for the four major race-sex groups in the United States. Am J Public Health 1988;78:1422-1427. S. Gruentzig AR, King SB III, Schlumpf M, Siegenthaler W. Long-term follow-up after percutaneous transluminal coronary angioplasty: the early Zurich experience. NE&J Med 1987;316:1127-1132. 6. Kent KM, Bentivoglio LG, Block PC, Bourassa MG, Cowley MJ, Dorms G, D&e KM, Gosselin AI, Gruentzig AR, Kelsey SF, Mock MB, Mullin SM. Pa.- samani ER, Myler RK, Simpson I, Stertzer SH, Van Raden MJ, Williams DO. Long-term efficacy of percutaneous transluminal coronary angioplasty (PICA): report from the National Heart, Lung, and Blood Institute flCA Registry. Am J Car- dial 1984;53:27C-31C. 7. CASS Principal Investigators. Coronary Artery Surgery Study (CASS): a randomized trial of coronary artery bypass surgery. Quality of life in patients randomly assigned to treatment groups. Circulation 1983;68:95 l-960. 8. Hultgren H, Peduzzi P, De&e K, Takaro T. The 5 year effect of bypass surgery on relief of angina and exercise performance. Circularion 1985;72(suppl V):V- 79-V-83. S. European Cooperative Surgery Study Group. Long-term results of prospective randomized study of coronary artery bypass surgery in stable angina pectoris. Lancet 1982;2:1173-1180. 10. Maynard C, Fisher LD, Passamani ER. Survival of black persons compared with white persons in the coronary artery surgery study (CASS). Am J Cardiol 1987;60:513-518. Il. Mullin SM. Passamani ER, Mock M. Historical background of the National Heart, Lung, and Blood Institute Registry for percutaneous transluminal coronary angioplasty. Am J Cardiol 1984;53:3(34C. 12. Detre KM, Holubkov R, Kelsey S, Bourassa M, Williams D, Holmes D, Dar- ros G, Faxon D, Myler R, Kent K, Cowley M, Cannon R, Robertson T. One-year follow-up of the 1985-1986 National Heart, Lung, and Blood Institute’s Percuta- neous Transluminal Angioplasty Regisy. Circularion 1989;80:421428. 13. Detre KM, Holmes DR, Holubkov R, Cowley MJ, Bourassa MG, Faxon DP, Dorms GR, Bentivoglio LG, Kent KM, Myler RK. Incidence and consequences of periprocedural occlusion. Circulation 1990;82:73’+750. 14. Holmes DR, Holubkov R, Vlietstra RE, Kelsey SF, Reeder GS, Dorros G, Williams DO, Cowley MJ, Faxon DP, Kent KM, Bentivoglio LG, Detre KM. Com- parison of complications during percutaneous transluminal coronary angioplasty from 1977 to 1981 and from 1985 to 1986: The National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty Registry. JAm Co0 Car- dial 1988;12:1149-1155. l6. Detre K, Holubkov R, Kelsey S, Cowley M, Kent K, Williams D, Myler R, Faxon D, Holmes D, Bourassa M, Block P, Goss&n A, Bentivoglio L, Leather- man L, Dorms G, King S III, Galichia J, Al-Bassam M, Leon M, Robertson T, Pas- samani E. Percutaneous transluminal coronary angioplasty in 1985-1986 and 1977-1981. The national heart, lung, and blood institute registry. N Engl J Med 1988;318:265-270. 16. ‘Ihe principal investigators of CASS and their associates. The National Heart, Lung, and Blood Institute Coronary Artery Surgery Study (CASS). Circulation 1981;63(suppl 1):1-1-I-81. 17. Campeau L. Grading of angina pectoris. Circularion 1975;54:522-523. 18. Wenneker MB, Epstein AM. Racial inequalities in the use of procedures for patients with ischemic heart disease in Massachusetts. JAMA 1989;261:253-257. 1s. Ford E, Cooper R, Castaner A, Simmons B, Mar M. Coronary artwiography and coronary bypass survey among whites and other racial groups relative to hos- pit&based incidence rates for coronary artery disease: fmdings from NHDS. Am J Public Health 1989;79:4374Ul. 20. Goldberg KC, Hartz AJ, Jacobsen SJ, Kmkauer H, Rimm AA. Racial and com- munity factors influencing coronary artery bypass grati surgery rates for all 1986 Medicare patients. JAMA 1992;267:1473-1477.

1146 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 73 JUNE 15, 1994

percutaneous transluminal coronary angioplasty in african-american patients (the national heart,...

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