Scott NA, Kelsey SF, Detre K, Cowley M, King SB.
Percutaneous transluminal coronary angioplasty in African-American patients (the National Heart, Lung, and Blood Institute 1985-1986 Percutaneous Transluminal Coronary Angioplasty Registry)
Am J Cardiol 1994;73(16):1141-6.

The purpose of this study was to assess the outcome of black compared with white patients treated with coronary artery angioplasty (PTCA). Subjects were identified from the National Heart, Lung, and Blood Institute PTCA Registry, which enrolled consecutive patients who underwent their first PTCA during the period from August 1985 to May 1986. Patients were registered if they were patients of the study investigators; the sample included patients treated a total of 16 clinical centers.

Fifty-six percent of the black patients were treated at one of the 16 clinical centers; eight of the centers treated up to ten black patients; and seven centers treated no black patients. There were a number of demographic and clinical differences between the blacks and whites. Seventy-five percent of the white patients were men, while there was an equal gender distribution among blacks who underwent angioplasty. Unstable angina was a more frequent complaint of blacks than whites. Blacks were twice as likely to have a history of diabetes, three times as likely to have hypertension, and twice as likely to be cigarette smokers. There were no differences in the presence of hypercholesterolemia, history of congestive heart failure, or family history of CAD. The percentage of patients who were designated inoperable or high-risk surgical candidates was also similar for both groups.

There were no racial differences in risk factors once gender and clinical site were taken into consideration. Blacks were more likely to have triple vessel disease than whites, but there was no racial difference in the number of lesions attempted or in the number of vessels that were treated with PTCA. There was a striking absence of racial differences in a number of other clinical measures. (These data were unadjusted for clinical site.)

There was no difference in the incidence of death at 5 years. However, at the 5-year follow-up point, relatively fewer black than white patients reported no angina (6% versus 81%). When improvement was defined as no angina or angina less severe than before the initial PTCA, rates of improvement among black and white patients were nearly the same (89% versus 91%). However, black patients were also more likely to reported retirement due to a cardiac disease both before PTCA (9% versus 6%) and at the 5-year follow-up point (13% versus 8%).

The authors note that the proportion of black patients who underwent PTCA outside of the one site treating more than 50% of the black patient was far less than expected (given the proportion of black patients in the metropolitan areas where the clinical centers were located). They suggest that bias in the referral of patients to these centers is the most likely explanation; however, the possibility of extremely low rates of PTCA among blacks in these centers cannot be excluded. Such bias might influence other studies that report racial patterns for risk factors, as this study demonstrated such racial patterns disappeared after adjusting for clinical site.

The authors conclude that, despite having more co-morbidity and more coronary risk factors, blacks undergo successful coronary angioplasty procedures and have excellent long-term outcome as often as whites. "The reluctance to perform PTCA in this patient group may be unfounded."