Several studies have documented lower rates of revascularization in black patients with coronary artery disease; however, there are few data to explain these differences. This study assesses whether differences in clinical presentation explain the differences in the use of coronary-artery bypass surgery (CABG) or percutaneous transluminal coronary angioplasty (PCTA) for black versus white male patients admitted with acute myocardial infarction or unstable angina. Analyses were based on the appropriateness of these two procedures as rated by the RAND criteria.

Patients were selected from six Veterans Affairs medical centers across the country. Each site had the capacity to perform CABG onsite or at an adjacent university hospital. Patients included in the study sample were admitted between October 1, 1989 and September 30, 1995 and were selected to ensure sufficient representation based on age, medical center, primary diagnosis, year of discharge, and race. Patients having undergone a previous revascularization procedure were excluded. Of 3,137 potentially eligible patients, 535 were black; for these patients, 414 (77%) of the medical records were available. A white patient was matched to each black patient; if medical records were unavailable for a matched white patient, another patient was selected. In total, 710 medical records for white patients were requested and 517 (73%) were received. After excluding ineligible patients, 666 veterans (326 blacks and 340 whites) were assessed in this study.

There were few racial differences in clinical characteristics; however, blacks had less severe coronary artery stenoses, and white patients were more likely to have unstable angina. Both among patients with acute MI and patients with unstable angina, fewer blacks had angiographically demonstrated coronary artery lesions. Blacks were more likely to have hypertension, diabetes mellitus, and current or past alcohol abuse.

During the 90 days following catheterization, 108 (16%) of the 666 patients underwent CABG. During the 60 days following catheterization, 146 (22%) of the 666 patients underwent PTCA. Three patients underwent both procedures. Black patients were less likely than whites to undergo any procedure (28% versus 47%, p<0.001). When only patients with angiographically demonstrated coronary artery lesions were considered, the racial differences in revascularization rates persisted (38% versus 54%, p<0.001). Overall, the unadjusted odds ratio (OR) for blacks versus whites was 0.48 (95% confidence interval=0.32 to 0.70) for undergoing PTCA and 0.38 (95% confidence interval=0.24 to 0.60) for undergoing CABG.

Forty-eight percent of those for whom PTCA was necessary had the procedure (54% of whites and 37% of blacks). Alternately, 36% of those for whom neither PTCA not CABG were necessary had PTCA (42% of whites and 49% of blacks), and 46% of those for whom these procedures were rated as "equivocal" had PTCA (37% of whites and 16% of blacks). Forty-three percent of those for whom CABG was necessary had the procedure (52% of whites and 32% of blacks). Very few blacks for whom these procedures were rated as unnecessary or equivocal underwent CABG. Multivariate analyses were conducted for patients within each appropriateness rating level, controlling for admit diagnosis, site, alcohol abuse, year, Charlson score, and Parsonnet score (and that only included patients with demonstrated coronary artery lesions). Blacks were significantly less likely to receive CABG when only CABG was rated as necessary (OR=0.42, 95% confidence interval=0.20 to 0.86). For patients with equivocal or inappropriate RAND indications, race was the only statistically significant predictor of PTCA (data not presented). Finally, there was no difference in 1-year and 5-year mortality between blacks and whites.

The authors conclude that black patients underwent CABG and PTCA less often than white patients and that racial differences in clinical factors do not fully explain the black-white difference in this cohort of patients with acute MI or unstable angina. For PTCA, the racial differences were largest when indications for PTCA were equivocal. However, for CABG, even when CABG was necessary and appropriate, black patients still did not undergo the procedure at the same rate as white patients. They note, "It is unclear whether the disparity in procedure use affects patient outcome…If this difference in procedure use reflects poorer access to procedures that may have lifesaving benefits, then prompt action to increase access for blacks seems warranted. If this difference exists because white patients who have equivocal indications for surgery are more likely to elect revascularization than similar blacks, then this difference may simply reflect differences in attitudes and preferences toward invasive procedures…Future studies should directly address the physician-patient interactions that lead to physician decisions to offer revascularization and patient decisions to accept it. This would include attention to patient preference, physician-patient communication and trust."