Previous research has documented racial differences in the use of invasive cardiac procedures. These patterns could be due to under-use in African American populations or over-use in white populations. This study examines the possible under-use of coronary revascularization procedures among different patient groups.

The study was conducted in six teaching hospitals in Los Angeles. All patients who underwent coronary angiography at a study hospital from January 1990 to September 1991 were identified, and, from among this group, 4,226 patients were randomly sampled. Only patients with coronary artery disease (CAD) were retained. Medical records were abstracted to determine whether patients met standardized (RAND) criteria for necessity of revascularization procedures and, if so, whether they underwent CABG or PTCA or were offered revascularization but refused.

In this sample, 55% of the patients were white, 21% were Latino, 12% were African American and 22% were other ethnicities. In bivariate analyses, no significant associations were seen between receipt of necessary CABG or PTCA and gender, ethnicity, or clinical presentation at the time of angiography. Patients with two-vessel disease were less likely than those with left main disease to undergo necessary CABG. Patients who underwent coronary angiography at a public hospital were less likely than those treated in a private hospital to undergo necessary PTCA. Rates of receipt of necessary CABG were similar at private and public hospitals (60% versus 58%).

Controlling for clinical covariates, left main disease was strongly associated with receipt of necessary CABG (OR=3.84; 95% confidence interval=2.13 to 6.92). No differences were observed between men and women or between patients who underwent coronary angiography in a private or public hospital. African Americans were less likely than whites to undergo necessary CABG (OR=0.49; 95% confidence interval=0.23 to 0.99). With respect to PTCA, clinical presentation with unstable angina or recent myocardial infarction and ejection fraction>=50% were strongly associated with receipt of necessary PTCA. African Americans were less likely than whites to undergo necessary PTCA (OR=0.20; 95% confidence interval=0.06 to 0.72). Patients who underwent coronary angiography at a public hospital were less likely than those at private hospitals to undergo necessary PTCA. There were no gender differences.

In this study, clinically significant under-use of revascularization procedures was not confined to the poor and uninsured (as measured by public versus private hospital use). According to the authors, "these findings suggests that elimination of financial barriers to care will not avert under-use of CABG and PTCA without attention to factors influencing clinical decision making and physician-patient communication. The provision of necessary revascularization was strongly driven by clinical factors. Nevertheless, non-clinical factors were also associated with under-use of CABG and PTCA." With regard to African Americans, refusal of recommended procedures, at least as documented in the medical records or reported by telephone survey responders, did not account for the racial disparities. The authors conclude that "more research is needed to understand and correct these apparent inequities, which may reflect real but unmeasured differences in patient preferences, bias in physician judgment or cultural barriers to physician-patient communication". Finally, the authors suggest that, if criteria for necessity of revascularization were incorporated into standard teaching and placed on hospital computers, patients needing revascularization would be identified more readily. "Clinicians could be supported and encouraged to offer necessary procedures…, or alternatively, to provide explicit clinical justification for not doing so in the medical record."