This article examines the sequence of events leading to the use of revascularization procedures – both bypass surgery and angioplasty – in patients hospitalized with acute myocardial infarction. Evaluation is divided into four phases: pre-hospital, intra-hospital (initial hospitalization), inter-hospital (immediate transfer), and post-hospital.

Data were drawn from the 1991 hospital discharge abstract data obtained from the Office of Statewide Health Planning and Development of the State of California. Subjects analyzed consisted of black, white, and Hispanic patients who were admitted during the period between March 1991 and October 1991 with a principal diagnosis of acute myocardial infarction (AMI). Patients retained included those who were not Medicare enrollees, had a length of stay greater than five days, had not been recently admitted for the same diagnosis, and were less than 65 years of age.

Race, payor status, and initial disease severity were all strongly associated with revascularization during each period following infarction, and gender had a weaker association. The adjusted results were similar. In the pre-hospital phase, race was not associated with admission to a hospital offering revascularization, but payor class was (the privately insured had increased odds in comparison to uninsured persons or persons insured by HMO/prepaid health plans). Within hospitals offering revascularization, whites were the most likely to receive revascularization. Private patients also received revascularization at the highest rate, followed by HMO/prepaid health plan subscribers. Medicaid and uninsured patients were the least likely to be treated with revascularization upon admission to a high technology hospital. With regard to the inter-hospital phase, whites were also more likely to undergo transfer and subsequent revascularization than were minority patients. Privately insured patients show the highest probability of being transferred and revascularized, and Medicaid patients and the uninsured had the lowest. Post-hospital, this pattern was repeated.

In the subgroup of patients who received cardiac catheterization, race was a significant predictor of "converting" a catheterization procedure to a revascularization procedure (adjusted OR for whites versus non-whites=1.49), as was payor class. Gender was not a significant predictor of conversion. These results are consistent with those found for the total sample.

During the index admission, 5.6% of the patients died. During the index and transport admission combined, 6.1% of the patients died. Use of revascularization was strongly associated with a reduced probability of death during the index and transport admission combined (adjusted OR for death in patients with revascularization versus those without was 0.40).

Privately insured and HMO/prepaid health plan patients were more likely to survive than Medicaid and uninsured patients. However, because the odds ratios comparing various insurance groups were nearly identical in the analyses that adjusted for revascularization status and those that did not, one cannot conclude that the short-term survival advantage of insured patients resulted from greater access to revascularization procedures. Other analyses confirmed that the association between insurance and payor status was not mediated by access to revascularization.

In sum, there was evidence of race differences during many phases. Because there was a strong association between race and payor class and the probability of progressing through many phases in the sequence leading to revascularization, the authors explored the probability that a "generic" white patient and “generic” black patient (assigned the average value of covariates for gender, payor status, severity and age) would receive revascularization. It is notable that baseline racial differences in revascularization rates were not diminished substantially during any particular phase. However, when the impact of race was equalized for both the intra- and inter- hospital phase, racial discrepancies were nearly eliminated.

The authors conclude, "Discrepancies in the service utilization between groups that have been described in prior cross-sectional studies are the end result of a complex series of events. Implementing programs to ensure equitable and appropriate care at multiple points in the sequence of care will probably be most effective in ensuring the better quality cardiac care is provided without complex health system." The authors also note that this analysis "leaves unresolved the issue of whether patient, physician, or institutional factors underlie the observed differences at each step of the sequence."