Given the scarcity of data on the pathogenesis of ischemic heart disease in blacks, this study sought to describe the clinical and angiographic findings in black patients with suspected coronary artery disease. The sample included all black patients who underwent cardiac catheterization primarily for suspected coronary artery disease from 1992 to 1994 in Cook County hospital, a public hospital serving the urban population of Chicago. Only patients who had not undergone previous angiography or bypass surgery were included.

Of this group, 32% of the patients had normal coronary angiograms, and an additional 15% had less than 50% stenosis in any of the major vessels. Among the others, 37% had one-vessel disease, 29% had two-vessel disease, and 33% had three-vessel disease. Only one patient had isolated left main coronary artery disease. The mean left ventricular ejection fraction was 0.50. As expected, hypertension, diabetes mellitus, cigarette smoking, history of congestive heart failure, and prior history of myocardial infarction were significantly more frequent in patients with obstructive coronary artery disease. Unstable angina as initial presentation was more common in patients with obstructive coronary artery disease, whereas chronic stable angina as initial presentation was more common in patients without obstructive coronary artery disease.

The authors draw several conclusions about black-white differences based on these data and previous studies: (1) black patients who undergo coronary angiography for suspected coronary artery disease have normal coronary angiogram or non-obstructive coronary artery disease more often than white patients; (2) when obstructive coronary artery disease is present, the distribution of 1-, 2-, and 3-vessel disease is similar in black and white patients; and (3) there are racial differences in the prevalence of conventional risk factors for coronary artery disease (hypertension, obesity, diabetes, and smoking). It would obviously be important to have a white comparison group appropriate for this sample of black patients in order to draw any conclusion about racial differences for any of the above factors.