Racial differences in platelet survival time in patients with symptomatic coronary atherosclerosis.

Platelet survival times were studied in 40 patients (21 white and 19 black) with coronary artery disease and stable effort induced angina pectoris. The platelet survival times of 19 white controls (9.27 +/- 0.49 days; mean +/- SD) were not significantly different from those of 12 black controls (8.88 +/- 0.81 days), and the platelet survival times for 21 white patients with coronary artery disease (8.46 +/- 0.65 days) were lower than the times for both the white controls (p less than 0.01) and the combined control group (p less than 0.01). However, the difference between the mean platelet survival times of 19 black patients (9.22 +/- 0.68) and the control groups was not significant, and the difference between the mean platelet survival times of the 21 white patients and the 19 black patients was significant (p less than 0.01). Stepwise multiple linear regression analysis indicated that race was the most significant factor in predicting shortened platelet survival (r = 0.4783; p less than 0.01). It is concluded that racial background should be considered in the interpretation of platelet studies and that reported racial differences in the rate and extent of atherosclerotic lesions may be related to racial differences in platelet consumption.