Effect of platelet suppressant treatment with dipyridamole and aspirin on exercise performance and platelet survival time in coronary disease.

Platelets may contribute to the pathogenesis of atherosclerotic coronary artery disease (CAD), and platelet reactivity may be activated by exercise. Fourteen men with CAD participated in a double-blind, crossover study of aspirin (ASA), dipyridamole (DPY), ASA-DPY, and placebo. The ASA therapy increased platelet survival time (autologous labelling with 51Cr), but had no effect on either the duration of angina-limited treadmill exercise or the heart rate-systolic blood pressure product (x 10(-2)) at peak exercise. The combination DPY-ASA had a greater effect on platelet survival, but did not substantially increase the duration of exercise. Administration of DPY alone at a higher dosage increased the exercise duration and had a similar effect on platelet survival. At the time that control exercise was completed with the higher dosage of DPY, the rate-pressure product was decreased. The results suggest that DPY and ASA favorably alter the platelet survival in men with CAD, and that DPY, but not ASA, favorably alters exercise performance. Although ASA and ASA-DPY may alter platelet response to exercise, the effect is not shown in hemodynamic measurements during exercise. In higher dosages, DPY may be an effective coronary vasodilator for men with CAD.