Production of circulating platelet aggregates by exercise in coronary patients.

To determine the effect of exercise on the in vivo formation of circulating platelet aggregates in patients with severe coronary artery disease (CAD), platelet aggregate ratios (PAR) (normal 0.8-1.1)were measured immediately before and after treadmill exercise and 30 minutes after exercise in 17 CAD patients (group 1, mean age 55 years), 12 age-matched normal subjects (group 2), and 13 young normals (mean age 27 years, group 3).Coronary patients had lower resting PAR than group 3 (0.79 ± 0.05 vs 0.98 ± 0.03; p 0.05 vs CAD and group 3).Immediately after exercise, group I PAR declined from 0.79 i 0.05 to 0.53 ± 0.04 (p 0.05; both p 0.05; both p 0.05) from resting values without aspirin.The exercise-induced decline in PAR was attenuated by aspirin: without aspirin, 0.73 ± 0.02 preexercise to 0.54 ± 0.04 postexercise; with aspirin, 0.73 ± 0.03 to 0.82 ± 0.03 (p < 0.05 vs no aspirin).These data indicate that platelet aggregation occurs with exercise in CAD.In addition, these data suggest that aspirin exerts a significant inhibitory effect on exercise-induced platelet aggregation in CAD patients.