Platelet aggregation across the myocardial vascular bed in man: I. Normal versus diseased coronary arteries.

Abstract Platelet aggregation studies were performed in aortic and coronary venous blood in 28 patients with coronary artery disease. Mean platelet aggregation was significantly lower in coronary venous blood compared to aortic blood using epinephrine and ADP as aggregating agents. Platelet counts were also found to be lower in coronary venous blood. Platelet aggregation was lower in both aortic and coronary venous blood in 12 of these patients who were taking propranolol compared to the other 16 patients not taking propranolol. Six other patients without angiographic evidence of coronary disease exhibited no change in platelet aggregation or counts across the myocardial vascular bed. These data indicate that platelet aggregation is lower in coronary venous blood in patients with coronary disease. Propranolol decreases aggregation in aortic as well as coronary venous blood. Lower platelet aggregation in coronary venous blood may be in part related to removal of reactive platelets or formation of platelet aggregates in the diseased coronary vasculature.