Increased mean platelet volume after acute myocardial infarction relates to diabetes and to cardiac failure.

Mean platelet volume, platelet count and an estimate of platelet volume distribution were studied following acute myocardial infarction in 59 diabetics and 88 non-diabetics and were compared with values in 100 non-diabetic and 50 diabetic non-infarct subjects. In the non-diabetics mean platelet volume and platelet distribution width were similar in the non-infarcted patients and in the infarcted patients without severe cardiac failure. All diabetics with myocardial infarction had larger mean platelet volumes and platelet distribution width than the diabetic non-infarct controls. All myocardial infarction patients with severe cardiac failure had larger platelet volumes than patients with mild or no failure. Increased mean platelet volume may reflect either increased platelet activation or increased numbers of large, hyperaggregable platelets. Abnormalities of platelet function may contribute to the relatively poor prognosis of myocardial infarction in patients with diabetes.