Platelet adhesiveness in myocardial infarction in relation to clinical course.

ADP-induced and whole blood platelet adhesiveness have been studied by repeated measurements during the acute stage of the disease and the following two months in 86 randomly selected patients admitted to a coronary care unit because of acute central chest pain. In the patients who developed ECG and enzyme changes typical of infarction (group 1), platelet adhesiveness was significantly increased on admission compared with the rest of the patients (group 2) and controls (group 3). Patients in groups 1 and 2 showed a secondary increase during the first week, but two months after admission the means had returned to values within the normal range. No correlation was found between platelet adhesiveness and infarction size or fatal outcome of the disease. Platelet adhesiveness did not differ between patients with ECG changes indicating a transmural infarct and those with mainly subendocardial infarction.