Platelet aggregation in patients with primary pulmonary hypertension.

Platelet aggregation activity was investigated in patients with primary pulmonary hypertension in different stages of the disease. Platelets were activated with ADP and PAF. Spontaneous platelet aggregation was also measured. Spontaneous and low dose PAF-induced platelet aggregation in patients was greater than in healthy subjects and increased with the severity of the disease. It was concluded that the increased platelet activity can be related to unfavourable prognosis in these patients.