Primary Pulmonary Hypertension

The clinical features of 16 patients with primary pulmonary hypertension are reviewed. Repeated cardiac catheterizations at intervals of 1 to 4 years during the course of the disease were performed in five patients. In three of the five patients there was a progressive increase in pulmonary artery pressure, total pulmonary resistance, and a decline in cardiac output. In two patients the pulmonary hemodynamics remained unchanged between studies at intervals of 2 and 4 years. Arterial oxygen saturation decreased with progression of the disease, presumably reflecting the appearance of an uneven distribution of pulmonary capillary flow. The course of the illness was variable and unaffected by any mode of therapy, including long-term anticoagulation.