Regression in thromboembolic type of primary pulmonary hypertension during 2 1/2 years of antithrombotic therapy.

Primary pulmonary hypertension carries a poor prognosis, with a 5 year survival rate of less than 25%. However, a previous study of more than 100 patients with tissue-proved primary pulmonary hypertension suggested that antithrombotic therapy may have a beneficial effect on survival, especially in patients with the thromboembolic type of primary pulmonary hypertension. This report describes a 54 year old white man with primary pulmonary hypertension of the thromboembolic type (proved by right upper lobe lung biopsy) who, after long-term antithrombotic therapy, showed resolution of symptoms of dyspnea and fatigue, regression of electrocardiographic signs of right ventricular hypertrophy and regression of elevated pulmonary artery pressure. Base-line cardiac catheterization in January 1982 revealed elevated pulmonary artery pressure (104/37 mm Hg) and pulmonary vascular resistance (14.6 units/m2) that did not decrease with 100% oxygen or intravenous hydralazine (12 mg). The patient was treated with warfarin and dipyridamole, 100 mg four times daily. The most recent cardiac catheterization in January 1984 revealed a pulmonary artery pressure of 50/15 mm Hg and a pulmonary vascular resistance of 8.7 units/m2. It is believed that this is the first report of regression of the symptoms and signs of biopsy-proved primary pulmonary hypertension. In view of the lack of a response to vasodilators in 1982, it is suggested that antithrombotic therapy is partially responsible for the improvement of this patient.