Pulmonary hypertension in polycythemia vera.

Thromboembolic events occur in about 27% of the patients with polycythemia vera and account for 31% of the deaths. These include cerebrovascular accidents, myocardial infarction, peripheral vascular occlusions, pulmonary infarctions, and venous thrombosis. We report two cases with polycythemia vera who presented with pulmonary hypertension in the absence of previous thromboembolic complications of any kind. One patient died suddenly, with evidence of extensive bilateral thrombosis of prelobular pulmonary arteries at autopsy. In the second patient, local thrombosis in the pulmonary vasculature or recurrent silent pulmonary emboli appear to be responsible for the development of pulmonary hypertension. After institution of anticoagulant therapy, he is able to maintain his functional status. The purpose of this report is to alert clinicians to the development of this insidious, but potentially fatal complication in patients with polycythemia vera.