Primary Pulmonary Hypertension

Primary pulmonary hypertension is a condition characterized by sustained elevations of pulmonary-artery pressure without a demonstrable cause. The diagnostic criteria used in the National Institutes of Health (NIH) registry 1 include a mean pulmonary-artery pressure of more than 25 mm Hg at rest, or more than 30 mm Hg with exercise, and the exclusion of left-sided cardiac valvular disease, myocardial disease, congenital heart disease, and any clinically important respiratory, connective-tissue, or chronic thromboembolic diseases. Pulmonary vascular disease with clinical and pathological features similar to those of primary pulmonary hypertension can occur in patients with portal hypertension, 2 infection with the human immunodeficiency . . .