Sildenafil in primary pulmonary hypertension.

To the Editor: A 21-year-old man presented with a three-year history of worsening dyspnea and a four-month history of being unable to walk more than 100 yards (90 m) without resting. Physical examination revealed signs of pulmonary hypertension. A chest radiograph showed the typical changes associated with primary pulmonary hypertension. An echocardiogram obtained at the time of admission showed marked right ventricular dilatation; the estimated pulmonary-artery systolic pressure was 120 mm Hg (resulting from tricuspid regurgitation identified on Doppler ultrasonography). Left ventricular systolic function was preserved. Pulmonary-function tests showed only mild airflow limitation. A computed tomographic scan of the thorax . . .