PRECAPILLARY PULMONARY-HYPERTENSION OF UNCERTAIN ETIOLOGY

History and clinical findings: A 39-year-old man was hospitalized for investigation of increasing dyspnoea for 3 month. On admission he was found to have bilateral ankle oedema, an enlarged liver and loud systo lic murmur over the lower sternum. Investigations: There were signs of right heart strain/hypertrophy on the chest radiogram and echocardiog ram. After treatment of right heart failure cardiac catheterization in dicated moderate precapillary pulmonary hypertension (PH) with a mean pulmonary artery pressure (PAPm) of 24 mm Hg and pulmonary vascular re sistance (PVR) of 470 dyn . s . cm(-5) at rest. All known causes havin g been excluded, the PH was classified as idiopathic. Treatment and co urse: Evidence of acute pulmonary vascular reactivity was obtained wit h nitric oxide (NO) inhalation and oral diltiazem, a calcium-channel b locker. The latter, at a dosage of 3 x 120 mg daily, had after 13 days achieved a persisting reduction of PVR at rest and a reduction in PAP rise during exercise. Conclusion: After exclusion of other causes, th e acute right heart failure was found to be due to primary pulmonary h ypertension. The therapeutic efficacity of diltiazem as a vasodilator can be predicted from the response to inhaled NO.