Deleterious Effects of Hydralazine in Patients with Pulmonary Hypertension

Abstract

Thirteen consecutive patients with primary and secondary pulmonary hypertension who had normal left ventricular function were treated with hydralazine in an effort to reduce pulmonary vascular resistance and clinical symptoms. Despite marked decreases in systemic vascular resistance (40 per cent; P<0.001), hydralazine produced only moderate decreases in pulmonary arteriolar resistance (21 per cent), without improving stroke volume or pulmonary-artery pressure. Instead, mean arterial pressure fell markedly (17.5 mm Hg, P<0.01) in association with a reflex increase in heart rate (11 beats per minute, P<0.01). Four patients became symptomatically hypotensive within 24 hours of the initiation of treatment; two of these four required pressors for circulatory support, and one died. Progressive renal insufficiency developed in one patient, and a symptomatic decrease in systemic arterial oxygen saturation occurred in another; both changes were reversed upon discontinuation of the drug.