Influence of a single dose of captopril on pulmonary haemodynamics and right ventricular function in mitral stenosis with pulmonary hypertension.
The response of the pulmonary circulation to captopril 75 mg has been examined in 21 patients with pulmonary hypertension secondary to mitral stenosis. The effects of captopril were measured every 15 min up to 2 h by recording pressures in the pulmonary and systemic circulations and by measuring cardiac output. Pulmonary artery systolic pressure fell significantly by 21.6% (from means = 54.6 to 42.8 mm Hg), pulmonary artery diastolic pressure by 23.3% (from 26.2 to 20.1 mm Hg), and the pulmonary artery mean pressure by 23.2% (from 36.9 to 28.3 mm Hg). Right ventricular end-diastolic pressure also fell significantly by 7% (8.1 to 7.5 mm Hg). Heart rate decreased by 6.5% (from 76.3 to 71.3 beats.min-1). Cardiac index and stroke volume index did not change. The total and vascular pulmonary resistance dropped significantly by 23.2% (from 721 to 553.7 dyn.s.cm-5) and 40% (from 287.2 to 172 dyn.s.cm-5), respectively. The right ventricular stroke work index fell by 33% (from 15.1 to 10.1 g/beat/m2). Systemic systolic pressure decreased by 10.5% (from 124.5 to 111.4 mm Hg). Thus, captopril lowered pulmonary pressures and resistances and no deterioration in right ventricular function was observed.