Influence of ACE inhibition on pulmonary haemodynamics and function in patients in whom beta-blockers are contraindicated

Abstract

The effects of captopril have been studied in 19 patients suffering from chronic obstructive pulmonary disease (COPD). In 9 of these patients with pulmonary hypertension (mean pulmonary artery pressure greater than 20 mm Hg), we studied the effects of the drug on pulmonary haemodynamics, blood gases and systemic circulation. Haemodynamic data were recorded before oral captopril 50 mg and for the next 60 minutes. Following captopril administration, significant reductions in mean pulmonary artery pressure (PAP) (P less than 0.05), in mean pulmonary wedge pressure (PWP) (P less than 0.05) and in total pulmonary resistance (TPR) were noted; significant reductions in mean brachial artery pressure (BAP) and systemic vascular resistance (SVR) were also recorded, while cardiac output, heart rate and blood gas tensions showed no significant changes. Furthermore, the higher the hypoxaemia was, the greater the reduction in BAP (P less than 0.05). In the other 10 COPD patients with moderate essential hypertension, captopril was given as monotherapy (75-10 mg/day) for 60 days. We found no significant modification of the various respiratory function tests except for an increase in the vital capacity (P less than 0.05). Systolic blood pressure and diastolic blood pressure were reduced both in the supine and in the standing position and there were no side effects, in particular no bronchospasm even in the patients responsive to bronchodilator drugs. Our data suggest that captopril is an effective and safe drug when administered to COPD patients with essential hypertension. Moreover, in these patients, it may protect the pulmonary circulation from hypoxic pulmonary vasoconstriction.