[The effects of enalapril on exercise capacity and right ventricular function in patients with chronic cor pulmonale]

Chronic cor pulmonale (CPC) in patients with chronic obstructive pulmonary disease (COPD) is a predictor of mortality. ACE inhibitors (ACEIs) improve the symptoms and reduce mortality of left ventricular or congestive failure, however their long term use in patients with CPC has not been tested. The aim of this study is to assess the effect on exercise tolerance and cardiorespiratory function of long term administration of enalapril in patients with CPC.

Placebo-controlled, double blind, randomized study. 28 patients (24 men and 4 women, mean age of 68.11 +/- 7.78, range 51-79) with CPC and without exacerbation of their respiratory symptoms at baseline were double blind randomised to receive enalapril or placebo for 6 months, added to their previous therapy. Respiratory function test, exercise tolerance ("six minutes walking test") and isotopic ventriculography were performed at baseline and at the end of the study.

At baseline there were no differences in FEV1, FVC, FEV1/FVC and exercise tolerance. Both placebo and enalapril were well tolerated. At the end of the study, patients taking enalapril increased their exercise tolerance an 8.9% (19 m) vs 4.7% (33 m) in the placebo group (p 0.44; 95 percent confidence interval, -41.10 to 91.99). RVEF improved a 6.4% with enalapril but worsened a 7.09% in placebo group (p 0.15; 95 percent confidence interval, -12.87 to 2.10).

Long term administration of enalapril do not improve neither exercise tolerance, nor right ventricular (RV) function, although given in increasingly doses is well tolerated and might prevent further worsening in RV systolic function.