VASODILATOR THERAPY IN CHRONIC ASYMPTOMATIC AORTIC REGURGITATION - ENALAPRIL VERSUS HYDRALAZINE THERAPY

Objectives. This study attempted to evaluate the long-term efficacy of enalapril versus hydralazine therapy on left ventricular volume, mass and function as well as on the renin-angiotensin system in chronic asymptomatic aortic regurgitation. Background. We tested the hypothesis that early administration of a vasodilator drug might be able to reduce left ventricular dilation and mass expansion. Because the renin angiotensin system may be activated in chronic aortic regurgitation, early enalapril therapy might be beneficial. Methods. Between 1990 and 1993, 76 asymptomatic nonrheumatic patients with mild to severe chronic aortic regurgitation were enrolled in a randomized, double-blind trial comparing enalapril with hydralazine. All patients underwent serial noninvasive studies. Seventy patients completed the 12-month follow-up. Results. At 1 year, patients receiving enalapril had a significant reduction in left ventricular end-diastolic and end-systolic volume indexes (124 +/- 15 vs. 108 +/- 17 ml/m(2), p < 0.01; 50 +/- 12 vs. 40 +/- 14 ml/m(2), p < 0.01, respectively) and mass index (131 +/- 16 vs. 113 +/- 19 g/m(2), p < 0.01), whereas hydralazine therapy showed no significant changes. Both regimens not only had a significant reduction in left ventricular mean wall stress but also had a mild increase in exercise duration. Only enalapril therapy achieved a significant inhibition of the renin angiotensin system, in contrast to hydralazine therapy. Moreover, the multiple r(2) value from the analysis for end diastolic volume index using the two variables of age and treatment drugs was 72.1% (p < 0.01). Conclusions. Both regimens decrease left ventricular mean wall stress. Enalapril therapy achieves significant left ventricular mass regression, left ventricular end diastolic and end systolic volume index reduction and renin angiotensin system suppression. These findings suggest that early unloading enalapril therapy has the potential to favorably influence the natural history of chronic aortic regurgitation.