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 as ymptomatic aortic regurgitation. Background. We tested the hypothesis that early administration of a vasodilator drug might be able to reduc e left ventricular dilation and mass expansion. Because the renin angi otensin 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 ao rtic regurgitation were enrolled in a randomized, double-blind trial c omparing enalapril with hydralazine. All patients underwent serial non invasive studies. Seventy patients completed the 12-month follow-up. R esults. At 1 year, patients receiving enalapril had a significant redu ction in left ventricular end-diastolic and end-systolic volume indexe s (124 +/- 15 vs. 108 +/- 17 ml/m(2), p < 0.01; 50 +/- 12 vs. 40 +/- 1 4 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 signif icant changes. Both regimens not only had a significant reduction in l eft ventricular mean wall stress but also had a mild increase in exerc ise 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 m ean wall stress. Enalapril therapy achieves significant left ventricul ar mass regression, left ventricular end diastolic and end systolic vo lume index reduction and renin angiotensin system suppression. These f indings suggest that early unloading enalapril therapy has the potenti al to favorably influence the natural history of chronic aortic regurg itation.