A comparison of enalapril plus hydrochlorothiazide with standard triple therapy in renovascular hypertension.

This prospective, double-blind, multicenter study compared enalapril plus hydrochlorothiazide with standard triple therapy (STT; hydrochlorothiazide, timolol, and hydralazine) with regard to safety, tolerability, antihypertensive efficacy, and effect on renal function in 75 patients with documented renovascular hypertension. Both groups showed a significant mean decrease in systolic and diastolic blood pressure during the double-blind study, with the enalapril group showing a mean 12 mm greater decrease in systolic blood pressure as compared to STT (less than 0.05). Effective treatment of diastolic hypertension was noted in 96% of the enalapril group as compared to 82% on STT (p less than 0.05). STT failure was seen exclusively in patients with bilateral renal artery stenosis of high grade and frequently in association with impaired renal function. cPAH, a measure of effective renal plasma flow, showed a significant increase in the enalapril group, as compared to the STT (p less than 0.05). In contrast, there was a bimodal response of CIn (GFR): 80% of patients in the enalapril group showed no significant change while 20% (10 patients) showed a mean decrease of 28% along with a 12% increase in CPAH (p less than 0.01). No acute renal failure or toxic side effects were noted in the enalapril group. Enalapril plus hydrochlorothiazide is very effective in treating renovascular hypertension and is without significant toxic side effects. The self-limited increase in serum creatinine seen in 20% of renovascular hypertensive patients receiving enalapril and hydrochlorothiazide may identify a subset of patients with unilateral or bilateral high grade renal artery stenosis who should be treated with angioplasty or operative intervention.