Renal protective effect of strict blood pressure control with enalapril therapy.

The effect of strict blood pressure control on progression of renal disease in patients with essential hypertension has not been well defined. We have followed prospectively for three years 23 patients with essential hypertension. Blood pressure was well controlled on either enalapril or enalapril-hydrochlorothiazide therapy. Yearly assessment of renal function revealed no change in glomerular filtration rate as assessed by creatinine or inulin clearance, and a sustained 17% increase in effective renal plasma flow. In patients with moderately impaired renal function (inulin clearance less than or equal to 1.33 mL/s [80 mL/min]), there was a first-year 50% increase in inulin clearance, and a 33% increase in inulin clearance at year three. In these patients, there was a 39% first-year increase in effective renal plasma flow, which was sustained at year three. Filtration fraction and urinary protein excretion were unchanged. These results suggest that long-term blood pressure control with the angiotensin-converting enzyme inhibitor enalapril or enalapril-hydrochlorothiazide is associated with preservation and/or improvement in renal function.