EFFECTS OF CAPTOPRIL AND ENALAPRIL ON RENAL-FUNCTION IN ELDERLY PATIENTS WITH CHRONIC HEART-FAILURE

Objective: To compare the effects on renal function of captopril and e nalapril in elderly patients with chronic heart failure. Design: A mul ti-centre double-blind parallel-group comparison of the two angiotensi n-converting enzyme (ACE) inhibitors, captopril (12.5 mg bid) and enal april (2.5 mg bid). Subjects: 80 elderly patients with chronic heart f ailure (41 in the captopril group, 39 in the enalapril group). Main ou tcome measures: The blood pressure and pulse rate response to the firs t dose of ACE inhibitor was assessed in all patients. Glomerular filtr ation rate (GFR) was measured radioisotopically by 99mTcDTPA or 51CrED TA clearance after three and six months of each treatment. Subgroups w ere assessed for effective renal plasma flow (33 patients), exercise t olerance (25 patients) and by a symptom-oriented questionnaire (45 pat ients). Results: No serious adverse effect on GFR was noticed. There w as no significant difference between the two treatments in the mean ba seline GFR or in changes from baseline at three and six months (captop ril mean baseline GFR 49.6 ml min(-1) 1.76 m(-2), enalapril 54.7 ml mi n(-1) 1.76 m(-2); mean change (95% confidence interval) at three month s captopril 12 ml min(-1) (+3.0, +21.0), enalapril -2 ml min(-1) (-13. 0; +9.0); mean change at six months, captopril 3.7 ml min(-1) (-6.7; 14.2), enalapril -6.0 ml min(-1) (-21.0; +9.4). Significantly more pat ients given captopril had an improvement in GFR during the study perio d (26/31 compared with 20/31 enalapril-treated patients at three month s, p = 0.0096, and 23/30 compared with 15/27 at six months, p = 0.021) . There were no significant changes in effective renal plasma flow. Th ree patients treated with enalapril developed symptomatic hypotension within three days of starting treatment. Quality of life questionnaire s revealed more gastrointestinal symptoms in the enalapril group (p = 0.039). Conclusions: Captopril seems marginally preferable to enalapri l in the treatment of chronic heart failure in elderly patients.