PREDICTION OF RENAL IMPAIRMENT IN ELDERLY PATIENTS WITH CONGESTIVE-HEART-FAILURE TREATED WITH CAPTOPRIL

This study assessed the usefulness of the oral captopril test in the p rediction of renal impairment among elderly patients with congestive h eart failure (CHF). Forty-seven patients aged greater than or equal to 65 years with CHF (EF <40%) participated in a prospective nonrandomiz ed series. Blood samples for plasma renin activity (PRA) were drawn be fore and 60 minutes after 50 mg of oral captopril. Twenty-four hours l ater, captopril was administered (up to 75 mg/day over a 4 day period) , and renal laboratory and clinical assessment were performed at basel ine and for a 9 day period. In 7 of 47 patients (14.9%), deterioration of renal function was observed. During the captopril test, the PRA in creased significantly after 1 hour in almost all patients and the mean blood pressure decreased from 99.2 +/- 14.6 mmHg to 92.2 +/- 13.7 mmH g (p < 0.001). All patients whose baseline PRA level was <1.9 ng/ml/hr and whose stimulated PRA was <3.2 ng/ml/hr maintained a stable renal function throughout the study period. Significant statistical correlat ion (p < 0.05) was found between the initial PRA, the changes in PRA o r mean blood pressure during the captopril test, and the change in pla sma creatinine and creatinine clearance in the entire group, and was e ven more evident in a subgroup of patients with an ejection fraction g reater than or equal to 30%. All these correlations were not statistic ally significant in the patients with an ejection fraction <30%. It is thus concluded that measurement of pretreatment PRA levels might be a useful laboratory tool for predicting the renal safety of captopril u se in patients with CHF whose EF greater than or equal to 30%.