Efficacy of captopril in low-renin congestive heart failure: Importance of sustained reactive hyperreninemia in distinguishing responders from nonresponders

To determine the efficacy of converting-enzyme inhibition in patients with low-renin congestive heart failure (CHF), the long-term hemodynamic and clinical responses to captopril were evaluated in 26 consecutive patients with severe, chronic CHF whose pretreatment plasma renin activity (PRA) was <2 ng/ml/hour. After 2 to 8 weeks of continuous treatment with captopril, 14 patients (54%) showed long-term hemodynamic benefits, of whom 13 (50%) improved clinically by at least 1 New York Heart Association functional class. To distinguish responders from nonresponders, patients were grouped based on the presence or absence of sustained reactive hyperreninemia (PRA during chronic therapy >4 ng/ml/hour). After 2 to 8 weeks of therapy with captopril, 14 patients had sustained reactive hyperreninemia. Their cardiac index increased by 0.33 liters/min/m² (p <0.01), left ventricular filling pressure decreased by 12.6 mm Hg (p <0.001), mean right atrial pressure decreased by 4.9 mm Hg (p <0.001) and systemic vascular resistance decreased by 529 dyne s cm^-5 (p <0.001). Twelve of these 14 patients patients improved clinically. Twelve other patients had no reactive increase in PRA, and these patients showed no significant improvement in any hemodynamic variable after 2 to 8 weeks of treatment with captopril; only 1 of the 12 patients improved clinically (p <0.001 between groups). The 2 groups were otherwise similar with regard to pretreatment demographic, hemodynamic and hormonal variables. Thus, many patients with severe, chronic CHF associated with a low PRA improve during therapy with captopril, and these patients can be distinguished from nonresponders by the occurrence of reactive hyperreninemia during long-term treatment.