Exploring the Potential Synergistic Action of Spironolactone on Nitric Oxide-Enhancing Therapy: Insights From the African-American Heart Failure Trial

Background: To investigate if treatment with an aldosterone antagonist affects the outcomes of treatment by fixed dose combination of isosorbide dinitrate/hydralazine (FDC I/H) or placebo in black heart failure (HF) patients treated with contemporary HF medications. In the African-American Heart Failure Trial (A-HeFT), FDC I/H was effective in reducing mortality and improving event-free survival. The beneficial effects of aldosterone antagonist (spironolactone [SP]), however have not been adequately assessed in black patients with or without the use of FDC I/H. Methods and Results: A retrospective analysis was performed in A-HeFT data base (n = 1050) to determine the effect of using SP (39% of patients) on outcomes. Baseline comparisons were done by 2-sample t-test or Fisher's exact test. Kaplan-Meier survival analyses were used for comparing between and within groups for outcomes. SP had no effect on mortality, event-free survival, or first HF hospitalization in the overall A-HeFT population. However, SP decreased mortality risk in the FDC I/H group by 59% (P = .03), and a favorable trend was noted on event-free survival and first HF hospitalization. In contrast, the use of SP was not associated with a decrease in mortality or HF hospitalizations in the placebo group. Conclusions: This study suggests that in black patients with systolic heart failure on standard therapy of β-blockers and angiotensin-converting enzyme inhibitors/angiotensin receptor antagonists, the beneficial effects of aldosterone antagonists require a background therapy of FDC I/H.