Bucindolol, Systolic Blood Pressure, and Outcomes in Systolic Heart Failure: A Prespecified Post Hoc Analysis of BEST

Abstract

BackgroundIn the Beta-Blocker Evaluation of Survival Trial (BEST), systolic blood pressure (SBP) ≤ 120 mm Hg was an independent predictor of poor prognosis in ambulatory patients with chronic systolic heart failure (HF). Because SBP is an important predictor of response to β-blocker therapy, the BEST protocol prespecified a post hoc analysis to determine whether the effect of bucindolol varied by baseline SBP. MethodsIn the BEST, 2706 patients with chronic systolic (left ventricular ejection fraction < 35%) HF and New York Heart Association class III (92%) or IV (8%) symptoms and receiving standard background therapy were randomized to receive either bucindolol (n = 1354) or placebo (n = 1354). Of these, 1751 had SBP ≤ 120 mm Hg, and 955 had SBP > 120 mm Hg at baseline. ResultsAmong patients with SBP > 120 mm Hg, all-cause mortality occurred in 28% and 22% of patients receiving placebo and bucindolol, respectively (hazard ratio when bucindolol was compared with placebo, 0.77; 95% confidence interval [CI], 0.59-0.99; P = 0.039). In contrast, among those with SBP ≤ 120 mm Hg, 36% and 35% of patients in the placebo and bucindolol groups died, respectively (hazard ratio, 0.95; 95% CI, 0.81-1.12; P = 0.541). Hazard ratios (95% CIs; P values) for HF hospitalization associated with bucindolol use were 0.70 (0.56-0.89; P = 0.003) and 0.82 (0.71-0.95; P = 0.008) for patients with SBP > 120 and ≤ 120 mm Hg, respectively. ConclusionBucindolol, a nonselective β-blocker with weak α2-blocking properties, significantly reduced HF hospitalization in systolic HF patients regardless of baseline SBP. However, bucindolol reduced mortality only in those with SBP > 120 mm Hg.