Abstract

BACKGROUND: Endothelin-receptor blockade provides haemodynamic benefit in experimental and clinical heart failure. We aimed to measure the effects of long-term endothelin-blockade on left-ventricular (LV) remodelling and clinical outcomes in patients with chronic heart failure.

METHODS: 642 patients with chronic heart failure were assigned the oral endothelin(A)-antagonist darusentan at 10, 25, 50, 100, or 300 mg daily or placebo for 24 weeks in addition to standard therapy in a randomised, double-blind, placebo-controlled trial. In the 50-300 mg groups, darusentan was uptitrated over 6 weeks. Primary endpoint was change in LV end-systolic volume (LVESV) at 24 weeks from baseline, measured by MRI. All patients for whom assessable MRI scans were available at baseline and follow-up were included in the analysis.

FINDINGS: Darusentan was well tolerated. LVESV could be assessed in 485 (76%) patients with paired MRI data at baseline and 6 months. The change in LVESV was not significantly different from that with placebo at any dose (mean difference from placebo 1.27 mL [95% CI -9.9 to 12.4] with 10 mg dose, -1.84 mL [-13.0 to 9.3] with 25 mg, -5.68 mL [-16.9 to 5.6] with 50 mg, -4.05 mL [-15.5 to 7.4] with 100 mg, and -4.34 mL [-15.7 to 7.0] with 300 mg). Heart failure worsened in 71 (11.1%) patients, and 30 (4.7%) died during the study with no difference between groups.

INTERPRETATION: Endothelin(A) blockade with darusentan did not improve cardiac remodelling or clinical symptoms or outcomes in patients with chronic heart failure receiving an angiotensin-converting-enzyme inhibitor, beta blocker, or aldosterone antagonist. Thus, endothelin(A) blockade is unlikely to be useful as an add-on treatment in such patients.