Key result
Hydralazine-isosorbide dinitrate linked to ~29% lower all-cause death in heart failure patients.
Why the trial?
Randomised trials of hydralazine-isosorbide dinitrate in heart failure span five decades and differ in populations and background therapy. Pooling them clarifies whether the combination reduces mortality across historical and contemporary settings.
Does hydralazine-isosorbide dinitrate reduce mortality in patients with heart failure with reduced ejection fraction?
Design limitations
substantial heterogeneity in trial design, follow-up duration and background therapy across the pooled trials.
Statistical certainty
heart-failure hospitalisation results were inconsistent across trials with no pooled estimate reported, and the investigators themselves concluded that firm conclusions about cardiovascular outcomes are difficult.
Patient burden
tolerability issues with H-ISDN complicate interpretation of the mortality findings.
Does hydralazine-isosorbide dinitrate reduce mortality in patients with heart failure with reduced ejection fraction?
Hazard Ratio: 0.71 (95% CI 0.58–0.87)
Although hydralazine-isosorbide dinitrate is associated with reduced all-cause and cardiovascular mortality in HFrEF, significant trial heterogeneity and tolerability issues prevent firm clinical conclusions.
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Experts see the H-ISDN meta-analysis mortality signal as noteworthy but are cautious, given a neutral individual trial (H-HeFT) and acknowledged heterogeneity that makes firm practice conclusions difficult.
The meta-analysis pooling three trials showed meaningful reductions in all-cause and cardiovascular death with hydralazine-isosorbide dinitrate, but the largest new trial (H-HeFT) missed its primary endpoint on its own. Expert commentary has focused on summarizing the findings rather than taking strong stances, and no one has called this practice-changing. The open question is whether these pooled mortality results are robust enough to shift guideline recommendations beyond the current race-based indication.
It remains unclear whether guideline committees will broaden the H-ISDN indication to a wider HFrEF population based on the pooled mortality data, especially given that H-HeFT alone was neutral and hospitalization results were inconsistent. No expert has weighed in on whether the heterogeneity in trial design and background therapy undermines the meta-analytic signal enough to warrant further study.
“H-ISDN meta-analysis — In patients with HFrEF in randomised trials of hydralazine–isosorbide dinitrate, hydralazine–isosorbide dinitrate reduced clinical outcomes compared with control.”
Gibson discussed both the neutral H-HeFT trial (stopped early, no reduction in the primary composite) and the meta-analysis showing significant reductions in all-cause death, CV death, and first HF hospitalization across three pooled RCTs. His posts served as interview-based summaries with linked video and slides.
Gulati reported the H-HeFT results, noting 592 patients were randomized to H-ISDN versus placebo and the primary endpoint was not met (HR 0.90, 95% CI 0.67-1.21). Her post highlighted the neutral finding without editorializing on its implications.
May support use in ACEI-intolerant HFrEF; leaves open net benefit in contemporary regimens due to heterogeneity.
This meta-analysis pooled three randomised trials of hydralazine-isosorbide dinitrate in heart failure, including A-HeFT and H-HeFT, covering 2,101 patients. H-ISDN was associated with a reduction in all-cause death (HR 0.71, 95% CI 0.58 to 0.87) and cardiovascular death (HR 0.65, 95% CI 0.47 to 0.90), while results for heart-failure hospitalisation were inconsistent across trials. Substantial differences in trial design, duration of follow-up and background therapy were noted. Presented in Hot Line 6 at ESC Congress 2026, the investigators concluded that given the heterogeneity and the tolerability issues it is difficult to make firm conclusions about the effect of H-ISDN on cardiovascular outcomes. Source: ESC Congress 2026 press release, 30 August 2026.
Morten Schou (2026) conducted a meta-analysis in Heart failure with reduced ejection fraction (n=2,101). Hydralazine-isosorbide dinitrate (H-ISDN) was evaluated on All-cause death (HR 0.71, 95% CI 0.58-0.87). Hydralazine-isosorbide dinitrate was associated with a reduction in all-cause death (HR 0.71; 95% CI 0.58-0.87) and cardiovascular death (HR 0.65; 95% CI 0.47-0.90).
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