The role of the renal resistance index in patients with heart failure with reduced or preserved ejection fraction.

Abstract Background Renal impairment is a common phenomenon that portends a poor prognosis of heart failure (HF). The renal arterial resistance index (RRI) can be useful for defining renal function and predicting outcomes in patients with HF. This study aimed to investigate the determining factors of the RRI in HF patients with preserved ejection fraction (HFpEF) and with reduced EF (HFrEF). Methods This retrospective study included 330 patients with HF. We investigated the determining factors for the RRI and the association between the RRI and 1-year composite outcome, comprising all-cause mortality and re-hospitalization for HF. Results The independent predictors of the RRI were tricuspid regurgitation peak gradient and estimated glomerular filtration rate in HFpEF, and pulse pressure and blood urea nitrogen in HFrEF. During the follow-up, 30 (9.1%) patients presented the composite outcome. Cox proportional hazard analysis revealed the association of the RRI with the composite outcome in both HFrEF (HR 1.08; 95% CI 1.03–1.14) and HFpEF (HR 1.07; 95% CI 1.03–1.12) without an interaction (p for interaction = 0.770). Conclusions The RRI was a consistent prognosticator in patients with HFpEF and those with HFrEF, while factors defining RRI were different between these groups.