Association of renal resistance index and arterial stiffness on clinical outcomes in patients with mild-to-moderate renal dysfunction and presence or absence of heart failure with preserved ejection fraction

The renal arterial resistance index (RI) and the brachial–ankle pulse wave velocity (baPWV) are known as indicators of renal vascular resistance/systemic vascular damage and systemic arterial stiffness. The clinical significance of those parameters on clinical outcomes is poorly known in patients with and without heart failure with preserved ejection fraction (HFpEF). Baseline clinical data and the RI assessed by renal Doppler data, baPWV were obtained in patients with (HFpEF group, n = 60) and without HFpEF (non-HFpEF group, n = 51) who had a reduced estimated glomerular filtration rate (eGFR) of > 30 and < 60 mL/min/1.73 m²). We investigated the association between the RI and baPWV and major clinical outcomes including hospitalization for heart failure, cardiovascular death, myocardial infarction or unstable angina or other cardiovascular events and death from another cause. The RI and baPWV were greater in the HFpEF group than in the non-HF group (0.75 ± 0.07 vs. 0.69 ± 0.08, p < 0.001; 2002 ± 430 vs. 1762 ± 300 cm/s, p = 0.001). The RI correlated significantly with baPWV in the HFpEF (r = 0.382, p = 0.003) and non-HFpEF groups (r = 0.414, p = 0.002). During the median follow-up period of 54 months, major clinical outcomes occurred in 41 (36.9%) patients. The RI value, statin use and the presence of HFpEF were major factors for predicting clinical outcomes by multivariate analysis. Among the patients who had mild-to-moderate renal dysfunction, an increased RI and baPWV were observed in HFpEF patients as compared to non-HFpEF patients, but the baPWV similarly correlated with the RI value regardless of HFpFE patients or not. The strong association between the high RI value and presence of HFpEF and major clinical outcomes, suggests that not only the presence of HFpEF but also the high RI value may help to identify the high-risk patients leading to poor clinical outcomes.