Measures of wave intensity as non-invasive surrogate for cardiac function predicts mortality in hemodialysis patients

Abstract

Background and hypothesis Risk prediction in hemodialysis patients is challenging due to the impact of the dialysis regime on patient's volume status and the complex interplay with cardiac function, comorbidities, and hypertension status. Cardiac function as a key predictor of cardiovascular mortality in hemodialysis patients is challenging to assess in daily routine. Thus, the aim of this study was to investigate the association of a novel, non-invasive relative index of systolic function with mortality and to assess its interplay with volume removal. Methods In total, 558 (373 male/185 female) hemodialysis patients with a median age of 66 years were included in this analysis. They underwent 24-hour ambulatory blood pressure monitoring including wave intensity analysis (i.e. S to D ratio (SDR)). All-cause and cardiovascular mortality served as endpoints, and multivariate, proportional hazards models were used for risk prediction. Intra-dialytic changes were analyzed in tertiles according to ultrafiltration volume. During a follow-up of 37.8 months, 193 patients died (92 due to cardiovascular reasons). Results SDR was significantly associated with all-cause (univariate HR = 1.36 [1.20–1.54]; p < 0.001) and cardiovascular (univariate HR = 1.41 [1.20–1.67]; p < 0.001) mortality. The associations remained significant in multivariate analysis accounting for possible confounders. Changes in SDR from pre-/early- to post-dialytic averages were significantly different for the three ultrafiltration volume groups. Conclusion This study provides well-powered evidence for the independent association of a novel index of systolic function with mortality. Furthermore, it revealed a significant association between intradialytic changes of the measure and intradialytic volume removal.