Effect of ultrafiltration on cerebral small-vessel disease and related outcomes in hemodialysis

BACKGROUND: Increasing evidence suggests a high prevalence of cerebral small-vessel disease (CSVD) in hemodialysis patients. Variable ultrafiltration during hemodialysis may contribute to brain lesions by inducing hemodynamic instability. We aimed to investigate the effect of ultrafiltration on CSVD and relative outcome in this population. METHODS: In a prospective cohort of maintenance hemodialysis adults, three features of CSVD including cerebral microbleed (CMB), lacunae and white matter hyperintensity (WMH) were measured by brain magnetic resonance imaging. Ultrafiltration parameters included the difference between annual average ultrafiltration volume (UV, kg) and 3%–6% of dry weight (kg), respectively, and the percentage of UV to dry weight (UV/W). The effect of ultrafiltration on CSVD and the risk of cognitive decline were investigated by multivariate regression analysis. Cox proportional hazards model was used to assess mortality over 7 years of follow-up. RESULTS: In the 119 study subjects, the frequency of CMB, lacunae and WMH was 35.3%, 28.6% and 38.7%, respectively. All ultrafiltration parameters were associated with the risk of CSVD in the adjusted model. There was a 37%, 47% and 41% greater risk of CMB, lacunae, and WMH, respectively, per 1% increment of UV/W. Ultrafiltration showed different effects on different distributions of CSVD. Restricted cubic splines depicted a linear relationship between UV/W and the risk of CSVD. At follow-up, lacunae and WMH were associated with cognitive decline, CMB and lacunae were associated with all-cause mortality. CONCLUSIONS: UV/W was associated with the risk of CSVD in hemodialysis. Reducing UV/W might protect hemodialysis patients from CSVD and subsequent cognitive decline and mortality.