Effect of Intradialytic Exercise on Cardiovascular Outcomes in Maintenance Hemodialysis: A Systematic Review and Meta-Analysis.

BACKGROUND:Cardiovascular disease is the leading cause of death among people with kidney failure on hemodialysis, for whom improving cardiovascular health is a research priority. Intradialytic myocardial stunning is common and associated with adverse cardiovascular events. Intradialytic exercise may mitigate intradialytic myocardial stunning and improve cardiovascular structure and function. This systematic review investigated the effect of intradialytic exercise on cardiovascular outcomes in adults undergoing maintenance hemodialysis (PROSPERO #CRD42018103118). METHODS:Following PRISMA guidelines, we systematically searched MEDLINE, EMBASE, Cochrane CENTRAL, SportDiscus, and PEDro databases from 1960 until June 2022, for randomized and non-randomized studies investigating the effect of intradialytic exercise programs on objective cardiovascular outcomes, pre-specified as primary or secondary outcomes. The primary outcome was arterial resistance. RESULTS:Of 10837 references identified, 32 met eligibility criteria. These studies investigated the effect of intradialytic exercise on arterial resistance (8 studies), blood pressure (20 studies), myocardial structure and function (7 studies), endothelial function (2 studies), sympathetic overactivity (9 studies), biomarkers of cardiac injury (3 studies), cardiovascular hospitalization and mortality (2 studies). Most studies used aerobic exercise as the intervention and usual care (no exercise) controls. Meta-analysis of intradialytic exercise versus usual care resulted in a statistically significant reduction in arterial resistance measured by pulse wave velocity (PWV) with mean difference -1.63 m/sec (95% CI -2.51, -0.75). Meta-analyses for diastolic blood pressure, left ventricular ejection fraction (LVEF), and low-frequency/high-frequency (LF/HF ratio) measure of heart rate variability also showed statistically significant improvements with exercise. There was no significant difference in change in systolic blood pressure, augmentation index, and left ventricular mass index between groups. CONCLUSION:Intradialytic exercise programming resulted in a clinically meaningful improvement to PWV, a component of arterial resistance. Sseveral physiologic measures of cardiovascular health, including diastolic blood pressure, LVEF and heart rate variability measured by the LF/HF ratio were also observed. The effects of intradialytic exercise on major adverse cardiovascular events remains uncertain.