The Effect of Intradialytic Exercise Training on Cardiac and Arterial Health in Hemodialysis Patients

Abstract

INTRODUCTION AND AIMS: Patients with kidney failure undergoing chronic hemodialysis (HD) treatment have excessively high rates of cardiovascular (CV) morbidity and mortality. Exercise training as a part of a comprehensive treatment program has been shown to reduce the risk of CV events in patients with established CV disease. However, much less is known about the CV effects of exercise training in HD patients. The aim of this study was to determine the effect of 12 months of intradialytic exercise with concomitant protein supplementation on CV health in HD patients. METHODS: This is a secondary analysis of CV parameters measured from a subset of patients participating in the IHOPE trial (NCT#01234441). This analysis includes data from 98 HD patients (54±12 yrs; 59% male) randomized either to usual care (CON) or intradialytic exercise training + protein supplementation (EX) for 12 months. Patients in the EX group performed supervised moderate intensity exercise (RPE = 12-14) on cycle ergometers for 30-45 minutes with a concomitant oral protein supplement (30g whey) during treatment. Ultrasound exams were performed to measure cardiac systolic function (ejection fraction), diastolic function (early diastolic filling pressure; E, early diastolic tissue velocity; E’) and carotid arterial wall thickness (intima-media thickness, IMT). Outcomes were assessed at baseline, 6, and 12 months. RESULTS: There were no significant changes in any CV parameter between groups at 12-months (Group x Time interaction, p > 0.05 for all measures). However, there was a significant main effect of Time for EE’ in the overall study population, indicating a general worsening of left ventricular filling capacity at 12-months that was larger in CON compared to EX (p< 0.05). There was a similar trend for an increase in carotid IMT at 12-months in CON (p<0.05), that was not evident in EX. CONCLUSION: These data indicates that declines in cardiac diastolic function and increases in carotid IMT that manifest over time in HD patients may be attenuated by intradialytic exercise training. Surprisingly few studies have investigated the effects of exercise on CV structure and function in HD patients, thus, these findings warrant further investigation.