Chronic Intradialytic Exercise : a Cardioprotective Role

Background: Hemodialysis patients have a mortality rate 50 times higher than in the general population, and the cause remains cardiovascular in more than half of the cases. A deleterious morphological and functional cardiac remodelling is well established in these patients, the causes of which are both the presence of factors specific to renal disease (hemodynamic and non-hemodynamic) and co-morbidities (diabetes, hypertension, etc. .) but also to the hemodialysis (HD) procedure itself, due to the sudden hemodynamic changes it imposes, leading to repeated episodes of intradialytic hypotension (HID) and myocardial stunning. The latter are now documented as direct contributors to the increased mortality observed in HD patients compared to the general population. The introduction of intradialytic physical exercise in the therapeutic program of HD patient is now recommended and practised routinely in many countries, in Scandinavia in particular. Several meta-analyses have clearly established its safety. The beneficial role of chronic intradialytic exercise in improving dialysis efficiency, mental health and quality of life, as well as the inflammatory status of HD patients is also clearly demonstrated. Chronic intradialytic exercise is also associated with improvements in overall fitness level, a parameter closely linked to cardiovascular mortality. Applied acutely during dialysis, it could play a cardioprotective role (e.g; limiting myocardial stunning), allowing haemodynamic and cardiac functional stabilization during HD. However, to our knowledge, no study to date has investigated the long-term effects of intradialytic exercise on remodelling and overall and regional heart function. Aims: The main objective is to assess the effects of chronic intradialytic physical exercise on myocardial remodelling and regional function. The secondary objectives are to evaluate the effect of acute intradialytic exercise on myocardial stunning as well as the effect of chronic physical exercise on macro and microcirculatory vascular function, inflammation, physical fitness and health-related quality of life.