[Thesis defence] 8/12/23, Matthieu Josse: "Exercise during dialysis: a cardioprotective role" (LAPEC)

Title of the thesis

Exercise during dialysis: a cardioprotective role?

Date and place

Agroscience amphitheatre, Jean-Henri Fabre campus
08 December 2023 - 1pm

Discipline

Sciences and techniques of physical and sports activities

Laboratory

Experimental Cardiovascular Physiology Laboratory (UPR-4278)

Framing

• Director: Obert Philippe
• Co-director: Maufrais Claire

Composition of the jury

• M. CANAUD Bernard, PU Emeritus, University of Montpellier - Rapporteur
• M. SCHNELL Frédéric, PU-PH, CHU Pontchaillou, Rennes - Rapporteur
• Mr CRISTOL Jean-Paul, PU-PH, CHU Montpellier - Examiner
• Mr LEPRÊTRE Pierre-Marie, PU, University of Rouen - Examiner
• Mr NOTTIN Stéphane, PU, Avignon University - Examiner
• Mr FLORENS Nans, PH, CHU Strasbourg - Guest

Summary of the thesis

Patients with end-stage renal disease (ESRD) have a risk of death from cardiovascular causes that is 10 to 30 times higher than in the healthy population. Haemodialysis, which is essential for their survival, induces abnormalities in left ventricular segmental contraction, which may be transient but which, repeated over the course of dialysis, contribute in the long term to deleterious morpho-functional remodelling and an increased risk of major cardiac events and cardiovascular mortality. Physical exercise has been proposed as an interesting countermeasure, in particular to limit haemodynamic instability, a key factor in the aetiology of dialysis-induced myocardial siderosis. However, very few studies are available on its effects on the heart, and the mechanisms underlying any cardioprotection are still largely unexplained. This thesis is based on a comprehensive, regionalised assessment of regional myocardial function using echocardiography in deformation imaging mode during dialysis. The first part of the thesis focused on the effects of acute exercise. An initial study clarified the effects of intradialytic exercise on left ventricular parietal biomechanics. A second study confirmed the reduction in the number of segmental contraction anomalies previously reported in preliminary exploratory studies and established that the benefits of intradialytic exercise were mainly obtained in the apical region. A third study demonstrated similar cardioprotection under intra- and pre-dialytic exercise conditions, ruling out the involvement of haemodynamic factors in the mechanisms underlying exercise-induced cardioprotection. Our results suggested a role for cardiac preconditioning by exercise and reinforced the idea that exercise contributes to the preservation of myocardial perfusion at the level of the microcirculation, as shown by the assessment of blood viscosity. The final study in this series highlighted the benefits of several weeks' intradialytic rehabilitation on regional myocardial function following dialysis and on cardiac remodelling, which may promote tissue perfusion. Taken together, these studies are of significant clinical importance and argue in favour of considering physical exercise as an integral part of the therapeutic management of haemodialysis patients.