Hemodiafiltration: cardiovascular parameters and convection volume

Abstract

End stage kidney disease patients have an extremely high risk cardiovascular morbidity and mortality. It has been hypothesized that hemodiafiltration, as opposed to the standard dialsysis modality hemodialysis, could diminish this cardiovascular risk due to superior removement of uremic toxins. The aims of this thesis were: (1) to study the relation between structural and functional cardiovascular markers and mortality / cardiovascular events in ESKD patients (2) to study determinants of change (including dialysis modality) in structural and functional cardiovascular markers of risk in ESKD patients and (3) to assess what determines convection volume and how convection volume changes over time. To research these aims, data was used from patients participating in the CONvective TRAnsport STudy (CONTRAST): a randomized controlled trial comparing hemodialysis and hemodiafiltration in terms of overall mortality and cardiovascular events. In this thesis we did not find determinants of cardiovascular markers in dialysis patients that could easily be modified in daily clinical practice (nor in terms of treatment guidelines nor in terms of dialysis modality). Thus future research should focus on prevention of reaching these abnormal values of cardiovascular surrogate markers in earlier stages of CKD. Another option would be to explore the effect of more intensified dialysis programs on these markers. A meta-analysis of three large RCTs showed that HDF patients seem to have a lower overall and cardiovascular mortality as compared to HD. A high convection volume is related to a lower mortality risk. In this thesis we show that treatment related dialysis characteristics and hospital specific aspects are more important in determining the magnitude of convection volume than intrinsic patient characteristics. Future studies should focus on whether it is feasible to achieve higher volumes in the majority of patients, and, if this is indeed the case, whether high prescribed convection volumes indeed lead to a better survival.