Uremic Toxins, Cardiovascular Effects and Physical Activity in Intensive Hemodialysis

End-stage renal disease (ESRD) patients on dialysis have high annual mortality
rates. Kidney transplantation is the gold standard renal replacement therapy.
However, the demand for kidney transplantation exceeds the supply of organs.
Intensive hemodialysis is associated with significant improvement of
biochemical, biological and clinical parameters. This may be due to increased
clearance of uremic toxins and optimized volume control leading to improved
vascular biology and reduced cardiovascular disease. Furthermore, intensive
hemodialysis patients may have better physical activity scores and quality of
life which may further reduce morbidity and mortality in these patients.

The primary objective of this study is to compare vascular biology (vascular
markers and endothelial microparticles) and cardiovascular effects (volume
status, blood pressure, pulse wave velocity and microcirculation) in
conventional hemodialysis (CHD), intensive HD [Short Daily Hemodialysis (SDHD),
nocturnal hemodialysis (NHD) (3 nights per week) and home NHD (HNHD) (5 to 6
nights per week)] and peritoneal dialysis (PD) patients. The secondary
objectives of this study are to compare the kinetics and levels of uremic
toxins as well as the degree of physical activity in patients treated with
these different dialysis modalities.

Incident and prevalent CHD, intensive HD [SDHD, NHD and HNHD] and peritoneal
dialysis (PD) patients will be prospectively followed up in an observational
study over a period of 2 years. All patients will be included in the study over
a period of 2 years. Every 6 months, vascular parameters will be meausred in
blood samples. Also, body composition (with BCM), pulse wave velocity (with
Sphygmocor), echocardiography (evaluation of left ventricular hypertrophy and
fluid status), microcirculation (with capillaroscopy), 24-hour blood pressure
(with Mobil-O-Graph) and physical activity (with Sensewear) will be measured.
Also, patients will be requested to fill out a quality of life questionnaire at
the time of each visit. Last, predialytic and postdialytic levels of several
uremic toxins will be measured during a mid-week dialysis session.

In this study, only non-invasive techniques which pose a minimal burden to the
patient will be used. Blood sampling will coincide with the dialysis sessions.
The study will not have direct benefit for the participants. The study can only
be performed with this specific patient group.