Acute effects of haemodialysis on endothelial function and large artery elasticity

Background. Disturbances of functional properties of large arteries contribute to increased cardiovascular morbidity and mortality in patients with end-stage renal disease. However, it is not clear whether haemodialysis per se acutely affects mechanical vessel wall properties or endothelial function. Methods. Twenty-five chronic haemodialysis patients (mean +/- standard error of the mean (SEM): age 52 +/- 5 years; time on dialysis 63 +/- 7 months; blood pressure 132 +/- 4/72 +/- 2 mmHg) were studied before and immediately after a haemodialysis (HD) session using a polysulphone dialyser (ultrafiltration 1460 +/- 54mi), as well as on the following day. Blood pressure was measured with an automatic sphygmomanometer and applanation tonometry. End-diastolic diameter and distension of the brachial and carotid arteries were measured by Doppler frequency analysis of vessel wall movements in M-mode using a multigate pulsed Doppler system and aortic pulse wave velocity (PWV) by an automatic device (Complior(R)). Endothelial function was determined as brachial artery flow-mediated dilation (FMD) and compared with endothelium-independent nitroglycerine-induced dilation (NMD). Results. FMD was 7.9 +/- 1.8% in patients before HD and did not change significantly after HE, or in the dialysis-free intervall (6.7 +/- 2.1 and 7.1 +/- 2.0%, respectively; NS). The same was true for NMD and PWV (12.6 +/- 0.8 m/s before HD, 12.8 +/- 0.8 m/s after HD, and 11.9 +/- 0.7 m/s on the HD-free day). Carotid distensibility coefficients decreased significantly during HD (from 18.1 + 1.9 x 10(-3)/kPa to 16.7 +/- 2.2 x 10(-3)/kPa, P<0.05) and increased again on the HD-free day (19.8 +/- 2.4 x 10(-3)/kPa). However, when corrected for blood pressure by tonometry, isobaric carotid distensibility did not change significantly. Brachial artery distensibility also did not show significant acute changes. Conclusions. Haemodialysis per se did not have a significant effect on endothelial function or large artery mechanical vessel wall properties in patients on maintenance dialysis therapy.