Acute effects of haemodialysis on endothelial function and large artery elasticity

Background. Disturbances of functional properties of large arteries contrib ute to increased cardiovascular morbidity and mortality in patients with en d-stage renal disease. However, it is not clear whether haemodialysis per s e acutely affects mechanical vessel wall properties or endothelial function . Methods. Twenty-five chronic haemodialysis patients (mean +/- standard erro r 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 (ultrafil tration 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 wer e measured by Doppler frequency analysis of vessel wall movements in M-mode using a multigate pulsed Doppler system and aortic pulse wave velocity (PW V) by an automatic device (Complior(R)). Endothelial function was determine d as brachial artery flow-mediated dilation (FMD) and compared with endothe lium-independent nitroglycerine-induced dilation (NMD). Results. FMD was 7.9 +/- 1.8% in patients before HD and did not change sign ificantly 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 duri ng HD (from 18.1 + 1.9 x 10(-3)/kPa to 16.7 +/- 2.2 x 10(-3)/kPa, P<0.05) a nd 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 distensib ility 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 endo thelial function or large artery mechanical vessel wall properties in patie nts on maintenance dialysis therapy.