Background: Plasma endothelin (ET) is elevated in end-stage renal disease (ESRD), but the origin and consequences of this increase remain unclear. In the present study we analysed the relationships between plasma ET levels and cardiovascular alterations in ESRD.
Methods and results: Common carotid artery (CCA) intima-media thickness (IMT) and diameter, atherosclerotic plaque occurrence, and left ventricular (LV) geometry and function were determined by ultrasound imaging in 76 haemodialysis patients and in 57 age-, sex-, and blood pressure-matched controls. Arterial stiffness was evaluated via carotid-femoral pulse wave velocity (CF-PWV), forearm post-ischaemic vasodilation was measured by venous plethysmography, and plasma ET levels were determined using a specific immunoenzymoassay. Compared with controls, ESRD patients had elevated plasma ET levels (1.6 +/- 1.4 vs 4.6 +/- 3.8 pg/ml; P < 0.001), increased LV mass (P < 0.001), increased CCA-IMT (P < 0.001), a higher prevalence of atherosclerotic plaques (P < 0.001) and increased CF-PWV (P < 0.01). Plasma ET levels correlated positively with LV outflow velocity integral (r = 0.57; P < 0.0001), stroke index (P < 0.01), and baseline forearm blood flow (P < 0.001) which were all significantly higher in ESRD patients than in controls (P < 0.01). After adjustment for age, blood pressure, haemoglobin levels, gender and body dimensions, plasma ET levels were significantly correlated to LV mass (r = 0.46; P < 0.001), CCA-IMT and CCA intima-media cross-sectional area (r = 0.41; P < 0.001), and CF-PWV (P < 0.05). Post-ischaemic forearm vasodilation was decreased in ESRD (85 +/- 31 vs 119 +/- 28%; P < 0.001) and there was a negative correlation between post-ischaemic flow recovery and ET levels (r = -0.49; P < 0.001). In ESRD patients, plasma ET levels were positively and independently correlated with the prevalence of CCA atherosclerotic plaque (P < 0.01).
Conclusions: These results indicate that the increased plasma ET levels in ESRD patients are associated with left ventricular hypertrophy and arterial intima-media thickening, suggesting that increased ET concentrations in ESRD patients may be of pathophysiological significance in the process of cardiovascular remodelling.