Endothelium-dependent Vasodilatation and Distensibility of Large Arteries in Chronic Haemodialysis Patients

Background: Cardiovascular mortality is increased in chronic haemodialysis (HD) patients and is not completely explained by common cardiovascular risk factors. Hyperhomocysteinaemia and chronic HD per se may play a role, because these factors may adversely affect endothelial function and distensibility of conduit arteries, which are important determinants of the risk of atherosclerosis, thrombosis and cardiac hypertrophy.

Methods: A vessel wall movement detector system was used to investigate endothelium-dependent, flow-mediated and endothelium-independent, glyceryl trinitrate-induced vasodilatation in the brachial artery and compliance and distensibility coefficients (CC and DC) in the common carotid artery in 28 chronic HD patients and 28 control subjects.

Results: Endothelium-dependent, but not endothelium-independent, vasodilatation was markedly reduced in the HD group (3.7 +/- 1.1 vs. 9.7 +/- 1.2%; P = 0.001). The DC was reduced only in a subgroup of patients aged < 50 years: 16.9 +/- 1.5 vs. 22.4 +/- 2.0 10(-3)/kPa (P = 0.032) and was not related to endothelium-dependent vasodilatation. CC did not differ between the groups. Plasma total homocysteine was elevated in the HD patients, but was neither related to endothelium-dependent vasodilatation, nor to DC.

Conclusion: Chronic renal failure and (or) chronic haemodialysis are associated with impaired endothelium-dependent vasodilatation, which may reflect an increased susceptibility for the development of atherosclerosis and thrombosis.