Kidney transplantation improves endothelium-dependent vasodilation in patients with endstage renal disease.

Kidney transplantation (Tx) improves the cardiovascular outcome of patients receiving hemodialysis (HD). Therefore, we asked whether Tx improves the endothelial dysfunction of HD patients. Eight patients were studied twice: (1) during HD and (2) after Tx. We also studied eight matched control subjects. We measured forearm blood flow by venous occlusion plethysmography. We administered intrabrachial infusions of three doses of norepinephrine, glycerol trinitrate, acetylcholine (ACH), and N-monomethyl-L-arginine. The response to ACH was reduced in HD patients compared with controls (P<0.001). The response to ACH in HD patients improved after Tx, and this change was significant for low-dose ACH (P<0.05 for dose one and two compared with HD). The response to glycerol trinitrate, which was reduced in HD patients compared with controls (P<0.01), remained unchanged after Tx. N-monomethyl-L-arginine and norepinephrine comparably reduced forearm blood flow in all groups. This is the first evidence showing an improvement of endothelial dysfunction in HD patients after Tx.