Arterial function after successful renal transplantation

Background. Renal transplantation is increasingly the preferred method of renal replacement therapy. Cardiovascular disease is the major barrier to long-term survival for transplant recipients. The aim of this study was to determine whether the increased arterial stiffness of patients with chronic renal failure is improved after successful renal transplantation. Methods. The study involved a group of 36 patients, aged 27 to 68 years (mean +/- SD 46 +/- 11 years) who had cardiovascular risk assessment and measurements of carotid artery intima-media thickness (IMT), arterial pulse wave velocity [aorto-femoral (PWV a-f) and femoral-dorsalis pedis (PWV f-d)], systemic arterial compliance (SAC), and arterial wave reflection (augmentation index, AI(x)) performed before and 12 months after successful renal transplantation. B-mode ultrasound measurements were used to determine mean carotid IMT and applanation tonometry techniques to determine SAC, AI(x), PWV (a-f), PWV (f-d), and central pressures. On each occasion the following were also measured: fasting lipids, homocysteine (tHcy), red cell folate, cobalamin, and fibrinogen levels. Results. One year after transplantation, mean serum creatinine was 143 +/- 47 mumol/L, and creatinine clearance 60 +/- 16 mL/min/1.74m(2) (range 25 to 104 mL/min/1.74m(2)). Total and low-density lipoprotein (LDL) cholesterol were significantly reduced. tHcy was decreased by 38% and normalized in 45%. Systolic and diastolic blood pressure and mean arterial pressure were all improved. From baseline to 12 months' post-transplantation. there was no significant change in carotid IMT (mean IMT 0.76 +/- 0.11 vs. 0.75 +/- 0.14 mm, P = 0.28) or SAC (0.45 +/- 0.23 vs. 0.46 +/- 0.22 units, P = 0.95), but PWV [PWV (a-f) 9.6 +/- 2.6 vs. 8.8 +/- 2.2 m/sec, P = 0.007; PWV (f-d) 10.7 +/- 1.8 vs. 8.4 +/- 1.7 m/sec, P < 0.001] and AI(x) (24.3 ± 13.4 vs. 15.9 ± 11.4%. P = 0.003) improved. After adjusting for the differences in blood pressure, the changes in PWV (a-f) were no longer significant, but the differences in PWV (f-d) persisted. The change in AI(x) remained significant after adjusting, for differences in heart rate, and the fall in AI(x) was greater in patients on immunosuppression with tacrolimus compared with those on cyclosporine. Conclusion. One year after successful renal transplantation, improvement in cardiovascular risk factors was associated with improvement in indices of arterial stiffness.