Age-related and blood pressure-independent reduction in aortic stiffness after kidney transplantation

OBJECTIVES: Aortic stiffness is a novel cardiovascular risk factor in patients with chronic kidney disease (CKD). The purpose of the present study is to examine whether there is a blood pressure-independent improvement in aortic stiffness 3 months after successful kidney transplantation (KTx), and whether this improvement is age-dependent. METHOD: In this prospective, longitudinal observational study, we studied hemodynamic and biological parameters prior to and 3 months after a KTx in 52 stage 5 CKD patients. Aortic stiffness was measured by carotido-femoral pulse wave velocity (c-f PWV) and enhanced central wave reflection was evaluated by the heart rate-adjusted central augmentation index (AIx) by means of arterial tonometry. Endothelin-1, L-arginine, asymmetric dimethylarginine (biomarkers of endothelial dysfunction), pentosidine (advanced glycation end-products) and mineral metabolism parameters were also measured. RESULTS: After adjusting for the reduction in mean blood pressure, c-f PWV decreased significantly from 12.1 ± 3.3 to 11.6 ± 2.3 m/s (P < 0.05). In an analysis stratified by age, this improvement was only present in patients older than 50 years of age as compared with patients younger than 50 years of age (-5.5 ± 2.2 vs. 2.1 ± 1.9%, P < 0.05). AIx decreased from 22 ± 11 to 14 ± 13% (P < 0.01), but this reduction was not age-dependent. We also observed a similar degree of improvement in the biomarker levels of endothelial dysfunction and pentosidine in both groups. CONCLUSION: This study shows for the first time that there is an age-dependent improvement in aortic stiffness after KTx. These observations suggest that older patients may have an added cardiovascular risk reduction after a successful KTx.