BACKGROUND - The leading cause of death in end stage renal disease is cardiovascular disease (CVD). Kidney transplantation is associated with improved survival over dialysis. We hypothesized that arterial stiffness, a marker of CVD, would improve in patients post kidney transplant, potentially explaining one mechanism of survival benefit from transplant.
METHODS - After obtaining Institutional Review Board approval and informed consent, we performed a longitudinal prospective cohort study of 66 newly transplanted adult kidney transplant recipients, using aortic pulse wave velocity (PWV) to assess arterial stiffness over a 12 month period. All patients were assessed within one month of transplant (baseline) and 12 months post transplant. The primary outcome was change in PWV score at 12 months which we assessed using Wilcoxon Signed Rank test. Secondary analyses included correlation of predictors with PWV score at both time points.
RESULTS - The median age of the cohort was 49.7 years at transplant, with 27 % Black and 27 % female. At baseline, 43 % had tobacco use, 30 % had a history of CVD, and 42 % had diabetes. Median baseline calcium was 9.1 mg/dL and median phosphorus was 5.1 mg/dL. Median PWV score was 9.25 and 8.97 m/s at baseline versus month 12, respectively, showing no significant change (median change of -0.07, p = 0.7). In multivariable regression, subjects with increased age at transplant (p = 0.008), diabetes (p = 0.002), and a higher baseline PWV score (p < 0.001) were at increased risk of having a high PWV score 12 months post transplant.
CONCLUSION - Aortic arterial stiffness does not progress in the first year post kidney transplant. Increasing age, diabetes, and higher baseline PWV score identify patients at risk for increased arterial stiffness. Further research that assesses patients for greater than one year and includes a control dialysis group would be helpful in further understanding the change in arterial stiffness post transplantation.