Hypervolemia was associated with hypertension and endothelial dysfunction in kidney transplant recipients

Background: While the cardiovascular events decreases after renal transplantation compared with patients on dialysis, it nevertheless remains higher than in the general healthy population. The aim of the present cross-sectional study was to investigate association of hypervolemia with blood pressure, and endothelial functions in kidney transplant recipients. Methods: Eighty-two kidney transplant patients (52 male, 30 female, mean age: 51 ± 12.8 years) with stable allograft function were investigated. 59 patients (72%) were suffering from hypertension. The volume status of the patients was determined by using bioimpedance spectroscopy (BIS) as total body water (TBW), extracellular water (ECW), and intracellular water (ICW) and by measuring serum pro brain natriuretic peptide (pro BNP). Blood pressure (BP) was assessed by 24-h ambulatory blood pressure monitoring (ABPM). Endothelial function was measured by flow-mediated vasodilation. Echocardiographic examination was also performed. Results: Hypertensive patients had significantly higher TBW (36.3 ± 6.3 L vs 31.7 ± 6.1 L, p = 0.004), and ECW (17.1 ± 2.8 L vs 14.7 ± 3 L, p = 0.002). ECW was correlated with nighttime systolic BP in renal transplant recipients (r = 0.26, p = 0.04). However, there was no correlation between ECW with nighttime-daytime diastolic BP and daytime systolic BP in ABPM. There was a positive correlation between ECW with left atrial diameter, and left ventricular mass index (r = 0.57, p = 0.000; and r = 0.34, p = 0.006, respectively). A significant negative correlation was found between ECW and flow-mediated dilatation (r = −0.3, p = 0.007). Conclusion: Increased ECW was associated with hypertension, especially nighttime systolic BP, and endothelial dysfunction in renal transplant recipients. Hypervolemia might be a contributing factor in increased cardiovascular risk in kidney transplant recipients.