Nutritional status and intrarenal resistive indices after kidney transplantation

Obesity predicts vascular stiffness, which is prevalent among kidney transplant patients. However, the influence of obesity has not been established on parameters of renal vascular resistance variation. The aim of this study was to analyze the influence of nutritional status on intrarenal resistive parameters as measured in the early period after successful kidney transplantation by Doppler ultrasound.

Both pulsatility index (PI) and resistance index (RI) in the kidney graft were measured by Doppler sonography twice: at 2 to 4 days and before hospital discharge (mean 22 days; 95% confidence interval 21-23) after transplantation. Nutritional status was scored according to World Health Organization criteria.

Among 513 patients, 29 were underweight; 280, normal; 166, overweight; and 38, obese. Both PI and RI values were significantly increased consistent with recipient nutritional status (analysis of variance: P < .001). Post hoc analysis showed significant differences in PI and RI measurements for obese versus underweight or normal weight groups. Multivariate analysis revealed an influence of body mass index on PI and RI measurements before hospital discharge to be independent of other variables, including recipient age, prior delayed graft function and cold ischemia time.

Excessive nutritional status was associated with increased renal vascular resistance among kidney transplant patients. Nutritional status should be considered for the proper interpretation of intrarenal Doppler measurements.