Early Assessment of Renal Resistance Index and Long-Term Renal Function in Renal Transplant Recipients

Abstract

Background. The effect of the intrarenal arterial resistance index (RI) on long-term renal functions is not well known. We examined the predictive value of intrarenal RI on long-term allograft outcomes. Methods. We retrospectively investigated 121 stable renal transplant recipients, followed for a mean of 63.21 ± 19.9 months after renal transplant. Patients with complications during the first six months after transplant were not included. Color Doppler ultrasonography was done to calculate the intrarenal RI within the first four weeks after transplant. Results. Older recipient age, high pulse pressure, active smoking, and proteinuria were associated with a higher intrarenal RI. Multivariate analyses revealed that renal RI and donor age were independent predictors of allograft outcome. Kaplan-Meier estimates of cumulative graft survival were significantly worse in patients who had an RI of 0.7 or more than they were in patients who had an RI of less than 0.7 (p = .005). Development of chronic allograft nephropathy (CAN) was significantly higher in patients who had an RI of 0.7 or more (p = .02). Conclusions. Renal RI determined within the first month after renal transplant predicts long-term allograft function and development of CAN in renal transplant recipients.