Early Sonographic Evaluation of Intrarenal Arterial Resistive Index and Long-term Renal Function in Renal Transplant Recipients in South Western Nigeria

BACKGROUND: Color Doppler ultrasonography of intrarenal arterial Resistive Index (RI), performed early after kidney transplant, has proven to reliably predict short-term allograft function. The aim of this study was to assess whether early Doppler assessment could correlate with long-term renal function. METHODS: This was a retrospective study of intrarenal RI using ultrasound in 41 stable kidney transplant patients who underwent RI assessment within 1 month after the transplant. Color Doppler ultrasonography was done to calculate the intrarenal RI within the first 4 weeks after transplant. The mean values of the intrarenal RI of the interlobar arteries of the allograft kidneys were measured and recorded. The data were analyzed with the aid of computer-based SPSS 20.0 software for windows (IBM, International Business Machines Corporation, Company, Armonk, New York, USA). RESULTS: Older recipient age, active smoking, and proteinuria were associated with a higher intrarenal RI. Multivariate analyses showed 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 the values of the RI of 0.7 or more than they were in patients who had the values of the RI of <0.7. CONCLUSION: This study reveals that renal RI determined within the 1(st) month after renal transplant correlates with long-term allograft function in kidney transplant recipients.