Serial resistive index and pulsatility index for diagnosing renal complications in the early posttransplant phase: improving diagnostic efficacy by considering maximum values.

OBJECTIVES: To present new approaches to using duplex Doppler scanning to detect kidney complications in the early posttransplant period. MATERIALS AND METHODS: We assessed the resistive index and the pulsatility index in 127 renal transplant patients (73 men, mean age, 35.2 +/- 14 years) who underwent duplex Doppler scanning on the first, third, and fifth days after transplant. Biopsies were performed in patients suspected of having graft dysfunction owing to clinical and laboratory findings. To differentiate complicated from healthy grafts, a receiver operating characteristic curve analysis was done, and an area under the curve was calculated for each variable. RESULTS: In total, 47 grafts (37%) became complicated (40 rejections). The mean resistive index and mean pulsatility indexwere statistically significantly higher on the first, third, and fifth days after transplant in patients with complicated grafts than they were in patients with noncomplicated grafts (P < .0001). The mean resistive index and mean pulsatility index showed a significant rise from the first to the fifth day in patients with complicated grafts (P = .014). The area under the curve of the receiver operating characteristic curve for resistive index and pulsatility index on successive days was statistically significant (P < .0001). The resistive index and the pulsatility index area under the curve were statistically significantly lower on the first day than they were on subsequent days. Considering the maximum value of a serially measured resistive index and pulsatility index (which were determined by comparing 3 measurements on the fifth day and selecting the highest one) as a new variable showed a better area under the curve compared with that calculated on the third day (P = .05 for resistive index; P = .012 for pulsatility index). CONCLUSIONS: The resistive index and the pulsatility index are effective means of diagnosing posttransplant renal complications. Including a serial assessment and considering the maximum values could improve the diagnostic efficacy on the fifth day after transplant.