改良阻力指数判断移植肾舒张期反向血流患者预后的价值

目的 探讨改良阻力指数(RI)判断移植肾舒张期反向血流患者预后的价值.方法 出现移植肾舒张期反向血流者共24例,按其保肾是否成功分为手术组(5例)和非手术组(19例),对其改良RI值进行分析比较.改良RI的定义为收缩期峰值流速与舒张期峰值流速之和与收缩期峰值流速之比.用受试者工作特征(ROC)曲线评价改良RI判断移植肾预后的准确性.结果 非手术组改良RI为1.22±0.08,低于手术组的1.57±0.26,差异有统计学意义(P＜0.05).ROC曲线评估改良RI判断移植肾保肾是否成功的曲线下面积为0.979,正确指数最大(90%)时,改良RI判断移植肾保肾是否成功的最佳界值为1.31,其敏感性为100%,特异性为90%,阳性预测值为71%,阴性预测值为100%,准确性为92%.改良RI界值为1.31时,判断舒张期反向血流患者肾功能恢复正常的最低准确性为83%(20/24),最高准确性为92%(22/24).结论 对于移植肾出现舒张期反向血流的患者,改良RI是判断移植肾预后的一个无创、有价值的指标.

Improved resistance index in renal allograft with reversed diastolic flow

Objective To study the accuracy of improved resistance index (RI) in judging the prognosis in renal allograft with reversed diastolic flow. Methods According to the transplant nephrectomy, patients with reversed diastolic flow in renal allograft were classified into two groups:surgical group (n = 5) and nonsurgical group (n = 19). The differences in improved RI between two groups were compared by using Student's t test. Improved RI was defined as a ratio of peak systolic velocity plus peak diastolic velocity divided by peak systolic velocity. Receiver operating characteristic (ROC) curve was constructed for improved RI to evaluate diagnostic accuracy in judging the prognosis in renal allograft with reversed diastolic flow. Results Improved RI in surgical group ( 1.57 ± 0. 26)was higher than in nonsurgical group (1.22 ± 0. 08) (P＜＜0. 05). Areas under ROC curve for improved RI was 0. 979. An improved RI threshold of 1.31 had 100 % sensitivity, 90 % specificity, 71%positive predictive value, and 100 % negative predictive value for renal allograft with reversed diastolic flow loss as the maximum Youden index was 90 %. Applying this cutoff value to predict the function of renal allograft with reversed diastolic flow recovery, the accuracy was 92 % (maximum) or 83 %(minimum). Conclusion Improved RI can not only serve as a useful noninvasive index to predict renal allograft with reversed diastolic flow loss, but also to predict the function of renal allograft with reversed diastolic flow recovery.