Department of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany.
Nephrol Dial Transplant. 2012 Oct;27(10):3958-63. doi: 10.1093/ndt/gfr772. Epub 2012 Jan 13.
The renal arterial resistance index (RI) is reported to be a significant predictive parameter for renal allograft failure or death. The influence of the time point after renal transplantation on its predictive power has not been sufficiently evaluated. We performed a retrospective analysis of RI and its power to predict renal allograft failure or death with special emphasis on the time point of RI measurement.
The present analysis is based on ultrasonographically recorded intrarenal arterial RI measurements, routinely obtained in our outpatient department, over a period of 13 years. Altogether, 88 patients with an RI measurement 0-3, 3-6 and 12-18 months after transplantation were included and retrospectively stratified into two groups according to the RI: those with an index >0.75 and those with an index of ≤0.75.
Twenty patients (23%) reached the combined end point, i.e. allograft failure with a return to dialysis or death. The RI measured early after transplantation (0-3 and 3-6 months) did not predict the end point, whereas the RI obtained between 12 and 18 months showed a significant predictive value for renal transplant failure or death in a univariate approach [Wald test, P = 0.0013, hazard ratio (HR) 4.787, 95% confidence interval (CI) 1.846-12.411]. At 12-18 months after transplantation, 14% (12 patients) of the study population had an RI >0.75. Seven (58%) of these patients reached the end point versus 13 of 76 patients (17%) with an RI ≤0.75. In a multivariate Cox model, the RI measured between 12 and 18 months after transplantation exhibited the highest hazard ratio (HR 6.191, 95% CI 2.288-16.756, P = 0.0003) for transplant failure or death.
In our hands, the RI obtained during the first 6 months after transplantation failed to predict renal allograft failure or death, whereas the RI measured 12-18 months after transplantation appeared useful to predict long-term allograft outcomes.
肾动脉阻力指数（RI）被报道为预测肾移植失败或死亡的重要预测参数。肾移植后时间点对其预测能力的影响尚未得到充分评估。我们对 RI 及其预测肾移植失败或死亡的能力进行了回顾性分析，特别强调 RI 测量的时间点。
本分析基于我们在门诊常规进行的肾内动脉 RI 测量的超声记录，时间跨度为 13 年。共有 88 例患者在移植后 0-3、3-6 和 12-18 个月进行了 RI 测量，根据 RI 将其分为两组：RI>0.75 组和 RI≤0.75 组。
20 例（23%）达到了联合终点，即移植肾失功并恢复透析或死亡。移植后早期（0-3 个月和 3-6 个月）测量的 RI 不能预测终点，而在 12-18 个月时测量的 RI 在单因素分析中对移植肾失败或死亡具有显著的预测价值[Wald 检验，P=0.0013，危险比（HR）4.787，95%置信区间（CI）1.846-12.411]。在移植后 12-18 个月时，研究人群中有 14%（12 例）的 RI>0.75。这 12 例患者中有 7 例（58%）达到终点，而 76 例 RI≤0.75 的患者中有 13 例（17%）达到终点。在多因素 Cox 模型中，在移植后 12-18 个月测量的 RI 显示出对移植失败或死亡的最高危险比（HR 6.191，95%CI 2.288-16.756，P=0.0003）。
在我们的研究中，移植后前 6 个月测量的 RI 不能预测肾移植失败或死亡，而移植后 12-18 个月测量的 RI 似乎可以预测长期移植结局。
