Department of Nephrology, Illawarra Shoalhaven Local Health District, Wollongong, New South Wales, Australia.
Department of Ultrasonography and Doppler Imaging, Vascular Care Centre, Wollongong, New South Wales, Australia.
Intern Med J. 2022 Oct;52(10):1773-1779. doi: 10.1111/imj.15542. Epub 2022 Aug 1.
Renal resistive index (RRI), which reflects intrarenal arterial impedance, is routinely measured when undertaking renal Doppler ultrasonography (RDU). Increased RRI has been suggested to reflect renal parenchymal disease and imply risk of kidney disease progression. But this has been disputed and extra-renal haemodynamic factors rather than intra-renal factors have been proposed to determine RRI.
To investigate the relationship between elevated RRI and presence of chronic kidney disease (CKD), and examine whether elevated RRI at baseline is associated with decline in estimated glomerular filtration rate (eGFR) on follow up.
This retrospective observational study examined the association of elevated RRI (>0.7) with the presence of CKD (eGFR < 60 mL/min for >3 months), demographic and clinical factors in multivariable models. We also examined the effect of elevated RRI on eGFR decline on follow up using mixed models.
Of the 346 patients undergoing RDU (median age 69.7 years; 46.2% male), 180 had elevated RRI. There was a strong inverse association between RRI and eGFR at baseline, 1 and 2 years (rho = -0.53, -0.51, -0.53, all P < 001). Elevated RRI was independently predicted by older age (odds ratio 3.29; 95% confidence interval 2.25-4.8; P < 0.001) and diabetes (odds ratio 2.65; 95% confidence interval 1.21-5.80; P = 0.015), but not CKD using multivariate logistic regression. Decline of eGFR was not different between RRI categories on follow up.
Elevated RRI was predicted by older age and diabetes, but not by the presence of CKD. Baseline RRI was not associated with eGFR decline.
肾阻力指数（RRI）反映了肾内动脉阻抗，在进行肾多普勒超声检查（RDU）时常规测量。升高的 RRI 被认为反映了肾实质疾病，并暗示了肾脏疾病进展的风险。但这一点存在争议，有人提出，肾外血液动力学因素而非肾内因素决定了 RRI。
研究升高的 RRI 与慢性肾脏病（CKD）的关系，并检查基线时升高的 RRI 是否与随访时估算肾小球滤过率（eGFR）的下降有关。
本回顾性观察性研究在多变量模型中检查了升高的 RRI（>0.7）与 CKD（eGFR <60 mL/min 持续>3 个月）、人口统计学和临床因素的关系。我们还使用混合模型检查了升高的 RRI 对随访时 eGFR 下降的影响。
在 346 例行 RDU 的患者中（中位年龄 69.7 岁；46.2%为男性），180 例患者的 RRI 升高。RRI 与基线、1 年和 2 年时的 eGFR 呈强负相关（rho=-0.53、-0.51、-0.53，均 P<0.001）。高龄（比值比 3.29；95%置信区间 2.25-4.8；P<0.001）和糖尿病（比值比 2.65；95%置信区间 1.21-5.80；P=0.015）是升高 RRI 的独立预测因素，但不是多变量逻辑回归中的 CKD。在随访期间，RRI 类别之间的 eGFR 下降无差异。
升高的 RRI 由年龄增长和糖尿病预测，但不由 CKD 预测。基线 RRI 与 eGFR 下降无关。
