Schäberle W, Leyerer L, Schierling W, Pfister K
Department of Visceral, Vascular, Thorax and Pediatric Surgery, "Klinik am Eichert", Eichertstr. 3, 73035 Göppingen, Germany.
Vascular and Endovascular Surgery, Regensburg University Hospital, Regensburg, Germany.
Gefasschirurgie. 2016;21:4-13. doi: 10.1007/s00772-015-0060-3. Epub 2015 Aug 28.
As a non-invasive, side effect-free and cost-effective method, ultrasonography represents the method of choice for the diagnosis of renal artery stenosis. Four different criteria in total, including two direct criteria in peak systolic velocity (PSV) and renal aortic ratio (RAR) and two indirect criteria in resistance index (RI) and acceleration time (AT) for the measurement of relevant renal artery stenosis are described, each demonstrating highly variable accuracy in studies. Furthermore, there is controversy over the degree beyond which stenosis becomes therapeutically relevant and which ultrasound PSV is diagnostically relevant in terms of stenosis grading.
This article gives a critical review based on a selective literature search on measurement methodology and the validity of ultrasound in renal artery stenosis. A critical evaluation of methods and a presentation of measurement principles to establish the most precise measurement method possible compared with the gold standard angiography, as well as an evaluation of the importance of computed tomography angiography (CTA) and magnetic resonance angiography (MRA).
The PSV provides high sensitivity and specificity as a direct measurement method in stenosis detection and grading. Most studies found sensitivities and specificities of 85-90 % for > 50 % stenosis at a PSV > 180-200 cm/s in ROC curve analysis. Other methods, such as the ratio of the PSV in the aorta to the PSV in the renal artery (RAR) or indirect criteria, such as side to side differences in RI (dRI) or AT can be additionally used to improve accuracy. Contrast-enhanced ultrasound improves accuracy by means of echo contrast enhancement. Although in the past only high-grade stenosis was considered relevant for treatment, a drop in pressure of > 20 mmHg in > 50 % stenosis (PSV 180 cm/s) is classified as relevant for increased renin secretion. Stenosis in fibromuscular dysplasia can be reliably graded according to the continuity equation. Although the available studies on the grading of in-stent restenosis are the subject of controversy, there is a tendency to assume higher cut-off values for PSV and RAR. Whilst MRA and CTA demonstrate an accuracy of > 90 %, this is at the cost of possible side effects for patients, particularly in the case of pre-existing renal parenchymal damage.
This article includes two additional video sequences on visualizing renal artery stenosis. This supplemental material can be found under: dx.doi.org/10.1007/s00772-015-0060-3.
超声检查作为一种无创、无副作用且经济高效的方法，是诊断肾动脉狭窄的首选方法。总共描述了四种不同的标准，包括收缩期峰值流速（PSV）和肾主动脉比率（RAR）这两个直接标准，以及阻力指数（RI）和加速时间（AT）这两个间接标准，用于测量相关的肾动脉狭窄，每项标准在研究中的准确性都有很大差异。此外，对于狭窄在何种程度上具有治疗相关性以及在狭窄分级方面何种超声PSV具有诊断相关性存在争议。
本文基于对肾动脉狭窄测量方法及超声有效性的选择性文献检索进行批判性综述。对方法进行批判性评估，并介绍测量原理，以建立与金标准血管造影相比尽可能精确的测量方法，同时评估计算机断层血管造影（CTA）和磁共振血管造影（MRA）的重要性。
PSV作为狭窄检测和分级的直接测量方法具有高灵敏度和特异性。大多数研究在ROC曲线分析中发现，对于PSV＞180 - 200 cm/s时＞50%的狭窄，灵敏度和特异性为85 - 90%。其他方法，如主动脉PSV与肾动脉PSV的比率（RAR）或间接标准，如RI的左右差异（dRI）或AT，可额外用于提高准确性。超声造影通过增强回声对比提高准确性。尽管过去仅认为高度狭窄与治疗相关，但对于＞50%狭窄（PSV 180 cm/s）时压力下降＞20 mmHg，归类为与肾素分泌增加相关。纤维肌发育不良中的狭窄可根据连续性方程可靠分级。尽管关于支架内再狭窄分级的现有研究存在争议，但倾向于采用更高的PSV和RAR截断值。虽然MRA和CTA的准确性＞90%，但这是以患者可能出现副作用为代价的，尤其是在已有肾实质损害的情况下。
本文包括两段关于可视化肾动脉狭窄的附加视频序列。该补充材料可在以下网址找到：dx.doi.org/10.1007/s00772-015-0060-3。
