Division of Vascular Surgery, Department of Surgery and Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Ore.
Division of Vascular Surgery, Department of Surgery and Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Ore.
J Vasc Surg. 2020 Sep;72(3):951-957. doi: 10.1016/j.jvs.2019.10.099. Epub 2020 Jan 19.
The external carotid artery (ECA) serves as a major collateral pathway for ophthalmic and cerebral artery blood supply. It is routinely examined as part of carotid duplex ultrasound, but criteria for determining ECA stenosis are poorly characterized and typically extrapolated from internal carotid artery data. This is despite the fact that the ECA is smaller in diameter, with a higher resistance and lower volume flow pattern. We hypothesized that using the cutoff of a peak systolic velocity (PSV) ≥125 cm/s, extrapolated from internal carotid artery data, will overestimate the prevalence of ≥50% ECA stenosis and aimed to determine a more appropriate criterion.
From December 2016 to July 2017, consecutive carotid duplex ultrasound studies performed in our university hospital Intersocietal Accreditation Commission-accredited vascular laboratory were prospectively identified and categorized with respect to prevalence and distribution of ECA PSVs and color aliasing, an indication of turbulent flow or flow acceleration. Presence of color aliasing was determined by two individual reviewers and agreement assessed by Cohen κ coefficient. ECA stenosis was calculated by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method in patients with computed tomography angiography (CTA) performed within 3 months of carotid duplex ultrasound without an intervening intervention. Receiver operating characteristic analysis was performed to identify best criteria for determining ≥50% ECA stenosis.
There were 1324 ECAs from 662 patients analyzed; 174 patients had a total of 252 ECAs with PSV ≥125 cm/s (19% of the total sample). Of those ECAs with PSVs ≥125 cm/s, 30.5% were between 125 and 149 cm/s, 22.2% were between 150 and 174 cm/s, 13.1% were between 175 and 199 cm/s, and 34.1% were ≥200 cm/s. There were 341 ECAs that were analyzed for the presence of color aliasing. In 86 ECAs with PSV ≥200 cm/s, 58.1% had color aliasing, whereas in 255 ECAs with PSV <200 cm/s, only 19.2% had color aliasing (P = .0001). There were 325 CTA studies reviewed and assessed for the presence of a ≥50% ECA stenosis as determined by CTA. Overall, the combination of an ECA PSV ≥200 cm/s with the presence of color aliasing provided the highest combination of sensitivity (90%), specificity (96%), positive predictive value (83%), and negative predictive value (98%) and the greatest area under the curve of 0.971 for determining the presence of a ≥50% ECA stenosis based on CTA.
A PSV ≥125 cm/s alone probably overestimates the prevalence of ≥50% ECA stenosis. A PSV ≥200 cm/s combined with color aliasing is highly predictive of >50% ECA stenosis based on correlation with CTA.
颈外动脉（ECA）是眼动脉和脑动脉血液供应的主要侧支通路。它通常作为颈动脉双功超声检查的一部分进行检查，但确定 ECA 狭窄的标准描述得很差，通常是从颈内动脉数据推断出来的。尽管 ECA 的直径较小，阻力较高，血流模式较低，但事实就是如此。我们假设使用从颈内动脉数据推断出的收缩期峰值速度（PSV）≥125cm/s 的截止值将高估≥50% ECA 狭窄的患病率，并旨在确定更合适的标准。
从 2016 年 12 月至 2017 年 7 月，在我们大学医院经互认委员会认证的血管实验室进行的连续颈动脉双功超声检查研究被前瞻性地确定，并根据 ECA PSV 和彩色伪影的分布进行分类，彩色伪影表明存在湍流或血流加速。两名独立的审查员确定彩色伪影的存在，并通过 Cohen κ 系数评估一致性。在颈动脉双功超声检查后 3 个月内进行计算机断层血管造影（CTA）的患者中，按照北美症状性颈动脉内膜切除术试验（NASCET）方法计算 ECA 狭窄程度，在颈动脉双功超声检查期间未进行干预。进行受试者工作特征分析以确定确定≥50% ECA 狭窄的最佳标准。
对 662 名患者的 1324 个 ECA 进行了分析；174 名患者共有 252 个 ECA 的 PSV≥125cm/s（总样本的 19%）。在 PSV≥125cm/s 的 ECA 中，30.5%的 PSV 在 125 至 149cm/s 之间，22.2%的 PSV 在 150 至 174cm/s 之间，13.1%的 PSV 在 175 至 199cm/s 之间，34.1%的 PSV≥200cm/s。对 341 个 ECA 进行了彩色伪影的存在分析。在 PSV≥200cm/s 的 86 个 ECA 中，58.1%存在彩色伪影，而在 PSV＜200cm/s 的 255 个 ECA 中，只有 19.2%存在彩色伪影（P=0.0001）。回顾了 325 项 CTA 研究，并根据 CTA 评估是否存在≥50%的 ECA 狭窄。总体而言，ECA PSV≥200cm/s 与彩色伪影的存在相结合，在确定≥50%ECA 狭窄的存在方面提供了最高的敏感性（90%）、特异性（96%）、阳性预测值（83%）和阴性预测值（98%），并根据 CTA 获得了 0.971 的最大曲线下面积。
单独使用 PSV≥125cm/s 可能高估了≥50%ECA 狭窄的患病率。PSV≥200cm/s 结合彩色伪影高度提示根据 CTA 存在≥50%的 ECA 狭窄。
