Eliasziw M, Smith R F, Singh N, Holdsworth D W, Fox A J, Barnett H J
Department of Epidemiology and Biostatics, University of Western Ontario, London, Canada.
Stroke. 1994 Dec;25(12):2445-9. doi: 10.1161/01.str.25.12.2445.
Three different methods for estimating the percentage of reduction in the diameter of the internal carotid artery (ie, stenosis) have been proposed in the literature. Further comparisons of the methods were carried out with the intent of recommending a current standard for determining the percentage of stenosis from angiograms.
Angiograms from 112 patients were obtained. For each angiogram, stenosis was estimated in the manner of the European Carotid Surgery Trial (ECST method), the North American Symptomatic Carotid Endarterectomy Trial (NASCET method), and by a method using the common carotid artery lumen diameter (CC method).
Although there is much discrepancy among the estimates of stenosis arising from the three different methods for any particular patient, it is possible to predict (on average) the percentage of stenosis from one method to another. The relationship between the NASCET and CC methods is linear, with a mean ratio of distal internal carotid artery to common carotid diameter of 0.62 (SD of 0.11). The variability in the diameter of the common carotid artery lumen stabilizes only beyond 2.5 common carotid diameter units (approximately 20 to 30 mm by conventional angiography) proximal to the bifurcation. Unexpectedly, the relationships between both the ECST and NASCET methods and ECST and CC methods were parabolic (P < .001). The reasons underlying these departures from linearity are uncertain.
The comparability of our results with those reported in the literature regarding the CC and NASCET methods provides further evidence of the reproducibility of methods measuring anatomic features that can be visualized on an angiogram. Disease of the internal carotid artery is one of the important causes of ischemic symptoms. Measuring the narrowest portion of the internal artery relative to the normal portion of the same artery, well beyond the bulb, is a logical method. Moreover, benefits of carotid endarterectomy for patients with 70% to 99% stenosis as determined by the NASCET method have been well established in a clinical trial. Converting from the NASCET method to the CC method, given that the CC method is neither superior nor easier to calculate, is not recommended.
文献中已提出三种不同的估计颈内动脉直径减小百分比（即狭窄）的方法。为了推荐一种用于从血管造影照片确定狭窄百分比的现行标准，对这些方法进行了进一步比较。
获取了112例患者的血管造影照片。对于每张血管造影照片，按照欧洲颈动脉外科试验（ECST法）、北美症状性颈动脉内膜切除术试验（NASCET法）以及使用颈总动脉管腔直径的方法（CC法）来估计狭窄情况。
尽管对于任何特定患者，由这三种不同方法得出的狭窄估计值之间存在很大差异，但可以（平均而言）预测从一种方法到另一种方法的狭窄百分比。NASCET法与CC法之间的关系是线性的，颈内动脉远端与颈总动脉直径的平均比值为0.62（标准差为0.11）。颈总动脉管腔直径的变异性仅在分叉近端超过2.5个颈总动脉直径单位（通过传统血管造影约为20至30毫米）时才稳定下来。出乎意料的是，ECST法与NASCET法以及ECST法与CC法之间的关系都是抛物线形的（P <.001）。这些偏离线性的潜在原因尚不确定。
我们的结果与文献中关于CC法和NASCET法的结果具有可比性，这为测量血管造影照片上可可视化的解剖特征的方法的可重复性提供了进一步证据。颈内动脉疾病是缺血症状的重要原因之一。相对于同一动脉的正常部分，在远超过球部的位置测量颈内动脉最狭窄的部分是一种合理的方法。此外，在一项临床试验中，由NASCET法确定的70%至99%狭窄患者行颈动脉内膜切除术的益处已得到充分证实。鉴于CC法既不优越也不容易计算，不建议从NASCET法转换为CC法。
