量化侧支对内皮剪切应力估计值的影响。
Quantifying the effect of side branches in endothelial shear stress estimates.
作者信息
Giannopoulos Andreas A, Chatzizisis Yiannis S, Maurovich-Horvat Pal, Antoniadis Antonios P, Hoffmann Udo, Steigner Michael L, Rybicki Frank J, Mitsouras Dimitrios
机构信息
Applied Imaging Science Laboratory, Radiology Department, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Cardiovascular Division, University of Nebraska Medical Center, Omaha, NE, USA.
出版信息
Atherosclerosis. 2016 Aug;251:213-218. doi: 10.1016/j.atherosclerosis.2016.06.038. Epub 2016 Jun 23.
BACKGROUND AND AIMS
Low and high endothelial shear stress (ESS) is associated with coronary atherosclerosis progression and high-risk plaque features. Coronary ESS is currently assessed via computational fluid dynamic (CFD) simulation of coronary blood flow in the lumen geometry determined from invasive imaging such as intravascular ultrasound and optical coherence tomography. This process typically omits side branches of the target vessel in the CFD model as invasive imaging of those vessels is not usually clinically-indicated. The purpose of this study was to determine the extent to which this simplification affects the determination of those regions of the coronary endothelium subjected to pathologic ESS.
METHODS
We determined the diagnostic accuracy of ESS profiling without side branches to detect pathologic ESS in the major coronary arteries of 5 hearts imaged ex vivo with computed tomography angiography (CTA). ESS of the three major coronary arteries was calculated both without (test model), and with (reference model) inclusion of all side branches >1.5 mm in diameter, using previously-validated CFD approaches. Diagnostic test characteristics (accuracy, sensitivity, specificity and negative and positive predictive value [NPV/PPV]) with respect to the reference model were assessed for both the entire length as well as only the proximal portion of each major coronary artery, where the majority of high-risk plaques occur.
RESULTS
Using the model without side branches overall accuracy, sensitivity, specificity, NPV and PPV were 83.4%, 54.0%, 96%, 95.9% and 55.1%, respectively to detect low ESS, and 87.0%, 67.7%, 90.7%, 93.7% and 57.5%, respectively to detect high ESS. When considering only the proximal arteries, test characteristics differed for low and high ESS, with low sensitivity (67.7%) and high specificity (90.7%) to detect low ESS, and low sensitivity (44.7%) and high specificity (95.5%) to detect high ESS.
CONCLUSIONS
The exclusion of side branches in ESS vascular profiling studies greatly reduces the ability to detect regions of the major coronary arteries subjected to pathologic ESS. Single-conduit models can in general only be used to rule out pathologic ESS.
背景与目的
低内皮剪切应力（ESS）和高内皮剪切应力与冠状动脉粥样硬化进展及高危斑块特征相关。目前，冠状动脉ESS是通过对血管腔内血流进行计算流体动力学（CFD）模拟来评估的，该模拟基于血管内超声和光学相干断层扫描等侵入性成像确定的管腔几何形状。在CFD模型中，这一过程通常会忽略目标血管的侧支，因为对这些血管进行侵入性成像通常并无临床指征。本研究的目的是确定这种简化在多大程度上影响对冠状动脉内皮中承受病理性ESS区域的判定。
方法
我们利用计算机断层扫描血管造影（CTA）对5颗离体心脏的主要冠状动脉进行成像，确定了不考虑侧支时ESS分析检测病理性ESS的诊断准确性。使用先前验证的CFD方法，分别在不纳入（测试模型）和纳入（参考模型）所有直径>1.5mm的侧支的情况下，计算三条主要冠状动脉的ESS。针对参考模型，评估了每条主要冠状动脉全长以及仅近端部分（大多数高危斑块所在部位）的诊断测试特征（准确性、敏感性、特异性以及阴性和阳性预测值[NPV/PPV]）。
结果
使用不考虑侧支的模型时，检测低ESS的总体准确性、敏感性、特异性、NPV和PPV分别为83.4%、54.0%、96%、95.9%和55.1%，检测高ESS时分别为87.0%、67.7%、90.7%、93.7%和57.5%。仅考虑近端动脉时，低ESS和高ESS的测试特征有所不同，检测低ESS时敏感性低（67.7%）而特异性高（90.7%），检测高ESS时敏感性低（44.7%）而特异性高（95.5%）。
结论
在ESS血管分析研究中排除侧支会大大降低检测主要冠状动脉中承受病理性ESS区域的能力。单管模型通常仅可用于排除病理性ESS。
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