基于CT成像的冠状动脉分叉病变的血流剪切力研究

Wall shear stress (WSS) plays an important role in the formation of atheromatous plaque. Coronary bifurcation lesions have complex and unique hemodynamic characteristics, in favor of the formation of atheromatous plaque and presence of in-stent intimal hyperplasia. Previous studies were limited to the correlation between WSS with a single morphological feature of coronary bifurcation lesions, the conclusions were inconsistent..On the other hand, calculation of WSS based on CT data has advantages,including being noninvasive and repeatable.We enrolled 26 cases of coronary bifurcation lesions, performing calculatin of WSS by using CT data, which is now in the stage of data analysis. In addition, there was basis between WSS studies of bifurcation lesions by CT imaging, due to the exclusion of lateral branch during the data analysis procedure.We carried out a preliminary study: two data groups were set to calculate the WSS, the group of “side branch included” and the group of “side branche excluded”. Our study proved that the method without including sida branch data underestimated the WSS.The results have been submitted to international journal..By using wall shear stress calculation based on CT imaging, the aim of this study is to analyze the correlation between the full morphological features and WSS of coronary bifurcation lesions, predict regression and progress of plaque depending on WSS, and guide interventional treatment.

血流剪切力在粥样斑块形成中起重要作用。血管分叉具有复杂、独特的血流动力学，易造成粥样斑块的形成，植入支架后亦易产生支架内膜增生。以往的剪切力研究局限于冠脉分叉病变的某单一形态学特征与剪切力之间的关系，其结论不尽相同。另一方面，利用CT数据进行剪切力运算无创、可重复，但技术要求较高。我们先期收集26例冠脉分叉病变的CT图像，进行剪切力计算，现处于数据分析阶段。另外，以往依据CT图像的分叉病变的剪切力研究，往往不将侧枝包含在内，造成了几项研究结果互相矛盾。我们针对该疑问实施了一项前期研究：研究分别进行包括侧枝的冠脉树重建和不包括侧枝的单支重建，发现单支重建方法低估了剪切力。研究结果已投国际前沿杂志。本课题将借助基于CT图像的血流剪切力计算这一先进的技术手段，研究冠脉分叉病变完整的形态学特征与血流剪切力之间的关系，建立回归分析模型，达到能够凭借剪切力预测斑块生成发展，并帮助优化介入治疗方案。

本项目团队研究、确立了适合冠状动脉的血流动力学的模型，完善了基于单一冠脉CT图像的血流动力学计算方法，证明对于冠脉轻至中度狭窄的病变，基于CTA数据的冠脉剪切力计算可以达到与常规DSA血管造影相同的效果，并基于相同的血流动力学模型，将其拓展至了血流储备分数的计算，经过与有创性冠脉造影数据对照，证明计算结果准确。.另外，冠脉搭桥术后桥血管的闭塞一直是临床研究的热点。而桥血管的血流动力学人体研究非常少，与桥血管通畅与否的的研究更是未见，本研究创新性的将冠脉剪切力技术应用于真实冠脉搭桥病人的围手术期桥血管，测量、分析围手术期桥血管的剪切力，并与术后一年桥血管的通畅与否进行对照。研究将入组病例按一年后的桥血管通畅与否分为通畅组和闭塞组，发现通畅组围手术期桥血管远段的 WSS值明显高于闭塞组 (4.43 vs 2.56 pascal, p<0.05)。通畅组内远段桥血管的WSS值高于近段桥血管的WSS值，而闭塞组无上述特点。进而研究提示：围手术期的桥血管剪切力本身的值大小及其分布特征，与桥血管一年通畅率相关。