Objective The choice of treatment for unprotected left main bifurcation lesions depends largely on the severity of the lesion. SYNTAX score is a kind of severity of coronary artery disease evaluation method, which is based on coronary angiography and a complete anatomical evaluation. In this paper, the total perfusion is regarded as a reference to determine the severity of the lesion. From the perspective of hemodynamics, the severity of different types of bifurcation lesions is assessed. Methods The geometric multi-scale numerical simulation of different bifurcation lesions was carried out by coupling 3D model of the patient and the lumped parameter model. The flow of different branches, wall shear stress( WSS), oscillatory shear index( OSI) was extracted. By comparing these parameters, the severity of different types of bifurcation lesions was analyzed. Results The results showed that whether the branch ( circumflex ) the stenosis existed or not had an effect on the total perfusion. When the branch had lesion, the total perfusion volume decreased, which was consistent with the classification of the bifurcation lesion in the SYNTAX score. From the risk of deterioration, when the left main ( LM) was stenosis, the average WSS of the bifurcation area was relatively large, but OSI did not show a certain law. Conclusions The total perfusion of branch stenosis is smaller than branch normal. So the degree of myocardial ischemia of branch stenosis is more serious, but the risk of further development of stenosis has no significant difference.%目的 无保护左主干分叉病变的治疗方式选择很大程度上依赖于病变的严重程度.SYNTAX评分是基于冠脉造影图像对冠脉病变严重程度进行评价的方法,是一种完全解剖学的评价,缺少功能性的分析.本文以总灌注量作为判断病变严重程度的参考量,从血流动力学的角度对不同类型分叉病变严重程度做出评价.方法 采用患者三维模型(three-dimensional,3D)耦合个性化的集中参数模型(lumped parameter model,LPM,0D)对不同的分叉病变进行多尺度数值仿真计算,提取不同分支的流量、分叉区域的壁面切应力(wall shear stress,WSS)、壁面切应力振荡指数(oscillatory shear index,OSI)3个血流动力学参数,通过对比这些参数,从血流动力学的角度对不同类型分叉病变严重程度做出分析.结果 分支(回旋支)是否病变对总灌注量是有影响的,当分支存在病变时,总灌注量会降低,与SYNTAX评分中对分叉病变严重程度的分类是一致的.从恶化风险(WSS,OSI)来看,当左主干存在狭窄时,分叉区域平均WSS相对比较大,OSI并没有呈现出一定的规律.结论 分支存在狭窄的左主干分叉病变比分支不存在狭窄的病变总灌注量更小,心肌缺血程度更严重,狭窄进一步恶化并无明显差异.
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