Hemodynamic Study On The Effect Of Coronary Stenosis Length And Left Main Bifurcation To Lesion Severity

The choice of treatment of coronary heart disease depends on the severity of coronary artery disease.Coronary artery stenosis rate is currently used to assess the severity of coronary heart disease.But in anatomical,there is no absolute correlation between coronary artery stenosis rate and myocardial ischemia,so there are many factors affecting the severity of coronary artery disease.In this paper,the hemodynamic effects of stenosis length and bifurcation type on severity of coronary heart disease were investigated by geometric multi-scale simulation which coupled three-dimensional model and the personalized lumped parameters model.The research is as follows:1.Hemodynamic effect of stenosis length on the severity of coronary artery disease.Six stenosis rate of 50% models whose lesion length were 3mm,5mm,10 mm,15mm,20 mm and 25 mm,respectively,were established on left anterior descending of the three-dimensional(3D)model.Then the finite element analysis is carried out by coupling the 3D model and the lumped parameter model(LPM).Flow rate,wall shear stress(WSS),and the oscillatory shear index(OSI)were extracted.The severity of the coronary artery was analyzed by comparing these three parameters.2.Hemodynamic effect of stenosis length with coronary artery bypass surgery(CABG)on the graft.Six different lesion length models of left internal mammary artery bypass surgery were established on the 3D model.Then the finite element analysis is carried out by coupling the3 D model and the LPM.Flow rate,WSS,and the OSI were extracted.The hemodynamic atmosphere of graft was analyzed by comparing these three parameters.3.Hemodynamic effect of bifurcation on the severity of coronary artery disease.Seven models of stenosis rate of 80% were established on the 3D model of patients.Then the finite element analysis is carried out by coupling the3 D model and the LPM model.Flow rate,WSS,and the OSI were extracted.Then the finite element analysis is carried out by coupling the 3D model and the LPM.Flow rate,WSS,and the OSI were extracted.The severity of the coronary artery was analyzed by comparing these three parameters.From the study of stenosis length,it can be seen that the total perfusion volume decreases slightly with the increase of the stenosis length,and it remains unchanged after 15 mm.The maximum change is about 9ml / min and the maximum rate of change is 3.85%.With the increase of stenosis length,the area average wall shear stress increases,but the OSI decreases;when choosing the coronary artery bypass graft,with the length of stenosis increasing from 3mm to 15 mm,the competitive flow was decreasing,and the change was significant.The maximum change was 23.56 ml / min,and the maximum rate of change was 60.83%.But when the stenosis reached 15 mm,competitive flow stays stable.The area average wall shear stress of graft is growing and OSI changes a little.From the study of bifurcation lesions,in the view of total perfusion,the seven lesions are different greatly.The results showed that when the branch had lesion,the total perfusion volume decreased,which was consistent with the classification of the bifurcation lesion in the SYNTAX score.In the view of WSS and OSI,there was no significant law in different models.The impact of stenosis length on myocardial ischemia is relatively small,but due to the existence of competitive flow,when choosing the CABG,with the increase of stenosis length,long-term patency of graft will increase.Though the effect of lesion length on the severity of coronary heart disease is relatively small,but from the treatment point of view,it is better to choose coronary artery bypass surgery for a longer stenosis.For bifurcation lesions,the total perfusion of stenotic-branch model was smaller.In this paper,through studying hemodynamic influence of length of coronary lesions and left main bifurcation lesions on the severity of coronary artery disease,it provides guidance for the clinical treatment of moderate stenosis lesions and a theoretical basis for the assessment of the severity of coronary heart disease.