Effect Of Different Coronary Artery Stenosis On The Hemodynamics And Evaluation Of Hemodynamic Risk Factors Of Coronary Artery Stenosis

1.Background and ObjectiveCoronary Heart Disease(CHD)is the most common type of cardiovascular disease in clinical practice.It can cause stenosis and/or occlusion of coronary artery due to the appearance of atheromatous plaques.The supply of blood flow can be interrupted and leads to a series of severe myocardial ischemic conditions.The current incidence of this disease shows a rising trend.However,because of its complex pathogenesis,there is no clear and systematic theory to illustrate this.However,many studies have shown that hemodynamic factors may play an important role in the occurrence and development of atherosclerotic coronary heart disease.Therefore,this study intends to use the computational fluid dynamics(CFD)technique to simulate the hemodynamic changes in different degrees of stenosis of coronary artery and explore the hemodynamic alterations and blood flow distribution of different artery stenosis.In addition,we chose patients with moderate coronary artery stenosis as the study object.Compared the hemodynamic differences of stable and aggravated coronary artery stenosis,we aim to determine the hemodynamic characteristics of coronary artery stenosis.2.Materials and methods(1)The right coronary arterial geometric model was reconstructed with CT images.The model of stenosis was defined as 0%(normal vascular),30%(mildly stenosis),60%(moderate stenosis)and 90%(severe stenosis),respectively.The model of vascular hemodynamics was established respectively.Numerical simulations were performed to compare the hemodynamics between the different vascular models.(2)We retrospectively reviewed 80 patients with moderate coronary artery stenosis from January 2016 to December 2016 and follow-up imaging after one year.Compared the first and follow-up imaging results,determine the stenosis is further aggravated or not(defined as a stenosis severity >20%),and divide the stenosis into two groups(stable and aggravated).We created vascular model for each included case.Hemodynamic simulation,analysis,and quantitative calculations were performed,and hemodynamic parameters including the number of blood vortexes,velocity(V),wall shear stress(WSS)and wall pressure(WP)were performed for statistical analysis to determine the hemodynamic risk factors for coronary artery stenosis.3.Results(1)By comparing the hemodynamic numerical simulations of four kinds of stenosis,with the severe of the stenosis,the vortex flow becomes more obvious,the velocity of the flow showed faster in stenosis.In the proximal vascular region of stenosis,WP was gradually increased;on the other hand,the WP showed lower in the region after the stenosis.WSS distribution at the stenosis site always showed higher,and in the moderate and severe stenosis model,the high WSS region was found in the distal vascular region of stenosis,and the other distal vascular region of stenosis showed low WSS.Moreover,on the velocity and distribution of vascular blood flow,proximal and distal vascular region of the stenosis were also changed.(2)Among the 80 patients with moderate coronary artery stenosis,15 patients showed aggravated stenosis in follow-up imaging.In the stable group,the WP at the stenosis was slightly higher than that of the aggravated group(4.58±0.79 vs 4.33±0.74 kPa),the V value at the stenosis was slightly lower(0.52±0.18 vs 0.62±0.24 m/s),and the difference between the two groups was not statistically significant.However,the vortex number(1.62±1.00 vs 2.53±0.99,P<0.05)and the WSS value(4.40±0.95).Vs 5.92±1.37 Pa,P<0.05)showed significant lower than aggravated group.4.Conclusions(1)The coronary arterial hemodynamic model with diverse stenosis may simulate coronary arterial stenosis.As hemodynamic risk factors,the vortex of stenosis posterior flow and the high WSS in the distal vascular region of stenosis which showed in moderate and sever stenosis model maybe aggravated atherosclerosis of coronary artery,and further aggravated the vascular stenosis.(2)In patients with moderate coronary artery stenosis,further aggravated of the stenosis may be related to more vortex numbers and higher WSS values in the stenosis.