远端侧-侧吻合冠脉搭桥术后血栓形成的数值模拟

Numerical Simulation of Thrombus Formation after Artery Bypass Grafting with Distal-End Side-to-Side Anastomosis

目的研究桥血管远端不同处理方式对其血栓生成的不同影响。方法针对远端侧-侧吻合(distal-end sideside anastomosis,DESSA)冠脉搭桥术,构建桥血管远端裁剪和不裁剪两种模型。使用生化反应的血液物质传输扩散模型,同时考虑血流动力学的切变率、流体滞留时间和血小板分布参数,评估血栓形成的可能性,使用数值模拟方法探讨DESSA冠脉搭桥中血栓生长。结果对于桥血管远端无裁剪处理的模型,血栓首先在桥血管远端内壁面上形成,随后向其内部生长,直至血栓占满大部分桥血管远端区域,血栓进入稳定状态,体积不再变化,生成血栓体积为15.051 mm^(3)。对于桥血管远端裁剪处理模型,生成血栓体积为7.352 mm^(3),同远端无裁剪模型相比,生成血栓体积减小51.2%。桥血管远端裁剪处理后,吻合口上方桥血管内壁上有血栓生成,壁厚约为0.16 mm,为桥血管半径的10.65%。上述两种术式中,桥血管远端区域形成多个漩涡流(流速小于10 mm/s),促进桥血管远端血栓形成;计算结果和临床报道的血栓形成区域相一致。结论临床DESSA冠脉搭桥术时,对桥血管远端进行裁剪处理,减小了桥血管生成血栓体积,但吻合口上方桥血管壁面生成血栓对冠脉搭桥术后影响还需进一步研究。

Objective To study the difference in thrombus formation at distal end of the graft with two different treatments.Methods For coronary artery bypass grafting with distal-end side-to-side anastomosis(DESSA),two models with or without distal end trimming of the graft were established.Using the blood substance transport and diffusion model considering biochemical reactions,combined with hemodynamics parameters of shear rate,fluid residence time,and platelet distribution,the possibility of thrombus formation was evaluated.Numerical simulation method was used to investigate thrombus growth in coronary artery bypass grafting with DESSA.Results For the model without distal end trimming of the graft,the thrombus was first formed on inner wall at distal end of the graft,and then grew inward until the thrombus occupied most of the graft region at distal end,which indicated that thrombus formation was in a stable state,and the volume of the thrombus didn’t change,the final volume of the thrombus was 15.05 mm^(3).For the model with distal end trimming of the graft,the final volume of the thrombus was 7.35 mm^(3),which was 51.2%smaller than that of the model without distal end trimming of the graft.Thrombus was formed on inner wall of the graft above the anastomosis for the model with distal end trimming of the graft,and the wall thickness was about 0.16 mm,which was 10.65%of the graft radius(1.50 mm).In the above two procedures,multiple vortices(blood flow velocity less than 10 mm/s)were formed in distal region of the graft,which further promoted thrombus formation at distal end of the graft.The area of thrombus formation obtained from numerical simulation was consistent with clinical investigation.Conclusions For clinical coronary artery bypass grafting with DESSA,the volume of the generated thrombus can be reduced for the model with distal end trimming of the graft.However,the effect of thrombus formation on inner wall of the graft above the anastomosis on coronary artery bypass grafting needs further study.