外周动脉斑块钙化程度对血管内介入治疗的影响

The Effect of Peripheral Artery Plaque Calcification on Intravascular Interventional Therapy

下肢外周动脉疾病血管内介入治疗失效是临床中亟需解决的一个关键问题,斑块的钙化程度是决定其治疗效果的一个重要因素。采用数值模拟的方法,通过将支架分别置入到含有不同程度(轻度、中度、重度)钙化斑块的下肢病变动脉中,探讨肢体在直立和运动过程中斑块和管壁的受力状态,评估斑块钙化的严重程度对治疗结果的影响。结果表明:含有钙化斑块的动脉置入支架后,在肢体运动中,位于动脉弯曲外侧的斑块处于疲劳状态,极有可能发生结构失效而破裂,其中中度钙化的斑块主应力峰值最高。3种钙化斑块最大塑性等效应变均发生在斑块的最狭窄处,其中重度钙化的斑块在直立和运动状态下均具有最高的塑性应变,狭窄率最低。轻度和重度钙化斑块所在的动脉具有相似的力学特性,含有中度钙化斑块的动脉最易发生损伤,其损伤部位位于斑块中间最狭窄处及斑块与健康动脉相连接处。从力学生物学角度对钙化程度不同的斑块病变动脉易发生破裂部位机理做了综合评价和阐述,为临床选取不同的治疗策略及预后提供了参考依据。

The failure of endovascular interventional therapy for lower extremity peripheral arterial disease is a key problem that needs to be solved urgently in clinic.The calcification degree of plaque is an important factor to determine the therapeutic effect.In this study,numerical simulation was used to investigate the stress state of the plaque and the artery wall during the upright and movement of the lower extremity after the stent was placed into the diseased arteries with calcified plaques(light,moderate,and heavy),and to evaluate the effect of the severity of the plaque calcification on treatment outcome.The results show that the plaque located on the lateral side of the curved artery was in fatigue state after the stent implantation during limb movement,and rupture probably occurs owing to structural failure,among which the plaque with moderate calcification had the highest peak principal stress.The maximum plastic equivalent strain of the three kinds of plaque occurred at the narrowest part of the plaque,and the heavy calcified plaque had the highest plastic strain with the lowest stenosis rate in the upright and moving state.The arteries with light and heavy calcified plaques have similar mechanical properties.Arteries with moderate calcified plaques are most susceptible to damage in the narrowest part of the plaque and the junction between the plaque and healthy arteries.This study provides a comprehensive evaluation and elaboration of the mechanism of the location of the lesion artery prone to rupture with plaque of various calcification degree from the perspective of mechanical biology,providing a guideline for choosing different treatment strategies and prognosis in clinic.