目的 研究胸主动脉腔内修复术中开窗技术与平行支架技术对主动脉弓及弓上血管的血流动力学影响,并对比不同术式的差异。 方法 研究 4 例采用不同术式(开窗技术、烟囱技术和潜望镜技术)重建弓上分支的主动脉弓部病变患者,通过随访影像数据建立三维几何模型。 将二维相位对比磁共振成像测量的血流量作为升主动脉入口和弓上血管出口的边界条件。 使用 3 单元 Windkessel 模型获得降主动脉出口的压力波形作为边界条件。 通过计算流体动力学(computational fluid dynamics,CFD)仿真获得弓上血管压力、分支支架入口速度矢量以及相对滞留时间等血流动力学参数。 结果 潜望镜支架的压力变化最大,其次是开窗支架,烟囱支架的压力变化最小。 开窗 支架和潜望镜支架的入口流速不均匀,容易形成涡流,烟囱支架入口流速均匀。 开窗支架外壁远心侧、“沟槽”部位、烟囱支架和潜望镜支架与血管壁贴合处相对滞留时间偏大。 结论 开窗支架和潜望镜支架内外壁压差较大,建议使用球扩支架。 烟囱支架内外壁压差较小,建议使用自膨支架。 本文预测的术后血栓形成位置与临床随访数据较为一致,故有可能用于主动脉弓部病变介入治疗的手术规划和风险评估。
Objective To explore hemodynamics of the aortic arch and supraarch vessels after thoracic endovascular aortic repair with fenestration and parallel grafts techniques, and compare the differences of these techniques. Methods Four patients with aortic arch lesions whose supraarch vessels were reconstructed by different surgical techniques (fenestration, chimney and periscope) were studied, and three-dimensional (3D) geometric models were established based on postoperative image data. The physiological flow obtained from twodimensional (2D) phase contrast magnetic resonance imaging were imposed on the ascending aorta inlet and the supraarch vessels outlets. The pressure waveform of 3-element Windkessel model was imposed on the descending aorta outlet. Through computational fluid dynamics ( CFD ) simulations, the hemodynamic parameters were obtained, including the pressure of supraarch vessels, the velocity vector of the stent inlet, and the relative residence time. Results The pressure change of the periscope stent was the largest, followed by the fenestration stent, and the pressure change of the chimney stent was the smallest. The velocity of the fenestration and periscope stent inlet was uneven, which might form vortex. The velocity of the chimney stent inlet was even. The high relative residence time concentrated in distal end of the fenestration stent outer wall, the ‘gutter’ part, and the place where the chimney and periscope stent adhered to the vessel wall. Conclusions The pressure difference between the inner and outer walls of the fenestration and periscope stent was high, so it was recommended to use the balloon-expandable stent. The pressure difference between the inner and outer walls of the chimney stent was low, so it was recommended to use the self-expanding stent. The predicted location of thrombosis was consistent with the clinical follow-up data, so it may be used for surgical planning and risk assessment of interventional treatment of aortic arch lesions.
卢 楷,孙晓凡,彭 臣,司 逸,单 艳,符伟国,王盛章.开窗技术与平行支架技术治疗主动脉弓部病变的血流动力学研究[J].医用生物力学,2023,38(2):360-367复制