不同钙化模式对经导管主动脉瓣膜植入效果影响的数值模拟研究

目的 通过有限元方法评估不同钙化模式对经导管主动脉瓣膜植入效果的影响。方法根据钙化斑块在主动脉瓣叶上的位置不同，建立对合线钙化模型、附着线钙化模型和圆圈钙化模型3种不同钙化形式的主动脉根部模型。使用ABAQUS软件仿真自膨胀经导管主动脉瓣膜植入3个钙化模型中的过程，分析不同钙化模型对主动脉根部应力、瓣架变形以及瓣周间隙的影响。结果 圆圈钙化模型中钙化斑块的最大主应力最大，为18.42 MPa，可能导致假体植入后发生脑卒中的风险更高；圆圈钙化模型的瓣架变形程度也最大，可能导致更差的假体耐久性；附着线钙化模型的瓣周间隙面积为37.2 mm2，超过其他模型的2倍，植入后出现严重瓣周返流的风险可能性更高。结论 不同的主动脉瓣叶钙化模式与经导管主动脉瓣膜植入后的主动脉根部应力、瓣架变形以及瓣周间隙有关，对术后并发症和假体耐久性产生影响。研究结果为临床上经导管主动脉瓣膜植入术术后效果的预测提供参考。
Objective To investigate the effect of different calcification patterns on the outcome of transcatheter aortic valve implantation (TAVI) by the finite element method. Methods Three calcified human aortic root models (coaptation line calcification model, attachment line calcification model and circular calcification model) were developed according to the location of calcified plaques on the aortic valve leaflets. The processes of self-expanding transcatheter aortic valve implanted into the 3 calcified models were simulated by ABAQUS software. The effects of different calcification patterns on the aortic root stresses, valve frame distortions and paravalvular gaps were analyzed. Results Circular calcification model had the largest maximum principal stress on calcified plaques (18.42 MPa), which might result in a higher risk of stroke after implantation; the circular calcification model also had the greatest distortion of the valve frame, which might lead to worse prosthetic durability; the paravalvular gaps area of the attachment line calcification model was 37.2 mm2, which was more than twice that of the other 2 models, causing more serious paravalvular regurgitation. Conclusions Different aortic valve calcification patterns are related to aortic root stresses, valve frame distortions and paravalvular gaps after TAVI, which will have an impact on postoperative complications and prothesis durability. The research findings provide references for the prediction of clinical outcome after TAVI.