Multiphase fluid-solid interaction analysis of stent-vessel-blood based on type B aortic dissection

Thoracic endovascular aortic repair (TEVAR) is an effective treatment method for Stanford type B aortic dissection (TB-AD). In the investigation of treatment methods of TEVAR, numerical simulation technologies play a pivotal role. However, current finite element simulations of AD often use overly simplified vascular models and fail to adequately consider the complex interactions between stents, vessels, and blood. In this study, a Boolean operation was adopted to establish 3D models of TB-AD based on patient-specific CT images. The 3D software was used to construct 5, 6, and 8-peak stent grafts. A finite element method was applied to simulate the compression and release processing of stent graft deployment. Finally, a fluid-solid interaction module was constructed for the multiphase fluid-solid interaction simulation. The results showed that after stent graft deployment, the cross-sectional area of the vessels in the aortic coarctation region increased by 60.0%-65.5%. The maximum blood flow velocity in the true lumen decreased from 1.585 m/s to 1.125-1.238 m/s. The maximum blood pressure increased from 1574 Pa (true lumen) and 1853 Pa (false lumen) to 2021-2165 Pa (true lumen). The distribution of wall equivalent stress was more uniform, and the maximum value decreased from 0.5475 MPa to 0.1667-0.1758 MPa. The maximum equivalent stress of the stent was 3.815-4.315 MPa. Comprehensive comparisons showed that the eight-peak stent graft exhibited lower equivalent stress and superior improvement in vascular morphology, blood flow, and vessel stress, providing an optimal stent graft option for the clinical treatment of TB-AD.