Hemodynamic differences and endoleak risk assessment of different angles of chimney stent graft deployment in chimney...

Chimney technique is an effective method for guaranteeing left subclavian artery (LSA) revascularization for patients receiving thoracic endovascular aortic repair. However, the complications like endoleak often occur after the chimney technique, and clinical studies have shown that they are closely related to the configuration of the chimney stent graft (SG). In this paper, we simulated the deployment of chimney SG with different angles and thoracic aortic SG, and analyzed the risk of complications according to numerical simulation results. Thoracic aortic SG and chimney SGs with different angles were designed based on patient-specific aortic geometry. The dynamic deployment process of SGs was simulated, followed by computational fluid dynamics (CFD) analysis to evaluate hemodynamic differences. Results indicate that the angle of chimney SG has little influence on the von Mises stress on the vascular wall. The endoleak flow rate at peak systole reached 11.15 ml/s in the 70° configuration, which is 1.80 times that of the 45° configuration. Meanwhile, the flow rate of LSA reached 5.94 ml/s in the 45° configuration, which is 1.21 times that of the 70° configuration. This indicates that the 45° configuration may reduce the risk of endoleak and flow obstruction to LSA. In addition, the relative residence time of 0° or 15° configuration is larger, suggesting a higher risk of thrombosis. This study employs virtual stent deployment and CFD analysis to predict the risk of complications associated with the deployment of chimney stents with different angles, potentially aiding surgeons in selecting the most appropriate surgical plan.