Using CFD to Evaluate the Risk of Post-Stenotic Dilatation of the Aorta and to Predict Postoperative Outcomes

Abstract:
Objective: Following aortic coarctation, the distal aorta is susceptible to dilation, potentially leading to aortic aneurysms. This study develops computational models featuring varying severities of post-stenotic dilation and aorto-aortic bypass grafting scenarios, analyzing dilation risk and surgical outcomes through mechanical functional parameters. Methods: We utilized pre- and postoperative CTA data from patient who underwent aorto-aortic bypass grafting to construct models representing three levels of stenosis and three post-bypass configurations. Hemodynamic simulations were conducted to compare and analyze key mechanical parameters. Results: Our results indicate that increased stenosis severity correlates with higher proximal pressures, distal velocities, and Time-Averaged Wall Shear Stress (TAWSS), elevating the risk of dilation or rupture. Bypass grafting without ligation of the stenosed segment demonstrated reduced proximal pressures and flow velocities, as well as diminished high-velocity flow and vortices at the aneurysm site, suggesting superior postoperative outcomes compared to ligated grafts. The angle of the artificial grafts showed negligible effects on hemodynamic distributions. Conclusion: This research underscores the utility of computational fluid dynamics in assessing the risk of aortic dilation post-coarctation and in evaluating surgical intervention efficacy by examining the relationship between stenosis severity and hemodynamic parameters. Hemodynamic-based risk assessment of stenosis degree is a vital preoperative tool for predicting aortic dilation potential and informing surgical strategy. Furthermore, our analysis indicates that the choice of surgical technique in bypass grafting significantly influences postoperative prognosis, while minor variations in graft angle may not substantially affect hemodynamic outcomes.