Type B Aortic Dissection in Marfan Patients after the David Procedure: Insights from Patient-Specific Simulation

Objective An elevated risk of acute type B aortic dissection (ATBAD) exists in Marfan syndrome (MFS) patients after the David procedure. This study explores hemodynamic changes in the descending aorta post-surgery. Methods A single-center retrospective review identified 5 MFS patients who experienced ATBAD within 6 years post-David procedure, alongside 5 matched MFS patients without dissection >6 years post-surgery. Baseline and post-operative CT/MRI scans were analyzed for aortic geometry reconstruction. Computational fluid dynamics simulations evaluated pre- and post-operative hemodynamics. Results Patients with ATBAD showed lower blood flow velocities, increased vortices, and altered velocity profiles in the proximal descending aorta compared to controls. Pre-operatively, median Time-averaged wall shear stress (TAWSS) in the descending aorta was lower in ATBAD patients (Control: 1.76 [1.50, 2.83] Pa, Dissection: 1.16 [1.06, 1.30] Pa, p=0.047). Post-surgery, neither group had significant TAWSS changes (Dissection: p=0.69, Control: p=0.53). Localized analysis revealed surgery-induced TAWSS increases near the subclavian artery in the dissection group (range: +0.30 to +1.05 Pa, each comparison, p<0.05). No such changes were observed in controls. Oscillatory shear index (OSI) and Relative residence time (RRT) were higher in ATBAD patients pre- and post-surgery versus controls. Conclusion Hemodynamics likely play a role in post-David procedure ATBAD. Further investigation into aortic geometry, hemodynamics, and post-operative ATBAD is vital for enhancing outcomes and refining surgical strategies in MFS patients.