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 exists in patients with Marfan syndrome after the David procedure. This study explores hemodynamic changes in the descending aorta postsurgery.

Methods: A single-center retrospective review identified 5 patients with Marfan syndrome who experienced acute type B aortic dissection within 6 years after the David procedure, alongside 5 matched patients with Marfan syndrome without dissection more than 6 years postsurgery. Baseline and postoperative computed tomography and magnetic resonance scans were analyzed for aortic geometry reconstruction. Computational fluid dynamic simulations evaluated preoperative and postoperative hemodynamics.

Results: Patients with acute type B aortic dissection showed lower blood flow velocities, increased vortices, and altered velocity profiles in the proximal descending aorta compared with controls. Preoperatively, median time-averaged wall shear stress in the descending aorta was lower in patients with acute type B aortic dissection (control: 1.76 [1.50-2.83] Pa, dissection: 1.16 [1.06-1.30] Pa,  = .047). Postsurgery, neither group had significant time-averaged wall shear stress changes (dissection:  = .69, control:  = .53). Localized analysis revealed surgery-induced time-averaged wall shear stress increases near the subclavian artery in the dissection group (range, +0.30 to +1.05 Pa, each comparison,  < .05). No such changes were observed in controls. Oscillatory shear index and relative residence time were higher in patients with acute type B aortic dissection before and after surgery versus controls.

Conclusions: Hemodynamics likely play a role in post-David procedure acute type B aortic dissection. Further investigation into aortic geometry, hemodynamics, and postoperative acute type B aortic dissection is vital for enhancing outcomes and refining surgical strategies in patients with Marfan syndrome.