Hemodynamic factors of aortic dilatation after thoracic endovascular aortic repair for type-B aortic dissection

Objective: We aimed to investigate the hemodynamic factors associated with aortic dilatation following thoracic endovascular aortic repair (TEVAR) for type-B aortic dissection (TBAD). Methods: This retrospective study enrolled patients who developed aortic dilatation following TEVAR for TBAD, patients who did not develop aortic dilatation following TEVAR for TBAD, and healthy control subjects. Computed tomography angiography (CTA) images for the dilatation group were acquired at three time points: pre-TEVAR (Group A), 1-week post-TEVAR (Group B), and the most recent follow-up (Group C). For the non-dilatation group, CTA images were acquired pre-TEVAR (Group D) and 1 week post-TEVAR (Group E). The control group underwent a single CTA examination (Group F). Three-dimensional (3D) models were reconstructed from CTA images, and computational fluid dynamics (CFD) simulations were performed. The oscillatory shear index (OSI) at the ostia of the major arterial branches was defined as the primary CFD endpoint. Results: In the dilatation group, the pressures at the ostia of the brachiocephalic trunk, left common carotid artery, left subclavian artery, celiac trunk, superior mesenteric artery, bilateral renal arteries, inferior mesenteric artery, and bilateral common iliac arteries were lower in Group B than in Groups A and C. In the non-dilatation group, the pressures at the ostia of the brachiocephalic trunk, left common carotid artery, left subclavian artery, celiac trunk, superior mesenteric artery, left renal artery, inferior mesenteric artery, and right common iliac artery were higher in Group E than in Group D. The false lumen in Group B exhibited a larger region of high OSI compared with that in Group E. Conclusion: Elevated OSI in the false lumen is associated with a greater tendency toward aortic dilatation following TEVAR for TBAD. Patients with reduced true lumen pressure in the early post-TEVAR period show a corresponding trend toward subsequent aortic dilatation.