Displacement Forces in Different Proximal Landing Zones for Thoracic Endovascular Aortic Repair: Towards Patient-Specific Assessment

Thoracic endovascular aortic repair (TEVAR) is one of the main treatments, together with open aortic repair, for thoracic aortic aneurysm. This procedure is associated with low procedural morbidity and mortality and provides satisfactory mid-term results. However, identifying the optimal location for device deployment before the operation remains essential. In previous studies, computer simulations were used to examine the hemodynamic stress linked to different areas of the arch, pinpointing regions unsuitable for TEVAR delivery. Computational fluid dynamics (CFD) simulations suggest that zone 3 poses the most challenges for delivering endograft in type III arches, as it is considered a hostile region from biomechanical and hemodynamic perspectives. Morphologically, type III aortic arch shows a more pronounced curvature and a lower position of the arch, resulting in increased separation between the ascending and descending aorta. However, these studies utilized 3D geometrical models reconstructed from computed tomography angiography scans. Still, the flow boundary conditions were based on existing data rather than the specific hemodynamic characteristics of the patient. To bridge this gap, the present study uses MRI flow wave data to compute displacement forces (DFs) for each proximal landing zone. We found that zones 0 and 3 exhibited a high magnitude of displacement forces. Still, only zone 3 was identified as the most hemodynamically stressed area when the force was normalized for the lumen area. Furthermore, there was a significant discontinuity in the upward components of DFs between zone 2 and zone 3. The patient-specific assessment of displacement forces enabled us to identify suboptimal areas for TEVAR delivery, suggesting that personalized computer simulations could greatly enhance preoperative planning for TEVAR procedures.