Computational Fluid Dynamics-Driven Comparison of Endovascular Treatment Strategies for Penetrating Aortic Ulcer.

Background: Penetrating aortic ulcer (PAU) is an acute aortic syndrome characterized by a high rupture risk. There are several PAU-treatment procedures indicated for the management of this pathology associated with different effects on vessel morphology and hemodynamics. A deep evaluation of the different types of treatment may be helpful in decision making. Computational Fluid Dynamics (CFD) is a powerful tool for detailed inspection of cardiovascular diseases. The aim of this work was to implement a comparative analysis based on CFD evaluation of the effects of two type of PAU treatments. Methods: Thoracic endovascular aortic repair (TEVAR) with a left subclavian artery (LSA) branched aortic endograft (SBSG) and a hybrid approach including TEVAR and carotid-LSA bypass were considered. Aortic anatomical models were created from computed tomography (CT) images acquired before and after PAU treatment with SBSG for three patients. Starting from these models, a new aortic geometry corresponding to the outcome of the hybrid strategy was generated. Morphological analysis and CFD simulations were carried out for all aortic models to evaluate LSA outflow for the same predefined boundary conditions. Results: Reductions in LSA diameter were found between aortic models before and after the SBSG (18.2%, 20.8%, and 12.4% for CASE 1, CASE 2, and CASE 3, respectively). The flow rate at LSA changed between pre-configuration and aortic configuration after the PAU treatments: an averaged decrement of 1.08% and 7.5% was found for SBSG and the hybrid approach, respectively. The larger increase in pressure drop between the aortic arch and the LSA extremity was shown in the hybrid approach for all cases. Conclusions: CFD simulations suggest that SBSG preserves LSA perfusion more than a hybrid strategy and has less impact on thoracic aorta hemodynamics.