Precise plan of hybrid treatment for thoracoabdominal aortic aneurysm: Hemodynamics of retrograde reconstruction visceral arteries from the iliac artery

Hybrid visceral-renal debranching procedures with endovascular repair have been proposed as a less invasive alternative to conventional thoracoabdominal aortic aneurysm or dissection (TAAA or TAAD) surgery. Up to now, there has been no information about the hemodynamic effects of retrograde visceral reconstruction (RVR) for Crawford type II/III/IV TAAA patients undergoing hybrid treatment. The aim is to provide insights in the abnormal hemodynamics of RVR from unilateral or bilateral common iliac arteries (CIAs). Idealized three-dimensional AAs with RVR from unilateral CIA or bilateral CIAs were generated and computationally simulated. The results show that RVRs from CIA lead to a dramatic decrease in flow to the visceral organs compared with a healthy AA and that the anastomosis region is most dangerous to graft occlusion and the initiation of an aneurysm. In addition, compared with a quar-furcated graft, the employment of bilateral bi-furcated grafts have better performance in terms of the wall shear stress (WSS) and flow filed but result in less flow to the celiac and mesenteric arteries. This study has revealed the potential risks after an RVR operation, and points out the advantages and disadvantages of different approaches for the visceral reconstruction, which the vascular surgeons are not fully aware of. According to our results, bilateral bi-furcated grafts are recommended to the TAAA patients when the CIAs are unique inflow sites for visceral reconstruction. A precise plan with patient specific for TAAA or TAAD will be designed for better long-term outcome.