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

Abstract

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.

Single stem visceral debranching for complex aortic disease

“…To our opinion, this is the result of the hemodynamic optimization brought by the single-stem concept: a high flow in a large conduit. This provides our solution with the lowest possible hemodynamic impedance and is supported by a recent computational fluid model work 14 . In this work, Yuan and coll.…”

Single Stem Visceral Debranching for Complex Aortic Disease

“…This provides a solution with the lowest possible haemodynamic impedance and is supported by recent computational fluid model work. 10 Yuan et al. 10 showed that, from a haemodynamic standpoint, the use of the common iliac artery rather than aorta for the inflow site, leads to a dramatic decrease in flow to the visceral organs.…”

“… 10 Yuan et al. 10 showed that, from a haemodynamic standpoint, the use of the common iliac artery rather than aorta for the inflow site, leads to a dramatic decrease in flow to the visceral organs. Moreover, their haemodynamic model favoured the use of fewer branches to perfuse visceral organs.…”

Commentary: Physician-Modified Fenestrated/Branched EVAR and Hybrid Techniques for Acute Thoracoabdominal Aortic Pathologies: Inequality When Comparing Alternative Options With Different Philosophies Does Not Equal Lower Quality

“…On the contrary, RVR from the iliac artery did not alter the flow in the limbs but reduced the flow in the visceral vessels and changed the flow in the iliac artery, predisposing to stenosis of the bypass grafts. Furthermore, another computational study by Yuan et al 29 promotes the use of bilateral bifurcated grafts as having better performance in terms of shear stress, thus reducing neointimal hyperplasia, although they reduce flow in the celiac and mesenteric arteries. The impact of these studies is depicted in the follow-up patency of the hybrid group, which compares reasonably with other studies in which patency of visceral bypasses remains high in the long term, although issues with the patency of right renal bypasses have been reported irrespective of the configuration.…”