Objective To evaluate the short-term outcomes of thoracic endovascular aortic repair (TEVAR) with outer branched and inner branched endografts in the treatment of Stanford type B aortic dissection (TBAD), and to analyze the effects of endografts on blood flow status of aortic dissection by computational fluid dynamics (CFD). Methods The clinical data of TBAD patients treated with outer branched endograft technology in outer branched endograft group and inner branched endograft technology in inner branched endograft group in Department of Vascular Surgery Tianjin Medical University General Hospital from May 2018 to December 2021 were collected, and the short-term results of two groups were analyzed retrospectively. Based on CT angiography images of patients in two groups, one typical case in each group was selected to construct personalized 3D model and CFD numerical simulation was performed. The parameters including flow field velocity distribution, wall pressure and wall shear stress (WSS) before and after surgery were compared and analyzed. Results A total of 55 cases with TBAD were enrolled, consisting of 49 cased in outer branched endograft group and 6 cases in inner branched endograft group. There was no statistical difference in baseline data between two groups, and surgical success rate were both 100%. Reconstruction of left subclavical artery(LSA) simple was 41(83.7%) cases in outer branched endograft group and all 6 cases in inner branched endograft group. In outer branched endograft group there were 5 cases with reconstruction of left common carotid artery (LCCA) combined with bridging carotic clavical artery, 2 cases with reconstruction of LCCA combined with LSA embolism, and 1 case with reconstruction of LCCA combined with LSA window. Four cases were lost during follow-up in outer branched endograft group. There were no significant differences in the aorta-related mortality rate (P=1.000), branch patency rate (P=1.000) and avoidance of secondary intervention of target vessels between the two groups during the perioperative period and follow-up period (P=0.298). After endograft implantation of two groups the flow field disturbance in dissection lesions improved significantly, aortic blood flow pattern restored normal, and local abnormally increased WSS decreased. However, the interference of inner branch on aortic arch and blood flow of branch was more obvious than that of outer branch. Conclusions Both outer branched endograft and inner branched endograft TEVAR for reconstruction of LSA had good short-term results in the treatment of TBAD. Compared with inner branched endograft, outer branched endograft has a higher anatomical fit and can restore the normal blood flow to a greater extent for aortic arch.
