Anatomic feasibility of off-the-shelf thoracic single side-branched endograft in patients with blunt traumatic thoracic aortic injury

Objective: The advent of thoracic single side-branched endograft (TSSBE) has provided a treatment option to obviate the need for open cervical debranching of the left subclavian artery (LSA), thereby enabling total endovascular incorporation of the LSA during thoracic endovascular aortic repair (TEVAR). In a previous study of patients with type B aortic dissection who had required zone 2 TEVAR, the anatomic feasibility of this device was demonstrated to range from 28% to 35%, suggesting limited applicability of the currently available designs. The objectives of the present study were twofold: (1) to evaluate the anatomic feasibility of TSSBE in blunt traumatic thoracic aortic injury (BTAI) patients who would require LSA revascularization; and (2) to describe the anatomic characteristics of the supra-aortic arch branches that could be used to improve future device design. Methods: A retrospective review was performed of BTAI patients who had undergone TEVAR at a single institution from November 2013 to October 2018. Preoperative computed tomography angiograms were analyzed using three-dimensional reconstruction to quantify the aortic diameter, distance and arc length between branch vessels, and the LSA diameter and length. We calculated the proportion of patients who had met all aortic and LSA anatomic requirements for TSSBE proposed by investigational protocols. We also assessed the effect of anatomic requirement modifications on device suitability. Finally, we assessed the local anatomic relationship between the supra-aortic branches. Results: A total of 41 patients (63% men; median age, 39 years; range, 23-88 years; 68% normal aortic arch pattern, 32% bovine aortic arch pattern) with BTAI who had required TEVAR involving the LSA and were, thus, considered potential candidates for TSSBE were included. Of the 41 patients, 13 (32%; 7 with a bovine aortic arch and 6 with a normal aortic arch) had met all proposed aortic and LSA anatomic requirements for TSSBE. An appropriate aortic diameter, LSA diameter, and LSA length to its first branch were observed in 100%, 95%, and 66% of the patients, respectively. An insufficient distance between the arch branch vessels, observed in 41%, was the most common exclusionary criterion. The median clock-face position of the LSA was 12:00 (interquartile range, 30 minutes) in the normal arch group and 11:45 (interquartile range, 15 minutes) in the bovine arch group. Conclusions: Despite the numerous potential advantages of TSSBE, only 32% of patients with BTAI requiring LSA revascularization had met all the aortic and LSA anatomic requirements, justifying the need for additional designs. Better characterization and mapping of the aortic arch branches will improve future device design and application.