Anatomic Suitability for Standard, “Off-the-Shelf” Thoracic Single Side-Branched Endograft in Patients With Type B Aortic Dissection

Abstract

Treatment of type B aortic dissections with thoracic endovascular aortic repair (TEVAR) has been adopted in many centers with the goal of covering the proximal entry tear. Coverage of the left subclavian artery is commonly required to achieve a dissection-free proximal seal zone. A novel thoracic single side-branched (TSSB) endograft offers a potential off-the-shelf option to achieve total endovascular incorporation of the left subclavian artery during zone 2 TEVAR. The aim of this study was to determine what percentage of patients with type B aortic dissection who require zone 2 TEVAR meet the anatomic requirements for this device. All consecutive patients undergoing TEVAR for type B aortic dissections at a single institution from 2006 to 2016 were evaluated. Three-dimensional centerline reconstruction of preoperative computed tomography angiography was performed to identify the diameter of the aorta, distances between branch vessels, diameter of the target branch vessel, and location of the primary entry tear. Only patients who required zone 2 TEVAR were included in the analysis. The primary outcome was percentage of patients who met all anatomic requirements for the TSSB endograft. The specific requirements leading to nonsuitability were also calculated. Eighty-seven patients who underwent TEVAR for type B aortic dissection were reviewed; 57 of 87 would have required zone 2 TEVAR. Indications for TEVAR were malperfusion (12), aneurysm (15), persistent pain (22), rupture (3), uncontrolled hypertension (5), and other (3). Mean follow-up was 19 months (range, 1-72 months). Only 17 patients (30%) met all the requirements for anatomic suitability (Fig). The reasons for failing anatomic suitability were covered stent graft length proximal to the branch portal (61%), aortic diameter at the proximal seal zone (11%), left subclavian diameter (16%), left subclavian length to its first branch (14%), and access vessel diameter (40%). Although the standard TSSB endograft can allow a more proximal seal zone and eliminate the need for open aortic arch debranching, only 30% of patients with type B dissection who require zone 2 TEVAR meet all the anatomic requirements for this device. The most common reason for failure of anatomic suitability is the proximity of the left carotid to the left subclavian origin.