VESS29. Impact of Proximal Seal Zone Length and Intramural Hematoma on Clinical Outcomes and Aortic Remodeling Following Thoracic Endovascular Aortic Repair for Aortic Dissections

Abstract

Thoracic endovascular aortic repair (TEVAR) has become the treatment of choice for aortic dissections in many centers. While adequate proximal seal is a fundamental requisite for TEVAR, there are insufficient data on the impact of the proximal seal length on patient outcomes. The goal of this study was to describe the proximal seal zone achieved during TEVAR for aortic dissections as well as its effect on clinical outcomes and aortic remodeling. A retrospective review was performed on all patients who underwent TEVAR for aortic dissections at a single institution from 2006 to 2016. Preoperative computed tomography (CT) was used to identify the entry tear, extent of dissection, and distances between the arch branches in three-dimensional centerline. Proximal seal zone length was calculated on postoperative imaging. Sequential postoperative CT scans were analyzed for remodeling of the true and false lumen aortic diameters over time. Clinical outcomes, including retrograde type A dissection (RTAD), death, and aortic reinterventions, were recorded. During the study period, 84 patients underwent TEVAR for aortic dissections. Indications for TEVAR were malperfusion (n = 12), aneurysm (n = 26), persistent pain (n = 33), rupture (n = 8), uncontrolled hypertension (n = 2), and other (n = 3). Mean follow-up was 14 months (range, 0-94 months). In 28 patients (33%), the aorta proximal to stent graft was without intramural hematoma, while the proximal seal zone in 56 patients (67%) was entirely in intramural hematoma. Proximal seal according to the manufacturers’ instructions for use (2 cm of normal aorta) was achieved in only six patients (7.1%). Thirty-nine patients (46%) would have required total arch debranching to obtain a 2-cm proximal seal. After TEVAR deployment in intramural hematoma, two RTADs underwent operative repair, and one patient had a sudden death. No RTADs occurred after TEVAR deployment in nondissected aorta without intramural hematoma. Overall reintervention-free survival was 52% at 24 months. Mean expansion of thoracic true lumen diameters were 151%, 177%, 191%, 202%, and 211% of baseline at the 1-, 6-, 12-, 24-, and 36-month follow-up, respectively. Regression of thoracic false lumen diameters was seen in 87%, 83%, 73%, 71%, and 70% at the 1-, 6-,12-, 24-, and 36-month follow-up. Complete thoracic false lumen thrombosis was seen in 55%. Aortic remodeling, such as false lumen thrombosis, true lumen expansion, and false lumen regression, was not different between the patients who had a proximal landing zone in the intramural hematoma and those who did not. Achieving a 2-cm proximal seal zone in TEVAR for aortic dissections often requires extensive arch debranching. Stent graft deployment with shorter than a 2-cm proximal seal zone in a normal aorta without intramural hematoma avoids RTAD, and induces aortic remodeling.