Aortic Wall Enhancement Detected by Contrast Computed Tomography Scan Predicts Aortic Remodeling after Conservative Therapy for Acute Uncomplicated Type B Dissection

Abstract

The Investigation of Stent Grafts in Aortic Dissection with extended length of follow-up trial showed that pre-emptive thoracic endovascular aneurysm repair (TEVAR) for the uncomplicated type B dissection (TBAD) in the subacute phase promotes aortic remodeling and avoids aortic-related death 5 years after onset. However, there are some patients with complete aortic remodeling (CAR) with optimal medical treatment (OMT) and severe complications after TEVAR such as retrograde type A dissection. Therefore, which patients should undergo pre-emptive TEVAR and optimal surgical timing are still under debate. We reported that aortic wall enhancement (AWE) after endovascular aneurysm repair for abdominal aortic aneurysm was associated with sac shrinkage. However, there is no report about the relationship between AWE and aortic dissection. Herein, we evaluated the relationship between AWE and acute TBAD. From March 2012 to May 2018, consecutive patients with acute TBAD were retrospectively collected. We retrospectively analyzed 35 patients with acute TBAD who were treated with OMT and without pre-emptive TEVAR in the subacute phase. AWE was defined as an increase of more than 20 Hounsfield units in mean computed tomography (CT) values, comparing images in delayed contrast-enhanced scans with those in plain scans evaluated within 3months from onset. The measurement points were all slices including the wall of the false lumen. The patients with traumatic dissection, type A dissection, acute complicated type B dissection, chronic (>12weeks) dissection, and those lost to follow-up within 3months from onset were excluded. The primary end point was spontaneous CAR under OMT, as determined by the latest contrast-enhanced CT scan. The median follow-up period from onset was 86weeks and there were 25 cases (71.4%) with AWE. Under OMT, CAR was observed in 20 patients (57.1%); this was significantly associated with abdominal branch dissection (6/15 [40%] vs. 2/20 [10%], P=0.050), number of tears more than 2 at onset (11/15 [73%] vs. 4/20 [20%], P=0.003), multiple tears at 1month after onset (9/15 [60%] vs. 4/20 [20%], P=0.020), maximal false lumen diameter at 1month after onset (14 vs. 8mm, P=0.025), and AWE within 3months of onset (7/15 [47%] vs. 18/20 [90%], P=0.010). Multivariate analysis demonstrated a significant difference with multiple tears at onset (P=0.014) and AWE within 3months of onset (P=0.047). AWE was associated with CAR under OMT for acute TBAD which is out of indication of pre-emptive TEVAR. Presence of AWE may be useful in predicting prognosis of TBAD.