Aortic Healing Appears to Occur Rapidly after Successful Endovascular Sealing of Blunt Thoracic Aortic Injury

Abstract

The traumatic nature of blunt thoracic aortic injury (BTAI) would suggest that healing of the aorta would occur once the injured area is shielded from aortic pressure. This would be in contrast to degenerative aortic diseases which often continue to degenerate despite coverage. We hypothesize that after successful thoracic aortic endografting (TEVAR) that the aorta rapidly heals itself leaving minimal to no trace of the residual injury. BTAI that were successfully covered with TEVAR from 2006 to 2019 were collected. Those with failed sealing or a lack of follow-up scans were excluded. Centerline aortic diameters were measured at healthy aorta 1cm above (D1) and below the injury (D3) and at the widest point of injury (D2) on preoperative and initial postoperative computed tomography (CT) scans. Postoperative CTs were examined for residual signs of aortic injury including residual periaortic hematoma, persistent thrombosed pseudoaneurysm, or thickened aortic wall. Diameter changes in the healthy and injured aortic segments were compared pre and post TEVAR. Aortic diameter changes were analyzed with the Student's t-test. Twenty four patients were identified with sealed BTAI. The mean graft diameter was 24.2±3.2mm with oversizing of 10.74±6.1 % at D1 and 19.52±10.22 % at D3. Postoperative CTs occurred at 61.25±123.6days with one outlier at 602days. Injured aortic segments (D2) had significantly larger diameters compared to D1 (28.94±5.08mm vs. 22.14±3.08mm, P<0.001). After TEVAR, 23/24 (95.8%) had no residual radiographic evidence of aortic injury by 2months. One patient had a persistent thrombosed pseudoaneurysm likely due to more than 50% disruption of the aortic wall. Post TEVAR, there was a significant diameter reduction at D2 by 13.8% (29.10±5.27mm vs. 24.8±4.2mm, P<0.001) which was within 2.45% of the mean stent graft diameter. The healthy aorta dilated to accommodate the graft by 9% at D1 (21.9±3.0 vs. 23.7±2.5mm, P<0.001) and 17% at D3 (20.6±3.4mm vs. 23.6±3.2mm, P<0.001). TEVAR promotes rapid aortic healing in BTAI with no evidence of residual aortic injury suggesting that a long-term seal is not necessary. The healthy aorta dilates to the stent graft size, as expected, whereas the injured aortic segment heals around the stent graft and assumes its diameter as well. Massive disruption of the aortic wall may preclude early healing.