The Characteristics of Aortic Remodeling after Thoracic Endovascular Aortic Repair using Two-stent Graft Implantation for Stanford Type B Aortic Dissection

  Objective  To investigate the characteristics of aortic remodeling after thoracic endovascular aortic repair using two-stent graft implantation (TEVAR-TSI) for Stanford B aortic dissection.

  Methods  The clinical and imaging data of 128 patients who underwent TEVAR-TSI for Stanford B aortic dissection in the First Affiliated Hospital of Hebei North University from January 2013 through May 2019 were retrospectively collected. CT images were obtained before (T₀) TEVAR-TSI and, 1 week (T₁), 3 months (T₂), 6 months (T₃), 1 year (T₄) after TEVAR-TSI. The maximum diameter of the true lumen and false lumen in the short axis view was accessed at five levels: L₁: the level of primary tear entry, L₂: the level of the bronchial bifurcation, L₃: the level of the distal of the first stent-graft, L₄: the level of the celiac trunk, L₅: the level of the lowest renal arteries. The false lumen thrombosis in the thoracic aorta and abdominal aorta were assessed at different times, the false lumen and true lumen changes in diameter were evaluated between the preoperative and postoperative CT scan.

  Results  The stented segment of the descending thoracic aorta was evaluated (L₁-L₃): The true lumen diameter showed an increasing trend and the false lumen diameter showed an decreasing trend at levels L₁, L₂, and L₃, the change of true lumen diameter was positively correlated with the follow-up time (r=0.721, 0.827, 0.893, P<0.05), and the change rate of true lumen diameter was positively correlated with the follow-up time (r=0.763, 0.818, 0.902, P<0.05), and the change of false lumen diameter was negatively correlated with the follow-up time (r=−0.750, −0.927, −0.934, P<0.05), and the change rate of false lumen diameter was negatively correlated with the follow-up time (−0.774, −0.935, −0.952, P<0.05). When the unstented segment of the abdominal aorta was evaluated (L₄-L₅), the average true lumen diameter at the level of celiac trunk increased significantly at 1 year by 13.7% (P=0.007), however, the average false lumen diameter did not change over time (P=0.406). The average true lumen diameter and false lumen diameter at the level of the lowest renal arteries increased over time as well, the average true lumen increased by 10.1%, and the average false lumen increased by 13.6% (P=0.048, 0.017). Besides, the complete false lumen thrombosis rate of the stented segment of the descending thoracic aorta was higher than that of the unstented segment of the abdominal aorta.e complete false lumen thrombosis rate of the stented segment of the descending thoracic aorta was higher than that of the unstented segment of the abdominal aorta.

  Conclusion  After receiving TEVAR-TSI, Stanford type B aortic dissection patients had high thrombosis absorption rate in the thoracic aortic segment covered by stent, and the aortic remodeling was more ideal. The aortic remodeling effect in the abdominal aortic segment not covered was not ideal, and the inner diameter of the abdominal aorta tended to increase. Therefore, close follow-up monitoring should be conducted.