True lumen expansion but no aortic remodeling following thoracic endografting and distal bare stent for subacute complicated type B aortic dissection

Background: The effects of thoracic endovascular aneurysm repair (TEVAR) with additional distal bare metal stents (BMSs) in patients with subacute complicated type B aortic dissection (cTBAD) are unclear and are investigated in this retrospective study. Methods: The medical records of 67 patients who received TEVAR due to subacute cTBAD were reviewed. Areas of true lumen (TL) and false lumen at five levels-pulmonary artery (PA), diaphragm, renal artery (RA), middle of the infrarenal aorta, and aortic bifurcation-were measured using computed tomography before and 3, 6, and 12 months after surgery. The TL ratio (TL area/total aortic area) and total aortic area at each time point were compared between the TEVAR + BMS (n = 37) and TEVAR-only (n = 30) groups. The effects of BMS use and time were evaluated using generalized estimating equations and generalized linear regression models. Results: Baseline characteristics, remodeling types, and clinical outcomes did not differ significantly between the two groups. Postoperative TL ratios at the diaphragm and RA were significantly higher in the TEVAR + BMS group than in the TEVAR-only group (p < 0.05). BMS use and time had significant interaction effects at the PA, diaphragm, and RA (all p < 0.05), but effects on total aortic area were not significant at any of the five parts. TL ratios at the diaphragm and RA exhibited greater improvement in the TEVAR + BMS group than in the TEVAR-only group at postoperative months 6 and 12 (all p < 0.001). Aortic diameters at all five parts were significantly smaller in the TEVAR + BMS group than in the TEVAR-only group (all p < 0.05). Conclusion: In patients with subacute cTBAD, TEVAR with BMS implantation effectively expands the TL from the thoracic aorta to the RA but neither enhances aortic remodeling nor elicits any change in total aortic area in whole dissected aorta relative to TEVAR only.