Geometrical Evaluation of Aortic Sac Remodeling During Two-Step Thoracoabdominal Aortic Aneurysm Endovascular Repair

Background: The present study evaluates aneurysmal sac remodeling and the loss of the intercostal arteries after the first step of staged treatment of thoracoabdominal aortic aneurysms (TAAAs). The purpose of this approach is to keep the aneurysmal sac temporarily perfused to induce progressive thrombosis of the aneurysm while simultaneously allowing the spinal cord to establish adequate perfusion thereby promoting the development of collateral circulation. Methods: All patients with type II or type III TAAAs, having undergone 2-step endovascular treatment with at least a 2-branch endoprosthesis at our institution between April 2017 and May 2019, were retrospectively evaluated. Thirty-day mortality and spinal cord ischemia was assessed. The mean number of the intercostal and lumbar arteries, coverage length between the left subclavian artery and the stent graft proximal landing zone, total volume of the aneurysmal sac, lumen volume, and thrombosis volume were measured by preoperative and first-step postoperative computed tomography angiography. Patients were also grouped based on the chosen endoprosthesis (group A: double-branch aneurysmal sac reperfusion; group B: single-branch aneurysmal sac reperfusion). Results: Eleven patients (mean age: 76.5 years; range: 61–86) were considered. No 30-day mortality was observed after the first-step procedure, and 1 patient died after second-step treatment. No permanent paraplegia was observed after either the first or second endovascular steps. The lumen volume significantly decreased (27%; P < 0.001) after first-step endovascular treatment although there was a significant increase in aneurysm thrombosis (34% to 54%). The mean number of the intercostal arteries decreased from 19.7 to 9.3 (P < 0.001) after first-step endovascular treatment. Volume variations and percentage of intercostal loss did not significantly differ between the 2 groups. Conclusions: Although aneurysm volume continued to increase after first-step treatment, two-step endovascular treatment is a feasible alternative to reduce the risk of severe ischemia in patients with extended TAAAs.