Chimney Technique and Single-Branched Stent Graft for the Left Subclavian Artery Preservation During Zone 2 Thoracic Endovascular Aortic Repair for Type B Acute Aortic Syndromes

Purpose: The purpose of this study was to evaluate the efficacy and safety of zone 2 thoracic endovascular aortic repair assisted by the chimney technique or single-branched stent graft for the preservation of the left subclavian artery, and summarize our single-center experience with the techniques. Materials and methods: From February 2017 to June 2020, 137 patients who underwent left subclavian artery revascularization during zone 2 thoracic endovascular aortic repair were enrolled. Patients had acute type B aortic dissection and penetrating aortic ulcer associated with intramural hematoma. The chimney technique was performed in 68 patients (group A), and single-branched stent graft was deployed in 69 patients (group B). All procedures were performed during the acute phase. Primary technical success, immediate postoperative endoleak, neurologic complications (stroke or spinal cord ischemia), 30-day mortality, 1-year technical success, all-cause mortality, patency of the left subclavian artery, and reintervention were analyzed. Comparing the occurrence of the Bird-Beak Configuration, defined as a gap between the aortic wall and the sent graft with stent protrusion into the aortic lumen more than 5 mm, was also performed. Results: Primary technique success was achieved in 66 and 67 patients in groups A and B, respectively. The incidence of immediate postoperative endoleak, neurologic complications (stroke or spinal cord ischemia), and 30-day mortality were 5.9%, 1.5%, and 4.4% in group A, and 2.9%, 2.9%, and 2.9% in group B, respectively. During follow-up, the 1-year technical success rate was similar in both groups. All-cause mortality was similar in both groups (3.1% in group A and 4.5% in group B). The patency of the left subclavian artery was not significantly different between the 2 groups with 2 and 3 occlusions in groups A and B, respectively. The rate of reintervention was higher in group B (3.1% vs 1.6%, p=0.536), with a non-significant difference. Bird-Beak Configuration was more prominent in group B with the incidence of 59.42%. Conclusions: Acting as minimally invasive alternatives, both techniques are feasible for left subclavian artery preservation during zone 2 thoracic endovascular aortic repair for type B acute aortic syndromes with encouraging mid-term outcomes. Long-term follow-up is required to confirm these findings.