Outcomes of Zone 2 vs. Zone 3 Distal Anastomosis in Frozen Elephant Trunk Repair for Acute Type A Aortic Dissection: Insights from a Single Aortic Center Experience

All articles of this category (opens in new window) Background: Proximalization of the distal anastomosis to Zone 2, with extra-anatomic bypass to the left subclavian artery (LSA), in the Frozen Elephant Trunk (FET) procedure, has gained increasing adoption due to its potential to simplify the surgical technique and reduce perioperative morbidity. Concerns persist about early bypass occlusion and higher aortic reintervention rates. This study aims to evaluate short- and mid-term outcomes in patients undergoing FET for acute type A aortic dissection (ATAAD), comparing distal anastomosis performed in Zone 2 vs. Zone 3. Methods: Data from patients who underwent surgical repair for ATAAD using the FET technique between 2019 and 2025 were analyzed. Patients were categorized based on the location of the distal anastomosis: Group A (Zone 2) and Group B (Zone 3). Characteristics and outcomes were compared. Patency of LSA was assessed on CT imaging. Results: A total of 53 patients underwent FET repair for ATAAD during the study period: 24 patients (45.3%) in Group A and 29 patients (54.7%) in Group B. Baseline characteristics, including the GERAADA score, were comparable between groups (18.9 ± 9 vs. 23.06 ± 14; p = 0.204). Group A demonstrated significantly shorter cross-clamp time (134 ± 66 vs. 162 ± 41 minutes; p = 0.023) and visceral ischemia time (60 ± 14 vs. 76 ± 18 minutes; p = 0.01). The type of root repair was similar. Group A demonstrated a trend toward lower rates of revision for bleeding (12.5% vs. 24.1%; p = 0.23), acute kidney injury requiring dialysis (16.7% vs. 31.0%; p = 0.18), and organ malperfusion (20.8% vs. 41.4%; p = 0.096). Similarly, both in-hospital mortality (8.3% vs. 21.4%; p = 0.195) and 1-year mortality rates (0% vs. 4.3%; p = 0.111) were lower in Group A compared to Group B, although these differences did not reach statistical significance. At 23 months follow-up, CT imaging revealed asymptomatic stenosis of the extra-anatomic bypass in two patients (8.7%) in Group A. In Group B, occlusion of the subclavian artery was observed in one patient (5.9%). The need for thoracic endovascular aortic repair (TEVAR) showed a higher tendency in Group A (33% vs. 10.5%; p = 0.099). Conclusion: Distal anastomosis performed in Zone 3 during FET repair for acute type A aortic dissection appears to be associated with higher perioperative morbidity and mortality. Patency of the extra-anatomic bypass to LSA appears satisfactory. However, patients with Zone 2 anastomosis may have an increased need for TEVAR. Larger, multicenter studies are warranted to further delineate the advantages and disadvantages of each surgical strategy. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany