Left Subclavian Artery Revascularization in Aortic Arch Replacement: Comparative Patency of In Situ Reconstruction and Extra-Anatomic Bypass

OBJECTIVES: Revascularization of the left subclavian artery (LSCA) is routinely required during total aortic arch replacement. In situ reconstruction may be technically difficult in cases with large aneurysms or posterior vessel displacement. Extra-anatomic aorto-axillary bypass has been proposed as an alternative, but its long-term patency relative to in situ repair remains uncertain. This study compared LSCA patency between the 2 techniques. METHODS: We retrospectively analysed 436 consecutive patients (median age 69.0 years [interquartile range (IQR) 62.0-75.0]; 347 men) who underwent total arch replacement with LSCA revascularization: 240 in situ and 196 extra-anatomic. Postoperative CT imaging (1853 scans; median 3 [IQR 1-6] per patient) was reviewed to determine immediate and long-term patency. Kaplan-Meier analysis was used for time-to-event comparison. A small descriptive subgroup of 18 patients undergoing concomitant left internal thoracic artery (LITA) to left anterior descending artery (LAD) bypass was also reviewed. RESULTS: Perioperative outcomes, including mortality and major complications, were similar between groups. Subclavian wound infection occurred in 3 extra-anatomic cases (1.5%), all managed successfully with local care. Immediate LSCA patency was higher after extra-anatomic bypass (100% vs 92.9%, P < .001). At 5 years, patency remained superior with extra-anatomic bypass (97.7% vs 87.8%; log-rank P = .0002). In the descriptive LITA-LAD subgroup, CT follow-up demonstrated 100% LSCA and LITA graft patency; however, interpretation is limited by the small sample size. CONCLUSIONS: Compared with in situ reconstruction, extra-anatomic LSCA bypass provides equivalent perioperative safety and superior long-term patency. These findings support extra-anatomic bypass as a reliable and technically straightforward option for LSCA revascularization during total arch replacement.