Holding on to bypass in endovascular times? A narrative review on the role of surgical LSA revascularization in zone 2 TEVAR and how to achieve optimal results

Thoracic endovascular aortic repair (TEVAR) has become the preferred treatment for most descending thoracic aortic pathologies. In Zone 2 procedures, intentional coverage of the left subclavian artery (LSA) is frequently required to achieve an adequate proximal seal, but this carries a risk of stroke, spinal cord ischemia, and upper extremity ischemia. Preventive LSA revascularization is therefore recommended in current guidelines, although the level of supporting evidence remains limited. This narrative review summarizes the indications, timing strategies, techniques, and outcomes of surgical LSA debranching in combination with Zone 2 TEVAR. Both carotid-subclavian bypass (CSB) and subclavian-carotid transposition (SCT) restore antegrade flow to the LSA. Patency rates are excellent for both techniques, with CSB being favored in many tertiary centers due to lower rates of local nerve injury. Timing remains debated: staged approaches are increasingly adopted in elective cases, as simultaneous debranching and TEVAR have been associated with higher perioperative stroke rates. However, overall stroke risk appears more strongly related to the TEVAR procedure itself than to the revascularization technique. Surgical debranching offers long-term durability and versatility, especially in complex arch anatomy, and avoids endoleak-related complications. Endovascular alternatives, however, reduce local surgical morbidity and allow minimally invasive management under sedation, with comparable long-term survival. In conclusion, surgical LSA debranching remains a cornerstone adjunct to Zone 2 TEVAR, balancing durability and neurological protection against higher local complication rates. Further studies are required to refine patient selection, compare surgical and endovascular strategies, and strengthen the evidence base for current recommendations.