Carotid-Axillary Bypass as an Alternative to Carotid-Subclavian Bypass Following Coverage of Left Subclavian Artery During TEVAR

Introduction: Thoracic Endovascular Aortic Repair (TEVAR) has become the procedure of choice for pathology involving the descending thoracic aorta since its approval by the FDA in 2005. Left subclavian artery (LSA) coverage is commonly required to facilitate an adequate proximal landing zone for the endograft. The traditional revascularization procedure of choice is carotid-subclavian bypass, however recent studies report complication rates as high as 29%—specifically phrenic nerve palsy in 25% of patients undergoing this procedure. Our aim is to present our experience using carotid-axillary bypass as a safe alternative to carotid-subclavian bypass. Methods: All patients undergoing carotid-axillary bypass for TEVAR with LSA coverage between June 2016 and September 2019 at a tertiary medical center were retrospectively identified. Short-term and long-term complications were identified and analyzed including: phrenic nerve, recurrent laryngeal nerve, and axillary nerve injuries, as well as local vascular complications requiring re-intervention. All perioperative chest radiographs were reviewed for new hemidiaphragm elevation to assess for phrenic nerve injuries. Results: 35 patients underwent carotid-axillary bypass in conjunction with TEVAR during this time period. The majority of bypasses were performed concurrently with TEVAR (80.0%, 28/35) utilizing GORE PROPATEN 8 mm externally supported vascular graft (91.4%, 32/35). The complication rate specific to carotid-axillary bypass was 14.3% (5/35). We observed a significantly lower (0%, 0/35, P < 0.01) rate of phrenic nerve palsy for carotid-axillary bypass compared to the previously reported 25% (27/107) for carotid-subclavian bypass. For patients with available follow-up imaging (85.7%, 30/35), there was a 100% patency rate at time intervals ranging from 0-1066 days (IQR = 3-37.8). Conclusion: Carotid-axillary bypass can be performed as a safe alternative to carotid-subclavian bypass for LSA coverage during TEVAR involving a more superficial anatomic course of dissection. Phrenic nerve palsy, a well-described complication of the traditional carotid-subclavian bypass, was not observed in this retrospective series.