Outcomes of carotid-subclavian bypass performed in the setting of thoracic endovascular aortic repair.

Background: Subclavian artery revascularization is frequently performed in the setting of thoracic endovascular aortic repair (TEVAR). However, there is little information on the short- and long-term outcomes of patients undergoing carotid to subclavian artery bypass in this clinical setting. As such, this study sought to define the early and late outcomes associated with this procedure.

Methods: Patients undergoing carotid-subclavian bypass in conjunction with TEVAR between June 2005 and September 2016 were retrospectively identified from a prospectively maintained, single-center aortic surgery database. The 30-day outcomes specific to the carotid-subclavian bypass procedure were analyzed, including cervical plexus nerve injury, bleeding complications, and local vascular complications. All preoperative and postoperative chest radiographs were carefully analyzed to assess for hemidiaphragm elevation indicative of phrenic nerve palsy. Long-term outcomes included primary graft patency and anastomotic complications.

Results: Of 579 consecutive patients undergoing TEVAR during this time interval, 112 patients (19%) underwent concomitant carotid-subclavian bypass. The cohort was 38% female (n = 43), with a mean age of 65 ± 14 years. The majority of conduits were 8-mm polytetrafluoroethylene grafts (n = 107 [95.5%]), with a minority being reversed saphenous vein (n = 4 [3.6%]) or Dacron (n = 1 [0.9%]) grafts. The bypass procedure was done concurrently at the time of TEVAR in 91% (n = 102) of cases. The short-term complication rate attributed specifically to the carotid-subclavian bypass was 29% (n = 33). These complications included phrenic nerve palsy in 25% (n = 27), recurrent laryngeal nerve palsy in 5% (n = 6), axillary nerve palsy in 2% (n = 2), and neck hematoma requiring re-exploration in 1% (n = 1) of patients. The 30-day in-hospital all-cause mortality rate was 5% (n = 6), and the rate of permanent paraparesis or paraplegia was 0.9% (n = 1). Of the operative survivors (n = 106), follow-up imaging of the bypass graft was available in 87% (n = 92) of patients. Actuarial primary graft patency was 97% at 5 years. There were three patients (3%) with bypass graft occlusions, two of which were clinically silent and detected on follow-up imaging. The third was detected because of symptoms of subclavian steal and required repeated revascularization. Two patients (2%) developed a late anastomotic pseudoaneurysm requiring either endovascular (n = 1) or surgical (n = 1) intervention.

Conclusions: Carotid-subclavian bypass for revascularization of the subclavian artery performed in the setting of TEVAR is durable, although the true complication rate is likely higher than is generally reported in the literature because of a not insignificant rate of phrenic nerve palsy. These data should serve well as "gold standard" comparison data for emerging branch graft devices.