(PC016) Outcomes of On-label Versus Off-label Use of a Single Retrograde Thoracic Branch Endoprosthesis in Thoracic Endovascular Aortic Repair (TEVAR)

Objectives: The thoracic branch endoprosthesis (TBE®, WL Gore, Flagstaff AZ) is the first commercially approved off-the-shelf device for zone 2 TEVAR with an inner branch for the left subclavian artery. While trial results within instructions for use (IFU) are excellent, overall suitability is limited by strict anatomic requirements. In urgent settings, this limitation can be overcome by off-label application of TBE. We sought to describe on and off-label use and compare clinical outcomes.

Methods: Consecutive patients who underwent TBE implantations across all aortic arch zones at two centers between January, 2017 to July, 2024 were retrospectively reviewed. Off-label usage was described based on 3-dimensional multiplanar analysis of pre and post-implant CT images. Baseline patient characteristics, underlying aortic pathologies, and outcomes were compared between the on vs off-label groups. Primary outcomes included technical success, mortality, major adverse events (MAE) (access site complication requiring reintervention, stroke, death, heart attack, pneumonia, paraplegia, retrograde dissection) at 30-days. Secondary were branch patency and reinterventions during follow-up.

Results: Of 146 patients in the study, 29 (20%) patients received TBE outside IFU. Reasons for off-label usage included zone 0 and 1 deployment (13 patients, nine zone 0, four zone 1), distal deployment of TBE due to insufficient distance between the left carotid and left subclavian (7 patients, median 14.9 mm, IQR 12.9-17), or incorporation of aberrant right subclavian artery (2 patients). Among off-label zone 2 repairs, sandwich periscope TBE technique was used in 12 patients. Type B aortic dissection (TBAD) was the most frequent indication for off-label repair and 100% of repairs were on-label for blunt thoracic aortic injuries (BTAI) (Table 1).

Technical success was high (97%) in both groups. At 30-days, one (1%) mortality was seen in the off-label group. MAE occurred at similar rate (14% vs 13%, p= .800). (Table 2) One on-label patient (1%; Zone 2 repair) had a retrograde aortic dissection, managed with open repair. The sidebranch remained patent in 130 patients with follow up imaging, with 10% reintervention rate (14 patients total; 6 patients 21% off-label, 4 patients Zone 2; 8 patients 7% on-label, p=.028)

Conclusions: Off-label TBE can facilitate TEVAR in the aortic arch and aberrant anatomy. We observed no significant difference in MAE or branch patency between on and off-label usage, though reinterventions are more common. Long term data is needed to confirm these initial outcomes.