Utility of Single-Branched Thoracic Endograft in Patients Requiring Zone 2 Seal During Thoracic Endovascular Aortic Repair

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Single-branched thoracic endografts (SBTEs) are under investigation for treatment of thoracic aortic disease that requires zone 2 seal during thoracic endovascular aortic repair (TEVAR). A variety of anatomic criteria must be met for their effective implantation. Our aim was to analyze anatomic suitability for SBTE. We performed a retrospective review of 103 TEVAR procedures in 88 patients at our academic referral center between 2017 and 2019. Proximal seal was achieved in zone 3 or zone 4 (n = 37 [36%]), zone 2 (n = 30 [29%]), or zone 0 or zone 1 (n = 36 [35%]). We analyzed the zone 2 group’s operative angiograms and preoperative computed tomography angiograms using centerline software to measure arterial diameters and length in relation to the left common carotid artery, left subclavian artery (LSA), and proximal extent of aortic disease to determine whether patients met anatomic criteria using the instructions for use (IFU) of the Navion Mona LSA (Medtronic, Santa Rosa, Calif; Table I). Average age in the zone 2 group was 64 years (range, 26-85 years); 17 were male (57%). Indications (Table II) were acute type B dissection (ATBD; n = 13 [43%]), aneurysm (n = 15 [50%]), and blunt aortic injury (n = 2 [7%]). The LSA was revascularized in 20 (67%): carotid subclavian bypass or transposition, n = 17; laser fenestration, n = 3. Overall, 14 (47%) of the zone 2 patients met the IFU. Reasons for failure are listed in Table I. Of the 16 who did not meet IFU, 9 had multiple exclusion criteria. Inadequate aortic diameter excluded only the two blunt aortic injury patients. The proportion of patients who met IFU criteria by indication are listed in Table II. Fewer ATBDs (5/13 [38%]) met IFU than aneurysms (9/15 [60%]), but this was not statistically significant (P = .26). Of the eight ATBD patients who failed to meet criteria, seven had dissection at or into the origin of the LSA. If dissection into the LSA origin was allowed in ATBD, three of the seven would have otherwise qualified. Approximately half of patients who require TEVAR seal in zone 2 meet criteria for this SBTE. The device may offer the ability to provide flow to the LSA without the need for adjuvant revascularization procedures. Patients with aneurysms more often met the IFU than those with acute dissection. A modification to the IFU to allow dissection up to the LSA origin would increase eligibility in ATBD by >50%. Clinical efficacy data, however, are needed to determine whether this would be effective.Table IAnatomic criteria for the Navion Mona LSAAnatomic criteriaCriteria to meet IFUMean ± SD, mmNo. (%) failing to meet criteriaAortic diameter at proximal seal zoneDissection: 28-44 mm Aneurysm/PAU: 25-42 mm30.2 ± 3.82 (7)LSA diameter8-13 mm9.47 ± 1.30 (0)Distance between orifices of LCCA to LSA≥10 mm10.9 ± 6.012 (40)Distance of LCCA to aortic disease≥20 mm22.1 ± 10.111 (37)Distance of LSA to aortic disease≥0 mm (presence of nondiseased aorta distal to LSA)5.6 ± 6.311 (37)IFU, Instructions for use; LCCA, left common carotid artery; LSA, left subclavian artery; PAU, penetrating aortic ulcer; SD, standard deviation. Open table in a new tab Table IIThoracic endovascular aortic repair (TEVAR) indications and proportion that met the instructions for use (IFU)IndicationNo.No. (%) meeting criteriaAcute type B dissection135 (38)Aneurysm or penetrating ulcer96 (67)Aneurysm in chronic dissection63 (50)Blunt aortic injury20 (0) Open table in a new tab