BS2. High Angulation and Short Neck Length Do Not Impact AAA Sac Expansion After Repair Using the Lombard Aorfix Device

Abstract

Angulated (≥60°) infrarenal aortic necks and short neck lengths, are associated with sac expansion following EVAR. Aorfix (Lombard Medical), a conformable stent graft designed for highly angulated necks, was investigated in the U.S. Pythagoras Trial. We hypothesized that sac expansion may be independent of neck angle and length after AAA repair with Aorfix grafts. Trial data were assessed with mutivariable modeling for factors associated with sac regression/expansion (R/E), defined as change in maximum aneurysm diameter of ≥5 mm on annual follow-up computed tomography (CT) compared with the last preoperative scan). Sac expansion after Aorfix implantation was compared in “standard angle” (<60°) and “high angle” (≥60°) proximal necks. Neck length measurements were performed per protocol by a core laboratory, M2S. A total of 210 patients with implants were followed up ≥30 days; neck angle was ≥60° in 151 (71.9%), < 60° in 59 (28.1%). Mean neck length was 23.1 mm. Follow-up, including CT imaging, was available at 1 year (n = 165), 2 years (n = 142), 3 years (n = 106), and 4 years (n = 70). Sac size decreased or was unchanged in 98.8% (1 year), 95.1% (2 years), 94.3% (3 years), and 92.9% (4 years; Fig 1). Factors associated with sac regression at 4 years include less calcified plaque in the proximal aortic neck (odds ratio [OR] 3.84; P = .02) and iliac arteries (OR, 3.36; P = .04), and length of neck apposition (OR, 2.21; P = .04). Longer distance from lowest renal artery to proximal graft was associated with sac expansion at 4 years (OR, 1.89; P = .001). Sac R/E was not related to neck length, neck diameter, internal iliac artery patency, maximal aneurysm diameter, patient age or gender, and nine other demographic variables (P > .05 for all). Absence of endoleak was associated with sac regression at 1 and 2 years (OR, 5.98; P = .02; OR, 17.6; P < .001) but not at 3 and 4 years (P > .05). Neck angle was not associated with sac R/E (P > .45 all timepoints). In distinction from previous reports, increased neck angulation and neck length do not predict sac R/E with Aorfix grafts.