Proximal Bare Stent May Reduce Bird-Beak Configuration, Which is Associated with Distal Migration of Stent Graft in the Aortic Arch.

BACKGROUND

Prior studies have shown that a bird-beak configuration causes serious complications after thoracic endovascular aortic repair (TEVAR). However, factors that cause bird-beak configurations are poorly understood. The purpose of this study was to assess the influences of anatomical and device-related factors on bird-beak configuration.

METHODS

Sixty-eight consecutive patients (47 men, mean age, 72.8 ± 9.8 years) who underwent TEVAR with proximal fixation in zones 1 to 3 from March 2009 to February 2017 were included. Preoperative and postoperative computed tomography (CT) scans were retrospectively reviewed. Relationships between the incidence of a bird-beak configuration, preoperative aortic arch morphology, and type of stent graft were estimated. The influence of a bird-beak configuration on endograft migration over time was also estimated for 47 patients who underwent CT 12 months after TEVAR.

RESULTS

The patients' aortic arch pathologies included 52 aneurysms, 11 aortic dissections, 4 pseudoaneurysms, and 1 patent ductus arteriosus. Stent grafts with (the proximal bare stent group [PBS group]) and without (the nonbare stent group [NBS group]) a proximal bare stent were implanted in 24 and 44 patients, respectively. A bird-beak configuration was detected in 30 patients (mean length ± standard deviation [SD], 6.2 ± 3.4 mm; mean angle ± SD, 31.7 ± 14.7°) and was significantly more frequent in the NBS group (n = 29) than in the PBS group (n = 1) (P < 0.001). Proximal landing zone, aortic lengths, and aortic arch morphology, including the radius, tortuosity, and angulation of aortic arch curvature, were not associated with the bird-beak configuration. The migration distance after 1 year was significantly longer in patients with a bird-beak configuration (3.5 ± 6.1 mm) than in patients without a bird-beak configuration (0.5 ± 1.0 mm) (P = 0.015).

CONCLUSION

This study demonstrated that in aortic arch TEVAR, the use of stent graft with a proximal bare stent may reduce bird-beak configuration, which is associated with distal migration of the stent graft during follow-up.