title: Incomplete endograft apposition to the aortic arch: bird-beak configuration increases risk of endoleak formation after thoracic endovascular aortic repair.
abstract: OBJECTIVE
  To determine the clinical importance of the bird-beak configuration after thoracic endovascular aortic repair (TEVAR).
  
  
  METHODS
  The institutional review board approved this retrospective study and waived the requirement to obtain informed consent from patients. Sixty-four patients (40 men, 24 women; mean age, 64 years) who underwent TEVAR were evaluated. The treated diseases included dissection (n = 29), degenerative aneurysm (n = 13), acute traumatic transection (n = 8), pseudoaneurysm (n = 4), penetrating aortic ulcer (n = 6), intramural hematoma (n = 2), and mycotic aneurysm (n = 2). Bird-beak configuration, defined as the incomplete apposition of the proximal endograft with a wedge-shaped gap between the device and the aortic wall, was assessed with postprocedural CT angiography. The presence and length of the bird-beak configuration were compared with the formation of endoleaks and adverse clinical events.
  
  
  RESULTS
  Endoleaks were detected in 26 (40%) of the 64 patients, including 14 with type Ia endoleak formation, one with type Ib endoleak formation, six with type II endoleak formation (from the left subclavian artery), two with type IIo endoleak formation (from other arteries), and three with type III endoleak formation. Bird-beak configuration was observed in 28 (44%) of 64 patients and correlated significantly with the risk of developing a type Ia or IIa endoleak (P < .01). Mean bird-beak length was significantly longer (P < .01) in patients with a type Ia or II endoleak (mean length, 14.3 and 13.9 mm, respectively) than in patients without endoleaks (mean length, 8.4 mm). Adverse events included early aortic-related death in three patients, additional treatment for endoleak in eight patients, and stent-graft collapse or infolding in six patients.
  
  
  CONCLUSIONS
  Detection of bird-beak configuration is helpful in the prediction of adverse clinical events after TEVAR.
authors.affiliation: Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, Room S-072, Stanford, CA 94305, USA. takueda-rad@umin.ac.jp
authors.forename: Takuya
authors.initials: T
authors.lastname: Ueda
authors.forename: Dominik
authors.initials: D
authors.lastname: Fleischmann
authors.forename: Michael D
authors.initials: MD
authors.lastname: Dake
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Rubin
authors.forename: Daniel Y
authors.initials: DY
authors.lastname: Sze
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D001013:Aorta, Thoracic / Q000601:surgery*; D001018:Aortic Diseases / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011475:Prosthesis Failure; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media