title: Aortic neck morphology after endovascular repair of descending thoracic aortic aneurysms.
abstract: BACKGROUND
  Endovascular repair has emerged as a less-invasive treatment for descending thoracic aortic (DTA) aneurysms. However, the durability of this procedure relies on the stability of proximal and distal fixation sites. This study analyzes 3 years of computed tomography (CT) data on aortic neck morphology after endovascular DTA aneurysm repair.
  
  
  METHODS
  Between 1999 and 2001, 139 patients underwent successful endovascular DTA repair as part of a prospective, multicenter clinical trial investigating the Gore TAG thoracic endoprosthesis. Contrast-enhanced, high-resolution CT scans were obtained at 1 (baseline), 12, 24, and 36 months and submitted to an independent core laboratory for image analysis. The aorta was carefully measured by using computerized planimetry and a standardized protocol. Neck diameter was measured at 10-mm intervals for 2 cm above and below the aneurysm and correlated with graft migration and endoleak.
  
  
  RESULTS
  The mean proximal neck diameter increased from a baseline of 30.2 +/- 4.6 mm to 32.0 +/- 4.3 mm at 36 months (P <.05), and the annual diameter increase was 0.8, 0.4, and 0.6 mm at 12, 24, and 36 months. The mean distal neck diameter increased from 29.4 +/- 3.8 mm to 32.1 +/- 5.0 mm at 36 months (P <.05), and the annual diameter increase was 1.1, 0.4, and 1.2 mm at 12, 24, and 36 months. At 36 months, freedom from neck dilation of > or =5 mm was 87%, and freedom from migration of > or =10 mm was 83%. An endoleak was present in 11 (9%) of 122 patients at baseline, 7 (7%) of 96 at 12 months, 6 (9%) of 68 at 24 months, and 1 (3%) of 33 at 36 months. Neck dilation was not associated with graft migration or endoleak.
  
  
  CONCLUSIONS
  Three years after endovascular repair of DTA aneurysms, there is progressive enlargement of the proximal and distal aortic necks. Although uncommon for patients to develop significant neck dilation, when it does occur, it is not associated with graft migration or endoleak. Continued surveillance of aortic neck morphology after descending thoracic aneurysm endografting is recommended.
authors.affiliation: Department of Surgery, Division of Vascular Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
authors.forename: Heitham T
authors.initials: HT
authors.lastname: Hassoun
authors.forename: R Scott
authors.initials: RS
authors.lastname: Mitchell
authors.forename: Michel S
authors.initials: MS
authors.lastname: Makaroun
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Whiting
authors.forename: Kelley R
authors.initials: KR
authors.lastname: Cardeira
authors.forename: Jon S
authors.initials: JS
authors.lastname: Matsumura
mesh_terms: D001013:Aorta, Thoracic / Q000000981:diagnostic imaging*; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D006801:Humans; D011446:Prospective Studies; D011859:Radiography