title: Aortoiliac angulation and the need for secondary procedures to secure stent graft fixation: which angle is important?
abstract: BACKGROUND
  The purpose of this study was to quantify the degree of aortoiliac tortuosity and determine the relationship between aortoiliac angulation and the need for a secondary procedure following endovascular repair.
  
  
  METHODS
  Among 206 patients treated with the AneuRx stent graft, 3-year follow up data were available in 71 patients. Twenty eight patients without duplex and CT angiograms (CT angiography) on follow-up were excluded. The anatomy of the preoperative proximal aortic neck was evaluated using 3D-CT angiography reconstructed images in: a) Group I: 15 patients who required secondary procedures and b) Group II: 18 patients without any endovascular leak during follow up. The groups did not differ in age (72.9+/-6.1 versus 73.3+/-9.1) or aneurysm diameter (60.1+/-9.1 versus 60.5+/-10.1). In order to determine the aortoiliac tortuosity, we measured: a) the suprarenal aorta-infrarenal aortic neck angle: angle of the aorta at the level of the renal arteries, b) infrarenal aortic neck-aneurysm angle: angle of the aorta at the start of aneurysm, c) right iliac angle, d) left iliac angle, e) aortic neck length, f) aortic neck diameter.
  
  
  RESULTS
  Computer-based measurements on 3D-CT angiography reconstructed images were: a) suprarenal aorta-infrarenal aortic neck angle: group I: (22.6+/-16.2), group II: (11.9+/-6.9), p<0.05; b) infrarenal aortic neck-aneurysm angle: group I: 17.6+/-12.4, group II: 18.8+/-9.4, p=NS; c) right iliac angle: group I: 22.9+/-12.6, group II: 20.4+/-9.5, p=NS; d) left iliac angle: group I: 22.4+/-10.5, group II: 19.1+/-12.2, p=NS; e) aortic neck length: group I: 18.9+/-5.3 mm, group II: 20.4+/-5.3 mm, p=NS; f) aortic neck diameter: group I: 24.1+/-1.0 mm, group II: 23.3+/-1.6, p=NS.
  
  
  CONCLUSIONS
  Aortoiliac angulation can be defined and quantified. In patients requiring secondary procedures, there is an increased angulation at the proximal aortic neck angle.
authors.affiliation: Division of Vascular Surgery, Stanford University Hospital, CA, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Filis
authors.forename: F R
authors.initials: FR
authors.lastname: Arko
authors.forename: G D
authors.initials: GD
authors.lastname: Rubin
authors.forename: B
authors.initials: B
authors.lastname: Raman
authors.forename: T J
authors.initials: TJ
authors.lastname: Fogarty
authors.forename: C K
authors.initials: CK
authors.lastname: Zarins
mesh_terms: D000368:Aged; D001011:Aorta / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography; D019917:Blood Vessel Prosthesis Implantation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011475:Prosthesis Failure; D012086:Reoperation; D015607:Stents; D013997:Time Factors; D036542:Tomography, Spiral Computed; D019415:Torque