title: Morphologic changes and outcome following endovascular abdominal aortic aneurysm repair as a function of aneurysm size.
abstract: OBJECTIVE
  Small infrarenal abdominal aortic aneurysms have a more favorable clinical and morphologic outcome compared with medium and large abdominal aortic aneurysms following endovascular aneurysm repair(EVAR).
  
  
  METHODS
  A prospective clinical series of 206 patients undergoing elective EVAR between 1996 and 2001.
  
  
  METHODS
  A tertiary care academic health center.
  
  
  METHODS
  Patients were grouped according to aneurysm size: small (<50 mm), medium (50-60 mm), and large (>60 mm).
  
  
  METHODS
  Primary EVAR and secondary procedures to secure fixation of the stent graft and surgical conversions.
  
  
  METHODS
  Aneurysm diameter, endoleaks, and long-term morphologic changes were analyzed postoperatively with 3-dimensional reconstructions of computed tomographic angiograms.
  
  
  RESULTS
  Groups were similar in age, comorbidities, and follow-up (mean +/- SD, 32.1 +/- 11.8 months). There were 30 small aneurysms, 92 medium aneurysms, and 84 large aneurysms, with a mean size of 45.1 +/- 3.7 mm, 53.8 +/- 3.1 mm, and 66.1 +/- 6.8 mm, respectively (P<.01). There was no significant difference in proximal neck or iliac artery diameter among the 3 groups. The proximal aortic neck length (28.1 +/- 11.6 mm [small]; 23.9 +/- 11.3 mm [medium]; and 22.1 +/- 11.6 mm [large]; P<.05) was significantly shorter in large aneurysms. Furthermore, there was a significant increase (6% [small]; 15% [medium]; and 21% [large]; P<.05) in angulated necks in large aneurysms. Following treatment, aneurysm diameter remained stable in most patients (83% [small]; 82% [medium]; and 83% [large]), with a mean decrease of 2.0 +/- 6.5 mm, 2.1 +/- 6.1 mm, and 3.7 +/- 7.7 mm in each group, respectively (P =.45). There was no difference in the incidence of endoleaks, aneurysm contraction, or aneurysm expansion based on preoperative aneurysm diameter. Secondary procedures were performed in 5 (20%) of 25, 9 (5.2%) of 170, and 5 (36%) of 11 aneurysms that contracted, remained stable, or expanded, respectively, following EVAR (P<.05).
  
  
  CONCLUSIONS
  There is a 15% increase in neck angulation and a 27% decrease in neck length in large compared with small infrarenal abdominal aortic aneurysms, with no difference in outcome. Aneurysms that are stable following EVAR have a significantly lower incidence of requiring secondary procedures.
authors.affiliation: Division of Vascular Surgery, Department of Surgery, Stanford University, Stanford, Calif., USA. farko@stanford.edu
authors.forename: Frank R
authors.initials: FR
authors.lastname: Arko
authors.forename: Konstantinos A
authors.initials: KA
authors.lastname: Filis
authors.forename: Bradley B
authors.initials: BB
authors.lastname: Hill
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Fogarty
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Zarins
mesh_terms: D000368:Aged; D017130:Angioplasty; D017544:Aortic Aneurysm, Abdominal / Q000503:physiopathology* / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D001837:Body Weights and Measures; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome