title: Disparate outcome after endovascular treatment of small versus large abdominal aortic aneurysm.
abstract: OBJECTIVE
  The size of an abdominal aortic aneurysm is the most important parameter for determining whether repair is appropriate. This decision, however, must be considered in the context of long-term outcome of treatment, balancing risk for rupture with mortality from the initial procedure and all subsequent secondary procedures necessary when durability is not ideal. Information on the results of endovascular repair of small versus large aneurysms has not been available.
  
  
  METHODS
  Preoperative imaging studies and postoperative outcome were assessed in 700 patients who underwent endovascular repair of abdominal aortic aneurysm over 6 years at a single institution. Patients were divided into two groups: 416 patients (59.4%) with aneurysms smaller than 5.5 cm in diameter and 284 patients (40.6%) with aneurysms 5.5 cm or larger in diameter. Outcome variables were assessed with the Kaplan-Meier method and the log-rank test.
  
  
  RESULTS
  Patients with small and large aneurysms were comparable with regard to all baseline parameters assessed, with the single exception of a small increase in age (2.3 years) in patients with large aneurysms (P =.031). While there were no differences in rate of type II endoleaks, mid-term changes in sac diameter, or aneurysm rupture between the two groups, at 24 months patients with large aneurysms had more type I leaks (6.4% +/- 2.3% vs 1.4% +/- 0.6%; P =.011), device migration (13% +/- 4.0% vs 4.4% +/- 1.8%; P =.006), and conversion to open surgical repair (8.2% +/- 3.2% vs 1.4% +/- 1.1%; P =.031). Of greatest importance, at 24 months patient survival was diminished (71% +/- 4.6% vs 86% +/- 2.8%; P <.001) and risk for aneurysm-related death was increased (6.1% +/- 2.6% vs 1.5% +/- 1.0%; P =.011) in the group with large aneurysms.
  
  
  CONCLUSIONS
  Outcome after endovascular repair of abdominal aortic aneurysm depends on size; results appear inferior in patients with larger aneurysms. These differences attain importance when choosing between observation and repair, balancing risk for rupture against size-dependent outcome.
authors.affiliation: Department of Vascular Surgery, The Cleveland Clinic Foundation, Desk S40, 9500 Euclid Ave, Cleveland, OH 44195, USA. ourielk@ccf.org
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ouriel
authors.forename: Sunita D
authors.initials: SD
authors.lastname: Srivastava
authors.forename: Timur P
authors.initials: TP
authors.lastname: Sarac
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: O'hara
authors.forename: Sean P
authors.initials: SP
authors.lastname: Lyden
authors.forename: Roy K
authors.initials: RK
authors.lastname: Greenberg
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Clair
authors.forename: Ellis
authors.initials: E
authors.lastname: Sampram
authors.forename: Brett
authors.initials: B
authors.lastname: Butler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015607:Stents / Q000009:adverse effects*; D015996:Survival Rate; D014057:Tomography, X-Ray Computed