title: Midterm results of the Zenith endograft in relation to neck length.
abstract: BACKGROUND
  Successful endovascular repair of abdominal aortic aneurysms (AAAs) requires specific infrarenal neck anatomy to allow for a durable seal and fixation. This is a single-center study reviewing outcomes in relation to neck length after placement of a Zenith endograft.
  
  
  METHODS
  Retrospective single-center review of all AAAs electively repaired with a Zenith endograft during a recent 5-year period. Patients were divided into those with infrarenal necks 4-15 mm in length and those >15 mm using center line measurements. Clinical outcomes and follow-up computed tomography scans were reviewed.
  
  
  RESULTS
  Between 2003 and 2008, 318 patients underwent elective repair of an infrarenal AAA with the Zenith endograft. Of 318 patients, 68 (21.4%) had necks measuring 4-15 mm in length and 250 (79.5%) had necks measuring >15 mm. Overall early mortality was 0.9% (p = 0.11) and the rate of type II endoleaks was 19% (p = 0.11); neither differed between the groups. Four patients in each group had immediate proximal type I endoleaks, which resolved spontaneously in two patients in each group. The remaining two in each group required further intervention (two endovascular and two conversion to open repair). Type I endoleaks and reinterventions did not differ statistically between groups (p = 0.06). On further analysis, those patients requiring reintervention or conversion for type I endoleaks had other unattractive neck features (large diameter, angulation). There have been no instances of new type I endoleaks during 5-yearfollow-up period.
  
  
  CONCLUSIONS
  These midterm results indicate that patients with shorter infrarenal necks can be treated as effectively as those with longer necks with the Zenith endograft unless these necks are tortuous or wide.
authors.affiliation: Division of Vascular Surgery, London Health Sciences Centre and the University of Western Ontario, London, Ontario, Canada. Tom.Forbes@lhsc.on.ca
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Forbes
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Harris
authors.forename: D Kirk
authors.initials: DK
authors.lastname: Lawlor
authors.forename: Guy
authors.initials: G
authors.lastname: Derose
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D057867:Endoleak / Q000209:etiology / Q000601:surgery; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D006801:Humans; D009864:Ontario; D011474:Prosthesis Design; D012086:Reoperation; D012189:Retrospective Studies; D015607:Stents; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome