title: Aneurysm neck diameter after endovascular repair of abdominal aortic aneurysms.
abstract: OBJECTIVE
  To determine aneurysm neck diameter change after endovascular repair (EVR) of abdominal aortic aneurysm (AAA) and its relationship to stent-graft diameter.
  
  
  METHODS
  The cases of 73 patients with AAAs who underwent EVR were reviewed retrospectively: 68 had preoperative imaging available. Neck diameter was reviewed by a single observer (M.F.B.) on preoperative, immediate postoperative, annual, and most recent contrast-enhanced computed tomographic scans. Baseline and follow-up neck diameters were compared with the manufacturers' values for unconstrained stent-graft diameters.
  
  
  RESULTS
  Intraobserver error was 2 mm. Aneurysm neck diameter increased from 21.8 mm (range, 17-28 mm) at baseline to 22.8 mm (range, 19-30 mm) postoperatively and 25.8 mm (range, 19-31 mm; P <.001) at a mean follow-up of 25.5 months (range, 6.2-60.8 mo). Neck diameter increase was more than 2 mm in 24 patients (33%). Mean change in the first, second, third, and fourth years was +1.63 mm, +0.52 mm, +0.25 mm, and +0.33 mm, respectively. Baseline mean stent-graft oversizing was 2.9 mm (13.7%; range, -1 to +8 mm), which decreased to 0.7 mm (range, -4 to +6 mm) at latest follow-up. Neck diameter exceeded stent-graft diameter (mean, 1.8 mm; range, 1-4 mm) in 21 cases (28%) and by more than 2 mm in five cases (6.8%). When neck diameter change was correlated with change in sac diameter, it was found to be insignificant (P =.24); however, it was significantly correlated with baseline oversizing (P =.01).
  
  
  CONCLUSIONS
  After EVR, the aneurysm neck dilates, mostly in the first 2 years, by greater than 2 mm in one third of patients. This is possibly related to the presence of the endograft. The associated reduction of stent-graft oversizing warrants continued vigilance for proximal endoleak.
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation; D015331:Cohort Studies; D004108:Dilatation, Pathologic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D015607:Stents; D013997:Time Factors