title: Review of postoperative CT and ultrasound for endovascular aneurysm repair using Talent stent graft: can we simplify the surveillance protocol and reduce the number of CT scans?
abstract: BACKGROUND
  Simplifying a postoperative surveillance protocol for endovascular aneurysm repair (EVAR) requires quality control comparing computerized tomography (CT) and ultrasound (US) results of abdominal aortic aneurysm (AAA) diameter measurements and endoleaks.
  
  
  OBJECTIVE
  To test if US is comparable to CT, then assess a simplified follow-up with our conventional surveillance to assess patient safety.
  
  
  METHODS
  During 2001-2006, data on 56 patients treated with Talent stent graft were prospectively registered. Median follow-up was 41.5 months (range, 2-94 months), with CT, US, and plain film abdomen X-rays (PFA) at 1, 6, and 12 months, then yearly. Bland-Altman plot was used to assess the agreement between CT and US measuring the AAA diameters and mixed model by the time effect to assess the difference in diameter over time. Sensitivity and specificity for detection of endoleaks by US, with CT as 'gold standard' were calculated. A simplified surveillance protocol with US/PFA at 6 and 8 weeks, CT/US/PFA at 1 year, and yearly US/PFA thereafter, was evaluated. CT was carried out when poor visibility, endoleak detected, AAA diameter increase (≥5 mm) on US or migration (≥10 mm) on PFA. This regime was compared with our conventional follow-up protocol.
  
  
  RESULTS
  Diameter measurements on US appear comparable to CT with 91% specificity and 85% sensitivity for endoleaks detected by US. Using the simplified surveillance protocol no endoleaks, migrations, or endotension requiring treatment were overlooked. The simplified protocol generated 53 selective CT scans, avoiding approximately 144 CT scans. If further simplified by omitting the 1-year CT scan, one type II endoleak would be missed with a 1-year delay, eliminating a further 45 CT scans.
  
  
  CONCLUSIONS
  US appears comparable to CT in the follow-up of Talent stent grafts in our institution. The proposed simplified surveillance protocol seems safe and can lead to a significant reduction in the number of CT scans.
authors: Oslo Vascular Centre, HLK Department, Oslo University Hospital Aker, Oslo, Norway. thomasnyheim1@yahoo.com
authors: Thomas
authors: T
authors: Nyheim
authors: Lars Erik
authors: LE
authors: Staxrud
authors: L
authors: L
authors: Rosen
authors: Carl Erik
authors: CE
authors: Slagsvold
authors: Gunnar
authors: G
authors: Sandbaek
authors: Jørgen J
authors: JJ
authors: Jørgensen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D057867:Endoleak / Q000000981:diagnostic imaging*; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler / Q000379:methods*