title: Observations on surveillance imaging after endovascular sealing of abdominal aortic aneurysms with the Nellix system.
abstract: OBJECTIVE
  To describe and interpret the findings of computed tomography images acquired before and after endovascular aneurysm sealing (EVAS) with the Nellix endoprosthesis and consider the potential implications of these findings on EVAS planning and performance.
  
  
  METHODS
  A retrospective review was performed of perioperative imaging from 30 consecutive patients (median age 79 years; 19 men) undergoing elective EVAS at our center between December 2013 and November 2014. The images were systematically reviewed specifically looking for endobag collapse, aortic thrombus compression, and aortic wall disruption according to definitions set a priori.
  
  
  RESULTS
  There was no perioperative mortality or endoleak after the EVAS procedure. Endobag collapse, which could potentially result in type II endoleak if occurring near a patent side branch, was seen in the endobags of 12 patients. Aortic thrombus compression, which affects the accuracy of preoperative volume measurements in predicting the amount of polymer needed to perform EVAS, was seen in 15 patients. There was one aortic wall disruption, which could potentially result in intraoperative hemorrhage, though this did not occur in this case.
  
  
  CONCLUSIONS
  These observations and their potential implications should help clinicians in planning and performing EVAS, as well as in interpreting postoperative imaging.
authors.affiliation: Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Richard G
authors.initials: RG
authors.lastname: McWilliams
authors.affiliation: Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Fisher
authors.affiliation: Department of Radiography, University of Salford, Salford, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: England
authors.affiliation: Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Francesco
authors.initials: F
authors.lastname: Torella
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001019:Aortic Rupture / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography / Q000379:methods*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D057867:Endoleak / Q000000981:diagnostic imaging / Q000209:etiology; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D004739:England; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D012189:Retrospective Studies; D015607:Stents; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000601:surgery; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: abdominal aortic aneurysm; aortic rupture; computed tomography; endobag collapse; endovascular aneurysm sealing; endovascular repair; thrombus