title: Validation of pre-procedural aortic aneurysm volume calculations to estimate procedural fill volume of endobags in endovascular aortic sealing.
abstract: BACKGROUND
  Endovascular aortic sealing (EVAS) with a sac anchoring endoprosthesis excludes abdominal aortic aneurysms based on polymer filling of endobags. Primary objective was to assess the reliability of pre-procedural computed tomography (CT) scans based calculations of required endobag volume in relation to intraoperative volume of the endobags.
  
  
  METHODS
  Forty elective EVAS patients were included. Pre-procedural estimations of endobag volume were based on CT segmentations of aortic flow lumen volume, including both automated and manually-adjusted segmentations, performed by two experienced users. Additionally, changes in maximum AAA diameter, thrombus volume and total AAA volume were calculated from pre- and post-procedural CT scans.
  
  
  RESULTS
  Automatically determined volumes were comparable to manually-adjusted calculations (75.3 vs. 75.7 mL) and inter-observer agreement regarding pre-EVAS calculations of prefill volume appeared almost perfect with an intra-class correlation coefficient of 0.98 (95% CI: 0.96-0.99). The mean pressure of the endobags was 185 mmHg. Manually-adjusted pre-procedural volume calculations underestimated procedural volume of the endobags (-11.3±9.9 mL). Differences between pre-EVAS and procedural volume measurements were independent from endobag pressure (r=-0.06, P=0.72), prepocedural thrombus volume (r=-0.303, P=0.057) and changes in total AAA volume (r=0.02, P=0.91). A significant association was determined between differences in pre-EVAS and endobag volume versus changes in thrombus volume pre- and post-procedural (r=0.39, P=0.01).
  
  
  CONCLUSIONS
  In this validation study, pre-procedural volume measurements underestimate the actual fill volume of the endobags. It should be advised to perform a prefill of the endobags during the EVAS procedure.
authors.affiliation: Department of Vascular Surgery, St. Antonius Hospital, Nieuwegein, The Netherlands - j.boersen@antoniusziekenhuis.nl.|MIRA Institute for Technical Medicine and Biomedical Technology, University of Twente, Enschede, The Netherlands - j.boersen@antoniusziekenhuis.nl.
authors.forename: Johannes T
authors.initials: JT
authors.lastname: Boersen
authors.affiliation: Department of Surgery, Rijnstate Hospital, Arnhem, The Netherlands.
authors.forename: Leo H
authors.initials: LH
authors.lastname: van den Ham
authors.affiliation: Department of Vascular Surgery, St. Elisabeth Hospital, Tilburg, The Netherlands.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Heyligers
authors.affiliation: Department of Vascular Surgery, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
authors.forename: Anco C
authors.initials: AC
authors.lastname: Vahl
authors.affiliation: Department of Vascular Surgery, St. Elisabeth Hospital, Tilburg, The Netherlands.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Vriens
authors.affiliation: Department of Surgery, Rijnstate Hospital, Arnhem, The Netherlands.
authors.forename: Michel M
authors.initials: MM
authors.lastname: Reijnen
authors.affiliation: Department of Vascular Surgery, St. Antonius Hospital, Nieuwegein, The Netherlands.
authors.forename: Jean-Paul P
authors.initials: JP
authors.lastname: de Vries
mesh_terms: D000800:Angioplasty, Balloon / Q000295:instrumentation*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000601:surgery*; D001027:Aortography / Q000379:methods*; D001331:Automation; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D000072226:Computed Tomography Angiography; D005260:Female; D006801:Humans; D008297:Male; D061330:Multidetector Computed Tomography; D009426:Netherlands; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011474:Prosthesis Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D015607:Stents; D016896:Treatment Outcome