title: Immediate Change in Suprarenal Neck Angulation After Endovascular Aneurysm Repair: Comparison of the Ovation Stent-Graft Inflatable Sealing Rings to a Conventional Self-Expanding Stent-Graft.
abstract: OBJECTIVE
  To compare the immediate suprarenal neck angulation change between the Ovation stent-graft, with its inflatable sealing rings, and a stent-graft with a conventional sealing mechanism.
  
  
  METHODS
  A case-control study was conducted in which 30 consecutive patients (mean age 67 years; all men) with abdominal aortic aneurysm (AAA) treated with the Ovation stent-graft (group O) were retrospectively compared with 24 patients (mean age 77 years; all men) contemporaneously treated with the Endurant stent-graft (group E) at 3 high-volume tertiary vascular centers. The variables recorded were the aortic neck length, preoperative and postoperative angulation, minimum and maximum diameters of the infrarenal neck, as well as the maximum AAA diameter. All patients had undergone preoperative and postoperative (within 30 days) computed tomographic angiography. Multiple regression analysis compared the relative contribution to neck angulation change of each geometric parameter and the type of endograft. Data are presented as the mean ± standard deviation.
  
  
  RESULTS
  The mean preoperative suprarenal neck angulation in group O was 23.2°±18.0° compared with 23.8°±22.9° in group E (t test, p=0.91). The neck lengths were 29.2±14.6 and 23.2±11.0 mm in groups O and E, respectively (p=0.1). Similarly, the minimum and maximum neck diameters were 22.4±2.6 and 25±3.5 mm, respectively, in group O vs 23.3±3.6 mm and 27.0±5.7 mm, respectively, in group E (p=0.3 and 0.12, respectively). The maximum transverse diameters of the AAA in the 2 groups were comparable, that is, 57.0±9.0 mm in group O vs 53.2±11.1 mm in group E (p=0.17). The Ovation stent-graft caused greater decrease in the aortic neck angulation postoperatively compared with the Endurant device (13.2°±16.1° vs 6.1°±5.9°, p=0.04). Multiple regression analysis revealed that preoperative neck angulation (β coefficient 0.37, p<0.001) and the type of endograft (β coefficient -7.91, p=0.01) had significant influence on the postoperative neck angulation change. The intraclass correlation coefficient ranged from 0.951 to 0.990 for the preoperative measurements and from 0.911 to 0.999 for the postoperative measurements for each examiner or the total of estimates at the measurement time points.
  
  
  CONCLUSIONS
  The Ovation stent-graft induces greater postoperative reduction in the AAA neck angulation compared to an endograft with stent-supported graft seal. Expanded research to infrarenal angle as well to greater angles and correlation to clinical events is justified.
authors.affiliation: Department of Vascular Surgery, "Democritus" University of Thrace, University Hospital of Alexandroupolis, Greece efstratiosgeorg@gmail.com.
authors.forename: Efstratios
authors.initials: E
authors.lastname: Georgakarakos
authors.affiliation: Department of Vascular Surgery, University Hospital of Heraklion, University of Crete Medical School, Heraklion, Greece.
authors.forename: Christos V
authors.initials: CV
authors.lastname: Ioannou
authors.affiliation: First Surgical Clinic, General Hospital "G. Papanikolaou" Exohi, Thessaloniki, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Trellopoulos
authors.affiliation: Department of Vascular Surgery, University Hospital of Heraklion, University of Crete Medical School, Heraklion, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Kontopodis
authors.affiliation: Laboratory of Radiology, "Euromedic" Medical Center, Thessaloniki, Greece.
authors.forename: Athanasia
authors.initials: A
authors.lastname: Papachristodoulou
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital, and University Clinic of Münster, Germany.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Torsello
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital, and University Clinic of Münster, Germany.
authors.forename: Theodosios
authors.initials: T
authors.lastname: Bisdas
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D057510:Endovascular Procedures / Q000379:methods*; D006801:Humans; D008297:Male; D012077:Renal Artery / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D015607:Stents; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Endurant stent-graft; Ovation stent-graft; abdominal aortic aneurysm; aortic neck; endograft; endovascular aneurysm repair; neck dilatation; nitinol stent; radial force; sealing rings; stent-graft; suprarenal angulation; suprarenal stent