title: Abdominal aortic bifurcation anatomy and endograft limb size affect the use of adjunctive iliac stenting after bifurcated endograft deployment for abdominal aortic aneurysm.
abstract: BACKGROUND
  The aims of the study are: 1) to define the incidence of intraoperative endograft limb stenosis >50% (ELS) after bifurcated EVAR, 2) to find risk factors for ELS considering morphology of aortic bifurcation and structural characteristics of endograft iliac limbs, and 3) to evaluate early and follow-up outcomes of intraoperative adjunctive endograft iliac stenting.
  
  
  METHODS
  Patients treated with bifurcated EVAR for abdominal aortic aneurysm were prospectively collected from 2005 to 2011. Patient demographics, clinical risk factors, preoperative aortic bifurcation morphology (minimum and maximum diameter [ABD], calcification [ABC]), endograft iliac limb parameters (diameters [ELDs], stent material, type of endograft), ratio between ELDs and ABD), perioperative ELS and results during follow-up were analyzed. Primary outcomes were incidence of perioperative ELS and risk factors for its occurrence. Considering adjunctive stenting procedure, secondary outcomes were technical success, 30-day and mid-term iliac endograft leg patency and clinical success.
  
  
  RESULTS
  Two hundred and forty-seven patients (men 233; mean age 74±7 years) were included. Mean maximum ABD was 28.9±12.9 mm. ABC was ≥50% in 56 (22.7%) cases. Median sum of ELDs was 31 mm (IQR 13-46). Endograft limb with stainless steel and nitinol stents was deployed in 69 (27.9%) and 178 (72.1%) patients. Median ELDs/ABD ratio was 1.2 (IQR: 0.9-1.5). ELS in aortic bifurcation occurred in 42 (8.5%) endograft limbs in 36 (14.6%) patients. ABD≤20 mm, ABC≥50%, ELDs≥30 mm, nitinol endograft stents and ELDs/ABD>1.4 were identified as possible positive predictive factors. At univariate and multivariate analysis, ELDs/ABD>1.4 resulted a positive prognostic factor for ELS (0.008 and 0.022, respectively). Forty-two adjunctive stents were deployed in 36 (14.6%) patients as intraoperative adjunctive procedure. Technical success, 30-day iliac endograft leg patency was 100%. Mean follow-up was 33 months (range 6-55 months) and mid-term clinical success and iliac endograft limb patency were 100%.
  
  
  CONCLUSIONS
  ELS is a common event after EVAR with bifurcated endograft and ELDs/ABD>1.4 results positive predictive factor. Adjunctive stenting is a safe and effective procedure and ensures optimal mid-term endograft limb patency.
authors.affiliation: Division of Vascular Surgery, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Sant'Orsola-Malpighi Polyclinic Hospital, Bologna, Italy - claudiobianchinim@gmail.com.
authors.forename: Claudio
authors.initials: C
authors.lastname: Bianchini Massoni
authors.affiliation: Division of Vascular Surgery, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Sant'Orsola-Malpighi Polyclinic Hospital, Bologna, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Gargiulo
authors.affiliation: Division of Vascular Surgery, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Sant'Orsola-Malpighi Polyclinic Hospital, Bologna, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Freyrie
authors.affiliation: Division of Vascular Surgery, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Sant'Orsola-Malpighi Polyclinic Hospital, Bologna, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Gallitto
authors.affiliation: Unit of Radiology, Sant'Orsola-Malpighi Polyclinic Hospital, Bologna, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: DE Matteis
authors.affiliation: Division of Vascular Surgery, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Sant'Orsola-Malpighi Polyclinic Hospital, Bologna, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Mascoli
authors.affiliation: Division of Vascular Surgery, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Sant'Orsola-Malpighi Polyclinic Hospital, Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Stella
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D001027:Aortography; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D016208:Databases, Factual; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome; D014654:Vascular Patency