title: Results of complex aortic stent grafting of abdominal aortic aneurysms stratified according to the proximal landing zone using the Society for Vascular Surgery classification.
abstract: BACKGROUND
  Advances in endovascular technology have led to the successful treatment of complex abdominal aortic aneurysms. However, there is currently no consensus on what constitutes a juxtarenal, pararenal, or suprarenal aneurysm. There is emerging evidence that the extent of the aneurysm repair is associated with outcome. We compare the outcomes of 150 consecutive patients treated with a fenestrated or branched stent graft and present the data stratified according to the Society for Vascular Surgery classification based on proximal anatomic landing zones.
  
  
  METHODS
  A prospectively collected database of consecutive patients undergoing fenestrated or branched stent graft insertion in a tertiary center between 2008 and 2013 was retrospectively analyzed. Aneurysms were subdivided into zones according to where the area of proximal seal could be achieved in relation to the visceral arteries. Zone 8 covers the renal arteries, zone 7 covers the superior mesenteric artery, and zone 6 covers the celiac axis. Patient demographics, operative variables, mortality, and major morbidity were analyzed by univariate and multivariate analysis to assess for differences between zones.
  
  
  RESULTS
  During the study period, 150 patients were treated. There were 49 in zone 8, 76 in zone 7, and 25 in zone 6. Prior aortic surgery had been performed in 19 patients, which included 11 patients with previous endovascular aneurysm repairs. There was significantly increased blood loss (P < .001), operative time (P < .0001), total hospital stay (P = .018), and intensive care unit stay (P < .0001) as the zones ascended the aorta. There were 14 inpatient deaths recorded across all zones with a 30-day mortality rate of 8%. Logistic regression analysis for 30 day mortality showed a significant increase as the zones ascended (P = .007). Kaplan-Meier analysis showed that 5-year survival significantly deteriorated as the zones ascended (P = .039), with no significant difference in the freedom from reintervention curves between zones (P = .37).
  
  
  CONCLUSIONS
  We have shown that the extent of the aneurysm repair as determined by the proximal sealing zone is associated with outcome. Mortality, operative duration, blood loss, and hospital stay all significantly increased as the zones ascended. These data also validate the use of the proposed new classification based on aortic anatomy.
authors.affiliation: Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, United Kingdom.
authors.forename: Sanjay D
authors.initials: SD
authors.lastname: Patel
authors.affiliation: Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, United Kingdom.
authors.forename: Jason
authors.initials: J
authors.lastname: Constantinou
authors.affiliation: Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, United Kingdom.
authors.forename: Dominic
authors.initials: D
authors.lastname: Simring
authors.affiliation: Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, United Kingdom.
authors.forename: Manfred
authors.initials: M
authors.lastname: Ramirez
authors.affiliation: Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, United Kingdom.
authors.forename: Obiekezie
authors.initials: O
authors.lastname: Agu
authors.affiliation: Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, United Kingdom.
authors.forename: Hamish
authors.initials: H
authors.lastname: Hamilton
authors.affiliation: Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, United Kingdom. Electronic address: krassi.ivancev@gmail.com.
authors.forename: Krassi
authors.initials: K
authors.lastname: Ivancev
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta; D017544:Aortic Aneurysm, Abdominal / Q000145:classification / Q000150:complications / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects; D016208:Databases, Factual; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D015607:Stents; D016019:Survival Analysis