title: How to calculate the main aortic graft-diameter for a chimney-graft.
abstract: BACKGROUND
  The aim of this paper was to present a mathematical model to calculate the required main aortic graft-diameter for parallel chimney-grafts.
  
  
  METHODS
  Geometric approximation model, developed to allow for a standardized calculation of the main aortic graft-diameter determined by the aortic diameter and the diameter of the chimney-graft.
  
  
  RESULTS
  We propose a mathematical formula using circular segments of the aorta and the chimney-graft and provide a table with recommended main aortic graft-diameters for single chimney-grafts of 6 and 8 mm.
  
  
  CONCLUSIONS
  Geometric approximation can be used to calculate the required main aortic graft-diameter. For parallel running chimney-grafts a significant degree of oversizing is necessary to allow the main aortic body to surround the chimney and to prevent the occurrence of gutters, which may cause type-1 endoleaks.
authors.affiliation: Department of Vascular Medicine, University Heart Center, University Hospital Eppendorf, Hamburg, Germany - tilokoelbel@gmail.com.
authors.forename: Tilo
authors.initials: T
authors.lastname: Kölbel
authors.forename: Sebastian W
authors.initials: SW
authors.lastname: Carpenter
authors.forename: Anusch
authors.initials: A
authors.lastname: Taraz
authors.forename: Martin
authors.initials: M
authors.lastname: Taraz
authors.forename: Axel
authors.initials: A
authors.lastname: Larena-Avellaneda
authors.forename: Eike S
authors.initials: ES
authors.lastname: Debus
mesh_terms: D015901:Angiography, Digital Subtraction; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D057867:Endoleak / Q000517:prevention & control; D006801:Humans; D008433:Mathematics; D008953:Models, Anatomic; D012307:Risk Factors; D015607:Stents; D016896:Treatment Outcome; D014654:Vascular Patency