title: Anatomic and flow dynamic considerations for safe right axillary artery cannulation.
abstract: OBJECTIVE
  Neuroprotection is of paramount interest in cardiac surgery. Right axillary artery cannulation is well established in aortic surgery because it significantly improves survival and outcome, but malperfusion of the right brain after direct cannulation has been reported. Anatomically, 4 vessel segments are potentially amenable for cannulation of the subclavian and axillary arteries. Clinical studies vary widely in dissection sites and cannulation techniques. We investigated critical flow dynamics in the right brain caused by arterial inflow after direct cannulation and specified cannulation positions that provide optimal cerebral perfusion.
  
  
  METHODS
  Distances from the lateral margin of the axillary artery and the subclavian artery to the origin of the vertebral artery were measured in 14 human corpses by a flexible ruler. We calculated the hemodynamics within the vertebral artery, depending on different positions of the cannula tip, in a computer-calculated model.
  
  
  RESULTS
  The mean distance from the axillary artery to the vertebral artery was 8.5 cm, and the mean distance from the subclavian artery to the vertebral artery was 6.7 cm. Computed flow calculations demonstrated reversed flow in the vertebral artery when the cannula tip was positioned too close to its orifice. To ensure safe supra-aortic flow, a cannula can be inserted securely up to 6.0 cm into the axillary artery and 4.2 cm into the subclavian artery.
  
  
  CONCLUSIONS
  Direct cannulation of the right axillary artery can lead to cerebral malperfusion, caused by an obstruction of the vertebral artery's orifice by the arterial cannula or a subclavian steal phenomenon due to flow reversal. The safety of direct axillary artery cannulation can be improved by a well-considered dissecting site and insertion length of the cannula.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe-University Hospital, Frankfurt am Main, Germany. Julia.Hillebrand@ukmuenster.de
authors.forename: Julia
authors.initials: J
authors.lastname: Hillebrand
authors.forename: Moritz Anton
authors.initials: MA
authors.lastname: Konerding
authors.forename: Mathias
authors.initials: M
authors.lastname: Koch
authors.forename: Tim
authors.initials: T
authors.lastname: Kaufmann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steinseifer
authors.forename: Anton
authors.initials: A
authors.lastname: Moritz
authors.forename: Omer
authors.initials: O
authors.lastname: Dzemali
mesh_terms: D059925:Anatomic Landmarks; D001366:Axillary Artery / Q000033:anatomy & histology* / Q000502:physiology*; D001783:Blood Flow Velocity; D002102:Cadaver; D002406:Catheterization, Peripheral / Q000009:adverse effects / Q000379:methods*; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D012039:Regional Blood Flow; D013348:Subclavian Artery / Q000033:anatomy & histology / Q000502:physiology; D014711:Vertebral Artery / Q000033:anatomy & histology / Q000502:physiology
keywords: 19; 25; AA; SA; VA; WSS; axillary artery; subclavian artery; vertebral artery; wall shear stress