title: Incomplete circle of Willis and right axillary artery perfusion.
abstract: BACKGROUND
  The aim of our anatomic study was to assess whether the commonly used method of perfusion through the right axillary artery is sufficient in providing uniform distribution of blood to both hemispheres of the brain in patients undergoing surgery of the aortic arch. We considered that critical arteries to examine are anterior and left posterior communicating arteries of the circle of Willis because the absence or insufficiency of either one would drastically endanger perfusion to the left hemisphere of the brain. The existence and the diameters of these arteries were studied.
  
  
  METHODS
  The material was collected as a part of normal forensic medicine autopsies. The anatomy of the cerebral arteries of 87 deceased individuals was assessed by angiography and permanent silicone casts. A new classification was created for this study. According to a recent observation in the literature we defined the minimum threshold of arterial diameter that allows cross flow to be 0.5 mm. We also repeated analyses using 1 mm as a threshold, which has also been recommended.
  
  
  RESULTS
  In our material 22% of the anterior communicating arteries and 46% of the left posterior communicating arteries were missing. In this anatomic population the perfusion to the left hemisphere might have been insufficient in 14% of the patients at a threshold of 0.5 mm and in 17% at a threshold of 1 mm.
  
  
  CONCLUSIONS
  When the right axillary artery is used for perfusion, the circulation to the contralateral hemisphere seems to be good for most patients undergoing operations of the aortic arch, but additional means of brain protection are still needed.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Merkkola
authors.forename: Harri
authors.initials: H
authors.lastname: Tulla
authors.forename: Antti
authors.initials: A
authors.lastname: Ronkainen
authors.forename: Ville
authors.initials: V
authors.lastname: Soppi
authors.forename: Anni
authors.initials: A
authors.lastname: Oksala
authors.forename: Timo
authors.initials: T
authors.lastname: Koivisto
authors.forename: Mikko
authors.initials: M
authors.lastname: Hippeläinen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D001013:Aorta, Thoracic / Q000601:surgery; D001366:Axillary Artery / Q000033:anatomy & histology* / Q000502:physiology; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation; D002941:Circle of Willis / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D016319:Corrosion Casting; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010477:Perfusion