title: Collateral circulation in internal carotid artery occlusion. A study by duplex scan and magnetic resonance angiography.
abstract: BACKGROUND
  Clinical effects of internal carotid artery (ICA) occlusion may range from the absolute absence of symptoms to lethal hemispheric stroke. In this paper symptoms of patients with ICA occlusion have been related to the development of collateral circulation, different types of developed collateral circulation have been assessed, and the degree of sensitivity and specificity of duplex scan has been appraised.
  
  
  METHODS
  Forty-eight patients with ICA occlusion or subocclusion, 24 males and 24 females, aged between 50 and 83 years (67.7+/-7.15), underwent duplex scan and magnetic resonance (MR) angiography. Nineteen patients were completely asymptomatic, 20 patients showed permanent neurological symptoms and 9 patients had shown transient symptoms.
  
  
  RESULTS
  Twelve patients (25%) did not show any collateral circulation, 29 patients (60%) showed collateral circulation through homolateral external carotid artery branches and 7 patients (15%) showed collateral circulation through other circuits. Of the 20 patients with permanent symptoms only 8 showed collateral circulation. On the contrary, all the 19 asymptomatic patients and the 9 patients with transient symptoms showed collateral circulation. Eventually, duplex scan showed 78% sensitivity, 100%, specificity and 83% diagnostic accuracy.
  
  
  CONCLUSIONS
  Our data show: 1) a clear-cut prevalence of collateral circulation through homolateral external carotid artery branches with respect to other possible collateral circulation; 2) an inverse relationship between the development of collateral circulation and the appearance of permanent symptoms; 3) a good diagnostic accuracy of duplex scan in revealing collateral circulation in the case of ICA occlusion.
authors.affiliation: Department of Cardiovascular Medicine, Don Gnocchi Foundation, University of Florence, Florence, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Macchi
authors.forename: R
authors.initials: R
authors.lastname: Molino Lova
authors.forename: B
authors.initials: B
authors.lastname: Miniati
authors.forename: A
authors.initials: A
authors.lastname: Zito
authors.forename: C
authors.initials: C
authors.lastname: Catini
authors.forename: M
authors.initials: M
authors.lastname: Gulisano
authors.forename: C
authors.initials: C
authors.lastname: Pratesi
authors.forename: A A
authors.initials: AA
authors.lastname: Conti
authors.forename: G F
authors.initials: GF
authors.lastname: Gensini
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D011859:Radiography