title: Collateral blood supply through the ophthalmic artery: a steal phenomenon analyzed by color Doppler imaging.
abstract: OBJECTIVE
  This study aimed to evaluate the retrobulbar circulatory effects of reversed ophthalmic artery flow (ROAF) on the ophthalmic artery branches by means of color Doppler imaging.
  
  
  METHODS
  The design was a case-controlled study.
  
  
  METHODS
  Among 56 consecutive patients with severe (>70% stenosis) occlusive carotid artery disease, 15 patients (26.8%) with ROAF were identified. The control group consisted of 15 patients with similar degrees of carotid artery stenosis and forward ophthalmic artery flow.
  
  
  METHODS
  Arteriography and measurement of the retrobulbar hemodynamic parameters with color Doppler imaging were performed.
  
  
  METHODS
  Blood flow velocities and resistive index in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured.
  
  
  RESULTS
  Arteriography confirmed the diagnosis of ROAF in all 15 patients. There was no patient with ROAF diagnosed by arteriography and not diagnosed by color Doppler imaging. The frequency of bilateral severe occlusive carotid artery disease was significantly higher in the ROAF group (40%) compared to the control group (6.6%) (P = 0.04). Patients with ROAF showed significantly reduced vascular resistance in the ophthalmic artery (P = 0.03), higher vascular resistance, and lower blood flow velocities in the central retinal and temporal short posterior ciliary arteries (P < 0.05).
  
  
  CONCLUSIONS
  This study suggests that patients with ROAF show a steal phenomenon, characterized by a shunt to the low-resistance intracranial circuit and reduction of retrobulbar blood flow.
authors.affiliation: Department of Ophthalmology, University of São Paulo, Brazil.
authors.forename: V P
authors.initials: VP
authors.lastname: Costa
authors.forename: S
authors.initials: S
authors.lastname: Kuzniec
authors.forename: L J
authors.initials: LJ
authors.lastname: Molnar
authors.forename: G G
authors.initials: GG
authors.lastname: Cerri
authors.forename: P
authors.initials: P
authors.lastname: Puech-Leão
authors.forename: C A
authors.initials: CA
authors.lastname: Carvalho
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000503:physiopathology*; D016022:Case-Control Studies; D019842:Ciliary Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012161:Retinal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D018615:Ultrasonography, Doppler, Color