title: The cut flow index: an intraoperative predictor of the success of extracranial-intracranial bypass for occlusive cerebrovascular disease.
abstract: OBJECTIVE
  There has been a resurgence of interest in selective extracranial-intracranial bypass for revascularization of cerebrovascular occlusive disease. We evaluated the usefulness of intraoperative blood flow measurements in predicting graft success after extracranial-intracranial bypass.
  
  
  METHODS
  A retrospective review of 51 cases of extracranial-intracranial bypass for purposes of flow augmentation in the setting of cerebrovascular occlusive disease was performed. In all cases, free flow from the cut end of the donor vessel, termed cut flow, was measured. The cut flow index (CFI) (bypass flow [ml/min] / cut flow [ml/min]) was derived and correlated with bypass patency, postoperative bypass flow, cerebrovascular reserve testing, and clinical outcome.
  
  
  RESULTS
  The CFI was a significant predictor of bypass patency (P = 0.002). Using a CFI of 0.5 as a threshold, the bypass patency rate was 92% in cases with a CFI greater than 0.5 compared with 50% in cases with a CFI less than 0.5. Intraoperative bypass flow correlated well with postoperative measurements obtained from quantitative phase-contrast magnetic resonance imaging. An analysis of cases with a poor CFI indicated that a logical interpretation of bypass function can be performed during surgery.
  
  
  CONCLUSIONS
  A poor CFI can alert surgeons to potential difficulties with the donor vessel, anastomosis, or recipient vessel during surgery. Furthermore, a CFI closely approximating 1.0 provides physiological confirmation of impaired cerebrovascular reserve in the recipient bed.
authors.affiliation: Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois 60612-5970, USA. hanjani@uic.edu
authors.forename: Sepideh
authors.initials: S
authors.lastname: Amin-Hanjani
authors.forename: Xinjian
authors.initials: X
authors.lastname: Du
authors.forename: Nada
authors.initials: N
authors.lastname: Mlinarevich
authors.forename: Guido
authors.initials: G
authors.lastname: Meglio
authors.forename: Meide
authors.initials: M
authors.lastname: Zhao
authors.forename: Fady T
authors.initials: FT
authors.lastname: Charbel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002548:Cerebral Revascularization / Q000379:methods*; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011237:Predictive Value of Tests; D011859:Radiography; D012189:Retrospective Studies