title: The efficacy of direct extracranial-intracranial bypass in the treatment of symptomatic hemodynamic failure secondary to athero-occlusive disease: a systematic review.
abstract: OBJECTIVE
  The 1985 International Extracranial-Intracranial (EC-IC) Bypass Trial failed to show a benefit following surgery in patients with varying degrees of angiographic ICA stenosis. More recent studies using modern technology to identify appropriate candidates, however, have generated promising findings. As a result, controversy exists regarding the role of this technique in the treatment of symptomatic athero-occlusive disease. To this end, we performed a systematic review and quantitative analysis of the literature to determine if a subset of patients with symptomatic hemodynamic failure secondary to athero-occlusive disease may benefit from direct EC-IC bypass.
  
  
  METHODS
  We performed a MEDLINE (1985-2007) database search using the following keywords, singly and in combination: EC-IC bypass, hemodynamic failure and misery perfusion. Additional studies were identified manually by scrutinizing references from identified manuscripts, major neurosurgical journals and texts, and personal files. Our literature search divided studies into three categories: natural history of patients with stage I hemodynamic failure (16 studies, 2320 patients), natural history of patients with stage II hemodynamic failure (3 studies 163 patients), and outcomes of patients with hemodynamic failure treated by EC-IC bypass (23 studies 506 patients).
  
  
  RESULTS
  Patients with severe stage I and stage II hemodynamic failure are at higher risk of cerebral infarction than those with mild disease (p=.014, OR 1.17-4.08 and p=0.10, OR 0.89-3.63, respectively). Additionally, patients with severe hemodynamic failure respond better to surgery than those with mild disease (p=0.03, OR 0.16-0.92).
  
  
  CONCLUSIONS
  Patients with severe hemodynamic failure secondary to athero-occlusive disease appear to benefit from direct EC-IC bypass surgery. As a result, the conclusions of the 1985 International EC-IC Bypass Trial may not be applicable to this subset of patients. A randomized clinical trial involving this patient population is warranted.
authors.affiliation: Department of Neurosurgery, Columbia University, New York, NY 10032, United States.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Garrett
authors.forename: Ricardo J
authors.initials: RJ
authors.lastname: Komotar
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.forename: Maxwell B
authors.initials: MB
authors.lastname: Merkow
authors.forename: Marc L
authors.initials: ML
authors.lastname: Otten
authors.forename: Robert R
authors.initials: RR
authors.lastname: Sciacca
authors.forename: E Sander
authors.initials: ES
authors.lastname: Connolly
mesh_terms: D016893:Carotid Stenosis / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D002548:Cerebral Revascularization / Q000379:methods*; D002560:Cerebrovascular Circulation; D006439:Hemodynamics; D006801:Humans; D012720:Severity of Illness Index; D020521:Stroke / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D013699:Temporal Arteries / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome