title: Long-term follow-up of patients with asymptomatic occlusion of the internal carotid artery with good and impaired cerebral vasomotor reactivity.
abstract: BACKGROUND
  Cerebral hemodynamic status might be prognostic for either the symptomatic or asymptomatic course of carotid occlusive disease. It is determined by evaluating cerebral vasomotor reactivity (VMR). We assessed VMR in asymptomatic patients with total occlusion of the internal carotid artery (ICA) and followed them to evaluate the role of impaired VMR in predicting ischaemic stroke (IS).
  
  
  METHODS
  Thirty-five patients (21 men, mean age ± SD 68 ± 7.5 years) with unilateral asymptomatic ICA occlusion were studied by transcranial Doppler and the Diamox test (intravenous 1.0 g acetazolamide) and followed for 48 months or until reaching the end-points of IS, transient ischaemic attack, or vascular death. VMR% was evaluated by recording the percent differences in peak systolic blood flow velocities in each middle cerebral artery at baseline and after Diamox administration.
  
  
  RESULTS
  Based on VMR% calculations, 14 (40%) patients had good VMRs and 21 (60%) had impaired VMRs. The global annual risk of ipsilateral ischaemic events was 5.7%. The annual ipsilateral ischaemic event risk was 1.8% in patients with good VMRs, whilst it was 7.1% in patients with impaired VMRs. An impaired VMR was significantly correlated with ipsilateral IS (Kaplan-Meier log rank statistic, P = 0.04).
  
  
  CONCLUSIONS
  Our results support the value of VMR assessment for identifying asymptomatic patients with carotid occlusion who belong to a high-risk subgroup for IS. New trials using extracranial-to-intracranial bypass surgery in patients with asymptomatic ICA occlusion and impaired VMRs are warranted.
authors.affiliation: Departments of Neurology Vascular Surgery, Assaf Harofeh Medical Center, Zerifin Stroke Unit, Department of Neurology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: I
authors.initials: I
authors.lastname: Kimiagar
authors.forename: A
authors.initials: A
authors.lastname: Bass
authors.forename: J M
authors.initials: JM
authors.lastname: Rabey
authors.forename: N M
authors.initials: NM
authors.lastname: Bornstein
authors.forename: A Y
authors.initials: AY
authors.lastname: Gur
mesh_terms: D000368:Aged; D002341:Carotid Artery Thrombosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015897:Comorbidity; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020521:Stroke / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D013995:Time; D014463:Ultrasonography