title: Long-term follow-up of asymptomatic patients with major artery occlusion: rate of symptomatic change and evaluation of cerebral hemodynamics.
abstract: OBJECTIVE
  The natural history of asymptomatic major cerebral artery occlusive disease is unclear. Rate of symptomatic change, appearance of new lesions on MR images, and cerebral hemodynamics were analyzed for patients with asymptomatic major cerebral artery occlusion.
  
  
  METHODS
  This prospective study included asymptomatic patients who had occlusive disease between 1992 and 1995. MR imaging and MR angiography were used to detect internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion in 3965 neurologically asymptomatic patients and for follow-up of affected patients for 67 to 105 months (mean, 79 months). Regional cerebral blood flow and cerebrovascular reserve capacity were examined by xenon-enhanced CT at rest and after the administration of acetazolamide, respectively.
  
  
  RESULTS
  Eighteen patients had MCA occlusion and 17 had ICA occlusion. During the follow-up period, five patients became symptomatic (four with MCA occlusion and one with ICA occlusion), with no significant difference (P = .332) in the rate of symptomatic change. Among these five patients, new infarction occurred on the ipsilateral side in three patients, contralateral side in one, and bilateral sides in one. New stenotic or occlusive changes occurred in three patients. The patients were divided into groups: group A, without new lesions on MR images (n = 23), and group B, with new lesions (n = 12). There was no significant difference in regional cerebral blood flow value between groups A and B in the whole hemisphere, anterior cerebral artery territory, or MCA territory. There was a significant difference in cerebrovascular reserve capacity between groups A and B between the affected side (P = .00051 and P = .00068, respectively) and the contralateral side (P = .00101 and P = .00115, respectively) for the whole hemisphere and MCA territory, and the difference was more severe on the affected side in both regions.
  
  
  CONCLUSIONS
  These pilot data suggest that asymptomatic MCA occlusion has a worse prognosis than does ICA occlusion. Silent events are common bilaterally. This may be because of hemodynamic factors or perhaps MCA occlusion is a marker for a more progressive type of atherosclerosis. A prospective study involving assessment of hemodynamics and baseline stroke risk factors in patients with MCA occlusion is indicated.
authors.affiliation: Department of Neurosurgery, Yamanashi Medical University, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Miyazawa
authors.forename: K
authors.initials: K
authors.lastname: Hashizume
authors.forename: M
authors.initials: M
authors.lastname: Uchida
authors.forename: H
authors.initials: H
authors.lastname: Nukui
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000175:diagnosis / Q000503:physiopathology*; D002536:Cerebral Arteries; D002560:Cerebrovascular Circulation; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014978:Xenon
chemical_list: D014978:Xenon