title: Clinical significance of posterior circulation changes after revascularization in patients with moyamoya disease.
abstract: OBJECTIVE
  It has been noted that the posterior circulation serves as an important source of collateral blood supply in moyamoya disease. Since most of the literature has focused on non-operative cases and many symptomatic patients receive surgical revascularization, we evaluated the posterior circulation changes after revascularization and found that progressive posterior cerebral artery (PCA) steno-occlusive changes after revascularization caused cerebral hemodynamic compromise and clinical deterioration in a significant portion of patients.
  
  
  METHODS
  Twenty-three moyamoya disease patients with ischemic presentation who received revascularization with complete angiography and xenon CT during a minimum of 3 years' clinical follow-up were enrolled. Revascularization was performed in 38 hemispheres. Pre- and postoperative angiography were reviewed to determine the internal carotid artery (ICA) stage, PCA stage, leptomeningeal collateral (LMC) grade, and Matsushima synangiosis grade. The postoperative regional cerebral blood flow (CBF) and cerebral vascular reserve (CVR) were recorded and correlated with angiographic findings and clinical outcome.
  
  
  RESULTS
  Progression of ICA staging was noted in 23 sides (55.2%), and progression of PCA staging was noted in 18 sides (47.4%). Among the 18 cases of PCA stage progression, an associated decrease in LMC grade was noted in 12 sides (66.7%). These changes were associated with decreased regional CBF and CVR, which also explained the recurrent ischemic symptoms in 27.8% of these patients. In contrast, LMC grade increased in 15 (65.2%) sides of patients with ICA progression.
  
  
  CONCLUSIONS
  Progressive steno-occlusive change in the PCA after revascularization is associated with a reduction in LMC blood flow and cerebral ischemia in moyamoya patients. This phenomenon might cause recurrent ischemic symptoms in 27.8% of patients.
authors: Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
authors: Abel Po-Hao
authors: AP
authors: Huang
authors: Hon-Man
authors: HM
authors: Liu
authors: Dar-Ming
authors: DM
authors: Lai
authors: Chi-Cheng
authors: CC
authors: Yang
authors: Yi-Hsin
authors: YH
authors: Tsai
authors: Kuo-Chuan
authors: KC
authors: Wang
authors: Shih-Hung
authors: SH
authors: Yang
authors: Meng-Fai
authors: MF
authors: Kuo
authors: Yong-Kwang
authors: YK
authors: Tu
mesh_terms: D000328:Adult; D001808:Blood Vessels / Q000503:physiopathology; D002533:Cerebral Angiography; D002548:Cerebral Revascularization; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003097:Collateral Circulation / Q000502:physiology; D018450:Disease Progression; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D018810:Magnetic Resonance Angiography; D009072:Moyamoya Disease / Q000503:physiopathology* / Q000523:psychology / Q000601:surgery*; D010291:Paresis / Q000209:etiology; D020769:Posterior Cerebral Artery / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult