title: Long-term natural history of intracranial arterial stenosis: an MRA follow-up study.
abstract: BACKGROUND
  Intracranial arterial stenosis (ICAS) is a major cause of ischemic stroke in Asians. Despite the clinical importance of ICAS, the literature on the natural history of ICAS has been less enlightening. The aims of our study were to evaluate a long-term natural course of symptomatic and asymptomatic ICAS.
  
  
  METHODS
  102 subjects (37 symptomatic and 65 asymptomatic) underwent follow-up MR angiography (MRA) with a median time interval between initial and follow-up MRA of 5.7 years (range 3.6-8.5 years). For each patient, the extent of stenosis of five arteries (both middle cerebral arteries, both intracranial internal carotid arteries, and basilar artery) was classified according to five grades, by consensus: normal, mild (signal reduction <50%), moderate (signal reduction ≥50%), severe (focal signal loss with the presence of a distal signal), and occlusion. Because the sample size was too small to adjust for multiple confounders, we applied the propensity score.
  
  
  RESULTS
  Mean (Standard deviation) age at initial MRA was 63.5 (9.6) and 54% were men. The progression rate of ICAS differed significantly between symptomatic and asymptomatic patients (22 vs. 8%, p < 0.01), indicating a 3-fold risk of progression for symptomatic stenosis compared with asymptomatic stenosis [odds ratio (OR) 3.27, 95% confidence interval (CI) 1.08-9.95]. After adjustment for propensity score, the OR was 4.84 (95% CI, 1.40-16.7). In the matched cohort, the relative risk of stenosis progression was 5.20 for symptomatic stenosis (95% CI 1.00-27.23) compared with asymptomatic stenosis.
  
  
  CONCLUSIONS
  We found a greater risk of progression for symptomatic stenosis compared with asymptomatic stenosis.
authors.affiliation: Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Wi-Sun
authors.initials: WS
authors.lastname: Ryu
authors.forename: Sang-Soon
authors.initials: SS
authors.lastname: Park
authors.forename: Young-Seo
authors.initials: YS
authors.lastname: Kim
authors.forename: Su-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Kyusik
authors.initials: K
authors.lastname: Kang
authors.forename: Chulho
authors.initials: C
authors.lastname: Kim
authors.forename: Chul-Ho
authors.initials: CH
authors.lastname: Sohn
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Byung-Woo
authors.initials: BW
authors.lastname: Yoon
mesh_terms: D000368:Aged; D058070:Asymptomatic Diseases; D002539:Cerebral Arterial Diseases / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D002536:Cerebral Arteries / Q000473:pathology*; D003251:Constriction, Pathologic; D018450:Disease Progression; D005260:Female; D006801:Humans; D016015:Logistic Models; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D057216:Propensity Score; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors