title: Recurrence in intracranial atherosclerotic disease: a stenosis-based analysis.
abstract: BACKGROUND
  Intracranial atherosclerotic disease is a common cause of stroke; its incidence and prevalence vary widely by ethnicity. The aim of our study was to analyze the recurrence rate of cerebrovascular events in patients with symptomatic and asymptomatic intracranial stenosis (IS).
  
  
  METHODS
  We conducted a historical cohort study including all patients admitted in our hospital for stroke or transient ischemic attack (TIA) during 2011 and 2012 with information on intracranial circulation (ultrasonography and/or computed tomography angiography). We identified patients with symptomatic and asymptomatic IS and studied the recurrence of cerebrovascular events (TIA or ischemic stroke within the territory of the stenosis) for a minimum follow-up period of 6 months after the diagnosis of IS. For the recurrence rate estimation, patients with other potentially embolic diseases (in cervical arteries or heart) were excluded. We calculated the rate of recurrence of cerebrovascular events and performed Kaplan-Meier survival curves for symptomatic and asymptomatic IS.
  
  
  RESULTS
  We investigated 1302 patients, mean age was 72.41 years (standard deviation 12.75). We identified 218 IS in 158 patients, 77 were symptomatic and 141 were asymptomatic. The recurrence rate of cerebrovascular events was 12.32 per 100 patient-years, with a mean time to recurrence of 1.73 months for symptomatic intracranial stenosis (SIS) and .88 per 100 patient-years for asymptomatic IS (P < .001).
  
  
  CONCLUSIONS
  These results indicate a high risk of early recurrence of stroke in the territory of a SIS, highlighting the importance of its early diagnosis and aggressive treatment.
authors.affiliation: Neurology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal. Electronic address: anargouveia86@gmail.com.
authors.forename: Ana
authors.initials: A
authors.lastname: Gouveia
authors.affiliation: Stroke Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Sargento-Freitas
authors.affiliation: Faculty of Medicine of the University of Coimbra, Coimbra, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Penetra
authors.affiliation: Stroke Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Silva
authors.affiliation: Stroke Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Machado
authors.affiliation: Stroke Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Cordeiro
authors.affiliation: Stroke Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Cunha
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D016893:Carotid Stenosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000150:complications / Q000000981:diagnostic imaging; D002546:Ischemic Attack, Transient / Q000453:epidemiology* / Q000503:physiopathology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000503:physiopathology; D014463:Ultrasonography
keywords: Intracranial atherosclerotic disease; intracranial stenosis; recurrence rate; time to recurrence