title: Frequency and clinical impact of asymptomatic cerebral infarction due to vasospasm after subarachnoid hemorrhage.
abstract: OBJECTIVE
  The authors sought to determine frequency, risk factors, and impact on outcome of asymptomatic cerebral infarction due to vasospasm after subarachnoid hemorrhage (SAH).
  
  
  METHODS
  The authors prospectively studied 580 patients with SAH admitted to their center between July 1996 and May 2002. Delayed cerebral ischemia (DCI) from vasospasm was defined as 1) a new focal neurological deficit or decrease in level of consciousness, 2) a new infarct revealed by follow-up CT imaging, or both, after excluding causes other than vasospasm. Outcome at 3 months was assessed using the modified Rankin Scale.
  
  
  RESULTS
  Delayed cerebral ischemia occurred in 121 (21%) of 580 patients. Of those with DCI, 36% (44 patients) experienced neurological deterioration without a corresponding infarct, 42% (51 patients) developed an infarct in conjunction with neurological deterioration, and 21% (26 patients) had a new infarct on CT without concurrent neurological deterioration. In a multivariate analysis, risk factors for asymptomatic DCI included coma on admission, placement of an external ventricular drain, and smaller volumes of SAH (all p < or = 0.03). Patients with asymptomatic DCI were less likely to be treated with vasopressor agents than those with symptomatic DCI (64 vs 86%, p = 0.01). After adjusting for clinical grade, age, and aneurysm size, the authors found that there was a higher frequency of death or moderate-to-severe disability at 3 months (modified Rankin Scale Score 4-6) in patients with asymptomatic DCI than in patients with symptomatic DCI (73 vs 40%, adjusted odds ratio 3.9, 95% confidence interval 1.3-12.0, p = 0.017).
  
  
  CONCLUSIONS
  Approximately 20% of episodes of DCI after SAH are characterized by cerebral infarction in the absence of clinical symptoms. Asymptomatic DCI is particularly common in comatose patients and is associated with poor outcome. Strategies directed at diagnosing and preventing asymptomatic infarction from vasospasm in patients with poor-grade SAH are needed.
authors.affiliation: Neurological Intensive Care Unit, Division of Neurocritical Care, Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Schmidt
authors.forename: Katja E
authors.initials: KE
authors.lastname: Wartenberg
authors.forename: Andres
authors.initials: A
authors.lastname: Fernandez
authors.forename: Jan
authors.initials: J
authors.lastname: Claassen
authors.forename: Fred
authors.initials: F
authors.lastname: Rincon
authors.forename: Noeleen D
authors.initials: ND
authors.lastname: Ostapkovich
authors.forename: Neeraj
authors.initials: N
authors.lastname: Badjatia
authors.forename: Augusto
authors.initials: A
authors.lastname: Parra
authors.forename: E Sander
authors.initials: ES
authors.lastname: Connolly
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Mayer
mesh_terms: D000328:Adult; D000368:Aged; D002531:Cerebellum / Q000098:blood supply / Q000000981:diagnostic imaging; D002544:Cerebral Infarction / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D015331:Cohort Studies; D003128:Coma / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial; D020301:Vasospasm, Intracranial / Q000150:complications* / Q000175:diagnosis / Q000209:etiology*