title: Posttraumatic vasospasm: the epidemiology, severity, and time course of an underestimated phenomenon: a prospective study performed in 299 patients.
abstract: OBJECTIVE
  The purpose of this prospective study was to evaluate the cumulative incidence, duration, and time course of cerebral vasospasm after traumatic brain injury (TBI) in a cohort of 299 patients.
  
  
  METHODS
  Transcranial Doppler (TCD) ultrasonography studies of blood flow velocity in the middle cerebral and basilar arteries (VMCA and VBA, respectively) were performed at regular intervals during the first 2 weeks posttrauma in association with 133Xe cerebral blood flow (CBF) measurements. According to current definitions of vasospasm, five different criteria were used to classify the patients: A (VMCA > 120 cm/second); B (VMCA > 120 cm/second and a Lindegaard ratio [LR] > 3); C (spasm index [SI] in the anterior circulation > 3.4); D (VBA > 90 cm/second); and E (SI in the posterior circulation > 2.5). Criteria C and E were considered to represent hemodynamically significant vasospasm. Mixed-effects spline models were used to analyze the data of multiple measurements with an inconsistent sampling rate. Overall 45.2% of the patients demonstrated at least one criterion for vasospasm. The patients in whom vasospasm developed were significantly younger and had lower Glasgow Coma Scale scores on admission. The normalized cumulative incidences were 36.9 and 36.2% for patients with Criteria A and B, respectively. Hemodynamically significant vasospasm in the anterior circulation (Criterion C) was found in 44.6% of the patients, whereas vasospasm in the BA-Criterion D or E-was found in only 19 and 22.5% of the patients, respectively. The most common day of onset for Criteria A, B, D, and E was postinjury Day 2. The highest risk of developing hemodynamically significant vasospasm in the anterior circulation was found on Day 3. The daily prevalence of vasospasm in patients in the intensive care unit was 30% from postinjury Day 2 to Day 13. Vasospasm resolved after a duration of 5 days in 50% of the patients with Criterion A or B and after a period of 3.5 days in 50% of those patients with Criterion D or E. Hemodynamically significant vasospasm in the anterior circulation resolved after 2.5 days in 50% of the patients. The time course of that vasospasm was primarily determined by a decrease in CBF.
  
  
  CONCLUSIONS
  The incidence of vasospasm after TBI is similar to that following aneurysmal subarachnoid hemorrhage. Because vasospasm is a significant event in a high proportion of patients after severe head injury, close TCD and CBF monitoring is recommended for the treatment of such patients.
authors.affiliation: Department of Biostatistics, Brain Injury Research Center, David Geffen School of Medicine, University of California at Los Angeles, California 90095-7039, USA.
authors.forename: Matthias
authors.initials: M
authors.lastname: Oertel
authors.forename: W John
authors.initials: WJ
authors.lastname: Boscardin
authors.forename: Walter D
authors.initials: WD
authors.lastname: Obrist
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Glenn
authors.forename: David L
authors.initials: DL
authors.lastname: McArthur
authors.forename: Tooraj
authors.initials: T
authors.lastname: Gravori
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Lee
authors.forename: Neil A
authors.initials: NA
authors.lastname: Martin
mesh_terms: D000328:Adult; D020771:Anterior Cerebral Artery; D002560:Cerebrovascular Circulation; D006259:Craniocerebral Trauma / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020769:Posterior Cerebral Artery; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology; D017585:Ultrasonography, Doppler, Transcranial; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology