title: Thromboelastography defines late hypercoagulability after TBI: a pilot study.
abstract: BACKGROUND
  Traumatic brain injury (TBI) is associated with a hypercoagulable state, the mechanism and duration of which remain unclear. We sought to determine whether thromboelastography (TEG) analysis could identify the hypercoagulable state after TBI, as defined by elevations in maximal amplitude (MA), thrombus generation (TG), G value (G), and alpha angle (αA).
  
  
  METHODS
  Patients with moderate-severe TBI, defined primarily as a GCS <12, admitted between 1/2012 and 8/2013 were eligible for enrolment in this prospective cohort study. TEG profiles were obtained between 0-24 h (T1), 24-48 h (T2), 48-72 h (T3), 72-96 h (T4), and 96-120 h (T5) after admission. Early TEG was defined as 0-48 h, and late TEG was defined as >48 h.
  
  
  RESULTS
  Twenty five patients (80 % men) and 7 age- and sex-matched control subjects were studied. Median age was 38 years (range 18-85). Early MA was [63.6 mm (60.5, 67.4)] versus late MA [69.9 mm (65.2,73.9); p = 0.02], early TG was [763.3 mm/min (712.8, 816.2)] versus late TG [835.9 mm/min (791.2,888.3); p = 0.02], and early G was [8.8 d/cm(2) (7.7,10.4)] versus late G [11.6 d/cm(2) (9.4,14.1); p = 0.02]. Study patients had higher MA (p = 0.02), TG (p = 0.03), and G (p = 0.02) values at T5 compared to controls. There was a linear increase per day of MA by 2.6 mm (p = 0.001), TG 31.9 mm/min (p ≤ 0.001), and G value by 1.3 d/cm(2) (p ≤ 0.001) when clustered by pairs in regression analysis. Lower MA values trended toward home discharge (p = 0.08).
  
  
  CONCLUSIONS
  The data suggest a progressive and delayed hypercoagulable state observed days after initial TBI. The hypercoagulable state may reflect excess platelet activity.
authors.affiliation: Department of Neurology, Perelman School of Medicine and the Hospital of the University of Pennsylvania, 3 West Gates Building, 3400 Spruce Street, Philadelphia, PA, 19104, USA, allie.massaro@gmail.com.
authors.forename: Allie M
authors.initials: AM
authors.lastname: Massaro
authors.forename: Sean
authors.initials: S
authors.lastname: Doerfler
authors.forename: Kelsey
authors.initials: K
authors.lastname: Nawalinski
authors.forename: Bernard
authors.initials: B
authors.lastname: Michel
authors.forename: Nicolette
authors.initials: N
authors.lastname: Driscoll
authors.forename: Connie
authors.initials: C
authors.lastname: Ju
authors.forename: Hiren
authors.initials: H
authors.lastname: Patel
authors.forename: Francis
authors.initials: F
authors.lastname: Quattrone
authors.forename: Suzanne
authors.initials: S
authors.lastname: Frangos
authors.forename: Eileen
authors.initials: E
authors.lastname: Maloney-Wilensky
authors.forename: Michael
authors.initials: M
authors.lastname: Sean Grady
authors.forename: Sherman C
authors.initials: SC
authors.lastname: Stein
authors.forename: Scott E
authors.initials: SE
authors.lastname: Kasner
authors.forename: Monisha A
authors.initials: MA
authors.lastname: Kumar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001930:Brain Injuries / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D013916:Thrombelastography / Q000379:methods*; D019851:Thrombophilia / Q000175:diagnosis* / Q000209:etiology; D055815:Young Adult