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CREST study: Patients presenting to the emergency room with blunt head trauma and preinjury warfarin or clopidogrel use have a high incidence of immediate intracranial hemorrhage, but a very low incidence delayed intracranial hemorrhage. Thus, if the initial head CT is negative, you should be able to discharge the patient home…

Why It’s Important for Emergency Medicine

Every physician can intuit that patients being treated with anticoagulation or antiplatelet medications are at an increased risk of bleed in the setting of blunt head trauma. This prospective study gives us a good idea of the incidence of immediate ICH in an anticoagulated population. More importantly, it established that the risk of delayed ICH (traumatic ICH diagnosed within 2 weeks of injury after a normal CT) was extremely low, about 1 delayed bleed out of 200. This should allow for the safe discharge of those who are otherwise well with a negative head CT – a group whom was previously routinely admitted, or even had their anticoagulation reversed. It is emphasized that these patients should be given good instructions, and probably have someone with them to watch them.

Major Points

Warfarin group

  • 37/724 (5.1%) had immediate ICH
  • 4/687 (0.6%) suffered delayed ICH

Plavix group

  • 33/276 (12.0%) had immediate ICH
  • 0/243 suffered delayed ICH

Design & Results

  • Prospective observational study; 2 trauma centers and 4 community hospitals.
  • Inclusion: Any degree of blunt head trauma + preinjury warfarin or plavix use within the last 7 days.
  • Patients using both plavix + warfarin were excluded. Follow-ups were obtained from either hospital records or phone calls.
  • 1101 enrolled, 1064 included. 4 lost to followup. 87.6% were GCS 15, 34.2% were admitted.
  • 7.0% had immediate ICH, 0.4% had delayed ICH.


  • There was significantly more aspirin use in the plavix group. This could possibly account for the increased incidence of immediate ICH. There is no data for those just on ASA.
  • Repeat CT’s were obtained at the physician’s discretion.
  • Was there a population of missed ‘asymptomatic’ delayed ICH? If so, does it matter?
  • Patients on warfarin may be more aware of their bleeding risk, leading to a lower threshold to present after blunt trauma, accounting for the difference in ICH between plavix and warfarin. In fairness, the clinical attributes between the warfarin and plavix groups are very similar.

Reviewed by A. WilliamsMIA 2012 = Most Interesting Articles series of 2012

Nishijima D, Offerman S, Ballard D, et al. Immediate and delayed traumatic intracranial hemorrhage in patients with head trauma and preinjury warfarin or clopidogrel use. Ann Emerg Med. 2012;59(6):460-8.e1-7. [PubMed]
Michelle Lin, MD
ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco
Michelle Lin, MD


Professor of Emerg Med at UCSF-Zuckerberg SF General. ALiEM Founder @aliemteam #PostitPearls at https://t.co/50EapJORCa Bio: https://t.co/7v7cgJqNEn
Michelle Lin, MD