You are assessing a 68 year old male who fell down three steps and struck his head on the ground.  His history is significant for a drug eluting stent placed after a cardiac catheterization two months ago.  As a result he is on dual antiplatelet therapy. You wonder what the impact of aspirin and clopidogrel is on the risk of intracranial hemorrhage (ICH).

While full anticoagulation is a clear risk for ICH, the additional relative risk from daily aspirin, clopidogrel, or dual antiplatelet therapy is not as clear.  A recent study was published as a pre-planned secondary analysis of a prospectively collected dataset to derive a novel tool to predict the risk of ICH following blunt trauma (1).  The result of warfarin coagulopathy having a significantly increased relative risk for ICH compared to control (no anticoagulation, no antiplatelet) is not surprising. In this study, the use of warfarin was associated with a relative risk of ICH of 1.88 (1.3-2.8) and the relative risk for neurosurgical intervention was 2.65 (1.57-4.48).  However, a surprising finding is dual antiplatelet therapy had even higher risk. The RR of ICH for aspirin and clopidogrel was 2.88 (1.5-5.4) and the need for surgical intervention was 4.75 (2.13-10.6). Aspirin and clopidogrel alone had a point relative risk higher than control but did not reach statistical significance. Patients with blunt head trauma require careful evaluation and risk stratification to assess for ICH.  This study shows that patients on dual antiplatelet therapy may be at higher risk for ICH than previously thought and the threshold for CT imaging should be lower.

This study is limited in that it did not evaluate direct oral anticoagulants (DOACs) or newer antiplatelet agents such as ticagrelor.  Further, it did not assess delayed ICH.

Reference: Probst MA, Gupta M, Hendey GW, et al. Prevalence of Intracranial Injury in Adult Patients With Blunt Head Trauma With and Without Anticoagulant or Antiplatelet Use. Annals of Emergency Medicine. January 2020. doi:10.1016/j.annemergmed.2019.10.004.