Minor head injury and direct oral anticoagulants: analysis of performance and outcomes in a large cohort in the Emergency Department

Minor head injury is defined by Italian guidelines as head trauma with Glasgow Coma Scale (GCS) of 14 or 15 at presentation and no clear signs of depressed skull fractures or fractures of the base of the skull, and no focal neurological deficits. Due to its rare but potentially catastrophic consequences, minor head trauma poses significant diagnostic challenges in the setting of Emergency Medicine. The main complication that must be ruled out following Minor Head Trauma is intracranial hemorrhage (ICH), for which the gold standard is a Computer Tomography (CT) scan of the head without contrast. Several clinical rules have been developed to detect patients at significant risk for ICH, and reliably rule out hemorrhage in the rest without need for a CT scan. Most of these systems, including the Italian guidelines, rely on clinical and anamnestic parameters, including for instance age, comorbidities, medication, mechanism of trauma, GCS, and clinical status. While some biochemical parameters have been proposed (e.g. S100B), none has entered any official guidelines yet. All these guidelines recognize coagulopathies and anticoagulant therapy as a risk factor for intracranial bleeding, and generally recommend that these patients undergo a second CT scan at 24h from trauma to rule out delayed bleeding. These guidelines do not differentiate between traditional vitamin K antagonists (VKA, e.g. warfarin) and New Oral Anticoagulants (NOAC). A few studies have analyzed the performances of VKAs and NOACs in the setting of minor head trauma, but the results have so far been inconclusive due to small study sizes and heterogeneous definition of minor head trauma. In this retrospective cohort study, we analyzed admissions for head trauma in 2016 and 2017 at the Emergency Department of Hospital S. Matteo in Pavia, to assess whether patients in therapy with NOACs have a different risk profile compared with patients treated with VKAs, antiplatelet drugs, or no relevant therapy. We filtered the hospital’s database for patients diagnosed with Head Trauma, Head/Neck/Face Trauma, or Intracranial Hemorrhage. We excluded patients with GCS<14, patients without any traumatic history (i.e. spontaneous hemorrhage), as well as those with injuries and mechanisms only involving the face, and those being re-admitted for an already registered trauma. Some additional patients had to be excluded due to insufficient data. Each patient was classified according to therapy, presence of bleeding, and various other clinical and anamnestic parameters, also taken with the purpose of running internal performance analyses. The main purpose of our work is to provide evidential guidance for a subsequent prospective study comparing VKAs and NOACs following a standardized observational protocol. The primary outcome is the need of neurosurgical intervention or death, with a secondary outcome being the presence of any bleeding on CT head. The primary outcome was measured in collaboration with the ward of Neurosurgery, and also by checking readmissions to our unit within the first 30 days from presentation. The entity of the bleedings on CT was re-assessed and measured by specialists in Radiology. The preliminary results of this study suggest that NOACs have a better safety profile than VKAs in the setting of minor head trauma. The nature of this retrospective study prevents us from drawing any definitive conclusions, but this work highlights the value of further investigating the performance of NOACs in minor head trauma with a prospective observational study.