Kerstin de Wit: Head Injury in Anticoagulated Patients


The rate of anticoagulant use has been steadily increasing in Canada. In particular, direct oral anticoagulant (DOAC) prescriptions have increased among the elderly, mostly as a means of stroke prophylaxis in atrial fibrillation patients.

Head injured patients often undergo head computed tomography (CT) scanning. During derivation, ED decision rules for determining who requires head CT after head injury excluded anticoagulated patients, and these guidelines now recommend CT head scans for all anticoagulated patients with a head injury.

Preparatory work

We conducted a systematic review to determine the incidence of intracranial hemorrhage in anticoagulated head injured patients with a GCS of 15. A total of five studies (including 4,080 anticoagulated patients with a GCS score of 15) from the Netherlands, Italy, France, USA and UK were included in the analysis. The majority of patients were on vitamin K antagonists (98.3%) followed by direct oral anticoagulants (1.5%). There was significant heterogeneity between studies. The random effects pooled incidence of ICH was 8.9% (95% CI 5.0-13.8%).


To assess the safety of applying the Canadian CT head rule to anticoagulated emergency department patients who present with head injury.


This is a prospective, multicenter study recruiting consecutive anticoagulated patients presenting to the emergency department after a minor head injury.

It is expected that there will be substantial overlap between the population for this study, and for The Falls study (also presented at NCER).

Inclusion criteria: Adult patients presenting to one of the emergency department after sustaining blunt trauma to the head within 48 hours and initial emergency department GCS score of 13 or greater. Patient must have taken an oral or subcutaneous anticoagulant within the last 4 days (including warfarin, apixaban, rivaroxaban, edoxaban, dabigatran, fondaparinux, low molecular weight heparin or subcutaneous unfractionated heparin).

Exclusion criteria: these are deliberately kept to a minimum and are age <16, head injury >48 hours ago and GCS <13.

Standardized assessment

All patients will undergo head CT scanning in the emergency department. The certified staff radiologist final report will be used to determine study outcome.

Standardized patient follow-up

We will follow each patient for 42 days (6 weeks) to identify patients who develop a delayed bleed. This will be done by electronic medical record at the index hospital site and at the regional neurosurgical centre.

Outcomes and definitions

The primary outcome will be the diagnosis of clinically relevant intracranial bleeding (extradural, subdural, subarachnoid, intracerebral or intraventricular). The definition of ‘clinically relevant intracranial bleeding’ will be established by consensus, by an expert group consisting of a neurosurgeons, neurologists and thrombosis physicians.

Secondary outcomes will include intracranial bleeding with hospital admission, neurosurgical intervention and 6-week mortality.


We will report the post-test prevalence of clinically relevant intracranial bleeding among patients who are negative on Canadian CT head rule testing.

A secondary analysis will include a recursive partitioning analysis to develop a new clinical decision rule that identifies patients with a <0.5% post-test prevalence of clinically relevant intracranial bleeding.

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