Authors: Rachel Evans, Gordon Fuller, Tom Roberts, Dan Horner, Sue Mason / Codes: HAP29 & CC2O / Published: 28/08/2018
There are head injuries and head injuries in emergency medicine. A head injury on anticoagulation has long been thought to be the latter
But is it? We have worried for a long time about any head injury on warfarin, and a variety of management pathways have been introduced alongside bespoke NICE guidelines suggesting imaging for all. However, not all anticoagulants are cut from the same cloth. The Direct Oral Anticoagulant agents in particular have recently shown an improved mortality profile following intracranial bleeding, when compared to traditional agents 1. We still lack evidence as to how these new drugs affect the risk associated with a minor head injury. The increasing use of DOACs, and the increasing age of the population using them, make this a pressing issue.
Head injury is a common reason for attending the emergency department, responsible for up to 500,000 UK attendances and 2.8 million US ED attendances, hospitalisations and deaths each year 2,3. Patients taking anticoagulant medication have an increased risk of bleeding after injury, but the risk of intracranial bleed for head injured patients taking direct oral anticoagulants (DOACs) is not known. Current international head injury clinical decision rules recommend CT scans for all patients taking DOACs regardless of their symptoms and signs 4. A systematic review of the management of these patients shows that evidence in this area is very limited 5.
Good quality prospective research is required in order to determine the risk of adverse outcome in these patients and identify which patient factors are associated with increased risk of adverse outcome. It may be possible to save patients’ time, radiation exposure and resources in the ED for patients who are found to be at low risk of adverse outcome.
The findings from this research will inform robust clinical guidance for the investigation and management of head inured patients taking DOACs.
The team from Sheffield have already had success delivering the AHEAD study, which looked at head injury in >3500 warfarinised patients at over 30 sites 6. The results demonstrated a low incidence of adverse events in those patients with GCS 15 and absent symptoms (2.7% (95% CI 2.1 to 3.6). Risk of adverse outcome was increased in the presence of vomiting, amnesia, headache or loss of consciousness. It remains to be seen whether these findings can be extrapolated to those on DOAC therapy, or whether the adverse event rate is even lower.
What is AHEAD2 planning to look at?
This study aims to identify the risk of adverse outcome for patients who have head injuries when taking DOACs who have GCS = 14 or 15 on assessment in the ED. The secondary objective is to identify patient risk factors which are associated with adverse outcome, and which may be used in a clinical decision rule for the management of these patients.
Eligible patients will be adults who present to the ED following head injury, who have GCS = 14 or 15 and are already taking a DOAC medication (Apixaban, Dabigatran, Edoxaban, Rivaroxaban).
Head injury is defined as non-penetrating trauma above the neck and adverse outcome is defined as one or more of death, neurosurgery, CT abnormality attributable to the injury and/or ED re-attendance with injury-related complication.
What are the specific aims of this project?
This will be a multicentre, prospective observational study taking place in as many UK-wide EDs as possible. The more departments, the more patients and the higher the quality of results! The required sample size is currently being determined with a pilot study.
All consecutive eligible patients in participating departments will be identified and flagged using codes within the departments patient management software.
The primary outcome will be calculating the proportion of adverse outcomes in the recruited population and the 95% confidence interval of this proportion.
The association of risk factors with outcome will be analysed using linear regression and whilst controlling for age, sex and hospital attended.
What will this study add for patients?
This study will provide accurate descriptors of risk and high-risk characteristics for adverse events following minor head injury in anticoagulated patients. This evidence is essential to allow informed decision making and appropriate safety netting. In many centres these patients undergo immediate and/or delayed brain imaging, resulting in radiation, delays to discharge and often hospital admission with associated iatrogenic risk. The data from this study could be used to generate accurate risk estimates to inform shared decision making, and educational materials to highlight high risk features.
What will this study add for clinicians?
This study should provide insight into genuine risk features of those patients on DOAC therapy with a head injury, allowing clinicians to make rational and evidence-based decisions regarding investigation. It will also support the development of robust pathways which can assist flow through departments and ensure elderly patients are not kept in hospital unnecessarily, in view of associated risks.
What is the timeline for this project?
The project is in the development / funding stage and is likely to be open for a long time. As such, TERN is simply opening up a dialogue with the team at Sheffield currently, in the hope that when they successfully achieve funding for the project we can assist by providing trainee site investigators and willing collaborators. It goes without saying that this question is one of paramount importance to us all, is another James Lind Alliance priority topic, and also a top scorer at the recent TERN scoping exercise so clearly a priority question 7.
Watch this space and expect regular updates as the team at Sheffield progress the project.
Anything else I should know?
The Canadians are linking up with Sheffield on this project and aiming to collect similar datasets, thus increasing the generalisability of the work. They have a survey open if you are interested in telling them what type of things you would like to see in a decision rule.
We have had expressions of interest for the first TERN projects from over 100 trainees. Regional representatives have been appointed in your region who will be driving the process. But if you want more information on this study in particular, drop us a line at firstname.lastname@example.org. You can also look at the other Tiles for information on how to sign up to TERN and get on the mailing list.
School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK Emergency Department, Bristol Royal Infirmary, Bristol, UK
Emergency Department, Salford Royal NHS Foundation Trust, Manchester, UK
- Inohara T, Xian Y, Liang L, et al. Association of Intracerebral Hemorrhage Among Patients Taking Non-Vitamin K Antagonist vs Vitamin K Antagonist Oral Anticoagulants With In-Hospital Mortality. JAMA 2018; 319(5): 463-73.
- Kay A, Teasdale G. Head injury in the United Kingdom. World J Surg 2001; 25(9): 1210-20.
- Rutland-Brown W, Langlois JA, Thomas KE, Xi YL. Incidence of traumatic brain injury in the United States, 2003. J Head Trauma Rehabil 2006; 21(6): 544-8.
- Head Injury: Triage, Assessment, Investigation and Early Management of Head Injury in Infants, Children and Adults. London; 2007.
- Minhas H, Welsher A, Turcotte M, et al. Incidence of intracranial bleeding in anticoagulated patients with minor head injury: a systematic review and meta-analysis of prospective studies. Br J Haematol 2018.
- Mason S, Kuczawski M, Teare MD, et al. AHEAD Study: an observational study of the management of anticoagulated patients who suffer head injury. BMJ Open 2017; 7(1): e014324.
- Smith J, Keating L, Flowerdew L, et al. An Emergency Medicine Research Priority Setting Partnership to establish the top 10 research priorities in emergency medicine. Emerg Med J 2017; 34(7): 454-6.