Repeat head computed tomography for anticoagulated patients with an initial negative scan is not cost-effective
Borst J, Godat LN, Berndtson AE, et al. Surgery. 2021;170(2):623-627.
Guidelines and society opinions generally recommend head CT for older patients taking anticoagulants who present with head trauma, regardless of the mechanism. However, recommendations regarding the next steps are mixed, ranging from observation to repeat scanning to discharge.
According to the literature, the risk of delayed bleed is estimated to be between 0.3% and 6%, and the risk appears to be highest for patients taking warfarin and lowest for patients taking antiplatelet agents.
The authors of this study provide the largest, most comprehensive view on the topic to date, presenting data from a consecutive sample of patients taking anticoagulants in a 5-year period during which their local hospital protocol mandated a repeat head CT for all patients within 6 hours.
Antithrombotic medications included anticoagulants (warfarin, direct-acting oral anticoagulants [DOACs], heparin, or enoxaparin) and antiplatelet agents (aspirin, clopidogrel, prasugrel, ticagrelor, or aspirin/dipyridamole).
Although the exact chart-review methods are not described in full, the medical records were reviewed for evidence of clinical changes in neurologic status at the time of repeat head CT.
The authors identified 1,676 patients presenting with blunt head trauma and taking anticoagulants between 2014 and 2019. The initial head CT was negative in 82% of patients, the median age was 77 years, 54.5% of the patients were male, the median Glasgow Coma Scale score was 15 (range 14-15), and the most common mechanism of injury was fall (79%).
A total of 544 patients were taking antiplatelet agents (split nearly in half between aspirin and clopidogrel-like agents), and 1,003 were taking anticoagulants (40.6% warfarin and 26.9% DOACs; some patients were taking combinations).
Of the patients with negative initial head CTs, 12 (0.9%) developed a delayed bleed, 7 of whom were taking warfarin (1.3% of all patients taking warfarin) and 3 of whom were taking DOACs (1.1% of all patients taking DOACs).
No patients had a change in neurologic status, and no interventions were performed.
Although the confidence intervals were large, a statistically significant difference was observed in the mean international normalized ratio between patients taking warfarin who had a delayed bleed and those who did not (3.7 vs 2.4, respectively).
Some strengths of this study are that it is the largest on this topic to date, it included a large portion of patients taking DOACs, and it removed the potential for selection bias because all patients received a second CT, per hospital protocol. Most of the limitations are those common to chart-review-based study protocols, the absence of long-term follow-up on any patients, and all data coming from a single site.
EDITOR’S COMMENTARY: In this retrospective study from a hospital where all patients on anticoagulants with head trauma get a second CT, the bleed rate on the initial scan was 18%—a finding supporting the use of 1 scan for all comers. The observed delayed bleed rate was 0.9%, and none of the patients required any form of intervention. This study adds to the strong evidence refuting a mandate for a delayed CT after an arbitrary observation period. Return precautions are key, and patients with supratherapeutic international normalized ratios may deserve special consideration.
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