Trauma Management: Minor Head Injury in Anticoagulated Patients
Anticoagulation by inhibition of platelets or coagulation cascades improves outcomes in patients at risk for acute coronary syndromes, cerebrovascular accidents, or embolic events. These benefits come at a price, though, of increased tendency toward bleeding, and impaired ability to mount a coagulation response at sites of hemorrhage. This is particularly dangerous for victims of head trauma, who may harbor small but steadily growing intracranial hematomas in the absence of outward signs. Two recent articles address this problem, and propose a protocol for managing minor head trauma in anticoagulated patients while minimizing risk of missed intracranial injury.
Nishijima DK, Offerman SR, Ballard DW, Vinson DR, Chettipally UK, Rauchwerger AS, Reed ME, Holmes JF. Immediate and delayed traumatic intracranial hemorrhage in patients with head trauma and preinjury warfarin or clopidogrel use. Ann Emerg Med 2012; 59(6), 460-8.
This is an observational cohort study done over a two-year period in six centers (two trauma centers and four community hospitals), that evaluated patients suffering a head injury while taking either clopidogrel or warfarin. The study’s aim was to identify the prevalence of immediate intracranial hemorrhage from each of these groups and evaluate the incidence of delayed intracranial hemorrhage up to two weeks after the original injury.
Included patients were greater than 18 years of age, used warfarin or clopidogrel within seven days preceding the injury, and suffered any blunt head trauma. Patients were excluded if they had concomitant use of both warfarin and clopidogrel.
A total of, 1,064 patients were included in the cohort analysis. Sevenhundred sixty-eight patients were warfarin users and 296 patients were clopidogrel users. The mechanism of injury was a ground level fall in 83%, a direct blow to the head in 6%, and a motor vehicle crash in 5%. Eighty-eight percent of patients had an initial GCS of 15 and 70% of patients displayed evidence of trauma above the clavicles.
The prevalence of immediate traumatic intracranial hemorrhage was higher in patients receiving clopidogrel (33/276; 12.0%; 95% CI 8.4% to 16.4%) than warfarin (37/724, 5.1%, 95% CI 3.6% to 7.0%; relative risk 2.31, 95% CI 1.48 to 3.63; p<0.001). Delayed traumatic intracranial hemorrhage was identified in 4 of 687 patients receiving warfarin (0.6%; 95% CI 0.2% to 1.5%), and 0 of 243 patients receiving clopidogrel (0%; 95% CI 0% to 1.5%).
This is an observational study and not all patients presenting with head trauma received a CT on initial evaluation. Differences between groups existed in that more patients on clopidogrel were taking aspirin, which may confound the higher rate of intracranial bleeding. No difference in the prevalence of initial intracranial hemorrhage was noted when the subgroup of clopidogrel patients not taking aspirin underwent subgroup analysis. Given the observational nature of the study, other unmeasurable differences may explain the difference in bleeding between the two groups. Also, inclusion in the study was based on recent warfarin use, rather than measured INR. Those patients taking warfarin but with nearly normal INRs were treated equally in this study to those with therapeutic warfarin levels, which may skew results toward lower incidence and prevalence of bleed.
The study is helpful in estimating the prevalence and incidence of immediate and delayed intracranial hemorrhage. There is a high rate of hemorrhage among users of both groups, suggesting that a noncontrasted head CT should be strongly considered in all such patients.
Menditto VG, Lucci M, Polonara S, Pomponio G, Gabrielli A. Management of minor head injury in patients receiving oral anticoagulation therapy: A prospective study of a 24-hour observation protocol. Ann Emerg Med 2012; 59(6), 451-5.
Patients suffering mild head injury while taking an oral anticoagulant medication pose a disposition dilemma to the emergency clinician. The authors of this study looked at whether a 24 hour observation protocol with repeat head CT improved the recognition of delayed intracranial bleeding.
The study was set up as a prospective observational cohort study at a Level-II trauma center in Italy. Patients were included if they were >14 years of age, were taking warfarin for therapeutic anticoagulation, had an injury severity score <15, had any head injury with a GCS of 14-15, and presented to the ED within 48 hours of injury. Patients were excluded if the first CT showed any evidence of intracranial bleeding or a depressed skull fracture.
Ninety-seven consecutive patients were enrolled after initial negative head CT. Ten patients abstained from the repeat head CT leaving 87 patients with repeat imaging. Five patients developed a delayed intracranial hemorrhage on the second CT; three required hospitalization and one required surgery. Two additional patients presented 2 and 8 days after finishing the observation protocol with symptomatic intracranial hemorrhage. Analysis of patient variables collected on a structured data form at the time of enrollment indicates that an INR greater than 3.0 confers a relative risk of 14 (95% CI: 4 to 49) for delayed intracranial hemorrhage.
This study sets the stage for establishing ED-based observation protocols for minor head trauma in patients on anticoagulation. Of note, none of the patients enrolled had a GCS of 14 or had used any other anticoagulant or antiplatelet agent. The limitations of the study are that this is a single site and the numbers of patients with delayed intracranial hemorrhage was not high and limited the ability to determine predictors of intracranial hemorrhage. Further studies need to evaluate the reproducibility of these results in a multicenter population and also investigate the optimal timing for repeat imaging.