ABSTRACT
BACKGROUND: Warfarin is associated with poor outcomes after trauma, an effect correlated with elevations in the international normalized ratio (INR). In contrast, the novel oral anticoagulants (NOAs) have no validated laboratory measure to quantify coagulopathy. We sought to determine if use of NOAs was associated with elevated activated partial thromboplastin time (aPTT) or INR levels among trauma patients or increased clotting times on thromboelastography (TEG). METHODS: This was a post-hoc analysis of a prospective observational study across 16 trauma centers. Patients on dabigatran, rivaroxaban, or apixaban were included. Laboratory data were collected at admission and after reversal. Admission labs were compared between medication groups. Traditional measures of coagulopathy were compared with TEG results using Spearman's rank coefficient for correlation. Labs before and after reversal were also analyzed between medication groups. RESULTS: 182 patients were enrolled between June 2013 and July 2015: 50 on dabigatran, 123 on rivaroxaban, and 34 apixaban. INR values were mildly elevated among patients on dabigatran (median 1.3, IQR 1.1-1.4) and rivaroxaban (median 1.3, IQR 1.1-1.6) compared with apixaban (median 1.1, IQR 1.0-1.2). Patients on dabigatran had slightly higher than normal aPTT values (median 35, IQR 29.8-46.3), whereas those on rivaroxaban and apixaban did not. Fifty patients had TEG results. The median values for R, alpha, MA and lysis were normal for all groups. Prothrombin time (PT) and aPTT had a high correlation in all groups (dabigatran p=0.0005, rivaroxaban p<0.0001, and apixaban p<0.0001). aPTT correlated with the R value on TEG in patients on dabigatran (p=0.0094) and rivaroxaban (p=0.0028) but not apixaban (p=0.2532). Reversal occurred in 14%, 25%, and 18% of dabigatran, rivaroxaban, and apixaban patients, respectively. Both traditional measures of coagulopathy and TEG remained within normal limits after reversal. DISCUSSION: Neither traditional measures of coagulation nor TEG were able to detect coagulopathy in patients on NOAs. LEVEL OF EVIDENCE: Level IV.
ABSTRACT
BACKGROUND: The number of anticoagulated trauma patients is increasing. Trauma patients on warfarin have been found to have poor outcomes, particularly after intracranial hemorrhage (ICH). However, the effect of novel oral anticoagulants (NOAs) on trauma outcomes is unknown. We hypothesized that patients on NOAs would have higher rates of ICH, ICH progression, and death compared with patients on traditional anticoagulant and antiplatelet agents. METHODS: This was a prospective observational trial across 16 trauma centers. Inclusion criteria was any trauma patient admitted on aspirin, clopidogrel, warfarin, dabigatran, rivaroxaban, or apixaban. Demographic data, admission vital signs, mechanism of injury, injury severity scores, laboratory values, and interventions were collected. Outcomes included ICH, progression of ICH, and death. RESULTS: A total of 1,847 patients were enrolled between July 2013 and June 2015. Mean age was 74.9 years (SD ± 13.8), 46% were female, 77% were non-Hispanic white. At least one comorbidity was reported in 94% of patients. Blunt trauma accounted for 99% of patients, and the median Injury Severity Score was 9 (interquartile range, 4-14). 50% of patients were on antiplatelet agents, 33% on warfarin, 10% on NOAs, and 7% on combination therapy or subcutaneous agents.Patients taking NOAs were not at higher risk for ICH on univariate (24% vs. 31%) or multivariate analysis (incidence rate ratio, 0.78; confidence interval 0.61-1.01, p = 0.05). Compared with all other agents, patients on aspirin (90%, 81 mg; 10%, 325 mg) had the highest rate (35%) and risk (incidence rate ratio, 1.27; confidence interval, 1.13-1.43; p < 0.001) of ICH. Progression of ICH occurred in 17% of patients and was not different between medication groups. Study mortality was 7% and was not significantly different between groups on univariate or multivariate analysis. CONCLUSION: Patients on NOAs were not at higher risk for ICH, ICH progression, or death. LEVEL OF EVIDENCE: Prognostic/epidemiologic study, level III.