Thrombelastography as a Predictive Tool for Thromboembolic Events After Extremity Trauma: A Secondary Analysis of PREVENT-CLOT.

Background: Venous thromboembolism (VTE) poses significant risk of morbidity and mortality in orthopaedic trauma patients. Thromboelastography (TEG) analysis has been demonstrated to provide value in demonstrating hypercoagulability and predicting the risk of post-injury VTE. The primary aim was to investigate if TEG analysis at the time of admission following severe extremity trauma predicts thromboembolic events. We hypothesized that previously described elevations in maximal amplitude (MA) on initial TEG would correlate with an increased risk of VTE. Methods: This was a secondary study of PREVENT CLOT, a multicenter, randomized trial that enrolled adult patients with an extremity fracture (from hip to midfoot or shoulder to wrist) treated operatively or any pelvic or acetabular fracture. TEG at admission was performed according to local protocols. The primary outcome of this analysis was postoperative VTE. We assessed the association between admission TEG values and VTE using bivariate and multivariable regression analyses. Statistical significance was set at p < 0.05. Results: Thousand one hundred eighty-three patients enrolled participants in the PREVENTion of CLots in Orthopedic Trauma (PREVENT CLOT) trial had TEG analysis performed on initial presentation. Of these patients, 47 (3.97%) had a symptomatic postoperative VTE at a median of 9 days (interquartile range, 4-18 days). There were no differences in VTE rates when examining MA of ≥65, ≥69, or ≥72 (p = 0.12, 0.21, and 0.19, respectively). However, on admission TEG, reaction time (R-time) was significantly higher among those who experienced a postoperative deep venous thrombosis (2.45 vs. 1.79, p < 0.01). After controlling for confounders, R-time of ≥2.0 was associated with a 2.1-fold increased odds of VTE (OR 2.13, 95% confidence interval 1.06-4.28, p < 0.001). Conclusion: In contrast to previous smaller retrospective studies, elevated admission-TEG MA values were not predictive of VTE following operative orthopaedic extremity trauma in this secondary analysis of a large multicenter prospective study. Our findings suggest that an increased R-time on the admission TEG, which is thought to be indicative of a longer time to form a clot, may be paradoxically associated with an increased VTE risk in orthopedic trauma patients. Level of Evidence: Level II. See Instructions for Authors for a complete description of levels of evidence.