University of Colorado researchers reported that adding exogenous tissue plasminogen activator (tPA) to thrombelastography (TEG) and combining results of this testing with international normalized ratio (INR) better identifies trauma patients in need of massive transfusion in comparison to standard predictors (J Am Coll Surg 2017; doi.org/10.1016/j.jamcollsurg. 2017.02.018). The findings suggest that the tPA-TEG and INR combination could lead to more personalized trauma care and make better use of scarce blood bank resources, according to the authors.
Trauma-induced coagulopathy defined as INR >1.5 results from complex mechanisms, including increasing tPA activity and resulting hyperfibrinolysis as patients progress to hemorrhagic shock. The investigators hypothesized that adding tPA to patients’ blood samples would predict patients at high risk of progressing to hyperfibrinolysis.
The study involved 324 consecutive patients who met criteria for the highest level of activation at Denver Health Medical Center’s Level I trauma center. Overall, 17% required massive transfusion, and the mortality rate of this study cohort was 13%.
In addition to standard TEG, the authors assessed lower-dose tPA-TEG and higher-dose tPA-TEG for the TEG time to maximum amplitude and lysis 30 minutes after maximum amplitude (LY30) as parameters for predicting massive transfusion. They also considered a variety of traditional clinical scores.
The investigators found that low-dose tPA-TEG LY30 had the best performance of all assays and scores, with an area under the receiver operating characteristic of 0.86 at its optimal thresholds for predicting massive transfusion. However, this assay took 50 minutes to return results.
Considering tPA-TEG with INR results improved the predictive power of identifying patients who needed transfusion by about 40% and identified 97% of patients who did not require blood products.