Tranexamic acid (TXA) is routinely administered in children undergoing cardiac surgery. Several trials have reported that its use could decrease blood loss and transfusion requirements, but other authors have observed an increased, dose-dependent incidence of seizures. A huge variability in dosage schemes is observed between studies performed in children undergoing cardiac surgery. This variability can easily be explained by the lack of TXA pharmacokinetic (PK) studies in the pediatric population. In addition, no study has assessed the therapeutic concentration of TXA needed to prevent and/or inhibit fibrinolysis.
In this study, the authors first compared the effects of a continuous TXA infusion or discontinuous TXA administration with a control group on different markers of fibrinolysis (D-dimers, tPA, tPA-PAI-1 complexes, fibrinogen and fibrin monomer concentrations). They observed that either a continuous TXA infusion or repeated TXA boluses inhibited fibrinolysis compared to the control group.
The authors took advantage of a PK study (Grassin-Delyle S et al. Anesthesiology 2013;118:853-62) to simultaneously investigate the effect of TXA on fibrinolysis parameters. Unfortunately, they did not correlate their published results with the plasmatic concentrations observed in the PK study. Also, this study did not compare a PK-based dosage scheme with ‘usual’ doses. Finally, the authors studied a small and heterogeneous population that included different proportions of children with cyanotic and non-cyanotic diseases in each group.
In conclusion, this interesting study first compared the effects of two TXA dose regimens on fibrinolysis. Further studies will be needed to study the effects of a PK-based dosage scheme compared to a ‘standard’ dose regimen on fibrinolysis. Adequately powered studies will be needed to assess those factors that influence the effect of TXA on the inhibition of fibrinolysis (e.g. cyanotic vs. non-cyanotic disease, age, etc.).
– David Faraoni