Point-of-care Measurement of the Antifibrinolytic Activity of Tranexamic Acid in Cardiac Surgery
Status:
Recruiting
Trial end date:
2026-12-31
Target enrollment:
Participant gender:
Summary
Tranexamic acid (TXA) is a widely used antifibrinolytic agent that can reduce postoperative
blood loss and packed red blood cell transfusions during cardiac surgery. Previous (in-vivo)
studies have measured TXA plasma concentration and associated clinical effect (e.g. blood
loss). Patient blood management guidelines recommend the routine use of TXA in cardiac
surgery, especially for procedures with a high risk of bleeding.
A new point-of-care viscoelastic diagnostic assay (tissue plasminogen activator assay, TPA
assay) allows for a rapid determination of antifibrinolytic activity in a patient in the
operating room making TXA dose adjustment easily possible intraoperatively. Currently, there
is no consensus on the dosing of TXA and different protocols are used. Recommendations for
high doses (e.g. 30 mg/kg followed by 16 mg/kg per hour during cardiac surgery with 2 mg/kg
added to extracorporeal circulation) alternate with recommendations for low doses (e.g., 10
mg/kg followed by 1 mg/kg per hour for 12 hours).
Tranexamic acid administration increases the risk of postoperative seizure, a risk that
appears to be dose dependant. A recent meta-analysis suggests that a single TXA bolus of 20
mg/kg is sufficient to reduce postoperative blood loss and packed red blood cell transfusion
in patients undergoing aortocoronary bypass surgery. The calculations in the meta-analysis
were, however, based on a simulation of blood concentrations of TXA by a pharmacokinetic
model, so the results are subject to many uncertainties. The optimal TXA regimen for cardiac
surgery, both in terms of efficacy and safety therefore remains uncertain and requires
further investigation.
This study was invented to determine the actual levels of tranexamic acid in vivo to observe
antifibrinolytic activity during cardiac surgery up to 48 hours after termination of surgery.
The risk category is evaluated as risk category A as the study is a clinical trial examining
the effect of drugs that are already authorized for the clinical use.