Point-of-care Measurement of the Antifibrinolytic Activity of Tranexamic Acid in Cardiac Surgery

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.

Conditions

• Antifibrinolytic Agents

Interventions

DRUG

Tranexamic acid bolus 20 mg/kg

Bolus of tranexamic acid in the standard dose group

DRUG

Tranexamic acid bolus 10 mg/kg

Bolus of tranexamic acid in the low dose group

DRUG

Tranexamic acid bolus 1 mg/kg

Bolus of tranexamic acid in the low dose group (to add into the CPB prime)

DRUG

Tranexamic acid continuous infusion of 1 mg/kg/h in the low dose group

Tranexamic acid continuous infusion during the procedure

Sponsors & Collaborators

• Insel Gruppe AG, University Hospital Bern

  lead OTHER

Principal Investigators

• Annegret Kauert-Willms, MD · University Hospital Berne

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

90 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-12-15

Primary Completion

2025-12-31

Completion

2026-12-31

Countries

• Switzerland

Study Locations