Plasma tranexamic acid concentrations during cardiopulmonary bypass

Area of Science:

• Cardiovascular Surgery
• Pharmacology
• Anesthesiology

Background:

• Tranexamic acid is used to reduce bleeding post-cardiac surgery.
• There is significant variability in recommended dosing and limited data on plasma concentrations during cardiopulmonary bypass (CPB).
• The in vitro inhibitory concentration for fibrinolysis is 10 microg/mL.

Purpose of the Study:

• To measure perioperative plasma concentrations of tranexamic acid during CPB.
• To evaluate the efficacy of a specific dosing regimen in achieving inhibitory concentrations.
• To investigate the impact of renal function on drug levels.

Main Methods:

• Twenty-one patients undergoing cardiac surgery received an initial dose of 10 mg/kg tranexamic acid followed by a 1 mg/kg/h infusion.
• Plasma concentrations were measured using high-performance liquid chromatography at various time points.
• Patient data, including creatinine levels, were analyzed for correlations with drug concentrations.

Main Results:

• Plasma tranexamic acid concentrations remained above the 10 microg/mL inhibitory threshold throughout CPB.
• Mean concentrations ranged from 37.4 microg/mL post-bolus to 17.7 microg/mL one hour after discontinuation.
• Patients with renal insufficiency exhibited higher tranexamic acid concentrations, with a significant interaction between time and creatinine levels.

Conclusions:

• The studied tranexamic acid regimen produces plasma concentrations sufficient to inhibit fibrinolysis during CPB.
• Dosing adjustments for tranexamic acid may be necessary in patients with impaired renal function.
• Further research should focus on optimizing tranexamic acid dosing in specific patient populations.