A preliminary study of a new tranexamic acid dosing schedule for cardiac surgery.

Objective(s): The authors have developed an alternative dosing schedule for tranexamic acid that incorporates the effects of renal function on tranexamic acid concentrations. The objectives of this study were to determine if this new dosing schedule can achieve the desired plasma concentration of tranexamic acid and reduce intra- and interpatient variability in tranexamic acid plasma concentrations relative to the current dosing schedule.

Design: A prospective randomized trial.

Setting: A tertiary referral medical center hospital.

Participants: Cardiac surgery patients.

Interventions: Cardiac surgery patients were randomly assigned to receive the authors' standard tranexamic acid loading dosage of 10 mg/kg given over 20 minutes, followed by an infusion of 1 mg/kg/h (9 patients), or the new drug dosage schedule described later (11 patients).

Measurements And Main Results: Perioperative plasma tranexamic acid concentrations were measured using high-performance liquid chromatography. From repeated-measures analysis of variance, a significant (p < 0.001) time-by-treatment interaction effect was detected indicating that differences in mean tranexamic acid concentration between treatment groups were dependent on time period. Among patients receiving the standard dosing regimen, those with renal insufficiency had lower tranexamic acid concentration at 5 minutes on cardiopulmonary bypass (p = 0.003). For patients receiving the experimental regimen, the mean tranexamic acid concentration did not differ significantly at any time point between patients with and without renal insufficiency (p > 0.20 at all time points).

Conclusions: The new dosing protocol for tranexamic acid resulted in more consistent blood concentrations of tranexamic acid, but not stable tranexamic acid levels >20 microg/mL on cardiopulmonary bypass.