Changes in blood concentration of tranexamic acid in dialysis and non-dialysis patients undergoing cardiac surgery: a prospective observational cohort study.

The pharmacokinetics of tranexamic acid (TXA), used during cardiopulmonary bypass (CPB) surgery, in patients receiving maintenance hemodialysis remain unclear. This prospective study compared serum tranexamic acid (TXA) concentrations following bolus administration and subsequent intensive care unit (ICU) admission in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB), including those receiving maintenance hemodialysis and those not on dialysis. Participants received two TXA boluses: 1000 mg (500 mg for patients receiving hemodialysis) at procedure initiation and another 1000 mg (500 mg for patients receiving hemodialysis) after CPB withdrawal. Blood samples were collected at 30, 60, and 120 min, and after CPB weaning after the first dose; following the second dose; upon ICU admission; and at 4, 8, and 12 h post-ICU admission to measure TXA concentrations. A renal function-based simulation model was developed to optimize TXA dosing. Among 82 patients (74 without dialysis and 8 receiving hemodialysis), serum TXA concentrations were similar between groups until ICU admission. Following CPB withdrawal, patients receiving hemodialysis exhibited higher TXA concentrations than non-dialysis patients, despite receiving only half the total dose. TXA concentrations remained significantly higher in hemodialysis patients after ICU admission. Bolus administration effectively maintained antifibrinolytic TXA levels (> 10 µg/mL). The renal function-based model guides optimal TXA dosing strategies.