METHODS: We conducted a multicenter, double dummy, blinded, randomized controlled trial of patients recruited by convenience sampling in academic hospitals undergoing cardiac surgery with cardiopulmonary bypass. Between September 17, 2019, and November 28, 2023, a total of 3242 patients from 16 hospitals in 6 countries were randomly assigned (1:1 ratio) to receive either intravenous tranexamic acid (control) through surgery or topical tranexamic acid (treatment) at the end of surgery. The primary outcome was seizure, and the secondary outcome was red blood cell transfusion. After the last planned interim analysis, when 75% of anticipated participants had completed follow up, the data and safety monitoring board recommended to terminate the trial, and upon unblinding, the operations committee stopped the trial for safety.

RESULTS: Among 3242 randomized patients (mean age, 66.0 years; 77.7% male), in-hospital seizure occurred in 4 of 1624 patients (0.2%) in the topical group, and 11 of 1628 patients (0.7%) in the intravenous group (absolute risk difference, -0.5% [95% CI, -0.9 to 0.03]; P=0.07). Red blood cell transfusion occurred in 570 patients (35.1%) in the topical group and in 433 (26.8%) in the intravenous group (absolute risk difference, 8.3% [95% CI, 5.2-11.5]; P=0.007). The absolute risk difference in transfusion of ≥4 units of red blood cells in the topical group compared with the intravenous group was 8.2% (95% CI, 3.4-12.9).

CONCLUSIONS: Among patients undergoing cardiac surgery, topical administration of tranexamic acid resulted in an 8.3% absolute increase in transfusion without reducing the incidence of seizure, compared with intravenous tranexamic acid.