The Aspirin and Tranexamic Acid for Coronary Artery Surgery (ATACAS) trial was a multicentre, double-blind trial in which patients who were scheduled to undergo coronary-artery surgery and were at increased risk for complications were randomly assigned to receive tranexamic acid (TA) or placebo and aspirin or placebo. The results of the aspirin comparison have been published previously. The authors now report the results of the TA comparison.

A total of 4662 patients were enrolled and underwent coronary artery bypass grafting (CABG), on- or off-pump, with or without valve replacement or other procedures. The majority of patients (over 75%) underwent isolated CABG surgery. Patients received 100 mg/kg of TA or placebo 30 min after induction of anaesthesia. The dose was reduced to 50 mg/kg after enrollment of the first 1392 patients. The primary outcome was a composite of death and thrombotic events within 30 days after surgery.

The incidence of death or thrombotic complications was not different between TA or placebo (16.7 vs. 18.1%, respectively). Patients in the TA group had less bleeding complications and required less transfusions. The need for reexploration for bleeding or tamponade was halved in the TA group compared to placebo (1.4 vs. 2.8% respectively; P < 0.05). Seizures were significantly more frequent in the TA group compared to placebo. The difference in the incidence of seizures was significant for open chamber surgery but not for isolated CABG surgery. Overall, the results are not surprising. It had been shown before that ‘high-dose’ TA effectively reduces bleeding in cardiac surgery (Sigaut S et al. Anesthesiology 2014;120:590-600). However, the issue of seizures remains troublesome as, unfortunately, seizures occur in patients who may be most in need of an effective blood-sparing agent, i.e. those who undergo more complex, open-chamber operations in conjunction with CABG surgery. It remains to be demonstrated that somewhat lower doses and an infusion, such as those used in BART trial (Fergusson DA et al. N Engl J Med 2008;358:2319-31) aiming to obtain and maintain effective antifibrinolytic concentrations of TA are also efficacious and safer than a single bolus dose.

– Jean-François Hardy