Tranexamic acid reduces bleeding risk during coronary artery surgery: The ATACAS trial

1. Tranexamic acid demonstrated a significantly lower risk of bleeding complications and transfusion requirements compared to placebo in patients undergoing coronary artery surgery.

2. There was no significant increase in the risk of death or thrombotic complications associated with the use of tranexamic acid, but there was a significantly higher risk of postoperative seizure.

Evidence Rating Level: 1 (Excellent) 

Study Rundown: There are a number of complications that can occur following coronary artery surgery, including bleeding, that may require a return to the operating room. Tranexamic acid is an antifibrinolytic medication often used in this setting; however, its possible prothrombotic effects and association with postoperative seizures may outweigh the benefits. This study investigated the effects of tranexamic acid on death, thrombotic complications, and bleeding-related events in at-risk patients undergoing both on- and off-pump coronary artery surgery. The primary outcome – a composite of death and thrombotic complications within 30 days – was not significantly different between the tranexamic acid and placebo groups. Among the secondary outcomes, tranexamic acid demonstrated a significantly decreased risk of reoperation due to hemorrhage and decreased transfusion requirements, but also a significantly increased risk of postoperative seizures. The risk of seizures did not differ after dose reduction.

This was a randomized, double-blinded, multicenter trial that suggests the use of tranexamic acid may significantly reduce bleeding and total blood products needed for coronary artery surgery. Limitations included an underpowered analysis of the dose effect on postoperative seizures, enrollment of only a small number of patients at highest risk for bleeding or thrombosis, and anesthesiologist knowledge of some of the treatment-group assignments.

Click to read the study, published today in NEJM

Relevant Reading: Stopping vs. continuing aspirin before coronary artery surgery

In-Depth [randomized controlled trial]: This randomized trial used a 2-by-2 factorial design to randomly assign patients scheduled for coronary-artery surgery to tranexamic acid (n = 2311) or placebo (n = 2320) and aspirin or placebo (the results of the aspirin comparison were previously published). The primary outcome was a composite of death and thrombotic events (MI, stroke, pulmonary embolism (PE), renal failure, or bowel infarction) within 30 days. Secondary outcomes included death, nonfatal MI, stroke, PE, renal failure, bowel infarction, reoperation due to hemorrhage or tamponade, and transfusion requirements. Postoperative seizures were added as a safety outcome during the course of the trial.

Death or thrombotic complications occurred in 16.7% of patients in the tranexamic acid group vs. 18.1% in placebo (RR 0.92; 95%CI, 0.81 to 1.05; p = 0.22). The rates of death, stroke, PE, renal failure, and bowel infarction were similar in both groups. Among bleeding related outcomes, tranexamic acid had significantly fewer patients who experienced blood loss during surgery (p < 0.001), total blood products transfused (p < 0.001), and patients requiring transfusion (p < 0.001). Major hemorrhage or tamponade leading to reoperation was significantly reduced in the tranexamic acid group (1.4% vs. 2.8%; p = 0.001). Postoperative seizures occurred in 0.7% of patients in the tranexamic acid group vs. 0.1% in placebo (RR 7.60; 95%CI 1.80 to 68.70; p = 0.002). Study outcomes, including seizure risk, did not change following a dose reduction of tranexamic acid (100 mg to 50 mg) that occurred mid-way through the trial.

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