Tranexamic Acid in Cardiac Surgery: Efficacy and Safety
Tranexamic acid is strongly recommended during on-pump cardiac surgery to reduce bleeding complications, and it does not increase the risk of graft thrombosis in CABG patients. 1
Bleeding Reduction Benefits
The Enhanced Recovery After Surgery (ERAS) Society provides a Class I, Level A recommendation for tranexamic acid or epsilon aminocaproic acid during on-pump cardiac surgical procedures. 1 This represents the highest level of evidence-based recommendation.
Key Efficacy Data
In a large randomized trial of patients undergoing coronary revascularization, tranexamic acid significantly reduced total blood products transfused and major hemorrhage or tamponade requiring reoperation. 1
A 2017 multicenter trial (ATACAS) involving 4,631 cardiac surgery patients demonstrated that tranexamic acid reduced blood product transfusions from 7,994 units (placebo) to 4,331 units (tranexamic acid group), and decreased reoperation for bleeding from 2.8% to 1.4%. 2
Local application of tranexamic acid (1 gram in pericardial/mediastinal cavities) reduced 24-hour blood loss from 1,040 ml to 626 ml in CABG patients, with significantly less platelet transfusion required. 3
Graft Thrombosis Risk: Evidence Shows Safety
Multiple high-quality studies demonstrate that tranexamic acid does not increase graft thrombosis risk in CABG patients.
Direct Graft Patency Evidence
A prospective randomized trial of 312 CABG patients using MRI assessment found no difference in early saphenous vein graft patency between tranexamic acid (85.2%) and placebo (87.2%) groups (p=0.50). 4 This study specifically evaluated the concern about graft thrombosis and found it unfounded.
A systematic review of 12 high-quality studies concluded that although no study directly examined vein graft patency with tranexamic acid, no randomized studies raised safety concerns regarding thrombotic complications. 5
Broader Thrombotic Safety Data
The ATACAS trial found no increased risk of the composite primary outcome (death and thrombotic complications including myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) at 30 days: 16.7% with tranexamic acid versus 18.1% with placebo (relative risk 0.92). 2
A 2025 meta-analysis of 216 trials involving 125,550 participants across all clinical settings found no evidence of increased thromboembolic complications with tranexamic acid. 6
In trauma patients (20,211 participants), tranexamic acid actually showed lower rates of thrombosis, especially myocardial infarction, compared to placebo. 6
Dosing Recommendations and Safety Considerations
Recommended Dosing
Maximum total dose should not exceed 100 mg/kg due to seizure risk at higher doses. 1
Low-dose protocol (15 mg/kg loading, 6 mg/kg/h infusion, 1 mg/kg CPB prime) is as effective as high-dose protocol (30 mg/kg loading, 15 mg/kg/h infusion, 2 mg/kg CPB prime) for bleeding reduction in primary CABG. 7
Important Safety Caveat
Seizure risk is increased with tranexamic acid use: 0.7% versus 0.1% in placebo (p=0.002). 2 This risk is dose-dependent, reinforcing the importance of adhering to the maximum 100 mg/kg total dose. 1
Dose reduction is mandatory in renal dysfunction as tranexamic acid is renally excreted, with higher risk of neurotoxicity in renal impairment. 8, 9
Clinical Algorithm for Use
For on-pump cardiac surgery (including CABG):
Administer tranexamic acid routinely unless contraindications exist (active thromboembolic disease, history of recent thrombosis, DIC). 1, 8, 9
Use low-dose protocol (15 mg/kg loading dose, 6 mg/kg/h infusion until end of surgery, 1 mg/kg in CPB circuit) to minimize seizure risk while maintaining efficacy. 7
Ensure total dose does not exceed 100 mg/kg. 1
Adjust dose in renal dysfunction to prevent neurotoxicity. 8, 9
Monitor for seizures postoperatively, particularly with higher doses. 2