What is the recommended use of Tranexamic Acid (TXA) in Off-Pump Coronary Artery Bypass Grafting (OPCABG)?

Tranexamic Acid Use in Off-Pump Coronary Artery Bypass Grafting (OPCABG)

Tranexamic acid (TXA) is strongly recommended for use in off-pump coronary artery bypass grafting procedures to reduce perioperative blood loss and transfusion requirements. 1

Dosing and Administration

The optimal TXA protocol for OPCABG includes:

• Loading dose: 10-15 mg/kg IV at induction of anesthesia 2, 3
• Maintenance dose: 1-2 mg/kg/hour until the end of surgery 1, 3
• Maximum total dose: Should not exceed 100 mg/kg to minimize seizure risk 1

Evidence Supporting TXA Use in OPCABG

TXA has demonstrated significant benefits in OPCABG:

• Reduces 24-hour postoperative blood loss by approximately 50% (352ml vs 602ml) 2
• Decreases overall risk of allogeneic blood component transfusion by 53% (risk ratio = 0.47) 4
• Reduces packed red blood cell transfusion requirements by 49% (risk ratio = 0.51) 4
• Maintains these benefits even when used in combination with cell salvage techniques 5

Safety Profile

• No significant increase in thromboembolic events (myocardial infarction, stroke, or pulmonary embolism) has been observed with TXA use in OPCABG 4
• Lower doses (15 mg/kg loading followed by 6 mg/kg/h) appear equally effective as higher doses (30 mg/kg loading followed by 15 mg/kg/h) with potentially fewer side effects 6
• Total doses exceeding 100 mg/kg should be avoided due to increased seizure risk 1

TXA as Part of a Comprehensive Blood Conservation Strategy

TXA should be incorporated into a multimodal approach to blood conservation in OPCABG:

1. Preoperative management:

   • Withhold clopidogrel and ticagrelor for at least 5 days before elective OPCABG 1
   • Withhold prasugrel for at least 7 days before elective OPCABG 1
   • For urgent/emergent OPCABG in patients on antiplatelet therapy, TXA is particularly valuable as part of the hemostatic strategy 7

2. Intraoperative strategies:

   • Administer TXA at induction and maintain throughout surgery 2, 3
   • Consider cell salvage techniques in conjunction with TXA 5
   • Maintain hematocrit >19% and mean arterial pressure >60 mmHg in patients with preexisting renal dysfunction 7

3. Postoperative monitoring:

   • Continue monitoring for bleeding and consider additional TXA if significant bleeding persists
   • Measure biomarkers of myonecrosis in the first 24 hours after OPCABG 7

Clinical Pitfalls and Considerations

• TXA is preferred over aprotinin, which has been associated with increased risk of renal failure, MI, heart failure, stroke, and reduced long-term survival 7
• For patients with renal dysfunction, off-pump CABG with TXA may be particularly beneficial to reduce acute kidney injury risk 7
• TXA should be used with caution in patients with massive hematuria (risk of ureteric obstruction) and in patients on oral contraceptive pills (risk of thrombosis) 7
• TXA is contraindicated in disseminated intravascular coagulation 7

By incorporating TXA into standardized OPCABG protocols, clinicians can significantly reduce bleeding complications and transfusion requirements, ultimately improving patient outcomes.