Does tranexamic acid (TXA) affect graft potency after coronary artery bypass grafting (CABG)?

Tranexamic Acid Does Not Affect Coronary Artery Bypass Graft Patency

Tranexamic acid (TXA) effectively reduces postoperative bleeding in CABG surgery without negatively affecting graft patency. While TXA has been extensively studied for its hemostatic benefits in cardiac surgery, there is no evidence in current guidelines or research suggesting that it adversely affects coronary graft patency after CABG.

Effects of TXA in CABG Surgery

Benefits on Bleeding Reduction

• TXA significantly reduces postoperative bleeding in both on-pump and off-pump CABG:
  • Reduces chest tube drainage in the first 24 hours by approximately 206 ml 1
  • Decreases postoperative blood loss by 43% in on-pump CABG and 27% in off-pump CABG 2
  • Lowers the incidence of reoperation for bleeding (relative risk 0.46) 1
  • Reduces the need for allogeneic blood transfusions (relative risk 0.64) 1

Safety Profile Regarding Graft Patency

• No evidence in current ACC/AHA guidelines suggests TXA affects coronary graft patency 3
• Multiple randomized controlled trials evaluating TXA in CABG have not reported any adverse effects on graft function or patency 1, 4, 2, 5
• TXA does not significantly increase the risk of prothrombotic complications that could affect graft patency:
  • No significant increase in myocardial infarction (RR 0.90) 1
  • No significant increase in cerebrovascular accidents (RR 0.93) 1
  • No significant increase in mortality (RR 0.82) 1

Graft Assessment Methods in CABG

While TXA itself doesn't appear to affect graft patency, it's worth noting that proper assessment of graft function is critical in CABG procedures:

• Transit time flow measurement (TTFM) and intraoperative fluorescence imaging (IFI) are commonly used techniques to assess graft function and anatomy 3
• TTFM has demonstrated clinical value in predicting graft failure at 3,6, and 12 months post-CABG 3
• Inadequate graft flow (defined by pulsatility index >5 on TTFM) is an independent predictor of major adverse cardiac events 3

Important Considerations When Using TXA in CABG

Dosing

• Effective dosing regimens from studies include:
  • 10 mg/kg loading dose followed by 1 mg/kg/hr for 5 hours 4
  • 1 g bolus before skin incision followed by 400 mg/hr continuous infusion 2

Potential Side Effects

• TXA may increase the risk of postoperative seizures (RR 6.67) 1
• No significant effect on acute renal insufficiency has been observed 1

Contraindications

• TXA should be used with caution in patients with additional prothrombotic risk factors 6
• While not specifically contraindicated in CABG patients, the combination of TXA with certain medications (such as drospirenone) may increase thrombotic risk 6

Conclusion

Based on the available evidence, TXA is an effective agent for reducing bleeding complications in CABG surgery without compromising graft patency. The benefits of reduced blood loss and decreased transfusion requirements appear to outweigh potential risks in most patients undergoing CABG.