What is the recommended dose of aspirin (acetylsalicylic acid) for patients undergoing Coronary Artery Bypass Grafting (CABG)?

Aspirin Dosing for CABG Patients

Aspirin should be administered at a dose of 100 mg to 325 mg daily for patients undergoing coronary artery bypass grafting (CABG) surgery. 1

Preoperative Aspirin Management

• Preoperative administration: Aspirin (100-325 mg daily) should be administered to CABG patients preoperatively 1
• Continuation: If patients are already on aspirin therapy, it should be continued until surgery in most cases
• Bleeding risk consideration: While preoperative aspirin may increase bleeding risk, this is generally outweighed by the cardiovascular benefits 2
• Low-dose preference: Lower doses (81-100 mg) may minimize bleeding risk while maintaining efficacy 3

Postoperative Aspirin Management

Timing of Initiation

• If aspirin was not initiated preoperatively, it should be started within 6 hours after surgery 1
• Early initiation (within 6 hours) is critical to reduce saphenous vein graft closure 1
• Delaying aspirin initiation beyond 48 hours postoperatively results in loss of graft patency benefit 1

Dosing Recommendations

• Dose range: 100-325 mg daily is recommended by ACC/AHA guidelines 1
• Duration: Aspirin should be continued indefinitely after CABG 4
• Preferred dosing:
  • 75-100 mg daily is preferred by European guidelines to minimize bleeding while maintaining efficacy 4
  • 81 mg daily is commonly used in clinical practice and considered acceptable 1

Special Considerations

Dosing Frequency

• Once-daily dosing is standard practice
• Some evidence suggests that twice-daily dosing (e.g., 162 mg twice daily) may provide better platelet inhibition in the early postoperative period compared to once-daily dosing 5, 6
• Multiple daily dosing may overcome reduced platelet response seen after CABG surgery 6

Aspirin Resistance

• Transient aspirin hyporesponsiveness can occur after CABG surgery
• Higher doses or more frequent dosing may overcome this phenomenon 7
• Monitoring platelet function may be considered in high-risk patients

Dual Antiplatelet Therapy (DAPT)

• For patients with recent acute coronary syndrome, DAPT with aspirin plus a P2Y12 inhibitor for 12 months is recommended 4
• For stable coronary disease patients, aspirin monotherapy is standard, but adding clopidogrel for 12 months may improve vein graft patency 4

Potential Pitfalls and Caveats

• Avoid aspirin discontinuation: Stopping aspirin therapy after CABG increases risk of graft occlusion and adverse cardiovascular events
• Bleeding risk assessment: While bleeding risk is increased with aspirin, this is generally outweighed by cardiovascular benefits
• Dose considerations: Higher doses (325 mg) may increase bleeding risk without additional benefit compared to lower doses (81-100 mg) 3
• Enteric-coated formulations: May result in suboptimal platelet inhibition; non-enteric coated formulations are preferred 1

In summary, aspirin therapy at doses of 100-325 mg daily should be initiated preoperatively or within 6 hours after CABG surgery and continued indefinitely to optimize graft patency and reduce adverse cardiovascular events.