What is the recommended antiplatelet therapy regimen for patients post-coronary artery bypass graft (CABG)?

Post-CABG Antiplatelet Therapy Recommendations

Aspirin 75-100 mg daily should be started within 6 hours after CABG surgery and continued indefinitely as the cornerstone of post-CABG antiplatelet therapy for all patients. 1, 2

Primary Antiplatelet Recommendations

Immediate Post-CABG Period

• Aspirin 75-100 mg daily should be initiated as soon as there is no concern about bleeding, ideally within 24 hours after surgery 2
• Starting aspirin within 6 hours post-CABG has been shown to be safe without increasing bleeding risk 3
• For patients undergoing CABG after ACS, P2Y12 inhibitor therapy should be resumed postoperatively to complete 12 months of DAPT after ACS 1

Long-term Therapy Based on Clinical Context

1. Standard Post-CABG (No Recent ACS)

   • Aspirin 75-100 mg daily indefinitely (Class I recommendation) 1, 2
   • Consider adding clopidogrel for 12 months to improve vein graft patency (Class IIb recommendation) 1

2. Post-CABG After Recent ACS

   • P2Y12 inhibitor (preferably clopidogrel) plus aspirin should be resumed after CABG to complete a full 12-month course of DAPT after the ACS event 1
   • After 12 months, continue aspirin monotherapy indefinitely 1, 2

3. Post-CABG with Concurrent PCI

   • Follow duration of DAPT based on PCI recommendations 1
   • P2Y12 inhibitor therapy should be resumed postoperatively to complete the recommended duration 1

Choice of P2Y12 Inhibitor When Indicated

• Clopidogrel is the preferred P2Y12 inhibitor for post-CABG patients 2
• Ticagrelor may be considered in specific high-risk ACS patients post-CABG based on PLATO trial data showing reduction in cardiovascular mortality compared to clopidogrel 2
• Prasugrel should not be administered to patients with prior history of stroke or TIA 1

Special Considerations

Patients Requiring Oral Anticoagulation

• For patients with indications for oral anticoagulation (e.g., atrial fibrillation):
  • Direct oral anticoagulant (DOAC) is preferred over vitamin K antagonist unless contraindicated 2
  • After initial period with triple therapy, transition to OAC plus clopidogrel for 6-12 months, followed by OAC alone 2
  • For patients >12 months post-CABG who develop need for anticoagulation, OAC alone can be used 1

Bleeding Risk Management

• Proton pump inhibitor is recommended for patients at increased risk of gastrointestinal bleeding when using antiplatelet therapy 2
• Recent evidence suggests that dual antiplatelet therapy increases bleeding risk without improving outcomes in some populations 4
• In a Nordic trial, ticagrelor plus aspirin did not reduce the composite endpoint of death, MI, stroke, or repeat revascularization compared to aspirin alone, but increased bleeding risk 4

Important Caveats

• The benefit of DAPT appears most pronounced in the first year after CABG, particularly for improving vein graft patency 1, 2
• Benefit/risk ratio should be carefully considered, as recent evidence suggests increased bleeding without improved outcomes with more intensive antiplatelet regimens in some populations 4, 5
• For patients undergoing subsequent surgery, early cessation of aspirin (≤1 week) is recommended to reduce bleeding risk 2
• P2Y12 inhibitors should be discontinued prior to elective surgery: clopidogrel ≥5 days, ticagrelor ≥3 days, and prasugrel ≥7 days before 2

The evidence consistently supports aspirin as the foundation of post-CABG antiplatelet therapy, with the addition of P2Y12 inhibitors in specific clinical scenarios, particularly following ACS or when improved vein graft patency is a priority in high-risk patients.