What is the recommended antithrombotic therapy for patients post-Coronary Artery Bypass Grafting (CABG)?

Antithrombotic Therapy After Coronary Artery Bypass Grafting (CABG)

Low-dose aspirin (75-100 mg daily) is recommended lifelong after CABG, initiated as soon as there is no concern about bleeding postoperatively. 1

Standard Antithrombotic Approach Post-CABG

Aspirin Monotherapy

• Aspirin 75-100 mg daily is the cornerstone of post-CABG antithrombotic therapy 1, 2
• Should be continued until the day of CABG and restarted as soon as bleeding risk subsides, ideally within 24 hours after surgery 1
• Immediate postoperative administration of aspirin improves both early and late graft patency 3
• Lifelong continuation is recommended for all CABG patients 1, 2

Dual Antiplatelet Therapy (DAPT) Considerations

• DAPT (aspirin plus P2Y12 inhibitor) may be considered in selected patients at:
  • Higher risk of graft occlusion
  • Low bleeding risk 1
• DAPT has shown superior vein graft patency compared to aspirin alone, particularly with ticagrelor-based regimens 1
• However, DAPT increases bleeding risk (BARC 2-5 bleeds) without significant differences in mortality or major adverse cardiovascular events 1, 4

Patient-Specific Antithrombotic Strategies

For Patients with Recent Acute Coronary Syndrome (ACS)

• Resume P2Y12 inhibitor (preferably clopidogrel) plus aspirin to complete 12 months of DAPT 2
• Clopidogrel is the preferred P2Y12 inhibitor after CABG 2

For Patients with Atrial Fibrillation or Other OAC Indication

• Direct oral anticoagulant (DOAC) is preferred over vitamin K antagonist (unless contraindicated) 1, 2
• After initial period with triple therapy, transition to:
  • OAC plus clopidogrel for 6-12 months (depending on ischemic risk)
  • Followed by OAC alone 1
• Early cessation of aspirin (≤1 week) is recommended to reduce bleeding risk 1

Bleeding Risk Management

• Proton pump inhibitor is recommended for patients at increased risk of gastrointestinal bleeding 1
• Consider proton pump inhibitor when using any antithrombotic therapy, based on individual bleeding risk 1
• P2Y12 inhibitors should be discontinued prior to elective CABG:
  • Clopidogrel: ≥5 days before
  • Ticagrelor: ≥3 days before
  • Prasugrel: ≥7 days before 1, 2

Emerging Evidence and Considerations

• Platelet aggregation appears to be the key driver of graft thrombosis, as anticoagulant therapy alone has proven ineffective at reducing graft thrombosis 5
• Recent evidence suggests DAPT may have more protective effects in off-pump CABG compared to on-pump procedures 4, 6
• The benefit of DAPT must be carefully weighed against the increased bleeding risk 4, 5

Important Caveats

• Prasugrel should not be administered to patients with prior stroke or transient ischemic attack 2
• For patients with mechanical heart valves, DOACs are not indicated; vitamin K antagonists remain the standard 1
• Transient new-onset atrial fibrillation occurs in approximately one-third of post-CABG patients, but the optimal timing for anticoagulation initiation remains unclear 1

Remember that antithrombotic therapy is just one component of comprehensive secondary prevention after CABG. Optimal management of other cardiovascular risk factors, including lipids, blood pressure, and diabetes, is equally important for long-term outcomes.