What is the recommended Dual Antiplatelet Therapy (DAPT) regimen and duration for a patient undergoing coronary artery bypass surgery with 3 vessel coronary heart disease?

DAPT Therapy After Coronary Artery Bypass Surgery for 3-Vessel Coronary Heart Disease

For patients undergoing coronary artery bypass surgery with 3-vessel coronary heart disease, aspirin monotherapy is the standard approach, but dual antiplatelet therapy (DAPT) with aspirin plus clopidogrel for 12 months may be reasonable to improve vein graft patency.

Antiplatelet Recommendations Based on Clinical Context

For Stable Coronary Artery Disease Patients:

• Aspirin therapy:

  • Start aspirin 75-100 mg daily within 6 hours postoperatively if not already taking it 1
  • Continue aspirin indefinitely 1

• DAPT consideration:

  • Adding clopidogrel to aspirin for 12 months after CABG may be reasonable to improve vein graft patency (Class IIb recommendation) 2, 1
  • Current guidelines note there is insufficient data to strongly recommend DAPT in stable CAD patients undergoing CABG 2

For Patients with Recent Acute Coronary Syndrome:

• DAPT is strongly recommended:
  • Aspirin 75-100 mg daily indefinitely 2, 1
  • P2Y12 inhibitor (preferably clopidogrel in post-CABG setting) for 12 months 2, 1
  • Resume P2Y12 inhibitor postoperatively as soon as deemed safe 2

Medication Selection and Dosing

Aspirin:

• Dose: 75-100 mg daily (low-dose preferred to minimize bleeding while maintaining efficacy) 2, 1
• Timing: Start or resume within 6 hours after surgery 1
• Duration: Indefinite 1

P2Y12 Inhibitor:

• Agent of choice: Clopidogrel is the preferred P2Y12 inhibitor after CABG 2, 1
• Dose: 75 mg daily 2
• Duration:
  • 12 months for patients with recent ACS (Class I recommendation) 2, 1
  • 12 months may be reasonable for stable CAD patients to improve graft patency (Class IIb recommendation) 2, 1

Evidence Supporting DAPT After CABG

Recent evidence suggests DAPT with clopidogrel plus aspirin as secondary prevention after CABG is associated with:

• Reduced risk of major adverse cardiovascular and cerebrovascular events within 6 months compared to aspirin monotherapy 3
• No significant increase in major bleeding 3

Important Considerations and Caveats

• Bleeding risk assessment: DAPT increases bleeding risk compared to aspirin alone 2, 4
• Patient-specific factors: Consider age, weight, comorbidities, and concomitant medications that may increase bleeding risk 5
• Monitoring: Regular assessment for bleeding complications is essential 2
• Special situations:
  • If the patient requires oral anticoagulation, triple therapy significantly increases bleeding risk (2-3 fold) and should be avoided or minimized 2
  • For patients with prior stroke/TIA, prasugrel is contraindicated 5

Algorithm for DAPT Decision-Making After CABG

1. Determine clinical presentation:

   • Recent ACS → DAPT for 12 months (Class I)
   • Stable CAD → Consider DAPT for 12 months (Class IIb)

2. Assess bleeding risk:

   • High bleeding risk (age >75, low body weight, prior bleeding, oral anticoagulant use) → Consider aspirin monotherapy
   • Low/moderate bleeding risk → Proceed with recommended DAPT

3. Select P2Y12 inhibitor:

   • Clopidogrel is the preferred agent post-CABG
   • Avoid prasugrel in patients with history of stroke/TIA or age >75 years

4. Determine duration:

   • ACS patients: 12 months of DAPT
   • Stable CAD: Up to 12 months of DAPT may be reasonable
   • All patients: Lifelong aspirin therapy