What are the antiplatelet therapy recommendations after Coronary Artery Bypass Grafting (CABG)?

Antiplatelet Therapy Recommendations After CABG

After coronary artery bypass grafting (CABG), all patients should receive aspirin 75-100 mg daily indefinitely, and those with recent acute coronary syndrome (ACS) should receive dual antiplatelet therapy (DAPT) with aspirin plus a P2Y12 inhibitor for 12 months. 1

Core Recommendations

For All CABG Patients:

• Aspirin therapy:
  • Should be initiated within 6 hours postoperatively if not started preoperatively 1
  • Recommended dose: 75-100 mg daily 1
  • Continue indefinitely 1

Based on Clinical Scenario:

1. Patients with Stable Ischemic Heart Disease (SIHD):

   • Aspirin monotherapy is the standard approach
   • DAPT with clopidogrel for 12 months may be reasonable to improve vein graft patency (Class IIb recommendation) 1

2. Patients with Recent ACS:

   • Resume P2Y12 inhibitor therapy postoperatively as soon as deemed safe 1
   • Complete 12 months of DAPT therapy after ACS (Class I recommendation) 1
   • Ticagrelor may be preferred over clopidogrel due to reduction in cardiovascular mortality 1

3. Patients with Recent PCI/Stent:

   • Resume P2Y12 inhibitor postoperatively 1
   • Continue DAPT until the recommended duration of therapy after PCI is completed 1

Evidence Analysis

Aspirin Monotherapy

Aspirin therapy after CABG has been consistently shown to:

• Improve vein graft patency, particularly during the first postoperative year 1
• Reduce major adverse cardiac events (MACE) 1
• Reduce mortality 2

Dual Antiplatelet Therapy

The evidence for DAPT after CABG shows:

• In ACS patients: DAPT for 12 months reduces ischemic events compared to aspirin alone 1
• In SIHD patients: DAPT may improve vein graft patency but increases bleeding risk 1, 3
• A recent meta-analysis found DAPT was associated with significantly lower all-cause mortality (OR 0.65) and cardiovascular mortality (OR 0.53) compared to single antiplatelet therapy, but higher rates of major bleeding (OR 1.30) 3

Choice of P2Y12 Inhibitor

• Ticagrelor compared to clopidogrel showed significant reduction in cardiovascular mortality in post-CABG patients in the PLATO study 1
• A recent meta-analysis found DAPT with ticagrelor/prasugrel was associated with lower all-cause mortality (OR 0.43) and cardiovascular mortality (OR 0.44) compared to DAPT with clopidogrel 3

Clinical Algorithm for Antiplatelet Therapy After CABG

1. Immediate post-operative period (within 6 hours):

   • Start or resume aspirin 75-100 mg daily

2. Early post-operative period (when hemostasis is assured):

   • For ACS patients: Resume P2Y12 inhibitor (preferably ticagrelor)
   • For patients with recent stent: Resume P2Y12 inhibitor based on stent type and timing

3. Duration of therapy:

   • All patients: Aspirin 75-100 mg daily indefinitely
   • ACS patients: P2Y12 inhibitor for 12 months
   • SIHD patients: Consider clopidogrel for 12 months to improve graft patency
   • Recent stent patients: Complete recommended DAPT duration based on stent type

Important Considerations and Pitfalls

• Bleeding risk: DAPT increases bleeding risk compared to aspirin alone 1, 3
• Timing of surgery after P2Y12 inhibitor: If possible, delay CABG after P2Y12 inhibitor discontinuation (5 days for clopidogrel, 3 days for ticagrelor, 7 days for prasugrel) 1, 4
• Restarting P2Y12 inhibitors: Only when hemostasis is assured to prevent bleeding complications 5
• Off-pump CABG: May derive greater benefit from DAPT compared to on-pump CABG 6, 7
• Dose of aspirin: Lower doses (75-100 mg) are preferred to minimize bleeding while maintaining efficacy 1

By following these evidence-based recommendations, clinicians can optimize antiplatelet therapy after CABG to reduce mortality and improve graft patency while minimizing bleeding complications.