What is the recommended duration of dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor, such as clopidogrel (Plavix) or ticagrelor (Brilinta), after Coronary Artery Bypass Grafting (CABG)?

Duration of Dual Antiplatelet Therapy After CABG

In patients with acute coronary syndrome (ACS) who undergo coronary artery bypass grafting (CABG), P2Y12 inhibitor therapy should be resumed after CABG to complete a total of 12 months of dual antiplatelet therapy (DAPT) after the ACS event. 1

Recommendations Based on Clinical Scenario

For ACS Patients Undergoing CABG:

• P2Y12 inhibitor therapy should be resumed post-CABG to complete 12 months of DAPT following the initial ACS event 1
• Daily low-dose aspirin (75-100 mg) should be continued indefinitely 1
• Ticagrelor is preferred over clopidogrel for maintenance P2Y12 inhibitor therapy in ACS patients after stent implantation 1
• For patients who cannot receive ticagrelor, clopidogrel is the recommended alternative 1

For Stable Ischemic Heart Disease (SIHD) Patients Undergoing CABG:

• DAPT with clopidogrel initiated early post-operatively for 12 months after CABG may be reasonable to improve vein graft patency 1
• This recommendation is less strong (Class IIb) than for ACS patients 1

Special Considerations

Bleeding Risk Assessment:

• In ACS patients who develop high bleeding risk after CABG (e.g., requiring oral anticoagulation therapy) or experience significant bleeding, discontinuation of P2Y12 therapy after 6 months may be reasonable 1
• Prasugrel should not be administered to patients with prior history of stroke or TIA 1

Extended DAPT Therapy:

• In ACS patients who have tolerated DAPT without bleeding complications and are not at high bleeding risk, continuation beyond 12 months may be reasonable 1
• The optimal duration of prolonged DAPT beyond 1 year is not well established 2

Emerging Evidence

Recent research suggests potential alternative approaches that are still being investigated:

• Short-term DAPT (1 month) with ticagrelor plus aspirin after CABG in stable coronary syndrome patients is being evaluated in the ODIN trial 3
• Adding ticagrelor to aspirin for 1 year after CABG has shown reduction in vein graft failure but with increased bleeding risk 4

Common Pitfalls to Avoid

• Failure to resume P2Y12 inhibitor after CABG: Many clinicians incorrectly discontinue P2Y12 inhibitors after CABG in ACS patients, but guidelines clearly recommend resuming therapy to complete the 12-month course 1
• Inappropriate P2Y12 inhibitor selection: Prasugrel should be avoided in patients with history of stroke/TIA or those >75 years or <60 kg 2
• Suboptimal aspirin dosing: Using higher than recommended aspirin doses (>100 mg daily) increases bleeding risk without additional benefit 1

Algorithm for DAPT Management After CABG

1. Determine patient's initial presentation:

   • ACS within past year: Complete 12 months of DAPT from time of ACS event 1
   • Stable CAD: Consider DAPT for 12 months to improve graft patency (Class IIb recommendation) 1

2. Assess bleeding risk:

   • Low bleeding risk: Complete recommended DAPT duration 1
   • High bleeding risk: Consider shorter DAPT duration (minimum 6 months for ACS patients) 1, 2

3. Select appropriate P2Y12 inhibitor:

   • First choice for ACS: Ticagrelor (90 mg twice daily) 1
   • Alternative: Clopidogrel (75 mg daily) 1
   • Avoid prasugrel in patients with history of stroke/TIA 1

4. Continue low-dose aspirin indefinitely (75-100 mg daily) after completing DAPT course 1