Is dual antiplatelet therapy (DAPT) required after Coronary Artery Bypass Grafting (CABG)?

Dual Antiplatelet Therapy After CABG

DAPT is NOT routinely required after CABG in stable coronary artery disease patients, but IS required for 12 months in patients who underwent CABG following an acute coronary syndrome. 1, 2

Standard Post-CABG Antiplatelet Therapy

All CABG patients should receive aspirin monotherapy (75-100 mg daily) started within 6-24 hours postoperatively and continued indefinitely. 2, 3 This is the cornerstone of post-CABG antiplatelet therapy, as aspirin significantly improves saphenous vein graft patency and reduces mortality, myocardial infarction, stroke, renal failure, and bowel infarction. 2

• Aspirin should be initiated as soon as hemostasis is secured, ideally within 6-24 hours after surgery. 3
• Delaying aspirin beyond 48 hours eliminates the graft patency benefit. 2

When DAPT IS Required After CABG

Post-ACS Patients (12-Month DAPT Mandatory)

Patients who undergo CABG following an acute coronary syndrome (unstable angina, NSTEMI, or STEMI) MUST resume P2Y12 inhibitor therapy postoperatively to complete 12 months of DAPT from the time of the ACS event. 1, 3, 4 This applies regardless of whether they received prior stent implantation or were managed with medical therapy alone. 4

• Resume the P2Y12 inhibitor as soon as bleeding is adequately controlled, typically within 24-48 hours after surgery when chest tube drainage is no longer significant. 4
• Ticagrelor or prasugrel are preferred over clopidogrel for maintenance therapy in post-ACS patients after CABG, provided there are no contraindications. 4
• Prasugrel should NOT be used in patients with prior stroke or TIA due to increased risk of intracranial hemorrhage. 4
• Recent meta-analysis shows ticagrelor plus aspirin reduces all-cause mortality (OR 0.47) and cardiovascular mortality (OR 0.50) compared to clopidogrel plus aspirin, with no increase in major bleeding. 5

Patients with Prior Coronary Stenting

Patients with prior coronary stents should resume P2Y12 inhibitor postoperatively to complete the recommended duration of DAPT for the stent type (minimum 1 month for bare metal stents, at least 6 months for drug-eluting stents). 3

High Bleeding Risk Modification

In CABG patients with prior MI who are at high risk of severe bleeding, discontinuation of P2Y12 inhibitor therapy after 6 months (instead of 12 months) should be considered. 4

When DAPT Is NOT Routinely Required

Stable Coronary Artery Disease (Chronic Coronary Syndromes)

The European Society of Cardiology explicitly states that DAPT is NOT routinely indicated after CABG for chronic coronary syndromes. 1, 2 There is insufficient data to recommend DAPT in this patient population. 1

• DAPT may be considered in selected cases at increased risk of graft occlusion who are NOT at high bleeding risk, but this is not standard practice. 2
• If DAPT is used in stable CAD, clopidogrel 75 mg daily should be added to aspirin for 6-12 months, though optimal duration remains uncertain. 2
• Meta-analysis shows DAPT reduces early saphenous vein graft occlusion (RR 0.59) but may increase major bleeding risk (RR 1.17). 6

Evidence Nuances and Considerations

Off-Pump CABG Benefit

Pooled analysis shows DAPT appears most beneficial in off-pump CABG patients, reducing perioperative MI by 68% and saphenous graft occlusion by 55% compared to aspirin alone. 6 However, this benefit is less clear in on-pump CABG. 6

Bleeding Risk Management

A proton pump inhibitor should be added in patients at increased GI bleeding risk (elderly, history of GI bleeding, chronic NSAID users) to reduce gastrointestinal bleeding with antithrombotic therapy. 2, 3

Extended DAPT Beyond 12 Months

In patients perceived to be at high ischemic risk with prior MI and CABG who have tolerated DAPT without bleeding complications, continuation of DAPT for longer than 12 months and up to 36 months may be considered. 4

Aspirin Alternative

If aspirin is contraindicated or not tolerated, clopidogrel 75 mg daily is a reasonable alternative. 2

Key Clinical Pitfalls to Avoid

• Do NOT routinely prescribe DAPT in stable CCS patients after CABG—the bleeding risk outweighs benefits in most cases. 2
• Do NOT delay aspirin initiation beyond 48 hours, as this eliminates the graft patency benefit. 2
• Do NOT forget to resume P2Y12 inhibitor therapy in post-ACS patients—this is mandatory for 12 months. 3, 4
• Do NOT use prasugrel in patients with prior stroke/TIA. 4