When to give dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor?

When to Give Dual Antiplatelet Therapy (DAPT)

DAPT with aspirin plus a P2Y12 inhibitor should be initiated immediately in all patients with acute coronary syndrome (ACS) and continued for at least 12 months, regardless of whether they undergo percutaneous coronary intervention (PCI), medical management alone, or fibrinolytic therapy. 1, 2

Acute Coronary Syndrome (Primary Indication)

Immediate Initiation

• Start DAPT as soon as ACS is diagnosed, with aspirin loading dose (162-325 mg) followed by maintenance (75-100 mg daily) plus a P2Y12 inhibitor loading dose 1, 2
• This applies to all ACS presentations: STEMI, NSTE-ACS, and unstable angina 1

P2Y12 Inhibitor Selection in ACS

First-line choice: Ticagrelor (180 mg loading, 90 mg twice daily) over clopidogrel for superior outcomes 1, 2

Alternative: Prasugrel (60 mg loading, 10 mg daily) for P2Y12-naïve patients undergoing PCI, unless:

• Prior stroke/TIA (absolute contraindication) 2, 3, 4
• Age >75 years or weight <60 kg 4

Use clopidogrel (600 mg loading, 75 mg daily) only when:

• Prior intracranial hemorrhage 2
• Concurrent oral anticoagulation needed 2
• High bleeding risk with inability to tolerate potent P2Y12 inhibition 2

Duration in ACS

• Standard: 12 months minimum for all ACS patients (with or without PCI) 1, 2
• Consider shortening to 6 months if PRECISE-DAPT score ≥25 or high bleeding risk develops 1, 2
• May extend beyond 12 months if tolerated without bleeding and not at high bleeding risk 1

After Percutaneous Coronary Intervention

For ACS + PCI

• Minimum 12 months DAPT regardless of stent type (bare metal or drug-eluting) 1
• Ticagrelor or prasugrel preferred over clopidogrel 1, 2

For Stable Ischemic Heart Disease + PCI

• Drug-eluting stent: 6 months DAPT (Class I) 1
• Bare metal stent: 1 month DAPT minimum 1
• High bleeding risk patients: Consider 3 months for DES or 1 month for BMS 1

After Coronary Artery Bypass Grafting (CABG)

• Resume DAPT as soon as possible postoperatively in patients with recent ACS or stent implantation 1
• Complete the recommended 12-month period from the index ACS event 1
• For stable CAD post-CABG, 12-month DAPT may be considered to improve vein graft patency 1

Peripheral Artery Disease (PAD)

After Lower Extremity Revascularization

• DAPT for 1-6 months after endovascular revascularization is reasonable 1
• Consider DAPT for ≥1 month after surgical revascularization with prosthetic graft 1
• Transition to single antiplatelet therapy (aspirin or clopidogrel alone) for long-term maintenance 1

Alternative: Rivaroxaban + Aspirin

• Low-dose rivaroxaban (2.5 mg twice daily) plus aspirin is effective for reducing MACE and major adverse limb events after PAD revascularization 1

Stroke/TIA (Limited Role)

• DAPT for 21-30 days in very high-risk TIA or minor ischemic stroke reduces recurrence 5, 6
• Do not extend beyond 21-30 days due to increased bleeding risk without additional benefit 7, 6
• This is not the same indication as ACS—duration is much shorter 7

Key Bleeding Risk Mitigation Strategies

• Use radial access for coronary procedures when performed by expert operator 2
• Prescribe proton pump inhibitor with all DAPT regimens 2
• Maintain aspirin dose at 75-100 mg daily (not higher doses) 1, 2
• When using ticagrelor, aspirin must be ≤100 mg daily 1

Critical Pitfalls to Avoid

• Never discontinue DAPT within first month after stent placement for elective non-cardiac surgery 2
• Do not give prasugrel to patients with prior stroke/TIA—this is contraindicated due to increased cerebrovascular events 2, 3, 4
• Do not use higher aspirin doses (>100 mg) with ticagrelor—this reduces efficacy 1
• Do not confuse stroke/TIA DAPT duration (21-30 days) with ACS duration (12 months)—these are completely different indications 7, 6
• Minor bleeding like conjunctival hemorrhage is not an indication to stop DAPT—thrombotic risk outweighs minor bleeding risk 5