When is dual antiplatelet therapy (DAPT) indicated?

When is Dual Antiplatelet Therapy Indicated?

Dual antiplatelet therapy (DAPT) is indicated for all patients with acute coronary syndrome (ACS) and for all patients undergoing percutaneous coronary intervention (PCI) with stent placement, regardless of clinical presentation. 1

Primary Indications for DAPT

Acute Coronary Syndrome

• DAPT is mandatory for all ACS patients (unstable angina, NSTEMI, or STEMI) regardless of whether they undergo PCI, medical management alone, or CABG 1
• The standard regimen consists of aspirin (75-100 mg daily) plus a P2Y12 inhibitor for 12 months 1, 2
• This applies to all ACS patients irrespective of the final revascularization strategy 1

Percutaneous Coronary Intervention with Stenting

• DAPT is required after all coronary stent placements (both drug-eluting stents and bare-metal stents) 1
• For stable ischemic heart disease (SIHD) patients undergoing PCI with drug-eluting stents: minimum 1 month of DAPT 1
• For SIHD patients with bare-metal stents: at least 1 month, with consideration for up to 6 months 1

P2Y12 Inhibitor Selection Algorithm

First-Line Agents for ACS

• Ticagrelor (180 mg loading dose, 90 mg twice daily) is the preferred first-line agent for all ACS patients, regardless of initial treatment strategy (invasive or conservative) 1, 2
• Prasugrel (60 mg loading dose, 10 mg daily; 5 mg daily if age ≥75 years or weight <60 kg) should be considered in preference to ticagrelor for NSTE-ACS patients who proceed to PCI 1, 2

Critical Contraindications

• Prasugrel is absolutely contraindicated in patients with prior stroke or transient ischemic attack due to increased cerebrovascular bleeding risk 3, 4
• Clopidogrel (300-600 mg loading dose, 75 mg daily) is reserved for patients who cannot tolerate or have contraindications to ticagrelor or prasugrel 1, 2

For Stable CAD/PCI

• Clopidogrel is the standard P2Y12 inhibitor for SIHD patients undergoing elective PCI 1

Duration of DAPT

Standard Duration

• ACS patients: 12 months of DAPT is the default duration regardless of revascularization strategy 1, 2
• SIHD patients after PCI: minimum 1 month for drug-eluting stents, with consideration for 1-3 months followed by P2Y12 inhibitor monotherapy 1

High Bleeding Risk Modifications

• Patients with high bleeding risk (PRECISE-DAPT score ≥25 or ARC-HBR criteria): consider 6 months of DAPT for ACS 1, 2
• For SIHD with high bleeding risk: 3 months of DAPT may be reasonable 1
• After shortened DAPT, transition to P2Y12 inhibitor monotherapy (discontinue aspirin, continue P2Y12 inhibitor) is reasonable 1, 5

Extended Duration

• For patients at high ischemic risk without increased bleeding risk: extended DAPT beyond 12 months may be considered 1, 6
• High ischemic risk includes: prior stent thrombosis, complex PCI, peripheral artery disease, diabetes with prior MI 1

Bleeding Risk Mitigation Strategies

Mandatory Measures

• Maintain aspirin dose at 75-100 mg daily (not higher doses) when used with DAPT 1, 2
• Prescribe a proton pump inhibitor (PPI) routinely with all DAPT regimens to reduce gastrointestinal bleeding 1, 2
• Use radial artery access (not femoral) for coronary angiography and PCI when performed by experienced operators 1, 2

Special Clinical Scenarios

Patients Requiring Oral Anticoagulation

• Triple therapy (DAPT + oral anticoagulant) should be limited to maximum 6 months or omitted after hospital discharge 1
• After initial period, transition to dual therapy (single antiplatelet agent + oral anticoagulant) 1
• Do not use ticagrelor or prasugrel as part of triple therapy; use clopidogrel only 1

Perioperative Management

• For elective non-cardiac surgery: delay surgery until at least 1 month after stent placement if both antiplatelet agents must be stopped 1
• Continue aspirin perioperatively whenever bleeding risk allows 2, 7
• Never discontinue DAPT within the first month after stent placement for elective surgery—the thrombotic risk is prohibitive 1, 8

Switching Between P2Y12 Inhibitors

• For ACS patients pre-treated with clopidogrel: switch to ticagrelor early after hospital admission (180 mg loading dose) regardless of clopidogrel timing or dose 2

Common Pitfalls to Avoid

• Do not use prasugrel in patients with prior stroke/TIA—this is an absolute contraindication with Class III: Harm designation 3, 4
• Do not withhold DAPT in ACS patients due to bleeding concerns—the thrombotic risk in the first 6-12 months typically outweighs bleeding risk 8, 4
• Do not use aspirin doses >100 mg daily with DAPT—higher doses increase bleeding without improving efficacy 1, 2
• Do not forget PPI prophylaxis—this is a Class I recommendation to reduce GI bleeding 1, 2
• Do not routinely pre-treat with P2Y12 inhibitors before coronary anatomy is known in patients planned for early invasive management—this increases bleeding without benefit 1