What are the indications for dual antiplatelet (DAPT) treatment in patients with acute coronary syndrome (ACS) or those who have undergone percutaneous coronary intervention (PCI) with stent placement?

Indications for Dual Antiplatelet Therapy

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. 1, 2

Primary Indications

Acute Coronary Syndrome

• DAPT is mandatory for all ACS patients regardless of management strategy, including those managed with PCI, medical therapy alone, or coronary artery bypass grafting (CABG). 2, 3
• This includes patients with:
  • ST-elevation myocardial infarction (STEMI) - whether managed with primary PCI, delayed PCI, or fibrinolytic therapy 1, 4
  • Non-ST-elevation myocardial infarction (NSTEMI) 1, 4
  • Unstable angina 4

Percutaneous Coronary Intervention with Stent Placement

• DAPT is essential for all patients undergoing PCI with stent placement to prevent stent thrombosis, regardless of whether the indication is ACS or stable coronary artery disease. 2
• This applies to both bare-metal stents (BMS) and drug-eluting stents (DES). 1

Optimal DAPT Regimen

First-Line Therapy

• Aspirin 75-100 mg daily PLUS ticagrelor (180 mg loading dose, then 90 mg twice daily) is the first-line regimen for ACS patients. 2, 3
• Prasugrel (60 mg loading dose, then 10 mg daily) plus aspirin is an alternative for P2Y12 inhibitor-naïve patients with NSTE-ACS or STEMI undergoing PCI, unless high bleeding risk or contraindications exist. 2
• Ticagrelor or prasugrel are strongly preferred over clopidogrel for ACS patients. 2, 3

When to Use Clopidogrel Instead

• Clopidogrel (600 mg loading dose, then 75 mg daily) plus aspirin should be used when ticagrelor or prasugrel are contraindicated, specifically for patients with:
  • Prior intracranial bleeding 2
  • Indication for oral anticoagulation 2
  • High bleeding risk with inability to tolerate more potent P2Y12 inhibition 2

Critical Contraindication

• Prasugrel should NOT be administered to patients with prior stroke or transient ischemic attack (TIA) - this is a Class III: Harm recommendation. 1, 2

Standard Duration of DAPT

ACS Patients

• The default DAPT duration is 12 months for all ACS patients who are not at high bleeding risk, regardless of ACS type, stent type, or completeness of revascularization. 1, 2, 3
• For ACS patients treated with fibrinolytic therapy, P2Y12 inhibitor therapy (clopidogrel) should be continued for a minimum of 14 days and ideally at least 12 months. 1

High Bleeding Risk Patients

• In ACS patients with high bleeding risk (e.g., PRECISE-DAPT score ≥25), a shortened DAPT duration of 6 months may be reasonable. 1, 2
• However, the SMART-DATE trial showed increased myocardial infarction risk with 6-month DAPT compared to 12-month DAPT in ACS patients, suggesting caution with shortened duration. 5

Extended DAPT Beyond 12 Months

• 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

Bleeding Risk Mitigation Strategies

Essential Co-Interventions

• Prescribe a proton pump inhibitor (PPI) with DAPT in all patients to reduce gastrointestinal bleeding risk - this is a Class I recommendation. 2, 3, 6
• Use radial artery access over femoral access for PCI when performed by an experienced radial operator. 2, 3
• Maintain aspirin dose at 75-100 mg daily (not higher doses) when combined with a P2Y12 inhibitor. 1, 2

Special Clinical Scenarios

Post-CABG Patients

• In ACS patients treated with DAPT who undergo CABG, P2Y12 inhibitor therapy should be resumed after CABG to complete 12 months of DAPT therapy. 1

Perioperative Management

• Continue aspirin perioperatively if bleeding risk allows. 2
• Do not discontinue DAPT within the first month after stent placement for elective non-cardiac surgery - the thrombotic risk is highest in the first month after ACS. 2, 6
• Resume antiplatelet therapy as soon as possible post-operatively. 2

Patients Requiring Anticoagulation

• For patients requiring long-term anticoagulation, discontinue aspirin 1-4 weeks after PCI and continue P2Y12 inhibitor (preferably clopidogrel rather than ticagrelor). 2, 3

Critical Pitfalls to Avoid

• Never discontinue DAPT prematurely, especially within the first month after stent placement - this dramatically increases risk of stent thrombosis, myocardial infarction, and death. 2, 3, 6
• Never fail to prescribe a PPI with DAPT - this simple intervention significantly reduces gastrointestinal bleeding. 2, 3
• Never use clopidogrel as first-line therapy when ticagrelor or prasugrel are available and not contraindicated - this represents suboptimal care for ACS patients. 2, 3
• Never administer prasugrel to patients with prior stroke or TIA - this is contraindicated due to increased cerebrovascular bleeding risk. 1, 2