When to use dual antiplatelet therapy (DAPT) versus single antiplatelet therapy (SAPT) in patients with coronary artery disease (CAD) and what is the recommended duration of therapy?

Dual and Single Antiplatelet Therapy in CAD: When and How Long

For acute coronary syndrome (ACS), use dual antiplatelet therapy (DAPT) with aspirin plus ticagrelor or prasugrel for 12 months; for stable CAD with PCI, use DAPT with aspirin plus clopidogrel for 1-6 months depending on bleeding risk, then transition to aspirin monotherapy indefinitely. 1

Clinical Decision Algorithm

ACS Patients (STEMI, NSTEMI, Unstable Angina)

P2Y12 Inhibitor Selection:

• First-line: Ticagrelor (180 mg loading, 90 mg twice daily) plus aspirin (75-100 mg daily) 1, 2, 3
• Alternative for PCI patients: Prasugrel (60 mg loading, 10 mg daily) plus aspirin, specifically for P2Y12-naïve patients proceeding to PCI 2, 4
• Use clopidogrel (600 mg loading, 75 mg daily) ONLY when: 1
  • Prior stroke/TIA (prasugrel is contraindicated) 4
  • Concomitant oral anticoagulation required 1
  • Ticagrelor or prasugrel contraindicated or unavailable 1

Duration:

• Standard: 12 months for all ACS patients regardless of revascularization strategy (medical therapy, PCI, or CABG) 1, 3
• Shortened to 6 months: High bleeding risk patients (PRECISE-DAPT score ≥25) 1, 5
• Extended beyond 12 months: May be considered in patients who tolerated DAPT without bleeding complications and remain at high ischemic risk 1

Stable CAD with PCI

P2Y12 Inhibitor Selection:

• Default: Clopidogrel (600 mg loading, 75 mg daily) plus aspirin 1

Duration:

• Standard: 1-6 months depending on bleeding risk, irrespective of stent type (BMS or DES) 1
• High bleeding risk (PRECISE-DAPT ≥25): 3 months 1
• Very high bleeding risk: 1 month may be considered 1
• Low bleeding risk with high ischemic risk: Longer duration may be considered 1

Stable CAD with CABG

Insufficient data to recommend DAPT in this population 1

After DAPT Completion: Lifelong Single Antiplatelet Therapy

Aspirin monotherapy (75-100 mg daily) indefinitely after completing DAPT course 1

Critical Bleeding Risk Mitigation Strategies

Every patient on DAPT requires these interventions to reduce mortality and morbidity from bleeding:

• Radial artery access over femoral for PCI when performed by experienced operator 1, 5
• Low-dose aspirin: 75-100 mg daily (not higher doses) 1, 5
• Proton pump inhibitor (PPI): Mandatory for all patients on DAPT to reduce GI bleeding 1, 3, 5
• Avoid omeprazole/esomeprazole with clopidogrel due to CYP2C19 interaction; use pantoprazole or rabeprazole instead 5, 6

Special Clinical Scenarios

Triple Therapy (DAPT + Oral Anticoagulation)

• Duration: Maximum 6 months, or discontinue after hospital discharge based on ischemic vs bleeding risk 1
• P2Y12 inhibitor: Use clopidogrel (NOT ticagrelor or prasugrel) 1, 5
• Bleeding risk: 2-3 fold increase compared to anticoagulation alone 1

Perioperative Management

• Minimum DAPT duration before elective surgery: 1 month, regardless of stent type, if aspirin can be continued 1
• Continue aspirin perioperatively if bleeding risk allows 1, 3
• Resume DAPT as soon as possible postoperatively 3, 5

High-Risk Populations Requiring Prolonged DAPT

Consider extended DAPT beyond 12 months in: 1

• Prior stent thrombosis without correctable cause
• Peripheral artery disease
• Complex PCI (≥3 stents, ≥3 lesions, bifurcation with 2 stents, total stent length >60 mm, chronic total occlusion)

Dose Adjustments

Prasugrel: 4

• Age ≥75 years: Generally not recommended (increased fatal/intracranial bleeding risk)
• Weight <60 kg: Consider 5 mg daily maintenance dose (instead of 10 mg)
• Prior stroke/TIA: Contraindicated

Clopidogrel: 6

• CYP2C19 poor metabolizers: Consider alternative P2Y12 inhibitor (ticagrelor or prasugrel) due to reduced efficacy

Critical Pitfalls to Avoid

• Never use clopidogrel as first-line in ACS when ticagrelor or prasugrel are available and not contraindicated 2, 3
• Never discontinue DAPT within first month after stent placement for elective surgery—dramatically increases stent thrombosis, MI, and death risk 1, 3
• Never fail to prescribe PPI with DAPT—this simple intervention significantly reduces GI bleeding 1, 3, 5
• Never give prasugrel to patients with prior stroke/TIA—contraindicated due to increased cerebrovascular events (6.5% vs 1.2% with clopidogrel) 4
• Never assume stent type dictates DAPT duration—base decision on ischemic vs bleeding risk assessment, not whether BMS or DES was used 1

Nuances in the Evidence

The 2017 ESC guidelines 1 and 2016 ACC/AHA guidelines 1 align on core principles but differ slightly in emphasis. The ESC guidelines provide more granular bleeding risk stratification and explicitly state that stent type should not determine DAPT duration 1. The ACC/AHA guidelines emphasize that for stable CAD without prior ACS, DAPT beyond standard duration provides no benefit 1. Recent research 7, 8, 9 supports shorter DAPT durations (3-6 months) in high bleeding risk patients without compromising ischemic outcomes, validating the guideline recommendations for individualized duration based on bleeding risk assessment.