When is extended dual antiplatelet therapy (DAPT) with medications such as aspirin and a P2Y12 inhibitor (e.g. clopidogrel) indicated after percutaneous coronary intervention (PCI)?

Extended Dual Antiplatelet Therapy After PCI: Indications and Scenarios

Extended dual antiplatelet therapy (DAPT) beyond the standard duration should be considered in patients with high ischemic risk and low bleeding risk, particularly those with acute coronary syndrome (ACS) who have tolerated initial DAPT without bleeding complications. 1

Standard DAPT Duration Guidelines

The current guidelines recommend the following standard DAPT durations after PCI:

• Stable Ischemic Heart Disease (SIHD) with DES: At least 1-3 months of DAPT, with consideration for up to 12 months 1
• Acute Coronary Syndrome (ACS): At least 12 months of DAPT 1, 2

Scenarios for Extended DAPT (>12 months)

High Ischemic Risk/Low Bleeding Risk Patients

Extended DAPT beyond 12 months may be reasonable (Class IIb) in patients with:

• History of previous myocardial infarction 2
• Complex PCI procedures (multiple stents, long stents, bifurcation stenting) 1, 2
• Diabetes mellitus with diffuse coronary disease 1, 2
• Multivessel coronary artery disease 2, 3
• History of recurrent myocardial infarctions 2
• Previous stent thrombosis while on appropriate antiplatelet therapy 1

Evidence Supporting Extended DAPT

The most recent evidence shows that extended DAPT:

• Reduces ischemic events, particularly myocardial infarction 4
• May provide mortality benefit in carefully selected high-risk patients 3
• Provides greater benefit in ACS patients compared to stable coronary disease 1, 4

When to Avoid Extended DAPT

Extended DAPT should be avoided in patients with:

• High bleeding risk factors:
  • Advanced age (≥75 years) 5
  • Low body weight (<60 kg) 5
  • History of bleeding complications 2, 6
  • Need for oral anticoagulation 1, 2
  • Chronic kidney disease 2
  • Concurrent use of medications that increase bleeding risk 5

Transitioning Strategies

Recent guidelines suggest alternative approaches to extended antithrombotic therapy:

1. P2Y12 Inhibitor Monotherapy: In selected patients, discontinuation of aspirin after 1-3 months with continued P2Y12 inhibitor monotherapy is reasonable (Class IIa) to reduce bleeding while maintaining ischemic protection 1, 7

2. Short DAPT followed by monotherapy: For high bleeding risk patients, shorter DAPT (1-3 months) followed by P2Y12 inhibitor monotherapy has shown reduced bleeding without increased ischemic events 7, 6, 8

Choice of P2Y12 Inhibitor for Extended Therapy

• Clopidogrel: Standard choice for stable coronary disease patients 2
• Ticagrelor or Prasugrel: Preferred for ACS patients if no contraindications exist 2
  • Prasugrel is contraindicated in patients with prior stroke/TIA 5

Common Pitfalls to Avoid

1. Premature DAPT discontinuation: This increases risk of stent thrombosis, myocardial infarction, and death, especially within the first months after PCI 5

2. Extending DAPT without considering bleeding risk: Always assess bleeding risk using validated scores before extending DAPT 1, 6

3. Inadequate gastroprotection: Proton pump inhibitors should be considered for the duration of DAPT, especially in patients with risk factors for gastrointestinal bleeding 2

4. Failure to reassess risk-benefit ratio: The decision for extended DAPT should be reevaluated periodically, especially if new bleeding risk factors develop

Decision Algorithm for Extended DAPT

1. Assess baseline ischemic and bleeding risks
2. For patients with ACS: Consider extended DAPT beyond 12 months if:
   • No significant bleeding on initial DAPT
   • High ischemic risk features present
   • No high bleeding risk features
3. For patients with stable CAD: Standard DAPT duration is sufficient in most cases; extended DAPT only in very high ischemic risk cases
4. For patients with both high ischemic and bleeding risks: Consider alternative strategies like P2Y12 inhibitor monotherapy after 1-3 months of DAPT

Extended DAPT remains an individualized decision, but the evidence clearly supports its use in specific high ischemic risk scenarios where the benefit of preventing recurrent events outweighs the increased bleeding risk.