What is the recommended antiplatelet (Dual Antiplatelet Therapy, DAPT) regimen for a patient with a bare metal stent?

Antiplatelet Regimen for Bare Metal Stent

For patients with bare metal stents (BMS), dual antiplatelet therapy (DAPT) with aspirin and clopidogrel should be administered for a minimum of 1 month, with continuation for up to 12 months if the patient is not at high risk for bleeding. 1

Initial Regimen and Duration

• First month (mandatory):

  • Aspirin 75-325 mg daily AND
  • Clopidogrel 75 mg daily 1

• Months 2-12 (recommended):

  • Low-dose aspirin 75-100 mg daily AND
  • Clopidogrel 75 mg daily 1

• Beyond 12 months:

  • Single antiplatelet therapy with low-dose aspirin 75-100 mg daily indefinitely 1

Evidence-Based Rationale

The risk of stent thrombosis with BMS is highest in the first days to weeks after implantation 1. The 2016 ACC/AHA guidelines clearly state that the minimum duration of DAPT for BMS is 1 month, as this is the critical period for stent endothelialization 1. This recommendation is based on the understanding that BMS generally require less time for complete endothelialization compared to drug-eluting stents.

For patients who received a BMS in the setting of an acute coronary syndrome (ACS), DAPT should be continued for at least 12 months regardless of stent type 1. This longer duration is supported by evidence showing reduced ischemic events in this high-risk population.

Special Considerations

Patients with High Bleeding Risk

• If bleeding risk is high, the minimum 1-month DAPT duration should still be maintained
• BMS are often specifically chosen for patients who cannot receive DAPT for more than approximately 1 month due to:
  • Active bleeding concerns
  • Anticipated non-cardiac surgery
  • Known medication non-adherence issues 1

Patients Requiring Anticoagulation

For patients with BMS who also require oral anticoagulation (e.g., for atrial fibrillation):

• Triple therapy (warfarin, aspirin, clopidogrel) for 1 month
• Then warfarin plus single antiplatelet therapy for months 2-3
• After 3 months, discontinue clopidogrel and continue warfarin plus low-dose aspirin 1

Choice of P2Y12 Inhibitor

• Clopidogrel is the P2Y12 inhibitor of choice for BMS in stable coronary artery disease 1
• For ACS patients with BMS, ticagrelor is reasonable to prefer over clopidogrel 1
• Prasugrel may be considered over clopidogrel in ACS patients without history of stroke/TIA 1

Common Pitfalls to Avoid

1. Premature discontinuation: Stopping DAPT before completing the minimum 1-month period significantly increases the risk of catastrophic stent thrombosis, which carries a 20-45% mortality rate 1

2. Inappropriate aspirin dosing: While higher aspirin doses (162-325 mg) are recommended initially, low-dose aspirin (75-100 mg) is recommended for long-term therapy to reduce bleeding risk 1, 2

3. Failure to restart therapy after temporary interruption: If DAPT must be interrupted for surgery within the first month, restart as soon as possible, ideally within 24-48 hours 3

4. Not considering gastroprotection: Proton pump inhibitors should be used in patients with history of gastrointestinal bleeding and are reasonable in those with increased risk of GI bleeding 1

By following these evidence-based recommendations for antiplatelet therapy after BMS placement, clinicians can effectively balance the prevention of stent thrombosis against bleeding risks, ultimately improving patient outcomes in terms of mortality, morbidity, and quality of life.