What are the indications for single antiplatelet therapy (APT)?

Indications for Single Antiplatelet Therapy (SAPT)

Single antiplatelet therapy is indicated for primary prevention in high-risk individuals, established coronary artery disease, after a period of dual antiplatelet therapy following acute coronary syndrome or stent placement, peripheral arterial disease, and non-cardioembolic cerebrovascular disease. 1

Primary Prevention

• SAPT with low-dose aspirin (75-100 mg daily) is recommended for primary prevention in persons aged 50 years or older without symptomatic cardiovascular disease 1
• The benefit is most pronounced when taken over 10 years, with a slight reduction in total mortality regardless of cardiovascular risk profile 1

Established Coronary Artery Disease

• Long-term SAPT with aspirin 75-100 mg daily or clopidogrel 75 mg daily is recommended for patients with established coronary artery disease 1
• SAPT is preferred over dual antiplatelet therapy in patients with stable coronary artery disease 1
• For patients with stable coronary artery disease, oral anticoagulation monotherapy is preferred over combination therapy with aspirin in those who also have atrial fibrillation 2

Post-Acute Coronary Syndrome and Stent Placement

• SAPT is recommended over continued dual antiplatelet therapy after the first year of an acute coronary syndrome 1
• For patients with bare-metal stents, SAPT is recommended after the first month of dual antiplatelet therapy 1
• For patients with drug-eluting stents, SAPT is recommended after 3-6 months of dual antiplatelet therapy 1
• Prolonged dual antiplatelet therapy beyond 12 months increases bleeding risk without providing additional benefit in most patients 3

Peripheral Arterial Disease (PAD)

• SAPT is indicated to reduce the risk of major adverse cardiovascular events in patients with symptomatic PAD 1
• Options include:
  • Clopidogrel 75 mg daily (preferred option) 1
  • Aspirin 75-325 mg daily 1
• Clopidogrel has shown improved efficacy compared to aspirin for MACE prevention in PAD patients, with similar bleeding rates 1

Cerebrovascular Disease

• SAPT is indicated for long-term secondary prevention in patients with non-cardioembolic ischemic stroke or TIA who do not require anticoagulation 1, 4
• Options for SAPT in cerebrovascular disease include:
  • Aspirin 81-325 mg daily 1
  • Clopidogrel 75 mg daily 1
  • Aspirin + dipyridamole 25/200 mg daily 1
• Short-term dual antiplatelet therapy (21-30 days) followed by SAPT is more effective than immediate SAPT in patients with minor acute non-cardioembolic stroke or high-risk TIA 4

Special Considerations

• SAPT with clopidogrel is recommended for patients with anterior MI and LV thrombus who do not undergo stenting, after 3 months of warfarin plus aspirin, and subsequent dual antiplatelet therapy for up to 12 months 1
• When selecting an antiplatelet agent, consider CYP2C19 polymorphisms, as diminished antiplatelet effect may occur in patients with loss-of-function alleles of the CYP2C19 gene when using clopidogrel 5, 4
• For patients with atrial fibrillation and stable coronary artery disease, oral anticoagulation monotherapy is preferred over combination therapy with antiplatelet agents 2

Common Pitfalls to Avoid

• Continuing dual antiplatelet therapy beyond 12 months after ACS or stent placement without specific indications increases bleeding risk without additional benefit 1, 3
• Using full-intensity oral anticoagulation in PAD patients without another indication should be avoided as it increases bleeding risk without benefit 1
• Adding antiplatelet therapy to oral anticoagulation without a clear indication significantly increases bleeding risk without additional benefit for stroke prevention 2
• Underdosing direct oral anticoagulants should be avoided unless specific criteria for dose reduction are met 2