Indications for Single Antiplatelet Therapy (SAPT)
Single antiplatelet therapy is recommended for established coronary artery disease, symptomatic peripheral arterial disease, and after the first year post-acute coronary syndrome or stent placement to reduce the risk of major adverse cardiovascular events. 1
Primary Prevention
- In persons aged 50 years or older without symptomatic cardiovascular disease, low-dose aspirin 75-100 mg daily may be considered for primary prevention (Grade 2B) 1
- The benefit is most pronounced when taken over 10 years, with a slight reduction in total mortality regardless of cardiovascular risk profile 1
- The decision should consider the balance between MI reduction and increased bleeding risk, particularly in moderate to high-risk cardiovascular patients 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 (Grade 1A) 1
- This includes patients 1-year post-acute coronary syndrome, with prior revascularization, coronary stenoses >50% by angiogram, and/or evidence of cardiac ischemia on diagnostic testing 1
- SAPT is preferred over dual antiplatelet therapy in these patients (Grade 2B) 1
Post-Acute Coronary Syndrome and Stent Placement
- After the first year of an acute coronary syndrome, SAPT is recommended over continued dual antiplatelet therapy (Grade 1B) 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 (minimum) of dual antiplatelet therapy 1
- After 12 months of dual antiplatelet therapy for any stent type, SAPT is recommended (Grade 1B) 1
Peripheral Arterial Disease (PAD)
- In patients with symptomatic PAD, SAPT is recommended to reduce the risk of major adverse cardiovascular events (MACE) (Grade 1A) 1
- Options include:
- In patients with asymptomatic PAD, SAPT is reasonable to reduce MACE risk (Grade 2a, C-EO) 1
- After endovascular or surgical revascularization for PAD, antiplatelet therapy is recommended (Grade 1B-R) 1
Cerebrovascular Disease
- For long-term secondary prevention in patients with non-cardioembolic ischemic stroke or TIA who do not require anticoagulation, SAPT is indicated 1, 2, 3
- Options include aspirin 81-325 mg daily, clopidogrel 75 mg daily, or aspirin + dipyridamole 25/200 mg daily 1, 2
- After the initial 21-30 day period of dual antiplatelet therapy for minor stroke or high-risk TIA, patients should transition to long-term SAPT 1, 4, 2
Special Considerations
- 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, SAPT is recommended 1
- In patients with atrial fibrillation and stable coronary artery disease (>1 year post-event), oral anticoagulation monotherapy is preferred over combination with antiplatelet therapy 5
- SAPT with clopidogrel has shown improved efficacy compared to aspirin for MACE prevention in PAD patients, with similar bleeding rates 1
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, 6
- Using full-intensity oral anticoagulation in PAD patients without another indication (e.g., atrial fibrillation) should be avoided as it increases bleeding risk without benefit (Grade 3: Harm, A) 1
- Underdosing antiplatelet medications reduces efficacy without decreasing bleeding risk 5
- Overlooking drug interactions that may reduce antiplatelet efficacy, particularly with clopidogrel and CYP2C19 inhibitors 7, 8
By following these evidence-based recommendations for SAPT, clinicians can effectively reduce cardiovascular risk while minimizing bleeding complications in appropriate patient populations.