What is the recommended treatment with aspirin (acetylsalicylic acid) for a patient with significant artery blockage and no history of bleeding or aspirin allergy?

Aspirin Treatment for Artery Blockage

For patients with significant artery blockage (atherosclerotic vascular disease), aspirin 75-162 mg daily should be initiated immediately and continued lifelong unless contraindicated. 1, 2

Recommended Aspirin Dosing

• Start aspirin 75-162 mg daily immediately for all patients with documented coronary artery disease, peripheral arterial disease, or cerebrovascular atherosclerosis 1, 2
• The most recent high-quality evidence supports 75-100 mg daily as the optimal long-term dose, balancing efficacy with bleeding risk 1
• Doses between 75-325 mg appear equally effective for secondary prevention, but lower doses (75-100 mg) minimize gastrointestinal bleeding complications 1, 3

Alternative Antiplatelet Therapy

If true aspirin allergy exists:

• Clopidogrel 75 mg daily is the preferred alternative 1, 2
• This recommendation is based on the CAPRIE trial showing clopidogrel's 8.6% relative risk reduction compared to aspirin in high-risk vascular patients 1

For aspirin intolerance (not true allergy):

• Clopidogrel 75 mg daily remains the recommended substitute 1
• Warfarin (INR 2.5-3.5) can be considered as a second-line alternative in patients under 75 years at low bleeding risk, though this requires careful monitoring 1

Dual Antiplatelet Therapy Considerations

After acute coronary syndrome or stent placement:

• Aspirin plus a P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor) for at least 12 months is mandatory 1, 2
• After 12 months, transition to aspirin monotherapy 75-100 mg daily for lifelong secondary prevention 1, 2

For stable chronic coronary syndrome without recent intervention:

• Aspirin monotherapy 75-100 mg daily is sufficient 1, 2
• Dual antiplatelet therapy is not recommended for stable disease due to increased bleeding risk without proportional benefit 1

Special Populations

Peripheral arterial disease:

• Aspirin 75-325 mg daily or clopidogrel 75 mg daily are equally acceptable first-line options 1
• For high ischemic risk patients with non-high bleeding risk, consider rivaroxaban 2.5 mg twice daily plus aspirin 100 mg daily 1

Cerebrovascular atherosclerosis with prior stroke/TIA:

• Aspirin 75-325 mg daily, clopidogrel 75 mg daily, or aspirin plus extended-release dipyridamole (25/200 mg twice daily) are all acceptable 1
• Combination aspirin plus extended-release dipyridamole is preferred over aspirin alone based on superior stroke prevention 1

Asymptomatic carotid/vertebral atherosclerosis:

• Antiplatelet therapy is recommended over anticoagulation 1
• Aspirin 75-325 mg daily is the standard approach 1

Critical Contraindications and Warnings

Do not use aspirin if:

• Active gastrointestinal bleeding or recent major bleeding 1
• True aspirin allergy (anaphylaxis, urticaria) 1
• Severe uncontrolled hypertension 1

Avoid ibuprofen:

• Ibuprofen blocks aspirin's antiplatelet effects and should not be used concurrently 1

Monitoring and Follow-up

• No routine platelet function testing is recommended for aspirin therapy monitoring 4
• Assess medication adherence, bleeding symptoms, and cardiovascular risk factors at every visit 1, 2
• Continue aspirin indefinitely—discontinuation significantly increases thrombotic event risk 1, 2

Common Pitfalls to Avoid

• Do not use enteric-coated aspirin preferentially—it may reduce bioavailability and antiplatelet effect compared to plain aspirin 1
• Do not stop aspirin perioperatively without compelling indication—the thrombotic risk typically outweighs bleeding risk 1
• Do not combine aspirin with clopidogrel in stable chronic disease—this increases bleeding without improving outcomes 1
• Do not use aspirin for primary prevention in adults ≥60 years—the bleeding risk exceeds cardiovascular benefit 5