Is daily low-dose (81 mg) aspirin considered antiplatelet therapy for a patient with a <2 cm femoral pseudo‑aneurysm identified nine days after cardiac catheterisation who is already on antiplatelet/anticoagulant therapy?

Is Daily Baby Aspirin Considered Antiplatelet Therapy?

Yes, daily low-dose aspirin (81 mg, commonly called "baby aspirin") is definitively antiplatelet therapy and functions by irreversibly inhibiting platelet cyclooxygenase-1 enzyme and blocking thromboxane A2 production, thereby preventing platelet aggregation. 1

Mechanism and Dosing

Low-dose aspirin at 75-100 mg daily (81 mg in the United States) exceeds the minimal effective dose required for complete platelet thromboxane A2 suppression. 1 This dose range provides:

• Near-complete inhibition of arachidonic acid-induced platelet aggregation 1
• Maximal antiplatelet effect while minimizing bleeding complications compared to higher doses 1
• Equivalent cardiovascular protection to higher doses (162-325 mg) without the increased gastrointestinal bleeding risk 1

Evidence-Based Clinical Applications

The 2025 ACC/AHA guidelines explicitly classify aspirin 75-100 mg daily as antiplatelet therapy across multiple cardiovascular conditions:

• Acute coronary syndromes: Loading dose 162-325 mg followed by maintenance 75-100 mg daily 1
• Post-stent placement: Continued indefinitely as Class I recommendation (highest evidence level) 1, 2
• Secondary prevention after MI: Reduces serious vascular events by approximately 25%, preventing 36 events per 1,000 patients over 2 years 1, 3

Relevance to Your Clinical Scenario

For a patient with a femoral pseudoaneurysm post-cardiac catheterization who is already on antiplatelet/anticoagulant therapy:

The aspirin they are taking IS antiplatelet therapy and should be considered when planning pseudoaneurysm management. 4, 5 Research demonstrates that:

• Ultrasound-guided thrombin injection successfully treats pseudoaneurysms in 87.5-92% of cases even in patients continuing aspirin therapy 4, 5
• In one study of 64 patients, 63 were on aspirin and antithrombotic therapy was not discontinued during pseudoaneurysm closure procedures 5
• The presence of antiplatelet therapy does not preclude non-surgical treatment options 6, 7

Critical Clinical Pitfall

Do not discontinue aspirin in patients with recent cardiac catheterization or coronary stents, as aspirin withdrawal increases risk of acute coronary syndrome and stent thrombosis. 2, 3 The cardiovascular risk of stopping aspirin typically outweighs the bleeding risk from the pseudoaneurysm itself. 3

For your specific patient, the 81 mg daily aspirin represents active antiplatelet therapy that must be factored into treatment decisions, but modern pseudoaneurysm management techniques (particularly ultrasound-guided thrombin injection) are highly effective despite ongoing antiplatelet therapy. 4, 5, 6