Role in the EP lab
Aspirin is rarely the reason a patient is in the lab, but it’s frequently in the medication list and it changes the bleeding calculus. The recurring questions are: does this patient need it continued (coronary stents, recent ACS, established atherosclerotic disease), and what does combining it with an anticoagulant do to the pocket or access site.
Critically, aspirin is not a stroke-prevention strategy for atrial fibrillation. Trials show it is inferior to oral anticoagulation and carries bleeding risk without commensurate benefit; it should not be offered as a “lighter” alternative to anticoagulation in AF.
Mechanism
Aspirin irreversibly acetylates cyclooxygenase-1 in platelets, blocking thromboxane A2 production and thereby platelet aggregation. Because platelets cannot regenerate the enzyme, the effect persists for the platelet lifespan (~7–10 days) and recovers only as new platelets are produced — roughly 10–15% turnover per day.
Dosing
- 81 mg daily for chronic cardiovascular prevention
- 162–325 mg loading dose in acute coronary syndromes
- Higher doses add GI toxicity without more antiplatelet effect
Periprocedural management
- Continue for secondary prevention (recent stent, ACS, high-risk CAD) through most device implants and ablations — interrupting it to avoid a hematoma can trade a manageable bleed for a stent thrombosis or MI
- Dual antiplatelet therapy (DAPT) and antiplatelet + anticoagulant combinations are the real hematoma drivers — coordinate with the managing cardiologist on whether a component can be safely paused, and use meticulous hemostasis
- Aspirin alone is not a reason to delay an urgent procedure
Bleeding considerations
- Additive with anticoagulants and other antiplatelets — the more agents, the higher the pocket-hematoma and access-site bleeding risk
- No specific reversal agent; platelet transfusion is the option for life-threatening bleeding, recognizing transfused platelets are also exposed to any circulating drug
Common pitfalls
- Treating aspirin as adequate AF anticoagulation — it isn’t.
- Stopping aspirin in a patient with a recent coronary stent to “be safe” for a pacemaker — that’s the dangerous move.
- Forgetting that the antiplatelet effect lingers ~a week after the last dose.