Should low‑dose aspirin, therapeutic enoxaparin (Lovenox), or PCSK9‑inhibitor therapy be held prior to an elective cardiac catheterization?

Aspirin, Enoxaparin, and PCSK9 Inhibitors Before Cardiac Catheterization

Continue aspirin through cardiac catheterization without interruption; enoxaparin should be continued with appropriate timing adjustments based on the last dose; PCSK9 inhibitors do not need to be held.

Aspirin Management

Aspirin should never be stopped before cardiac catheterization. 1

• Patients already on chronic aspirin therapy should continue their usual dose (75-325 mg daily) without any interruption before the procedure 1
• For patients not currently taking aspirin, administer a loading dose of 325 mg non-enteric aspirin before PCI, ideally at least 2 hours and preferably 24 hours prior to the procedure 1
• After catheterization, continue aspirin 81 mg daily indefinitely, as this lower maintenance dose minimizes bleeding risk while preserving antiplatelet efficacy 2, 1
• The evidence is unequivocal: aspirin continuation is a Class I recommendation (strongest level) for all patients undergoing PCI 2, 1

Why Aspirin Must Be Continued

• Discontinuing aspirin before catheterization increases the risk of acute coronary events, particularly in patients with established coronary disease 3
• Studies show that aspirin withdrawal precedes up to 10.2% of acute cardiovascular syndromes, with events occurring as early as 8.5 days after discontinuation 3
• For diagnostic catheterization that may proceed to PCI, maintaining aspirin ensures readiness for immediate intervention without delay 1

Enoxaparin (Lovenox) Management

Enoxaparin should be continued but requires dose timing adjustments based on when the last dose was administered. 2

• If the patient received fewer than 2 therapeutic subcutaneous doses (1 mg/kg) OR the last dose was given 8-12 hours before PCI, administer an additional 0.3 mg/kg IV enoxaparin at the time of the procedure 2
• Patients on therapeutic subcutaneous enoxaparin can safely undergo PCI without switching to unfractionated heparin 2
• Critical pitfall to avoid: Do NOT administer unfractionated heparin to patients already receiving therapeutic subcutaneous enoxaparin, as this combination is contraindicated (Class III: Harm recommendation) 2
• After uncomplicated PCI, discontinue anticoagulant therapy 2

For Patients Requiring Ongoing Anticoagulation

• If the patient needs oral anticoagulation (e.g., atrial fibrillation), enoxaparin can be bridged appropriately, but the specific management depends on the indication and bleeding risk 4
• Resume oral anticoagulation within 24 hours post-PCI after assessing hemostasis at the access site 4

PCSK9 Inhibitor Management

PCSK9 inhibitors (evolocumab, alirocumab) do not need to be held before cardiac catheterization.

• These are lipid-lowering monoclonal antibodies with no impact on coagulation, platelet function, or procedural bleeding risk
• Continue PCSK9 inhibitors on their regular dosing schedule (typically every 2 weeks or monthly) regardless of catheterization timing
• There is no guideline recommendation to discontinue PCSK9 inhibitors perioperatively because they pose no thrombotic or hemorrhagic risk

Dual Antiplatelet Therapy Considerations

If the catheterization proceeds to PCI with stenting, additional antiplatelet therapy will be required:

• Administer a loading dose of a P2Y12 inhibitor (clopidogrel 600 mg, prasugrel, or ticagrelor 180 mg) in addition to aspirin 1
• Continue dual antiplatelet therapy (aspirin + P2Y12 inhibitor) for at least 12 months after stent placement in acute coronary syndrome patients 2, 1
• For patients already on oral anticoagulation who undergo PCI, the strategy shifts to early aspirin discontinuation (within 1 week) and continuation of oral anticoagulant plus clopidogrel (dual therapy) to reduce bleeding risk 4

Common Pitfalls to Avoid

• Never stop aspirin before catheterization, even in patients perceived to be at high bleeding risk—the thrombotic risk far outweighs any bleeding concern 2, 1
• Do not give UFH to patients on therapeutic enoxaparin—this combination significantly increases bleeding risk without benefit 2
• Do not confuse diagnostic catheterization with other surgical procedures—cardiac catheterization is a vascular procedure where aspirin continuation is mandatory, unlike intracranial neurosurgery where aspirin may need to be held 5
• Do not hold medications unnecessarily—PCSK9 inhibitors have no procedural implications and continuing them avoids gaps in lipid management