Should Acetylsalicylic Acid (ASA) and Clopidogrel (Plavix) be held before a heart catheterization?

Should ASA and Plavix Be Held Before Heart Catheterization?

No, ASA (aspirin) and Plavix (clopidogrel) should NOT be held before diagnostic heart catheterization. Both medications should be continued through the procedure, as the thrombotic risk of discontinuation substantially outweighs any bleeding risk during diagnostic catheterization 1.

Key Management Principles

For Diagnostic Catheterization Only

• Continue both ASA and clopidogrel through diagnostic heart catheterization without interruption 1
• The decision about whether to proceed with PCI can be made after visualizing the coronary anatomy 1
• If PCI is performed, clopidogrel loading can be administered in the catheterization laboratory if the patient was not already on the medication 1

When CABG May Be Needed

The management strategy differs based on clinical urgency and whether CABG is anticipated:

For patients in whom diagnostic catheterization is planned within 24-36 hours and CABG cannot be excluded:

• It is reasonable to withhold clopidogrel until coronary angiography excludes the need for urgent CABG 1
• However, ASA should be continued 1
• The clopidogrel loading dose can then be given in the catheterization laboratory prior to PCI or immediately after catheterization if no intervention is needed 1

For unstable patients:

• Clopidogrel should be administered immediately, or the patient should be taken for immediate angiography 1
• The thrombotic risk in unstable patients outweighs concerns about potential CABG 1

If CABG Is Required After Catheterization

Timing Recommendations

• Clopidogrel should be withheld for at least 5 days, and preferably 7 days, before elective CABG 1, 2
• This allows adequate platelet function recovery, as clopidogrel causes irreversible platelet inhibition for the lifetime of the platelet (7-10 days) 2

ASA Management for CABG

• ASA should generally be continued perioperatively for CABG 1
• While ASA increases postoperative bleeding (measured by chest tube drainage), it does not increase the need for reoperation and is associated with reduced cardiovascular events and overall mortality 1
• ASA may only be stopped in patients with stable coronary artery disease requiring CABG where bleeding risk is particularly high 1

When Urgent CABG Cannot Wait

• In the CRUSADE Registry, 30% of UA/NSTEMI patients received clopidogrel within 5 days of CABG 1
• "Early" CABG after clopidogrel was associated with increased transfusion requirements (50% higher major bleeding, 70% higher transfusion needs) but no difference in mortality, reinfarction, or stroke 1
• Some experienced surgeons can perform CABG at acceptable incremental bleeding risk even with recent clopidogrel exposure 1

Critical Thrombotic Risk Considerations

For Patients with Coronary Stents

• Elective surgery should be deferred for 6 weeks after bare-metal stent placement and 6 months after drug-eluting stent placement 1
• If surgery must occur within these timeframes, continue antiplatelet therapy perioperatively rather than stopping it 1
• The risk of stent thrombosis with premature antiplatelet discontinuation carries a case-fatality rate of approximately 50% 1

For Acute Coronary Syndrome Patients

• Clopidogrel should ideally not be discontinued within the first 12 months after acute coronary syndrome, as the thrombotic risk is prohibitively high 3
• Discontinuation of clopidogrel increases the risk of cardiovascular events and should be avoided whenever possible 2

Common Pitfalls to Avoid

• Do not routinely hold clopidogrel before diagnostic catheterization - this outdated practice increases thrombotic risk unnecessarily 1, 4
• Do not substitute heparin or low-molecular-weight heparin for antiplatelet therapy - these agents do not provide protection against coronary artery or stent thrombosis 4
• Do not abruptly discontinue antiplatelet therapy without cardiology consultation - patients should contact their treating cardiologist before stopping any antiplatelet medication 1
• Ensure adequate medication reconciliation - patients may not report over-the-counter NSAIDs with antiplatelet effects 5

Resumption After Any Necessary Interruption

• When clopidogrel must be temporarily discontinued, restart it as soon as possible after the procedure 2
• Resume clopidogrel as soon as hemostasis is achieved, typically within 12-24 hours 1, 2
• ASA should be resumed within 24 hours when adequate hemostasis has been achieved 1, 5