When should aspirin, low‑molecular‑weight heparin (enoxaparin), and clopidogrel be held before a surgical procedure in an adult on dual antiplatelet therapy, considering the procedure’s bleeding risk and impaired renal function?

When to Hold Aspirin, Enoxaparin, and Clopidogrel Before Surgery

For most surgical procedures, continue aspirin throughout the perioperative period, stop clopidogrel 5 days before surgery, and discontinue enoxaparin 24 hours preoperatively (or longer if renal impairment exists), unless the patient has a recent coronary stent (<6 months for drug-eluting, <4-6 weeks for bare-metal), in which case both aspirin and clopidogrel must be continued despite bleeding risk. 1, 2, 3

Aspirin Management

Continue aspirin perioperatively in the vast majority of cases, particularly for patients with:

• Prior myocardial infarction or stroke 3
• Any coronary stent (regardless of timing) 1, 3
• Moderate-to-high cardiovascular risk 3

Stop aspirin only in highly selected circumstances:

• Low cardiovascular risk patients undergoing procedures where even minor bleeding is catastrophic (intracranial surgery, spinal cord surgery, posterior chamber eye surgery) 4, 5
• If stopping aspirin, discontinue ≤7 days before surgery 3
• For minor procedures (dental, dermatologic, cataract surgery), always continue aspirin 3

The thrombotic risk of discontinuing aspirin typically outweighs the modest increase in surgical bleeding for most procedures. 2, 6

Clopidogrel Management

Stop clopidogrel 5 days before surgery in patients without recent stents, as it irreversibly inhibits platelet aggregation for the platelet's 7-10 day lifespan. 1, 2, 6, 3

Critical exception—continue clopidogrel if:

• Drug-eluting stent placed within 6-12 months 6, 3
• Bare-metal stent placed within 4-6 weeks 6, 3
• Recent acute coronary syndrome (within 6 months) 1

In these high-risk scenarios, both aspirin and clopidogrel must be maintained throughout the perioperative period, as stent thrombosis carries a 10% risk of major vascular events including death, which far exceeds surgical bleeding risk. 2, 4

For elective surgery requiring clopidogrel discontinuation:

• Defer surgery until at least 1 month after any stent implantation if aspirin can be maintained 1
• Ideally postpone elective surgery for 6 months after drug-eluting stent or acute coronary syndrome 1, 3

Enoxaparin (Low-Molecular-Weight Heparin) Management

Discontinue enoxaparin based on renal function and bleeding risk:

For normal renal function (CrCl >60 mL/min):

• Stop therapeutic-dose enoxaparin (1 mg/kg twice daily) at least 24 hours before surgery 1
• Last dose should be given no later than 24 hours preoperatively

For impaired renal function:

• CrCl 30-60 mL/min: Stop 36-48 hours before surgery
• CrCl <30 mL/min: Stop 48-72 hours before surgery (enoxaparin accumulates significantly)

Critical caveat: Enoxaparin provides anticoagulation, not antiplatelet protection. Never substitute enoxaparin for aspirin or clopidogrel in patients with coronary stents, as anticoagulants do not prevent stent thrombosis and actually increase bleeding risk without adequate platelet inhibition. 6, 4

Neuraxial Anesthesia Considerations

Aspirin alone is not a contraindication to spinal or epidural anesthesia if no other hemostatic abnormalities exist. 3

Absolute contraindications to neuraxial blockade:

• Any P2Y12 inhibitor (clopidogrel) unless discontinued for full 5-day duration 3
• Enoxaparin within 24 hours (therapeutic dose) or 12 hours (prophylactic dose)

Postoperative Resumption Protocol

Resume antiplatelet therapy within 24 hours after surgery once adequate hemostasis is achieved:

• Restart aspirin at maintenance dose (75-100 mg daily) 1, 3
• Restart clopidogrel at standard 75 mg daily (consider 300 mg loading dose in high-risk patients with recent stents) 2, 3
• Resume enoxaparin when surgical bleeding risk has stabilized, typically 12-24 hours postoperatively

The European Society of Cardiology emphasizes that early resumption is critical given the substantial thrombotic hazard associated with lack of platelet inhibition after surgery in patients with recent stent implantation or acute coronary syndrome. 1

Common Pitfalls to Avoid

Never discontinue both aspirin and clopidogrel simultaneously in patients with recent stents, as this dramatically increases stent thrombosis mortality beyond surgical bleeding risk. 2, 6

Do not use heparin or enoxaparin bridging as a substitute for antiplatelet therapy, as this strategy increases bleeding without protecting against arterial or stent thrombosis. 2, 4

Avoid excessive preoperative delay beyond the recommended 5-day clopidogrel discontinuation period, as this increases thrombotic risk without additional hemostatic benefit. 2

Do not transfuse platelets prophylactically—only administer to patients with active abnormal bleeding thought related to persisting antiplatelet effects. 5