When should antiplatelet therapy be stopped in a patient with a history of coronary artery disease (CAD) or cerebrovascular disease undergoing a below-the-knee amputation?

Perioperative Antiplatelet Management for Below-Knee Amputation

Direct Answer

In patients with CAD or cerebrovascular disease undergoing below-knee amputation, aspirin should generally be continued throughout the perioperative period, while P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor) should be discontinued 3-7 days preoperatively depending on the specific agent, and both should be resumed as soon as hemostasis is achieved postoperatively. 1

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Aspirin Management

Continue aspirin perioperatively unless bleeding risk is prohibitive:

• Aspirin (75-100 mg daily) should be maintained throughout the perioperative period in patients with secondary prevention indications (CAD, prior stroke, or peripheral arterial disease), as the thrombotic risk of discontinuation outweighs bleeding concerns for most procedures 1

• The 2024 AHA/ACC guidelines specifically recommend continuing aspirin in patients with prior PCI undergoing noncardiac surgery to reduce cardiac events 1

• Critical caveat: Patients with lower extremity arterial disease who discontinue aspirin have a 6.1% risk of thrombotic events, with some occurring perioperatively 1

• Aspirin should only be discontinued if the amputation is considered an extremely high bleeding risk procedure where even minor bleeding would be catastrophic 1

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P2Y12 Inhibitor Management

Timing of discontinuation varies by agent:

• Clopidogrel: Discontinue at least 5 days before surgery 1, 2
• Prasugrel: Discontinue at least 7 days before surgery 1
• Ticagrelor: Discontinue at least 3 days before surgery 1

Special considerations for patients with coronary stents:

• If the patient has a drug-eluting stent placed within the past 6 months or bare-metal stent within 30 days, surgery should ideally be delayed if possible, as the risk of stent thrombosis is extremely high 1

• For patients with recent acute coronary syndrome (within 12 months), elective surgery should be postponed if clinically feasible 1

• If surgery cannot be delayed and the patient is within 1 month of stent placement, consider maintaining aspirin while discontinuing the P2Y12 inhibitor, and perform surgery only in hospitals with 24/7 catheterization laboratory availability 1

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Postoperative Resumption

Restart antiplatelet therapy as soon as possible:

• Both aspirin and P2Y12 inhibitors should be resumed within 24-48 hours postoperatively once adequate hemostasis is achieved 1, 3

• The ESC guidelines emphasize resuming therapy "as soon as possible (within 48 hours)" given the substantial thrombotic hazard associated with lack of platelet inhibition 1

• Consider a loading dose of clopidogrel (300 mg) when resuming to achieve faster platelet inhibition 4

• Critical warning: Discontinuation of antiplatelet therapy increases the absolute risk of stroke recurrence or cardiovascular events by approximately 2% within 30 days 3

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Risk Stratification Algorithm

Assess both ischemic and bleeding risks:

1. High ischemic risk features (favor continuing aspirin):

   • Recent stent placement (<6 months for drug-eluting, <30 days for bare-metal) 1
   • Recent MI or ACS (<12 months) 1
   • History of stent thrombosis 5
   • Multiple or complex stents 5
   • Diabetes or low ejection fraction 4

2. Bleeding risk assessment:

   • Below-knee amputation is generally considered moderate bleeding risk 4
   • This allows for aspirin continuation with P2Y12 inhibitor discontinuation 1

3. Decision pathway:

   • If >6 months from stent placement and stable CAD: Continue aspirin, stop P2Y12 inhibitor 5-7 days preoperatively 1
   • If <6 months from stent placement: Multidisciplinary discussion required; consider delaying surgery if possible 1
   • If recent ACS (<12 months): Strong consideration for delaying surgery 1

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Common Pitfalls to Avoid

• Never discontinue both antiplatelet agents simultaneously in patients with recent stents, as this dramatically increases stent thrombosis risk 5

• Do not withhold aspirin indefinitely postoperatively - thrombotic events cluster early after discontinuation with highest risk in first 30 days 3

• Avoid assuming all amputations require complete antiplatelet cessation - the bleeding risk must be weighed against the patient's specific cardiovascular risk profile 1

• Do not restart P2Y12 inhibitors without ensuring aspirin is also continued in patients with coronary stents 3

• Platelet transfusions given within 4 hours of clopidogrel loading dose or 2 hours of maintenance dose may be less effective 2