How long should enoxaparin be continued after percutaneous coronary intervention, and how do high‑risk features or renal impairment modify the duration?

Duration of Enoxaparin After PCI

Enoxaparin should be discontinued immediately after successful PCI completion, as it serves only as procedural anticoagulation and is not continued post-procedure. 1, 2

Procedural Anticoagulation Only

• Enoxaparin is used solely for periprocedural anticoagulation during PCI, not as post-procedural therapy. 1
• After PCI, patients transition to dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor like clopidogrel) as the primary antithrombotic strategy, with aspirin continued indefinitely and clopidogrel for at least 12 months after stent placement. 1
• The ACC/AHA guidelines explicitly state that enoxaparin dosing is "at the time of PCI" with no recommendation for continuation beyond the procedure itself. 1

Dosing Strategy During PCI Based on Prior Enoxaparin Administration

The duration concept relates to timing of the last subcutaneous dose before PCI, not continuation after PCI:

If Last SC Dose Was <8 Hours Before PCI

• No additional enoxaparin is needed—adequate anticoagulation persists from the subcutaneous dose. 1, 2
• Patients can proceed directly to PCI without supplemental anticoagulation. 1

If Last SC Dose Was 8-12 Hours Before PCI

• Administer 0.3 mg/kg IV enoxaparin immediately before or during PCI to restore therapeutic anticoagulation levels. 1, 2
• This supplemental dose maintains anti-Xa levels >0.5 IU/mL for the procedural duration. 3

If Last SC Dose Was >12 Hours Before PCI

• Treat as de novo anticoagulation—either full-dose UFH (with ACT monitoring) or 0.5-0.75 mg/kg IV enoxaparin. 1
• The prior subcutaneous enoxaparin is considered to have insufficient residual effect. 1

Post-PCI Management

• Sheath removal can occur 4 hours after the last IV enoxaparin dose or 6-8 hours after the last SC dose. 1
• No post-procedural enoxaparin infusion or additional doses are recommended after successful PCI. 1
• Patients should be monitored for bleeding complications and recurrent ischemia during the immediate post-procedure period, but anticoagulation is discontinued. 1

Critical Safety Considerations

Avoid "Stacking" Anticoagulants

• Never administer UFH to patients who received SC enoxaparin within 12 hours of PCI—this "stacking" significantly increases major bleeding risk. 1
• The SYNERGY trial demonstrated higher bleeding rates in patients who crossed over between anticoagulants. 1

Renal Impairment Modifications

• For creatinine clearance <30 mL/min, reduce enoxaparin to 1 mg/kg SC once daily if used for upstream ACS treatment before PCI. 2, 4
• During PCI itself, no dose adjustment is required for the single IV bolus (0.3 mg/kg supplemental or 0.5-0.75 mg/kg de novo), but observe closely for bleeding. 5
• Enoxaparin clearance decreases by 44% in severe renal impairment, but single procedural doses do not require adjustment. 4

Special Populations

STEMI Patients Post-Fibrinolysis

• If PCI occurs <8 hours after last SC enoxaparin dose, give no additional enoxaparin. 1, 2
• If PCI occurs >8 hours after last SC dose, administer 0.3 mg/kg IV bolus. 1, 2
• For STEMI patients managed medically (no PCI), enoxaparin continues for 8 days or until hospital discharge, whichever comes first. 2

Patients ≥75 Years with STEMI

• Use 0.75 mg/kg SC every 12 hours (no IV bolus at initiation) for upstream treatment. 2
• The same PCI supplementation rules apply (0.3 mg/kg IV if >8 hours from last dose). 2

Common Pitfalls to Avoid

• Do not continue enoxaparin as a "bridge" after PCI—this is not indicated and increases bleeding risk without benefit. 1
• Do not use fondaparinux as sole anticoagulation during PCI—it causes catheter thrombosis and requires supplemental UFH or bivalirudin. 1
• Do not measure ACT to guide enoxaparin dosing—low-molecular-weight heparins do not significantly affect ACT measurements. 1