Do Not Stop Heparin Infusion Before PCI
Heparin infusion should be continued and administered during PCI, not stopped beforehand. The question appears to reflect a misunderstanding of standard anticoagulation practice during percutaneous coronary intervention.
Standard Anticoagulation Protocol During PCI
For Patients NOT on Prior Heparin
According to ACC/AHA/SCAI guidelines, patients undergoing PCI who have not received prior anticoagulation should receive 1:
- Without planned GP IIb/IIIa inhibitor: 70-100 U/kg IV bolus to achieve ACT 250-300 seconds (HemoTec) or 300-350 seconds (Hemochron)
- With planned GP IIb/IIIa inhibitor: 50-70 U/kg IV bolus to achieve ACT 200-250 seconds
For Patients Already on Heparin Infusion
If a patient is already receiving heparin infusion, additional heparin should be administered as needed during PCI (typically 2,000-5,000 units) to achieve target ACT levels 1. The existing infusion provides baseline anticoagulation, but procedural boluses are required to reach therapeutic ACT targets for the intervention itself.
Post-PCI Heparin Management: When to Actually Stop
The critical timing question is not before PCI, but rather after PCI:
Evidence Against Post-PCI Heparin Continuation
Heparin infusion should be discontinued after successful PCI completion. Recent high-quality evidence demonstrates:
- Post-PCI heparin continuation in ACS patients was associated with significantly increased bleeding risk (4.75% vs 2.52%, adjusted HR 1.69, p=0.007) 2
- No cardiovascular benefit was observed—in fact, there was a numerically increased risk of cardiovascular events (3.16% vs 1.72%, adjusted HR 1.56, p=0.06) 2
- An earlier randomized trial showed routine post-procedure heparin increased bleeding without reducing ischemic complications 3
FDA-Approved Discontinuation Practice
The FDA label supports discontinuation after PCI, stating that when converting from heparin to oral anticoagulants, "stop intravenous infusion of heparin sodium immediately after administering the first dose of oral anticoagulant" 4. Full-dose anticoagulation is no longer used after successful PCI procedures 1.
Clinical Algorithm
Before PCI:
- Continue any existing heparin infusion
- Administer weight-based bolus per guidelines to achieve target ACT
During PCI:
- Monitor ACT levels
- Give additional boluses (2,000-5,000 units) as needed to maintain target ACT 1
After PCI:
- Stop heparin infusion once procedure is successfully completed
- Remove femoral sheaths when ACT falls to 150-180 seconds 1
- Do not continue routine post-procedural heparin 3, 2
Important Caveats
Exceptions where post-PCI anticoagulation may continue:
- Specific indications such as atrial fibrillation, mechanical heart valves, or left ventricular thrombus
- Mechanical circulatory support devices in place
- Ongoing acute coronary syndrome with planned staged procedures
The 2015 ESC/ACC-AHA guidelines for primary PCI recommend unfractionated heparin as Class I (must be used in patients not receiving bivalirudin or enoxaparin) but do not advocate for routine post-procedural continuation 5.
The evidence is clear: stopping heparin before PCI would be inappropriate and dangerous, while stopping it after successful PCI is the evidence-based standard of care.