Is heparin given during cardiac catheterization?

Heparin Administration During Cardiac Catheterization

Yes, heparin is routinely administered during cardiac catheterization as standard procedural anticoagulation to prevent thrombotic complications. The American Heart Association provides Class I recommendations for unfractionated heparin (UFH) use during these procedures 1.

Standard Dosing Protocol

Administer an initial bolus of 100 U/kg unfractionated heparin (maximum 5000 U) intravenously at the time of arterial access 1, 2. This dose most consistently achieves the target activated clotting time (ACT) of >200 seconds 1.

• The 100 U/kg dose is superior to lower doses (50 U/kg) in achieving therapeutic anticoagulation and suppressing fibrinopeptide A levels 1
• Heparin flush alone is inadequate and fails to suppress thrombotic markers 1
• For adult coronary interventions, ACC/AHA/SCAI guidelines recommend 70-100 IU/kg to achieve ACT 250-300 seconds (Hemotec) or 300-350 seconds (Hemochron) when glycoprotein IIb/IIIa inhibitors are not used 3

Monitoring Requirements

Measure ACT approximately 1 hour after the initial bolus, then every 30 minutes during prolonged procedures (>60 minutes) 1, 2.

• Target ACT should be maintained >200 seconds for standard procedures 1, 2
• For high-risk thrombotic procedures, consider higher ACT targets of 250-300 seconds 1, 2, 4
• Administer additional boluses of 50-100 U/kg as needed to maintain therapeutic ACT 1, 2

Important caveat: ACT monitoring is essential because fixed-dose heparin without monitoring may result in significant over- or under-anticoagulation 1. Studies show that 72% of pediatric patients achieve target ACT with 100 U/kg dosing, but individual variation exists 5.

Indications by Access Type

For arterial access procedures: Heparin anticoagulation is mandatory (Class I recommendation) 1.

For venous-only access: Heparin is reasonable (Class IIa) if any of the following apply 1:

• Right-to-left shunt present
• Interventional procedure planned
• Prolonged procedure expected

Post-Procedure Management

Discontinue heparin immediately after uncomplicated procedures 2, 4. There is no evidence supporting routine continuation of heparin after uncomplicated coronary intervention 2.

• Remove arterial sheaths when ACT falls below 180 seconds or 2-4 hours after last heparin dose 4
• Continue heparin for 24 hours only in high-risk scenarios: visible arterial dissections or mural thrombus 4
• If immediate reversal needed, administer protamine 1 mg per 100 units of heparin given in preceding 2-3 hours 2

Common Pitfalls to Avoid

Inadequate initial dosing is the most common error, leading to subtherapeutic anticoagulation and increased thrombotic risk 2. Weight-based dosing is critical—never use fixed doses 1, 2.

Failure to monitor ACT during prolonged procedures results in inconsistent anticoagulation 2. Despite heparin prophylaxis, femoral artery thrombosis still occurs in 3.6% of pediatric cases, with higher rates (39%) in balloon dilation procedures 1.

Hemodilution significantly lowers ACT values during procedures, particularly with crystalloid administration 5. Patients receiving premedication with aspirin or low-molecular-weight heparin may also have lower ACT values 5.

Alternative Anticoagulants

For patients with heparin-induced thrombocytopenia (HIT), bivalirudin is the preferred alternative 2:

• IV bolus 0.75 mg/kg followed by infusion at 1.75 mg/kg/hour 2
• If ACT <225 seconds after bolus, increase infusion by 0.25 mg/kg/hour 2
• For moderate renal impairment (CrCl 30-59 mL/min), reduce infusion to 1.4 mg/kg/hour 2

Low-molecular-weight heparin may be considered but offers no practical advantages over UFH and cannot be easily monitored with ACT 1. Aspirin alone for thromboprophylaxis is not recommended (Class III) 1.