What is the recommended heparin (unfractionated heparin) drip protocol for a patient pending left heart catheterization (left heart cath)?

Heparin Protocol for Left Heart Catheterization

For patients pending left heart catheterization, administer an initial unfractionated heparin bolus of 100 U/kg (maximum 5000 U) followed by monitoring of ACT to maintain levels >200 seconds during the procedure. 1

Initial Dosing

• Initial bolus: 100 U/kg unfractionated heparin (maximum 5000 U) administered intravenously at the start of the procedure 1
• For prolonged procedures (>60 minutes), additional boluses or a continuous infusion should be used to maintain adequate anticoagulation 1
• Target ACT: >200 seconds for standard procedures; consider higher targets (250-300 seconds) for high-risk thrombotic procedures 1

Monitoring Protocol

• Measure ACT approximately 1 hour after the initial bolus and then every 30 minutes for longer procedures 1
• Administer additional heparin (50-100 U/kg) as needed to maintain ACT >200 seconds 1
• For interventional procedures with higher thrombotic risk, consider maintaining ACT between 250-300 seconds 1

Special Considerations

• Weight-based dosing is critical as fixed-dose protocols may result in significant over or under-anticoagulation 1
• For patients with renal impairment, no dose adjustment is required for unfractionated heparin (unlike LMWH) 1
• If the patient has a history of heparin-induced thrombocytopenia (HIT), alternative anticoagulation strategies must be used 1

Post-Procedure Management

• After completion of the procedure, heparin effect typically wanes without specific reversal 1
• If immediate reversal is needed, protamine can be administered (1 mg of protamine per 100 units of heparin given in the preceding 2-3 hours) 1
• Monitor for post-procedure arterial thrombosis, particularly in pediatric patients or those with small vessels 1

Alternative Anticoagulants

• For patients with HIT, bivalirudin is the preferred alternative:
  • Coronary angiography dosing: IV bolus of 0.75 mg/kg followed by infusion at 1.75 mg/kg/hour during the procedure 1
  • If ACT <225 seconds after bolus, increase infusion rate by 0.25 mg/kg/hour 1
  • For patients with moderate renal impairment (CrCl 30-59 mL/min), start infusion at 1.4 mg/kg/hour 1

Common Pitfalls

• Inadequate initial dosing leading to subtherapeutic anticoagulation and increased thrombotic risk 1
• Failure to monitor ACT during prolonged procedures, resulting in inconsistent anticoagulation 1
• Using heparin flush alone without proper bolus dosing, which fails to provide adequate anticoagulation 1
• Not accounting for patient-specific factors such as weight, which can lead to inappropriate dosing 2
• Overlooking the possibility of HIT in patients with previous heparin exposure 1

Remember that proper anticoagulation during left heart catheterization is essential to prevent thromboembolic complications while balancing the risk of bleeding. The protocol outlined above represents the standard approach based on current guidelines and evidence.