Can I change the heparin (anticoagulant) infusion dose from 1000 units at 2ml/hr to 2500IU four times a day (QID) in a patient with an intra-aortic balloon pump (IABP) who is scheduled for coronary artery bypass grafting (CABG) surgery tomorrow?

Management of Heparin Infusion Before CABG Surgery

You should continue the unfractionated heparin (UFH) infusion at the current dose of 1000 units at 2ml/hr until the CABG procedure, rather than changing to intermittent dosing of 2500IU QID. 1

Rationale for Continuing Current Heparin Infusion

• For patients with an intra-aortic balloon pump (IABP) who are scheduled for CABG, guidelines specifically recommend continuing unfractionated heparin infusion until surgery 1
• The ACC/AHA guidelines clearly state that for patients in whom CABG is selected as a management strategy, anticoagulant therapy should be managed by continuing UFH 1
• Continuous infusion provides more stable anticoagulation levels compared to intermittent dosing, which is particularly important in a patient with an IABP 1

Importance of Continuous Anticoagulation with IABP

• Patients with an IABP require continuous anticoagulation to prevent thrombus formation on the device surface 1
• Switching to intermittent dosing (2500IU QID) may lead to fluctuating anticoagulation levels with periods of subtherapeutic coverage, increasing thrombosis risk 2
• The current continuous infusion regimen provides more predictable anticoagulation, which is critical for IABP management 1

Perioperative Anticoagulation Management

• UFH is the preferred anticoagulant for patients proceeding to CABG as it has a short half-life (60-90 minutes) allowing for easier management during surgery 3
• Unlike other anticoagulants that require discontinuation before surgery (enoxaparin: 12-24 hours; fondaparinux: 24 hours; bivalirudin: 3 hours), UFH infusion can be continued until the procedure 1
• The surgical team can simply stop the infusion when needed during the procedure, providing flexibility in timing 1

Monitoring Recommendations

• Continue to monitor activated partial thromboplastin time (aPTT) to ensure therapeutic anticoagulation (target: 1.5-2 times normal) 4
• Monitor platelet counts regularly to detect potential heparin-induced thrombocytopenia, especially in patients receiving heparin for several days before surgery 5
• Consider checking hemoglobin levels and monitoring for any signs of bleeding 1

Common Pitfalls to Avoid

• Changing from continuous to intermittent dosing may lead to inconsistent anticoagulation levels and increased risk of thrombotic complications with the IABP 2
• Increasing the dose unnecessarily may increase bleeding risk during surgery 1
• Discontinuing anticoagulation completely before surgery in a patient with an IABP could lead to device thrombosis 1

Special Considerations

• If the patient has received prolonged heparin therapy, they may exhibit reduced heparin responsiveness during surgery, potentially requiring higher doses during cardiopulmonary bypass 6
• The surgical team should be informed about the patient's current anticoagulation status to prepare accordingly for the procedure 1
• Postoperatively, aspirin therapy should be initiated or continued for all CABG patients, ideally within 6 hours after surgery 1