Perioperative Anticoagulation Management

Introduction to Heparinization Risks

Excessive preoperative heparinization before cardiopulmonary bypass significantly increases the risk of perioperative bleeding complications, which can lead to increased morbidity and mortality 1
High protamine-to-heparin ratios (>1.0) are associated with coagulation abnormalities, impaired restoration of post-protamine thrombin levels, and enhanced postoperative bleeding 1

Target ACT above 480 seconds during CPB with uncoated equipment 1
Maintain protamine-to-heparin ratio between 0.8-1.0 of the initial heparin dose 1
Higher heparin exposure increases the risk of developing anti-PF4/heparin antibodies, and when anti-PF4 antibody titers are elevated (OD >1.5), clinical risk is higher with heparin re-exposure 2

For patients with contraindications to heparin (e.g., HIT), direct thrombin inhibitors like bivalirudin or argatroban can be used, with bivalirudin dosing: IV bolus of 1 mg/kg + 50 mg in pump priming fluid, then IV infusion at 2.5 mg/kg/hour during CPB 2
For patients with HIT but requiring heparin for CPB, consider intravenous antiplatelet agents (tirofiban or cangrelor) combined with heparin, or plasma exchange to minimize circulating antibodies 2