In what conditions can Low Molecular Weight Heparin (LMWH) be stopped in patients with Congenital Heart Disease (CHD)?

When to Stop LMWH in Congenital Heart Disease

LMWH should be stopped in congenital heart disease patients when adequate hemostasis is achieved after surgery (typically 1-2 days postoperatively), when transitioning to oral anticoagulation with therapeutic INR levels, when heparin-induced thrombocytopenia (HIT) is suspected or confirmed, or when major bleeding complications occur. 1

Perioperative Management

Stopping Before Procedures

• Discontinue LMWH at least 12 hours before any surgical or interventional procedure to minimize bleeding risk 1
• For high-risk cardiac procedures, stop LMWH 24 hours prior to allow adequate clearance 1
• Check INR on the day of procedure if bridging from warfarin; postpone if INR >1.5 1

Resuming After Surgery

• Resume LMWH 1-2 days after surgery depending on hemostatic status, but at minimum 12 hours post-procedure 1
• In congenital heart disease patients with systemic-to-pulmonary shunts, transition from continuous heparin infusion to LMWH once surgical bleeding concerns resolve 1
• Continue LMWH until oral anticoagulants reach therapeutic INR levels (typically 2-3 days) 1

Transitioning to Long-Term Anticoagulation

Bridging to Warfarin

• Stop LMWH only when INR returns to therapeutic range (2.5-3.5 for mechanical valves, 2.0-3.0 for other indications) 1
• Overlap LMWH with warfarin for minimum 5 days and until INR therapeutic for 24 hours 1
• In pregnant patients with mechanical valves requiring warfarin, LMWH can be stopped at 36 weeks gestation when transitioning delivery planning 1

Transitioning to Aspirin

• In pediatric patients with systemic-to-pulmonary shunts, transition from LMWH to long-term low-dose aspirin once early postoperative thrombotic risk period passes (typically 5-7 days) 1
• Aspirin alone is recommended for long-term thromboprophylaxis in polytetrafluoroethylene shunts 1

Emergency Discontinuation

Heparin-Induced Thrombocytopenia (HIT)

• Immediately stop all forms of heparin (including LMWH) if HIT is suspected based on 4T score, without waiting for laboratory confirmation 1, 2, 3
• Cardiac surgery patients on LMWH have intermediate HIT risk (0.1-1%), requiring platelet monitoring once to twice weekly 1, 2
• Never restart any heparin product if HIT confirmed; use alternative anticoagulants (argatroban, bivalirudin, fondaparinux) 3

Major Bleeding

• Stop LMWH immediately for any major bleeding event including hemoptysis, gastrointestinal bleeding, or intracranial hemorrhage 3
• For life-threatening bleeding, protamine sulfate provides partial reversal (approximately 60% neutralization of anti-Xa activity) 1, 3
• Consider restarting anticoagulation within 1-3 days for high thrombotic risk conditions once hemostasis achieved 3

Duration-Based Discontinuation

Completed Treatment Course

• Stop LMWH after completing intended treatment duration for venous thromboembolism (typically 3-6 months) or other thrombotic complications 4
• In pediatric congenital heart disease, treatment duration averages 14 days for acute thrombotic events 5
• For prophylaxis in high-risk congenital heart disease patients, continue until risk factors resolve 1

Low Thrombotic Risk Procedures

• LMWH can be interrupted for up to 1 week for low-bleeding-risk procedures (e.g., cataract surgery) without bridging in patients without mechanical valves 1
• Resume at pre-procedural dose once hemostasis adequate 1

Special Considerations in Congenital Heart Disease

Cardiac Catheterization

• Stop prophylactic LMWH and use UFH bolus (100 U/kg) instead for procedural anticoagulation during cardiac catheterization due to UFH's shorter half-life and reversibility 1
• LMWH offers no practical advantages over UFH during catheterization procedures 1

Pregnancy with Congenital Heart Disease

• In pregnant patients with mechanical valves, stop LMWH at 36 weeks gestation and transition to UFH or warfarin for delivery planning 1
• Measure anti-Xa levels 4-6 hours post-dose throughout pregnancy; adjust dosing as weight increases 1, 6
• Target anti-Xa levels: 0.7-1.2 units/mL for twice-daily therapeutic dosing 1, 6

Common Pitfalls to Avoid

• Do not stop LMWH without alternative anticoagulation in high-risk patients (mechanical valves, recent thrombosis <3 months, known thrombophilia) 1
• Do not continue LMWH while awaiting HIT laboratory results if clinical suspicion is intermediate or high 2, 3
• Do not assume therapeutic levels without monitoring in neonates and infants, who require higher doses (1.6 mg/kg vs 1.0 mg/kg) due to increased clearance 5, 7
• Do not use aPTT to monitor LMWH; use anti-Xa levels instead 6
• Renal impairment significantly prolongs LMWH half-life; dose reduction or discontinuation may be necessary 6