1. The role of anticoagulation in venous shunts
- a brief overview

2. The use of heparin Activates antithrombin III
Typical regime – loading dose of units/kg followed by 28units/kg/hr < 1yr, 20 units/kg/hr >1 yr and 18 unit/kg/hr in older children
Monitoring using APTT (other methods are heparin concentration, anti Factor Xa levels, ACT levels)

3. LMWH Longer t ½ Administered sub-cutaneously
Lower side effects – thrombocytopenia and osteoporosis
Enoxaparin 1.5mg/kg 12h (<2mo) and 1mg/kg 12h (> 2mo)
Reviparin 150units/kg 12h (< 2 mo) and 100 units/kg 12h (> 2 mo)

4. Warfarin etc Inhibits Vit K dependent clotting factors
Oral loading dose 0.2mg/kg then adjusted using INR
Various ranges
2-3 for prophylaxis against TE
for valves
3-4.5 for recurrent TE at lower range
not tested in kids

5. Aspirin Decreases Platelet aggregation Aspirin+cyclo-oxygenase = TXA2
Effect lasts for 7-10 days
3-5mg/kg/day

6. Dipyridamole Inhibits phospho-diesterase cAMP 2-5mg/kg/day
Adjunct therapy in patients with mechanical valves

7. Pentoxiphylline
Enhances RBC flexibility, blood viscosity, platelet aggregation, TNFα
20mg/kg/day
Used in
PVD with marginal improvement in PBF
Kawasaki

8. Glenn and Fontan Use of prosthetic material
Presence of fenestration and R-L shunting
Incidence of TE events 5-33% (retrospective, TTE)
One partially prospective study showed TEE to be superior to TTE and showed an incidence of thrombus formation in 33% of patients.

9. Coagulopathies in Fontan
Liver derangements
Protein C, antithrombin III, Protein S, Plasminogen, Factors II, VII, IX, X, XIII
Factor VIII, plasmin-antiplasmin complex, activated partial thromboplastin time, thrombin- antithrombin III complex, D-dimer, Gamma GT, SGOT/PT

10. Risk factors for development of thrombus
Low post op saturations
Large fenestration
Discordant sized bilateral SVC
Atrial dysrhythmia

11. Warfarin for 3mo, 6 mo, 1 yr followed by aspirin
Various strategies
No aspirin or warfarin
Lifelong Warfarin
Lifelong aspirin
Warfarin for 3mo, 6 mo, 1 yr followed by aspirin
3-6 mo aspirin