Anticoagulation in CHD Algorithm¶

flowchart TD
    A[CHD Patient Requiring<br/>Anticoagulation Assessment] --> B{Indication?}

    B -->|Fontan| C[Fontan Protocol]
    B -->|Mechanical Valve| D[Mechanical Valve Protocol]
    B -->|Bioprosthetic| E[Bioprosthetic Protocol]
    B -->|Systemic to PA Shunt| F[Shunt Protocol]
    B -->|Kawasaki CAA| G[Kawasaki Protocol]
    B -->|AF/Flutter in CHD| H[AF Protocol]

    C --> C1{Fenestration?}
    C1 -->|Yes| C2[Warfarin INR 2.0-3.0<br/>or LMWH]
    C1 -->|No| C3[Options vary by center]
    C3 --> C4[Aspirin alone<br/>OR]
    C3 --> C5[Warfarin INR 2.0-3.0<br/>OR]
    C3 --> C6[DOAC - emerging data]

    D --> D1{Valve Position}
    D1 -->|Mitral| D2[Warfarin INR 2.5-3.5<br/>+ Aspirin 81mg]
    D1 -->|Aortic| D3[Warfarin INR 2.0-3.0<br/>± Aspirin]
    D1 -->|Tricuspid/Pulmonary| D4[Warfarin INR 2.5-3.5]

    E --> E1{Timeframe}
    E1 -->|First 3-6 months| E2[Warfarin INR 2.0-3.0<br/>OR Aspirin]
    E1 -->|After 3-6 months| E3[Aspirin alone<br/>if sinus rhythm]

    F --> F1[Aspirin + Warfarin<br/>OR Aspirin + Clopidogrel<br/>OR Aspirin alone]

    G --> G1{Aneurysm Size}
    G1 -->|No/Small CAA Z<5| G2[Low-dose Aspirin only]
    G1 -->|Medium CAA Z 5-10| G3[Aspirin + Clopidogrel<br/>OR Aspirin + Warfarin]
    G1 -->|Giant CAA Z≥10| G4[Aspirin + Warfarin<br/>+ Clopidogrel]

    H --> H1[Anticoagulation indicated<br/>Warfarin or DOAC<br/>CHA2DS2-VASc may not apply]

    style D2 fill:#ff6b6b
    style G4 fill:#ff6b6b

📋 Text Version (if diagram doesn't render)

**Anticoagulation in CHD by Indication** 1. **Fontan:** - Fenestration? → Warfarin INR 2.0-3.0 or LMWH - No fenestration → Options: Aspirin alone, Warfarin INR 2.0-3.0, or DOAC (emerging) 2. **Mechanical Valve:** - Mitral → Warfarin INR 2.5-3.5 + Aspirin 81mg - Aortic → Warfarin INR 2.0-3.0 ± Aspirin - Tricuspid/Pulmonary → Warfarin INR 2.5-3.5 3. **Bioprosthetic:** First 3-6 months: Warfarin or Aspirin; After: Aspirin alone if sinus rhythm 4. **BT Shunt:** Aspirin ± Warfarin or Clopidogrel 5. **Kawasaki CAA:** - Small (Z<5) → Low-dose ASA only - Medium (Z 5-10) → ASA + Clopidogrel OR ASA + Warfarin - Giant (Z≥10) → ASA + Warfarin + Clopidogrel 6. **AF/Flutter in CHD:** Anticoagulation (Warfarin or DOAC)

Fontan Circulation¶

Thrombosis Risk Factors¶

Sluggish flow in Fontan pathway
Hepatic dysfunction
Atrial arrhythmias
Protein C/S abnormalities common

Anticoagulation Options¶

Strategy	Regimen	Notes
Aspirin alone	3-5 mg/kg/day	Some centers for low-risk
Warfarin	INR 2.0-3.0	Traditional approach
DOAC	Rivaroxaban, apixaban	Emerging data, not FDA approved for this

Fenestrated Fontan¶

Higher stroke risk from paradoxical embolism
Anticoagulation strongly recommended
Warfarin preferred by many

Mechanical Heart Valves¶

Absolute Requirements¶

Lifelong anticoagulation
Warfarin ONLY (DOACs contraindicated)
Add aspirin for mechanical mitral

Position	Target INR
Aortic	2.0-3.0
Mitral	2.5-3.5
Tricuspid	2.5-3.5

Bridging for Procedures¶

High-risk valve: Bridge with heparin/LMWH
Avoid interruption if possible for minor procedures

Kawasaki Disease CAA¶

By Aneurysm Size (2024 AHA)¶

Classification	Z-score	Anticoagulation
No involvement	<2.0	None after acute phase
Dilation only	2.0-2.5	Low-dose ASA 6-8 weeks
Small aneurysm	2.5-5.0	Low-dose ASA until regression
Medium aneurysm	5.0-10	ASA + clopidogrel OR ASA + warfarin
Giant aneurysm	≥10 or ≥8mm	ASA + warfarin (INR 2.0-3.0) + clopidogrel

Systemic to PA Shunts (BT Shunt)¶

Risk¶

Shunt thrombosis = life-threatening (cyanosis, death)
Small shunts at higher risk

Regimen (varies by center)¶

Aspirin (most common)
Aspirin + clopidogrel (some centers)
Heparin drip immediately post-op

Bioprosthetic Valves¶

Early Post-Implant (0-6 months)¶

Anticoagulation or aspirin
Center/surgeon dependent
Risk of valve thrombosis highest early

Long-term¶

If sinus rhythm: Aspirin alone usually sufficient
If AF: Anticoagulation (warfarin or DOAC)

Special Considerations¶

DOACs in CHD¶

Limited data
Contraindicated in mechanical valves
May be reasonable for AF in CHD
Fontan DOAC trials ongoing

Pregnancy¶

Warfarin teratogenic (first trimester especially)
Switch to LMWH for conception and first trimester
Detailed planning required

Monitoring¶

Warfarin: INR monitoring, patient education
DOACs: Renal function
All: Bleeding precautions, drug interactions