What non‑cardiac complications occur after Fontan surgery and what surveillance and treatment strategies are recommended?

Non-Cardiac Complications of Fontan Surgery

All Fontan patients develop multiple non-cardiac complications requiring lifelong multidisciplinary surveillance, with Fontan-associated liver disease (FALD), protein-losing enteropathy (PLE), thromboembolism, and lymphatic dysfunction being the most clinically significant.

Major Non-Cardiac Complications

Fontan-Associated Liver Disease (FALD)

FALD is nearly universal in Fontan patients and may affect over half within 35 years, progressing to cirrhosis and hepatocellular carcinoma (HCC). 112

Surveillance Strategy

• Initiate baseline screening before Fontan surgery, then every 2-3 years in children/adolescents 11
• Clinical assessment by expert hepatologists
• Biochemical evaluation
• Liver Doppler ultrasound with or without liver stiffness measurement (LSM)
• HCC surveillance must begin 10 years after Fontan surgery (earlier if circulatory failure develops) 1
• Abdominal ultrasound every 6 months by experienced personnel
• Cross-sectional contrast-enhanced imaging (CT/MRI) every 1-2 years 1
• Semi-annual alpha-fetoprotein (AFP) monitoring (levels >10 ng/ml suspicious for malignancy) 1

Key Management Points

• Biopsy required for all radiologically suspicious nodules >1 cm 1
• Liver nodules are common (20-48% prevalence) but mostly benign 1
• Hepatic encephalopathy is rare due to preserved liver function even with severe fibrosis 1
• Portal vein thrombosis is uncommon despite high thrombotic risk 1
• Optimizing hemodynamics is the central therapeutic principle 11

Thromboembolism

Long-term antiplatelet therapy is reasonable after Fontan, with escalation to anticoagulation based on specific risk factors. 333

Risk Factors Requiring Enhanced Thromboprophylaxis

• Atriopulmonary type Fontan connection
• Bilateral bidirectional cavopulmonary anastomoses
• Hypoplastic cardiac chambers with flow stasis
• Blind-ended pulmonary artery stump
• History of previous thrombosis
• Protein-losing enteropathy
• Prolonged pleural effusions
• Arrhythmias
• Ventricular dysfunction 333

Surveillance and Treatment

• Periodic transthoracic echocardiography with focused attention to thrombi identification (Class I recommendation) 33
• If thrombosis suspected: confirm with TEE, MRI, CT angiography, nuclear perfusion scan, or venography 33
• Warfarin or LMWH may be reasonable for 3-12 months post-Fontan 33
• Long-term warfarin reasonable for patients with anatomic/hemodynamic risk factors 33

Protein-Losing Enteropathy (PLE)

PLE is refractory to medical treatment in many cases and represents a classical indication for heart transplantation (present in 36% of transplanted patients). 11

• Results from lymphatic dysfunction and elevated central venous pressure
• Can cause ascites through decreased oncotic pressure from hypoalbuminemia 1
• Lymphatic interventions show promising results 11

Plastic Bronchitis (PB)

PB has become a rarer transplant indication (7% currently vs 15% historically) due to successful lymphatic interventions. 114

Additional Non-Cardiac Complications

Renal Dysfunction

• Chronic kidney disease develops from chronic venous congestion 245

Pulmonary Complications 4

• Pulmonary vascular disease
• Sleep-disordered breathing
• Restrictive lung disease

Gastrointestinal

• Chronic venous insufficiency
• Ascites (may require paracentesis; TIPS contraindicated due to heart failure risk) 1

Hematological 4

• Secondary erythrocytosis
• Thromboembolic complications

Endocrine/Metabolic 46

• Glycemic abnormalities
• Thyroid disorders
• Bone health issues

Neurological 45

• Neurocognitive changes
• Stroke risk
• Anoxic encephalopathy
• Cardioembolic events

Reproductive Health 56

• Pregnancy carries significant risk
• Contraception counseling essential
• Sexual dysfunction

Multidisciplinary Care Requirements

All Fontan patients require lifelong specialized care in tertiary centers with access to: 11

• Congenital heart disease specialists
• Hepatology
• Gastroenterology
• Nephrology
• Radiology
• Pathology
• Psychology
• Endocrinology
• Specialized nursing
• Social work

Critical Pitfalls to Avoid

1. Do not delay HCC surveillance—begin exactly 10 years post-Fontan 1
2. Do not use TIPS for refractory ascites—high heart failure risk 1
3. Do not assume liver nodules are benign—biopsy all suspicious lesions >1 cm 1
4. Do not underestimate thrombotic risk—maintain vigilant surveillance and appropriate prophylaxis 333
5. Do not manage these patients in non-specialized centers—complexity demands expert multidisciplinary teams 11