What are the 10 commandments of Fontan for optimizing patient outcomes and minimizing complications in patients with Fontan (Total Cavopulmonary Connection) circulation?

The 10 Commandments of Fontan Management

The original "Ten Commandments" described by Choussat in 1977 for ideal Fontan candidacy have been substantially revised based on modern evidence, with contemporary guidelines emphasizing that only two factors consistently predict both early and late outcomes: preserved ventricular function and low pulmonary artery pressures. 1

The Core Principles for Fontan Success

1. Preserve Ventricular Function

• Maintain systemic ventricular function as the single most critical determinant of outcome 1
• Preoperatively impaired ventricular function adversely influences both early mortality and long-term survival 1
• Monitor ventricular function serially with echocardiography as the most useful investigation 2
• Consider advanced heart failure consultation for any patient with severely depressed systolic function by qualitative assessment, echocardiography, or cardiac MRI 2

2. Maintain Low Pulmonary Vascular Resistance and Pressures

• Keep mean pulmonary artery pressure ≤15 mmHg and pulmonary vascular resistance low 2
• Elevated pulmonary artery pressures are the second critical factor predicting poor early and late outcomes 1
• The Fontan circulation depends on passive flow from systemic veins to pulmonary arteries without a subpulmonary ventricle 2
• Consider pulmonary vasodilator therapy for elevated pulmonary vascular resistance, though response is variable 2

3. Minimize Atrioventricular Valve Regurgitation

• Ensure no relevant AV valve regurgitation preoperatively 2
• More than moderate systemic AV valve regurgitation, especially when accompanied by moderately depressed systolic function, warrants advanced heart failure consultation 2
• Monitor AV valve function routinely with echocardiography 2
• Surgical intervention indicated for significant systemic AV valve regurgitation 2

4. Ensure Adequate Pulmonary Artery Size

• Adequate pulmonary artery size is essential for successful Fontan completion 2
• Small preoperative pulmonary artery size is an additional risk factor for reintervention 1
• Address branch pulmonary artery stenosis aggressively with catheter-based interventions 2

5. Maintain Normal Sinus Rhythm

• Normal rhythm is a criterion for optimal Fontan candidacy 2
• Atrial arrhythmias are common and increase with follow-up duration 2
• By 10 years post-Fontan, 20% of patients develop supraventricular tachyarrhythmias 2
• Consider radiofrequency ablation for supraventricular arrhythmias and AV sequential pacing for sinus node dysfunction 2
• Significant electrophysiologic abnormalities including recurrent arrhythmias despite therapy warrant advanced heart failure consultation 2

6. Prevent and Manage Fontan Pathway Obstruction

• Obstruction in the Fontan connection contributes to late failure 2
• Use total cavopulmonary connection (TCPC) with either intracardiac or extracardiac conduit rather than atriopulmonary connection 2
• Monitor for obstruction with echocardiography/TEE and cardiac MRI 2
• Intervene promptly for Fontan pathway or branch pulmonary artery stenosis 2
• Consider conversion to TCPC or transplant in failing Fontan with atriopulmonary connection 2

7. Implement Rigorous Surveillance and Follow-Up

• Require at least yearly review with echocardiography, ECG, Holter monitoring, exercise testing, and blood testing 2
• All Fontan patients require Level 1 follow-up care 2
• Perform routine transesophageal echocardiography every 2 years or if arrhythmia present to assess for thrombus in atrium 2
• Cardiac MRI is required at least once in adult age and further on indication 2
• Monitor for protein-losing enteropathy with blood/stool testing for albumin and α1-antitrypsin 2

8. Manage Chronic Venous Hypertension and Fluid Overload

• The Fontan circulation results in chronic systemic venous hypertension affecting multiple organ systems 2
• Consider advanced heart failure consultation for symptomatic chronic fluid overload persisting despite new or increasing diuretic therapy 2
• Recurrent or refractory pleural effusions or ascites occurring outside the perioperative period warrant advanced heart failure consultation 2
• Prolonged chest tube drainage (>14 or >30 days) postoperatively is associated with development of protein-losing enteropathy and decreased survival 2
• Protein-losing enteropathy has <50% 5-year survival and requires aggressive management 2

9. Provide Endocarditis Prophylaxis

• Endocarditis prophylaxis is indicated in all Fontan patients 2
• This is non-negotiable regardless of Fontan type or clinical status 2

10. Restrict Physical Activity Appropriately

• Limit to recreational sports only on a symptom-limited level 2
• Patients have substantially reduced exercise capacity even when asymptomatic 2
• Decreasing exercise tolerance by patient report or sequential formal testing warrants advanced heart failure consultation 2
• Monitor exercise capacity with routine exercise testing 2

Critical Caveats

The ventricular morphology (left vs. right), surgical technique (TCPC vs. APC), and fenestration do not appear to influence early or late outcome 1. This contradicts older assumptions and emphasizes focusing on the two core hemodynamic principles: ventricular function and pulmonary artery pressures.

Even in the best Fontan patients, premature decline in cardiovascular performance with reduced survival is inevitable 2. Actuarial survival is 90% at 5 years, 86% at 10 years, and 82% at 15 years 1.

Pregnancy is possible only in perfectly selected patients with proper care, but is contraindicated in failing Fontan, with severely reduced pulmonary blood flow, or if oxygen saturation is <85% 2. Avoid estrogen-containing contraceptives if ejection fraction <40%, residual shunt present, or spontaneous contrast in right atrium 2.