What are the current European guidelines for the surgical management of Tetralogy of Fallot (TOF)?

Current European Guidelines for Surgical Management of Tetralogy of Fallot

Complete surgical repair should be performed in infancy (typically between 3-6 months of age) with VSD closure and RVOT obstruction relief, achieving survival rates exceeding 98% and 30-year survival rates above 90%. 1

Primary Surgical Approach

The definitive repair consists of simultaneous correction of all four anatomic components: 2

• VSD closure using a patch
• Relief of RVOT obstruction
• Pulmonary valve management (preservation when possible)
• Extracardiac conduit placement when necessary

Surgical Technique Options

Two main approaches exist for RVOT reconstruction: 1

• Transannular patch repair: Most commonly used when valve preservation is not feasible, though this invariably results in severe pulmonary regurgitation and subsequent RV volume overload 1

• RV to pulmonary artery conduit: Alternative approach that may also result in pulmonary regurgitation and RV volume overload 1

A combined transatrial-transpulmonary approach can be employed in select patients (approximately 34% of cases) to minimize ventriculotomy and preserve RV function. 3

Timing of Surgical Intervention

The optimal timing algorithm is: 4, 3

• Symptomatic patients <4 kg (hypercyanotic spells, ductal-dependent circulation): Modified Blalock-Taussig shunt followed by complete repair at 6-12 months 4

• Asymptomatic patients <4 kg with threatened pulmonary artery isolation: BTS followed by repair at 6-12 months 4

• All other patients: Complete repair after 6 months of age, ideally between 3-6 months 4, 3, 5

Early complete repair (mean age 5.2 months, mean weight 4.5 kg) yields excellent results with no hospital mortality and minimal late complications. 3

Preoperative Imaging Requirements

Prior to surgery, cardiac MRI is indicated (Class I, Level of Evidence B) to evaluate: 1

• Detailed anatomy including coronary artery anomalies (particularly anomalous left anterior descending artery crossing the RVOT)
• Ventricular function, volumes, and mass
• Valve function
• Hemodynamics including cardiac index, Qp/Qs, and flows to both lungs
• Tissue characterization with late gadolinium enhancement for prognostication

This comprehensive CMR assessment is essential for surgical planning in routine cases when echocardiography does not show primary indication for intervention or increased pressures. 1

Critical Surgical Considerations

Coronary artery anomalies must be identified preoperatively as they fundamentally alter the surgical approach—an anomalous LAD crossing the RVOT necessitates conduit placement rather than transannular patch. 4, 3

The Nakata index (pulmonary artery size) should be assessed, with adequate repair achievable when the index is approximately 160 mm²/m² or greater. 3

Avoidance of hypothermic circulatory arrest is preferred as it reduces morbidity, though this requires adequate patient size (typically >4 kg). 4

Expected Surgical Outcomes

Contemporary surgical results demonstrate: 1, 4, 3

• Hospital mortality: 0-2.1%
• 30-year survival: >90%
• Mean post-repair peak RV/systemic pressure ratio: 0.48
• Reoperation rate after complete repair: 3%
• Mean RVOT gradient: 15 mm Hg

Postoperative Surveillance Requirements

All patients require lifelong annual follow-up with an adult congenital heart disease specialist. 2

Annual evaluation must include: 2

• History and physical examination by ACHD cardiologist
• 12-lead ECG
• Comprehensive echocardiography
• Cardiac MRI for precise RV volume quantification and pulmonary regurgitation assessment

Periodic Holter monitoring should be performed with frequency individualized based on hemodynamics to detect exertional arrhythmias and prevent sudden cardiac death. 2

Common Postoperative Complications

Nearly universal complications include: 1

• Pulmonary regurgitation leading to RV volume overload
• RV systolic and diastolic dysfunction
• LV dysfunction (from ventricular-ventricular interaction)
• Decreased exercise capacity
• Arrhythmias (atrial flutter/fibrillation, ventricular tachycardia)
• Residual or recurrent RVOT obstruction
• Tricuspid regurgitation

Reintervention Indications

Reoperation is indicated for: 2

• Symptomatic patients with severe pulmonary regurgitation
• Asymptomatic patients with severe pulmonary stenosis or pulmonary regurgitation PLUS progressive or severe RV enlargement or dysfunction
• Residual RVOT obstruction with RV/LV pressure ratio >0.7

Pulmonary valve replacement is the most common reintervention, with heterograft or homograft preferred; mechanical PVR should only be used for patients requiring warfarin for other indications. 2

Critical Pitfalls to Avoid

Transannular patch repair inevitably causes severe pulmonary regurgitation—while this is often necessary, valve-sparing techniques should be employed when anatomically feasible to minimize long-term RV volume overload. 1

Inadequate relief of RVOT obstruction leads to persistent RV pressure overload—the target post-repair RV/LV pressure ratio should be <0.5. 3

Delayed recognition of RV dysfunction is common—the severity of pulmonary regurgitation is often underestimated by clinical examination and requires serial CMR imaging for accurate assessment. 6