What are the indications for a Transposition of the Great Arteries (TGA) operation?

Indications for Transposition of the Great Arteries (TGA) Operation

The primary indication for TGA operation is the presence of ventriculoarterial discordance where the aorta arises from the right ventricle and the pulmonary artery from the left ventricle, resulting in parallel rather than serial circulation. 1

Types of TGA Operations and Their Specific Indications

Arterial Switch Operation (ASO/Jatene Procedure)

• Primary indication: D-TGA in neonates, ideally performed within the first 2 weeks of life 1
• Currently the gold standard treatment for D-TGA with 90% of patients reaching adulthood 1
• Involves transection and switching of the great arteries with coronary artery transfer

Atrial Switch Operations (Mustard or Senning)

• Historical procedures, no longer preferred as first-line treatment
• Currently indicated only in specific circumstances:
  • When ASO is contraindicated
  • As part of double-switch procedures for certain complex cases

Indications for Reoperation After ASO

1. Right Ventricular Outflow Tract (RVOT) Obstruction

   • RVOT gradient >50 mmHg or RV/LV pressure ratio >0.7 not amenable to percutaneous treatment 2
   • Lesser degrees of obstruction if pregnancy is planned 2
   • Most common cause for reoperation after ASO 1, 3

2. Coronary Artery Complications

   • Coronary artery abnormality with myocardial ischemia not amenable to percutaneous intervention 2
   • Coronary ostial stenosis requiring coronary artery bypass graft or ostial arterioplasty 2

3. Neoaortic Valve/Root Issues

   • Severe neoaortic valve regurgitation 2
   • Severe neoaortic root dilatation (>55 mm) 2

4. Other Indications

   • Significant branch pulmonary artery stenosis 3
   • Mitral valve malformation requiring intervention 3
   • Tracheo-bronchial compression 3

Indications for Intervention After Atrial Switch (Mustard/Senning)

1. Systemic AV Valve Issues

   • Moderate to severe systemic (tricuspid) AV valve regurgitation without significant ventricular dysfunction (RVEF ≥45%) 2

2. Baffle Complications

   • Baffle leak with left-to-right shunt >1.5:1 2
   • Right-to-left shunt with arterial desaturation at rest or with exercise 2
   • Superior vena cava or inferior vena cava obstruction not amenable to percutaneous treatment 2
   • Pulmonary venous pathway obstruction not amenable to percutaneous intervention 2

3. Subpulmonary Stenosis

   • Symptomatic severe subpulmonary stenosis 2

Diagnostic Evaluation Prior to Intervention

• Cardiac MRI: Essential for assessing ventricular function, baffle patency, and great vessel relationships 2
• Echocardiography: First-line imaging for anatomic and hemodynamic assessment 2
• Coronary Evaluation: Anatomic evaluation of coronary artery patency (catheter angiography, CT or MR angiography) is reasonable in asymptomatic adults with d-TGA after arterial switch 2
• Physiological Tests: Myocardial perfusion tests for assessing symptoms suggestive of myocardial ischemia 2

Follow-up Recommendations

• Regular follow-up with ACHD cardiologist: every 12-24 months for stable patients, more frequently for those with complications 2
• Imaging surveillance with echocardiography and/or CMR to monitor for development of complications 2
• Exercise testing to evaluate functional capacity and unmask potential complications 2

Important Considerations

• Surgical interventions should be performed by surgeons with expertise in congenital heart disease 2
• Coronary revascularization should be planned collaboratively between surgeons/interventional cardiologists with expertise in revascularization and ACHD providers 2
• Lifelong specialized care at adult congenital heart disease centers is essential for all TGA patients 1

TGA operations have evolved significantly over time, with the arterial switch operation now being the standard of care for most patients with excellent early and midterm outcomes 4, 5. However, vigilant monitoring for late complications is essential to ensure optimal long-term outcomes.