How is tetralogy of Fallot (TOF) repair managed when a coronary artery crosses the right ventricular outflow tract (RVOT)?

Management of Tetralogy of Fallot Repair with Coronary Artery Crossing RVOT

When a coronary artery crosses the right ventricular outflow tract (RVOT) in tetralogy of Fallot repair, surgical techniques that avoid conduit placement should be prioritized whenever possible, as modern approaches can achieve repair without sacrificing the native pulmonary valve in most cases. 1

Preoperative Assessment

Coronary Anatomy Evaluation

• Mandatory coronary artery delineation before any RVOT intervention 2
• Imaging options include:
  • Echocardiography: Sensitivity 82%, specificity 99% in experienced centers 3
  • Cardiac catheterization with coronary angiography
  • CT coronary angiography: Provides accurate assessment of coronary relationship to RVOT 2

Risk Assessment

• Identify the specific coronary artery crossing the RVOT (most commonly left anterior descending artery arising from right coronary artery) 1
• Evaluate pulmonary valve and annulus size
• Assess branch pulmonary artery anatomy

Surgical Approaches

Primary Repair Options (in order of preference)

1. Annulus-Preserving Techniques (preferred when possible)

   • Pulmonary artery trunk plasty with commissurotomy
   • Infundibulotomy under the abnormal coronary artery
   • Allows preservation of pulmonary valve function 1

2. Modified Transannular Patch

   • When annulus must be opened but coronary can be preserved
   • Vertical incision of pulmonary artery trunk
   • Oblique extension on RV over the anomalous crossing coronary artery 1
   • Leave at least 1 cm of myocardium between suture line and abnormal coronary 4

3. Transatrial-Transpulmonary Approach

   • Excellent long-term outcomes comparable to standard TOF repair 5
   • Avoids ventriculotomy and potential coronary injury
   • 20-year survival of 91% with this approach 5

4. Conduit Placement (last resort)

   • RV-to-PA conduit only when other approaches not feasible
   • Modern surgical techniques have made this largely outdated 1
   • Only 4% of patients with coronary crossing RVOT required conduit in recent series 1

Intraoperative Decision-Making

• Measure RV/LV pressure ratio after repair
• RV/LV pressure ratio >2/3 is a significant risk factor for reoperation 1
• If RVOT obstruction relief is inadequate, consider alternative approach

Postoperative Considerations

Follow-up Protocol

• Annual surveillance with cardiologist experienced in adult congenital heart disease 2
• Regular assessment of:
  • RV function and size
  • Pulmonary regurgitation severity
  • Residual RVOT obstruction
  • Development of arrhythmias

Imaging Surveillance

• Echocardiography at each visit
• Cardiac MRI (gold standard for RV volume/function assessment) 6
• Exercise testing to assess functional capacity and detect arrhythmias 2

Reintervention Indications

• Severe pulmonary regurgitation with symptoms or decreased exercise tolerance 2
• Moderate to severe RV dysfunction or enlargement 2
• Development of symptomatic or sustained arrhythmias 2
• Residual RVOT obstruction with peak gradient >50 mmHg 2

Special Considerations

Reoperation Challenges

• Conduit obstruction may occur with growth in pediatric patients 7
• Adult-sized valved conduits should be considered for adolescents 7
• Transection of main pulmonary artery and mobilization of branch pulmonary arteries may be necessary in complex reoperations 7

Pitfalls to Avoid

• Failure to identify coronary anatomy preoperatively (though absence of preoperative diagnosis has not been associated with worse outcomes in centers using transatrial-transpulmonary approach) 5
• Inappropriate conduit placement when alternative techniques could be used
• Accepting high RV/LV pressure ratios post-repair (associated with increased reintervention risk) 1

The management of TOF with coronary crossing RVOT has evolved significantly, with modern surgical techniques allowing preservation of native pulmonary valve function in most cases and excellent long-term outcomes comparable to standard TOF repair.