Approach to residual pulmonary valve dysfunction in adults with repaired tetralogy of Fallot

Residual right ventricular outflow tract and pulmonary valve disease is common in adults with repaired tetralogy of Fallot. Chronic severe pulmonary regurgitation as a result of surgical repair can lead to myriad complications including right ventricular dysfunction, decreased exercise tolerance, right heart failure and symptomatic arrhythmias. The aim of restoring pulmonary valve integrity is to preserve right ventricular size and function with the intent of mitigating the development of symptoms and poor long-term outcomes. Right ventricular size thresholds by cardiac MRI have emerged beyond which reverse right ventricular remodelling after pulmonary valve replacement is less likely. Though pulmonary valve replacement has been shown to improve right ventricular dimensions and symptoms, no consistent improvement in right ventricular ejection fraction or objective measures of exercise capacity have been demonstrated. Furthermore, there are no long-term studies showing that normalisation of right ventricular size results in improved clinical outcomes. New transcatheter techniques of percutaneous pulmonary valve replacement have emerged with good short-term and mid-term outcomes, further adding to the complexity in determining 'when' and 'how' right ventricular outflow tract and pulmonary valve intervention should occur. With improved survival of these patients, the trend towards earlier pulmonary valve replacement at smaller right ventricular size and rapidly evolving transcatheter pulmonary valve techniques, the clinician must balance the goals of preserving right ventricular size and function in an attempt to prevent untoward outcomes with risks of multiple interventions in a patient's lifetime.