Indications for Pulmonary Valve Replacement in Repaired Tetralogy of Fallot

Abstract

Until Blalock and Taussig developed the first palliative systemic-to-pulmonary shunt operation in 1945,1 tetralogy of Fallot (TOF) was a nearly uniformly lethal congenital cardiac anomaly. In the 5 decades since Lillehei and his colleagues at the University of Minnesota reported the first successful intracardiac repair in 1955,2 early mortality has decreased markedly from 50% to <2%.2–4 In the modern surgical era, most infants with TOF survive the initial surgical repair and reach adulthood. More recently, the excellent results in the pediatric age group have led the field to shift its attention to late sequelae of repaired TOF in the rapidly growing population of adult patients, including the increasing rates of morbidity and mortality. Article see p 1861 Despite many advances in surgical repair during the past 6 decades, the majority of TOF patients continue to experience residual hemodynamic and electrophysiological abnormalities.5,6 To effectively relieve the obstructed right ventricular outflow tract (RVOT), the surgeon must often disrupt the integrity of the pulmonary valve, which results in pulmonary regurgitation. The ensuing chronic right ventricular (RV) volume overload and akinesis or dyskinesis of the RVOT wall, along with conduction delay from the nearly universal right bundle-branch block, initiate a cascade of pathophysiological abnormalities that lead to RV dilatation and ultimately dysfunction.7 Left ventricular dysfunction, arrhythmias, exercise intolerance, heart failure symptoms, and death may follow.8 Residual intracardiac shunts, tricuspid regurgitation, RVOT or pulmonary artery stenosis, impaired diastolic properties, atrial enlargement, RV hypertension, intraventricular and interventricular dyssynchrony, and diffuse myocardial fibrosis are some of the factors that might accelerate the adverse cardiac remodeling and lead to worse clinical outcomes. Indeed, the adverse remodeling that leads to electromechanical cardiomyopathy manifests in increasing rates of morbidity and mortality beginning during the third decade of life.9 Pulmonary …