RESUMEN
BACKGROUND: The study objective was to assess the severity, progression rate, and risk factors for aortic root dilatation (ARD) in pediatric tetralogy of Fallot (TOF) and to study its relationship to complications including aortic regurgitation. METHODS AND RESULTS: Seven hundred sixty-eight TOF patients were studied with echocardiography (median age at repair 6.1 months; interquartile range, 4.5-11.3 months) and compared with 304 controls. Five hundred ninety-two (77%) had usual TOF, 41 (5.3%) TOF-type double outlet right ventricle, and 135 (17.6%) TOF with pulmonary atresia. Median follow-up was 3.7 years (interquartile range, 0.5-6.9 years, total follow-up 3002 patients-years). Aortic root dimensions were enlarged at TOF diagnosis and during follow-up. Mean aortic valve annulus Z score at first postoperative echo was 3.3±2.7, associated with TOF type (TOF