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Truncus arteriosus (TA) is a rare congenital cardiovascular anomaly characterized by a single arterial trunk arising from the heart by means of a single semilunar valve (i.e. truncal valve). Pulmonary arteries originate from the common arterial trunk distal to the coronary arteries and proximal to the first brachiocephalic branch of the aortic arch. TA typically overrides a large outlet ventricular septal defect (VSD). The intracardiac anatomy usually displays situs solitus and atrioventricular (AV) concordance. Prevalence ranges from 0.03 to 0.056 per 1,000 live births. In Europe, the average recorded prevalence is 1/10,000 births (including livebirths, stillbirths, and terminations of pregnancy following prenatal diagnosis). No striking difference in frequency is observed between the sexes, although most series contain more males than females. Neonates with TA present with clinical features of congestive heart failure depending on the extent of the increase in volume of pulmonary blood flow and the presence or absence of truncal valve insufficiency. Symptoms of failure manifest as falls in pulmonary resistance and increases in pulmonary overcirculation occur. Tachypnea, tachycardia, excessive sweating, poor feeding may be the first signs to appear. The etiology of TA remains unknown. In experimental animal models, TA has been linked to abnormal development of cells from the neural crest that are normally located in the outflow region of the developing heart; this is also thought to be an important etiologic factor in some cases of human TA. Prenatal detection of truncus arteriosus by ultrasound is documented. In the last 10 to 15 years there have been clinically significant improvements in treatment with early repair. It is now recommended that TA is repaired in the neonatal period and morbidity and mortality are as low as 5% in selected series. Currently, surgical management consists of complete repair with closure of the VSD. |