Type 1 truncus arteriosus with posterior sinusal origin of the main pulmonary artery and left coronary artery

Abstract

Introduction: Truncus arteriosus (TA) is an uncommon congenital heart defect with a solitary ventriculo-arterial connection giving rise to the systemic, pulmonary and coronary circulations. We present a unique case of TA with the pulmonary artery originating from the posterior truncal valve sinus. Case Report: A 23-year-old woman was referred for fetal echocardiography at 22 weeks gestation following an abnormal obstetric ultrasound. A common arterial trunk overriding a large ventricular septal defect (VSD) with proximal origin of the main pulmonary artery (MPA) was identified. A diagnosis of TA was made. Amniocentesis demonstrated 22q11 microdeletion. A female infant weighing 2850 g was delivered by normal vaginal delivery at 39 weeks gestation. She was mildly cyanosed with saturations of 85%. Transthoracic echocardiogram confirmed the diagnosis of TA. A solitary trileaflet truncal valve with trivial incompetence was overriding a large VSD. The MPA arose below the sinotubular junction from the posterior truncal sinus, with confluent left and right branch pulmonary arteries. During systole, the pulmonary orifice was partially occluded by the posterior cusp. The left coronary artery (LCA) arose anomalously from the posterior sinus, close to the anterior-posterior commissure. No left anterior descending artery was identified: the LCA coursed along the atrioventricular groove as the circumflex artery. The right coronary artery (RCA) arose from the centre of the anterior sinus. Cardiac CT angiogram confirmed the echocardiographic findings and demonstrated a left anterior descending coronary artery arising from the RCA. Successful surgical repair occurred on day 18 of life. Conclusion: This anatomy is unique given the origin of the pulmonary trunk below the sinotubular junction from the posterior truncal sinus. There are no previous reports of posterior sinus origin of the common pulmonary orifice in Type 1 TA. Early identification of anatomical variants is essential in the successful surgical management of such infants.L6200766582018-01-09 <br />