Fetal Diagnosis of an Aorto-Left Ventricular Tunnel: A Case Report

Abstract

 Aorto-left ventricular tunnel（ALVT）is a rare congenital heart disease characterized by an abnormal communication between the ascending aorta and the left ventricle, bypassing the aortic valve. It is extremely rare, accounting for less than 0.1% of congenital heart diseases, with very few reported cases of prenatal diagnosis; however, prenatal diagnosis is crucial due to the risk of fetal death or sudden death in some cases. A 28-year-old primiparous woman was referred at 36 weeks’ gestation due to fetal cardiomegaly. Fetal ultrasound revealed no signs of hydrops or anemia. The four-chamber view demonstrated significant cardiac enlargement, with a total cardiac dimension of 43.4 mm and a cardiothoracic area ratio of 0.44. Left ventricular systolic function was reduced, with a left ventricular fractional shortening（LVFS）of 0.23. The three-vessel view revealed a dilated aortic diameter, and the three-vessel trachea view showed diastolic aortic regurgitation. Color Doppler imaging of the left ventricular long-axis showed diastolic aortic regurgitation bypassing the aortic valve and flowing into the left ventricle, leading to a prenatal diagnosis of ALVT. A cesarean section was performed at 37 weeks due to the potential need for postnatal emergency surgery. The male neonate, weighing 2,931 grams with Apgar scores of 8 at 1 and 5 minutes, developed hypoxemia requiring endotracheal intubation. Postnatal echocardiography confirmed ALVT, and surgical closure was performed on the same day. Prenatal diagnosis of ALVT enabled timely postnatal intervention. In the fetal diagnosis of ALVT, assessment of the left ventricular outflow tract with color Doppler is crucial.