Prenatal diagnosis of vascular rings and outcome

Background : Vascular rings (VRs) present with varied symptoms and may result in significant morbidity before an accurate diagnosis is made. Prenatal diagnosis may be useful to plan surgery after birth. Objectives : The purpose of the study was to see the feasibility of accurate diagnosis of VR during antenatal ultrasound examination and describe their outcome. Methods : This is a retrospective observational study between January 2014 and December 2019. Vascular rings were diagnosed on the basis of three vessel tracheal view and neck vessels arrangements on fetal echocardiogram. Postnatal evaluation by transthoracic echocardiography and computerized tomography angiogram was performed. Surgical repair was done as per standard indications. Results : A total of 35 cases of fetal VRs (median gestational age: 24 weeks [range: 19-35]) were diagnosed during the study period. There were four dichorionic diamniotic twin gestation pregnancies. The right aortic arch (RAA) with anomalous left subclavian artery (ALSA) was suspected in 31 fetuses, double aortic arch (DAA) in 3, and circumflex aorta in 1. Twenty-six (74%) patients had successful deliveries. One patient had a spontaneous miscarriage, 2 underwent termination, and 6 were lost to follow-up. Postnatal assessment showed RAA with ALSA in 18, DAA in 5, circumflex aorta in 2, and no abnormality in 1. Twenty-two (86%) were operated (RAA with ALSA: 17, DAA: 4, and circumflex aorta: 1) and four were waiting for surgery. Two patients died due to prematurity-related complications. All survivors are symptom free during follow-up (median: 2.24; range: 0.2-5.6 years). Conclusions : Fetal echocardiography enables prenatal diagnosis and planning of postnatal repair of VRs.