Prenatal detection of critical cardiac outflow tract anomalies remains suboptimal despite revised obstetrical imaging guidelines.

Background: Fetal echocardiography can accurately diagnose critical congenital heart disease prenatally, but relies on referrals from abnormalities identified on routine obstetrical ultrasounds. Critical congenital heart disease that is frequently missed due to inadequate outflow tract imaging includes anomalies such as truncus arteriosus, double outlet right ventricle, transposition of the great arteries, tetralogy of Fallot, pulmonary stenosis, and aortic stenosis.

Objective: This study evaluated the prenatal detection rate of critical outflow tract anomalies in a single urban pediatric hospital before and after "AIUM Practice Guideline for the Performance of Obstetric Ultrasound Examinations," which incorporated outflow tract imaging.

Design: Infants with outflow tract anomalies who required cardiac catheterization and/or surgical procedure(s) in the first 3 months of life were retrospectively identified. This study evaluated two time periods; pre-guidelines from June 2010 to May 2013 and post-guidelines from January 2015 to June 2016. June 2013-December 2014 was excluded as a theoretical period necessary for obstetrical practices to implement the revised guidelines.

Results: Overall, prenatal diagnosis occurred in 55% of infants with critical outflow tract anomalies; of the three most common defects, prenatal diagnosis occurred in 53% of D-transposition of the great arteries, 63% of tetralogy of Fallot, and 80% of double outlet right ventricle patients. Pre-guidelines, prenatal diagnosis occurred in 52% (52 of 102) infants with critical outflow tract anomalies requiring early cardiac intervention. Post-guidelines, prenatal diagnosis occurred in 61% (33 of 54) infants, not significantly different than the prenatal detection rate pre-guidelines (P = .31).

Conclusions: Despite revised obstetrical guidelines highlighting the importance of outflow tract imaging, referrals and prenatal diagnosis of these types of critical congenital heart disease remain low. Education of obstetrical sonographers and practitioners who perform fetal anatomic screening is vital to increase referrals and prenatal detection of critical outflow tract anomalies.