WS06‐03Ultrasound‐detected heart defects associated with aneuploidy

Abstract

In North America second trimester genetic ultrasound is offered to patients at risk for trisomy 21 and other chromosomal abnormalities who decline invasive testing. In most major studies in which the prevalence of ultrasound markers used for genetic ultrasound are reported, congenital heart defects are identified in less than 10% of fetuses. When one considers that over 50% of fetuses with trisomy 21 and 90% of fetuses with trisomies 13 and 18 have structural malformations of the heart, the question should be raised as to why the wide discrepancy in prevalence and detection rate of heart defects in these fetuses. The purpose of this presentation is to review the prevalence of CHD in fetuses with trisomy 21, trisomies 13 and 18, and all fetuses with chromosomal defects that were identified following second trimester amniocentesis. To ascertain the presence or absence of CHD, each fetus underwent a fetal echocardiographic study using real‐time and color Doppler ultrasound at the time of genetic amniocentesis.The results of the study demonstrated the following: The detection rate for trisomy 21 (n = 80) increased from 62% to 91% when examination of the fetal heart was performed. The detection rate for trisomy 18 (n = 30) increased from 84%% to 97% when the cardiovascular system was evaluated. For fetuses with any chromosomal abnormality (n = 103) advanced maternal age were examined, the examination of the heart increased the detection rate from 61% to 85%.Given the above findings, the inclusion of the fetal echocardiographic evaluation of the fetus significantly increased the detection rate for the above three groups of fetuses. If physicians and/or sonographers desire to increase the ultrasound detection rate for chromosomal abnormalities, examination of the fetal cardiovascular system must occur.