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Echogenic Intracardiac Foci

Associated With Increased Risk for Fetal Trisomy 21 or Not?

Department of Obstetrics and Gynecology, Washington University School of Medicine, St Louis, Missouri USA.

Address correspondence to Anthony L. Shanks, MD, Department of Obstetrics and Gynecology, Washington University School of Medicine, Campus Box 8064, 660 S Euclid Ave, St Louis, MO 63110 USA. E-mail: shanksa{at}wudosis.wustl.edu

Objective. The purpose of this study was to evaluate the impact of an echogenic intracardiac focus (EIF) on the risk for fetal trisomy 21 (T21) in populations with differing prevalence of T21. Methods. A retrospective cohort study of pregnancies presenting to our prenatal ultrasound units over 16 years (1990–2006) was conducted. Contingency table analysis of the presence of an EIF and diagnosis of fetal T21 was performed. The groups analyzed included the following: (1) all fetuses with EIF plus other sonographic markers, (2) EIF as an isolated sonographic marker, (3) those younger than 35 years with an isolated finding of EIF, and (4) a group with an isolated finding of EIF excluding those at increased risk for T21 on serum screening. Results. Echogenic intracardiac foci were found in 2223 of 62,111 pregnancies (3.6%), and T21 was diagnosed in 218 pregnancies (0.4%). The presence of an EIF along with other markers was associated with a statistically significant risk for T21 (positive likelihood ratio [LR], 4.4; 95% confidence interval [CI], 3.2–6.0; P < .05). An isolated EIF was not associated with a statistically significant increased risk for T21 in patients younger than 35 years (positive LR, 1.7; 95%, CI 0.7–4.1) and those without abnormal serum screening results for aneuploidy (positive LR, 1.6; 95% CI, 0.8–3.1). Conclusions. The finding of an isolated EIF on prenatal sonography does not significantly increase the risk for fetal T21 in populations not otherwise at an increased risk for the disorder. An isolated EIF should be considered an incidental finding in patients younger than 35 years and in those without abnormal serum aneuploidy screening results.

Key Words: Down syndrome • echogenic intra-cardiac focus • fetal trisomy 21 • prenatal diagnosis • sonography

Abbreviations: CI, confidence interval • EIF, echogenic intracardiac focus • LR, likelihood ratio • NPV, negative predictive value • PPV, positive predictive value • T21, trisomy 21