Evaluation of cardiac findings using speckle tracking in fetuses with hemoglobin Bart's disease

Ultrasound Obstet Gynecol. 2024 May 6. doi: 10.1002/uog.27676. Online ahead of print.


Objective: Hemoglobin (Hb) Bart's disease is a severe manifestation of alpha thalassemia, resulting in fetal tissue hypoxia and severe anemia. There is limited research available on assessing fetal speckle tracking analysis as a response to fetal anemia caused by Hb Bart's disease and its utility as a sonographic predictor for Hb Bart's disease. This study aimed to assess the diagnostic performance of fetal cardiac parameters derived from speckle tracking echocardiography for distinguishing between affected and unaffected fetuses in pregnancies at risk of Hb Bart's disease during the 17-24 gestational weeks.

Methods: A total of 115 pregnant women at risk for fetal Hb Bart's disease, who underwent either amniocentesis or cordocentesis at Siriraj Hospital, Bangkok Thailand, were included. Speckle tracking analysis was performed on the 4-chamber view (4CV) of the fetal heart, assessing heart size, shape, ventricular contractility, and left ventricular function prior to invasive prenatal testing. Logistic regression analysis determined significant cardiac predictors and calculated the probability of a fetus having Hb Bart's disease.

Results: Among the cohort, 38 fetuses (33%) were diagnosed with Hb Bart's disease, and 9 cases (7.8%) exhibited frank hydropic signs. In comparison to the control group, affected fetuses displayed a notable enlargement of the 4CV and a more globular shape specifically in the right ventricular chamber. Additionally, there were significant differences in the left global and longitudinal contractility between affected and unaffected fetuses. However, at mid-gestation, no significant distinctions were observed in terms of transverse contractility and left ventricular function between the two groups. Based on logistic regression analysis, combined cardiac parameters derived from speckle tracking analysis as a function of head circumference, could differentiate non-hydropic fetuses with Hb Bart's disease from unaffected fetuses, achieving a maximum sensitivity of 100%, specificity of 98.7%, and overall accuracy of 99.06%.

Conclusions: Speckle tracking echocardiography has the potential to accurately identify early fetal heart changes in individuals at risk of developing Bart's anemia during the second trimester. This not only offers a novel predictive marker for Hb Bart's disease but also helps address the question of the underlying mechanisms of heart failure associated with anemia. This article is protected by copyright. All rights reserved.

Keywords: fetal cardiac function; fetal cardiac size and shape; hemoglobin Bart's disease; prediction; second trimester; speckle tracking.