The best cutoff value of middle cerebral artery peak systolic velocity for the diagnosis of fetal homozygous alpha thalassemia-1 disease

Comparing three cardiothoracic ratio measurement techniques and creating multivariable scoring system to predict Bart's hydrops fetalis at 17-22 weeks' gestation

To assess the diagnostic performance of three cardiothoracic (CT) ratio techniques, including diameter, circumference, and area, for predicting hemoglobin (Hb) Bart's disease between 17 and 22 weeks' gestation, and to create a multivariable scoring system using multiple ultrasound markers. Before invasive testing, three CT ratio techniques and other ultrasound markers were obtained in 151 singleton pregnancies at risk of Hb Bart's disease. CT diameter ratio demonstrated the highest sensitivity among the other techniques. Significant predictors included CT diameter ratio > 0.5, middle cerebral artery-peak systolic velocity (MCA-PSV) > 1.5 multiples of the median, and placental thickness > 3 cm. MCA-PSV exhibited the highest sensitivity (97.8%) in predicting affected fetuses. A multivariable scoring achieved excellent sensitivity (100%) and specificity (84.9%) for disease prediction. CT diameter ratio exhibited slightly outperforming the other techniques. Increased MCA-PSV was the most valuable ultrasound marker. Multivariable scoring surpassed single-parameter analysis in predictive capabilities.

Comparison of the Performances of Middle Cerebral Artery Peak Systolic Velocity and Cardiothoracic Diameter Ratio in Predicting Fetal Anemia: Using Fetal Hemoglobin Bart's Disease as a Study Model

OBJECTIVE

The aim of the study was to compare the performances of cardiothoracic diameter ratio (CTR) and middle cerebral artery peak systolic velocity (MCA-PSV) in predicting fetal hemoglobin (Hb) Bart's disease and identify the best CTR cut-off for each gestational period.

METHODS

Pregnancies at risk of fetal Hb Bart's disease (gestational ages of 12-36 weeks) were prospectively recruited to undergo ultrasound examination. The measurements of CTR and MCA-PSV were performed and recorded before invasive diagnosis.

RESULTS

During the study period (2005-2019), a total of 1,717 pregnancies at risk of fetal Hb Bart's disease met the inclusion criteria and were available for analysis, including 329 (19.2%) fetuses with Hb Bart's disease. The mean gestational age at the time of diagnosis was 19.30 ± 5.6 weeks, ranging from 12 to 36 weeks. The overall performance of CTR Z-scores is superior to that of MCA-PSV multiple of median (MoM) values; area under curve of 0.866 versus 0.711, p value <0.001. The diagnostic indices of CTR and MCA-PSV are increased with gestational age. Based on receiver operating characteristic curves of CTR Z-scores, the best cut-off points of CTR at 12-14, 15-17, 18-20, 21-23, and ≥24 weeks are 0.48, 0.49, 0.50, 0.51, and 0.54, respectively. The best cut-off of MCA-PSV is 1.3 MoM, giving the best performance at 21-23 weeks with a sensitivity of 91.8% and specificity of 85.5%.

CONCLUSION

The performance of CTR is much better than MCA-PSV in predicting fetal anemia caused by Hb Bart's disease. Nevertheless, whether this can be reproduced in anemia due to other causes, like isoimmunization, is yet to be explored.

Antenatal screening for haemoglobinopathies: current status, barriers and ethics

Sickle cell disease (SCD) and thalassaemia are genetic disorders that are caused by errors in the genes for haemoglobin and are some of the most common significant genetic disorders in the world, resulting in significant morbidity and mortality. Great disparities exist in the outcome of these conditions between resource- rich and resource-poor nations. Antenatal screening for these disorders aims to provide couples with information about their reproductive risk and enable them to make informed reproductive choices; ultimately reducing the likelihood of children being born with these conditions. This review provides an overview of the current status of antenatal, pre-marital and population screening of SCD and thalassaemia in countries with both high-and low prevalence of these conditions, methods of screening in use, and discusses some of the pitfalls, ethical issues and controversies surrounding antenatal screening. It also discusses outcomes of some screening programmes and recognises the need for the establishment of antenatal screening in areas where their prevalence is highest; namely sub-Saharan Africa and India.