Second trimester cardiac diagnosis: screening standards and outcomes

Area of Science:

• Medical imaging
• Prenatal diagnostics
• Cardiology

Background:

• Second trimester screening for congenital heart defects (CHDs) is typically performed during the 18-20 weeks' anomaly scan.
• While experts in fetal echocardiography achieve high detection rates, these are often not reproducible in lower-risk peripheral settings.
• The majority of CHDs occur in low-risk pregnancies, necessitating widespread screening.

Purpose of the Study:

• To evaluate the effectiveness of current screening protocols for CHDs.
• To identify the challenges in achieving expert-level detection rates in routine screening.
• To propose improvements for prenatal CHD screening in low-risk populations.

Main Methods:

• Review of existing studies on prenatal screening for CHDs.
• Analysis of different screening protocols, including basic (four-chamber view) and extended scans (outflow tract, three-vessel, and laterality views).
• Discussion of the impact of sonographer skill and training on detection rates.

Main Results:

• Extended screening protocols significantly increase sensitivity compared to basic scans.
• Detection rates in peripheral practices often fall short of those achieved by experienced specialists.
• Additional expertise is required to perform and interpret extended views accurately.

Conclusions:

• Standardized protocols are important but vary in sensitivity.
• Enhanced training and collaboration between tertiary and peripheral centers are essential for skill maintenance.
• Implementing robust audit systems is crucial for identifying and addressing screening inaccuracies to improve outcomes.