Objective: Congenital heart diseases (CHD) are the most common congenital anomalies, and most cases occur in the low-risk population. Prenatal ultrasound screening based on visualization of the four-chamber view has had disappointing results in detecting these anomalies thus far. The aim of this study was to evaluate the diagnostic accuracy of ultrasound screening based on the combination of the four-chamber and outflow-tract views.
Methods: We conducted a multicenter prospective observational study in 15 obstetric units in the Piedmont Region, Italy. All operators received specific training. Data were recorded regarding visualization of the four-chamber view and the outflow tracts at each routine scan in pregnancies without any risk factor. When an anomaly was suspected, the patient was sent to the referral center. We obtained the follow-up data of the newborns until discharge from hospital and calculated the diagnostic accuracy of the test.
Results: 9074 ultrasound scans were performed on 7041 women and complete follow-up information was available for 6368 of them. Fifty-eight cases of CHD were observed at birth or postmortem (prevalence 9.1 per thousand); 38 of them were diagnosed in utero. The sensitivity of the test was 65.5%, the specificity 99.7%, the positive predictive value 70.4% and the negative predictive value 99.7%. The sensitivity of the four-chamber view alone was 60.3%.
Conclusions: The sensitivity was significantly higher than that in a similar study performed in 1997 in the same setting. This improvement can be attributed in part to extension of the examination to the outflow-tract view, but also to technological developments and better training of the operators.
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