Accuracy of routine ultrasonography in screening heart disease prenatally. Gruppo Piemontese for Prenatal Screening of Congenital Heart Disease.

The aim of the present study was to assess the accuracy of the four-chamber view as a screening test for detection of congenital heart disease (CHD) prenatally in a low-risk population. A prospective observational study was conducted in 17 ultrasound units of the Piemonte Region, Italy, in pregnancies with no risk factors for CHD. At each routine scan, from 18 weeks of gestational age, the four-chamber view of the heart was looked for. When an anomaly was suspected, the patients were referred to a specialized unit. Follow-up of the babies until discharge from the hospital was obtained. 11,232 sonograms were performed on 8299 pregnancies. Cardiac malformations were diagnosed in 40 newborns (4.8/1000). Six of them (15 per cent) had been recognized in utero. The sensitivity, specificity, and positive and negative predictive values were 15, 99.9, 50, and 99.6 per cent, respectively. When malformations that are not associated with an abnormal four-chamber view were excluded from the analysis, the sensitivity increased to 35.3 per cent. The sensitivity found in this study is low, but it is probably realistic since it is comparable to that reported in other multicentric studies. This type of study should reflect the state of the art of the method applied in the field. Although the sensitivity is low, it would be nil if the test were not performed. Moreover, it will probably increase with better training of the operators and by extending the examination to the ventriculo-arterial connections.