OP09.03: CASSEAL: fetal cardiovascular system sonographic evaluation algorithm - multicentric study on its feasibility for prenatal diagnosis

To evaluate the feasibility of the cardiovascular system sonographic evaluation algorithm (CASSEAL) to study the extended fetal cardiovascular system including the portal, thymic, and supra-aortic areas, in the second trimester of pregnancy (18-22 weeks). A multicentric cross-sectional study was performed on pregnant women (singleton and twin pregnancies) attending for routine US exam 7 centres in Spain (15 examiners) since 2014 to 2016. CASSEAL consists on a sequential acquisition of axial views comprising the following (caudal to cranial): I, portal sinus; II, ductus venosus; III, hepatic veins; IV, four chambers; V, left ventricle outflow tract; VI, right ventricle outflow tract; VII, three vessels and trachea; VIII, thy-box; and IX, subclavian arteries. Feasibility and exploration time were determined. Maternal, fetal, and ultrasound factors affecting both features were evaluated. A total of 1505 cases were assessed. The frequencies of visualisation for each view and use of colour Doppler are shown in table 1. Mean exploration time was 6.43 minutes (SD, 4.8 minutes). Figure 1 shows the CASSEAL 9 axial sonographic views. Factors associated in a lower frequency of visualisation in univariate and multivariate analysis are maternal body index, breech presentation, occiput anterior fetal position and exploration time (p<0.05). CASSEAL feasibility is over 98% visualisation in almost all views with the exception of view VIII-Thy-box which shows the lowest visualisation (88.6%). Clinical application of CASSEAL is useful for systematising the US exploration of fetal cardiovascular structures and, thus, could contribute to the prenatal diagnosis of arterial, venous, and cardiac abnormalities given its wider exploration area.