VP15.10: Retrograde flow in aortic isthmus in normal and congenital heart defect fetuses by principal component analysis and computational fluid dynamics

Retrograde flow (RF) in the aortic isthmus is frequently observed in fetuses in various hemodynamic states including congenital heart defects (CHD). This study sought to: establish the association between this observation and variables of CHD by fetal echocardiography (FE); and to develop a CFD model to probe the causes and mechanisms underlying this observation. A total of 256 fetuses (gestational age (GA) 26.3 ± 9.8 weeks) with CHD and 1,168 normal ones (GA: 25.8 ± 10.3 weeks) were examined by FE from January, 2011 to May, 2016. The study group was divided into: 1. no RF; 2. end systolic RF; 3. end diastolic RF; 4. systolic RF; 5. diastolic RF and 6. systolic and diastolic RF sub-groups. Using principal component analysis (PCA), the component score coefficient matrix and optional variance percent (OVP) was calculated by PCA and the RF pattern was simulated by CFD with decreased flow volume in fetal aorta model. Component analysis by PCA showed that four types of variables were associated with RF: 1. volume factor, that the extraction sums of squared loadings percent of variance (V%) was 25.7%, cumulative percent (C%) was 25.7%; 2. Resistance factor (V% 19.6% and C% 45.3%); 3. growth factor (V% 14.1% and C% 59.5%); 4. velocity factor (V% 12.5% and C% 72.9%). RF modeling by CFD was feasible and the backward flow occurs when aortic flow was reduced from 100% to 60%, and decreased further as flow was reduced to 40% and 20% at aorta isthmus. CFD based on FE is feasible and demonstrated that both structural defects of CHD and reduced aortic flow are associated with reversed flow in the aortic isthmus. Supporting information can be found in the online version of this abstract Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.