Understanding the aortic isthmus Doppler profile and its changes with gestational age using a lumped model of the fetal circulation

Objective: The aortic isthmus (AoI) blood flow has a characteristic shape with a small end-systolic notch observed during the third trimester of pregnancy. However, what causes the appearance of this notch is not fully understood. We used a lumped model of the fetal circulation to study the possible...

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Bibliographic Details
Authors: Garcia Canadilla, Patricia, Crispi Brillas, Fàtima, Cruz-Lemini, Mónica, Valenzuela Alcaraz, Brenda, Rudenick, Paula A., Gratacós Solsona, Eduard, Bijnens, Bart
Format: article
Status:Versión aceptada para publicación
Publication Date:2017
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10230/36986
Online Access:http://hdl.handle.net/10230/36986
http://dx.doi.org/10.1159/000444142
Access Level:Open access
Keyword:Computational model
Aortic isthmus
Fetal circulation
Doppler
Description
Summary:Objective: The aortic isthmus (AoI) blood flow has a characteristic shape with a small end-systolic notch observed during the third trimester of pregnancy. However, what causes the appearance of this notch is not fully understood. We used a lumped model of the fetal circulation to study the possible factors causing the end-systolic notch and the changes of AoI flow through gestation. Methods: A validation of the model was performed by fitting patient-specific data from two normal fetuses. Then, different parametric analyses were performed to evaluate the major determinants of the appearance of the end-systolic notch. The changes in the AoI flow profile through gestation were assessed. Results: Our model allows to simulate the AoI waveform. The delay in the onset of ejection together with the longer ejection duration of the right ventricle are the most relevant factors in the origin of the notch. It appears around 25 weeks of gestation and becomes more pronounced with advancing gestation. Discussion: We demonstrated that the end-systolic notch on the AoI flow occurs mainly as a result of a delayed and longer ejection of the right ventricle. Our findings improve the understanding of hemodynamic changes in the fetal circulation and the interpretation of clinical imaging.