Understanding the Aortic Isthmus Doppler Profile and Its Changes with Gestational Age Using a Lumped Model of the Fetal Circulation

作者：Garcia Canadilla Patricia^*; Crispi Fatima; Cruz Lemini Monica; Valenzuela Alcaraz Brenda; Rudenick Paula A; Gratacos Eduard; Bijnens Bart H

来源：Fetal Diagnosis and Therapy, 2017, 41(1): 41-50.

DOI：10.1159/000444142

• Aortic isthmus
• Computational model
• Fetal circulation
• Doppler

Objective: The aortic isthmus (Aol) 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 Aol 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 Aol flow profile through gestation were assessed. Results: Our model allows to simulate the Aol 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 Aol 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.

• 出版日期2017