AUTHOR=Sotelo Julio , Franco Pamela , Guala Andrea , Dux-Santoy Lydia , Ruiz-Muñoz Aroa , Evangelista Arturo , Mella Hernan , Mura Joaquín , Hurtado Daniel E. , Rodríguez-Palomares José F. , Uribe Sergio 

TITLE=Fully Three-Dimensional Hemodynamic Characterization of Altered Blood Flow in Bicuspid Aortic Valve Patients With Respect to Aortic Dilatation: A Finite Element Approach

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.885338

DOI=10.3389/fcvm.2022.885338

ISSN=2297-055X

ABSTRACT=Background and Purpose: Prognostic models based on cardiovascular hemodynamic parameters may bring new information for an early assessment of bicuspid aortic valve (BAV) patients, playing a key role in reducing the long-term risk of cardiovascular events. This work quantifies several three-dimensional hemodynamics parameters in different BAV patients and ranks their relationships with aortic diameter. 

Materials and Methods: Using 4D-flow CMR data of 74 BAV patients (49 right-left and 25 right-noncoronary) and 48 healthy volunteers, aortic 3D-maps of seventeen different hemodynamics parameters were quantified along the thoracic aorta. BAV patients were divided in two morphotypes categories, BAV-NonAAoD (where we include 18 non-dilated patients and 7 root-dilated patients), and BAV-AAoD (where we include the 49 patient with dilatation of the ascending aorta). Differences between volunteers and patients were evaluated using MANOVA with Pillai's Trace statistic, Mann-Whitney U-test, ROC-curves and minimum redundancy maximum relevance algorithm. Spearman correlation was used to correlate the dilation with each hemodynamics parameter. 

Results: The flow eccentricity, backward velocity, velocity angle, regurgitation fraction, circumferential wall shear stress, axial vorticity and axial circulation allowed to discriminate between volunteers and BAV patients, even in the absence of dilation. In BAV patients, the diameter presented  an strong correlation (> |+/-0.7|) with forward velocity and velocity angle, and a good correlation (> |+/-0.5|) with regurgitation fraction, wall shear stress, wall shear stress axial and vorticity, also for morphotypes and phenotypes, some of them are correlated with the diameter. The velocity angle proved to be an excellent biomarker in the differentiation between volunteers and BAV patients, BAV morphotypes and BAV phenotypes, with an area under the curve bigger than 0.90, and higher predictor important scores. 

Conclusions: Through the application of a novel 3D quantification method, hemodynamic parameters related to flow direction, such as flow eccentricity, velocity angle, and regurgitation fraction, presented the best relationships with local diameter and effectively differentiated BAV patients from healthy volunteers.