Blood flow pattern in the ascending aorta after TAVI and conventional aortic valve replacement: Analysis using 4D-Flow MRI
verfasst von:
Ralf F Trauzeddel, Ulrike Loebe, Alex J Barker, Carmen Gelsinger, Christian Butter, Michael Markl, Jeanette Schulz-Menger, Florian von Knobelsdorff-Brenkenhoff
Transarterial aortic valve implantation (TAVI) is a valid alternative to treat aortic stenosis in patients with high surgical risk. The impact of TAVI on changes in blood flow dynamics in the ascending aorta has not been systematically analyzed. Using temporally resolved, three-dimensional, phase contrast MRI (4D-flow), we studied 3D hemodynamics in the ascending aorta (AAo) after TAVI and compared the results to patients with conventional aortic valve replacement (AVR) as well as healthy controls.
Methods
We enrolled 17 subjects with TAVI (Edwards Sapien, mean age 77±7 years, 9 males), 12 with biological AVR (77±4 years, 8 males), and 9 healthy subjects (55±16 years, 8 males). All underwent 4D-flow MRI at 1.5T (spatial resolution 1.8 x 1.8 x 2.5mm3, temporal resolution 40.8ms). Analysis included quantification of the regional distribution of peak systolic wall shear stress (WSS) and peak systolic flow velocity in the AAo.
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Results
The mean aortic orifice area was 1.9±0.2cm2 (TAVI), 1.4±0.4cm2 (AVR) and 4.0 ±0.8cm2 (Controls) (p<0.001). Mean aortic diameter was 35±3mm, 39±4mm and 31±5mm (p=0.002). Patients with TAVI and AVR showed an asymmetric distribution of systolic WSS in the AAo compared to controls. WSS was significantly elevated anteriorly and right-anteriorly, and reduced posteriorly (Fig. 1). WSS distribution was similar in TAVI and AVR. Both TAVI and AVR exhibited the peak flow velocity along the right-anterior curvature, while this was more central in controls (Fig. 2). Peak velocities did not differ between TAVI and AVR (p=0.550).
Figure 1
Distribution of wall shear stress in the ascending aorta (a=anterior, p=posterior, l=left, r=right).
Figure 2
Distribution of peak blood flow velocity in the ascending aorta (a=anterior, p=posterior, l=left, r=right).
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Conclusions
TAVI and AVR lead to similar alterations in systolic blood flow patterns in the ascending aorta compared to healthy controls.
Funding
None.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Blood flow pattern in the ascending aorta after TAVI and conventional aortic valve replacement: Analysis using 4D-Flow MRI
verfasst von
Ralf F Trauzeddel Ulrike Loebe Alex J Barker Carmen Gelsinger Christian Butter Michael Markl Jeanette Schulz-Menger Florian von Knobelsdorff-Brenkenhoff
