Abstract
Accuracy of aortic regurgitation (AR) quantification by magnetic resonance (MR) imaging in the presence of a transcatheter heart valve (THV) remains to be established. We evaluated the accuracy of cardiac MR velocity mapping for quantification of antegrade flow (AF) and retrograde flow (RF) across a THV and the optimal slice position to use in cardiac MR imaging. In a systematic and fully controlled laboratory ex vivo setting, two THVs (Edwards SAPIEN XT, Medtronic CoreValve) were tested in a porcine model (n = 1) under steady flow conditions. Results showed a high level of accuracy and precision. For both THVs, AF was best measured at left ventricular outflow tract level, and RF at ascending aorta level. At these levels, MR had an excellent repeatability (ICC > 0.99), with a tendency to overestimate (4.6 ± 2.4% to 9.4 ± 7.0%). Quantification of AR by MR velocity mapping in the presence of a THV was accurate, precise, and repeatable in this pilot study, when corrected for the systematic error and when the best MR slice position was used. Confirmation of these results in future clinical studies would be a step forward in increasing the accuracy of the assessment of paravalvular AR severity.
Highlights
Transcatheter aortic valve implantation (TAVI) is a wellaccepted alternative treatment for patients with symptomatic, severe native aortic valve stenosis who are at high risk for surgical aortic valve replacement (SAVR) [1]
This TAVI-related paravalvular aortic regurgitation (AR) is difficult to evaluate by echocardiography, because of acoustic shadowing artifacts originating from the metallic stent frame and the severe calcifications of the native valve that remains in situ
There was no correlation between the flow velocity and intra-test error, since the scatter plot showed a heteroscedastic scatter pattern. In this ex vivo pilot study, we investigated the accuracy of cardiac magnetic resonance (MR) velocity mapping for quantification of post
Summary
Transcatheter aortic valve implantation (TAVI) is a wellaccepted alternative treatment for patients with symptomatic, severe native aortic valve stenosis who are at high risk for surgical aortic valve replacement (SAVR) [1]. With respect to the incidence and severity of postoperative AR after 30 days, TAVI has a significantly higher rate of moderate or severe AR SAVR (4.2% vs 0.4%) [6]. AR after TAVI mainly consists of paravalvular leakage, resulting from incomplete circumferential apposition of the prosthetic stent frame to the surrounding calcified tissue. This TAVI-related paravalvular AR is difficult to evaluate by echocardiography, because of acoustic shadowing artifacts originating from the metallic stent frame and the severe calcifications of the native valve that remains in situ. This method is angiography based and cannot be used at follow-up
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