- Poster presentation
- Open Access
COVA (cardiac output valve area): a reliable method for determining aortic transvalvular pressure gradients that does not use phase contrast imaging
https://doi.org/10.1186/1532-429X-16-S1-P247
© Patel et al.; licensee BioMed Central Ltd. 2014
- Published: 16 January 2014
Keywords
- Aortic Valve
- Aortic Stenosis
- Mitral Regurgitation
- Regurgitant Volume
- Transvalvular Gradient
Background
Echocardiography is often used to quantify the transvalvular pressure gradient in patients with aortic stenosis. Velocity-encoded MRI is alternative method for quantifying the aortic transvalvular pressure gradient. However, the acquisition of additional phase-contrast images is time consuming and the analysis can be technically difficult. We report on the results from a new method, Cardiac Output Valve Area (COVA), for quantifying the aortic transvalvular gradient that does not rely on phase contrast images. Instead the instantaneous pressure gradient is computed from the cardiac output (based on the frame-by-frame changes in left ventricular systolic volume) and valve area. The purpose of this study is to compare the results from all three methods.
Methods
This retrospective study is comprised of 102 consecutive patients who were referred for cardiac MRI and had aortic stenosis (72 ± 11 yrs, 64% male). Exclusion criteria included an irregular cardiac rhythm, a prosthetic aortic valve, or more than minimal mitral regurgitation (regurgitant volume > 10 ml). COVA mean and peak pressure gradients were determined using SuiteHeart software (research version, Neosoft, Pewaukee, WI). For inputs, the software required multiphase segmentation of the left ventricular endocardium and planimetry of the aortic valve. The results are compared to those obtained from velocity-encoded MRI (using the modified Bernoulli equations: peak pressure gradient = 4*v2, mean pressure gradient = 2.4*v2), and the clinical results from Doppler echocardiography (n = 24). To assess interobserver variability of the COVA method, a subset of 20 patients were analyzed by 2 blinded readers.
Results
Pearson's correlation comparing the peak pressure calculated using the COVA method to velocity encoded MRI and Doppler Echocardiography.
Conclusions
The aortic transvalvular pressure gradient as assessed by COVA correlates well with other accepted measures for assessing AS severity such as velocity encoded MRI and echocardiography. This method does not require the acquisition or analysis of phase-contrast images. In principle, it can be applied to other modalities such as cardiac CT.
Funding
None.
Authors’ Affiliations
Copyright
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/2.0), 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.