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Valve area and cardiac output in aortic stenosis: quantification by magnetic resonance velocity mapping
L Søndergaard1, P Hildebrandt, K Lindvig
1Danish Research Centre of Magnetic Resonance, Hvidovre Hospital, Denmark.
Insights
Magnetic resonance (MR) velocity mapping accurately measures aortic stenosis severity by quantifying valve area and cardiac output. This non-invasive technique shows potential as a clinical tool for assessing aortic stenosis.
Area of Science:
- Cardiovascular Imaging
- Medical Physics
Background:
- Aortic stenosis is a significant cardiovascular condition requiring accurate assessment of severity.
- Current methods for determining valve area and cardiac output have limitations.
Purpose of the Study:
- To evaluate the accuracy of magnetic resonance (MR) velocity mapping in quantifying valve area and cardiac output in patients with aortic stenosis.
- To compare MR measurements with established methods like heart catheterization, Doppler echocardiography, and indicator dilution.
Main Methods:
- Magnetic resonance (MR) velocity mapping was performed on 12 patients with aortic stenosis.
- Measurements were compared with heart catheterization (n=9), Doppler echocardiography, and indicator dilution (n=11).
Main Results:
- MR-derived mean valve area (1.2 cm²) showed good agreement with catheterization (0.9 cm²) and Doppler echocardiography (1.2 cm²).
- MR-quantified cardiac output (4.9 L/min) closely matched indicator dilution (5.0 L/min).
- MR uniquely quantified regurgitant volume simultaneously.
Conclusions:
- Magnetic resonance (MR) velocity mapping is a promising non-invasive tool for assessing aortic stenosis severity.
- MR accurately quantifies both valvular area and cardiac output, key prognostic indicators.
- MR's ability to measure regurgitant volume enhances its clinical utility.
Abstract:
Valve area and cardiac output were determined with magnetic resonance (MR) velocity mapping in 12 patients with aortic stenosis. Heart catheterization, Doppler echocardiography, and indicator dilution were performed for comparison. Left ventricle could be catheterized in only nine patients; in these cases, MR measured a mean valve area of 1.2 cm2 compared with 0.9 cm2 derived from catheterization data, with a mean difference of 0.2 cm2 between the 2 methods. The limits of agreement were [0.0, +0.5] cm2, less in patients with an important degree of concomitant regurgitation. In the whole material, MR measured a mean area of 1.1 cm2 compared with 1.2 cm2 derived from Doppler echocardiography data, with a mean difference of 0.1 cm2 and [-0.5, +0.6] cm2 as limits of agreement. In 11 patients the cardiac output was quantified by MR to a mean of 4.9 L/min and by indicator dilution to 5.0 L/min, with a mean difference of 0.2 L/min, and [-0.6, +0.8] L/min as limits of agreement. In addition, MR offers the major advance of simultaneous quantification of regurgitant volume in cases of concomitant regurgitation. In conclusion, because the two important prognostic determinants in aortic stenosis--the valvular area and the cardiac output--may be quantified, MR has potential to become a clinical tool in assessment of severity in aortic stenosis.