Abstract 16749: Estimation of Stroke Volume and Aortic Valve Area in Patients With Aortic Stenosis: A Comparison of Doppler-Echocardiography and Cardiac Magnetic Resonance
BACKGROUND: In patients with aortic stenosis (AS), accurate measurement of LV stroke volume (SV) is essential for the calculation of aortic valve area (AVA), one of the main parameters used for the assessment of AS severity. Furthermore, a low flow state (i.e. SV index ≤ 35 ml/m2) has been shown to be a powerful predictor of adverse outcome in AS. Underestimation of SV may lead to the erroneous conclusion regarding AS severity and/or low-flow state. The objective of this study was to examine the agreement between SV determined by several Doppler-echocardiographic (DE) and cardiac magnetic resonance (CMR) methods.
METHODS: 111 patients with AS, prospectively recruited in the PROGRESSA study (NCT01679431), underwent DE and CMR. SV was estimated by DE from the product of LV outflow tract (LVOT) velocity-time integral and cross sectional area measured: i) at 5 to 10 mm below the aortic valve (=SVe1) as recommended in the ASE-EAE guidelines and ii) at the base of the aortic valve leaflets (SVe2). SV was determined by CMR using: i) phase contrast mapping acquired in the aorta at 10 mm above the aortic valve annulus (SVc1; reference method); ii) the volumetric method: difference between LV end-diastolic and end-systolic volumes (=SVc2). The AVA was calculated with each of these 4 SVs using the continuity equation method. Comparisons of SVs or AVAs were performed with paired t test and Bland Altman plot.
RESULTS: Compared to the SV measured by phase contrast CMR (referent; SVc1: 82±18 ml), SVe2 showed good agreement (81±14 ml; p=0.33; bias=-1.6±17.8 ml), SVc2 was higher (98±21 ml; p<0.0001; bias=+15.5±12.6 ml) and SVe1 was lower (69 ±13 ml; p<0.0001; bias=-13.2±16.7 ml). Similar results were obtained for AVAs: compared to AVAc1 (1.24±0.37 cm2), AVAe2 was similar (1.21±0.31 cm2; p=0.23; bias=-0.03±0.28 cm2), whereas AVAc2 was higher (1.48±0.44; p<0.0001; bias=+0.23±0.20 cm2), and AVAe1 was lower (1.05 ±0.29; p<0.0001; bias=-0.20±0.26 cm2).
CONCLUSION: Our findings suggest that the DE method providing the most accurate measure of SV and thus of AVA is the one using the LVOT diameter measured at the base of the aortic valve leaflets. On the other hand, the method proposed in the 2009 ASE-EAE guidelines underestimates the SV and AVA, whereas, CMR volumetric method overestimates SV.
Author Disclosures: R. Capoulade: None. F. Le Ven: None. J. Garcia: None. L. Tastet: None. A. Dahou: None. J.G. Dumesnil: None. M. Arsenault: None. E. Bedard: None. E. Larose: None. P. Pibarot: None.
- © 2014 by American Heart Association, Inc.