Assessment of aortic stenosis severity by rest CMR correlates well with stress echocardiography in the setting of low left ventricular flow states
© Chahal et al.; licensee BioMed Central Ltd. 2014
Published: 16 January 2014
Identifying the high-risk subset of patients with severe aortic stenosis (AS) and low transvalvular pressure gradient due to significant left ventricular (LV) impairment has relied on the assessment of the haemodynamic changes in response to flow normalization using pharmacological stress. Although cardiovascular magnetic resonance (CMR) aortic valve area (AVA) derived from planimetry has shown good correlation with rest echocardiography (RE) assessment , there is scant data on the correlation between rest CMR and stress echo (SE) for measurement of AVA in this cohort of patients.
A total of 46 patients who underwent CMR and both RE and SE were retrospectively studied. Stress echo was clinically indicated in patients with suspected low-flow, low-gradient AS with preserved or impaired LV EF. CMR AVA was determined using planimetry, from the continuity equation during RE and SE. Cardiac index was derived from a through plane flow mapping sequence at the level of the sinotubular junction. Statistical analysis was performed using paired Student's t-test (SPSS version 21).
Aortic valve area stratified by ejection fraction
Rest Echo EF < 40% (n = 20)
Rest Echo EF > 40% (n = 26)
0.94 cm2 **
0.91 cm2 †
Aortic valve area stratified by cardiac index
CMR C.I. < 2.5 L/min (n = 28)
CMR C.I. > 2.5 L/min (n = 18)
0.96 cm2 *
0.87 cm2 **
0.94 cm2 †
0.91 cm2 ‡
In patients with reduced flow rate, RE may over diagnose AS severity. There is a good correlation between rest CMR and SE in this group, suggesting that CMR planimetry of the aortic valve is adequate in these patients and the need for normalization of flow with pharmacological stress may not always be clinically necessary.
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