Abstract
Background
A significant proportion of patients with aortic stenosis (AS) have discordance in severity by mean gradient/peak velocity and aortic valve area. Low gradient aortic stenosis (LG-AS) is defined when the aortic valve area is < 1 cm2 consistent with severe AS and mean aortic gradient is < 40 mmHg consistent with non-severe AS. LG-AS represents a diagnostic and therapeutic challenge.
Purpose of Review
To summarize the different categories, diagnosis, management, and prognosis of LG-AS. LG-AS is classified as classical (ejection fraction (EF) < 50%, indexed stroke volume (SVi) < 35 ml/m2), paradoxical (EF > 50%, SVi < 35 ml/m2), pseudo-severe (moderate AS with reduced EF), or normal flow low gradient AS.
Recent Findings
Recent findings emphasize the importance of low-dose dobutamine stress echocardiography and CT calcium score in the assessment of aortic valve. In addition, flow reserve (increase in SV > 50%) can be evaluated during dobutamine stress echocardiography and helps predict perioperative prognosis.
Summary
Patients with LG-AS have better survival with aortic valve replacement (AVR) compared to medical therapy, irrespective of presence or absence of flow reserve. Some recent studies suggest that transcatheter aortic valve replacement (TAVR) may be superior to surgical AVR for patients with a lack of contractile flow reserve or those with paradoxical LG-AS, but further investigation is needed to clarify optimal treatment. The role of TAVR in patients with moderate AS and reduced EF is also under investigation.
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• Sato K, Sankaramangalam K, Kandregula K, Bullen JA, Kapadia SR, Krishnaswamy A, et al. Contemporary outcomes in low-gradient aortic stenosis patients who underwent dobutamine stress echocardiography. J Am Heart Assoc. 2019;8(6):e011168. Findings from this study suggest that in low-gradient AS with reduced ejection fraction, flow reserve or AS severity stratification by dobutamine stress echocardiography was not associated with survival.
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Vidhu Anand, Sunil V. Mankad, and Mackram Eleid declare that they have no conflict of interest.
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Anand, V., Mankad, S.V. & Eleid, M. What Is New in Low Gradient Aortic Stenosis: Surgery, TAVR, or Medical Therapy?. Curr Cardiol Rep 22, 78 (2020). https://doi.org/10.1007/s11886-020-01341-x
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DOI: https://doi.org/10.1007/s11886-020-01341-x