Lack of Stroke Volume Determined Flow Reserve Does Not Always Preclude Assessment of Severity of Aortic Stenosis in Low-Flow Low-Gradient State During Dobutamine Echocardiography

The severity of low-flow low-gradient (LFLG) aortic stenosis (AS) during low-dose dobutamine stress echocardiography (LDDSE) is deemed assessable only when stroke volume–determined flow reserve (SVFR) (stroke volume [SV] increase ≥20%) is present. However, due to typically frequently