Regarding “Estimation of Stroke Volume and Aortic Valve Area in Patients with Aortic Stenosis: A Comparison of Echocardiography versus Cardiovascular Magnetic Resonance”

Abstract

Thank you for the opportunity to reply to the letter by Dr. Johnson and his collaborators regarding predictors of systolic anterior motion (SAM) after mitral valve (MV) repair as presented in the recently published ''Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making in the Operating Room.'' 1 OF HEIGHTS AND LENGTHSWe should clarify that the literature refers to leaflet ''length'' as the distance from the mitral annulus to the tip of the leaflet when measured in diastole and leaflet ''height'' as the distance from the mitral annulus to the coaptation point when measured in systole. Lengths are greater than heights, the difference being represented by the residual leaflets that could be dragged into the left ventricular outflow tract (LVOT) to create the anatomic substrate for LVOT obstruction. Maslow et al. 2 have reported that a lower ratio of the anterior leaflet (AL) and posterior leaflet (PL) heights as measured in early systole (AL:PL < 1.3), representing a greater contribution of the PL to coaptation, is an independent risk factor for the development of SAM after MV repair. Nonetheless, in the recent guidelines document we have mistakenly indicated the ratio of lengths rather than heights as a risk factor for SAM. Although it was our intention to indicate the ratio of heights (rather than lengths) as a risk factor, we stand corrected that the correct risk factor for SAM after MV repair is the AL:PL ratio of heights, as measured in early systole.

Echocardiography and EuroSCORE II for the stratification of low-gradient severe aortic stenosis and preserved left ventricular ejection fraction

“…A recent study showed that AVA impacts prognosis only in those with high-gradient AS and preserved LVEF and whether AVA truly adds prognostic information over V max or MPG is not clear in patients with LG SAS [ 34 ]. Although different theories and explanations have been proposed, the inherent variability in calculating SV by echocardiography may have a significant impact on the accuracy in diagnosing true SAS and/or classifying flow state in some patients [ 16 , 35 ]. With the limitations of echocardiography in determining the true severity of AS based on AVA and in the absence of a high pressure gradient, conservative management of LG SAS patients with low EuroSCORE II may be considered as an option in a medium-term with close follow-up.…”

“…Limitations of echocardiography in diagnosis of LG SAS include potential underestimation of stroke volume and AVA. These could potentially lead to misclassification of LG SAS patients [ 35 , 36 ]. However, the technical limitations are not specific to either the low-risk or high-risk groups.…”