Prognostic Role of Left Atrial Reservoir Strain for Risk Stratification in Aortic Stenosis: A Systematic Review

Figures

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  Figure 1. Overview of the literature search and study selection process.

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  Figure 2. Representative Assessment of Left Atrial Reservoir Strain in Moderate and Severe Aortic Stenosis. Panels (A,B) show a case of moderate aortic stenosis, characterized by relatively preserved LASr values (21.6%) and a lower mean transvalvular pressure gradient (MTPG = 23 mmHg). Panels (C,D) depict a case of severe aortic stenosis, with markedly reduced LASr (14.1%) and a higher transvalvular gradient (MTPG = 43 mmHg). Panels (A,C) display speckle-tracking analysis of the left atrium from the apical view, including segmental strain curves and global LASr values. Panels (B,D) show continuous-wave Doppler recordings across the aortic valve used to derive the mean transvalvular pressure gradient. These examples illustrate the progressive impairment of left atrial reservoir function with increasing severity of aortic stenosis. LASr, left atrial reservoir strain; MTPG, mean transaortic pressure gradient.

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  Figure 3. Bar chart illustrating the frequency with which different categories of prognostic variables were reported across the included studies. Left atrial deformation parameters represent the most consistently investigated domain, followed by clinical and comorbidity-related variables. Structural indices, ventricular function parameters, biomarkers, and hemodynamic markers were less frequently evaluated. CCI, Charlson Comorbidity Index; DM, diabetes mellitus; LA, left atrial; LAEI, left atrial expansion index; LAScd, left atrial conduit strain; LASct, left atrial contractile strain; LASr, left atrial reservoir strain; LV, left ventricular; LV-GLS, left ventricular global longitudinal strain; LVEF, left ventricular ejection fraction; NYHA, New York Heart Association.

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  Figure 4. Prognostic Impact of Left Atrial Reservoir Strain Across Studies [24,26,27,29,30,31,33,34,35,37,38,39,40,41,42,43,44]. Bubble plot displaying effect estimates of LASr across individual studies. Two analytical approaches are shown: continuous models (blue), in which LASr was analyzed as a continuous variable, and categorical models based on predefined LASr cut-off values (red). In general, lower LASr values or reduced LASr categories were associated with a higher risk of adverse clinical outcomes. The vertical dashed line represents the null value (HR/OR = 1). Bubble size is proportional to study sample size. Given the heterogeneity in statistical methodology, endpoint definitions, and multivariable adjustment strategies across studies, the figure should be interpreted as a qualitative representation of the overall direction and consistency of prognostic associations rather than as a direct quantitative comparison of effect estimates. HR, hazard ratio; LASr, left atrial reservoir strain; OR, odds ratio.

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  Figure 5. Scatter plot exploring the association between LASr cut-off values and AVA across studies. Each point represents an individual study, with bubble size proportional to sample size. The horizontal dashed line indicates the mean LASr cut-off value, while the regression line illustrates the overall trend between LASr thresholds and disease severity. The figure is intended as an exploratory descriptive representation and should not be interpreted as evidence of a definitive severity-threshold relationship between AVA and LASr. AVA, aortic valve area; LASr, left atrial reservoir strain.

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  Figure 6. Traffic-light plot illustrating the risk of bias across individual studies [24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44] based on the NIH Quality Assessment Tool. Each row represents a single study, while each column corresponds to one of the 14 methodological domains (Q1–Q14). Color coding reflects the level of methodological quality: green indicates low risk of bias (“Yes”), red indicates high risk (“No”), and yellow denotes unclear or insufficient reporting (“NR/NA/CD”). NIH, National Institutes of Health; Q, quality assessment domain; Y, yes; N, no; NR/NA/CD, not reported/not applicable/cannot determine.

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  Figure 7. Bar chart summarizing the distribution of risk of bias ratings across all included studies [24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44] for each NIH assessment domain (Q1–Q14). Bars represent the number of studies classified as “Yes,” “No,” or “NR/NA/CD” for each criterion. NIH, National Institutes of Health; Q, quality assessment domain; Y, yes; N, no; NR/NA/CD, not reported/not applicable/cannot determine.

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  Figure 8. Proposed Practical Algorithm for LASr-Guided Risk Stratification in Aortic Stenosis. AS = aortic stenosis; LASr = left atrial reservoir strain; AVA = aortic valve area; MTPG = mean transvalvular pressure gradient; LVEF = left ventricular ejection fraction; GLS = global longitudinal strain; E/e′ = ratio of early mitral inflow velocity to mitral annular early diastolic velocity; LAVi = left atrial volume index; sPAP = systolic pulmonary artery pressure; BNP = B-type natriuretic peptide; AF = atrial fibrillation; AVR = aortic valve replacement; TAVR = transcatheter aortic valve replacement.