In rheumatic mitral stenosis. functional left atrial remodelling, more than structural remodelling, correlates with the functional orifice area
Authors: Abdelgawad H , Dufatanye D D , Shehata M S , Waheed I W , Hesham N H , Rizk J R , Abayazeed R A , Dawood M D , Abdel-Hay M A , Zaki A Z 
Published: June 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
In developing countries, rheumatic mitral valve stenosis (MS) is still a problem. Its progression leads to left atrial (LA) damage, which predisposes to atrial fibrillation, thrombus formation, and decompensated heart failure, all of which substantially modify the prognosis and course of the disease. As a result, LA evaluation was shown to be clinically significant in mitral stenosis.Due to the complexity of the LA geometry, currently used techniques like antero-posterior dimension (LAD) and 2D echo derived LA volume (LAV) have several limitations that are corrected by 3D derived LA volumes. Additionally, functional evaluation enables us to evaluate the three physiological functions of the LA: the pump, the conduit, and the reservoir.

Purpose
To assess the LA functions using 2D speckle tracking echocardiography (2D STE) and 3D transthoracic echocardiography (3D TTE) in patients with moderate - severe mitral valve stenosis in comparison to normal healthy subjects

Methods
3D LA volumes and emptying fraction (LA EF) were quantified, and the LA reservoir (LASr), conduit (LAScd) and contraction (LASct) functions using 2D STE were generated using dedicated software.

Results
Fifty patients and 20 healthy controls were studied. Patients’ mean age was 40.2 ±8.8 years, the majority were female 45(81.8%), the mean body surface area was 1.81 ± 0.16 m2. 3D LA maximum (LAVmaxI) and minimum (LAVminI) volumes indexed to BSA were both significantly higher in MS than in the control group, whereas 3D LA EF was significantly lower in MS than in the control group, both with p 0.001.
LA strain reservoir, conduit, and contraction parameters were significantly lower in the mitral stenosis group than in the control group (p =0.001).
All LA assessment parameters (3D LAVmaxI, 3D LAVminI, 3D LAEF, 2D LASr, 2D LAScd, 2D LASct, 2D LAD, 2D LAVI) correlated with each other (p &lt;0.01). However, only 3D LAEF, 2D LASr, 2D LAScd, and 2D LASct showed a correlation with the mitral valve area with a p &lt;0.05, but 3D LAVmaxI and 3D LAVminI did not.
Additionally, in the comparison of moderate and severe mitral stenosis subgroups, 3D LAVmaxI and 3D LAVminI did not show any statistically significant differences between the two groups, although 3D LAEF, 2D LASr, 2D LAScd, and 3D LASct showed significant difference between the two group (p&lt;0.05)

Conclusions
Comprehensive LA assessment is of clinical significance for its predictive and prognostic value in mitral stenosis. In addition, LA function assessment by 3D echocardiography and 2D speckle tracking echocardiography correlate better with mitral stenosis severity than conventional LA size parameters .Accordingly, further research to study the LA functional and structural remodeling by 3D echocardiography and 2D STE in clinical follow up and intervention timing in patients with mitral stenosis is highly recommended.