Ebstein's anomaly of the tricuspid valve management – the importance of right ventricle assessment
Authors: Klauco F , Kaldararova M , Reptova A , Valkovicova T , Bobocka K , Hlavata T , Simkova I 
Published: October 2022

Abstract

Background
Ebstein's anomaly (EA) is a rare congenital heart disease (CHD) characterized by well known echocardiographic (ECHO) features. The golden standard method for evaluating these patients is cardiac magnetic resonance (CMR) although not easily accessible. The aim of the study was to evaluate the correlation between ECHO and CMR parameters and to determine the optimal parameters for long-term follow-up. Performed was a retrospective cross-section analysis from our registry, which we consider national, as we serve as the only national adult CHD centre.

Material and methods
Of the 48 patients in the EA national registry, 28 non-operated adults (60% male, median age 39 (18–64) years) with performed CMR were included. Analyzed were ECHO and CMR right ventricular (RV) characteristics, NTproBNP and 6-minute walking distance (6MWD). ECHO parameters were evaluated as follows: 1. morphometric [tricuspid valve septal cusp displacement (mm), long-axis RV end-diastolic dimension (RVEDD,mm), long-axis end-diastolic right to left ventricle diameter ratio (RV/LV)] and 2. functional [tricuspid annular plane systolic excursion (TAPSE,mm), RV fractional area change (FAC,%), RV tissue Doppler myocardial velocity (m/s)]. CMR-derived analyzed paramaters were: ejection fraction (EF,%) and end-diastolic volume (EDV,ml) indexed per body surface area (BSA,m2). According to CMR-derived EDV, patients were divided into groups: 1. normal size RV (55–105ml/m2), 2. dilated RV (&gt;105ml/m2) and 3. small RV (&lt;55ml/m2).

Results
For ECHO morphometric measurements, Spearman's correlation (R) showed strong, statistically significant correlation of CMR-derived EDV with ECHO-based RV/LV ratio (R=0.6989, P&lt;0.0001); and moderate, statistically significant correlation with ECHO-based RVEDD (R=0.55, P=0.004); No significant correlations between CMR-derived EF and ECHO parameters were found. CMR-derived EF and EDV were independent of the severity of septal leaflet displacement; CMR-derived EF was shown to be conditional to RV EDV, with mean EF in Groups 1/2/3 as follows: 57%/36.5%/25.8% (P=0.0013). CMR-derived Group 3 (small RV) compared to Groups 1 and 2 exhibited worst 6MWD (mean 416m) and highest NTproBNP (mean 1021ng/l) though without statistical significance.

Conclusions
The assessment of RV in EA seems more critical than the morphology of the tricuspid valve itself. Therefore, as in the context of our results, more emphasis needs to be placed on RV size. In particular, small-capacity RV, as we found, showed strong relation to reduced RV function and some (though not significant) to NTproBNP and 6MWD. CMR-derived EDV and EF are accepted as the gold standard method for RV evaluation. Since we detected significant correlation of CMR with simply gained ECHO parameters (RV/LV ratio and RVEDD), we assume that easily accessible ECHO remains a pertinent method in routine follow-up, able to reflect the complex hemodynamic situation in EA.

Funding Acknowledgement
Type of funding sources: None.