Quantitative assessment of disease severity in Ebstein’s Anomaly by cardiovascular magnetic resonance imaging: from bench to bedside

Background: Ebstein’s Anomaly (EA) exhibits significant anatomical and clinical heterogeneity, warranting a systematic approach to risk stratification. While the Carpentier classification (CC) is commonly employed for qualitative disease assessment, there is increasing interest in quantitative imaging parameters, to guide personalized monitoring strategies and therapeutic interventions. Aims: This study aimed to: 1) evaluate the association between cardiovascular magnetic resonance (CMR) parameters, CC, and symptoms of clinical decompensation; 2) determine whether CMR-derived markers may predict the need for bidirectional cavo-pulmonary anastomosis (BCPA), in-hospital hemodynamic instability, and significant right ventricular (RV) dysfunction following tricuspid valve surgery. Methods: This retrospective study evaluated consecutive patients diagnosed with EA undergoing 1.5 Tesla CMR at a tertiary care centre. CC and quantitative indices were derived from steady-state free precession sequences. Results: In a total population of 60 patients (53% male, median age 22 years), CMR parameters most strongly associated (p<0.001) with CC included indexed displacement of the septal (SLDi) and inferior (ILDi) leaflets, Ebstein’s valve rotation angle, functional RV ejection fraction, indexed atrialized RV end-diastolic volume, and the atrialized or functional RV-to-anatomical RV ratio. Decreasing left ventricular ejection fraction (OR 0.85, 95%CI 0.75-0.97, p=0.01) and increasing ILDi (OR 1.05, 95%CI 1.00-1.10, p=0.04) emerged as the most prominent variables associated with symptoms of clinical decompensation. Additionally, ILDi was significantly linked to the need for BCPA (OR 1.15, 95%CI 1.03-1.28, p=0.01), in-hospital hemodynamic instability (OR 1.09, 95%CI 1.01-1.18, p=0.02) and significant RV dysfunction at discharge (OR 1.08, 95%CI 1.01-1.17, p=0.03). Conclusions: Several quantitative CMR indices proved to be effective in distinguishing between Carpentier classes and they may be valuable in an integrated CMR-based approach to assess EA severity. Among these, ILDi may serve as a useful metric in guiding surgical decision-making, particularly regarding the addition of BCPA, as it reflects both the extent of TV abnormality and RV atrialization.