Ebstein valve rotation angle: a novel quantitative index of anatomical severity and higher clinical risk in Ebstein's anomaly

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The study aimed to identify cardiovascular magnetic resonance (CMR) imaging parameters representative of Ebstein's Anomaly (EA) anatomical and clinical severity. Materials and Methods Consecutive CMR of patients with EA referred to our Center, were evaluated retrospectively. Displacement index (DI) was defined as the distance between the septal leaflet hinge point and the atrio-ventricular groove over the body surface area. The Ebstein’s valve rotation angle (EVRA) was quantified by connecting the inferior atrio-ventricular groove and the systolic leaflet closure plane. The Celermajer index was calculated using area (Cel-a) and volumes (Cel-v) as the ratio between the atrialized RV (aRV) plus the right atrium over the sum of the functional RV (fRV) and left chambers. The occurrence of unfavorable outcome was defined as the presence of sustained brady-tachyarrhythmia or New York Heart Association (NYHA) class ≥ II for unoperated patients and the presence of an at least moderate tricuspid regurgitation or a sustained brady-tachyarrhythmia during the post-operative hospital stay for patients undergone surgical correction. Results The study included 45 patients (age 28 +/- 15 years, 64% males). DI, Cel-a, Cel-v and EVRA tend to increase with worsening Carpentier classification (p = 0.002, p =0.02, p = 0.01, p < 0.0001 respectively). EVRA was the only parameter that showed to discriminate patients with unfavorable outcome both in the group of operated (68 ± 13.9° vs 43.5 ± 26.8° p = 0.03) and unoperated patients (58 ± 27° vs 30 ± 27°, p = 0.02). Among the other analyzed parameters, aRV indexed end-diastolic volume (68 ± 45 ml/m2 vs 31 ± 22 ml/m2 , p = 0.03) and anatomical RV (192 ± 81 ml/m2 vs 128 ± 32 ml/m2, p = 0.03) were significantly higher in unoperated patients with unfavorable follow-up, while both fRV/ARV axis (0.52 ± 0.14 vs 0.66 ± 0.2, p = 0.04) and volumes (0.67 ± 0.11 vs p 0.87 ± 0.29, p = 0.03) were significantly lower. fRV indexed-end diastolic volume was significantly lower (110 ± 32 ml/m2 vs 145 ± 31 ml/m2 , p = 0.03) in patients with an unfavorable post-operative stay. The EVRA value that showed to best discriminate patients who had an unfavorable follow-up event was 44.5 °, with a sensitivity of 0.57 (0.37–0.76, 95% CI) and a specificity of 0.88 (0.69–0.96, 95% CI). Conclusions EVRA is an emerging parameter that may help to provide a quantitative assessment of EA anatomical severity and may be integrated in the risk stratification for clinical follow-up and surgical planning.