Severity Scores for Ebstein Anomaly: Credibility and Usefulness of Echocardiographic vs Magnetic Resonance Assessments of the Celermajer Index.

BACKGROUND

The severity score of Ebstein anomaly (EA) that corresponds to clinical status is still under research, with the Celermajer index (Cel-ind) being one of those. The agreement between echocardiographic and cardiac magnetic resonance (CMR) assessment of Cel-ind is not known. We determined the agreement between echocardiography- and CMR-derived Cel-ind and its relationship with heart failure markers.

METHODS

A total of 37 unoperated adults with EA (mean age, 43.0 ± 14.4 years) underwent echocardiography, CMR, and cardiopulmonary tests. For the Cel-ind, end-diastolic areas in echocardiography or end-diastolic volumes in CMR were used according to the following formula: Cel-ind = (right atrium + atrialized right ventricle)/(functional right ventricle + left atrium + left ventricle). On the basis of this assumption, patients were classified as follows: grade 1 = Cel-ind < 0.5, grade 2 = 0.5 to 0.99, grade 3 = 1.0 to 1.49, grade 4 > 1.5. The agreement between echocardiographic and CMR was determined with the intraclass correlation coefficient or Cohen's kappa (<0.2 poor agreement; 0.2-0.4 fair agreement; 0.4-0.6 moderate agreement; 0.6-0.8 good agreement; 0.8-1.0 very good agreement).

RESULTS

The median echoCel-ind was 0.9 (range, 0.4-2.3), and the median cmrCel-ind was 0.7 (range, 0.3-5.3). Grade 1 or 2 was found in 19 patients (51.3%) by echocardiography and in 27 patients (72.9%) by CMR. The agreement between imaging methods was only fair (kappa = 0.39, P = 0.002) for the 4-grade classification and moderate (intra-class correlation coefficient = 0.43; 95% confidence interval, 0.13-0.66) for Cel-ind calculation. Significant correlations between Cel-ind in CMR and cardiopulmonary parameters were found (for peak oxygen uptake: R = -0.35, P = 0.034; for the ventilation/carbon dioxide slope: R = 0.46, P = 0.005). Neither of them correlated with echocardiographic severity score.

CONCLUSIONS

The agreement between echocardiographic and CMR assessment of the Cel-ind is at most moderate; echocardiography usually overestimates, but rarely underestimates, EA severity. Cel-ind by CMR seems to be more valuable, because it is associated with heart failure markers.