The Total Right/Left-Volume Index: A New and Simplified Cardiac Magnetic Resonance Measure to Evaluate the Severity of Ebstein Anomaly of the Tricuspid Valve

Abstract

Background— The classification of clinical severity of Ebstein anomaly still remains a challenge. The aim of this study was to focus on the interaction of the pathologically altered right heart with the anatomically—supposedly—normal left heart and to derive from cardiac magnetic resonance (CMR) a simple imaging measure for the clinical severity of Ebstein anomaly. Methods and Results— Twenty-five patients at a mean age of 26±14 years with unrepaired Ebstein anomaly were examined in a prospective study. Disease severity was classified using CMR volumes and functional measurements in comparison with heart failure markers from clinical data, ECG, laboratory and cardiopulmonary exercise testing, and echocardiography. All examinations were completed within 24 hours. A total right/left-volume index was defined from end-diastolic volume measurements in CMR: total right/left-volume index=(RA+aRV+fRV)/(LA+LV). Mean total right/left-volume index was 2.6±1.7 (normal values: 1.1±0.1). This new total right/left-volume index correlated with almost all clinically used biomarkers of heart failure: brain natriuretic peptide ( r =0.691; P =0.0003), QRS ( r =0.432; P =0.039), peak oxygen consumption/kg ( r =−0.479; P =0.024), ventilatory response to carbon dioxide production at anaerobic threshold ( r =0.426; P =0.048), the severity of tricuspid regurgitation ( r =0.692; P =0.009), tricuspid valve offset ( r =0.583; P =0.004), and tricuspid annular plane systolic excursion ( r =0.554; P =0.006). Previously described severity indices ([RA+aRV]/[fRV+LA+LV]) and fRV/LV end-diastolic volume corresponded only to some parameters. Conclusions— In patients with Ebstein anomaly, the easily acquired index of right-sided to left-sided heart volumes from CMR correlated well with established heart failure markers. Our data suggest that the total right/left-volume index should be used as a new and simplified CMR measure, allowing more accurate assessment of disease severity than previously described scoring systems.

Cardiac MRI right ventricle / left ventricle (RV/LV) volume ratio improves detection of RV enlargement

“…The RV/LV volume ratio has also been used in MRI to evaluate the severity of tricuspid regurgitation and RV dilation in patients with repaired tetralogy of Fallot . The total right/left volume ratio, which also includes the atrial volumes, has been applied for the evaluation of Ebstein's anomaly using MRI . However, we developed the "normal" range of the volume ratio in MRI and to show that the addition of this ratio can detect RV dilation in situations when RVEDVi could not.…”

Clinical aspects of myocardial fibrosis in adults with Ebstein’s anomaly

“…It was labeled cmr-Cel and calculated as the ratio of the summed volumes of RA and aRV to that of the summed volumes of fRV, LV and LA in a 4-chamber view (Fig. 1a) [16, 17]. …”

Emerging Biomarkers of Congenital Heart Diseases and Disorders

“…Flow cytometry [44], cardiac magnetic resonance [45], and echocardiographic are is used as diagnostic tool for finding defects in both the right and the left heart. Echocardiographic is also used to detect pediatric PAH that can be correlated both at presentation and during the course of the disease [46].…”

“…Serum levels of soluble ICAM-1 can provide confirmation about pulmonary artery hypertension in children [36]. Similarly, total right/left-volume index should be used as a new and simplified CMR measure, allowing more accurate assessment of disease severity [44]. Echocardiography and Fontan surgery are used to assess the systemic right ventricle problems in patients with repaired tetralogy of Fallot.…”