Effective RV ejection fraction by CMR: a new index of RV function in patients with severe TR

Abstract Background Right ventricle (RV) dysfunction represent an formal indication for intervention in patients with significant tricuspid regurgitation (TR). RV ejection fraction (RVEF) by Cardiac Magnetic Resonance (CMR) is considered the gold standard of RV function; however it is influenced by changes of preload conditions and may remain unaffected until late stages in severe TR. Effective RV ejection fraction (eRVEF) is corrected by the amount of TR and may reflect an earlier parameter of RV dysfunction. Purpose To compare the prognostic impact of both indices of RV function: RVEF and eRVEF in a multicentre cohort of patients with severe TR. Methods Patients with at least severe TR assessed by 2D echocardiography with a contemporary cardiac magnetic resonance (CMR) study were included in this study. In addition to conventional parameters of biventricular volume and function, eRVEF was assessed in all patients. eRVEF was calculated according to the formula: eRVEF=net pulmonary forwardflow/RV− EDV (figure). A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined. Results 271 patients with severe TR recruited from 5 tertiary care hospitals were included in this study (age 71 ± 11 years, 67% female, 83% NYHA I or II). Regarding the etiology, 10% were primary TR, 1% CIED-related TR, 46 % atrial secondary TR and 43% ventricular secondary TR. After a median follow-up of 27 months (IQR: 10-53 months), 41% of the patients (n=112) experienced the combined endpoint (n=97 were admitted due to HF, n=49 died). After adjusting for age, NYHA class, comorbidities, type of TR and LVEF in multivariate Cox proportional models, both RVEF and eRVEF were independently associated with all-cause mortality and heart failure (adj HR for RVEF HR per 1%=0.96 [0.94-0.98], p<0.001 and for eRVEF per 1%=0.98 [0.96-0.99], p<0.001). A value of eRVEF of ≤37% were associated with impaired prognosis (figure). eRVEF identified higher rates of RV dysfunction compared to RVEF (49% vs 38%, p<0.001). eRVEF was superior to RVEF to predict outcomes (higher AUC 0.70 [0.63-0.76] vs 0.66 [0.59-0.73, p<0.001; Δ C-statistic 0.139 [0.040-0.237], p=0.05). Conclusion RV function is crucial for determining optimal timing for TR intervention. eRVEF is corrected by the amount of TR and identify higher rates of RV dysfunction in severe TR. eRVEF held stronger association with outcome compared to RVEF.eRVEF calculationKaplan Meier Curves