P4728Prognostic implications of the relationship between effective regurgitant orifice area and left ventricle end diastolic volume in patients with functional mitral regurgitation treated with MitraClip

Abstract

Abstract Background The distinction between proportionate and disproportionate functional mitral regurgitation (FMR), based on the relationship between effective regurgitant orifice area (EROA) and left ventricle end diastolic volume (LVEDV), has recently been proposed as a possible new clinical and physiopathological concept to identify patients that could likely benefit from transcatheter mitral repair. Purpose The aim of our study was to explore the possible prognostic implications of the EROA/LVEDV ratio in patients with FMR treated with MitraClip. Methods Baseline EROA/LVEDV ratio was calculated in 72 patients with moderate-to-severe, symptomatic FMR treated with MitraClip. All patients underwent clinical, biochemichal and echocardiographic evaluation before MitraClip. EROA was calculated using PISA method. The primary outcome was a composite end-point of all-cause death or re-hospitalization for heart failure (HF). Results The median follow-up was 1 year. The primary outcome occurred in 25 patients (34.7%). The cut-off value of EROA/LVEDV ratio for primary outcome, identified by receiver operating characteristic curve, was 0.15 (p=0.007) with a sensitivity and specificity of 72 and 68%, respectively. Patients were divided in two groups according to the identified cut-off. Patients with higher ratio (Group I, n=35) presented a less dilated LV (LVEDVi: 113.2±33.4 mL vs 129.3±29.3 mL, p=0.033; LVESV: 140.7±49.0 mL vs 171.1±47.4 mL, p=0.010), a better LV systolic function (LVEF: 31.9±9.5% vs 27.8±5.8%, p=0.028) and a more severe MR (EROA: 44.5±12.9 mm2 vs 24.5±6.8 mm2, p<0.001; vena contracta: 7.4±1.5 mm vs 6.7±1.0 mm, p=0.045). Patients with lower ratio (Group II, n=37) showed a reduced prevalence of MV annular dilation (57.1% vs 91.7%, p=0.005) and a worse RV function (s'TDI: 9.2±2.2 cm/s vs 10.5±2.9 cm/s, p=0.039). At univariate analysis, EROA/LVEDV ratio >0.15 (HR = 2.467, 95% CI 1.017–5.982, p=0.046) and severe pulmonary hypertension (HR = 2.481, 95% CI 1.030–5.976, p=0.043) were associated with a worse clinical outcome. At multivariate Cox-regression analysis, both EROA/LVEDV ratio >0.15 and severe pulmonary hypertension were identified as independent predictors (HR 3.203, 95% CI 1–310–7.832, p=0.011; HR = 3.280, 95% CI 1.326–8.116, p=0.010, respectively). Figure 1 Conclusion Our data show that EROA/LVEDV ratio was an independent predictor of adverse clinical outcome in FMR patients treated with MitraClip. This preliminary experience shows that this index could help to identify subgroups of patients with potential different clinical benefits from MitraClip therapy. However, further and extended data are needed to provide more precise evidence. Acknowledgement/Funding None