428 Prognostic implications of the relationship between effective regurgitant orifice area and left ventricle end diastolic volume in patients with functional mitral regurgitation treated with MitraClip
Authors: Melillo E , Godino C , Ancona F , Sisinni A , Stella S , Capogrosso C , Camici P G , Denti P , Buzzatti N , Colombo A , Montorfano M , De Bonis M , Castiglioni A , Alfieri O , Agricola E 
Published: January 2020

Abstract

Funding Acknowledgements
none

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 framework 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 was calculated in 137 patients with at least 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 1.1 years. The primary outcome occurred in 59 patients (43 %). Population study showed a LVEDVi 113.52± 32.16 mL/m2, LVEF 29.75± 10.06% and EROA 39.45± 15.43 mm2.. The cut-off value of EROA/LVEDV ratio for primary outcome, identified by receiver operating characteristic curve, was 0.15 (AUC 0,65, p = 0.002) with a sensitivity and specificity of 78% and 52%, respectively. Patients were divided in two groups according to the identified cut-off. Patients with higher ratio (Group I, n = 88) presented a less dilated LV (LVEDVi: 105.1 ± 29.6 mL/m2 vs 128.2 ± 31.9 mL/m2, p &lt; 0.001; LVESVi: 73.1 ± 27.7 mL/m2 vs 94.9 ± 29.05 mL/m2, p &lt; 0.001), and a more severe MR (EROA: 47.9 ± 12.1 mm2 vs 25.1 ± 8.3 mm2, p &lt; 0.001; vena contracta: 7.2 ± 1.3 mm vs 6.5 ± 1.3 mm, p = 0.008). There were no significant differences of left ventricle ejection fraction, right ventricle systolic function and systolic pulmonary pressure between the groups. At univariate analysis, EROA/LVEDV ratio &gt;0.15 (HR = 2.223, 95% CI 1.121-4.411, p = 0.022), baseline evidence of atrial fibrillation (HR = 1.949, 95% CI 1.156-3.283, p = 0.012) and baseline pro-BNP (HR= 1.000, 95% CI 1.000-1.000, p = 0,001) were associated with a worse clinical outcome. At multivariate Cox-regression analysis, both EROA/LVEDV ratio &gt;0.15 and baseline pro-BNP values were identified as independent predictors (HR 2.941, 95% CI 1.035-8.353, p = 0.043; HR = 1.000, 95% CI 1.000-1.000, p = 0.002, respectively). At Kaplan-Meier survival analysis, patients with EROA/LVEDV &gt;0.15 had a significant lower freedom from composite endpoint (log-rank χ2 =5.517, p= 0.019; Fig. 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.
Abstract 428 Figure. Fig. 1