Page 69 - Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

Introduction
Secondary mitral regurgitation (MR) in patients with heart failure (HF) arises from impaired left ventricular (LV) geometry and function (1,2). Although patients with secondary MR have a poor prognosis, whether the dysfunctional LV or mitral valve (MV) (i.e., MR) predominantly dictates patient outcomes may be difficult to distinguish (1,3,4). In addition, LV reverse remodeling after MR reduction has been associated with improved prognosis (5,6). However, when selecting patients with severe secondary MR for medical, surgical, or transcatheter treatments, identifying those patients who will show LV reverse remodeling and improvement in LV systolic function, HF symptoms, and prognosis may be difficult. MR quantification is challenging due to its dynamic nature and its dependence on loading conditions as well as LV size and function (2,7). The effective regurgitant orifice area (EROA) and regurgitant volume (RVol) derived using the proximal isovelocity surface area (PISA) method can over- or under-estimate the severity of MR (7), and LV volumes are not directly taken into consideration, which are important for understanding volume overload (1,7). Therefore, a multiparametric approach is recommended when assessing the severity of secondary MR. Current recommendations take the dimensions of the LV into consideration as a binary variable (i.e., dilated vs. nondilated) instead of a continuous variable (8, 9, 10). The relationship between RVol and LV dimensions can be reflected by the ratio between RVol and LV end-diastolic volume (EDV) (7,11,12). For a given RVol, a larger LVEDV will result in a smaller RVol/EDV ratio, suggesting that the degree of LV dilation is disproportionate to the severity of MR. Eliminating MR in such cases offers less potential for reduction in LVEDV than in patients with smaller LVs (11). The prognostic implications of this ratio have not been investigated. Accordingly, we sought to investigate the prognostic implications of the RVol/LVEDV ratio in a large population of patients with significant (moderate and severe) secondary MR.
Methods
Patient population
Patients with HF and at least moderate secondary MR were identified through the departmental echocardiographic database (Imagevault EchoPAC, General Electric Vingmed Ultrasound, Horten, Norway) of Leiden University Medical Center, Leiden, the Netherlands. Patients with previous MV intervention were excluded. Demographic, clinical, and echocardiographic characteristics were collected in the departmental clinical (EPD-Vision 11.8.4.0, Leiden University Medical Center, Leiden, the Netherlands) and echocardiographic databases, and were analyzed retrospectively. For this retrospective study with clinically acquired data, the institutional review board
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