Impact of disproportionate secondary mitral regurgitation in patients undergoing edge-to-edge percutaneous mitral valve repair

Aims: The aim of this study was to evaluate the prognostic role of echocardiographic parameters assessing secondary mitral regurgitation (SMR) severity and left ventricular dimension, including proportionate versus disproportionate SMR, in MitraClip recipients.

Methods and results: We analysed 137 patients undergoing MitraClip implantation for SMR at three centres. SMR was classified as proportionate or disproportionate based on the median value of the ratio between effective regurgitant orifice area (EROA) and left ventricular end-diastolic volume (LVEDV). The primary endpoint was a composite of cardiovascular mortality and heart failure hospitalisation at two-year follow-up. Mean age was 70±10 years, 80% were male, and median EuroSCORE II was 5.7%. No differences were observed in the disproportionate compared to the proportionate group except for a more severe NYHA class and their expected higher EROA and lower LVEDV. Number of clips deployed, device success and procedural success were similar between the two groups. Residual mitral regurgitation (MR) >1+ at 30 days was more common among patients with an EROA >0.42 cm2 compared to those with an EROA ≤0.42 cm2 (81.3% vs 58%; p=0.004). The relative risk of the primary endpoint was independent from any echocardiographic parameter, including the presence of disproportionate SMR. The only independent predictors of clinical events were EuroSCORE II >8%, NYHA class and residual MR >1+ at 30 days.

Conclusions: Echocardiographic parameters, including the EROA/LVEDV ratio, do not have independent prognostic value in patients undergoing MitraClip implantation. High surgical risk, advanced symptoms and non-optimal MR reduction increase the relative risk of two-year clinical events.

Visual summary. Distribution of effective regurgitant orifice area (EROA) and left ventricular end-diastolic volume (LVEDV) in our population and in those of the COAPT and MITRA-FR trials according to the proportionate/disproportionate classification of secondary mitral regurgitant (SMR) proposed by Grayburn et al (A). Kaplan-Meier curves for the primary endpoint (cardiovascular death or HF hospitalisation at 2 years post MitraClip) of the population stratified by the presence of proportionate SMR (EROA/LVEDV ratio below the median value) or disproportionate SMR (EROA/LVEDV ratio above the median value) (B). Residual SMR (30 days post MitraClip) in patients with baseline EROA above or below the median value (C). Multivariable analysis for the primary endpoint (D).