(MitraClip in Non-Responders to Cardiac Resynchronization Therapy)

Functional mitral regurgitation (FMR) is a common finding in patients with dilated cardiomyopathy and reduced left ventricular ejection fraction (LVEF). The presence of a relevant FMR (grade ≥2) is associated with a higher morbidity and mortality. Cardiac resynchronization therapy (CRT) has been shown to be effective in patients with dilated cardiomyopathy and reduced LVEF. In selected patients, CRT has been linked to clinical improvement and reduced mortality. Importantly, 38% of patients with clinical indication for CRT present moderate or severe (FMR). Although FMR might be reduced after CRT, the persistence of a relevant FMR (≥2) after CRT ranges between 40% and 50% and is an independent predictor of no clinical response. In these patients, surgical FMR correction is frequently turned down as a result of a high surgical risk. Percutaneous repair of the mitral valve with the MitraClip system has demonstrated promising results in patients with dilated cardiomyopathy and reduced LVEF5. In a cohort of patients with no response to CRT and FMR ≥2, Auricchio et al showed significant clinical improvement with LVEF recovery and reduction in left ventricle (LV) volumes after MitraClip. The absence of randomization, the retrospective nature of the study and the subsequent selection biases were however major limitations that impeded solid conclusions. The objective of the present study is to assess the efficacy and safety of the MitraClip system in non-responders to CRT and FMR ≥2.