Prognostic Significance of Flail Mitral Leaflet in Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation

Despite the growing experience with MitraClip in the broad spectrum of mitral regurgitation (MR), limited data are available regarding the independent prognostic role on survival of different mitral regurgitation etiology subtypes. We sought to evaluate the impact of flail leaflet etiology in a large series of patients with primary MR (PMR) who underwent MitraClip treatment. The study included 588 patients with significant PMR from the multicenter GIOTTO (Italian Society of Interventional Cardiology [GIse] registry Of Transcatheter treatment of mitral valve regurgitaTiOn), stratified into 2 groups according to MR etiology: flail (n = 300) and flail (n = 288). The primary end point was a composite of cardiac death and first rehospitalization for heart failure (HF). To account for the baseline differences, patients were propensity score-matched 1:1. Flail leaflet etiology was present in about a half of the patients. Acute technical success was achieved in 98% of the overall cohort, with no significant differences between the study groups (p = 0.789). At the 2-year Kaplan-Meier analysis, the primary end point occurred in 13% of flail patients compared with 23% in flail (p = 0.009). The flail group presented lower rates of both cardiac death and rehospitalization for HF, whereas a similar overall death rate was observed between the groups. A multivariate Cox regression analysis identified flail leaflet etiology as an independent predictor of favorable outcome in terms of the primary end point (hazard ratio 0.141, 95% confidence interval 0.049 to 0.401, p <0.001). After propensity score matching, flail patients had confirmed lower rates of cardiac mortality and rehospitalization for HF but similar rates of overall death. In conclusion, flail leaflet-related etiology was common in patients with PMR who underwent MitraClip treatment and was an independent predictor of midterm favorable clinical outcomes.