Background Optimizing risk stratification in patients undergoing transcatheter mitral valve repair is an ongoing challenge. The Mitral Regurgitation International Database (MIDA) score represents a user-friendly mortality risk stratification tool that is validated on a large-scale registry of patients with degenerative mitral regurgitation (MR). We here assessed the potential benefit of the MIDA risk score for patients with functional or degenerative MR undergoing transcatheter mitral valve repair. Methods and Results In total, 680 patients undergoing MitraClip implantation were stratified according to MIDA score tertiles into a low (0-7), intermediate (8-9), and a high (10-12) MIDA score group. MR was assessed in follow-up echocardiograms in 416 patients at 323±169 days after transcatheter mitral valve repair. During 2-year follow-up, 8.2% (15/182) of patients with low, 21.3% (64/300) with intermediate, and 26.3% (52/198) with high MIDA score died (log-rank test P<0.001). Hazard of all-cause mortality increased by 13% (95% CI, 3%-25%) with every additional point of the MIDA score. Subanalysis of 431 patients with functional MR showed similar results. Furthermore, rates of a combined end point of mortality and hospitalization for heart failure were higher with increasing MIDA score (30% [54/182], 38% [113/300] and 48% [94/198], respectively, log-rank test P=0.001). Frequency of residual MR ≥II at follow-up increased with increasing MIDA score group (33%, 44%, and 59%, respectively, P<0.001). Conclusions The MIDA mortality risk score maintains its predictive utility in patients undergoing transcatheter mitral valve repair, regardless of MR cause. Moreover, it was predictive of worse event-free survival regarding a combined end point of mortality and hospitalization for heart failure, and was associated with postprocedural residual MR ≥II and MR recurrence.
Keywords: mitral regurgitation; percutaneous mitral valve repair; risk assessment.