German MitraClip Registry 1-Year Outcomes
What are the clinical results associated with the MitraClip device for transcatheter treatment of mitral regurgitation (MR)?
The transcatheter mitral valve interventions (TRAMI) registry was established to assess the safety and efficacy of catheter-based mitral valve interventional techniques in Germany, and prospectively enrolled 828 MitraClip patients (median age 76 years, median logistic EuroSCORE I 20.0%) between August 2010 and July 2013. This study addressed the 1-year outcome in this cohort. A total of 749 patients (90.5%) were available for 1-year follow-up and included in the analyses. Mortality, major adverse cardiovascular event rates, and New York Heart Association (NYHA) classes were recorded. Predictors of 1-year mortality were identified by multivariate analysis using a Cox regression model with stepwise forward selection.
The 1-year mortality was 20.3%. At 1 year, 63.3% of TRAMI patients were NYHA functional classes I or II (compared with 11.0% at baseline), and self-rated health status (on EuroQuol visual analogue scale) also improved significantly by 10 points. Importantly, a significant proportion of patients regained the complete independence in self-care after MitraClip implantation (independence in 74.0 vs. 58.6% at baseline, p = 0.005). Predictors of 1-year mortality were NYHA class IV (hazard ratio [HR], 1.62; p = 0.02), anemia (HR, 2.44; p = 0.02), previous aortic valve intervention (HR, 2.12; p = 0.002), serum creatinine ≥1.5 mg/dl (HR, 1.77; p = 0.002), peripheral artery disease (HR, 2.12; p = 0.0003), left ventricular ejection fraction <30% (HR, 1.58; p = 0.01), severe tricuspid regurgitation (HR, 1.84; p = 0.003), and procedural failure (defined as operator-reported failure, conversion to surgery, failure of clip placement, or residual post-procedural severe MR) (HR, 4.36; p < 0.0001).
Treatment of significant MR with MitraClip resulted in significant clinical improvements in a high proportion of TRAMI patients after 12 months. In the TRAMI cohort, the failure of procedural success exhibited the highest HR concerning the prediction of 1-year mortality.
These registry data from Germany suggest that clinical endpoints improve 1 year after MitraClip transcatheter intervention for MR. The registry did not assess the impact on MR severity (which, based on previously published data, is imperfect). Notably, most of the predictors of mortality (advanced NYHA functional class, prior cardiac surgery, elevated creatinine, peripheral artery disease, impaired LV systolic function, and multi-valve disease [TR]) also are indications for transcatheter as opposed to surgical intervention for MR. It will be important to find the correct niche for this transcatheter therapy that appears to offer some clinical improvement, but should not be seen as a substitute for surgical correction of MR.
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