Aims: Factors predicting outcomes after MitraClip implantation are not well defined. We aimed to report the influence of baseline renal function on short-term outcomes of patients enrolled in the investigator-initiated German transcatheter mitral valve interventions (TRAMI) registry.
Methods and results: Twenty participating German centres prospectively included 778 patients (mean age 76.0 years [71-81], 38.8% female gender) at high surgical risk (mean logistic EuroSCORE 20% [12-32%]) undergoing TMVR with the MitraClip for the treatment of symptomatic functional (70%) or degenerative (30%) mitral valve regurgitation (FMR, DMR). The patients were stratified according to renal function before clip implantation. The prevalence of moderate to severe renal impairment (glomerular filtration rate [GFR] <60 ml/min) was 62.7% (37.3%, normal renal function [GFR >60 ml/min]; 49.6%, moderate renal impairment [GFR 30-60 ml/min]; 13.1%, severe renal impairment [GFR <30 ml/min]). TMVR was successfully completed in 98.2% of cases; acute procedural failure, in-hospital and 30-day mortality rates were 1.8%, 2.3% and 4.4%, respectively. Acute procedural failure and mortality rates (in-hospital, 30-day) were significantly higher in patients with severe renal impairment (5.9%, 7.8%, 14.1%), as compared to patients with moderately (1%, 1.3%, 3.0%) or mildly impaired to normal (1.4%, 1.7%, 2.9%) renal function (p<0.0001). Following Cox regression analysis, the prevalence of severe renal impairment at the time of TMVR was the only predictor for increased 30-day mortality rates (hazard ratio 3.42, 95% confidence interval 1.88-6.2; p<0.0001).
Conclusions: Renal function at the time of interventional mitral valve repair with the MitraClip system is a strong predictor for procedural outcomes. Patients with severe renal impairment have a more than threefold increased risk for acute procedural failure, in-hospital death and 30-day mortality.