Objectives

Acute and chronic renal disease are associated with an increased risk for patients undergoing cardiac interventions.

Transcatheter mitral valve repair (TMVR) by MitraClip implantation has been emerged as standard-of-care for mitral regurgitation (MR) grade 3+/4+ in patients who are not amendable to open-heart surgery. In this study, we analyzed the impact of acute and chronic kidney injury on outcomes in patients treated by TMVR.

Methods and results

Between 09/2008 to 11/2013, 672 patients (n=464 from Hamburg University and n=210 from Göttingen University: 75±9 years, predominantly male gender (62%), median logistic EuroSCORE 22% [13; 36], functional MR 63%) were treated by TMVR. Follow-up was carried out by ambulatory visits and telephone follow-up. Median follow-up time was median follow-up time 4.1 [4.0; 4.3] years.

There were 524 patients without and 121 with acute kidney injury (n=102 in AKIN=1; n=16 in AKIN=2 and n=3 in AKIN=3) according to the MVARC criteria. Subgroup stratification for GFR-rates revealed 323 patients with moderate and 56 patients with severe CKD, leaving 287 patients without chronic kidney disease at baseline. Significant less females were suffering from CKD (52% without vs. 18% with severe CKD, p<0.0001).

Procedural success was achieved in 620 cases (92.3%) without differences for neither AKI or CKD subgroups. A mean number of 1.4±0.6 clips was implanted, again without significant differences within the subgroups.

In Kaplan-Meier analysis, worse survival rates were found for AKI patients for both the composite endpoint (death or rehospitalization, p log rank <0.001) as well as for mortality (p log rank <0.001). CKD subgroups according to GFR-rates (moderate CKD: GFR≤60ml/min, but ≥30ml/min and severe CKD: GFR<30ml/min) indicated the worst outcome for severe CKD patients, intermediate outcome for moderate CKD and superior survival and rehospitalization rates for patients without CKD (p log rank <0.001).

The risk of AKI is 1.7-times higher in patients already suffering from CKD (95%-CI: 1.1; 2.64, p=0.01). In direct comparison, lowest survival rates are found in patients suffering from both AKI and CKD, whereas trend-wise AKI patients without CKD do worse than CKD patients without AKI (Kaplan-Meier analysis, Figure 1, p<0.0001).

Acute kidney injury proved as independent predictor of mortality in univariate Cox regression (HR: 2.33; 95%-CI: 1.75-3.11; p<0.001). The association was less strong for CKD (HR: 1.43; 95%-CI: 1.11-1.84; p=0.006).

Conclusions