Acute Kidney Injury After Percutaneous Edge-to-Edge Mitral Repair.

Background: In catheter-based procedures, acute kidney injury (AKI) is a frequent, serious complication ranging from 10% to 30%. In MitraClip (Abbott Vascular, Santa Clara, California), a usually contrast-free procedure, there is scarce data about its real incidence and impact.

Objectives: This study aimed to evaluate incidence, predictive factors, and midterm outcomes of AKI in patients with significant mitral regurgitation (MR) undergoing transcatheter valve repair with MitraClip.

Methods: A total of 721 patients undergoing MitraClip were included. AKI was defined as an absolute or a relative increase in serum creatinine of >0.3 mg/dl or ≥50%, respectively, or the need for hemodialysis during index hospitalization.

Results: The mean age of the patients was 72 ± 11 years (28.3% women). Median estimated glomerular filtration rate (eGFR) was 43.7 ml/min/1.73 m (interquartile range: 30.9 to 60.1 ml/min/1.73 m), and was <60 ml/min/1.73 m in 74.9% of the patients. AKI after MitraClip occurred in 106 patients (14.7%). Baseline hemoglobin (<11 g/dl) (odds ratio [OR]: 1.97; p = 0.003), urgent procedure (OR: 3.44; p = 0.003), and absence of device success (OR: 3.37; p < 0.001) were independent predictors of AKI. Patients with AKI had worse outcomes compared to those without AKI, including a higher proportion of in-hospital bleeding events (3.8% vs. 0.8%; p = 0.011), 2-year all-cause mortality (40.5% vs. 18.7%; p <0.001), and major adverse cardiac events (63.6% vs. 23.5%; p <0.001). Combination of AKI with significant residual MR after the procedure conferred even worst outcomes (2-year all-cause mortality 50.0% vs. 19.6%; p = 0.001, and major adverse cardiac events 70.0% vs. 18.9%; p < 0.001).

Conclusions: Despite being a "zero-contrast" procedure, one-sixth of patients undergoing transcatheter mitral valve repair had AKI, linked to device failure or other severe conditions. The occurrence of AKI was associated with worse outcomes, highlighting the importance to detect and reduce this complication in high-risk population.