Elevated Mitral Valve Pressure Gradient After MitraClip Implantation Deteriorates Long-Term Outcome in Patients With Severe Mitral Regurgitation and Severe Heart Failure.

ABSTRACT

OBJECTIVES: This single-center study was performed to analyze the effect of an increased transvalvular gradient after the MitraClip (MC) (Abbott Laboratories, Abbott Park, Illinois) procedure on patient outcome during follow-up. BACKGROUND: Percutaneous transcatheter repair of the mitral valve with the MC device has been established as a novel technique for patients with severe mitral regurgitation and high surgical risk. This study investigated the influence of an increased pressure gradient after MC implantation on the long-term outcome of patients. METHODS: A total of 268 patients were enrolled, who received MC implantation between April 2009 and July 2014 in our institution (75 ± 9 years of age, 68% men, weight 76 ± 15 kg, median N-terminal pro-B-type natriuretic peptide 3,696 [interquartile range 1,989 to 7,711] pg/ml, left ventricular ejection fraction 39 ± 16%, log European System for Cardiac Operative Risk Evaluation score 20% [interquartile range 12% to 33%]). Pressure in the left atrium and left ventricle were measured during the procedure using fluid-filled catheters. The pressure gradients over the mitral valve were determined simultaneously invasively and echocardiographically directly after MC deployment. A Kaplan-Meier analysis was performed and correlated with the pressure gradients. We used a combined primary endpoint all-cause-mortality, left ventricular assist device, mitral valve replacement, and redo procedure. RESULTS: The Kaplan-Meier-analysis showed a significantly poorer long-term-outcome in the case of an invasively determined mitral valve pressure gradient (MVPG) in excess of 5 mm Hg at implantation for the combined endpoint (p = 0.001) and for all-cause mortality (p = 0.018). For the echocardiographically determined MVPG the cutoff value was 4.4 mm Hg. Propensity score matching was used to balance baseline differences between the groups. In a Cox model the increased residual MVPG >5 mm Hg was a significant outcome predictor in univariate and multivariate analysis (hazard ratio 2.3; 95% confidence interval 1.4 to 3.8; p = 0.002, multivariate after adjustment for N-terminal pro-B-type natriuretic peptide, age, and remaining mitral regurgitation). CONCLUSIONS: It is recommended that the quality of the implantation result be analyzed carefully and repositioning of the MC be considered in the case of an elevated pressure gradient over the mitral valve.