Transcatheter "edge-to-edge" mitral valve repair: influence of bias in randomized trials.

Functional mitral regurgitation (FMR) is the result of three-dimensional structural disruption of the mitral valve due to left ventricular dysfunction. The "edge-to-edge" surgical technique has given rise to the percutaneous transcatheter edge-to-edge repair (TEER) technique to treat FMR; however, the lack of a mitral annuloplasty ring makes TEER only partially effective, with uncertain long-term results. The MITRA-FR and COAPT trials, on which current TEER recommendations are based, show conflicting results. COAPT results possible bias has influenced current recommendations issued by clinical practice guidelines in favor of TEER in FMR.