This study aims to investigate the efficacy and safety of combined mitral and tricuspid transcatheter edge-to-edge repair (TEER) versus isolated mitral TEER in the treatment of patients with mitral regurgitation (MR) combined with tricuspid regurgitation (TR). The expected objective is to provide a more precise treatment strategy for patients with MR combined with TR, reduce surgical risks, improve survival rates and quality of life, and offer evidence for clinical practice. The main research content involves enrolling 404 patients with severe MR combined with TR, who will be randomly assigned to either the group receiving simultaneous mitral and tricuspid TEER or the group receiving isolated mitral TEER. The primary endpoint is the composite endpoint at one year postoperatively, including death during the one-year follow-up, mitral and/or tricuspid surgery or intervention due to mitral and/or tricuspid dysfunction, rehospitalization for heart failure, and an increase of \<15 points in the KCCQ score.