A mitral valve prosthesis, a tricuspid valve prosthesis and a stent thereof. The stent is configured to support the heart valves of the mitral valve prosthesis and has a contracted configuration for delivery and an expanded configuration for deployment. The stent comprises, along its axial direction, an inflow section, a transition section and an outflow section, and the transition section is connected to the inflow section at one end and to the outflow section at the other end. When in the expanded configuration, the inflow section is located upstream of the outflow section with respect to the blood flow direction. The inflow section is less radially rigid than the outflow section and/or the transition section. Due to such a small radial rigidity, the inflow section can well adapt itself to the anatomy of the native mitral annulus. As a result, its pressure and interference on the aortic valve can be reduced, resulting in a significant decrease in the risk of leading to occlusion of the left ventricular outflow section. Additionally, during the release, the inflow section can adapt itself to changes in the diameter of the stent and thereby buffer radial deformation and axial displacement of the stent during its expansion, thus enhancing the release reliability.
