A collapsible and expandable prosthetic heart valve stent is provided and comprising an outer section, a valve support defining a flow channel therethrough, a transition section configured to smoothly transition the outer section to the valve support. The valve support is disposed within an interior defined by the outer section, with the inflow end of the valve support disposed inside the outer section's interior. In some cases, the outflow end of the valve support is at least partially defined by the transition section. The prosthetic leaflets are disposed on the inner surface of the valve support's flow channel and are located at or above the annulus of the heart chamber. A prolapse prevention system is attached to the stent to mitigate native valve leaflet prolapse.