Prosthesis, delivery device and methods of use

A method for delivering a replacement heart valve to replace a native heart valve between an atrium and a ventricle of a heart using a delivery system, the method comprising:

• delivering a distal end of the delivery system using a transfemoral delivery approach into the atrium of the heart and toward the native heart valve between the atrium and the ventricle, wherein the delivery system comprises an outer sheath assembly, a mid shaft assembly and an inner assembly, wherein the outer sheath assembly and the mid shaft assembly at least partially retain the replacement heart valve in a radially compacted state over the inner assembly;
• with the distal end of the delivery system within the ventricle of the heart, proximally retracting the outer sheath assembly to expose distal anchors of the replacement heart valve and to allow the distal anchors to self-expand into an expanded state, while a portion of the replacement heart valve remains retained in an at least partially radially compacted state by the mid shaft assembly;
• positioning the distal anchors to engage one or more native leaflets of the native heart valve;
• and
• releasing a retained portion of the replacement heart valve from the mid shaft assembly to fully expand the replacement heart valve from the delivery system, wherein the releasing step comprising proximally retracting the mid shaft assembly relative to the inner assembly to disengage the mid shaft assembly from the proximal end of the replacement mitral valve to allow a proximal anchoring portion of the replacement mitral valve to self-expand into a radially expanded state.