Disclosed herein are representative embodiments of methods, apparatus, and systems used to deliver a prosthetic heart valve to a deficient valve. In one embodiment, for instance, a support stent is delivered to a position on the surface of the outflow side of a native heart valve of a patient, the support stent defining a support-stent interior. An expandable prosthetic heart valve is delivered into the native heart valve from the inflow side of the native heart valve and into the support-stent interior. The expandable prosthetic heart valve is expanded while the expandable prosthetic valve is in the support-stent interior and while the support stent is at the position on the surface of the outflow side of the heart valve, thereby causing one or more of the native leaflets of the native heart valve to be frictionally secured between the support stent and the expanded prosthetic heart valve.