Collapsible/expandable prosthetic heart valves with non-expanding stent posts and retrieval features

A frame structure for a prosthetic heart valve comprising:

• a plurality of Y-shaped structures disposed in an annular array in which the Y-shaped structures are spaced from one another in a direction that is annular of the array, each of the Y-shaped structures including a base member having a first free end portion and an opposite second end to which a first end of each of two arms of the Y-shaped structure is connected, the arms of each of the Y-shaped structures diverging from one another in a direction away from the second end to define a space between the arms, the space extending in the annular direction;
• and
• a plurality of connecting structures, each connecting structure extending between a respective pair of annularly adjacent ones of the Y-shaped structures, each connecting structure interconnecting the Y-shaped structures in the associated pair, each connecting structure being collapsible and re-expandable in the annular direction, each of the Y-shaped structures being sufficiently strong to maintain at least 75% of the space between its arms when the array is subjected to an annular collapsing force that collapses the array to 50% of an initial annular size,
• wherein the arms of the Y-shaped structures are not shared by any of the connecting structures.