Heart valve stents adapted for post-implant expansion

A prosthetic heart valve adapted for post-implant expansion, comprising:

• a valve member including an inner structural support stent formed by a radially outer band and a radially inner band, the radially outer band being located concentrically around and in contact with the radially inner band, the support stent having upstanding commissure posts extending in an outflow direction alternating with arcuate inflow cusps, the support stent defining an implant circumference that is non-compressible in normal physiological use and has a first diameter, and wherein the inner band includes expandable segments formed by weakened areas located below each of the commissure posts that enable the inner band to rupture and expand from the first diameter to a second diameter larger than the first diameter upon application of an outward dilatory force from within the support stent substantially larger than forces associated with normal physiological use.