A skirt for an implantable prosthetic device can include an annular fabric matrix radially expandable from a radially compressed configuration to a first diameter upon application of a radially outwardly directed force via the implantable prosthetic device, and a plurality of frangible restriction filaments embedded in the fabric matrix. Each restriction filament can have a selected maximum diameter different from that of at least one of the other restriction filaments, and each restriction filament can break when a radially outwardly directed force applied to the restriction filament exceeds a predetermined threshold.