a stentless support structure capable of being at least partly assembled in situ . the support structure comprises a braided tube that is very flexible and , when elongated , becomes very long and very small in diameter , thereby being capable of placement within a small diameter catheter . the support structure is preferably constructed of one or more thin strands of a super - elastic or shape memory material such as nitinol . when released from the catheter , the support structure folds itself into a longitudinally compact configuration . the support structure thus gains significant strength as the number of folds increase . this radial strength obviates the need for a support stent . the support structure may include attachment points for a prosthetic valve .