Stentless support structure
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.
1. A stentless support structure comprising:
at least one strand braided to form a tubular structure having a first configuration and a second configuration;
whereby in the first configuration, the tubular structure includes:
a first end and a second end;
an elongate body between the first end and the second end and having a distal portion near the first end, and a proximal portion near the second end, the distal portion separated from the proximal portion by a preformed fold that is unfolded in the first configuration;
whereby in the second configuration, the preformed fold becomes folded and causes the proximal portion to invert into a lumen of the distal portion, thereby creating a section of the body having more than one ply;
whereby the first configuration is maintained when the support structure is constrained within a catheter and the support structure tends to assume the second configuration when unconstrained.
2. The stentless support structure of claim 1 wherein said preformed fold reduces a length of the body in the second configuration.
3. The stentless support structure of claim 1 wherein said tubular structure comprises a single ply in the first configuration.
4. The stentless support structure of claim 1 wherein said tubular structure comprises a multi-ply section in the second configuration.
5. The stentless support structure of claim 4 further comprising a lining sandwiched between said first and second ply.
6. The stentless support structure of claim 1 whereby, in the first configuration, said stentless support structure is capable of being housed with a lumen of a 20Fr catheter.
7. The stentless support structure of claim 1 wherein said second end comprises a folded end.
8. The stentless support structure of claim 1 wherein said plurality of strands braided together to form a tubular structure comprises a plurality of strands of a first diameter and at least one fiber of a second diameter larger than the first diameter.
9. The stentless support structure of claim 1 wherein said first end comprises a wire form having a plurality of commissural attachment points.
10. The stentless support structure of claim 1 further comprising a lining in an inner wall of the tubular structure.