Stent delivery system having anisotropic sheath
A stent delivery system and methods are described. The stent delivery system can include an elongate outer member defining an outer member lumen through which a self-expanding stent is deliverable. The elongate outer member can include an anisotropic portion and a rigid portion proximal to the anisotropic portion. The anisotropic portion can be radially elastic and longitudinally inelastic. The rigid portion can be radially inelastic and longitudinally inelastic.
1. A method of delivering a self-expanding stent using a stent delivery system, the method comprising:
advancing the stent delivery system over a guidewire, the stent delivery system comprising:
an elongate outer member defining an outer member lumen, the elongate outer member comprising:
an anisotropic portion, the anisotropic portion being radially elastic and longitudinally inelastic, and
a rigid portion proximal to the anisotropic portion, the rigid portion being radially inelastic and longitudinally inelastic;
a guidewire channel positioned radially inward of the elongate outer member, the guidewire insertable into a lumen of the guidewire channel; and
a pusher assembly in the outer member lumen,
wherein the self-expanding stent is positioned radially inward of the anisotropic portion of the elongate outer member in a compressed configuration, the anisotropic portion of the elongate outer member being at least as long as the self-expanding stent in the compressed configuration, the self-expanding stent comprising flared proximal and distal ends in the compressed configuration, parts of the anisotropic portion surrounding the flared ends of the self-expanding stent in the compressed configuration; and
advancing the self-expanding stent out of the elongate outer member, wherein advancing the self-expanding stent out of the elongate outer member comprises expanding the self-expanding stent from the compressed configuration to an expanded configuration,
wherein during advancing the self-expanding stent out of the elongate member, a diameter of the anisotropic portion surrounding the flared ends of the self-expanding stent in the compressed configuration is greater than the anisotropic portion not surrounding the flared ends of the self-expanding stent in the compressed configuration.
2. The method of claim 1 , wherein advancing the self-expanding stent out of the elongate outer member comprises distally advancing the pusher assembly.
3. The method of claim 2 , wherein advancing the self-expanding stent further comprises acting on a proximal end of the self-expanding stent.
4. The method of claim 1 , wherein advancing the self-expanding stent out of the elongate outer member comprises proximally retracting the elongate outer member and maintaining position of the self-expanding stent using the pusher assembly.
5. The method of claim 1 , wherein advancing the self-expanding stent out of the elongate outer member comprises proximally retracting the elongate outer member and distally advancing the pusher assembly.
6. The method of claim 5 , wherein proximally retracting the elongate outer member and distally advancing the pusher assembly are at least partially simultaneous.
7. The method of claim 1 , wherein advancing the self-expanding stent comprises radially expanding an inwardly tapered distal end of the elongate outer member.