Stent delivery system having anisotropic sheath

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 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 is less than or equal to a diameter of at least one of the parts the anisotropic portion surrounding at least one of the flared ends of the self-expanding stent in the compressed configuration.