Delivery system assemblies for implantable medical devices
A delivery system assembly includes an elongate inner member that extends distally through a lumen of an elongate outer tube of the assembly; the outer tube is moveable relative to the inner member between first and second positions to deploy an implantable medical device that is held within the outer tube lumen. The inner member may include a flared distal end that abuts, and preferably conforms to, the proximal end of the device, when the device is held within the outer tube lumen. The assembly further includes a stability sheath that surrounds a limited length of the outer tube, in proximity to the handle, to provide an interface for both an operator, who handles the assembly, and for an introducer sheath that provides passage for the assembly into the venous system, so that movement of the outer tube is not hindered by either during device deployment.
1. A delivery system assembly facilitating deployment of an implantable medical device, the assembly comprising:
a handle including at least one control member; an elongate inner member including a proximal end fixed within the handle, and a flared distal end spaced distally apart from the handle and configured to conform to a proximal end of the implantable medical device, wherein the elongate inner member includes a pull wire extending from a proximal end thereof, contained within the handle, to a distal end thereof anchored to the inner member in proximity to the flared distal end of the inner member;
an elongate outer tube forming a lumen in which the inner member extends, the outer tube including a proximal end and a distal end, the proximal end of the outer tube being contained within the handle and coupled to one of the at least one control member of the handle, the lumen of the outer tube being sized to hold the medical device in proximity to the distal end of the outer tube, and to allow retraction of the outer tube relative to the inner member, from a first position to a second position, the retraction of the outer tube being controlled by the control member to which the proximal end of the outer tube is coupled, and the first position corresponding to the distal end of the outer tube being spaced distally from the flared distal end of the inner member so that an entirety of the medical device can be contained within the lumen of the outer tube between the distal end thereof and the flared distal end of the inner member at the first position; and
a stability sheath surrounding a length of the outer tube and including a proximal end fixed to the handle, the stability sheath being relatively rigid and allowing movement of the outer tube relative thereto, for retraction;
wherein the length of the outer tube surrounded by the stability sheath is less than a distance between the handle and the distal end of the outer tube, when the outer tube is in either the first position or the second position.
2. The assembly of claim 1 , wherein the length of the outer tube surrounded by the stability sheath is between approximately 15 cm and approximately 53 cm.
3. The assembly of claim 2 , wherein the distance between the handle and the distal end of the outer tube, when the outer tube is in the first position, is between approximately 103 cm and approximately 107 cm.
4. The assembly of claim 1 , wherein the stability sheath comprises an inner polymer layer adhered to an outer polymer layer by a compatible extrudable tie-layer resin.
5. The assembly of claim 4 , wherein the inner polymer layer of the stability sheath comprises a relatively lubricious polymer.
6. The assembly of claim 1 , wherein an inner surface of the stability sheath is spaced apart from the outer tube by a radial gap between approximately 0.002 inch and approximately 0.01 inch.
7. The assembly of claim 1 , further comprising a valve interface overlay surrounding the stability sheath in proximity to the handle, the overlay being slidable over the stability sheath for repositioning of the overlay with respect to the handle.
8. The assembly of claim 1 , wherein, when the outer tube is in the first position and the proximal end of the medical device abuts the flared distal end, an entirety of the medical device is contained within the outer tube, in proximity to the distal end thereof.
9. The assembly of claim 1 , wherein the second position corresponds to the distal end of the outer tube being approximately aligned with the flared distal end of the inner member.
10. The assembly of claim 1 , wherein a distance between the first position and the second position ranges from approximately 2 cm to approximately 6 cm.
11. The assembly of claim 1 , wherein the flared distal end of the inner member is radiopaque.
12. The assembly of claim 1 , wherein a distal portion of the lumen of the outer tube between the distal end of the outer tube and the flared distal end of the inner member has a length corresponding to the length of the entirety of the medical device.
13. The assembly of claim 1 , wherein in the first position, the distal end of the outer tube and the flared distal end of the inner member are spaced apart by a first length that corresponds to a length of the entirety of the medical device.