Delivery systems for implantable medical devices, and associated tethering assemblies and methods

1. A delivery system for a relatively compact implantable medical device, the system comprising:

an elongate inner shaft;

an elongate outer shaft in sliding engagement around the inner shaft;

a handle coupled to the elongate inner shaft and elongate outer shaft, the handle including a proximal port at a proximal end of the handle, the inner shaft including a first lumen and a second lumen, both lumens extending longitudinally along a length of the inner shaft from proximal openings thereof to distal openings thereof, one or both of the proximal openings being in fluid communication with the proximal port, the distal openings being located at a distal end of the inner shaft, and the outer shaft including a distal-most portion sized to contain the medical device therein;

an elongate tool extending within the first lumen of the inner shaft and being in sliding engagement therein, the elongate tool including a proximal end accessible in proximity to the proximal port, and a distal end protruding from the distal end of the inner shaft, the distal end of the tool including a coupling feature; and

an elongate tethering member including a first end, a second end, a first segment, a second segment, and a retainer, the first segment extending within the second lumen of the inner shaft from the first end to the second segment, the second segment extending from the first segment to the second end and distally from the distal end of the inner shaft, the first end protruding from the proximal port and being joined to the retainer proximal to the proximal port of the handle, and the second segment being configured to engage with a holding member of the medical device; and

wherein the coupling feature of the tool is configured to couple with the second segment of the tethering member and to transfer a pull force thereto, when the pull force is applied to the proximal end of the tool, the pull force drawing the coupled second segment of the tethering member into the first lumen of the inner shaft, through the distal opening thereof.

2. The system of claim 1 , wherein the second segment of the tethering member has a length that is significantly less than a length of the first segment of the tethering member.

3. The system of claim 2 , wherein:

the coupling feature of the tool comprises a hook; and

the second segment of the tethering member has a loop formed therein at the second end.

4. The system of claim 1 , wherein a length of the first segment of the tethering member is approximately equal to a length of the second segment of the tethering member.

5. The system of claim 4 , wherein the retainer of the tethering member is configured for attaching to the second end of the tethering member.

6. The system of claim 5 , wherein the coupling feature of the tool comprises a contractible loop configured to contract from a first loop size to a smaller second loop size.

7. The system of claim 1 , wherein:

the coupling feature of the tool comprises a hook; and

the second segment of the tethering member has a loop formed therein at the second end.

8. The system of claim 1 , wherein the coupling feature of the tool comprises a contractible loop configured to contract from a first loop size to a smaller second loop size.

9. The system of claim 8 , wherein the contractible loop is configured to contract from the first loop size to the smaller second loop size by applying a pull force to the proximal end of the elongate tool.

10. The system of claim 1 , wherein the retainer is configured to prevent the first end of the tethering member from being pulled into the second lumen.

11. The system of claim 1 , wherein the coupling feature of the tool comprises a hook configured to couple with the second segment of the tethering member.

12. The system of claim 1 , wherein the holding member comprises an eyelet configured to engage the second segment of the tethering member when the second segment is threaded through the eyelet.

13. A method for tethering a relatively compact implantable medical device to a delivery system, the method comprising:

engaging a second segment of an elongate tethering member of the delivery system with a holding member of the medical device, wherein the delivery system comprises:

an elongate inner shaft

an elongate outer shaft in sliding engagement around the inner shaft

a handle coupled to the elongate inner shaft and elongate outer shaft, the handle including a proximal port at a proximal end of the handle, the inner shaft including a first lumen and a second lumen, both lumens extending longitudinally along a length of the inner shaft from proximal openings thereof to distal openings thereof, one or both of the proximal openings being in fluid communication with the proximal port, the distal openings being located at a distal end of the inner shaft, and the outer shaft including a distal-most portion sized to contain the medical device therein;

an elongate tool extending within the first lumen of the inner shaft and being in sliding engagement therein, the elongate tool including a proximal end accessible in proximity to the proximal port, and a distal end protruding from the distal end of the inner shaft, the distal end of the tool including a coupling feature; and

the elongate tethering member including a first end, a second end, a first segment, the second segment, and a retainer, the first segment extending within the second lumen of the inner shaft from the first end to the second segment, the second segment extending from the first segment to the second end and distally from the distal end of the inner shaft, the first end protruding from the proximal port and being joined to the retainer proximal to the proximal port of the handle, and the second segment being configured to engage with the holding member of the medical device; and

wherein the coupling feature of the tool is configured to couple with the second segment of the tethering member and to transfer a pull force thereto, when the pull force is applied to the proximal end of the tool, the pull force drawing the coupled second segment of the tethering member into the first lumen of the inner shaft, through the distal opening thereof;

coupling the distal end of the elongate tool to the engaged second segment of the tethering member;

applying the pull force to the coupled tool until the coupled segment of the tethering member is drawn into the first lumen of the system inner shaft and the device abuts the distal end of the inner shaft; and

securing the elongate tool in position after applying the pull force.

14. The method of claim 13 , further comprising retracting the outer shaft relative to the inner shaft of the system, so that the distal end of the inner shaft is exposed distal to a distal-most portion of the outer shaft, before engaging the second segment of the tethering member.

15. The method of claim 13 , wherein coupling the distal end of the tool to the engaged segment of the tethering member comprises engaging a hook formed in the distal end of the tool with a loop formed in the segment of the tethering member.

16. A method for tethering a relatively compact implantable medical device to a delivery system, the method comprising:

engaging a second segment of an elongate tethering member of the delivery system with a holding member of the medical device:

an elongate inner shaft

an elongate outer shaft in sliding engagement around the inner shaft

a handle coupled to the elongate inner shaft and elongate outer shaft, the handle including a proximal port at a proximal end of the handle, the inner shaft including a first lumen and a second lumen, both lumens extending longitudinally along a length of the inner shaft from proximal openings thereof to distal openings thereof, one or both of the proximal openings being in fluid communication with the proximal port, the distal openings being located at a distal end of the inner shaft, and the outer shaft including a distal-most portion sized to contain the medical device therein;

an elongate tool extending within the first lumen of the inner shaft and being in sliding engagement therein, the elongate tool including a proximal end accessible in proximity to the proximal port, and a distal end protruding from the distal end of the inner shaft, the distal end of the tool including a coupling feature; and

the elongate tethering member including a first end, a second end, a first segment, the second segment, and a retainer, the first segment extending within the second lumen of the inner shaft from the first end to the second segment, the second segment extending from the first segment to the second end and distally from the distal end of the inner shaft, the first end protruding from the proximal port and being joined to the retainer proximal to the proximal port of the handle, and the second segment being configured to engage with the holding member of the medical device; and

wherein the coupling feature of the tool is configured to couple with the second segment of the tethering member and to transfer a pull force thereto, when the pull force is applied to the proximal end of the tool, the pull force drawing the coupled second segment of the tethering member into the first lumen of the inner shaft, through the distal opening thereof;

coupling the distal end of the elongate tool to the engaged second segment of the tethering member;

applying the pull force to the coupled tool until the coupled segment of the tethering member is drawn through the first lumen of the system inner shaft and the second end of the tethering member protrudes from a proximal port of the system;

uncoupling the tool distal end from the engaged second segment of the tethering member when the second end of the tethering member protrudes from the proximal port of the system; and

attaching the second end of the tethering member that protrudes from the system proximal port to the retainer of the tethering member.

17. The method of claim 16 , further comprising retracting the outer shaft of the system relative to the inner shaft of the system, so that the distal end of the inner shaft is exposed distal to a distal-most portion of the outer shaft, before engaging the second segment of the tethering member.

18. The method of claim 16 , coupling the distal end of the tool to the engaged second segment of the tethering member comprises passing the second segment through a contractible loop of the tool and then contracting the contractible loop.

19. The method of claim 16 , wherein attaching the second end of the tethering member that protrudes from the system proximal port to the retainer comprises capturing the second end in a press fit between opposing interlocking parts of the retainer.