Fastener and techniques therefor

1. A method for use with a heart of a subject, the method comprising:

advancing a tool distally along a flexible elongate contracting member, toward an anchor implanted at the heart, the tool including a cutting element;

applying tension to the contracting member such that the contracting member slides proximally through a fastener disposed at the heart, while a stop is removably coupled to the fastener in a manner that maintains the fastener in an open state; and

using the tool, pulling the stop proximally in a manner that moves the stop both:

away from the fastener, such that the fastener responsively clamps to the contracting member, thereby locking the tension in the contracting member, and

against the cutting element of the tool such that the stop pushes the cutting element against the contracting member in a manner that severs the contracting member.

2. The method according to claim 1 , wherein advancing the tool distally along the contracting member comprises advancing the tool distally along the contracting member towards the anchor implanted at the heart, and the fastener.

3. The method according to claim 1 , wherein advancing the tool distally along the contracting member comprises advancing the tool and the fastener distally along the contracting member while the tool is coupled to the fastener via the stop.

4. The method according to claim 1 , wherein applying tension to the contracting member comprises applying the tension to the contracting member using the tool.

5. The method according to claim 1 , wherein:

the fastener defines a lumen for the contracting member to extend therethrough,

in the open state of the fastener, the stop extends through at least part of the lumen, inhibiting the fastener from clamping onto the contracting member; and

using the tool, pulling the stop proximally away from the fastener comprises using the tool, pulling the stop proximally away from the fastener such that the stop exits the lumen of the fastener.

6. The method according to claim 5 , wherein the stop defines a lumen for the contracting member to extend therethrough, and applying tension to the contracting member comprises applying tension to the contracting member such that the contracting member slides through the lumen of the stop while at least a portion of the lumen of the stop extends through the lumen of the fastener.

7. The method according to claim 1 , wherein:

the cutting element comprises a static cutting element having a first cutting surface, and a dynamic cutting element having a second cutting surface, the contracting member passing along the static cutting element and the dynamic cutting element, and

using the tool to pull the stop proximally away from the fastener comprises using the tool to pull the stop proximally away from the fastener such that the stop contacts the dynamic cutting element and applies a proximal force to the dynamic cutting element, causing the dynamic cutting element to slide against the static cutting element.

8. The method according to claim 7 , wherein each of the static cutting element and the dynamic cutting element are diagonal, and wherein using the tool to pull the stop proximally away from the fastener such that the stop contacts the dynamic cutting element and applies the proximal force to the dynamic cutting element comprises using the tool to pull the stop proximally away from the fastener such that the stop causes the dynamic cutting element to slide against the static cutting element in a proximal, diagonal direction.

9. The method according to claim 7 , wherein the static cutting element defines a lumen therethrough, and wherein using the tool to pull the stop proximally away from the fastener comprises using the tool to pull the stop proximally away from the fastener while the contracting member extends through the lumen of the static cutting element.

10. The method according to claim 9 , wherein the dynamic cutting element defines a lumen therethrough, and wherein using the tool to pull the stop proximally away from the fastener comprises using the tool to pull the stop proximally away from the fastener while the contracting member extends through the lumen of the dynamic cutting element.

11. Apparatus for use with a contracting member that is flexible and elongate, the apparatus comprising:

a fastener configured to receive the contracting member therethrough such that the fastener surrounds the contracting member, the fastener comprising a clamping structure that:

(a) has an open state in which the contracting member can pass through the clamping structure, and

(b) is biased toward assuming a closed state in which the clamping structure is configured to clamp onto the contracting member disposed therethrough;

a stop removably coupled to the fastener in a manner that maintains the fastener in the open state; and

a tool:

comprising a cutting element; and

configured to pull the stop proximally in a manner that moves the stop both:

away from the fastener such that the stop becomes removed from the fastener, and

against the cutting element such that the stop pushes the cutting element against the contracting member in a manner that severs the contracting member.

12. The apparatus according to claim 11 , wherein:

the tool is configured to pull the stop proximally along an axis of the tool, and

the cutting element is configured such that the tool pulling the stop proximally along the axis and against the cutting element causes the cutting element to slide in a direction that is oblique with respect to the axis.

13. The apparatus according to claim 11 , wherein the tool is arranged such that the tool provides a safety mechanism whereby movement of the cutting element is possible only by pulling of the stop against the cutting element.

14. The apparatus according to claim 11 , wherein the stop is shaped so as to define an overhang, and wherein the tool further comprises graspers, the graspers configured to grip the overhang in order to couple the tool to the fastener.

15. The apparatus according to claim 11 , wherein:

the cutting element is a dynamic cutting element having a first cutting surface,

the tool further comprises a static cutting element having a second cutting surface, the fastener being configured to receive the contracting member therethrough such that the contracting member passes along the static cutting element and the dynamic cutting element, and

the tool is configured to pull the stop proximally against the dynamic cutting element such that the dynamic cutting element slides against the static cutting element.

16. The apparatus according to claim 15 , wherein each of the first and second cutting surfaces is oblique with respect to an axis along which the tool is configured to pull the stop.

17. The apparatus according to claim 15 , wherein the static cutting element defines a lumen for the contracting member to extend therethrough.

18. The apparatus according to claim 17 , wherein the dynamic cutting element defines a lumen for the contracting member to extend therethrough.

19. The apparatus according to claim 11 , further comprising the contracting member, and an anchor coupled to the contracting member.

20. The apparatus according to claim 19 , wherein the tool is further configured to apply tension to the contracting member.

21. The apparatus according to claim 20 , wherein:

the anchor is a first anchor, and

the apparatus further comprises a second anchor, slidably coupled to the contracting member, and wherein the fastener is configured to, in the closed state, maintain a distance between the first anchor and the second anchor by locking the tension in the contracting member.

22. A method for use with a heart of a subject, the method comprising:

advancing a tool distally along a flexible elongate contracting member, toward an anchor implanted at the heart, the tool including a cutting element;

applying tension to the contracting member such that the contracting member slides proximally through a fastener disposed at the heart, while a stop is removably coupled to the fastener in a manner that maintains the fastener in an open state; and

using the tool, pulling the stop proximally away from the fastener and against a cutting element of the tool in a manner that causes both:

the fastener to clamp to the contracting member, thereby locking the tension in the contracting member, and

the stop to push the cutting element against the contracting member to sever the contracting member.