阅读说明：本技术 用于在心脏瓣膜环周围将收缩绳索保持在减小直径状态的紧固件和该紧固件的安装 (Fastener for maintaining a contraction cable in a reduced diameter state around a heart valve annulus and installation of the fastener ) 是由 B·莫德西特 D·纽马克 于 2018-12-28 设计创作，主要内容包括：先前已经固定在环上的绳索可以使用锁定在壳体中的滑动构件来紧固。在将这两部分锁定在一起之前,绳索能够自由滑动通过滑动构件中的通道,并且剪切销防止滑动构件移动。在这两部分锁定在一起之后,绳索的一部分被挤压在滑动构件的上表面和壳体的一个壁之间,绳索的其他部分被挤压在滑动构件的下表面和壳体的另一个壁之间,使得绳索不再能够滑动。在锁定之后,滑动切割元件可以被致动以切掉绳索的相对于这两个被锁定的部分位于近侧的部分。(The cord, which has previously been secured to the loop, may be secured using a sliding member locked in the housing. The cord is free to slide through the passage in the slide member before locking the two parts together, and the shear pin prevents the slide member from moving. After the two parts are locked together, one part of the cord is squeezed between the upper surface of the sliding member and one wall of the housing and the other part of the cord is squeezed between the lower surface of the sliding member and the other wall of the housing, so that the cord can no longer slide. After locking, the sliding cutting element may be actuated to cut away a portion of the cord that is proximal with respect to the two locked portions.)

1. An apparatus for securing a cord that has been secured around a loop, the apparatus comprising:

a housing having an upper wall and a lower wall with a channel disposed therebetween, the channel having a distal end;

a slide member in an initial position relative to the housing, a portion of the slide member disposed within the channel, the slide member having an upper surface and a lower surface, wherein the slide member has an opening extending between the upper surface and the lower surface, the opening having a distal end, and wherein: (a) at least a portion of the opening extends distally beyond the distal end of the channel, and (b) at least a portion of the opening is shaped and dimensioned to slidably receive the cord; and

a first shear pin arranged to hold the sliding member in the initial position until the first shear pin is sheared by a force exceeding a first threshold,

wherein the sliding member and the housing are configured such that: (a) after shearing the first shear pin, the sliding member will slide freely in a proximal direction relative to the housing until the sliding member reaches a final position; and (b) upon reaching the final position, the sliding member will be fixed at the final position, and

wherein the sliding member and the housing are further configured such that when the cord is passed through the opening in the sliding member before the first shear pin is sheared and the sliding member is subsequently moved to the final position, the distal end of the opening will enter the passage and urge a first portion of the cord to a position where the first portion of the cord will be compressed between the upper surface of the sliding member and the upper wall of the housing, and will also urge a second portion of the cord to a position where the second portion of the cord will be compressed between the lower surface of the sliding member and the lower wall of the housing.

2. The apparatus of claim 1, wherein the sliding member and the housing are shaped and dimensioned such that when a portion of the cord remaining outside the housing is pulled with a force of 7N, compression of the first and second portions of the cord will be sufficient to hold the cord in place.

3. The apparatus as set forth in claim 1, wherein,

wherein the housing has a first interior side wall and a second interior side wall defining a width of the channel,

wherein the sliding member has a T-shaped distal end disposed distally beyond the opening,

wherein the width of the T-shaped distal end is greater than the width of the channel, an

Wherein the sliding member has a plurality of spring arms, each of the plurality of spring arms having a distal end, wherein each of the plurality of spring arms is configured to: (a) such that a distal end of each of the plurality of spring arms is disposed within the channel when the slide member is in the initial position, and (b) such that when the slide member is moved to the final position, the distal end of each of the plurality of spring arms will exit the channel and automatically move to a position where a width between outermost portions of the plurality of spring arms exceeds a width of the channel.

4. The apparatus as set forth in claim 1, wherein,

wherein the sliding member has at least one protrusion disposed distally beyond the opening, wherein the at least one protrusion is shaped and positioned to inhibit proximal movement of the sliding member beyond the final position,

wherein the sliding member has at least one spring arm having a distal end, wherein the at least one spring arm is configured to: (a) such that when the slide member is in the initial position, the distal end of the at least one spring arm is disposed within and held in a compressed state by the channel, and (b) such that when the slide member is moved to the final position, the distal end of the at least one spring arm will exit the channel and automatically move to an expanded state, and

wherein when the slide member has been moved to the final position and the at least one spring arm is in the expanded state, the at least one spring arm inhibits distal movement of the slide member relative to the final position.

5. The apparatus of claim 1, wherein the first shear pin has a first end welded to the housing and a second end welded to the sliding member.

6. The apparatus of claim 1, the apparatus further comprising:

a second member arranged such that a pulling force in a proximal direction can be applied to the second member while the sliding member is held at a fixed position; and

a second shear pin arranged to: (a) the second shear pin maintains a connection between the second member and the sliding member as long as the pulling force remains below a second threshold; and (b) the second shear pin is sheared when the pulling force exceeds the second threshold, wherein the second threshold is at least twice the first threshold,

wherein the second member and the sliding member are configured such that shearing of the second shear pin will disconnect the second member from the sliding member.

7. The apparatus of claim 6, wherein the first threshold is between 5N and 10N, and wherein the second threshold is between 20N and 80N.

8. The apparatus of claim 1, wherein the upper wall of the housing, the lower wall of the housing, the upper surface of the sliding member, and the lower surface of the sliding member are all parallel.

9. The apparatus of claim 1, wherein the sliding member and the housing are further configured such that: (a) the entire opening distally beyond the distal end of the channel when the sliding member is in the initial position, and (b) the entire opening will be disposed within the channel after the sliding member has been moved to the final position.

10. The apparatus as set forth in claim 9, wherein,

wherein the lower wall of the housing extends distally beyond a distal end of the channel, and

wherein the lower wall of the housing has an opening, (a) the opening of the lower wall is aligned with the opening in the sliding member when the sliding member is in the initial position, and (b) the opening of the lower wall is sized such that the cord is slidable relative to both the opening in the lower wall of the housing and the opening in the sliding member when the sliding member is in the initial position.

11. An apparatus for securing a cord that has been secured around a loop, the apparatus comprising:

a housing having an upper wall and a lower wall with a channel disposed therebetween, the channel having a distal end;

a sliding member in an initial position relative to the housing, a portion of the sliding member disposed within the channel, the sliding member having an upper surface and a lower surface, wherein the sliding member has an opening extending between the upper surface and the lower surface, the opening having a distal end, and wherein the area is at least 0.4mm²At least a portion of the opening of (a) extends distally beyond the distal end of the channel; and

a first shear pin arranged to hold the sliding member in the initial position until the first shear pin is sheared by a force exceeding a first threshold,

wherein the sliding member and the housing are configured such that: (a) after shearing the first shear pin, the sliding member will slide freely in a proximal direction relative to the housing until the sliding member reaches a final position, and (b) upon reaching the final position, the sliding member will be fixed at the final position, wherein the sliding member and the housing are shaped and dimensioned such that a distal end of the opening in the sliding member will be at least 0.1mm from a distal end of the channel in a proximal direction after the sliding member has moved to the final position, and

wherein the upper wall of the housing and the lower wall of the housing are spaced apart by a first distance, wherein the upper surface of the sliding member and the lower surface of the sliding member are spaced apart by a second distance, and wherein the first distance exceeds the second distance by between 40 μm and 140 μm.

12. The apparatus of claim 11, wherein the upper wall of the housing, the lower wall of the housing, the upper surface of the sliding member, and the lower surface of the sliding member are all parallel,

wherein the sliding member and the housing are further configured such that: (a) the entire opening distally beyond the distal end of the channel when the sliding member is in the initial position, and (b) the entire opening will be disposed within the channel after the sliding member has been moved to the final position,

wherein the lower wall of the housing extends distally beyond a distal end of the channel,

wherein the lower wall of the housing has an area of at least 0.4mm²The opening of the lower wall is aligned with the opening in the slide member when the slide member is in the initial position; and is

Wherein the first distance exceeds the second distance by between 80 μm and 120 μm.

13. The apparatus of claim 12, wherein the sliding member and the housing are configured such that a distal end of the opening in the sliding member will be at least 0.3mm from a distal end of the channel in a proximal direction after the sliding member has been moved to the final position.

14. The apparatus of claim 12, the apparatus further comprising:

a second member arranged such that a pulling force in a proximal direction can be applied to the second member while the sliding member is held at a fixed position; and

a second shear pin arranged to: (a) the second shear pin maintains a connection between the second member and the sliding member as long as the pulling force remains below a second threshold, and (b) the second shear pin is sheared when the pulling force exceeds the second threshold, wherein the second threshold is at least twice the first threshold, and

wherein the second member and the sliding member are configured such that shearing of the second shear pin will disconnect the second member from the sliding member.

15. The apparatus as set forth in claim 14, wherein,

wherein the housing has a first interior side wall and a second interior side wall defining a width of the channel,

wherein the sliding member has a T-shaped distal end disposed distally beyond the opening,

wherein the width of the T-shaped distal end is greater than the width of the channel, an

Wherein the sliding member has a plurality of spring arms, each of the plurality of spring arms having a distal end, wherein each of the plurality of spring arms is configured to: (a) such that a distal end of each of the plurality of spring arms is disposed within the channel when the slide member is in the initial position, and (b) such that when the slide member is moved to the final position, the distal end of each of the plurality of spring arms will exit the channel and automatically move to a position where a width between outermost portions of the plurality of spring arms exceeds a width of the channel.

16. An apparatus for securing a rope that has been secured around a loop, the rope having a nominal diameter D, the apparatus comprising:

a housing having an upper wall and a lower wall with a channel disposed therebetween, the channel having a distal end;

a slide member in an initial position relative to the housing, a portion of the slide member disposed within the channel, the slide member having an upper surface and a lower surface, wherein the slide member has an opening extending between the upper surface and the lower surface, the opening having a distal end, and wherein the area is at least 10 × D²At least a portion of the opening of (a) extends distallyBeyond the distal end of the channel; and

a first shear pin arranged to hold the sliding member at the initial position until the first shear pin is sheared by a force exceeding a first threshold,

wherein the sliding member and the housing are configured such that: (a) after shearing the first shear pin, the sliding member will slide freely in a proximal direction relative to the housing until the sliding member reaches a final position, and (b) upon reaching the final position, the sliding member will be fixed at the final position, wherein the sliding member and the housing are shaped and dimensioned such that a distal end of the opening in the sliding member will be at least 0.5 x D from a distal end of the channel in a proximal direction after the sliding member has been moved to the final position, and

wherein the upper wall of the housing and the lower wall of the housing are spaced apart by a first distance, wherein the upper surface of the sliding member and the lower surface of the sliding member are spaced apart by a second distance, and wherein the first distance exceeds the second distance by between 0.25 XD and 0.9 XD.

17. The apparatus of claim 16, wherein the upper wall of the housing, the lower wall of the housing, the upper surface of the sliding member, and the lower surface of the sliding member are all parallel,

wherein the sliding member and the housing are further configured such that: (a) the entire opening distally beyond the distal end of the channel when the sliding member is in the initial position, and (b) the entire opening will be disposed within the channel after the sliding member has been moved to the final position,

wherein the lower wall of the housing extends distally beyond a distal end of the channel,

wherein the lower wall of the housing has an area of at least 0.4mm²When the sliding member is located at the opening ofIn an initial position, the opening of the lower wall is aligned with the opening in the sliding member; and is

Wherein the first distance exceeds the second distance by between 0.3 XD and 0.5 XD.

18. The apparatus of claim 17, wherein the sliding member and the housing are configured such that a distal end of the opening in the sliding member will be at least 2 x D from a distal end of the channel in a proximal direction after the sliding member has been moved to the final position.

19. The apparatus of claim 17, the apparatus further comprising:

a second member arranged such that a pulling force in a proximal direction can be applied to the second member while the sliding member is held at a fixed position; and

a second shear pin arranged to: (a) said second shear pin maintaining a connection between said second member and said sliding member as long as said pulling force remains below a second threshold value, and (b) said second shear pin is sheared when said pulling force exceeds said second threshold value, wherein said second threshold value is at least twice said first threshold value,

wherein the second member and the sliding member are configured such that shearing of the second shear pin will disconnect the second member from the sliding member.

20. The apparatus as set forth in claim 19, wherein,

wherein the housing has a first interior side wall and a second interior side wall defining a width of the channel,

wherein the sliding member has a T-shaped distal end disposed distally beyond the opening,

wherein the width of the T-shaped distal end is greater than the width of the channel, an

Wherein the sliding member has a plurality of spring arms, each of the plurality of spring arms having a distal end, wherein each of the plurality of spring arms is configured to: (a) such that a distal end of each of the plurality of spring arms is disposed within the channel when the slide member is in the initial position, and (b) such that when the slide member is moved to the final position, the distal end of each of the plurality of spring arms will exit the channel and automatically move to a position where a width between outermost portions of the plurality of spring arms exceeds a width of the channel.

21. An apparatus for reducing the diameter of a rope that has been previously secured to a loop, the apparatus comprising:

a housing having a distal portion and a distal end;

a shelf located in the distal portion of the housing and extending in a distal-to-proximal direction, the shelf having an upper surface, a lower surface, and a shelf opening extending between the upper surface and the lower surface of the shelf;

a cutting element located above the shelf and arranged such that the cutting element is slidable relative to the shelf in the distal-to-proximal direction, the cutting element having a flat body with an upper surface, a lower surface, and an opening passing between the upper surface and the lower surface of the cutting element, the opening of the cutting element having: (a) a proximal portion sized such that two segments of the cord can freely slide through the proximal portion, and (b) a slit-shaped distal portion having sharp edges, wherein the slit-shaped distal portion is oriented in the distal-to-proximal direction; and

a fastener located at the distal end of the housing, the fastener having an opening, wherein the fastener is movable from a first state in which the cord is free to slide through the opening in the fastener to a second state in which the cord is locked in place.

22. The apparatus of claim 21, wherein the fastener, the shelf, and the cutting element are configured such that when the fastener is in the first state, the cord can pass through the opening in the fastener such that after the fastener is moved to the second state, the cord will be disposed in a pre-cut position in which the cord passes over a portion of the cutting element that distally exceeds the opening of the cutting element, then passes through the opening of the cutting element and through the opening in the shelf, and

wherein the cutting element is configured such that when the cord is arranged in the pre-cut position, movement of the cutting element in the proximal direction will cause the slit-shaped distal portion of the opening of the cutting element to move in the proximal direction until the slit-shaped distal portion reaches the cord and cuts the cord.

23. The apparatus of claim 21, further comprising a shaft extending in the distal-to-proximal direction, wherein the shaft is fixed to the cutting element such that pulling the shaft in a proximal direction pulls the cutting element in a proximal direction.

24. The apparatus of claim 21, wherein the upper surface of the shelf is aligned with the upper surface of the fastener such that the upper surface of the fastener extends a sliding platform provided by the shelf.

25. The apparatus of claim 24, wherein the cutting element is configured to slide over both a portion of the upper surface of the fastener and the shelf.

26. The apparatus of claim 25, wherein a distal end of the shelf has a notch and a proximal end of the fastener has a protrusion that mates with the notch in the distal end of the shelf.

27. The apparatus of claim 25, wherein a distal end of the shelf has a first alignment feature and a proximal end of the fastener has a second alignment feature that mates with the first alignment feature.

28. The apparatus of claim 21, wherein the opening of the cutting element tapers smoothly in a distal direction from the proximal portion of the opening of the cutting element toward the slit-shaped distal portion of the opening of the cutting element.

29. The apparatus of claim 21, wherein the slit-shaped distal portion is formed by laser cutting the body of the cutting element to form a first slit having a width of 20-30 μ ι η, followed by swaging edges of the first slit toward each other to reduce the width of the first slit.

30. A cutting blade, comprising:

a flat body having an upper surface, a lower surface, and an opening passing between the upper surface and the lower surface,

wherein the opening has: a proximal portion sized to allow two segments of a retraction cord to freely slide therethrough; and a slit-shaped distal portion which is sufficiently sharp and narrow to cut the retraction cord when the slit-shaped distal portion encounters the retraction cord and is pulled in a proximal direction against the retraction cord,

wherein the slit extends in a proximal-to-distal direction, and

wherein the opening tapers smoothly in a distal direction from the proximal portion towards the slit-shaped distal portion.

31. The cutting blade of claim 30, wherein the slit-shaped distal portion is formed by laser cutting the body to form a first slit having a width of 20 μ ι η to 30 μ ι η, followed by swaging edges of the first slit toward each other to reduce the width of the first slit.

Background

U.S. patent 9,517,130 and applications WO 2013/088327 and WO 2014/195786, each of which is incorporated herein by reference, describe various methods for securing a contraction cable to a heart valve annulus or another anatomical annulus and contracting the diameter of the cable. In particular, U.S. patent 9,517,130 explains that after the cord is contracted, the two sections of the cord are fastened together (e.g., using knots, fasteners, or adhesives) to prevent the loop from re-expanding. The cord may then be cut at a point proximal relative to the fastening point. However, prior art methods for securing and cutting cords are not optimal for a variety of reasons. For example, prior art methods that attempt to tie a knot near the loop are time consuming and labor intensive; the prior art crimp-based fasteners have to be relatively large in order to exert sufficient force on the cord to reliably prevent slippage; and prior art methods for cutting ropes are labor intensive.

Disclosure of Invention

One aspect of the invention relates to a first device for securing a cord that has been secured around a loop. The first device includes a housing having an upper wall and a lower wall with a channel disposed therebetween, the channel having a distal end. The first apparatus also includes a sliding member located at an initial position relative to the housing, a portion of the sliding member disposed within the channel, the sliding member having an upper surface and a lower surface. The slide member has an opening extending between the upper surface and the lower surface, the opening having a distal end. At least a portion of the opening: (a) extends distally beyond the distal end of the channel, and (b) is shaped and dimensioned to slidably receive the cord. The first apparatus further comprises a first shear pin arranged to hold the sliding member at an initial position until the first shear pin is sheared by a force exceeding a first threshold. The sliding member and the housing are configured such that: (a) after shearing the first shear pin, the sliding member will be free to slide in the proximal direction relative to the housing until the sliding member reaches the final position, and (b) upon reaching the final position, the sliding member will be fixed at the final position. The sliding member and the housing are further configured such that when the cord is passed through the opening in the sliding member before the first shear pin is sheared and the sliding member is subsequently moved to a final position, the distal end of the opening will enter the passage and urge the first portion of the cord to a position where the first portion of the cord will be compressed between the upper surface of the sliding member and the upper wall of the housing, and the distal end of the opening will also urge the second portion of the cord to a position where the second portion of the cord is compressed between the lower surface of the sliding member and the lower wall of the housing.

In some embodiments of the first apparatus, the sliding member and the housing are shaped and dimensioned such that when the portion of the cord remaining outside the housing is pulled with a force of 7N, the compression of the first and second portions of the cord will be sufficient to hold the cord in place.

In some embodiments of the first apparatus, the housing has first and second inner side walls defining a width of the channel; the slide member has a T-shaped distal end disposed distally beyond the opening; the width of the T-shaped distal end is greater than the width of the channel; the slide member has a plurality of spring arms, each of which has a distal end. Each of the spring arms is configured to: (a) such that a distal end of each of the spring arms is disposed within the channel when the slide member is in the initial position, and (b) such that when the slide member is moved to the final position, the distal end of each of the spring arms will exit the channel and automatically move to a position where a width between outermost portions of the plurality of spring arms exceeds a width of the channel.

In some embodiments of the first apparatus, the sliding member has at least one protrusion disposed distally beyond the opening; the at least one projection is shaped and positioned to inhibit proximal movement of the slide member beyond the final position; the slide member has at least one spring arm having a distal end; the at least one spring arm is configured to: (a) such that when the slide member is in the initial position, the distal end of the at least one spring arm is disposed within and held in a compressed state by the channel, and (b) such that when the slide member is moved to the final position, the distal end of the at least one spring arm will exit the channel and automatically move to an expanded state; and the at least one spring arm inhibits distal movement of the slide member relative to the final position when the slide member has been moved to the final position and the at least one spring arm is in the expanded state.

In some embodiments of the first apparatus, the first shear pin has a first end welded to the housing and a second end welded to the sliding member.

Some embodiments of the first apparatus further comprise: a second member arranged such that a pulling force can be applied to the second member in a proximal direction when the sliding member is held at the fixed position; and a second shear pin arranged to: (a) maintaining the connection between the second member and the sliding member as long as the pulling force remains below a second threshold, and (b) shearing when the pulling force exceeds the second threshold, wherein the second threshold is at least twice the first threshold. In these embodiments, the second member and the sliding member are configured such that shearing of the second shear pin will disconnect the second member from the sliding member. Optionally, in these embodiments, the first threshold may be between 5N and 10N, and the second threshold may be between 20N and 80N.

In some embodiments of the first apparatus, the upper wall of the housing, the lower wall of the housing, the upper surface of the sliding member, and the lower surface of the sliding member are all parallel.

In some embodiments of the first apparatus, the sliding member and the housing are further configured such that: (a) the entire opening distally beyond the distal end of the channel when the sliding member is at the initial position, and (b) the entire opening will be disposed within the channel after the sliding member has been moved to the final position. In some of these embodiments, the lower wall of the housing extends distally beyond the distal end of the channel, the lower wall of the housing having an opening that: (a) aligned with the opening in the sliding member when the sliding member is at the initial position, the opening (b) being shaped and (c) sized such that the cord can slide relative to both the opening in the lower wall of the housing and the opening in the sliding member when the sliding member is at the initial position.

Another aspect of the invention relates to a second device for securing a cord that has been secured around a loop. The second device includes a housing having an upper wall and a lower wall with a channel disposed therebetween, the channel having a distal end. The second apparatus also includes a slide member located at an initial position relative to the housing, a portion of the slide member disposed within the channel, the slide member having an upper surface and a lower surface. The slide member has an opening extending between the upper surface and the lower surface, the opening having a distal end. Area of at least 0.4mm²At least a portion of the opening of (a) extends distally beyond the distal end of the channel. The second apparatus further comprises a first shear pin arranged to hold the sliding member at an initial position until the first shear pin is sheared by a force exceeding a first threshold. The sliding member and the housing are configured such that: (a) after shearing the first shear pin, the sliding member will be free to slide in the proximal direction relative to the housing until the sliding member reaches the final position, and (b) upon reaching the final position, the sliding member will be fixed at the final position. The slide member and the housing are shaped and dimensioned such that the distal end of the opening in the slide member will be at least 0.1mm from the distal end of the channel in the proximal direction after the slide member has been moved to the final position. The upper wall of the housing and the lower wall of the housing are spaced apart by a first distance, and the upper surface of the sliding member and the lower surface of the sliding member are spaced apart by a second distance, the first distance exceeding the second distance being between 40 μm and 140 μm.

In some embodiments of the second apparatus, the upper wall of the housing, the lower wall of the housing, the upper surface of the sliding member, and the lower surface of the sliding member are all parallel; the sliding member and the housing are further configured such that: (a)) The entire opening distally beyond the distal end of the channel when the sliding member is at the initial position, and (b) the entire opening will be disposed within the channel after the sliding member has been moved to the final position; the lower wall of the housing extends distally beyond the distal end of the channel; the lower wall of the housing has an opening with an area of at least 0.4mm²The opening is aligned with the opening in the slide member when the slide member is at the initial position; the first distance exceeds the second distance by between 80 μm and 120 μm. In some of these embodiments, the slide member and the housing are configured such that a distal end of the opening in the slide member is at least 0.3mm from the distal end of the channel in the proximal direction after the slide member has been moved to the final position.

Optionally, the embodiment described in the preceding paragraph may further include: a second member arranged such that a pulling force in a proximal direction can be applied to the second member while holding the sliding member at the fixed position; and a second shear pin arranged to: (a) maintaining the connection between the second member and the sliding member as long as the pulling force remains below the second threshold, and (b) being sheared when the pulling force exceeds the second threshold. The second threshold is at least twice the first threshold. In these embodiments, the second member and the sliding member are configured such that shearing of the second shear pin will disconnect the second member from the sliding member.

Optionally, in an embodiment described in the preceding paragraph, the housing has first and second inner side walls defining a width of the channel; the slide member has a T-shaped distal end disposed distally beyond the opening; the width of the T-shaped distal end is greater than the width of the channel; the slide member has a plurality of spring arms, each of the spring arms having a distal end. Each of the spring arms is configured to: (a) such that a distal end of each of the spring arms is disposed within the channel when the slide member is in the initial position, and (b) such that, when the slide member is moved to the final position, the distal end of each of the spring arms will exit the channel and automatically move to a position where a width between outermost portions of the plurality of spring arms exceeds a width of the channel.

Hair brushAnother aspect of the disclosure relates to a third device for securing a cord having a nominal diameter D that has been secured around a loop, the third device including a housing having an upper wall and a lower wall with a channel disposed therebetween, the channel having a distal end, the third device further including a sliding member located at an initial position relative to the housing, a portion of the sliding member disposed within the channel, the sliding member having an upper surface and a lower surface, the sliding member having an opening extending between the upper surface and the lower surface, the opening having a distal end, and an area of at least 10 × D²The sliding member and the housing are configured and dimensioned such that, after the sliding member has been moved to the final position, a distal end of the opening in the sliding member will be at least 0.5 × D in the proximal direction from the distal end of the passage, an upper wall of the housing and a lower wall of the housing are spaced a first distance, an upper surface of the sliding member and a lower surface of the sliding member are spaced a second distance, the first distance exceeding the second distance between 0.25 × D and 0. 0.9 × D.

In some embodiments of the third apparatus, the upper wall of the housing, the lower wall of the housing, the upper surface of the sliding member, and the lower surface of the sliding member are all parallel; the sliding member and the housing are further configured such that: (a) the entire opening distally beyond the distal end of the channel when the sliding member is at the initial position, and (b) the entire opening will be disposed within the channel when the sliding member has been moved to the final position; the lower wall of the housing extends distally beyond the distal end of the channel; the lower wall of the housing has an opening with an area of at least 0.4mm²The opening is aligned with the opening in the slide member when the slide member is at the initial position; first of allThe distance exceeds the second distance by between 0.3 × D and 0.5 × D.

In some of the embodiments described in the preceding paragraph, the slide member and the housing are configured such that the distal end of the opening in the slide member will be at least 2 x D from the distal end of the channel in the proximal direction after the slide member has been moved to the final position. Some of the embodiments described in the preceding paragraphs further include: a second member arranged such that a pulling force in a proximal direction can be applied to the second member while holding the sliding member at the fixed position; and a second shear pin arranged to: (a) maintaining the connection between the second member and the sliding member as long as the pulling force remains below the second threshold, and (b) shearing when the pulling force exceeds the second threshold. The second threshold is at least twice the first threshold. In these embodiments, the second member and the sliding member are configured such that shearing of the second shear pin will disconnect the second member from the sliding member. Optionally, in these embodiments, the housing has first and second inner side walls defining a width of the channel; the slide member has a T-shaped distal end disposed distally beyond the opening; the width of the T-shaped distal end is greater than the width of the channel; the slide member has a plurality of spring arms, each of the spring arms having a distal end. Each of the spring arms is configured to: (a) such that a distal end of each of the spring arms is disposed within the channel when the slide member is in the initial position, and (b) such that, when the slide member is moved to the final position, the distal end of each of the spring arms will exit the channel and automatically move to a position where a width between outermost portions of the plurality of spring arms exceeds a width of the channel.

Another aspect of the invention relates to a fourth apparatus for reducing the diameter of a rope that has been previously secured to a loop. The fourth device includes a housing having a distal portion and a distal end. The fourth apparatus also includes a shelf in the distal portion of the housing extending in a distal-to-proximal direction, the shelf having an upper surface, a lower surface, and a shelf opening extending between the upper surface and the lower surface of the shelf. The fourth apparatus further comprises a cutting element positioned above the shelf and arranged such that the cutting element can slide relative to the shelf in a distal to proximal direction, the cutting element having a flat body with an upper surface, a lower surface, and an opening passing between the upper and lower surfaces of the cutting element, the opening of the cutting element having: (a) a proximal portion sized such that two segments of the cord can freely slide through the proximal portion, and (b) a slit-shaped distal portion having sharp edges, wherein the slit-shaped distal portion is oriented in a distal-to-proximal direction. The fourth device also includes a fastener at the distal end of the housing, the fastener having an opening. The fastener is movable from a first state in which the cord is free to slide through the opening in the fastener to a second state in which the cord is locked in place.

In some embodiments of the fourth apparatus, the fastener, the shelf, and the cutting element are configured such that when the fastener is in the first state, the cord can pass through the opening in the fastener such that after the fastener is moved to the second state, the cord will be disposed in a pre-cut position in which the cord passes over a portion of the cutting element that is distally beyond the opening of the cutting element, then through the opening of the cutting element and through the opening in the shelf. In these embodiments, the cutting element is configured such that when the cord is arranged in the pre-cutting position, a movement of the cutting element in the proximal direction will cause the slit-shaped distal portion of the opening of the cutting element to move in the proximal direction until the slit-shaped distal portion reaches the cord and cuts the cord.

Some embodiments of the fourth apparatus further comprise a shaft extending in a distal-to-proximal direction. The shaft is fixed to the cutting element such that pulling the shaft in the proximal direction will pull the cutting element in the proximal direction.

In some embodiments of the fourth apparatus, an upper surface of the shelf is aligned with an upper surface of the fastener such that the upper surface of the fastener extends a sliding platform provided by the shelf. In some of these embodiments, the cutting element is configured to slide over both a portion of the upper surface of the fastener and the shelf. In some of these embodiments, the distal end of the shelf has a first alignment feature (e.g., a notch) and the proximal end of the fastener has a second alignment feature (e.g., a protrusion) that mates with the first alignment feature.

In some embodiments of the fourth apparatus, the opening of the cutting element tapers smoothly in a distal direction from a proximal portion of the opening of the cutting element towards a slit-shaped distal portion of the opening of the cutting element.

In some embodiments of the fourth apparatus, the slit-shaped distal portion is formed by laser cutting the body of the cutting element to form a first slit having a width of 20 μm to 30 μm, and then swaging (swaging) edges of the first slit toward each other to reduce the width of the first slit.

Another aspect of the invention relates to the fifth apparatus. A fifth device is a cutting blade that includes a flat body having an upper surface, a lower surface, and an opening therethrough between the upper surface and the lower surface. The opening has: a proximal portion sized to allow two segments of a retraction cord to freely slide through the proximal portion; and a slit-shaped distal portion that is sufficiently sharp and narrow to cut the retraction cords when the slit-shaped distal portion encounters the retraction cords and resists being pulled in a proximal direction. The slit extends in a proximal to distal direction, and the opening tapers smoothly in the distal direction from the proximal portion towards the slit-shaped distal portion.

In some embodiments of the fifth apparatus, the slit-shaped distal portion is formed by laser cutting the body to form a first slit having a width of 20 μm to 30 μm, and subsequently swaging edges of the first slit towards each other to reduce the width of the first slit.

Drawings

Fig. 1A shows a fastener for fastening portions of a shrink rope together. The fastener includes a housing and a sliding member.

Fig. 1B shows a side view of the housing from a position distally beyond the distal end of the housing.

Figure 2 shows the slide member and housing at a particular alignment point.

Fig. 3A and 3B show top and bottom views, respectively, of a fastener at the same alignment point, with a wire passing through a pair of holes.

Fig. 4A and 4B show top and bottom views, respectively, of the fastener after the wire has been welded to the housing and the sliding member.

Fig. 5 shows a second member to which a second wire is welded.

Fig. 6 shows a second wire passing through a hole in the sliding member.

Fig. 7A and 7B show an upper view and a lower view, respectively, of the fastener after the fastener has been connected to the second member.

FIG. 7C shows a plan view and a cross-sectional view of the fastener after the fastener has been connected to the second member.

Fig. 8 shows a subassembly that includes a fastener that is loaded into the distal end of the tool and threaded onto the retraction cord.

Fig. 9 shows the tool after it has been advanced until the subassembly reaches the distal loop portion of the retraction cord.

Fig. 10 shows the tool after it has been used to reduce the diameter of the distal loop portion of the retraction cord.

Fig. 11 is a detail of fig. 10.

Fig. 12 shows the fastener in its initial state.

Fig. 13 shows the fastener after shearing the first shear pin and after the sliding member has begun to slide in a proximal direction relative to the housing.

Fig. 14 shows the fastener after further sliding in the proximal direction.

Fig. 15 shows the fastener after shearing the second shear pin and after the sliding member has begun to slide further in the proximal direction relative to the housing.

Fig. 16 shows the fastener after further sliding in the proximal direction.

Fig. 17A illustrates the path of the retraction cord through the opening in the slide member when the slide member is in the initial position.

Fig. 17B is similar to fig. 17A, but shows an additional feature of the path of the retraction cord.

Fig. 17C shows a side sectional detail of fig. 17A.

Fig. 18A shows the path of the retraction cord through the housing and the opening in the slide member after the slide member has been moved to the final position.

Fig. 18B is similar to fig. 18A, but shows additional features of the path of the retraction cord.

Fig. 18C is a detailed view of fig. 18B.

Fig. 18D depicts a side cross-sectional detail of fig. 18A.

Fig. 19 shows the fastener and cord in the same state as in fig. 18A-18D, with the addition of additional components disposed at the distal end of the tool.

Fig. 20 is a cross-sectional view of the tool, revealing additional details of the interrelationship between the cutting blade and the proximal portion of the cord.

Fig. 21 shows the assembly shown in fig. 20 after the second member has been pulled in a radial direction away from the sliding member.

Fig. 22 shows the next step in the sequence immediately prior to cutting the proximal portion of the cord.

Fig. 23 shows the next step in the sequence after the blade has moved in the proximal direction and cut the proximal portion of the tether.

Fig. 24A and 24B illustrate withdrawal of the tool in the proximal direction.

Figure 25 shows the components left in the patient after withdrawal of the tool.

Fig. 26A and 26B show upper and lower views of the cutting blade, respectively.

Fig. 27A and 27B show detail views of the lower surface of the cutting blade before and after swaging the part, respectively.

Various embodiments are described in detail below with reference to the drawings, wherein like reference numerals represent like elements.

Detailed Description

As explained in us patent 9,517,130, which is incorporated herein by reference, an implant comprising a distal ring portion of a contraction cord may be secured to the annulus of a heart valve or another anatomical ring. After a sufficiently strong bond between the implant and the loop is achieved, the diameter of the loop will be reduced by contracting the cord. Some preferred embodiments of the implant rely on tissue ingrowth to enhance the bond between the implant and the ring. In these embodiments, the contracting step is not performed immediately after the implant is implanted. Rather, a considerable waiting time (e.g., 1-3 months) passes between the implantation step and the contraction step in order for sufficient time for ingrowth to occur. During this waiting time, tissue ingrowth of adjacent soft tissue into the implant enhances the bond between the implant and the ring. Once the tissue ingrowth process has sufficiently enhanced the bond (i.e., to the extent that it withstands contraction with sufficient confidence), the contraction ropes are contracted to reduce the diameter of the annulus. In other embodiments, the attachment mechanism of the implant may be strong enough to undergo contraction immediately after the implant is implanted, in which case the contraction cord may be contracted immediately after the implant is implanted.

Two proximal portions (or segments) of the contraction rope extend from outside the patient's body to the implanted distal ring portion of the contraction rope. As explained in us patent 9,517,130, the contraction of the contraction cord may be performed by sliding the push tube down on the proximal portion of the contraction cord until the distal end of the push tube reaches the distal loop portion of the contraction cord (i.e., the loop portion that has been secured to the loop). Since the proximal portions of the retraction cords extend through the patient's vasculature between the retraction implant and the exit point, these proximal portions can serve as guide wires over which the push tube can be guided to its destination. When the push tube reaches the distal loop portion of the retraction cord and is pushed in the distal direction, pulling the proximal portion of the retraction cord in the proximal direction will retract the loop, thereby reducing the circumference of the loop. The distal ends of the proximal portions of the retraction cords are then secured together to prevent the loop from re-expanding. The proximal portion of the retraction cord may then be clamped at a location proximal to where they are secured together.

The remainder of the application describes various methods for securing the distal ends of the proximal portions of the retraction cords together.

Fig. 1A shows two primary components of a fastener 100/200 that may be used to fasten together the distal ends of the proximal portions of the retraction cords. More particularly, the two main components of the fastener are the housing 100 and the sliding member 200. Fig. 1B shows a side view of the housing 100 as viewed from a point distally beyond the distal end of the housing 100. The housing has an upper wall 102 and a lower wall 104 with a channel 110 disposed between the upper wall 102 and the lower wall 104. The channel 110 has a distal end 112. In the embodiment shown, both the upper wall 102 and the lower wall 104 are flat and parallel to each other; the housing also has side walls 106 that extend between the upper wall 102 and the lower wall 104 to form a rigid structure. In the illustrated embodiment, the sidewalls 106 are also flat and parallel to each other. And in the illustrated embodiment, the extension 104X of the lower wall 104 extends distally beyond the distal end of the channel 112. The extension 104X has an opening 120. In some preferred embodiments, the opening 120 has an area of at least 0.4mm². In an alternative embodiment, the opening 120 has an area of 0.3mm²To 1.0mm²In the meantime. Suitable materials for forming the housing 100 include cobalt chrome (including but not limited to MP35N, L605, Elgiloy, etc.), surgical stainless steel (including but not limited to 305ss, 316ss, etc.), and other biocompatible metals. In some preferred embodiments, the housing 100 is sized such that the channel 110 is 1.5mm long (in the proximal-to-distal direction), 1.8mm wide, and 0.64mm high; and such that extension 104X extends distally 1.5mm beyond the distal end of channel 112.

The slide member 200 has an upper surface 202 and a lower surface 204 (as shown in fig. 3B), and the slide member 200 has an opening 220 extending between the upper surface 202 and the lower surface 204. In some preferred embodiments, the opening 220 has an area of at least 0.4mm². In an alternative embodiment, the opening 220 has an area of 0.3mm²To 1.0mm²In the meantime.The opening 220 has a distal end. Preferably, the edges of the channel 110 of the housing and the edges of the opening 220 of the sliding member are not sharp to reduce the chance of damaging the cord. Suitable materials for forming the sliding member 200 include any of the materials listed above with respect to the housing 100. In some preferred embodiments, the sliding member 200 is 4.6mm long (in the proximal-to-distal direction), 0.53mm high, 1.8mm wide; the distal end of the sliding member 200 (which prevents the sliding member 200 from entering the channel 110 in the housing) is 2.3mm wide. Of course, if any dimension of the housing 100 deviates from the dimensions specified above, the dimensions of the sliding member 200 should be modified accordingly to maintain the interaction between these two components described herein.

Fig. 2-7 illustrate one preferred method for assembling a subassembly that holds the slide member 200 in an initial position relative to the housing 100 prior to deploying the fasteners.

As shown in fig. 1A, the lower wall 104 of the housing 100 has a through hole 108, and the slide member has a through hole 208. In some preferred embodiments, the diameter of the through holes is between 0.1mm and 0.4mm, and in some preferred embodiments the diameter of the through holes is about 0.15 mm. The sliding member 200 and the housing 100 are configured relative to each other such that prior to assembly of the subassembly, the sliding member 200 is free to slide in a proximal direction relative to the housing 100 until the through-hole 108 of the housing is aligned with the through-hole 208 of the sliding member, as shown in fig. 2. At this point, the wire 308 passes through the through holes 108, 208 as depicted in fig. 3A and 3B, which are top and bottom views, respectively. Suitable materials for the wire 308 include any of the materials listed above with respect to the housing 100, with suitable diameters for the wire 308 ranging from 0.075mm to 0.4 mm. In some preferred embodiments, the diameter of wire 308 is 0.13 mm.

Note that when the housing 100 and the slide member 200 are aligned at this position, the opening 120 of the housing will be aligned with the opening 220 of the slide member, as shown in fig. 3A and 3B.

Then, the upper end of the wire 308 is welded to the upper surface 202 of the sliding member 200 at a welding point 309 (as shown in fig. 4A); the lower end of wire 308 is welded to the bottom of housing 100 at weld 309 (as shown in fig. 4B). By welding the upper and lower ends of the wire 308 to the upper surface 202 of the sliding member 200 and the bottom of the housing 100, respectively, a first shear pin 310 is formed (as shown in fig. 7C) that holds the sliding member 200 in a fixed position (referred to herein as an "initial position") relative to the housing 100 until the first shear pin 310 is sheared by a force that exceeds a first threshold. In some embodiments, the first threshold is between 5N and 10N. Note that while welding is the preferred method for forming the first shear pin 310, alternative methods apparent to those skilled in the relevant art may also be used to form the shear pin 310 that holds the sliding member 200 in a fixed position relative to the housing 100.

Second member 420 is then positioned adjacent the proximal end of slide member 200, and second shear pin 320 (shown in FIG. 7C) is secured between second member 420 and slide member 200. One method for forming the second shear pin 320 is illustrated in fig. 5-7. In fig. 5, the lower end of the second wire 318 is welded to the second member 420 at a weld 319. Subsequently, the upper end of the second wire 318 passes through the hole 218 (shown in fig. 1) in the sliding member 200, as shown in fig. 6. Then, the upper end of the second wire is welded to the slide member 200 at a welding point 319, as shown in fig. 7A. Fig. 7B is a bottom view of the subassembly at this point, and fig. 7C depicts a plan view and a cross-sectional view of the subassembly at this point. Suitable materials for both the second member 420 and the second wire 318 include any of the materials listed above with respect to the housing 100, with a suitable diameter for the second wire 318 in the range of 0.1mm to 0.4 mm. In some preferred embodiments (e.g., those in which the diameter of the first wire 308 is 0.13 mm), the diameter of the second wire 318 is 0.28 mm. As will be appreciated by those skilled in the relevant art, any change in the size of the first wire 308 should be accompanied by a corresponding change in the size of the second wire 318 to ensure that the first shear pin 310 will always be sheared before the second shear pin 320.

As long as the pulling force acting on second shear pin 320 in the proximal direction remains below the second threshold (while sliding member 200 is held at a fixed position), second shear pin 320 maintains the connection between second member 420 and sliding member 200. Additionally, the second shear pin 320 is configured to shear when the pulling force exceeds a second threshold. Shearing of the second shear pin will disconnect the second member 420 from the sliding member 200. In some preferred embodiments, the second threshold is at least twice the first threshold. In some embodiments, the second threshold is between 20N and 80N. A shaft 422 (shown in fig. 5 and 6) is secured to the second member 420 and is used to apply a pulling force to the second member 420 in a proximal direction. Suitable materials for the shaft 422 include any of the materials listed above with respect to the housing 100.

The two shear pins 310, 320 are clearly visible in the cross-sectional view of fig. 7C. More particularly, the first shear pin 310 retains the sliding member 200 at its fixed initial position relative to the housing 100 until the first shear pin 310 is sheared (as described below in connection with fig. 12-14); the second shear pin 320 connects the sliding member 200 to the second member 420 until the second shear pin 320 is sheared by a force that exceeds a second threshold (as described below in connection with fig. 14-16). Note that while welding is the preferred method for forming second shear pin 320, alternative methods, as will be apparent to those skilled in the relevant art, may also be used to form shear pin 320 that holds slide member 200 in a fixed position relative to second member 420. Note that when using the configuration shown in fig. 7A-7C, the shaft 422 may be used to hold the entire subassembly 100 and 422 in place relative to the tool 400 described below in connection with fig. 8-10.

In some alternative embodiments (not shown), instead of securing the shaft 422 to the second member 420 and connecting the second member 420 to the slide member 200 using the shear pin 320 (as described above in connection with fig. 7A-7C), the pull shaft 422 may be connected directly to the proximal end of the slide member 200 (e.g., by welding). In these embodiments, the weakened area is preferably designed into the distal end of the pulling shaft 422 such that when a pulling force applied to the pulling shaft 422 exceeds a threshold value, the pulling shaft 422 will break at the weakened area. One way to create this weakened region is to use thermal effects to change the properties of the metal pulling shaft 422. Alternatively, a single welding step may be used to both attach the shaft 422 to the sliding member 200 and introduce thermal effects into the distal portion of the shaft 422.

Fig. 8-21 illustrate how the subassembly 100-422 (shown in fig. 7A-7C) may be used to shrink the diameter of the ring. Turning first to fig. 8, subassembly 100-422 is loaded into the distal end of tool 400. As explained above, the proximal portions 520 of the retraction cords 500 are passed through the patient's vasculature between the distal ring portions 510 of the retraction cords 500 and the exit point so that these proximal portions can serve as guide wires through which the push tube can be guided to its destination. The body of the tool 400 serves as the push tube. Portions of the retraction cord 500 beyond the exit point pass through the openings 120, 220 of the subassembly 100 and 422 (e.g., using pre-installed guide wires, not shown) such that those portions of the cord follow the path depicted in fig. 8. The tool 400 is then advanced in the distal direction until the subassembly 100 and 422 reach the vicinity of the annulus, as shown in FIG. 8. Alternatively, the shaft of the tool 400 may include a steerable segment, such as a steerable segment implemented using any of a variety of steerable catheter mechanisms well known to those skilled in the relevant art.

The tool 400 is then further advanced in the distal direction until the subassembly 100 and 422 reach the distal loop portion 510 of the retraction cord that has been previously secured to the loops, as shown in FIG. 9.

After the subassembly 100-422 reaches this position, the distal loop portion 510 of the retraction cord is retracted by pulling on the proximal end of the retraction cord 520 while the tool 400 holds the subassembly 100-422 in place. This constriction is illustrated in fig. 10 (which shows how the diameter of the distal loop portion 510 of the retraction cord decreases when the proximal portion 520 of the retraction cord is pulled in the proximal direction by the tool 400) and fig. 11 (which is a detail of fig. 10). And because the distal loop portion 510 of the retraction cord is secured to the loop, the diameter of the loop will also decrease.

During the contraction of the rope 500 there will be a significant tension on the rope. This tension pulls the region of the distal loop portion 510 of the cord on either side of the opening 120 in the housing 100 and the opening 220 in the sliding member 200 away from each other (limited by the boundaries of the openings 120 and 220). As a result, if the proximal portion 520 twists near the interface with the distal ring portion 510 when the subassembly 100 reaches the ring, the tension will cause these twists to move in a proximal direction along the proximal portion 520 of the cord until they move proximally beyond the area that will eventually be clamped together (as described below in connection with fig. 17-18). This is advantageous as it improves the repeatability and reliability of the clamp fastening process.

Note that while pulling the proximal end of the retraction cord 520 in the proximal direction, it is important for the tool 400 to hold the subassembly 100 and 422 in place. This may be accomplished, for example, by applying a force in a distal direction on the body of the tool 400 such that the distal end 410 of the tool transmits the force to the portion of the housing 100 of the sub-assembly 100 and 422 such that the sub-assembly 100 and 422 will remain in place while the proximal end of the retraction cord 520 is pulled (as best shown in fig. 11).

After the diameter of the loop has been contracted as described above, tension is maintained on the proximal end of the contraction cable 520, and a force is applied in the distal direction to the housing 100 by the tool 400 until deployment of the fastener 100/200 is complete (as described below in connection with fig. 12-21).

Fig. 12 shows fastener 100/200 in its initial state, which is the same as the initial state depicted in fig. 7C. In this initial state, both shear pins 310, 320 are intact. While the housing 100 is held in place by the tool 400, a pulling force in a proximal direction is applied to the shaft 422, for example using any suitable mechanism (not shown) disposed at the proximal end of the tool 400. The shaft 422 transmits the tensile force to the second member 420. Because the second shear pin 320 is still intact in this sequence at this time, the pulling force applied to the shaft 422 will be transferred to the sliding member 200.

The first shear pin 310 retains the sliding member 200 in this initial position relative to the housing 100 as long as the pulling force applied to the shaft 422 remains below the threshold force for shearing the first shear pin 310. However, once the pulling force exceeds the threshold for shearing the first shear pin 310, the shear pin 310 will be sheared and the sliding member will begin to slide in a proximal direction relative to the housing 100, as shown in fig. 13.

The pulling force remains acting on the shaft 422. Shear pin 320 continues to transmit this force to slide member 200. Because shear pin 310 has been sheared, sliding member 200 will continue to slide in the proximal direction relative to the housing until sliding member 200 reaches the position shown in fig. 14 relative to housing 100. This position of the slide member 200 is referred to herein as the "final position". The sliding member 200 cannot continue proximally beyond the final position because the distal end 240 of the sliding member 200 is too large to fit into the channel 110 in the housing. More particularly, as shown in FIG. 1A, the width of the channel 110 is defined by the first and second inner side walls 106. Also in the illustrated embodiment, the sliding member 200 has a T-shaped distal end 240 that has a width that is greater than the width of the channel 110.

In the illustrated embodiment, the slide member 200 also has a pair of spring arms 230 that were compressed together by the side wall 106 of the housing 100 prior to this point in the sequence, the distal end of each of the spring arms 230 being disposed within the channel 110. However, once the slide member 200 reaches the final position depicted in fig. 14, the slide member 200 will exit the proximal end of the channel 110 and automatically spring outward until the spring arm 230 reaches its relaxed state. In its relaxed state, the distance between the outermost portions of the two spring arms 230 will exceed the width of the channel 110 (as shown in fig. 1A and 1B), which prevents the sliding member 200 from sliding back in the distal direction relative to the housing 100.

Because the sliding member 200 cannot continue proximally beyond the final position (due to the distal end 240 of the sliding member 200) and cannot slide back in the distal direction (due to the operation of the spring arm 230), the sliding member 200 will be fixed at this position once the sliding member 200 reaches its final position. In alternative embodiments, when the sliding member 200 reaches the final position, different methods may be used to secure the sliding member 200, as will be apparent to those skilled in the relevant art. For example, instead of having a T-shaped distal end, a single protrusion may be disposed at the distal end of the sliding member 200, the single protrusion being shaped and positioned to inhibit proximal movement of the sliding member 200 beyond the final position. Similarly, instead of relying on a pair of spring arms 230 to prevent the slide member 200 from moving backwards in the distal direction from the final position, a single spring arm may be used to achieve the same result.

As long as the pulling force on shaft 422 remains below the second threshold (i.e., the threshold required to shear second shear pin 320), second shear pin 320 will prevent further movement of second member 420 in the proximal direction. The second member 420 is not part of the fastener that will remain behind and must be broken and removed. This is accomplished by increasing the pulling force on the shaft 422 to increase the corresponding pulling force exerted by the second member 420 on the second shear pin 320. When the pulling force exceeds a second threshold, the second shear pin 320 will be sheared and the second member 420 will begin to move in the proximal direction, as shown in fig. 15. Continued application of a pulling force on the shaft 422 will move the second member 420 further away from the slide member 200 (which is now locked to the housing 100 in the final position), as shown in fig. 16. Advantageously, the above-described design using two shear pins 310, 320 with different shear thresholds provides excellent consistency and repeatability, such that a repeatable level of force will shear each of those shear pins, and such that the first shear pin 310 will always be sheared before the second shear pin 320.

Note that after the second shear pin 320 is sheared and the second member 420 has been pulled away from the sliding member 200, the cord 500 (which is preferably held taut during this portion of the process, e.g., by pulling the proximal end of the proximal portion 520 of the cord 500 in a proximal direction) holds the fastener 100/200 at the distal end of the tool 400 until the cord 500 is cut by the cutting blade 450 (as described below in connection with fig. 22-23) or released.

Having explained the interaction between the slide member 200 and the housing 100 by reference to fig. 12-16, we return an explanation of how the slide member 200 and the housing 100 interact with the retraction cord 500 to secure the cord in its retracted state.

The retraction cord 500 is last referred to in this application in conjunction with fig. 10-11, where the proximal portion 520 of the retraction cord passes through the openings 120, 220 of the sub-assembly 100 and 422, and then the distal loop portion 510 of the retraction cord is retracted by pulling on the proximal end of the retraction cord while the tool 400 holds the sub-assembly 100 and 422 in place.

Fig. 17-18 explain how the fastener 100/200 is caused to lock the retraction cord in place by moving the sliding member 200 from its initial position to its final position (following the sequence described above in connection with fig. 12-16) after retracting the distal loop portion 510 of the retraction cord. In the sequence of this figure, the body of the tool 400 is omitted for clarity.

Fig. 17A shows the path of the retraction cords 510, 520 through the opening 220 in the slide member 200 when the slide member 200 is in the initial position (corresponding to the position shown in fig. 12 in the sequence described above). Fig. 17B is similar to fig. 17A, except that the portion of the retraction cord passing under the housing 100 and the slide member 200 is shown in phantom. Fig. 17C depicts a side sectional detail showing how the cords 510, 520 pass through the opening 120 in the housing 100 and through the opening 220 in the slide member 200 when the slide member 200 is in its initial position. At this point in the sequence, the first and second shear pins 310, 320 are still intact. Additionally, while the fastener 100/200 is held in place by the tool 400, the diameter of the distal loop portion 510 of the retraction cord can still be adjusted by gradually pulling the proximal portion of the retraction cord 520 in a proximal direction.

Fig. 18A shows the path of the retraction cords 510, 520 through the opening 120 in the housing 100 and the opening 220 in the slide member 200 after the slide member 200 has been moved to the final position (which corresponds to the position shown in fig. 16 in the sequence described above). Fig. 18B is similar to fig. 18A, except that the path of the retraction cord through the two openings is shown in phantom. Fig. 18C is a detail view of fig. 18B, and fig. 18D shows a side cross-sectional detail, showing how the cords 510, 520 pass through the opening 120 in the housing 100 and through the opening 220 in the slide member 200 when the slide member 200 is in its final position.

At this point in the sequence (as best shown in fig. 18C and 18D), the distal end of the opening 220 in the sliding member 200 has entered the channel (which is bounded by the upper and lower walls 102, 104 of the housing 100) and has pushed the first portion 522 of the cord to a position where the first portion 522 of the cord is compressed between the upper surface 202 of the sliding member 200 and the upper wall 102 of the housing 100, and has also pushed the second portion 524 of the cord to a position where the second portion 524 of the cord is compressed between the lower surface 204 of the sliding member 200 and the lower wall 104 of the housing 100. In some preferred embodiments, the sliding member 200 and the housing are shaped and sized such that when the portion of the cord remaining outside the housing is pulled with a force of 7N, the compression of the first portion 522 and the second portion 524 of the cord will be sufficient to hold the cord in place.

For example, assume that the nominal diameter of the rope 500 is 0.15 mm; the distal end of the opening 220 in the sliding member is 0.3mm from the distal end of the channel in the proximal direction; the gap between the upper wall 102 of the housing 100 and the upper surface 202 of the sliding member 200 is 50 μm; and the gap between the lower wall 104 of the housing 100 and the lower surface 204 of the sliding member 200 is also 50 μm. When these dimensions are used, the first portion 522 of the cord is compressed between the upper surface 202 of the sliding member 200 and the upper wall 102 of the housing 100, thereby reducing its original nominal diameter from 0.15mm to 50 μm. Similarly, the second portion 524 of the cord is compressed between the lower surface 204 of the sliding member 200 and the lower wall 104 of the housing 100, thereby reducing its original nominal diameter from 0.15mm to 50 μm. In this case, the compressive force applied to the two portions 522, 524 of the cord is sufficient to prevent the cord 500 from sliding relative to the fastener 100/200.

Note that in this example, the first distance between the upper wall of the housing and the lower wall of the housing will exceed the second distance between the upper surface of the slide member and the lower surface of the slide member by 100 μm (because a gap of 50 μm occurs both above and below the slide member). But in alternative embodiments the first distance will exceed the second distance by 40 μm to 140 μm, or the first distance will exceed the second distance by 80 μm to 120 μm. Also note that in this example, the distal end of the opening 220 in the sliding member is 0.3mm from the distal end of the channel in the proximal direction. However, in an alternative embodiment, the distal end of the opening 220 in the sliding member is at least 0.1mm from the distal end of the channel in the proximal direction.

When the nominal diameter of the rope is greater or less than 0.15mm, the various dimensions should be scaled up or down accordingly. For example, if the nominal diameter of the cord is D, the area of the opening 220 in the sliding member 200 should be D²At least 10 times higher; the distal end of the opening 220 in the sliding member 200 should be at least half the distance D from the distal end 112 of the channel in the proximal direction; and the first distance should exceed the second distance by 0.25 to 0.9 times D, or by 0.3 to half D.

Fig. 19 shows the fastener 100/200 and cords 510, 520 in the same state as fig. 18A-18D, but also shows additional components provided at the distal end of the tool 400 that are omitted from fig. 18A-18D for clarity. More particularly, fig. 19 depicts the distal end 410 of the tool 400 and a cutting blade 450 (also referred to herein as a cutting element) for cutting a proximal portion of the cord 520 after the fastener 100/200 has secured the cord to its reduced diameter state.

Fig. 20 is a cross-sectional view of tool 400, revealing additional details of the interrelationship between cutting blade 450 and the proximal portion of cord 520. More particularly, the cutting blade 450 has a flat body with an upper surface, a lower surface, and an opening 454 that passes between the upper and lower surfaces. The proximal portion of the cable 520 passes through the opening 454 above the distal end of the cutting blade 450 and continues in the proximal direction below the proximal end of the cutting blade 450. Shaft 460 is fixed to cutting blade 450 such that pulling shaft 460 in a proximal direction will pull cutting blade 450 in a proximal direction.

Fig. 21 shows the same assembly shown in fig. 20 at a point in time corresponding to fig. 16 (i.e., after second member 420 has been pulled away from sliding member 200 in a proximal direction).

Fig. 22 and 23 show subsequent steps in the sequence during which the proximal portion of the cord 520 is cut. The cutting blade 450 is slidably positioned on the shelf 470 such that the cutting blade 450 can slide in a distal-to-proximal direction relative to the shelf 470. The shelf 470 has upper and lower surfaces and a shelf opening or aperture 475 that extends between the upper and lower surfaces of the shelf 470. Cutting is accomplished by first ensuring that the proximal portion of the cord 520 is taut (e.g., by pulling the proximal end of the proximal portion 520 in a proximal direction while pushing the body 400 in a distal direction), and then pulling the proximal end of the shaft 460 in a proximal direction, such that the shaft 460 will pull the cutting blade 450 in a proximal direction. The interaction between the various components involved in cutting is described in more detail immediately below.

Fig. 22 shows the position of the relevant components just prior to cutting the proximal portion 520 of the cord. At this point, the opening 454 in the cutting blade coincides or aligns with the shelf aperture 475, and the proximal portion 520 of the cord passes through the various components as follows: immediately after exiting the distal end of the housing 100, the cable makes a U-turn and passes through a saddle 480 having a smooth concave lower surface. The cord then passes over a portion of the cutting blade 450 that is distally beyond the opening 454 in the cutting blade, then passes through the opening 454 in the cutting blade and through the aperture 475 in the shelf 470. The cord then passes proximally under the shelf 470 beyond the aperture 475 and continues in a proximal direction through the tool 400. In some preferred embodiments, the saddle 480 and any other features in the tool 400 and fastener 100/200 that contact or potentially contact the cord 500 are rounded to reduce the chance of damaging the cord 500 before it is cut. When the proximal portion of the cord 520 is tightened, the interaction of those components with the proximal portion of the cord 520 will maintain the proximal portion of the cord 520 in a fixed position relative to those components 480, 450, and 470. At this stage of the process, the force of the taut cord 520 holds the fastener 100/200 in place at the distal end of the tool 400 (because the shear pins 310 and 320 have been sheared and are no longer performing this function).

Note that before the cord is gripped by the fastener 100/200 (as described above in connection with fig. 17-18), the proximal portion 520 of the cord passes through the opening 220 of the slide member 200 and over the saddle 408 (as best shown in fig. 8 and 11) through the opening 454 in the cutting blade 450 and through the shelf aperture 475 while the cutting blade remains in its distal position (as best shown in fig. 22). The geometry of the saddle 480 and shelf aperture 475 are configured to suspend the cord 520 over the slit-shaped distal portion 456 of the cutting blade such that the cord 500 does not become lodged against the slit-shaped distal portion 456 of the cutting blade 450 as the cord 500 is passed through the opening 454 in the cutting blade 450 during movement of the tool 400 to its distal-most position (as shown in fig. 8-9) and during retraction of the cord 500 (as shown in fig. 10-11).

Returning to fig. 22, the proximal portion 520 of the cord is then cut by pulling the shaft 460 in a proximal direction, which pulls the cutting blade 450 in a proximal direction. This causes the slit-shaped distal portion 456 of the opening 454 (shown in fig. 23 and 26A) to be pulled in a proximal direction until it reaches the proximal portion of the cord 520. Because the edges of the slit-shaped distal portion 456 are sharpened, further movement of the cutting blade 450 in the proximal direction will cause the slit-shaped distal portion 456 to cut those portions of the cord 520. Continued pulling on the shaft 460 will cause the cutting blade 450 to move further in the proximal direction until it reaches the position shown in fig. 23. The cutting operation will leave two cut ends 526 of the cord. In some preferred embodiments and as best shown in fig. 23, the upper surface of the shelf 470 is aligned with the upper surface of the housing 100 such that the upper surface of the housing 100 extends the sliding platform provided by the shelf 470. In these embodiments, the cutting blade 450 may slide on both a portion of the upper surface of the housing 100 and the shelf 470. Optionally, an alignment feature (e.g., a notch as shown) may be included at the distal end of the shelf 470, and a corresponding alignment feature (e.g., one or more protrusions) may be provided at the proximal end of the housing 100 to improve alignment between the shelf 470 and the housing 100.

Fig. 26A and 26B show upper and lower detailed views of the cutting blade 450, respectively. In the illustrated embodiment, the opening 454 in the cutting blade 450 has: a proximal portion sized wide enough and long enough to allow two segments of the retraction cord 520 to freely slide therethrough; and a slit-shaped distal portion 456 that is sufficiently sharp and narrow to cut the retraction cord 520 when the slit-shaped distal portion 456 encounters the retraction cord 520 and is pulled in a proximal direction against the retraction cord. The slit extends (i.e., is oriented) in a proximal-to-distal direction, and the opening 454 smoothly tapers in a distal direction from the proximal portion toward the slit-shaped distal portion 456. In some embodiments, the body of the cutting blade 450 is made of 304 stainless steel. In alternative embodiments, the body of the cutting blade 450 may be made of any of the materials listed above with respect to the housing 100. In some preferred embodiments, the cutting blade 450 is 7.6mm long (in the proximal-to-distal direction), 1.9mm wide, 0.13mm thick; the proximal portion of the opening 454 in the cutting blade 450 is 1.0mm wide and at least 1.5mm long.

Fig. 27A and 27B show views of a cutting blade 450 at two different points in time during one example of a process for fabricating the cutting blade 450. In this example, a preliminary slit 456p (e.g., having a width of 20-30 μm) is laser cut in the body of the cutting blade 450, as shown in FIG. 27A. Subsequently, the edges of the preliminary slit are swaged towards each other. One way to perform this swaging is to press a tool having two sharpened tips (e.g., made of tool steel) against the surface of the cutting blade 450 in a direction normal to the surface of the cutting blade on either side of the preliminary slit until the edges of the preliminary slit contact each other. When this method is used, the recesses 458 are formed in the surface 452 of the cutting blade 450 and the width of the slits 456 will converge to zero between the recesses 458 as shown in FIG. 27B, thereby forming a V-notch cutting feature with a sharpened cutting edge. As the sharp cutting edge is drawn over the cord 500, it will cut the cord 500. Various alternative methods for forming the slit-shaped distal portion 456 may also be used.

After the cord 500 has been cut (as described above in connection with fig. 23), the tool 400 may be withdrawn in a proximal direction, as shown in fig. 24A and 24B. After the tool 400 is fully withdrawn, all that will remain in the patient is the distal loop portion of the retraction cord 510, the fastener 100/200 (which holds the distal loop portion of the cord 510 securely in a reduced diameter state), and the two truncated ends 526 of the retraction cord, as shown in fig. 25. Note that because the fastener 100/200 holds the distal loop portion of the cord 510 in a reduced diameter state and the cord has been previously secured to the loop, the loop will also be securely held in the reduced diameter state.

Although the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations and changes to the described embodiments are possible without departing from the scope and range of the invention as defined in the appended claims. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.