Percutaneous tether locking

1. Apparatus comprising:

a tether-securing device, which comprises a tubular element, which is shaped so as define a lateral wall that entirely surrounds a lumen, wherein the lateral wall is shaped so as to define (a) a one-way locking opening and (b) first and second non-constraining openings at respective different circumferential locations;

at least one tether, which (a) has at least first and second tether end portions, and (b) passes through the lumen, the one-way locking opening, and the first and the second non-constraining openings; and

first and second tissue anchors, connected to the first and the second tether end portions, respectively,

wherein the one-way locking opening is configured to (a) allow sliding of the at least one tether in a first direction through the one-way locking opening, and (b) inhibit sliding of the at least one tether in a second direction opposite the first direction, and

wherein the first and the second non-constraining openings are sized and shaped to allow free sliding therethrough of two longitudinal portions, respectively, of the at least one tether.

2. The apparatus according to claim 1 , wherein the one-way locking opening is shaped as a slit.

3. The apparatus according to claim 1 , wherein the first direction is from inside the tubular element to outside the tubular element.

4. The apparatus according to claim 1 , wherein the one-way locking opening has uneven edges that are jagged or serrated.

5. The apparatus according to claim 1 ,

wherein a single tether of the at least one tether has the first and the second tether end portions,

wherein the single tether comprises at least the following non-overlapping longitudinal portions disposed in sequence along the single tether:

the first tether end portion,

a first portion that passes through the securing-device lumen and the one-way locking opening,

a looped middle portion that extends out of and away from the one-way locking opening, and then loops back to the one-way locking opening,

a second portion that passes through the securing-device lumen and the one-way locking opening, and

the second tether end portion, and

wherein the two longitudinal portions of the at least one tether are two longitudinal portions of the single tether, respectively, and wherein the single tether passes through the first and the second non-constraining openings.

6. The apparatus according to claim 5 , further comprising a fixation tether, which is connected to the looped middle portion of the single tether.

7. The apparatus according to claim 6 , further comprising a venous tissue anchor, which is configured to be implanted in a vein selected from the group of veins consisting of: an inferior vena cava, a superior vena cava, and a coronary sinus, wherein the fixation tether is connected to the venous tissue anchor and the at least one tether.

8. The apparatus according to claim 1 ,

wherein the at least one tether comprises first and second tethers, which (a) have the first and the second tether end portions, respectively, and (b) pass through (i) the lumen and (ii) the one-way locking opening,

wherein the one-way locking opening is configured to (a) allow the sliding of the first and the second tethers in the first direction through the one-way locking opening, and (b) inhibit the sliding of the first and the second tethers in the second direction,

wherein the two longitudinal portions of the at least one tether are a longitudinal portion of the first tether and a longitudinal portion of the second tether, respectively, and

wherein the first and the second tethers pass through the first and the second non-constraining openings, respectively, which are sized and shaped to allow free sliding therethrough of the first and the second tethers, respectively.

9. The apparatus according to claim 1 , further comprising:

a venous tissue anchor, which is configured to be implanted in a vein selected from the group of veins consisting of: an inferior vena cava, a superior vena cava, and a coronary sinus; and

a fixation tether, which is connected to the venous tissue anchor and the at least one tether.

10. The apparatus according to claim 9 , wherein the venous tissue anchor comprises a stent.

11. The apparatus according to claim 1 , wherein the tubular element is cylindrical.

12. Apparatus comprising:

a tether-securing device, which comprises a cylindrical tubular element, which is shaped so as define a lateral wall that entirely surrounds a lumen, wherein the lateral wall is shaped so as to define a one-way locking opening;

at least one tether, which (a) has at least a first tether end portion, and (b) passes through the lumen and the one-way locking opening; and

a first tissue anchor connected to the first tether end portion,

wherein the one-way locking opening is configured to (a) allow sliding of the at least one tether in a first direction through the one-way locking opening, and (b) inhibit sliding of the at least one tether in a second direction opposite the first direction,

wherein the apparatus further comprises a second tissue anchor that comprises a head and a tissue-coupling element, and wherein the tether-securing device is fixed to the head, such that the tether-securing device surrounds at least a portion of the head, and

wherein the lateral wall is shaped so as to define a non-constraining opening, and wherein the at least one tether passes through the non-constraining opening, which is sized and shaped to allow free sliding therethrough of the at least one tether.

13. The apparatus according to claim 12 , wherein the tether-securing device is configured to rotate with respect to the head.

14. The apparatus according to claim 12 , wherein the one-way locking opening is shaped as a slit.

15. The apparatus according to claim 12 , wherein the first direction is from inside the tubular element to outside the tubular element.

16. The apparatus according to claim 12 , wherein the one-way locking opening has uneven edges that are jagged or serrated.

17. A method comprising:

delivering, to a vicinity of an anatomical site of a subject:

(a) a tether-securing device, which includes a tubular element, which is shaped so as define a lateral wall that entirely surrounds a lumen, wherein the lateral wall is shaped so as to define (i) a one-way locking opening and (ii) first and second non-constraining openings at respective different circumferential locations,

(b) at least one tether, which (i) has a first and second tether end portions, and (ii) passes through the lumen, the one-way locking opening, and the first and the second non-constraining openings, wherein the one-way locking opening is configured to (i) allow sliding of the at least one tether in a first direction through the one-way locking opening, and (ii) inhibit sliding of the at least one tether in a second direction opposite the first direction, and wherein the first and the second non-constraining openings are sized and shaped to allow free sliding therethrough of two longitudinal portions, respectively, the at least one tether, and

(c) first and second tissue anchors connected to the first and the second tether end portions, respectively;

implanting the first and the second tissue anchors in tissue of the subject; and

tensioning the at least one tether by sliding the at least one tether in the first direction through the one-way locking opening and the first and the second non-constraining openings.

18. The method according to claim 17 ,

wherein a single tether of the at least one tether has the first and the second tether end portions,

wherein the single tether includes at least the following non-overlapping longitudinal portions disposed in sequence along the single tether:

the first tether end portion,

a first portion that passes through the securing-device lumen and the one-way locking opening,

a looped middle portion that extends out of and away from the one-way locking opening, and then loops back to the one-way locking opening,

a second portion that passes through the securing-device lumen and the one-way locking opening, and

the second tether end portion,

wherein the two longitudinal portions of the at least one tether are two longitudinal portions of the single tether, respectively, and wherein the single tether passes through the first and the second non-constraining openings, and

wherein tensioning the at least one tether comprises proximally sliding the first and the second portions of the single tether through the one-way locking opening in the first direction by pulling, in the first direction, on the looped middle portion.

19. The method according to claim 18 , further comprising connecting a fixation tether to the looped middle portion of the single tether.

20. The method according to claim 19 , further comprising implanting a venous tissue anchor, which is connected to the fixation tether, in a vein selected from the group of veins consisting of: an inferior vena cava, a superior vena cava, and a coronary sinus.

21. The method according to claim 17 ,

wherein the at least one tether includes first and second tethers, which (a) have the first and the second tether end portions, respectively, and (b) pass through (i) the lumen and (ii) the one-way locking opening,

wherein the one-way locking opening is configured to (a) allow the sliding of the first and the second tethers in the first direction through the one-way locking opening, and (b) inhibit the sliding of the first and the second tethers in the second direction,

wherein the two longitudinal portions of the at least one tether are a longitudinal portion of the first tether and a longitudinal portion of the second tether, respectively, and wherein the first and the second tethers pass through the first and the second non-constraining openings, respectively, which are sized and shaped to allow free sliding therethrough of the first and the second tethers, respectively, and

wherein tensioning the at least one tether comprises tensioning the first and the second tethers by sliding the first and the second tethers (a) in the first direction through the one-way locking opening and (b) through the first and the second non-constraining openings, respectively.

22. The method according to claim 17 , wherein the one-way locking opening is shaped as a slit.

23. The method according to claim 17 , wherein the first direction is from inside the tubular element to outside the tubular element.

24. The method according to claim 17 , wherein the one-way locking opening has uneven edges that are jagged or serrated.

25. The method according to claim 17 , further comprising:

implanting a venous tissue anchor in a vein selected from the group of veins consisting of: an inferior vena cava, a superior vena cava, and a coronary sinus; and

connecting, to the at least one tether, a fixation tether which is connected to the venous tissue anchor.

26. The method according to claim 17 , wherein the tubular element is cylindrical.

27. A method comprising:

delivering, to a vicinity of an anatomical site of a subject:

(a) a tether-securing device, which includes a cylindrical tubular element, which is shaped so as define a lateral wall that entirely surrounds a lumen, wherein the lateral wall is shaped so as to define a one-way locking opening,

(b) at least one tether, which (i) has at least a first tether end portion, and (ii) passes through the lumen and the one-way locking opening, wherein the one-way locking opening is configured to (i) allow sliding of the at least one tether in a first direction through the one-way locking opening, and (ii) inhibit sliding of the at least one tether in a second direction opposite the first direction, and

(c) a first tissue anchor connected to the first tether end portion;

implanting the first tissue anchor in tissue of the subject; and

delivering a second tissue anchor that includes a head and a tissue-coupling element, and wherein the tether-securing device is fixed to the head, such that the tether-securing device surrounds at least a portion of the head,

wherein the lateral wall is shaped so as to define a non-constraining opening, which is sized and shaped to allow free sliding therethrough of the at least one tether,

tensioning the at least one tether by sliding the at least one tether (a) in the first direction through the one-way locking opening and (b) through the non-constraining opening.

28. The method according to claim 27 , wherein the tether-securing device is configured to rotate with respect to the head.

29. The method according to claim 27 , wherein the one-way locking opening is shaped as a slit.

30. The method according to claim 27 , wherein the first direction is from inside the tubular element to outside the tubular element.

31. The method according to claim 27 , wherein the one-way locking opening has uneven edges that are jagged or serrated.