Heart wall actuation system for the natural heart with shape limiting elements

• US 20040034271A1
• Filed: 08/19/2002
• Published: 02/19/2004
• Est. Priority Date: 08/19/2002
• Status: Active Grant

• Current Assignee: Cardioenergetics, University of Cincinnati
• Original Assignee: Cardioenergetics, University of Cincinnati
• Inventors: Melvin, David B., Melvin, Alan J., Klosterman, Brad A.
• Granted Patent: US 6,988,982 B2
• Time in Patent Office: Days
• US Class Current: 600/16
• CPC Class Codes: A61F 2/2481 Devices outside the heart wall, e.g. bags, strips or bands
• CPC Class Codes: A61M 60/191 mechanically acting upon the outside of the patient's native heart, e.g. compressive structures placed around the heart
• CPC Class Codes: A61M 60/289 Devices for mechanical circulatory actuation assisting the residual heart function by means mechanically acting upon the patient's native heart or blood vessel structure, e.g. direct cardiac compression [DCC] devices
• CPC Class Codes: A61M 60/839 of devices for mechanical circulatory actuation
• CPC Class Codes: A61M 60/861 Connections or anchorings for connecting or anchoring pumps or pumping devices to parts of the patient's body

Abstract

An actuation system for assisting the operation of the natural heart includes an actuator element adapted to be positioned proximate a portion of a heart wall. The actuator element is operable for acting on the heart wall portion to effect a change in the shape of the heart. A shape-limiting element is configured for being positioned proximate a heart wall. The shape-limiting element is operable for flexing to assume a curvature no greater than a predetermined curvature when the heart wall is acted upon and maintaining that predetermined curvature to control the shape of the actuated heart.

Claims

1. An actuation system for assisting the operation of the natural heart, the actuation system comprising:

an actuator element configured for being positioned proximate a portion of a heart wall and operable for acting on the heart wall portion to effect a change in the shape of the heart;

a shape-limiting element configured for being positioned proximate a heart wall, the shape-limiting element operable for flexing to assume a predetermined curvature when the heart wall is acted upon and maintaining that predetermined curvature to control the shape of the heart.

2. The actuation system of claim 1 further comprising a framework for interfacing with a natural heart, the framework including an element configured for being anchored to tissue of the heart and the actuator element adapted to be coupled to the framework.

3. The actuation system of claim 1 wherein shape-limiting element is coupled to the actuator element.

4. The actuation system of claim 2 wherein shape-limiting element is coupled to the actuator element.

5. The actuation system of claim 1 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

at least two adjacent links being shaped to interfere with each other, when the adjacent links are hinged in a direction for a predetermined distance, to limit hinging and to maintain a predetermined curvature of the band.

6. The actuation system of claim 5 wherein the adjacent links include projections extending outwardly from a longitudinal axis of the band, the projections configured for interfering with each other.

7. The actuation system of claim 5 wherein said adjacent links are shaped to interfere with each other when hinged in both one direction and another direction.

8. The actuation system of claim 7 wherein the adjacent links are further configured to maintain one predetermined curvature when hinged in the one direction and to maintain a different predetermined curvature when hinged in the another direction.

9. The actuation system of claim 1 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

a tether spanning between at least two links, the tether having limited extensibility to limit hinging when the links are hinged in a direction for a predetermined distance to thereby maintain a predetermined curvature of the band.

10. The actuation system of claim 1 wherein the shape-limiting element comprises:

an elongated, flexible belt;

a plurality of projections extending outwardly from a longitudinal axis of the belt, the protrusions configured for interfering with each other, when the belt is flexed in a direction for a predetermined distance, to limit flexing and to maintain a predetermined curvature of the belt.

11. The actuation system of claim 1 wherein the shape-limiting element comprises:

an elongated, flexible belt,

a tether fixed to the belt in at least two positions spaced along a longitudinal axis of the belt, the tether having limited extensibility to limit flexing of the belt when the belt is flexed in a direction for a predetermined distance to thereby maintain a predetermined curvature of the belt.

12. The actuation system of claim 1 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

a rigid stop element spanning between at least two links, the stop element configured to engage the links and limit hinging, when the links are hinged in a direction for a predetermined distance, to thereby maintain a predetermined curvature of the band.

13. The actuation system of claim 12 further comprising a rigid stop element spanning the links on opposite sides thereof and limiting hinging in both one direction and another direction.

14. The actuation system of claim 13 wherein the stop elements on the opposite sides of the links are further configured to maintain one predetermined curvature when the links are hinged in the one direction and to maintain a different predetermined curvature when the links are hinged in the another direction.

15. The actuation system of claim 13 wherein the stop elements on the opposite sides are coupled together between the links.

16. The actuation system of claim 15 wherein the stop elements are coupled together to form a generally unitary structure.

17. The actuation system of claim 1 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

a tubular stop element surrounding portions of at least two links and generally coaxial with a longitudinal axis of the band, the stop element configured to engage the links and limit hinging, when the adjacent links are hinged in a direction for a predetermined distance, to thereby maintain a predetermined curvature of the band.

18. The actuation system of claim 1 wherein the shape-limiting element comprises:

a spring structure which is configured to flex;

a sheath interfacing with a portion of the spring structure, the sheath having limited deformability and configured to limit flexing of the spring structure to define said predetermined curvature.

19. The actuation system of claim 18 wherein the sheath encases a portion of the spring structure.

20. The actuation system of claim 18 wherein the spring structure is formed of a shape memory material.

21. A shape-limiting structure for use with a heart wall actuation system having an actuator element to control the shape of an actuated heart, the structure comprising:

a shape-limiting element configured for being positioned proximate a heart wall, the shape-limiting element operable for flexing to assume a predetermined curvature when the heart wall is acted upon for changing its shape, the shape limiting element further configured for maintaining the predetermined curvature to control the shape of the actuated heart.

22. The shape-limiting structure of claim 21 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

at least two adjacent links being shaped to interfere with each other, when the adjacent links are hinged in a direction for a predetermined distance, to limit hinging and to maintain a predetermined curvature of the band.

23. The device of claim 22 wherein the adjacent links include projections extending outwardly from a longitudinal axis of the band, the projections configured for interfering with each other.

24. The device of claim 22 wherein said adjacent links are shaped to interfere with each other when hinged in both one direction and another direction.

25. The shape-limiting structure of claim 21 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

a tether spanning between at least two links, the tether having limited extensibility to limit hinging when the links are hinged in a direction for a predetermined distance to thereby maintain a predetermined curvature of the band.

26. The shape-limiting structure of claim 21 wherein the shape-limiting element comprises:

an elongated, flexible belt;

a plurality of projections extending outwardly from a longitudinal axis of the belt, the projections configured for interfering with each other, when the belt is flexed in a direction for a predetermined distance, to limit flexing and to maintain a predetermined curvature of the belt.

27. The shape-limiting structure of claim 21 wherein the shape-limiting element comprises:

an elongated, flexible belt,

a tether fixed to the belt in at least two positions spaced along a longitudinal axis of the belt, the tether having limited extensibility to limit flexing of the belt when the belt is flexed in a direction for a predetermined distance to thereby maintain a predetermined curvature of the belt.

28. The shape-limiting structure of claim 21 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

a rigid stop element spanning between at least two links, the stop element configured to engage the links and limit hinging when the links are hinged in a direction for a predetermined distance to thereby maintain a predetermined curvature of the band.

29. The shape-limiting structure of claim 28 further comprising a rigid stop element spanning the links on opposite sides thereof and limiting hinging in both one direction and another direction.

30. The shape-limiting structure of claim 29 wherein the stop elements on the opposite sides are coupled together between the links.

31. The shape-limiting structure of claim 30 wherein the stop elements are coupled together to form a generally unitary structure.

32. The shape-limiting structure of claim 21 wherein the shape-limiting element comprises:

a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band;

a tubular stop element surrounding portions of at least two links and generally coaxial with a longitudinal axis of the band, the tubular stop element configured to engage the links and limit hinging when the adjacent links are hinged in a direction for a predetermined distance to thereby maintain a predetermined curvature of the band.

33. A shape-limiting element for use with a heart wall actuation system to control the shape of an actuated heart, the element comprising:

a spring structure which is configured to flex;

a curvature-limiting element interfacing with a portion of the spring structure, the curvature limiting element configured to limit flexing of the spring structure to define a predetermined curvature when the heart wall is acted upon.

34. The shape-limiting element of claim 33 wherein said curvature-limiting element includes a sheath having limited deformability.

35. The shape-limiting element of claim 34 wherein the sheath encases a portion of the spring structure.

36. The shape-limiting element of claim 33 wherein the spring structure is formed of at least one of stainless steel, titanium, and a shape memory material.

37. The shape-limiting element of claim 33 wherein the spring structure includes a plurality of turns, the curvature-limiting element including at least one link configured to couple with turns of the spring structure to limit the separation of the turns when the spring structure is flexed.

38. A method for assisting the operation of the natural heart, the method comprising:

positioning an actuator element proximate to a heart and operating the actuator element to act on a heart wall portion to effect a change in the shape of the heart;

with a shape-limiting element configured for being positioned proximate a heart wall, allowing the shape-limiting element to flex to a predetermined curvature when the heart wall portion is acted upon and maintaining that predetermined curvature to control the shape of the actuated heart.

39. The method of claim 38 further comprising flexing the shape-limiting element with the operation of the actuator element.

40. The method of claim 38 wherein the shape-limiting element comprises a plurality of discrete links positioned to form a band, the links hingedly coupled together to hinge with respect to each other for varying the shape of the band, the method further comprising limiting the hinging of links of the band to maintain a predetermined curvature of the band.

41. The method of claim 40 further comprising limiting the hinging of the links with projections on at least two links wherein the projections interfere with each other when the links are hinged.

42. The method of claim 40 further comprising limiting the hinging of the links with at least one tether spanning between at least two links and having limited extensibility.

43. The method of claim 38 wherein the shape-limiting element comprises an elongated, flexible belt, the method further comprising limiting the flexing of the belt to maintain a predetermined curvature of the belt.

44. The method of claim 43 further comprising limiting the flexing of the belt with a at least one tether fixed to the belt in at least two spaced positions along the belt, the tether having limited extensibility.

45. The method of claim 40 further comprising limiting the hinging of the links with at least one rigid stop element spanning between at least two links, the stop element configured to engage the links and limit hinging.

46. The method of claim 40 further comprising limiting the hinging of the links with at least one tubular stop element surrounding portions of at least two links, the stop element configured to engage the links and limit hinging.

47. The method of claim 38 wherein the shape-limiting element comprises a spring structure which is configured to flex and a sheath interfacing with a portion of the spring structure, the sheath having limited deformability and configured to limit flexing of the spring structure to define said predetermined curvature.

48. The method of claim 38 wherein the shape-limiting element comprises a spring structure including a plurality of turns and at least one link configured to couple with turns of the spring structure to limit the separation of the turns when the spring structure is flexed.