Hybrid expandable device

Abstract

The present technology relates to the treatment of heart valves. Many embodiments of the present technology include an anchoring member configured to be positioned at an implant site proximate to a valve annulus of a native valve. The anchoring member can include an expandable structure having a first portion and a second portion. The first portion is configured to self-expand into attachment with tissue at or near the valve annulus to secure the anchoring member at the implant site when the first portion is positioned at the implant site at body temperature and released from a constrained delivery state. The second portion remains in a low-profile state at or near body temperature and is configured to expand into attachment with tissue at or near the valve annulus when heated to a second temperature that is higher than the first temperature and body temperature.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 862,433, filed June 17, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This technology relates to artificial heart valve devices. In particular, several embodiments relate to artificial valves and devices for percutaneous repair and / or replacement of heart valves, as well as related systems and methods of use. Background Technology

[0004] Transcatheter aortic valve replacement (“TAVR”) is a relatively new, less invasive treatment for severe symptomatic aortic stenosis. TAVR involves delivering an artificial heart valve through a catheter to the annulus of an autologous valve, thus avoiding open cardiac surgery and its associated risks. The artificial heart valve expands from its low-profile state (for catheter delivery) to its expanded state at the annulus of the autologous valve; this expansion typically occurs via self-expansion of the artificial valve structure or balloon dilation.

[0005] For patients ineligible for surgery, TAVR is recommended as an alternative to conventional surgical aortic valve replacement. In these ineligible patients, studies have shown that TAVR significantly reduces all-cause mortality, repeat hospitalizations, and cardiac symptoms compared to standard therapies, including balloon valvuloplasty. For patients at high surgical risk, survival after TAVR is comparable to that of surgical replacement, but perioperative risks differ. For example, recent studies have shown that treatment using self-expanding transcatheter valves is associated with a greater risk of postoperative left bundle branch block (“LBBB”) and more frequent need for a new permanent pacemaker compared to balloon-expandable valves. However, treatment using self-expanding valves is associated with better valvular hemodynamics and a lower mean gradient. Therefore, there is a need for improved transcatheter valve replacement and / or repair devices and delivery systems. Summary of the Invention

[0006] This technology relates to artificial heart valve devices. In particular, several embodiments relate to artificial valves and devices for percutaneous repair and / or replacement of heart valves, as well as related systems and methods of use. For example, references are made to various aspects described below. Figure 1-1 1. To illustrate the technical subject matter. For convenience, various examples of different aspects of the technical subject matter are described as numbered clauses (1, 2, 3, etc.). These are provided as examples and do not limit the technical subject matter.

[0007] 1. An anchoring member configured to be positioned at a treatment site near the valve annulus of an autologous valve in a human patient, the anchoring member comprising:

[0008] An expandable structure comprising a first portion and a second portion, each having a low-profile state and an expanded state, wherein, when the expandable structure is positioned at a treatment site and released from a catheter at a first temperature not exceeding approximately 40°C:

[0009] The first part expands towards its expanded state and extends to attach to the tissue at or near the valve annulus to fix the anchoring member at the treatment site, and

[0010] The second part remains in its low profile state.

[0011] The second part of the expandable structure is configured to expand and attach to tissue at or near the valve annulus when heated to a second temperature higher than the first temperature.

[0012] 2. The anchoring member as described in Clause 1, wherein the second portion is formed of a shape memory alloy (“SMA”) having an austenite finishing temperature A that is (a) greater than or equal to a second temperature and (a) greater than body temperature. f .

[0013] 3. An anchoring member as described in Clause 1 or Clause 2, wherein the first temperature is about 36°C to about 40°C.

[0014] 4. An anchoring member as described in Clause 1 or Clause 2, wherein the first temperature is about 36°C to about 39°C.

[0015] 5. An anchoring member as described in Clause 1 or Clause 2, wherein the first temperature is about 36°C to about 38°C.

[0016] 6. An anchoring member as described in any of Clauses 2 to 5, wherein the second temperature is not lower than 37°C.

[0017] 7. An anchoring member as described in any of Clauses 2 to 5, wherein the second temperature is not lower than 38°C.

[0018] 8. An anchoring member as described in any of Clauses 2 to 5, wherein the second temperature is not lower than 39°C.

[0019] 9. An anchoring member as described in any of Clauses 2 to 5, wherein the second temperature is not lower than 40°C.

[0020] 10. An anchoring member as described in any of Clauses 2 to 5, wherein the second temperature is about 37°C to about 40°C.

[0021] 11. An anchoring member as described in any of Clauses 2 to 5, wherein the second temperature is about 38°C to about 40°C.

[0022] 12. An anchoring member as described in any of Clauses 2 to 5, wherein the second temperature is about 39°C to about 40°C.

[0023] 13. An anchoring member as described in any of the preceding clauses, wherein the second part is made of martensite at temperature M. f Greater than or equal to the first temperature and the austenite completion temperature A f SMA formation at a temperature less than or equal to the second temperature.

[0024] 14. An anchoring member as described in any of the preceding clauses, wherein the second part is formed by the martensitic initiation temperature M. s Greater than or equal to the first temperature and the austenite completion temperature A f SMA formation at a temperature less than or equal to the second temperature.

[0025] 15. An anchoring member as described in any of the preceding clauses, wherein the second portion is formed of an SMA having the following characteristics:

[0026] Martensite completion temperature M f Greater than or equal to the first temperature

[0027] Martensite initiation temperature M s Greater than or equal to the first temperature, and

[0028] Austenite completion temperature A f Less than or equal to the second temperature.

[0029] 16. An anchoring member as described in any of Clauses 1 to 14, wherein the second part is formed of an SMA having the following characteristics:

[0030] Martensite completion temperature M f Less than the first temperature,

[0031] Martensite initiation temperature M s Greater than or equal to the first temperature, and

[0032] Austenite completion temperature A f Less than or equal to the second temperature.

[0033] 17. An anchoring member as described in any of the preceding clauses, wherein the second part has an austenitic finish temperature A of less than 37°C. f .

[0034] 18. An anchoring member as described in any of the preceding clauses, wherein the expandable structure is configured such that: when implanted at the annulus of the autologous flap, the second portion is upstream of the first portion.

[0035] 19. An anchoring member as described in any of the preceding clauses, wherein the expandable structure is configured such that, when implanted at or near the annulus of an autologous aortic valve, (a) at least a portion of the first portion is located within the aorta, and (b) at least a portion of the second portion is located within the left ventricle.

[0036] 20. An anchoring member as described in any of the preceding clauses, wherein the expandable structure is configured such that when implanted at or near the annulus of an autologous aortic valve, no portion of the first part is pressed outward against the left ventricle.

[0037] 21. An anchoring member as described in any of the preceding clauses, wherein the expandable structure is configured such that when implanted at or near the annulus of the patient's aortic valve, no portion of the first part is distal to the annulus.

[0038] 22. An anchoring member as described in any of the preceding clauses, wherein when the expandable structure is implanted at or near the annulus of the autologous aortic valve such that both the first part and the second part expand and come into contact with adjacent tissue, the force by which the first part presses against the adjacent tissue outward is greater than the force by which the second part presses against the adjacent tissue outward.

[0039] 23. An anchoring member as described in any of the preceding clauses, wherein the autologous valve is an aortic valve.

[0040] 24. An anchoring member as described in any of the preceding clauses, wherein the self-lobe is the mitral valve.

[0041] 25. An anchoring member as described in any of the preceding clauses, wherein the second part is thermally expandable.

[0042] 26. An anchoring member as described in any of the preceding clauses, wherein the second portion does not self-expand when at or below the second temperature.

[0043] 27. An anchoring member as described in any of the preceding clauses, wherein the second part is an SMA.

[0044] 28. An anchoring member as described in any of the preceding clauses, wherein the second part is Nitinol.

[0045] 29. An anchoring member as described in any of the preceding clauses, wherein each of the first and second parts comprises an SMA.

[0046] 30. An anchoring member as described in any of the preceding clauses, wherein the first portion comprises a first SMA and the second portion comprises a second SMA different from the first SMA.

[0047] 31. An anchoring member as described in any of the preceding clauses, wherein the first portion comprises a first SMA containing a first metal and a second metal, and the second portion comprises a second SMA containing a first metal and a second metal, wherein the ratio of the first metal to the second metal in the first SMA is different from the ratio of the first metal to the second metal in the second SMA.

[0048] 32. An anchoring member as described in any of the preceding clauses, wherein the expandable structure is formed by a plurality of interconnected struts.

[0049] 33. An anchoring member as described in any of the preceding clauses, wherein, at least when the anchoring member is in an unrestrained expanded state, the angle between adjacent struts in the first part is smaller than the angle between adjacent struts in the second part.

[0050] 34. An anchoring member as described in any of the preceding clauses, wherein the strut constituting the second part has a substantially square cross-section.

[0051] 35. An anchoring member as described in any of the preceding clauses, wherein the ratio of the thickness to the width of the strut constituting the second part is approximately 1.

[0052] 36. An anchoring member as described in any of the preceding clauses, wherein the strut constituting the first part has a different cross-sectional shape than the strut constituting the second part.

[0053] 37. An anchoring member as described in any of the preceding clauses, wherein, when in an expanded state, the second portion is more rigid than the first portion.

[0054] 38. An anchoring member as described in any of the preceding clauses, wherein the first portion is configured to apply a continuous elastic force to adjacent tissue when the device is implanted.

[0055] 39. An expandable device configured to be positioned at an implantation site near the annulus of an autologous flap, the expandable device comprising:

[0056] Anchoring member, the anchoring member comprising:

[0057] An expandable structure including the first and second parts.

[0058] When the first portion is positioned at the implantation site at a first temperature and released from a constrained delivery state, the first portion is configured to self-expand to attach to tissue at or near the valve annulus to secure the anchoring member at the implantation site.

[0059] The second portion remains in a low-profile state at the first temperature and is configured to expand and attach to tissue at or near the valve annulus when heated to a second temperature above the first temperature to secure the anchoring component at the implantation site; and

[0060] An artificial valve configured to be supported by an anchoring member, installed within an anchoring member, or connected to an anchoring member.

[0061] 40. An expandable device as described in any of the preceding clauses, wherein the anchoring member includes any of the devices described in clauses 1 to 38.

[0062] 41. A system for treating an autologous heart valve in a human patient, the system comprising:

[0063] jacket;

[0064] An anchoring member configured to be delivered via a sheath to a treatment site adjacent to the valve annulus of the autologous valve, the anchoring member comprising:

[0065] An expandable structure including the first and second parts.

[0066] When the first portion is positioned at the treatment site at a first temperature and released from a constrained delivery state, the first portion is configured to self-expand to attach to tissue at or near the valve annulus to secure the anchoring member at the treatment site.

[0067] The second part remains in a low profile state at the first temperature and is configured to expand to attach to the tissue at or near the valve annulus when heated to a second temperature higher than the first temperature.

[0068] An artificial valve, configured to be supported by an anchoring member, installed within an anchoring member, or connected to an anchoring member;

[0069] An elongated member having a proximal end portion and a distal end portion, the proximal end portion being configured to be positioned in an external location during implantation of an expandable structure, and the distal end portion being configured to be delivered to the treatment site via a sheath; and

[0070] A heating element carried by the distal end portion of an elongated member, wherein the heating element is configured to cause the second portion to be heated to a second temperature.

[0071] 42. The system as described in any of the preceding clauses, wherein the heating element is a plurality of openings in the distal end portion of the elongated member, and wherein the system further includes a fluid source coupled to the proximal end portion of the elongated member and configured to deliver heated fluid through an interior cavity extending through the elongated member and through the plurality of openings to a fluid source near the second portion.

[0072] 43. The system as described in any of the preceding clauses, wherein the heating element is a balloon carried by the distal end portion of the elongated member, and wherein the system further includes a fluid source coupled to the proximal end portion of the elongated member and configured to deliver heated fluid through an interior cavity extending through the elongated member to the balloon.

[0073] 44. The system as described in any of the preceding clauses, wherein the heating element is an expandable basket carried by the distal end portion of an elongated member, and wherein the system further includes a power source connected to the elongated member, and wherein at least a portion of the elongated member is conductive, such that when the power source is activated, the elongated member transfers energy to the basket, thereby heating and expanding the basket.

[0074] 45. A system as described in any of the preceding clauses, wherein the heating element is an electrode in direct contact with the second portion, and wherein an electric current is applied to the elongated member to allow the current to pass through the second portion, thereby heating the second portion and causing it to expand.

[0075] 46. ​​The system as described in any of the preceding clauses, wherein the anchoring member is any of the anchoring members described in clauses 1 to 38.

[0076] 47. A method for treating an autologous heart valve in a human patient, the method comprising:

[0077] The anchoring member is delivered to the autologous flap region. The anchoring member includes an expandable structure formed by a plurality of struts, wherein the expandable structure includes a self-expandable first part and a thermally expandable second part.

[0078] The first portion is released from the delivery sheath, thereby allowing the first portion to self-expand and attach to the tissue at the autologous flap region; and

[0079] The second part is heated to a temperature above 37°C to transform it from a low-profile delivery state to an expanded state in which the second part contacts the tissue in the autologous flap region.

[0080] 48. The method as described in any of the preceding clauses, wherein releasing the first portion includes releasing the first portion such that the first portion self-expands to attach to tissue downstream of the valve annulus.

[0081] 49. The method as described in any of the preceding clauses, wherein the valve is an aortic valve, and the method further comprises positioning at least a portion of the first portion in contact with the aortic wall and positioning at least a portion of the second portion in contact with the left ventricular wall.

[0082] 50. The method described in any of the preceding clauses, wherein the heart valve is the aortic valve.

[0083] 51. The method described in any of the preceding clauses, wherein the heart valve is the mitral valve.

[0084] 52. The method described in any of the preceding clauses, wherein the release of the first part takes place before the heating of the second part.

[0085] 53. The method described in any of the preceding clauses, wherein the release of the first part occurs at least partially while the second part is being heated.

[0086] 54. The method described in any of the preceding clauses, wherein the release of the first part is carried out after the heating of the second part.

[0087] 55. The method as described in any of the preceding clauses, wherein heating the second portion includes infusing heated fluid into the distal portion while positioned at the annulus of the autologous valve.

[0088] 56. The method as described in any of the preceding clauses, wherein heating the second portion includes positioning the balloon at least partially within the cavity of the second portion and inflating the balloon with heated fluid.

[0089] 57. The method as described in any of the preceding clauses, wherein heating the second portion includes positioning the expandable member at least partially within the cavity of the second portion and heating the expandable member.

[0090] 58. The method as described in any of the preceding clauses, wherein heating the second part comprises delivering an electric current through the second part.

[0091] 59. The method described in any of the preceding clauses, wherein the second portion does not self-expand when at or below the first temperature.

[0092] 60. The method described in any of the preceding clauses, wherein the second part is SMA.

[0093] 61. The method described in any of the preceding clauses, wherein the second part is Nitinol.

[0094] 62. The method described in any of the foregoing clauses, wherein each of the first and second parts includes SMA.

[0095] 63. The method described in any of the preceding clauses, wherein the first part includes a first SMA and the second part includes a second SMA different from the first SMA.

[0096] 64. The method as described in any of the preceding clauses, wherein the first part comprises a first SMA containing a first metal and a second metal, and the second part comprises a second SMA containing a first metal and a second metal, wherein the ratio of the first metal to the second metal in the first SMA is different from the ratio of the first metal to the second metal in the second SMA. Attached Figure Description

[0097] Many aspects of this disclosure can be better understood with reference to the following figures. The components in the figures are not necessarily drawn to scale. Rather, the focus is on clearly illustrating the principles of this disclosure.

[0098] Figure 1 An expandable device of this technology is shown implanted at an autologous aortic valve.

[0099] Figure 2A These are hysteresis curves illustrating the performance of shape memory alloys with different characteristic temperatures at 37°C.

[0100] Figure 2B and 2C This is a hysteresis curve illustrating the performance of the expandable device of this technology at a certain temperature.

[0101] Figures 3A-3C A method for implanting the expandable device of this technology using a retrograde approach is described.

[0102] Figure 4A-7C Various devices, systems, and methods according to the present technology for delivering thermal energy to an expandable device located at the annulus of an autologous valve are described.

[0103] Figure 8 and 9 The strut angles of a conventional self-expanding device and a balloon-expandable stent are shown respectively.

[0104] Figure 10A and 10B These are the cross-sections of the struts of a typical self-expanding device and a balloon-expandable device, respectively.

[0105] Figure 11 is a table showing conventional self-expanding devices and balloon-expandable devices. Specific Implementation

[0106] The following reference Figure 1-11. Specific details describing several embodiments of the present technology. Although many embodiments are described below with respect to devices, systems, and methods for percutaneous replacement of autologous aortic valves, other applications and other embodiments besides those described herein are also within the scope of the present technology, such as devices, systems, and methods for percutaneous replacement of autologous mitral valves. Furthermore, several other embodiments of the present technology may have different constructions, components, or procedures than those described herein. Therefore, those skilled in the art will accordingly understand that the present technology may have other embodiments with additional elements, or the present technology may have embodiments without the following references. Figure 1-1 Other embodiments of some of the features shown and described in Figure 1.

[0107] Regarding the terms “distal” and “proximal” in this specification, unless otherwise stated, these terms may refer to the relative position of the parts of the prosthetic valve device and / or associated delivery device with respect to the operator and / or the location within the vascular system or the heart. For example, when referring to delivery catheters suitable for delivering and positioning the various prosthetic valve devices described herein, “proximal” may refer to a location closer to the operator of the device or to the incision in the vascular system, and “distal” may refer to a location further from the operator of the device or further away from the incision along the vascular system (e.g., the tip of the catheter).

[0108] As previously mentioned, traditional TAVR devices are typically either self-expanding or balloon-expandable, each with its own unique advantages and disadvantages. For example, self-expandable structures do not require a balloon or other components to facilitate expansion, thus allowing delivery within (a) a smaller catheter compared to balloon-expandable structures, and (b) without obstructing blood flow at the treatment site during the procedure. Procedures using balloon-expandable structures require a temporary reduction in the patient's cardiac output during balloon expansion. This reduction is typically achieved through rapid ventricular pacing (“RVP”), and some evidence suggests that patients undergoing RVP during TAVR procedures may have higher in-hospital and long-term mortality rates compared to those undergoing TAVR without RVP. However, self-expandable structures also carry certain risks. For example, recent studies have shown that treatment with self-expandable valve structures is associated with a higher risk of postoperative left bundle branch block (“LBBB”) and a more frequent need for a new permanent pacemaker (compared to balloon-expandable valves). It is believed that the increased incidence of LBBB is at least in part caused by the constant elastic force exerted by a self-expanding stent on a portion of the left ventricular wall corresponding to the left bundle branch (“LBB”) of the heart’s electrical conduction system. Sustained outward pressure on the LBB blocks electrical signals from the LBB to other parts of the heart (leading to LBBB), thus disrupting the heart’s normal contraction pattern and necessitating the implantation of a permanent pacemaker.

[0109] To address these challenges, the expandable device of this technology includes an expandable hybrid stent structure that leverages the multiphase properties of shape memory alloys (such as nitinol) to impart the clinical benefits of both self-expanding and balloon-expandable structures, while reducing or eliminating the associated disadvantages. For example, Figure 1 An expandable device 100 (or "device 100") of this technology, implanted in the autologous aortic valve region of the heart, is depicted. Figure 1 As shown, the device 100 may include an anchoring member 110 and an artificial valve 120 (not visible), which is coupled to, installed within, or otherwise carried by the anchoring member 110. In some embodiments, the device 100 includes only the anchoring member 110 and does not include the artificial valve 120. The anchoring member 110 may be in a low-profile delivery configuration (not shown) and a deployment configuration (not shown). Figure 1 Movement between ) In the delivery configuration, the expandable device 100 has a low profile suitable for delivery through a small-diameter guiding catheter configured to be positioned in the heart via transseptal, retrograde, or transapical means.

[0110] like Figure 1 As shown, the anchoring member 110 may include a support-like structure formed by a plurality of interconnected struts 116 (only one is labeled for illustration purposes) surrounding a central lumen. The anchoring member 110 may have a first end portion 110a, a second end portion 110b, and a length extending along the longitudinal axis of the anchoring member 110 between the first end portion and the second end portion. The anchoring member 110 is configured to be deployed at the annulus of an autologous valve (such as the annulus of an aortic valve or the annulus of a mitral valve) such that the second end portion 110b is positioned upstream or distal to the first end portion 110a.

[0111] The anchoring member 110 may include a self-expanding first portion 112 and a thermally expandable (or balloon-expandable) second portion 114. When implanted at the autologous valve region of the aortic valve, the anchoring member 110 is configured to be positioned such that the self-expanding first portion 112 is downstream of the thermally expandable second portion 114. Thus, the self-expanding first portion 112 can be positioned to attach to the inner surface of the aortic wall, valve annulus tissue, and / or the leaflet of the autologous valve. Preferably, the self-expanding portion 112 does not press outward against any portion of the left ventricular wall or other tissue that coincides with the location of the heart's LBB or other conduction units. The thermally expandable second portion 114 of the anchoring member 110 can be positioned to attach to the aortic wall, the autologous valve leaflet, valve annulus tissue, and / or the left ventricular wall. In some embodiments, the entire thermally expandable portion 114 is located upstream of the valve annulus and within the left ventricle. As discussed elsewhere in this article, the thermally expandable portion 114 does not exert continuous outward forces on the left ventricular wall, thereby eliminating or reducing the disruption of the cardiac electrical conduction system (compared to similarly positioned self-expanding structures).

[0112] In several aspects of this technology, all or part of the self-expanding portion 112 and all or part of the thermally expandable portion 114 of the anchoring member 110 may be formed of a shape memory alloy (“SMA”). SMA is a unique class of metallic alloys that, when heated above a certain temperature, can recover its “memory” shape. SMA has two stable phases: (a) austenitic or high-temperature phase, in which SMA is more rigid and hyperelastic; and (b) martensitic or low-temperature phase, in which SMA is easily deformable. SMA has four characteristic temperatures: (a) the martensitic initiation temperature (M… s (a) the temperature at which the material undergoing cooling begins to transform from austenite to martensite; (b) the martensite completion temperature (M f (c) Austenite initiation temperature (A) s At this temperature, the heated SMA begins its reverse transformation (austenite to martensite); and (d) the austenite completion temperature (A f At this temperature, the reverse phase transformation is completed, and SMA is in the austenitic phase.

[0113] Figure 2A These are hysteresis curves illustrating the performance of SMAs with different characteristic temperatures at approximately 37°C (e.g., the average body temperature of human patients). It should be understood that the following discussion also applies to other reference temperatures besides approximately 37°C, depending on the SMA. Figure 2A The first scenario describes M f SMA above approximately 37°C. In this case, A fThe complete expansion of the SMA occurs at higher temperatures (relative to cases 2-4); however, when the SMA is cooled to 37°C, it will completely transform into martensite. The second case describes the M... s Greater than 37℃ and M f SMA below 37°C. In this case, A f A is lower than that in the first case. f Therefore, complete expansion occurs at a lower temperature than in the first case. When cooled to 37°C, the SMA will be in a mixed martensite / austenite phase. The third case depicts A... s Greater than 37℃ and M s SMA below 37°C. Here, A f Lower than A in the first and second scenarios f Therefore, complete expansion occurs at a lower temperature than in the first and second cases. When the SMA in the third case is cooled to 37°C, the SMA will still be fully austenitic. The fourth case describes A... f Greater than 37℃ and A s The SMA is below 37°C. Therefore, the full expansion of the SMA occurs at a temperature very close to (but still above) 37°C, and the SMA will remain in its fully expanded austenitic phase at 37°C.

[0114] In some embodiments, all or a portion of the self-expanding portion 112 of the anchoring member 110 may be formed of SMA or other materials configured to self-expand to a predetermined expansion shape at temperatures below 36°C. For example, the self-expanding portion 112 may have an austenite finishing temperature A of less than 36°C. f The self-expanding portion 112 is typically slightly larger in size, so that during implantation, the self-expanding portion 112 applies a continuous elastic force to adjacent tissues to secure the expandable device 100 at the treatment site.

[0115] According to several embodiments of the present technology, all or a portion of the thermally expandable portion 114 may be at least partially made of materials conforming to… Figure 2A The standard SMA formed according to the first or second scenario described herein. Such SMAs include, for example, Nitinol. It should be understood that other SMAs conforming to the standards detailed herein may be used with any option of the thermally expandable portion 114, expandable device, and / or anchoring member of this technology.

[0116] like Figure 2B As depicted, in some embodiments, all or a portion of the thermally expandable portion 114 may have an M greater than or equal to a first temperature. f and A less than or equal to the second temperature fThe second temperature is higher than the first temperature. For example, the second temperature can be higher than body temperature. Unless otherwise expressly stated, "body temperature" as used herein means a temperature of about 36°C to about 40°C, about 36°C to about 39°C, or about 36°C to about 38°C, or not exceeding 40°C. A of the thermally expandable portion 114 f And / or the second temperature may be 37°C or higher, 38°C or higher, 39°C or higher, 40°C or higher, from about 37°C to about 40°C, from about 38°C to about 40°C, or from about 39°C to about 40°C.

[0117] Thus, when the thermally expandable portion 114 is positioned within the delivery sheath and / or body at or below the first temperature, it is in a low-profile martensitic state. Therefore, during delivery through the delivery sheath, the thermally expandable portion 114 exerts little or no outward force on the inner wall of the delivery sheath, thereby improving ease of delivery through the sheath (relative to a self-expanding structure). When the thermally expandable portion 114 is released from the delivery sheath and heated to a second temperature or above, it fully expands to its "memory" or more rigid austenitic state. When the thermally expandable portion 114 subsequently cools from the second temperature / austenitic state to a temperature equal to or below the first temperature, it transforms to its more ductile fully martensitic state. In this fully martensitic state, the thermally expandable portion 114 remains in contact with adjacent tissue at the treatment site. However, unlike typical self-expanding structures, the thermally expandable portion 114 does not exert constant outward pressure on adjacent tissues, thus reducing or eliminating the possibility of LBBB development compared to conventional self-expanding scaffolds with similar positioning.

[0118] like Figure 2C As depicted, in some embodiments, all or a portion of the thermally expandable portion 114 may have an M temperature lower than the first temperature. f M greater than or equal to the first temperature s and A less than or equal to the second temperature fThe second temperature is higher than the first temperature. Thus, when the thermally expandable portion 114 is positioned within the delivery sheath and / or body at or below the first temperature, the thermally expandable portion 114 is in a fully martensitic state. Therefore, during delivery through the delivery sheath, the thermally expandable portion 114 exerts little or no outward force on the inner wall of the delivery sheath, thereby improving the ease of delivery through the sheath (compared to a self-expanding structure). When the thermally expandable portion 114 is heated to or above the second temperature, it fully expands to its "memory" or more rigid austenitic state. When the thermally expandable portion 114 is subsequently cooled from the second temperature / austenitic state to a temperature equal to or below the first temperature, it transforms to its more ductile partially martensitic state. In this partially martensitic state, the thermally expandable portion 114 maintains contact with adjacent tissue at the treatment site, but unlike a typical self-expanding structure, the thermally expandable portion 114 exerts only slight pressure on the adjacent tissue. In cases where a stiffer / more rigid implant is required, this embodiment may be superior to the one described above. Figure 2B Detailed examples of fully martensitic structures.

[0119] In any of the embodiments described herein, the first temperature may be close to the upper limit of human body temperature, such as 40°C, and the second temperature may be greater than 40°C. In some embodiments, the first temperature is about 36°C to about 40°C, about 36°C to about 39°C, or about 36°C to about 38°C, and the second temperature is not lower than 37°C, not lower than 38°C, not lower than 39°C, or not lower than 40°C, about 37°C to about 40°C, about 38°C to about 40°C, or about 39°C to about 40°C.

[0120] The self-expanding portion 112 and the heat-expandable portion 114 may constitute the entire anchoring member 110 or only a part of the anchoring member 110. In some embodiments, the self-expanding portion 112 and the heat-expandable portion 114 abut against each other along the length of the anchoring member 110, while in other embodiments, the self-expanding portion 112 and the heat-expandable portion 114 are spaced apart along the length of the anchoring member 110, or are mechanically connected to each other at a joint. The self-expanding portion 112 and the heat-expandable portion 114 may have the same or different lengths, and / or may extend around all or part of the outer periphery of the anchoring member 110. All or part of the self-expanding portion 112 may be radially aligned or overlap with all or part of the heat-expandable portion 114.

[0121] All or part of the self-expanding portion 112 may be formed of a first alloy, and all or part of the thermally expandable portion 114 may be formed of a second alloy different from the first alloy. The first alloy may be an SMA (Super-Aluminum Metallic Acid). In some embodiments, the first alloy is not an SMA. In some embodiments, both the first alloy and the second alloy are SMAs. In such embodiments, each of the first alloy and the second alloy may consist of a mixture of metals of the same type but in different proportions, such that the first alloy and the second alloy have different transformation temperatures. For example, in some embodiments, the first alloy and the second alloy may include nitinol, but the ratio of nickel to titanium in the first alloy may be different from the ratio of nickel to titanium in the second alloy. In some embodiments, both the first alloy and the second alloy are SMAs, but have at least one different metal. In some embodiments, both the first alloy and the second alloy are SMAs, but do not have any common metal.

[0122] In embodiments where two separate and distinct stents (e.g., one stent for the thermally expandable portion 114 and one stent for the self-expanding portion 112) are joined to form expandable devices and / or anchoring members with different transition temperatures, various methods can be used to join the two stents to ensure structural integrity while still minimizing the total compression diameter. For example, the stents can be joined using rivets, sutures, or other connectors. Preferably, these connections can be made proximal to the valve to avoid any increase in the total diameter of the stent valve during delivery. The separate stents can be positioned end-to-end such that their adjacent ends abut and contact each other but do not overlap axially. In some embodiments, the separate stents can overlap each other along a portion of their length. In some embodiments, the adjacent ends of the separate stents can be spaced apart along the length of the stent. In those embodiments, connecting elements and / or additional structural components can span the distance between the two stents.

[0123] In some embodiments, the thermally expandable portion 114 and the self-expanding portion 112 may be manufactured from a single piece of SMA to form a monolithic structure. In such embodiments, the thermally expandable portion 114 and the self-expanding portion 112 are integrally formed with each other. The transition temperatures of the two portions can be differentiated through careful heat treatment, with one portion remaining cooler while the other is annealed for an additional period. Achieving this may include securing the support with a heat sink or cooling element to keep one portion cool while the other is heated. Precise securing makes the transition from one support portion to another more specific.

[0124] Any anchoring member and / or expandable device (or part thereof) disclosed herein may be formed from laser-cut tubes, braids formed from multiple filaments, woven fabrics, and other suitable mesh structures. The term "support" as used herein refers to any of the aforementioned mesh structures.

[0125] In some embodiments, the expandable device and / or anchoring member may include more than two separate structures (e.g., three supports, four supports, etc.).

[0126] Figures 3A-3C The method of implanting the expandable device 100 using a retrograde approach is described. It should be understood that the expandable device 100 of this technology can be delivered to the autologous valve region using other methods, such as antegrade, transseptal, or transapical approaches. Figures 3A-3C As shown, the expandable device 100 can be delivered intravascularly to a desired location in the heart, such as an intracardiac location near the aortic valve, while simultaneously being in a delivery (e.g., collapsed) configuration within the delivery catheter or sheath 230. The device 100 can advance to a location where the thermally expandable portion 114 is located in or upstream of the autologous valve annulus, such as... Figure 3A As shown. Then, the sheath 230 can be withdrawn proximally beyond the thermally expandable portion 114 and the self-expanding portion 112, thereby releasing the self-expanding portion 112, allowing it to self-expand to attach to tissue at or downstream of the autologous valve annulus, such as... Figure 3B and 3C As shown. Figure 3C As depicted, a fluid 234 having a second temperature higher than the first temperature can be infused at or upstream of the thermally expandable portion 114 via an elongated shaft 232 extending through the lumen of the thermally expandable portion 114. Upon reaching the second temperature, the thermally expandable portion 114 expands into its austenitic shape to which it attaches to adjacent tissue. Compared to balloon-expandable devices, the expandable device 100 of this technology expands without the use of a balloon, thus avoiding the challenges associated with aortic obstruction during deployment. However, if desired, the thermally expandable portion can be expanded using a balloon or other mechanical expansion mechanism. Once positioned, the expandable device 100 can be detached from the delivery system, allowing the delivery system to be removed from the patient.

[0127] In any of the foregoing embodiments, if it is necessary to reposition or reshape the thermally expandable portion (e.g., in response to the dynamic environment of the heart and / or the expansion of the valve annulus over time), the thermally expandable portion 114 can be reheated to a second temperature (equal to or higher than A). f To reshape and / or reposition the device.

[0128] Although the foregoing description of the expandable device 100 and the anchoring member 110 is made with reference to aortic valve replacement, it should be understood that the expandable device 100 and / or the anchoring member 110 can also be used for aortic valve repair, mitral valve repair and / or mitral valve replacement.

[0129] Figure 4A-7C Various devices, systems, and methods are shown for delivering thermal energy to the anchoring member 110 (or its thermally expandable portion 114) to transform the thermally expandable portion 114 from its martensitic state to its austenitic or “memory” shape. Figures 4A-4C A method is described for expanding the second portion 114 by infusing warm fluid distal to the anchoring member 110 and / or the thermally expandable portion 114, thereby causing ventricular blood flow to carry the warm fluid proximally through the thermally expandable portion 114 and / or the remainder of the device 100 and along the remainder of the thermally expandable portion 114 and / or the device 100. The fluid can be infused at a second temperature higher than the first temperature.

[0130] Figures 5A-5C A method for expanding a thermo-expandable portion 114 by infusing a fluid (liquid or gas) into an inflatable member 500 located within the lumen of the thermo-expandable portion 114 is described. In some embodiments, the inflatable member 500 may be a balloon, for example. In some embodiments, the inflatable member 500 may expand around the periphery of the thermo-expandable portion 114 (such as an eccentric balloon) by less than 360 degrees, thereby allowing blood flow through the aortic valve annulus during deployment. In those embodiments using an omnidirectional balloon, the balloon can be rapidly inflated and deflated (within seconds) to avoid aortic obstruction. The desired warming effect can be achieved simply by inflating the balloon once with a warm liquid such as saline, or the balloon may have two or more lumens filled from a catheter, allowing the warm saline to be continuously circulated to gradually heat the balloon to a specific desired temperature, warm enough to expand the stent but not enough to damage the valve or surrounding tissue. Alternatively, the balloon may have circuitry to heat the balloon. The balloon may also have a thermistor to measure the temperature of the balloon.

[0131] If the balloon is only used to heat a portion of the stent, the balloon catheter can be steered to press against a wall or other structure, or the balloon catheter can have an expansion bow or strut on the side of the catheter opposite the balloon to help press it against the desired portion of the stent.

[0132] Figures 6A-6CA method for expanding a thermally expandable portion 114 via an expandable heating element 600 is described. The heating element 600 may be made of a plurality of struts. At least a portion of each of these struts may include a conductive material. The heating element 600 may be coupled to a power source 602 located at a proximal external positioning portion of the treatment system via an elongated conductive element 604. When activated, the power source 602 heats the struts of the heating element 600, which radiates heat in the direction of the thermally expandable portion 114. In some embodiments, the entire heating element 600 may be heated and / or conductive. In other embodiments, only the heating element 600 and / or portions of the struts of the heating element 600 may be conductive, and / or portions of the heating element 600 and / or the struts may be insulated.

[0133] The heating element 600 can be configured to expand self-expand or expand in response to thermal energy applied by the power source 602. In the expanded state, the strut can be in a basket-like shape that is generally spherical, cylindrical, quasi-spherical, oval, or other suitable shape. The heating element 600 can expand to contact the thermally expandable portion 114, thereby directly transferring thermal energy to the thermally expandable portion 114 to cause it to expand. When the heating element 600 expands, it can push radially outward against the inner surface of the thermally expandable portion 114, thereby forcing the thermally expandable portion 114 to expand. The heating element 600 may also have insulation inside the strut, so that blood flow does not cool the stent as rapidly as during heating, and so that the heating element does not need to be heated to very high temperatures to avoid a significant increase in stent temperature.

[0134] Figures 7A-7C A method is described for expanding the thermally expandable portion 114 by directly delivering heat to the metal structure of the thermally expandable portion 114. For example, all or part of the thermally expandable portion 114 may be formed of a conductive material, and the anchoring member 110 and / or the thermally expandable portion 114 may be connected to an externally positioned power source 702 via an elongated conductive member 704.

[0135] The structure of the thermally expandable portion 114 of the expandable device 100 disclosed herein is far more robust than that of a typical self-expanding stent. A typical self-expanding stent, when constrained within a catheter at a first temperature (e.g., average body temperature), is intended to return to its fully expanded state. This sustained, long-term outward force on the inner surface of the catheter lumen makes movement of the catheter wall relative to the stent very difficult. Thus, one of the design constraints of a typical self-expanding stent is the sustained outward force. However, the expandable device 100 of this technology is not limited by this constraint and possesses a rigid cross-sectional geometry in the bending plane, a wider strut angle, and so on. Increasing the stiffness of the thermally expandable portion 114 is particularly beneficial because the Young's modulus of martensitic SMA is much lower than that of stainless steel or cobalt-chromium (materials commonly used to make balloon-expandable valves).

[0136] Compared to self-expanding structures, the strut angle in balloon-expandable stent structures can be larger, such as... Figure 9 and 8 The angles 90° and 80° are shown respectively. This is because the balloon-expandable structure undergoes plastic deformation, while the self-expanding structure needs to elastically deform during compression and then rapidly return to its original shape. For example, Figure 10A and 10B Cross sections of struts used in typical self-expanding and balloon-expandable structures are shown, respectively. The moment of inertia depends largely on the width w, but the strain on the material is also significantly affected. To keep the material within its elastic strain limit while increasing overall stiffness, the struts of a typical self-expanding support have a width w significantly smaller than its thickness t. When the expandable device and / or anchoring member is considered to be in a tubular shape, the corresponding thickness t of the strut can be measured along a line orthogonal to and radially extending from the central longitudinal axis of the expandable device and / or anchoring member (e.g., the perpendicular distance between the inner and outer surfaces of the corresponding strut), or the corresponding thickness t of the strut can be measured as a dimension orthogonal to the plane of the expandable device and / or anchoring member when shown as flat. The corresponding width of the strut can be measured as a distance substantially orthogonal to the thickness t.

[0137] like Figure 10B As shown, since the expansion mechanism depends on plastic deformation, the struts of a balloon-expandable structure tend to have a square cross-section. Balloon-expandable stents typically offer greater design freedom to optimize the cross-section to minimize the material used to achieve the desired rigidity. This is because it is not necessary to place the expandable device 100 in its hyperelastic state (when T>A). f When compressed to a low-profile delivery configuration, the martensitic properties of the expandable device 100 of this technology allow for a structural design similar to a balloon-expandable device. Conversely, the expandable device 100 can be compressed in its easily deformable martensitic state and expanded to its austenitic state by applying heat.

[0138] Some additional examples of conventional balloon-expandable stents and self-expandable stents are shown in Figure 11, as are mechanically expandable stents.

[0139] As previously described, the expandable device 100 may include a valve 120 coupled to or configured to be coupled to the anchoring member 110. The valve 120 may include a temporary or permanent valve adapted to prevent blood flow in an upstream direction but allow blood flow in a downstream direction. In some embodiments, the valve 120 may be a replacement valve configured to be disposed in the expandable device 100 (or a component thereof) after the device 100 has been implanted at an autologous valve. The valve 120 may have multiple leaflets and may be made of materials including PTFE, It can be formed from various flexible, impermeable materials, including pyrolytic carbon or other biocompatible materials, or from biological tissues such as pericardial tissue or xenograft valve tissue (e.g., porcine heart tissue or bovine pericardium).

[0140] In some embodiments, the expandable device 100 may optionally include a valve support (not shown) at least partially located within the anchoring member 110. In such embodiments, the artificial valve 120 is coupled to, mounted within, or otherwise carried by the valve support. The device 100 may also include one or more sealing members (not shown) and / or tissue engagement elements (not shown). The sealing members may extend around the inner wall of the anchoring member 110 to prevent perivalvular (e.g., periprosthetic) leakage between the device 100 and autologous tissue and / or between the anchoring member 110 and the valve support (if included). In some embodiments, the tissue engagement element may be a stud disposed on the outer surface of the anchoring member 110 (along one or both of the self-expanding portion 112 and the thermally expandable portion 114) and extending in an angled and / or radially outward direction to engage autologous tissue, and in some embodiments, penetrating the autologous tissue to cause the device 100 to remain or maintain its position at the desired implantation site.

[0141] in conclusion

[0142] While numerous embodiments of the devices, systems, and methods for replacing and / or repairing aortic valves have been described above, this technology can be applied to other applications and / or other scenarios, such as repairing and / or replacing mitral valves or any other autologous valves in mammals. Furthermore, other embodiments besides those described herein are also within the scope of this technology. Additionally, several other embodiments of this technology may have different constructions, components, or procedures than those described herein. Therefore, those skilled in the art will accordingly understand that this technology may have other embodiments with additional elements, or may have embodiments without the above references. Figure 1-1Other embodiments of some of the features shown and described in 1.

[0143] The above detailed description of embodiments of this technology is not intended to be exclusive or to limit the technology to the precise forms disclosed above. Singular or plural terms may also include plural or singular terms, respectively, where context permits. Although specific embodiments and examples of this technology have been described above for illustrative purposes, various equivalent modifications can be made within the scope of this technology, as will be recognized by those skilled in the art. For example, while the steps are presented in a given order, alternative embodiments may perform the steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.

[0144] Furthermore, unless the word “or” is explicitly limited to referring only to a single item that is different from the other items in a list of two or more items, its use in such a list should be interpreted as including (a) any single item in the list, (b) all items in the list, or (c) any combination of items in the list. Additionally, the term “comprising” is used throughout to mean at least the described features (or features), and therefore does not exclude any further number of the same features and / or other features of additional types. It should also be understood that specific embodiments have been described herein for illustrative purposes, but various modifications may be made without departing from the art. Furthermore, while advantages associated with specific embodiments of the art have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments are required to exhibit such advantages to fall within the scope of the art. Therefore, this disclosure and related technologies may cover other embodiments not explicitly shown or described herein.

Claims

1. An anchor member configured to be positioned at a treatment site proximate to an annulus of a native valve of a human patient, the anchor member comprising: an expandable structure comprising a first portion and a second portion, each of the first and second portions having a low-profile state and an expanded state, wherein, when the expandable structure is positioned at the treatment site at body temperature and released from a catheter: the first portion self-expands toward its expanded state and self-expands into apposition with tissue at or near the annulus to secure the anchor member at the treatment site, and the second portion remains in its low-profile state, wherein the second portion of the expandable structure is configured to expand into apposition with tissue at or near the annulus when heated to a second temperature that is higher than the body temperature, and wherein the second portion has a martensite start temperature M s Shape memory alloy greater than or equal to the body temperature is formed.

2. The anchoring member of claim 1, wherein, The shape memory alloy has an austenite completion temperature A that is (a) greater than or equal to the second temperature and (b) greater than body temperature f .

3. The anchoring member of claim 1, wherein, the second temperature is no less than 40°C.

4. The anchoring member of claim 1, wherein, the second temperature is from 37°C to 40°C.

5. The anchoring member of claim 1, wherein, The shape memory alloy has a martensite finish temperature M greater than or equal to the body temperature f and an austenite finish temperature A less than or equal to the second temperature f .

6. The anchoring member of claim 1, wherein, The shape memory alloy has an austenite completion temperature A less than or equal to the second temperature f .

7. The anchoring member of claim 1, wherein, the shape memory alloy has: martensite finish temperature M greater than or equal to the body temperature f and an austenite completion temperature A less than or equal to the second temperature f .

8. The anchoring member of claim 1, wherein, the shape memory alloy has: a martensite finish temperature M less than the body temperature f and an austenite completion temperature A less than or equal to the second temperature f .

9. The anchoring member of claim 1, wherein, The shape memory alloy has an austenite completion temperature A of less than 37°C f .

10. The anchoring member of any one of claims 1 to 9, wherein, the expandable structure is configured so that, when implanted at the annulus of a native valve, the second portion is upstream of the first portion.

11. The anchoring member of any one of claims 1 to 9, wherein, the expandable structure is configured so that, when implanted at or near the annulus of a native aortic valve, (a) at least a portion of the first portion is positioned within the aorta, and (b) at least a portion of the second portion is positioned within the left ventricle.

12. The anchoring member of any one of claims 1 to 9, wherein, the expandable structure is configured so that, when implanted at or near the annulus of a native aortic valve, no portion of the first portion presses outward against the left ventricle.

13. The anchoring member of any one of claims 1 to 9, wherein, the expandable structure is configured so that, when implanted at or near the annulus of a patient's aortic valve, no portion of the first portion is distal to the annulus of the aortic valve.

14. The anchoring member of any one of claims 1 to 9, wherein, when the expandable structure is implanted at or near the annulus of a native aortic valve such that both the first portion and the second portion are expanded and in contact with adjacent tissue, the force with which the first portion presses outward against the adjacent tissue is greater than the force with which the second portion presses outward against the adjacent tissue.

15. The anchoring member of any one of claims 1 to 9, wherein, the second portion is heat-expandable.

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