Patent Application
20220354646
The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to medical devices, systems, and methods for annuloplasty and other cardiac treatment techniques.
Mitral insufficiency (MI) (also referred to as mitral regurgitation or mitral incompetence) is a form of heart disease where the mitral annulus dilates excessively and the valve leaflets no longer effectively close, or coapt, during systolic contraction. Regurgitation of blood occurs during ventricular contraction and cardiac output decreases as a result.
Mitral valve annuloplasty is a procedure which seeks to reduce a dilated valve annulus to regain mitral valve competence. Surgical annuloplasty involves surgical implantation of an annuloplasty ring around a valve annulus to restore it approximately to its native configuration. Annuloplasty surgery is an invasive and time-consuming procedure that poses risks of morbidity and mortality due to stroke, thrombosis, heart attack, and extended recovery time.
Endoluminal annuloplasty is a less invasive annuloplasty method that transluminally navigates an implant to a mitral valve treatment site. Endoluminal implants may include collars, rings, expandable frames, or other structures that are affixed to the annular ring during deployment using anchors.
The efficacy of an implant may be impaired due to the chronic stress experienced by the anchors from the palpitation of the cardiac muscle. It would be desirable to maintain implant integrity by minimizing the impact of chronic stress upon implant anchors.
Embodiments of the present disclosure relate to an anchor configured to increase anchor interaction with one or both of cardiac tissue and the implant to maintain implant integrity. In accordance with some aspects of the present disclosure, the anchor shaft is configured to present an element that increases surface area for contact with tissue in which the anchor shaft is inserted, such that the anchor shaft presents a surface area greater than the surface area presented by prior art anchor shafts, to the tissue to be engaged by the anchor shaft. In some embodiments, the anchor shaft is in a helical configuration to form a helical anchor. The increase in surface area presented by the anchor shaft for engagement with tissue may be achieved in a variety of manners as disclosed herewith. In some embodiments, the cross-sectional shape of the shaft is modified to present a surface with a greater surface area for contact with tissue than previously provided. In some embodiments, the cross-sectional shape of the shaft has more than one side or surface contacting the tissue. In some embodiments, the cross-sectional shape is canted or angled with respect to the longitudinal axis or central axis or translation axis of the anchor to provide more than one side or surface for engagement with tissue.
In various embodiments, one or both of the width or the thickness of the anchor shaft may vary over the length of the anchor shaft. The width or the thickness of the anchor shaft may reduce at least once towards the distal tip of the anchor shaft.
A central lumen having a length along the central axis and defined by the anchor shaft may vary in diameter along the length of the central lumen. The diameter of the central lumen may reduce at least once towards the distal tip of the anchor shaft.
The anchor may further (or alternatively) include a retention feature disposed on the anchor shaft. The width of the anchor shaft may be angularly oriented relative to the central axis. At least one opening may extend through the width of the anchor shaft. The retention feature may include one or more barbs disposed on the anchor shaft. The retention feature may be configured to retain the anchor within an anchor housing of an implant. The width of the retention feature may be oriented parallel to the central axis, and the at least one opening may extend perpendicularly to central axis through the width of the anchor shaft. The at least one opening may be one of a plurality of openings disposed on the anchor shaft, each opening disposed on or through a surface of the anchor shaft, or both. The anchor may include at least one filler disposed in the at least one opening, the at least one filler including a drug, an extracellular matrix, a fibrous matrix, a mesh, a braid, or some combination thereof. The anchor may be formed of a laser cut hypo tube.
According to another aspect an implant includes a frame configured for a valve annulus and a plurality of anchors, coupled to the frame. Each anchor may include a proximal head, a distal tip, and an anchor shaft disposed between the proximal head and the distal tip, the anchor shaft having a width and a thickness. In some embodiments, the thickness is different from the width. In some embodiments, the anchor shaft presents more than one surface for engagement with the tissue. The anchor shaft may be helically disposed about a central axis extending from the proximal head to the distal tip of the anchor and include a retention feature configured to secure the anchor shaft to one or both of the frame and the valve annulus.
In various embodiments, one or both of the width and the thickness of the anchor shaft may vary at least once over a length of the anchor shaft. The retention feature may include a surface texture of the anchor shaft, a protuberance on the anchor shaft, or an opening on or through the anchor shaft, or some combination thereof. The frame may include an expandable frame having adjacent struts joined at a distal end of the adjacent struts, the adjacent struts configured to support at least one anchor, and where the retention feature of the at least one anchor retains the at least one anchor within the distal end of the adjacent struts.
According to another aspect a method of annuloplasty includes the steps of positioning an implant proximate a valve annulus. The implant may include a frame including a plurality of struts joined at an apex, an anchor housing disposed on the apex, and an anchor supported by the anchor housing. The anchor may include an anchor shaft having a width and a thickness, the thickness different from the width, and at least one backout feature configured to inhibit proximal translation of the anchor shaft through the anchor housing. The method may include the steps of driving the anchor through the anchor housing of the implant into annular tissue to expose the at least one backout feature to tissue and releasing the anchor, where the at least one backout feature interacts with at least one of the implant and the tissue to inhibit proximal translation of the anchor shaft through the anchor housing.
In one embodiment, the at least one backout feature may include a surface texture of the anchor shaft, a protuberance on the anchor shaft, or an opening on or through the anchor shaft, or some combination thereof. In one embodiment, one or both of the width and the thickness of the anchor shaft varies at least once over a length of the anchor shaft.
Non-limiting embodiments of the present disclosure are described by way of examples with reference to the accompanying figures, which are schematic and not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:
Stresses and strains resulting from the palpatory motion of the heart may adversely affect the integrity of implant anchoring over time. For example, anchor affixation may degrade, and the anchor may become partially or fully released from its original anchoring location. Such anchor backout may impair the efficacy of the implant. To overcome these and other issues, an anchor as disclosed herein is configured to maximize the contact surface area between an anchor and exposed tissue to improve integration between the tissue and the anchor. Accordingly, in various embodiments, the anchor may be configured such that a width differs from a thickness of the anchor. In some embodiments the anchor may be generally ribbon shaped. In various embodiments, the ribbon may be helically shaped, may vary in width and/or thickness along its extent, may include holes, features or textures that aid in tissue integration, or a combination of any one or more such attributes.
For example, in some embodiments, the anchor may include retention features that are configured to promote tissue interaction and/or ingrowth with the anchor to improve tissue/anchor interaction and as a result anchor retention. In some embodiments, the retention features may also improve retention of the anchor within the implant in the presence of chronic palpatory forces.
These and other beneficial aspects of the disclosed anchor are now described below. It should be noted that although embodiments of the present disclosure may be described with specific reference to mitral valves, the principles disclosed herein may be readily adapted to facilitate reconstruction of any valve annulus, for example including a tricuspid valve annulus and/or may similarly benefit any other dilatation, valve incompetency, valve leakage and other similar heart failure conditions.
As used herein, the term “distal” refers to the end farthest away from the medical professional when introducing a medical device into a patient, while the term “proximal” refers to the end closest to the medical professional when introducing a medical device into a patient.
The anchor shaft 115 is coupled to the anchor head 105. In some embodiments, the anchor head may be bonded to or integral with the anchor shaft 115. The anchor shaft 115 comprises a length L, a width W, and a thickness T. In contrast to prior art anchors, many of which are formed from a rounded wire, the anchor shaft 115 is advantageously configured to maximize contact surface area with tissue, and thus comprises a width W that exceeds the thickness T of the shaft 115. The resulting ‘ribbon’ shaped anchor 100 is provided. In various embodiments, the relatively wider width of a ribbon surface is oriented for maximal tissue contact. By maximizing tissue contact, the opportunity for integration between the anchor 100 and surrounding tissue is improved, and anchor migration and backout may be reduced.
In various embodiments, the surface area of the anchor contacting the tissue may be increased by other modifications to the cross-sectional shape of the turns of the anchor. For instance, the anchor shaft may have a shape (with three or more sides) with more than one side or surface thereof presented for engagement with tissue. For instance, in an anchor with a quadrilateral shape or cross-section, each turn of the helical tissue anchor may be canted to present two sides of the quadrilateral shape to the tissue. Such canted configuration or effect may be formed by a laser cutting process applied to the material, e.g., tube or shaft, from which the anchor is formed. An example of an anchor formed by a laser cutting process is shown in
According to one aspect, an anchor such as that disclosed herein for use in a cardiac cavity may be formed from a suitable biocompatible metal alloy such as stainless steel, cobalt chromium, platinum iridium, nickel titanium, other suitable materials, or combinations thereof. The distal end 120 of the shaft 115 may be sharpened at its distal point, or leading turn, so as to facilitate penetration into the cardiac tissue. Each anchor 100 may be from about ten to about fifteen millimeters (mm) in total axial length. In some embodiments, the anchors 100 may be shorter or longer than ten to fifteen millimeters (mm) in total axial length. By “total” axial length it is meant the axial length of the anchor 100 from the end of the distal penetrating tip 120 to the opposite, proximal end of the head 105. The Length L of the shaft 115 may be from about six to about twelve millimeters (mm). In some embodiments, the shaft 115 may be shorter or longer than six to twelve millimeters (mm) in axial length. The anchor head 105 and/or other non-helical portions of the anchor 100 may be from about three to about four millimeters (mm) in axial length. In some embodiments, the anchor head 105 and/or other non-helical portions may be shorter or longer than three to four millimeters (mm) in axial length.
In some embodiments, the shaft 115 may be laser cut from a stainless steel hypo tube formed of full hard temper, type 304 stainless steel, resulting in an anchor having a central lumen extending therethrough defined by the turns of the helical anchor. In other embodiments, the anchor 100 may be cut from a stainless steel sheet and shaped to obtain the helical anchor configuration. In some embodiments, the thickness T of the stainless steel sheet and/or hypo tube may range from between 0.020 mm to about 2 mm In some embodiments, the thickness T may increase, decrease and/or otherwise vary along the length L of the anchor shaft 110. In some embodiments, the inner diameter (ID) of the central lumen may range from between 1 mm to about 3 mm. In some embodiments, the inner diameter (ID) may increase, decrease or otherwise vary along the length L of the anchor shaft 115.
In some embodiments, the width W of the anchor may range from between 0.5 mm to about 2 mm. In some embodiments, the width W may increase, decrease or otherwise vary along the length L of the anchor shaft 115. In general, the width is selected to maximize the surface area contact between the anchor and neighboring tissue to secure the anchor to the tissue. Although the anchor shaft 115 is shown to include five turns (T1-T5) (“pitch”), in various embodiments, the number of turns of the anchor may be from about ten per inch to about thirty-six per inch. In some embodiments the distal tip 120 as well as at least a portion of edges 111 of the anchor 110 are sharpened and/or beveled to facilitate tissue engagement.
The anchor 300 is shown constructed of a ribbon like material that varies in thickness and/or width as the shaft extends distally. Thus, turn 330, which is more proximally positioned, includes a wider surface area than turn 333. Such an arrangement may facilitate the initial driving of the anchor into tissue, which reduces the opportunity for anchor backout.
According to various embodiments, the anchors may be configured with one or more retention features. The retention features may be configured for similar or different purposes. For example, the retention features may be configured to increase interaction between the anchor and the tissue to aid securing of the anchor to the treatment site. The retention features may further be configured to decrease the potential that the anchor may be released from the implant.
The anchor 300 of
Holes such as hole 304a and 304b may be holes that are at least partially cut into and/or through the ribbon surface. In some embodiments, the holes may be shaped and/or sized to promote tissue ingrowth. For example, the holes may comprise pores with a diameter of at least about 20 μm, or at least about 50 μm, or at least about 75 μm, and a diameter of at most about 1000 μm, or at most about 750 μm, or at most about 500 μm. For example, pores with a diameter in the range of 700 μm+/1 15%, or 100-500 μm, or 100-250 μm may be used. The pores may extend through the ribbon anchor or partially through the ribbon anchor. In some embodiments, one or more of the pores and/or holes may be filled or partially filled with a filler such as a drug, a fibrous matrix, an extracellular matrix (ECM), a mesh, a braid, or other mechanism, or combination thereof to promote tissue ingrowth. In various embodiments, the numbers of holes/pores may vary along the extent of the anchor shaft 320. In some embodiments, the number of pores may vary based on the pitch and location of a particular point on the anchor, for example, as shown in
One advantage of the anchors disclosed herein is their ease of manufacturability. As mentioned previously, in one embodiment, the anchors may be laser cut from hypo tubes. Alternatively, as shown in
It should be noted that although the anchors disclosed herein have been described as generally ribbon shaped, the disclosure is not so limited. For example,
Accordingly, an improved anchor design having increased surface area to improve tissue integration has been shown and described. In various embodiments the anchors may be configured to vary in one or more of width, thickness, pitch and diameter along the extent of the anchor. The anchors may be configured with retention features configured to improve tissue adherence as well as to retain the anchors in the implant in the event of backout. It will be appreciated that the anchors may be used in a variety of cardiac implant devices, including but not limited to annular rings which are anchored into location and/or those disclosed in
Thus, an improved anchor design having increased surface area to improve tissue integration has been shown and described. Although embodiments of the present disclosure may be described with specific reference to medical devices and systems (e.g., transluminal devices inserted through a femoral vein or the like) for selective access to heart tissue, it should be appreciated that such medical devices and systems may be used in a variety of medical procedures that require anchoring to heart tissue. The disclosed medical devices and systems may also be inserted via different access points and approaches, e.g., percutaneously, endoscopically, laparoscopically, or combinations thereof.
As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises” and/or “comprising,” or “includes” and/or “including” when used herein, specify the presence of stated features, regions, steps, elements and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and/or groups thereof.
As used herein, the conjunction “and” includes each of the structures, components, features, or the like, which are so conjoined, unless the context clearly indicates otherwise, and the conjunction “or” includes one or the others of the structures, components, features, or the like, which are so conjoined, singly and in any combination and number, unless the context clearly indicates otherwise.
All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about,” in the context of numeric values, generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure. Other uses of the term “about” (i.e., in a context other than numeric values) may be assumed to have their ordinary and customary definition(s), as understood from and consistent with the context of the specification, unless otherwise specified. The recitation of numerical ranges by endpoints includes all numbers within that range, including the endpoints (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
It is noted that references in the specification to “an embodiment,” “some embodiments,” “other embodiments,” etc., indicate that the embodiment(s) described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described, unless clearly stated to the contrary. That is, the various individual elements described herein, even if not explicitly shown in a particular combination, are nevertheless contemplated as being combinable or arrangeable with each other to form other additional embodiments or to complement and/or enrich the described embodiment(s), as would be understood by one of ordinary skill in the art.
All of the devices and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the devices and methods of this disclosure have been described in terms of preferred embodiments, it may be apparent to those of skill in the art that variations can be applied to the devices and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the disclosure. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the disclosure as defined by the appended claims.
The present application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application 62/882,027, filed Aug. 2, 2019, which application is incorporated herein by reference in its entirety for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US20/44740 | 8/3/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62882027 | Aug 2019 | US |
