The left atrial appendage (LAA) is a small organ attached to the left atrium of the heart as a pouch-like extension. In patients suffering from atrial fibrillation, the left atrial appendage may not properly contract with the left atrium, causing stagnant blood to pool within its interior, which can lead to the undesirable formation of thrombi within the left atrial appendage. Thrombi forming in the left atrial appendage may break loose from this area and enter the blood stream. Thrombi that migrate through the blood vessels may eventually plug a smaller vessel downstream and thereby contribute to stroke or heart attack. Clinical studies have shown that the majority of blood clots in patients with atrial fibrillation are found in the left atrial appendage. As a treatment, medical devices have been developed which are positioned in the left atrial appendage and deployed to close off the ostium of the left atrial appendage. Over time, the exposed surface(s) spanning the ostium of the left atrial appendage becomes covered with tissue (a process called endothelization), effectively removing the left atrial appendage from the circulatory system and reducing or eliminating the number of thrombi which may enter the blood stream from the left atrial appendage. A continuing need exists for improved medical devices and methods to control thrombus formation within the left atrial appendage of patients suffering from atrial fibrillation.
This disclosure provides design, material, manufacturing method, and use alternatives for medical devices. An example medical device for occluding the left atrial appendage includes an expandable member including a first balloon defining a first inflation chamber and a second balloon defining a second inflation chamber. Further, the second inflation chamber is positioned adjacent to the first inflation chamber, the first inflation chamber is in fluid communication with the second inflation chamber and the expandable member is designed to shift between a first configuration and a second expanded configuration. Additionally, the first balloon is designed to fill a first region of the left atrial appendage and the second balloon is designed to fill a second region of the left atrial appendage. The medical device also includes a first inflation valve member extending at least partially into the first inflation chamber and the expandable member is configured to expand and seal the opening of the left atrial appendage.
Alternatively or additionally to any of the embodiments above, wherein the expandable member is configured to inflate the first chamber to a first inflation pressure, and wherein the expandable member is configured to inflate the second chamber to a second inflation pressure after the first chamber is inflated to the first inflation pressure.
Alternatively or additionally to any of the embodiments above, further comprising one or more attachment arms positioned adjacent to the expandable member, the one or more attachment arms including one or more projections disposed thereon, wherein the one or more projections are configured to engage a portion of the left atrial appendage wall.
Alternatively or additionally to any of the embodiments above, wherein the expandable member includes a first one-way valve configured to permit an inflation material to flow between the first chamber and the second chamber, wherein the first one-way valve is configured to open when the first chamber is inflated to a first threshold inflation pressure.
Alternatively or additionally to any of the embodiments above, wherein the expandable member further comprises a third inflation chamber in fluid communication with the first inflation chamber, a fourth inflation chamber in fluid communication with the first inflation chamber, and a fifth inflation chamber in fluid communication with the first inflation chamber.
Alternatively or additionally to any of the embodiments above, wherein the second inflation chamber, the third inflation chamber, the fourth inflation chamber and the fifth inflation chamber are spaced circumferentially around the first inflation chamber.
Alternatively or additionally to any of the embodiments above, further comprising a projection configured to anchor the medical device to a target tissue site of the left atrial appendage.
Alternatively or additionally to any of the embodiments above, wherein the projection is configured to shift between a first position and a second extended position, wherein the projection extends radially away from an outer surface of the expandable member in the second extended position.
Alternatively or additionally to any of the embodiments above, wherein the first inflation chamber is positioned proximal to the second inflation chamber.
Alternatively or additionally to any of the embodiments above, further comprising a second inflation valve positioned between the first inflation chamber and the second inflation chamber.
Alternatively or additionally to any of the embodiments above, wherein the expandable member is designed to engage an inflation catheter having a first inflation port and a second inflation port, and wherein the first inflation port extends into the second inflation chamber through the second inflation valve, and wherein the second inflation port is positioned within the first inflation chamber when the first inflation port is positioned within the second inflation chamber.
Alternatively or additionally to any of the embodiments above, wherein the expandable member is configured to inflate the second chamber to a first inflation pressure, and wherein the expandable member is configured to inflate the first chamber to a second inflation pressure after the second chamber is inflated to the first inflation pressure, and wherein the second inflation valve is designed to maintain the first inflation pressure in the second chamber while the first inflation chamber is inflated to the second inflation pressure.
Another medical device for occluding the left atrial appendage includes:
an expandable balloon including an outer surface, a first lobe defining a first inner expansion cavity and a second lobe defining a second inner expansion cavity positioned adjacent to the first inner expansion cavity, wherein the first lobe is designed to expand into a first region of the left atrial appendage and the second lobe is designed to expand into a second region of the left atrial appendage;
a first valve member positioned between the first inner expansion cavity and the second inner expansion cavity, wherein the first valve member is designed to seal the first inner expansion cavity from the second inner expansion cavity;
wherein the expandable balloon is configured to expand and seal the opening of the left atrial appendage.
Alternatively or additionally to any of the embodiments above, wherein the first valve member permits fluid communication between the first inner expansion cavity and the second inner expansion cavity.
Alternatively or additionally to any of the embodiments above, wherein the first chamber is designed to inflate to a first inflation pressure, and wherein the second chamber is designed to inflate to a second inflation pressure after the first chamber is inflated to the first inflation pressure.
Alternatively or additionally to any of the embodiments above, wherein the valve is configured to open when the first chamber is inflated to a first threshold inflation pressure.
Alternatively or additionally to any of the embodiments above, further comprising a second valve member positioned proximal to the first valve member.
Alternatively or additionally to any of the embodiments above, wherein both the first valve member and the second valve member are configured to permit an inflation catheter to extend therethrough.
An example method for sealing the left atrial appendage includes:
advancing an expandable occluder to a position adjacent the left atrial appendage, wherein the expandable occluder includes:
inserting a tubular member into the valve;
passing an inflation media through the tubular member into the valve; and
inflating the expandable member to a first position such that the first lobe is positioned within a first region of the left atrial appendage;
inflating the expandable member to a first position such that the second lobe is positioned within a second region of the left atrial appendage.
Alternatively or additionally to any of the embodiments above, further comprising:
inflating the expandable member to a second position in which the first lobe of the expandable member seals against an inner surface of the first region of the left atrial appendage and the second lobe of the expandable member seals against an inner surface of the second region of the left atrial appendage.
The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures, and Detailed Description, which follow, more particularly exemplify these embodiments
The disclosure may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which:
While aspects of the disclosure are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.
The following description should be read with reference to the drawings, which are not necessarily to scale, wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings are intended to illustrate but not limit the claimed disclosure. Those skilled in the art will recognize that the various elements described and/or shown may be arranged in various combinations and configurations without departing from the scope of the disclosure. The detailed description and drawings illustrate example embodiments of the claimed disclosure. However, in the interest of clarity and ease of understanding, while every feature and/or element may not be shown in each drawing, the feature(s) and/or element(s) may be understood to be present regardless, unless otherwise specified.
For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
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 (e.g., 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” (e.g., 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).
Although some suitable dimensions, ranges, and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges, and/or values may deviate from those expressly disclosed.
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. It is to be noted that in order to facilitate understanding, certain features of the disclosure may be described in the singular, even though those features may be plural or recurring within the disclosed embodiment(s). Each instance of the features may include and/or be encompassed by the singular disclosure(s), unless expressly stated to the contrary. For simplicity and clarity purposes, not all elements of the disclosure are necessarily shown in each figure or discussed in detail below. However, it will be understood that the following discussion may apply equally to any and/or all of the components for which there are more than one, unless explicitly stated to the contrary. Additionally, not all instances of some elements or features may be shown in each figure for clarity.
Relative terms such as “proximal”, “distal”, “advance”, “retract”, variants thereof, and the like, may be generally considered with respect to the positioning, direction, and/or operation of various elements relative to a user/operator/manipulator of the device, wherein “proximal” and “retract” indicate or refer to closer to or toward the user and “distal” and “advance” indicate or refer to farther from or away from the user. In some instances, the terms “proximal” and “distal” may be arbitrarily assigned in an effort to facilitate understanding of the disclosure, and such instances will be readily apparent to the skilled artisan. Other relative terms, such as “upstream”, “downstream”, “inflow”, and “outflow” refer to a direction of fluid flow within a lumen, such as a body lumen, a blood vessel, or within a device.
The term “extent” may be understood to mean a greatest measurement of a stated or identified dimension, unless the extent or dimension in question is preceded by or identified as a “minimum”, which may be understood to mean a smallest measurement of the stated or identified dimension. For example, “outer extent” may be understood to mean a maximum outer dimension, “radial extent” may be understood to mean a maximum radial dimension, “longitudinal extent” may be understood to mean a maximum longitudinal dimension, etc. Each instance of an “extent” may be different (e.g., axial, longitudinal, lateral, radial, circumferential, etc.) and will be apparent to the skilled person from the context of the individual usage. Generally, an “extent” may be considered a greatest possible dimension measured according to the intended usage, while a “minimum extent” may be considered a smallest possible dimension measured according to the intended usage. In some instances, an “extent” may generally be measured orthogonally within a plane and/or cross-section, but may be, as will be apparent from the particular context, measured differently—such as, but not limited to, angularly, radially, circumferentially (e.g., along an arc), etc.
The terms “monolithic” and “unitary” shall generally refer to an element or elements made from or consisting of a single structure or base unit/element. A monolithic and/or unitary element shall exclude structure and/or features made by assembling or otherwise joining multiple discrete elements together.
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 effect the particular 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 below, 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.
For the purpose of clarity, certain identifying numerical nomenclature (e.g., first, second, third, fourth, etc.) may be used throughout the description and/or claims to name and/or differentiate between various described and/or claimed features. It is to be understood that the numerical nomenclature is not intended to be limiting and is exemplary only. In some embodiments, alterations of and deviations from previously-used numerical nomenclature may be made in the interest of brevity and clarity. That is, a feature identified as a “first” element may later be referred to as a “second” element, a “third” element, etc. or may be omitted entirely, and/or a different feature may be referred to as the “first” element. The meaning and/or designation in each instance will be apparent to the skilled practitioner.
The occurrence of thrombi in the left atrial appendage (LAA) during atrial fibrillation may be due to stagnancy of blood pooling in the LAA. The pooled blood may still be pulled out of the left atrium by the left ventricle, however less effectively due to the irregular contraction of the left atrium caused by atrial fibrillation. Therefore, instead of an active support of the blood flow by a contracting left atrium and left atrial appendage, filling of the left ventricle may depend primarily or solely on the suction effect created by the left ventricle. However, the contraction of the left atrial appendage may not be in sync with the cycle of the left ventricle. For example, contraction of the left atrial appendage may be out of phase up to 180 degrees with the left ventricle, which may create significant resistance to the desired flow of blood. Further still, most left atrial appendage geometries are complex and highly variable, with large irregular surface areas and a narrow ostium or opening compared to the depth of the left atrial appendage. For example, in some instances the left atrial appendage may include a bifurcated (e.g., multi-lobe) shape. These aspects as well as others, taken individually or in various combinations, may lead to high flow resistance of blood out of the left atrial appendage.
In an effort to reduce the occurrence of thrombi formation within the left atrial appendage and prevent thrombi from entering the blood stream from within the left atrial appendage, it may be desirable to develop medical devices and/or occlusive implants that close off the left atrial appendage from the heart and/or circulatory system, thereby lowering the risk of stroke due to thromboembolic material entering the blood stream from the left atrial appendage. For example, in some instances it may be desirable to develop medical devices which are designed to close off a bifurcated (e.g., multi-lobe) left atrial appendage. Example medical devices and/or occlusive implants that close off the left atrial appendage are disclosed herein.
The occlusive implant 10 may include an expandable member 16. The expandable member 16 may also be referred to as an expandable balloon 16. The expandable member 16 may be formed from a highly compliant material (e.g., “inflation material”) which permits the expandable member 16 to expand from a first unexpanded (e.g., deflated, collapsed, delivery) configuration to a second expanded (e.g., inflated, delivered) configuration. In some examples, one or more portions of the expandable balloon 16 may be inflated to pressures from about 1 psi to about 200 psi. It can be appreciated that the outer diameter of the occlusive implant 10 may be larger in the expanded configuration versus the unexpanded configuration. Example materials used for the inflation material may be hydrogel beads (or other semi-solid materials), saline, etc.
In some examples, the expandable member 16 may be constructed from silicone or a low-durometer polymer, however, other materials are contemplated. Additionally, the expandable member 16 may be impermeable to blood and/or other fluids, such as water. In some embodiments, the expandable member 16 may include a woven, braided and/or knitted material, a fiber, a sheet-like material, a metallic or polymeric mesh, or other suitable construction. Further, in some embodiments, the expandable member 16 may prevent thrombi (e.g., blood clots, etc.) originating in the left atrial appendage from passing through the occlusive device 10 and into the blood stream. In some embodiments, the occlusive device 10 may promote endothelial growth after implantation, thereby effectively removing the left atrial appendage from the patient's circulatory system. Some suitable, but non-limiting, examples of materials for the occlusive member 10 are discussed below.
Additionally, in some examples each of the second expandable balloon 20, the third expandable balloon 22, the fourth expandable balloon 24 and/or the fifth expandable balloon 26 may be formed as a monolithic structure with the first expandable balloon member 18. In other words, portions of the various balloon members may be shared among the balloon members (e.g., adjacent balloon members may share a balloon wall). However, in other examples one or more of the second expandable balloon 20, the third expandable balloon 22, the fourth expandable balloon 24 and/or the fifth expandable balloon 26 may be separate distinct from one another and/or formed from a different material from each other and/or the first central balloon member 18. Some suitable, but non-limiting, examples of materials for the balloon members are discussed below.
It is contemplated that in some instances the spacing between the adjacent expandable balloons may not be uniform. In some examples, the spacing between the second expandable balloon 20, the third expandable balloon 22, the fourth expandable balloon 24 and/or the fifth expandable balloon 26 may be variable (e.g., non-uniformly spaced) around the circumference of the first expandable balloon 18.
Additionally,
As discussed above,
As stated above, inflation of one or more of the inflation chambers may be accomplished by inserting inflation media through the valve 32. As shown in
The valve 32 may include an inflation lumen 36 which may be designed to allow a secondary medical device to be inserted therethrough. As shown in
It can be appreciated that the O-ring 38 may be formed from a material (e.g., rubber, elastomer, etc.) which permits it to compress radially inwardly. As shown in
As will be discussed in greater detail below, the occlusive member 10 may be coupled to a delivery system in a variety of ways. Further, a component of the delivery system may also function as a secondary medical device utilized to inflate the expandable member 16.
As discussed above, in some examples, one or more of the inflation chambers of the first balloon 18, the second expandable balloon 20, the third expandable balloon 22, the fourth expandable balloon 24 and/or the fifth expandable balloon 26 may be in fluid communication with one another. For example,
The detailed view of
In some examples it may be desirable to design the expandable member 16 such that the one or more anchor members 44 may shift from an unextended configuration when the expandable member 16 is in an unexpanded configuration to an extended configuration when the expandable member 16 is in an expanded configuration. For example,
In some instances, an occlusive implant delivery system 28 may include a delivery catheter 25 which is guided toward the left atrium via various chambers and lumens of the heart (e.g., the inferior vena cava, the superior vena cava, the right atrium, etc.) to a position adjacent the left atrial appendage 60. The delivery system 28 may include a hub member 34 coupled to a proximal region of the delivery catheter 25. The hub member 34 may be manipulated by a clinician to direct the distal end region of the delivery catheter 25 to a position adjacent the left atrial appendage 60. As discussed above, a proximal end of the occlusive device 10 may be configured to releasably attach, join, couple, engage, or otherwise connect to the distal end of the delivery catheter 25. In some embodiments, a proximal end region of the occlusive device 10 may include a threaded insert coupled thereto. In some embodiments, the threaded insert may be configured to and/or adapted to couple with, join to, mate with, or otherwise engage a threaded member disposed at the distal end of the delivery catheter 25. Other means of releasably coupling and/or engaging the proximal end of the occlusive device 10 to the distal end of the delivery catheter 25 are also contemplated. Further, in some examples the delivery catheter 25 may include an inflation lumen (not show) designed to permit inflation media to pass into the occlusive device 10 (as described above). For example, in some examples, the distal end of the delivery catheter 25 may include a needle designed to be inserted through the valve 32 (discussed above).
Further,
Additionally, as described above,
As can be appreciated from
Additionally,
Further, in some examples the valves 170 may be designed to open after a threshold inflation pressure has been attained in the first inflation chamber. For example, in some instances, when the first inflation chamber 121 is filled with inflation material to a threshold inflation pressure, one or more of the valves 170 may open, thereby permitting the inflation material to pass through the valves 170 into the second inflation chamber 123 and/or the fourth inflation chamber 127.
As shown in
While the above example illustrates that O-rings 238 may be utilized to seal the first valve 232 and/or the second valve 276, this is not intended to me limiting. Rather, it is contemplated that, in some examples, the O-rings 238, 274a, 274b may not be necessary to seal the first valve 232 and/or the second valve 276. Rather, in some examples, the first valve 232 and/or the second valve 276 may include sufficient radially inward compressive strength to seal around an inflation catheter 278 inserted therethrough.
Additionally,
However, in other examples, the inflation chamber of the first balloon 224 may be inflated in sequence with the inflation chamber of the second balloon 220. For example, the inflation chamber 220 of the second balloon may be inflated via the lumen 290 followed by inflation of the inflation chamber of the first balloon 224. Further yet, it can be appreciated that the inflation chamber 220 of the second balloon may be inflated via lumen 290 and port 280, whereby a clinician may then withdraw the inflation device 278 proximally through valve 272 such that the O-rings 274a, 274b collapse and seal the valve 272. After the valve 272 is seal (and the inflation chamber of the second balloon is pressurized) the clinician may continue to inject inflation material through the lumen 290 and port 280 to inflate the inner chamber of the first balloon 224. After the first balloon 224 is inflated, the clinician may remove the inflation catheter 278 from the first valve 232, thereby sealing the inner chamber of the first balloon 224.
It can be appreciated that this inflation technique may permit the first balloon 224 and the second balloon 220 may be inflated to different pressures. It can be further appreciated that the first balloon 224 and the second balloon 220 may be inflated with different materials. For example, in some examples the first balloon 224 may be inflated with saline while the second balloon 220 may be inflated with hydrogel. In other examples, the first balloon 224 may be inflated with hydrogel while the second balloon 220 may be inflated with saline. Additionally, other inflation materials are contemplated, as described below.
While
As shown in
Additionally,
Additionally,
As shown in
Additionally,
Additionally,
The occlusive implant 510 may include an expandable member 516. The expandable member 516 may also be referred to as an expandable balloon 516. The expandable member 516 may be formed from a highly compliant material (e.g., “inflation material”) which permits the expandable member 516 to expand from a first unexpanded (e.g., deflated, collapsed, delivery) configuration to a second expanded (e.g., inflated, delivered) configuration. In some examples, one or more portions of the expandable balloon 516 may be inflated to pressures from about 1 psi to about 200 psi. It can be appreciated that the outer diameter of the occlusive implant 510 may be larger in the expanded configuration versus the unexpanded configuration. Example materials used for the inflation material may be hydrogel beads (or other semi-solid materials), saline, etc.
In some examples, the expandable member 516 may be constructed from silicone or a low-durometer polymer, however, other materials are contemplated. Additionally, the expandable member 516 may be impermeable to blood and/or other fluids, such as water. In some embodiments, the expandable member 516 may include a woven, braided and/or knitted material, a fiber, a sheet-like material, a metallic or polymeric mesh, or other suitable construction. Further, in some embodiments, the expandable member 516 may prevent thrombi (e.g., blood clots, etc.) originating in the left atrial appendage from passing through the occlusive device 510 and into the blood stream. In some embodiments, the occlusive device 510 may promote endothelial growth after implantation, thereby effectively removing the left atrial appendage from the patient's circulatory system.
Additionally,
The materials that can be used for the various components of the occlusive implant 10 (and variations, systems or components thereof disclosed herein) and the various elements thereof disclosed herein may include those commonly associated with medical devices. For simplicity purposes, the following discussion makes reference to the occlusive implant 10 (and variations, systems or components disclosed herein). However, this is not intended to limit the devices and methods described herein, as the discussion may be applied to other elements, members, components, or devices disclosed herein.
In some embodiments, the occlusive implant 10 (and variations, systems or components thereof disclosed herein) may be made from a metal, metal alloy, polymer (some examples of which are disclosed below), a metal-polymer composite, ceramics, combinations thereof, and the like, or other suitable material. Some examples of suitable metals and metal alloys include stainless steel, such as 444V, 444L, and 314LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic and/or super-elastic nitinol; other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R44035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g., UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R44003 such as ELGILOY®, PHYNOX®, and the like); platinum enriched stainless steel; titanium; platinum; palladium; gold; combinations thereof; and the like; or any other suitable material.
As alluded to herein, within the family of commercially available nickel-titanium or nitinol alloys, is a category designated “linear elastic” or “non-super-elastic” which, although may be similar in chemistry to conventional shape memory and super elastic varieties, may exhibit distinct and useful mechanical properties. Linear elastic and/or non-super-elastic nitinol may be distinguished from super elastic nitinol in that the linear elastic and/or non-super-elastic nitinol does not display a substantial “superelastic plateau” or “flag region” in its stress/strain curve like super elastic nitinol does. Instead, in the linear elastic and/or non-super-elastic nitinol, as recoverable strain increases, the stress continues to increase in a substantially linear, or a somewhat, but not necessarily entirely linear relationship until plastic deformation begins or at least in a relationship that is more linear than the super elastic plateau and/or flag region that may be seen with super elastic nitinol. Thus, for the purposes of this disclosure linear elastic and/or non-super-elastic nitinol may also be termed “substantially” linear elastic and/or non-super-elastic nitinol.
In some cases, linear elastic and/or non-super-elastic nitinol may also be distinguishable from super elastic nitinol in that linear elastic and/or non-super-elastic nitinol may accept up to about 2-5% strain while remaining substantially elastic (e.g., before plastically deforming) whereas super elastic nitinol may accept up to about 8% strain before plastically deforming. Both of these materials can be distinguished from other linear elastic materials such as stainless steel (that can also be distinguished based on its composition), which may accept only about 0.2 to 0.44 percent strain before plastically deforming.
In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy is an alloy that does not show any martensite/austenite phase changes that are detectable by differential scanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA) analysis over a large temperature range. For example, in some embodiments, there may be no martensite/austenite phase changes detectable by DSC and DMTA analysis in the range of about −60 degrees Celsius (° C.) to about 120° C. in the linear elastic and/or non-super-elastic nickel-titanium alloy. The mechanical bending properties of such material may therefore be generally inert to the effect of temperature over this very broad range of temperature. In some embodiments, the mechanical bending properties of the linear elastic and/or non-super-elastic nickel-titanium alloy at ambient or room temperature are substantially the same as the mechanical properties at body temperature, for example, in that they do not display a super-elastic plateau and/or flag region. In other words, across a broad temperature range, the linear elastic and/or non-super-elastic nickel-titanium alloy maintains its linear elastic and/or non-super-elastic characteristics and/or properties.
In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy may be in the range of about 50 to about 60 weight percent nickel, with the remainder being essentially titanium. In some embodiments, the composition is in the range of about 54 to about 57 weight percent nickel. One example of a suitable nickel-titanium alloy is FHP-NT alloy commercially available from Furukawa Techno Material Co. of Kanagawa, Japan. Other suitable materials may include ULTANIUM™ (available from Neo-Metrics) and GUM METAL™ (available from Toyota). In some other embodiments, a superelastic alloy, for example a superelastic nitinol can be used to achieve desired properties.
In at least some embodiments, portions or all of the occlusive implant 10 (and variations, systems or components thereof disclosed herein) may also be doped with, made of, or otherwise include a radiopaque material. Radiopaque materials are understood to be materials capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids a user in determining the location of the occlusive implant 10 (and variations, systems or components thereof disclosed herein). Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with a radiopaque filler, and the like. Additionally, other radiopaque marker bands and/or coils may also be incorporated into the design of the occlusive implant 10 (and variations, systems or components thereof disclosed herein). to achieve the same result.
In some embodiments, a degree of Magnetic Resonance Imaging (MRI) compatibility is imparted into the occlusive implant 10 (and variations, systems or components thereof disclosed herein). For example, the occlusive implant 10 (and variations, systems or components thereof disclosed herein) and/or components or portions thereof, may be made of a material that does not substantially distort the image and create substantial artifacts (e.g., gaps in the image). Certain ferromagnetic materials, for example, may not be suitable because they may create artifacts in an MRI image. The occlusive implant 10 (and variations, systems or components disclosed herein) or portions thereof, may also be made from a material that the MRI machine can image. Some materials that exhibit these characteristics include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R44003 such as ELGILOY®, PHYNOX®, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R44035 such as MP35-N® and the like), nitinol, and the like, and others.
In some embodiments, the occlusive implant 10 (and variations, systems or components thereof disclosed herein) and/or portions thereof, may be made from or include a polymer or other suitable material. Some examples of suitable polymers may include copolymers, polyisobutylene-polyurethane, polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example, DELRIN® available from DuPont), polyether block ester, polyurethane (for example, Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene/poly(alkylene ether) phthalate and/or other polyester elastomers such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example available under the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly paraphenylene terephthalamide (for example, KEVLAR®), polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS 50A), polycarbonates, ionomers, polyurethane silicone copolymers (for example, ElastEon® from Aortech Biomaterials or ChronoSil® from AdvanSource Biomaterials), biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. In some embodiments, the sheath can be blended with a liquid crystal polymer (LCP). For example, the mixture can contain up to about 6 percent LCP.
In some embodiments, the occlusive implant 10 (and variations, systems or components thereof disclosed herein) may include a textile material. Some examples of suitable textile materials may include synthetic yarns that may be flat, shaped, twisted, textured, pre-shrunk or un-shrunk. Synthetic biocompatible yarns suitable for use in the present disclosure include, but are not limited to, polyesters, including polyethylene terephthalate (PET) polyesters, polypropylenes, polyethylenes, polyurethanes, polyolefins, polyvinyls, polymethylacetates, polyamides, naphthalene dicarboxylene derivatives, natural silk, and polytetrafluoroethylenes. Moreover, at least one of the synthetic yarns may be a metallic yarn or a glass or ceramic yarn or fiber. Useful metallic yarns include those yarns made from or containing stainless steel, platinum, gold, titanium, tantalum or a Ni—Co—Cr-based alloy. The yarns may further include carbon, glass or ceramic fibers. Desirably, the yarns are made from thermoplastic materials including, but not limited to, polyesters, polypropylenes, polyethylenes, polyurethanes, polynaphthalenes, polytetrafluoroethylenes, and the like. The yarns may be of the multifilament, monofilament, or spun-types. The type and denier of the yarn chosen may be selected in a manner which forms a biocompatible and implantable prosthesis and, more particularly, a vascular structure having desirable properties.
In some embodiments, the occlusive implant 10 (and variations, systems or components thereof disclosed herein) may include and/or be treated with a suitable therapeutic agent. Some examples of suitable therapeutic agents may include anti-thrombogenic agents (such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethylketone)); anti-proliferative agents (such as enoxaparin, angiopeptin, monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid); anti-inflammatory agents (such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine); antineoplastic/antiproliferative/anti-mitotic agents (such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors); anesthetic agents (such as lidocaine, bupivacaine, and ropivacaine); anti-coagulants (such as D-Phe-Pro-Arg chloromethyl keton, an RGD peptide-containing compound, heparin, anti-thrombin compounds, platelet receptor antagonists, anti-thrombin antibodies, anti-platelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors, and tick antiplatelet peptides); vascular cell growth promoters (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional activators, and translational promoters); vascular cell growth inhibitors (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin); cholesterol-lowering agents; vasodilating agents; and agents which interfere with endogenous vascoactive mechanisms.
While the discussion above is generally directed toward an occlusive implant for use in the left atrial appendage of the heart, the aforementioned features may also be useful in other types of medical implants where a fabric or membrane is attached to a frame or support structure including, but not limited to, implants for the treatment of aneurysms (e.g., abdominal aortic aneurysms, thoracic aortic aneurysms, etc.), replacement valve implants (e.g., replacement heart valve implants, replacement aortic valve implants, replacement mitral valve implants, replacement vascular valve implants, etc.), and/or other types of occlusive devices (e.g., atrial septal occluders, cerebral aneurysm occluders, peripheral artery occluders, etc.). Other useful applications of the disclosed features are also contemplated.
It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the disclosure. This may include, to the extent that it is appropriate, the use of any of the features of one example embodiment being used in other embodiments. The disclosure's scope is, of course, defined in the language in which the appended claims are expressed.
This application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Application Ser. No. 62/695,985, filed Jul. 10, 2018, the entirety of which is incorporated herein by reference.
Number | Date | Country | |
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62695985 | Jul 2018 | US |