DEVICES AND METHODS FOR OCCLUSION OF VASCULAR SYSTEM ABNORMALITIES

Abstract

Described herein is a medical device for treating a target site, the medical device including, a proximal end including a disc and a distal end including a lobe. The disc and the lobe are connected by a connecting member. The lobe includes a proximal portion defining a proximal surface of the lobe, a distal portion defining a distal surface of the lobe, and a middle portion connecting and extending between the proximal portion and the distal portion. A first transition between the proximal portion and the middle portion is curved, and a second transition between the middle portion and the distal portion is curved. The medical device also includes a plurality of stabilizing wires coupled to the lobe at a radially outer surface of the middle portion, each stabilizing wire including a hook portion extending radially outward from the at least one lobe.

Claims

1. A method for occluding a left atrial appendage (LAA), the method comprising: providing an occluder that has, when in a radially uncompressed condition, (i) a disc at a proximal end of the occluder, (ii) a lobe at a distal end of the occluder, the lobe including a proximal surface that transitions into a middle portion at a first transition and a distal portion that transitions into the middle portion at a second transition, (iii) a connecting member that connects the disc to the lobe, and (iv) a plurality of stabilizing wires coupled to the lobe at the middle portion, each stabilizing wire having a hook portion extending radially outward from the lobe and pointing toward the disc; while the occluder is in a reduced delivery condition within a delivery catheter, advancing the occluder toward the LAA; deploying the lobe of the occluder from the delivery catheter so that the lobe self-expands into the LAA and so that the lobe has a deployed condition in which radial compression is applied to the lobe by tissue of the LAA, the radial compression causing the proximal surface of the lobe and the distal surface of the lobe to bow outwardly in a longitudinal direction, while the middle portion resists bowing radially inwardly from the applied radial compression.

2. The method of claim 1, wherein in the radially uncompressed condition, the middle portion is linear between the first transition and the second transition.

3. The method of claim 1, wherein in the radially uncompressed condition, the hook portion has a first angle with respect to the longitudinal direction.

4. The method of claim 3, wherein when the lobe has the deployed condition, the hook portion maintains the first angle with respect to the longitudinal direction.

5. The method of claim 1, wherein after deploying the lobe of the occluder from the delivery catheter, the hook portions of the plurality of stabilizing wires engage with the tissue of the LAA to help retain the occluder within the LAA.

6. The method of claim 5, further comprising deploying the disc from the delivery catheter after deploying the lobe from the delivery catheter.

7. The method of claim 6, wherein deploying the disc from the delivery catheter includes allowing the disc to self-expand into a deployed condition.

8. The method of claim 7, wherein when the disc is in the deployed condition, the disc abuts a wall of the heart surrounding an opening of the LAA.

9. The method of claim 8, wherein when the disc is in the deployed condition, the disc has a diameter that is larger than a diameter of the opening of the LAA.

10. The method of claim 9, further comprising disconnecting a delivery cable from the disc after the disc is in the deployed condition to fully deploy the occluder.

11. The method of claim 1, wherein the second transition is curved.

12. The method of claim 11, wherein the second transition has a radius of curvature between 0.001 inches and 0.150 inches.

13. The method of claim 12, wherein the second transition has a radius of curvature between 0.025 inches and 0.150 inches.

14. The method of claim 13, wherein the second transition has a radius of curvature between 0.075 inches and 0.125 inches.

15. The method of claim 11, wherein the first transition is curved.

16. The method of claim 15, wherein the first transition has a radius of curvature between 0.001 inches and 0.150 inches.

17. The method of claim 16, wherein the first transition has a radius of curvature between 0.025 inches and 0.150 inches.

18. The method of claim 17, wherein the first transition has a radius of curvature between 0.075 inches and 0.125 inches.

19. The method of claim 11, wherein the first transition is blunt.

20. The method of claim 19, wherein the first transition is approximately 90 degrees.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 illustrates a known medical device;

[0011] FIGS. 2A-2C are a schematic diagram of the known medical device shown in FIG. 1 under radial compression;

[0012] FIG. 3 is a schematic diagram of a delivery system in accordance with the present disclosure;

[0013] FIG. 4 illustrates a side view of an exemplary embodiment of a medical device including a rounded lobe, in accordance with the present disclosure;

[0014] FIGS. 5A and 5B are a schematic diagram of the medical device shown in FIG. 4 under radial compression;

[0015] FIG. 6 is an expanded view of the medical device shown in FIG. 4 under radial compression;

[0016] FIG. 7 is a flow diagram of an exemplary method of using a medical device to occlude a target site, in accordance with the present disclosure; and

[0017] FIG. 8 is a flow diagram of an exemplary method of fabricating a medical device to occlude a target site, in accordance with the present disclosure.

[0018] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. It is understood that that Figures are not necessarily to scale.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0019] The present disclosure relates generally to medical devices that are used in the human body. Specifically, the present disclosure provides medical devices including occlusion devices having a rounded lobe at a distal end thereof. The rounded shape of the lobe enables the lobe to maintain a more consistent shape in its use range (e.g., under various radial compression forces experienced while the medical device is deployed at a target site). Rounding the edges of the lobe, as described herein, creates a bending moment in a circumferential face of the lobe, such that this circumferential face resists becoming concave. In the exemplary embodiment, the medical device further includes stabilizing wires coupled to the surface of and extending radially outward from the lobe. When the lobe maintains a non-concave shape during sinus compressions, the stabilizing wires maintain a more consistent angle, which in turn maintains an optimal engagement between the stabilizing wires and the adjacent tissue.

[0020] Accordingly, the occlusion devices of the present disclosure decrease the motion of the stabilizing wires, which enables the medical device to minimize the retraction of the stabilizing wires from tissue when the device is deployed at the target site.

[0021] The disclosed embodiments may lead to more consistent and improved patient outcomes. It is contemplated, however, that the described features and methods of the present disclosure as described herein may be incorporated into any number of systems as would be appreciated by one of ordinary skill in the art based on the disclosure herein.

[0022] Although the exemplary embodiment of the medical device is described as treating a target site including a left atrial appendage (LAA), it is understood that the use of the term target site is not meant to be limiting, as the medical device may be configured to treat any target site, such as an abnormality, a vessel, an organ, an opening, a chamber, a channel, a hole, a cavity, or the like, located anywhere in the body. The term vascular abnormality, as used herein is not meant to be limiting, as the medical device may be configured to bridge or otherwise support a variety of vascular abnormalities. For example, the vascular abnormality could be any abnormality that affects the shape of the native lumen, such as an atrial septal defect, a lesion, a vessel dissection, or a tumor. Embodiments of the medical device may be useful, for example, for occluding a patent foramen ovalis (PFO), atrial septal defect (ASD), ventricular septal defect (VSD), or patent ductus arteriosus (PDA), as noted above. Furthermore, the term lumen is also not meant to be limiting, as the vascular abnormality may reside in a variety of locations within the vasculature, such as a vessel, an artery, a vein, a passageway, an organ, a cavity, or the like. As used herein, the term proximal refers to a part of the medical device or the delivery device that is closest to the operator, and the term distal refers to a part of the medical device or the delivery device that is farther from the operator at any given time as the medical device is being delivered through the delivery device. In addition, the terms deployed and implanted may be used interchangeably herein.

[0023] Some embodiments of the present disclosure provide an improved percutaneous catheter directed intravascular occlusion device for use in the vasculature in patients' bodies, such as blood vessels, channels, lumens, a hole through tissue, cavities, and the like, such as an atrial septal defect. Other physiologic conditions in the body occur where it is also desirous to occlude a vessel or other passageway to prevent blood flow into or therethrough. These device embodiments may be used anywhere in the vasculature where the anatomical conditions are appropriate for the design.

[0024] The medical device may include one or more layers of occlusive material, wherein each layer may be comprised of any material that is configured to substantially preclude or occlude the flow of blood so as to facilitate thrombosis. As used herein, substantially preclude or occlude flow shall mean, functionally, that blood flow may occur for a short time, but that the body's clotting mechanism or protein or other body deposits on the occlusive material results in occlusion or flow stoppage after this initial time period.

[0025] Some embodiments of the present disclosure may be formed by a plurality of wire strands having a predetermined relative orientation with respect to one another. However, it is understood that according to additional embodiments of the present disclosure, that the medical device could be etched or laser cut from a tube, or the device could comprise an occlusion material coupled to a scaffolding structure or a plurality of slices of a tubular member coupled together.

[0026] The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the disclosure are shown. Indeed, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0027] In at least some conventional or known medical devices used for the occlusion of abnormalities, such as a medical device 50 shown in FIG. 1, medical device 50 includes a proximal end 52 and a distal end 54, with a disc 56 at proximal end 52 and a lobe 58 at distal end 54. The lobe 58 has a proximal edge 60 (also referred to as a proximal face), a distal edge 62 (also referred to as a distal face), and a middle or central portion 64 that define a cavity 66. The medical device 50 also includes stabilizing wires 68 secured to a radially outer or circumferential surface of middle portion 64. The stabilizing wires 68 terminate in a hook 70 at free ends thereof, and thereby facilitate retention of the medical device 50 at a target site and preventing the medical device 50 from becoming dislodged from the target site after deployment.

[0028] In this known medical device 50, proximal edge 60 and distal edge 62 adjoin middle portion 64 at a first relatively blunt or sharp (i.e., non-rounded) transition 72 and a second blunt transition 74, respectively. First blunt transition 72 connects proximal edge 60 to middle portion 64 by an approximately 90 degree angle. Likewise, second blunt transition 74 connects distal edge 62 to middle portion 64 by an approximately 90 degree angle. First blunt transition 72 and second blunt transition 74 partially define a generally rectangular cross section to lobe 58, leading to relatively blunt circumferential edges of the device and relatively high radial force applied to the surrounding tissue.

[0029] Turning now to FIGS. 2A-2C, medical device 50 before and after undergoing radial compression is depicted. Before radial compression (FIG. 2A) is applied to lobe 58, the outer surface of middle portion 64 is linear or extends generally perpendicular to proximal and distal faces 60, 62. Each hook 70 of a corresponding stabilizing wire 68 is at a first angle 76 with respect to a generally longitudinal direction 77. When radial compression is applied to lobe 58 (FIGS. 2B and 2C), proximal and distal faces 60, 62 flex and bow outwardly (e.g., axially outward), and middle portion 64 of lobe 58 flexes and bows inwardly, in response to the applied force. The approximately 90 degree angle of first blunt transition 72 and second blunt transition 74 force the outer surface of middle portion 64 to transition from linear to concave when proximal and distal faces 60, 62 bow outwardly. The concave shape adopted by lobe 58 also shifts the position of stabilizing wires 68, such that stabilizing wires 68 at least partially contract and hooks 70 transition from first angle 76 to a second, greater angle 78. At second angle 78, hooks 70 are oriented more directly towards the adjacent tissue, than when hooks 70 are at first angle 76. This shift in orientation of stabilizing wires 68, and therefore hooks 70, can lead to an increase in interactions between hooks 70 and the adjacent tissue at the target site within the patient's body. The increased interaction with tissue can lead to adverse side effects such as late pericardial effusion.

[0030] The medical devices of the present disclosure, which include a rounded lobe, can lead to a more uniform radial compression, reduction in radial force applied to surrounding tissue, and reduction in variability of the hook angle of the stabilizing wires, minimizing potential disadvantages of known medical devices.

[0031] Turning now to FIG. 3, a schematic diagram of a delivery system 100 is shown. Delivery system 100 includes a delivery device 102 including a catheter 104 and a coupling member 106 configured to couple a distal end of a delivery cable 108 to a medical device 110 for facilitating the deployment of medical device 110 at a target site. Medical device 110 is deployed to treat the target site, and, in the example embodiment, is an occlusion device (occluder).

[0032] FIG. 4 illustrates an exemplary embodiment of medical device 110. Medical device 110 includes a proximal end 112 and a distal end 114. Proximal end 112 includes a disc 116, and distal end 114 includes a lobe 118, wherein disc 116 and lobe 118 are connected by a connecting member 120. Lobe 118 includes a proximal portion 122 defining a proximal surface 124 of lobe 118, a distal portion 126 defining a distal surface 128 of lobe 118, and a middle or central portion 130 connecting and extending between proximal portion 122 and distal portion 126. Central portion 130 has a circumferential or radially outer surface 131. Proximal surface 124 is connected to or adjoins middle portion 130 at a first transition T1, and distal surface 128 is connected to or adjoins middle portion 130 at a second transition T2. First transition T1 and second transition T2 each independently have a radius of curvature of 0.001 inches to 0.150 inches, more particularly 0.025 inches to 0.150 inches, even more particularly 0.075 inches to 0.125 inches. The radius of curvature of first transition T1 is the same as the radius of curvature of second transition T2. Alternatively, first transition T1 and second transition T2 have different radii of curvature. In one alternative embodiment, only one of first transition T1 and second transition T2 has a defined radius of curvature, and the other is a relatively blunt transition (e.g., approximately) 90.

[0033] Lobe further 118 includes a plurality of stabilizing wires 132 coupled to lobe 118 at radially outer surface 131 (also referred to as circumferential surface) of middle portion 130. Stabilizing wires 132 each include a hook 134 at a terminal end therefore. Hooks 134 extend radially outward from middle portion 130 of lobe 118.

[0034] Some embodiments of medical device 110 of the present disclosure may be formed from a braided fabric or mesh material including a plurality of wire strands having a predetermined relative orientation with respect to one another. However, it is understood that according to additional embodiments of the present disclosure, medical device 110 could be etched or laser cut from a tube, or the device could comprise an occlusion material coupled to a scaffolding structure or frame.

[0035] In one embodiment, medical device 110 is formed from a shape-memory material including a metal fabric. The metal fabric is deformed to generally conform to a surface of a mandrel. While on the surface of the mandrel, the metal fabric is treated under heated conditions to allow for the heat-setting of the metal fabric. The heat-setting of the metal fabric ensures that the metal fabric will retain the substantial shape of the mandrel once it is removed from the surface of the mandrel. In the exemplary embodiment, the mandrel utilized for the heat-setting treatment defines the radii of curvature adopted by the metal fabric for the edges of lobe 118 of medical device 110, specifically first transition T1 and second transition T2.

[0036] The radius of curvature selected and defined for each of first transition T1 and second transition T2 rounds or softens the circumferential edges of medical device 110. This rounding or softening of the circumferential edge leads to a reduction in the radial force applied to the surrounding tissue. Therefore, medical device 110 is more conformable to the anatomy of the target site in which it is deployed, specifically an LAA.

[0037] Disc 116 of medical device 110 is configured to abut the adjacent wall surrounding the opening of the vascular defect to prevent movement of medical device 110 and to assist in sealing of the abnormality in which medical device 110 is deployed. Different sizes and shapes of the disc are contemplated. In one embodiment, the disc portion may be larger in diameter than the vascular abnormality to be occluded to be capable of overlying the opening of the abnormality.

[0038] Lobe 118 of medical device 110 is formed to have a suitable size to engage with the lumen of the abnormality that is to be occluded. Medical device 110 may then be held at the target site by radial engagement between lobe 118 and the lumen of the abnormality. Hooks 134 of stabilizing wires 132 also engage with the surrounding tissue and improve retention of medical device 110 at the target site.

[0039] In addition to the rounding or softening of the circumferential edges of lobe 118, the rounding of the first and second transitions facilitates more uniform radial compression of lobe 118 when deployed at the target site. FIGS. 5A and 5B illustrate medical device 110 in accordance with the present disclosure undergoing radial compression. Before radial compression is applied to medical device 110 (FIG. 5A), radially outer surface 131 of middle portion 130 is generally linear between first transition T1 and second transition T2. In addition, hooks 134 are oriented at a first angle A1 with respect to a longitudinal direction 140. When radial compression is applied to lobe 118 (FIGS. 5B and 6), proximal surface 124 and distal surface 128 still bow outwardly (e.g., axially or longitudinally outward) in response to the applied force. In response, middle portion 130 may flex but resists bowing radially inward. Specifically, rounded first and second transitions T1, T2 enable proximal surface 124 and distal surface 128 to flex outwardly, without middle portion 130 flexing or compressing in a concave manner, or without middle portion 130 bowing inwardly. Therefore, stabilizing wires 132 are not substantially shifted or contracted, and hooks 134 maintain first angle A1. It is contemplated that hooks 134 may undergo a slight shift, but this shift is minimal and greatly reduced compared to the shift of the hooks in known medical devices, as described above.

[0040] One particular shape memory material that may be used to form medical device 110 (and, particularly, lobe 118) as described herein is Nitinol. Nitinol alloys are highly elastic and are said to be superelastic, or pseudoelastic. This elasticity may allow medical device 110 to be resilient and return to a preset, expanded configuration for deployment following passage in a distorted form through delivery catheter 104. Further examples of materials and manufacturing methods for medical devices with shape memory properties are provided in U.S. Publication No. 2007/0265656 titled Multi-layer Braided Structures for Occluding Vascular Defects and filed on Jun. 21, 2007, which is incorporated by reference herein in its entirety.

[0041] It is also understood that medical device 110 may be formed from various materials other than Nitinol that have elastic properties, such as stainless steel, trade named alloys such as Elgiloy, or Hastalloy, Phynox, MP35N, CoCrMo alloys, metal, polymers, or a mixture of metal(s) and polymer(s). Suitable polymers may include PET (Dacron), polyester, polypropylene, polyethylene, HDPE, Pebax, nylon, polyurethane, silicone, PTFE, polyolefins and ePTFE. Additionally, it is contemplated that the medical device may comprise any material that has the desired elastic properties to ensure that the device may be deployed, function as an occluder as disclosed within this application.

[0042] Turning now to FIG. 7, a flow diagram of an exemplary method 700 of using medical device 110 to occlude an LAA in a patient is depicted. In the exemplary embodiment, method 700 includes providing 702 a medical device. As described herein, the medical device includes a proximal and a distal end, wherein the proximal end comprises a disc and the distal end comprises a lobe, wherein the lobe comprises a proximal portion defining a proximal surface of the lobe, a distal portion defining a distal surface of the lobe, and a middle portion connecting and extending between the proximal portion and the distal portion, wherein a first transition between the proximal portion and the middle portion is curved and a second transition between the middle portion and the distal portion is curved, wherein the lobe has an expanded configuration when deployed at the target site and a reduced configuration for delivery to the target site, wherein the disc and lobe are connected by a connecting member, and a plurality of stabilizing wires coupled to the lobe at a radially outer surface of the middle portion, each stabilizing wire comprising a hook portion extending radially outward from the at least one lobe.

[0043] Method 700 also includes advancing 704 the medical device to the LAA using a delivery system including a catheter and a delivery cable, positioning 706 the medical device relative to the LAA to occlude blood flow to and from the LAA, and de-coupling 708 the medical device from the delivery cable to deploy the medical device.

[0044] Method 700 may include additional, alternative, and/or fewer steps, including those described herein. For example, in some embodiments, positioning 706 the medical device relative to the LAA includes placing the lobe of the medical device within the body of the LAA and the disc outside of the LAA abutted to the adjacent wall surrounding the opening of the LAA to prevent movement of the medical device towards the body of the LAA and to assist in scaling of the abnormality.

[0045] Turning now to FIG. 8, a flow diagram of an exemplary method 800 of fabricating a medical device (e.g., medical device 110) is depicted. As described herein, the medical device includes a proximal and a distal end, wherein the proximal end comprises a disc and the distal end comprises a lobe, wherein the lobe comprises a proximal portion defining a proximal surface of the lobe, a distal portion defining a distal surface of the lobe, and a middle portion connecting and extending between the proximal portion and the distal portion, wherein a first transition between the proximal portion and the middle portion is curved and a second transition between the middle portion and the distal portion is curved, wherein the lobe has an expanded configuration when deployed at the target site and a reduced configuration for delivery to the target site, wherein the disc and lobe are connected by a connecting member, and a plurality of stabilizing wires coupled to the lobe at a radially outer surface of the middle portion, each stabilizing wire comprising a hook portion extending radially outward from the at least one lobe. In the exemplary embodiment, method 800 includes providing 802 a shape-memory material.

[0046] Method 800 also includes positioning 804 the shape memory material on a mandrel having a desired shape, size, and radius of curvature for the first transition and a radius of curvature for the second transition, heat setting 806 the shape-memory material to define the expanded preset configuration having the radius of curvature for the first transition and the radius of curvature for the second transition, removing 808 the shape-memory material from the mandrel to obtain the medical device in the expanded preset configuration.

[0047] Method 800 may include additional, alternative, and/or fewer steps, including those described herein. For example, in some embodiments, removing 808 the shape-memory material from the mandrel includes cooling the shape-memory material to room temperature.

[0048] While embodiments of the present disclosure have been described, it should be understood that various changes, adaptations and modifications may be made therein without departing from the spirit of the disclosure and the scope of the appended claims. Further, all directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of the disclosure. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the disclosure as defined in the appended claims.

[0049] Many modifications and other embodiments of the disclosure set forth herein will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments described and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0050] Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.