Multi-wire embolic protection filtering device

[0001] The present invention pertains to filtering devices. More particularly, the present invention pertains to embolic protection filtering devices that are compatible with a number of different shafts.

[0002] Heart and vascular disease are major problems in the United States and throughout the world. Conditions such as atherosclerosis result in blood vessels becoming blocked or narrowed. This blockage can result in lack of oxygenation of the heart, which has significant consequences since the heart muscle must be well oxygenated in order to maintain its blood pumping action.

[0003] Occluded, stenotic, or narrowed blood vessels may be treated with a number of relatively non-invasive medical procedures including percutaneous transluminal angioplasty (PTA), percutaneous transluminal coronary angioplasty (PTCA), and atherectomy. Angioplasty techniques typically involve the use of a balloon catheter. The balloon catheter is advanced over a guidewire such that the balloon is positioned adjacent a stenotic lesion. The balloon is then inflated and the restriction of the vessel is opened. During an atherectomy procedure, the stenotic lesion may be mechanically cut away from the blood vessel wall using an atherectomy catheter.

[0004] During angioplasty and atherectomy procedures, embolic debris can be separated from the wall of the blood vessel. If this debris enters the circulatory system, it could block other vascular regions including the neural and pulmonary vasculature. During angioplasty procedures, stenotic debris may also break loose due to manipulation of the blood vessel. Because of this debris, a number of devices, termed embolic protection devices, have been developed to filter out this debris.

[0005] The invention provides design, material, manufacturing method, and use alternatives for intravascular filtering devices. In at least some embodiments, these filtering devices include an embolic protection filter that is adapted to be releasably attachable to a shaft. These and other desirable features are described in greater detail below.

[0006] FIG. 1 is perspective view of an example filtering device;

[0007] FIG. 2 is a perspective view of an example filtering device with an inflated coupling member;

[0008] FIG. 3 is a cross-section view taken through line 3-3;

[0009] FIG. 3A is an alternative cross-section view taken through line 3-3;

[0010] FIG. 4 is a perspective view of an example filtering device with an inflation tube attached to a coupling member;

[0011] FIG. 5 is a perspective view of another example filtering device including an inflation tube;

[0012] FIG. 6 is a perspective view of another example filtering device;

[0013] FIG. 7 is a perspective view of an example filtering device in a collapsed configuration;

[0014] FIG. 8 is a side view of an example arrangement for a filtering device;

[0015] FIG. 9 is a side view of another example arrangement for a filtering device;

[0016] FIG. 10 is a perspective view of another example filtering device;

[0017] FIG. 11 is a perspective view of another example filtering device;

[0018] FIG. 12 is a perspective view of another example filtering device;

[0019] FIG. 13 is a perspective view of another example filtering device; and

[0020] FIG. 14 is a perspective view of the filtering device of FIG. 13 where the expansion member is inflated.

[0021] The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings illustrate example embodiments of the claimed invention.

[0022] FIG. 1 is a side view of an example filtering device 10 including a filter 12 having a distal coupling member 14. Coupling member 14 may be adapted and configured for releasably attaching filter 12 to a shaft 16. This structural feature may provide filtering device 10 with a number of desirable features. For example, coupling member 14 may allow filter 12 to be attached to essentially any shaft such as virtually any of the various commercially available guidewires. This and other desirable features are described in more detail below.

[0023] In general, filter 12 may be adapted to operate between a first generally collapsed configuration and a second generally expanded configuration for collecting debris in a body lumen. In some embodiments, filter 12 can be delivered to an appropriate intravascular location, for example downstream of an intravascular lesion, using an appropriate filter delivery device. Similarly, filter 12 can be removed from the vasculature at the desired time by an appropriate filter retrieval device.

[0024] Filter 12 may include a filter frame 18 and a filter membrane or fabric 20 coupled to filter frame 18. Frame 18 may take the form of any one of a number of appropriate shapes and configurations. For example, frame 18 may comprise a generally circular filter mouth or loop, which may defines the primary opening for blood to travel into and be filtered by filter 12. However, essentially any appropriate shape or configuration may be utilized without departing from the spirit of the invention.

[0025] Frame 18 may be comprised of any appropriate material. For example, frame 18 may be comprised of a self-expanding shape-memory material such as nickel-titanium alloy (to bias filter 12 to be in the second expanded configuration). Alternatively, frame 18 may be comprised of essentially any appropriate metal, metal-alloy, polymer, combinations thereof, and the like including any of the materials described herein. In some embodiments, frame 18 or portions thereof may be doped with, plated with, 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 the user of device 10 in determining its location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, plastic material loaded with a radiopaque filler, and the like. For example, a radiopaque wire disposed about a portion of frame 18.

[0026] Filter membrane 20 may be comprised of any appropriate material such as a polymer and may be drilled (for example, formed by known laser techniques) or otherwise include at least one opening 22. Holes or openings 22 can be sized to allow blood flow therethrough but restrict flow of debris or emboli floating in the body lumen or cavity.

[0027] The embodiment shown in FIG. 1 illustrates shaft 16 as being a guidewire. However, shaft 16 is not intended to be limited to being only a guidewire. It can be appreciated that shaft 16 may comprise number of different structures including a catheter (e.g., therapeutic, diagnostic, or guide catheter), endoscopic device, laproscopic device, an embolic protection device, or any other suitable device. In some embodiments, shaft 16 may comprise a tubular filter cartridge. According to this embodiment, filtering device 10 can be configured to be slidable over a guidewire or other suitable medical device.

[0028] Coupling member 14 may comprise a number of different materials including polymers. Some examples of suitable polymers may include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyurethane, polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example a polyether-ester elastomer such as ARNITEL available from DSM Engineering Plastics), polyester (for example a polyester elastomer 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), silicones, polyethylene, Marlex high-density polyethylene, linear low density polyethylene (for example REXELL), polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA), electroactive polymers (i.e., polymers that respond to electrical stimulation), ferromagnetic polymers (i.e., polymers that respond to energy such as radiofrequency energy), other suitable materials, or mixtures, combinations, or copolymers thereof. In some embodiments coupling member 14 can include a liquid crystal polymer (LCP) blended with other polymers to enhance torqueability. Coupling member 14 may also be doped with or otherwise include radiopaque materials including those described herein.

[0029] In some embodiments, coupling member 14 may be comprised other materials such as metals, metal alloys, metal-polymer composites, and the like. For example, coupling member 14 may comprise a shape memory allow such as nickel-titanium alloy such as nitinol, nickel-chromium alloy, nickel-chromium-iron alloy, and the like. These may allow for coupling member 14, for example, to more securely attach to shaft 16.

[0030] In some embodiments, a coating, for example a lubricious, a hydrophilic, a protective, or other type of coating may be applied over portions or all of coupling member 14, or other portions of device 10. Hydrophobic coatings such as fluoropolymers provide a dry lubricity which improves device handling and exchanges. Lubricious coatings improve steerability and improve lesion crossing capability. Suitable lubricious polymers are well known in the art and may include silicone and the like, hydrophilic polymers such as polyarylene oxides, polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics, algins, saccharides, caprolactones, and the like, and mixtures and combinations thereof. Hydrophilic polymers may be blended among themselves or with formulated amounts of water insoluble compounds (including some polymers) to yield coatings with suitable lubricity, bonding, and solubility. Some other examples of such coatings and materials and methods used to create such coatings can be found in U.S. Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein by reference.

[0031] Coupling member 14 may comprise a number of different shapes. For example, coupling member 14 may be generally cylindrical in shape as shown in FIG. 1. Alternatively, coupling member 14 may comprise other shapes including those similar to an o-ring, tire, donut, oval, and the like. It can be appreciated that coupling member 14 may be essentially any appropriate shape. Additionally, the size and/or length of coupling member 14 may vary. For example, coupling member may be about 1 mm to about 2 mm in length or longer.

[0032] In at least some embodiments, coupling member 14 may comprise an elastic material that would frictionally attach filter 12 to shaft 16. Accordingly, a user can exert sufficient force to slide filter 12 over shaft 16. Upon sliding filter 12 to the desired location along shaft 16, the position of the filter 12 can then be substantially maintained by the frictional fit between filter 12 and shaft 16. Alternatively, coupling member 14 may comprise a swellable material that swells when exposed to an appropriate stimuli. In still other embodiments, coupling member 14 may include one or more chemicals that, when combined or exposed to the appropriate stimui, react to cause expansion of coupling member 14 or otherwise change the configuration thereof so as to secure coupling member 14 to shaft 16.

[0033] Coupling member 14, or any of the other structural elements described herein, may include a drug or other substance that may elute or diffuse therefrom. For example, coupling member 14 may include an anti-coagulation drug such as heparin that may help discourage coagulation of blood adjacent coupling member 14. Other diagnostic and therapeutic substances may be included without departing from the spirit of the invention.

[0034] In addition or as an alterative to the above embodiments, coupling member 14 may be inflatable. According to this embodiment, coupling member 14 can shift between at least a first and second configuration. The first configuration may be a generally deflated configuration, wherein filter 12 is slidable along shaft 16. The second configuration may be a generally inflated configuration, wherein the position of filter 12 is substantially fixed relative to shaft 16 as shown in FIG. 2. In use, for example, a user may advance filter 12 along shaft 16 to the desired position and then inflate coupling member 16 to secure filter 12 to shaft 16.

[0035] FIG. 3 illustrates that, when inflated, coupling member 14 may exert a force on shaft 16 to secure filter 12 thereto. According to this embodiment, the inside surface of coupling member 14 may generally conform to the shape of shaft 16. Some alternative coupling members 114 may include one or more teeth 123 and/or dimples 125 on its inside surface as shown in FIG. 3A that may help strengthen the bond between coupling member 114 and shaft 16. According to this embodiment, when coupling member 114 is inflated, teeth 123 may facilitate the gripping force exerted by coupling member 114 on shaft 16. Teeth 123 and dimples 125 can vary in number, shape, arrangement, longitudinal length, etc.

[0036] Coupling member 14 may be inflated in a number of different ways. For example, FIG. 4 illustrates that coupling member 14 may include an inflation port 24 that is adapted to receive an inflation tube or member 26. Inflation of coupling member 14, thus, may include releasably coupling inflation tube 26 to inflation port 24, infusing inflation media into coupling member 14 to inflate it, and then removing inflation tube 26 from port 24. According to this embodiment, port 24 may include a valve or other suitable means to hermetically seal coupling member 14.

[0037] A number of alternative arrangements and/or devices may be utilized to inflate coupling member 14. For example, other medical devices such as catheters or guidewires that have inflation lumens may be disposed adjacent coupling member 14 and used to inflate it. According to this embodiment, a medical device can be advanced along shaft 16 to a position adjacent coupling member 14, configured so that the inflation lumen of the medical device is in fluid communication with coupling member 14, and then inflation media can be passed from the inflation lumen into coupling member 14.

[0038] An alternative filtering device 110 is depicted in FIG. 5. Device 110 is essentially the same in form and function as device 10, except that inflation tube 126 is adapted for being attached to coupling member 14 and extending proximally therefrom, for example adjacent or along shaft 16. This arrangement may allow filter 12 to be slid along a medical device already placed in a blood vessel. Once properly positioned, coupling member 14 can then be inflated to secure filter 12 to shaft.

[0039] Another example filtering device 210 is shown in FIG. 6. Device 210 is essentially the same in form and function as any of the devices described herein except that filter 212 includes an expansion member 228. In at least some embodiments, expansion member 228 may comprise an inflatable cylinder that may, for example, be inflated to open or expand filter 212. According to this embodiment, one or more inflation tubes 230a/b may be coupled to expansion member 228 and extend proximally therefrom. Inflation tubes 230a/b may be attached to a suitable inflation device so that inflation medium may be infused through tubes 230a/b into expansion member 228 to inflate it and expand filter 212.

[0040] Expansion member 228 may also provide filtering device 210 (and/or filter 212) with a number of additional desirable features. For example, expansion member 228 may improve vessel wall apposition. This is because at least some embodiments of expansion member 228 are sufficiently compliant to conform to even the most irregularly shaped vessel wall. Thus, expansion member 228 may allow filter 212 to substantially seal essentially the entire circumference of the vessel wall.

[0041] Additionally, expansion member 228 may have a length that allows it to help secure filter 212 more securely within a blood vessel. This structural feature may allow filter 212 to maintain it position within the blood vessel even when subjected to potentially displacing forces associated with moving blood and/or debris. In some embodiments, the length may be on the order of, for example, about 4 mm to about 5 mm or more.

[0042] The materials, shape, and other features of expansion member 228 may be essentially the same as what is described above. For example, expansion member 228 may comprise a polymer that is generally cylindrical in shape. However, the shapes, materials, etc. can vary to include any appropriate configuration. In at least some embodiments, expansion member 228 (like any of the structural elements disclosed herein) may include a radiopaque material. The radiopaque materials may be dispersed throughout expansion member 228 or may be arranged in a specific, known banding pattern. This later feature, combined with a desirable length, may allow expansion member 228 to be used for both visualization of filter 212 and for measurement within a blood vessel.

[0043] In use, filtering device 210 may be placed within a blood vessel at an appropriate target region. The steps involved in placing and/or delivering device 210 may include a number of steps. For example, filter 212 may be advanced along shaft 16 to the desired location and secured thereto in an appropriate manner, for example by inflating coupling member 214. Advancing filter 212 may occur outside the body (where inflation of coupling member 214 may include releasably attaching an inflation tube as described in relation to FIG. 4 above) or within the body (where inflation of coupling member 214 may include passing inflation media through an inflation tube in a manner similar to what is described in relation to FIG. 5).

[0044] Filter 212 (in a collapsed configuration as shown in FIG. 7) can be advanced through the blood vessel in a suitable manner such as with the use of an appropriate filter delivery device. Once properly positioned, expansion member 228 can be inflated to expand and open filter 212. Filter 212 can then be used to capture embolic debris.

[0045] A diagnostic or treatment device 232 such as an angioplasty or atherectomy catheter can be advanced over shaft 16 to a position adjacent an intravascular lesion and upstream of filter 212 as shown in FIG. 8. Debris generated by the use of treatment device 232 can be captured by filter 212. Prior to or during the use of treatment device 232, expansion member 228 may be deflated. Even when deflated, it is believed that filter 212 will maintain its expanded or open configuration due to flow of blood through filter 212.

[0046] The arrangement of inflation tubes 230a/b in relation to treatment device 232 may vary. For example, inflation tubes 230a/b may be positioned so that tubes 230a/b run substantially parallel to the vessel wall as shown in FIG. 8. This arrangement may be desirable, for example, by allowing treatment device 232 to have a smaller profile by not requiring a lumen 234 that is large enough to accommodate tubes 230a/b. According to this embodiment, treatment device 232 may be advanced over shaft 16 and under tubes 230a/b.

[0047] Alternatively, tubes 230a/b may be arranged to pass through lumen 234 of treatment device 232 as shown in FIG. 9. This arrangement may be desirable for a number of reasons. For example, if the intervention includes the placement of or the use of a stent, it may be desirable to keep tubes 230a/b from contacting and possibly displacing the stent. Additionally, passing tubes 230a/b through lumen 234 or through an analogous lumen of a suitable retrieval device may also aid in retrieval of filter 212. For example, as the retrieval device is advanced over shaft 16 and tubes 230a/b toward filter 212, tubes 230a/b may begin to exert an inward force on filter 212 (adjacent expansion member 228), which can aid in placing filter 212 within the retrieval device so that filter 212 can be removed from the vasculature.

[0048] Another example filtering device 310 is shown in FIG. 10. Device 310 is similar to other devices described herein and includes filter 312 having coupling member 314, inflation tube 326 coupled to coupling member 314, expansion member 328, and inflation tubes 330a/b coupled to expansion member 328. This figure shows an example embodiment that essentially combines the structural features illustrated in FIGS. 5 and 6, and that may be used in a manner that is analogous to what is described in relation to FIGS. 5-9.

[0049] FIG. 11 is a cross-sectional view of another example filtering device 410. Device 410 is similar to other devices described herein and includes filter 412 having one or more longitudinal ribs 436 that may be disposed between expansion member 428 and coupling member 414. The precise location of ribs 436, however, may vary. Moreover, ribs 436 may be included with or without expansion member 428 and/or coupling member 414.

[0050] Ribs 436 may be inflatable so that upon inflation they can expand filter 412. Inflation of ribs 436 may occur in any one of a number of different ways. For example, an inflation tube 438 may be coupled to ribs 436 so that inflation media can be infused into ribs 436. In some embodiments, inflation tube 438 may be used to inflate any combination of the inflatable structural elements that are present (e.g., coupling member 414, expansion member 428, and ribs 436). Alternatively, any of the inflatable structures may include inflation tubes or other inflation means such as any of those described herein.

[0051] FIG. 12 is a perspective view of another example filtering device 510. Device 510 is essentially the same in form and function as any of the devices described herein, except that filter 512 may include one or more strut fibers 540 extending between filter 512 and a slip ring 542 disposed about shaft 16. A proximal fiber 544 may be coupled to slip ring 542 and extend proximally therefrom. According to this embodiment, proximally pulling on fiber 544 may shift slip ring 542 proximally and, consequently, at least partially collapse or close filter 512.

[0052] FIG. 12 also depicts device 510 as including expansion member 528 and coupling member 514. Inflation tubes or other inflation means for these structures may include any of those described herein and, for simplicity, are not included in FIG. 11. It can be appreciated that strut fibers 540, slip ring 542, and proximal fiber 554 may be included in any of the embodiments of filtering devices described herein.

[0053] FIG. 13 shows another example filtering device 610 that is similar to other devices described herein. Device 610 may include an alternative example coupling member 614 that includes one or more gripping arms 646 that can pivot about a pivot point 648 so as to secure filter 612 to shaft 16. According to this embodiment, as expansion member 628 is inflated and expands, arms 646 pivot about pivot point 648 and secure filter 612 to shaft 16 as shown in FIG. 14.

[0054] 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 invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed.