Abstract:
An embolic protection filtering device and method of making and using the same. The present invention comprises a filtering device including an elongate shaft and a filter that may be releasably attachable to the shaft. The filter may include a coupling member that may be used to secure the filter to the shaft.

Description:
[0001]     This application is a continuation of U.S. application Ser. No. 10/373,004, filed Feb. 24, 2003. 
     
    
     FIELD OF THE INVENTION  
       [0002]     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.  
       BACKGROUND  
       [0003]     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.  
         [0004]     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.  
         [0005]     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.  
       BRIEF SUMMARY  
       [0006]     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. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is perspective view of an example filtering device;  
         [0008]      FIG. 2  is a perspective view of an example filtering device with an inflated coupling member;  
         [0009]      FIG. 3  is a cross-section view taken through line  3 - 3 ;  
         [0010]      FIG. 3A  is an alternative cross-section view taken through line  3 - 3 ;  
         [0011]      FIG. 4  is a perspective view of an example filtering device with an inflation tube attached to a coupling member;  
         [0012]      FIG. 5  is a perspective view of another example filtering device including an inflation tube;  
         [0013]      FIG. 6  is a perspective view of another example filtering device;  
         [0014]      FIG. 7  is a perspective view of an example filtering device in a collapsed configuration;  
         [0015]      FIG. 8  is a side view of an example arrangement for a filtering device;  
         [0016]      FIG. 9  is a side view of another example arrangement for a filtering device;  
         [0017]      FIG. 10  is a perspective view of another example filtering device;  
         [0018]      FIG. 11  is a perspective view of another example filtering device;  
         [0019]      FIG. 12  is a perspective view of another example filtering device;  
         [0020]      FIG. 13  is a perspective view of another example filtering device; and  
         [0021]      FIG. 14  is a perspective view of the filtering device of  FIG. 13  where the expansion member is inflated. 
     
    
     DETAILED DESCRIPTION  
       [0022]     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.  
         [0023]      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.  
         [0024]     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.  
         [0025]     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.  
         [0026]     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 .  
         [0027]     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.  
         [0028]     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.  
         [0029]     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.  
         [0030]     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 .  
         [0031]     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.  
         [0032]     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.  
         [0033]     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 .  
         [0034]     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.  
         [0035]     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 .  
         [0036]      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.  
         [0037]     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 .  
         [0038]     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 .  
         [0039]     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.  
         [0040]     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  230   a/b  may be coupled to expansion member  228  and extend proximally therefrom. Inflation tubes  230   a/b  may be attached to a suitable inflation device so that inflation medium may be infused through tubes  230   a/b  into expansion member  228  to inflate it and expand filter  212 .  
         [0041]     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.  
         [0042]     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.  
         [0043]     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.  
         [0044]     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 ).  
         [0045]     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.  
         [0046]     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 .  
         [0047]     The arrangement of inflation tubes  230   a/b  in relation to treatment device  232  may vary. For example, inflation tubes  230   a/b  may be positioned so that tubes  230   a/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  230   a/b . According to this embodiment, treatment device  232  may be advanced over shaft  16  and under tubes  230   a/b.    
         [0048]     Alternatively, tubes  230   a/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  230   a/b  from contacting and possibly displacing the stent. Additionally, passing tubes  230   a/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  230   a/b  toward filter  212 , tubes  230   a/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.  
         [0049]     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  330   a/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 .  
         [0050]      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 .  
         [0051]     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.  
         [0052]      FIG. 12  is a perspective view of another example filtering device  510 . Device  5   10  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 .  
         [0053]      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, arc 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.  
         [0054]      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 .  
         [0055]     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&#39;s scope is, of course, defined in the language in which the appended claims are expressed.