Abstract:
The disclosure relates to an embolic filter deployment system and a method for deploying an embolic filter from the deployment system wherein the filter element and a containment element for the filter element are formed from a single piece of material.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates generally to an embolic filter deployment system and a method for deploying an embolic filter from the deployment system. 
       BACKGROUND 
       [0002]    Human blood vessels often become occluded or blocked by plaque, thrombi, other deposits, or material that reduce the blood carrying capacity of the vessel. Should the blockage occur at a critical place in the circulatory system, serious and permanent injury, and even death, can occur. To prevent this, some form of medical intervention is usually performed when significant occlusion is detected. 
         [0003]    Several procedures are now used to open these stenosed or occluded blood vessels in a patient caused by the deposit of plaque or other material on the walls of the blood vessels. Angioplasty, for example, is a widely known procedure wherein an inflatable balloon is introduced into the occluded region. The balloon is inflated, dilating the occlusion, and thereby increasing the intraluminal diameter. 
         [0004]    Another procedure is atherectomy. During atherectomy, a catheter is inserted into a narrowed artery to remove the matter occluding or narrowing the artery, i.e., fatty material. The catheter includes a rotating blade or cutter disposed in the tip thereof Also located at the tip are an aperture and a balloon disposed on the opposite side of the catheter tip from the aperture. As the tip is placed in close proximity to the fatty material, the balloon is inflated to force the aperture into contact with the fatty material. When the blade is rotated, portions of the fatty material are shaved off and retained within the interior lumen of the catheter. This process is repeated until a sufficient amount of fatty material is removed and substantially normal blood flow is resumed. 
         [0005]    In another procedure, stenosis within arteries and other blood vessels is treated by permanently or temporarily introducing a stent into the stenosed region to open the lumen of the vessel. The stent typically includes a substantially cylindrical tube or mesh sleeve made from such materials as stainless steel or nitinol. The design of the material permits the diameter of the stent to be radially expanded, while still providing sufficient rigidity such that the stent maintains its shape once it has been enlarged to a desired size. 
         [0006]    Such percutaneous interventional procedures, i.e., angioplasty, atherectomy, and stenting, can dislodge material from the vessel walls. This dislodged material can enter the bloodstream. Some existing devices and technology use a filter for capturing the dislodged material from the bloodstream. 
       SUMMARY 
       [0007]    The present disclosure pertains to an embolic filter deployment apparatus which can be configured to be used in connection with an intravascular device. The apparatus can include a guide wire, a filter element associated with the guide wire, a containment element, and an actuation element, movable between a first position and a second position to release the filter from the containment element. The filter element and the containment element can be regions of a single sheet substantially formed from a single piece of material, or multiple pieces bound together to form a single sheet. 
         [0008]    Additionally, an embolic filter can be deployed from a containment element, wherein the filter and containment element are formed from a single piece of material, or multiple pieces bound to form a single sheet. The method includes providing a structure or structures for joining the various parts of the containment element and an actuation element, movable between a first position and a second position such that when the actuation element is in the first position, the joining structures or elements hold the containment element in position about the filter and in the second position, the actuation element allows the joining structures or elements release the containment element thereby deploying the filter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0009]      FIG. 1A  illustrates an intermediate stage of the assembly of a filter assembly and 
           [0010]    FIG,  1 B illustrates the filter assembly as it is ready for delivery to the vessel to be protected. 
           [0011]      FIG. 2  illustrates a combined filter sheet. 
           [0012]      FIG. 3A  illustrates another combined filter sheet.  FIGS. 3B and 3C  illustrate details of actuation element and the joining element of the sheet of  FIG. 3A . 
           [0013]      FIG. 4A  illustrates another combined filter sheet including joining elements shown as mating fasteners.  FIG. 4B  is a detail of the mating fasteners in the engaged configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The drawings, which are not necessarily to scale, are not intended to limit the scope of the claimed invention. The detailed description and drawings illustrate example embodiments of the claimed invention. 
         [0015]    All numbers are herein assumed to be modified by the term “about.” The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
         [0016]    As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include the 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. 
         [0017]      FIGS. 1A and 1B  illustrate a filter assembly  10  disposed on a guide wire  12  Filter assembly  10  includes a filter frame  14  having a plurality of legs  16 . Filter assembly  10  also includes the filter element  18  including a filter fabric or mesh having a plurality of small apertures. Filter element  18  can have a conical shape wherein a major opening is defined at the proximal end which can be supported by legs  16 . The opposite end of filter element  18  can be attached to guide wire  18  at coupling  20 . Filter element  18  can be fixably attached to guide wire  12  by adhesive, soddering, welding or other technique. Alternatively, coupling  20  can include a bushing such that filter element  18  can be slidably and or rotatably attached guide wire  12 . Likewise, legs  16  of filter frame  14  can be attached to guide wire  12  by a coupling  22  by adhesive, soddering, welding or other technique. Alternatively, coupling  22  can be made to bushing to allow legs  16  and filter assembly  10  to rotate or slide on wire  12 . 
         [0018]    As shown in  FIGS. 1A and 1B , and in more detail in  FIG. 2 , filter assembly  10  includes a combination filter sheet  24 , having a filter element portion  26  and a containment element portion  28 . In  FIG. 1A , containment element portion  28  has been formed into a generally conically shaped filter element  18 . Containment element portion  28  is shown in a pre-containment or pre-assembled position and includes an aperature  30  through which a leg  16  extends, and a plurality of joining slits  32 . To complete the assembly, filter frame  14  and filter element  18  are compressed. Then containment element portion  28  is folded towards filter element  18 , wrapped around filter element  18  and held in position by joining opposite sides of containment element portion  28  using joining slits  32 . 
         [0019]    As shown in  FIG. 1B , containment element portion  28  has been folded over filter element portion  26  and joined at slits  32  by an actuation element  34  inserted through the slits on both sides of containment element  28 . Actuation element  34  can be formed from a pin or cord inserted through slits  32  and include a cord  36  which extends approximately, to the proximal end of filter assembly  10 , to allow a user to withdraw actuation filter  34  from slits  32 . This will allow the sides of containment element  28  to separate. Filter element  18  can then expand aided by legs  16  which can be formed from elastic material such as nickel titanium alloy or nitinol. Once filter element  18  is expanded across a body lumen, such as a blood vessel, the major opening can, for example, receive a flow of blood including emboli to be captured by filter element  18  while blood passes through the small aperatures in filter element  18 . 
         [0020]      FIG. 2  shows a combination of filter sheet  24  as cut from a single sheet, prior to placement on filter frame  14 . As shown in  FIG. 2 , filter element portion  26  is generally lying flat and includes opposite sides  27 . When disposed on filter frame  14  and guide wire  12 , filter element portion  26  is wrapped around guide wire  12  to form conically shaped filter element  18 . Sides  27  are joined together by adhesive, welding or other method. Filter element portion  26  and containment element portion  28  may be cut from a single piece of polymeric sheet material or mesh in a single step to form combination filter sheet  24 . As used herein, “single sheet” means only one sheet, however, the one sheet may be formed from one or more sheets bound together. Thus, combination filter sheet  24  can be cut from one sheet of material, inherently producing a combination filter sheet  24  in a “single sheet”. Alternatively, filter element portion  26  and containment element portion  28  may be formed from more than one sheet which are then bound together to form a “single sheet”. That is the more than one sheets are joined to become a “single” sheet which is a unitary combination of the more than one sheets. 
         [0021]    The material used to form the combined filter sheet  24  may be, for example, laser cut to shape in the same process that cuts holes through which blood cells, but not emboli and other debris, may pass. The same operation also may form apertures or other structures which serve as joining slits or elements that, alone or in combination with an actuating element hold the filter element portion of the unitary filter assembly and containment element portion in a folded or otherwise compact configuration when actuation element  34  is in a first position and which release containment element portion, and thus the filter element  18 , when actuation element  34  is in a second position. 
         [0022]    The sheet from which the combined filter sheet  24  is formed may be a continuous sheet, a pre-perforated sheet, or a woven mesh. It may be formed of any material which is sufficiently flexible and compatible with bodily fluids such as blood. Examples of suitable materials include polyurethane, polyolefin, polyester, and silicone polymers. Assembly of the combined filter sheet  24 , as well as other structures which make up the filter assembly  10 , may employ materials and methods such as adhesives, sewing, solvent welding, ultrasonic welding, crimping, and the like. 
         [0023]    In some embodiments, the entire sheet from which the filter and the combination filter sheet  24  is formed is perforated. In other embodiments, the fabrication process punches or drills holes through at least the portion of the sheet which will form the filter element  18  in order to provide fluid communication between the interior and exterior of the filter element  18 . In some embodiments, holes associated with the filter are formed at the time that combination filter sheet  24  is extracted from the sheet. In other embodiments, holes are provided in a separate step. Similarly, the fabrication of the combined filter sheet may include forming joining slits  32 , generally associated with containment element portion  28 , from portions of the original sheet as by perforation, or joining slits  32  may be constructed from different materials and/or in a separate operation. 
         [0024]      FIG. 3A  illustrates a combined filter sheet  124  comprising a filter element portion  124  and two containment elements  128  each of which include joining elements or slits  32 . The filter sheet  10  may be cut from a single sheet of appropriate polymer. Holes  129  may be laser cut or punched and should be sized to permit blood cells to pass through freely while retaining emboli and other debris. The generally conical filter assembly is formed by joining the filter sheet along lines  38  by any convenient method such as stitching, gluing, thermal welding and the like. Following attachment to a support structure, such as filter frame  14  of filter assembly  10 , the containment element portion  128  are then wrapped about the filter element and/or the associated support structure and joined by inserting actuation element  34  through slits  32  elements as shown in a first position in  FIG. 3B  and in perspective detail in  FIG. 3C . Following positioning the filter assembly in a desired position within a vessel, the actuation element  34  may be withdrawn to a second position to release the joining slits  32  of the containment element portions  24  thereby allowing the filter element  18  to deploy. 
         [0025]      FIG. 4A  is a view of an asymmetric combination filter sheet  224  having containment element portions  228  and filter element portion  226  with mating fastener joining elements  40 . The joining elements  40  may be attached in a separate operation or, in some embodiments may be thermoformed from a portion of the combination filter sheet  224 . In such embodiments, it may be useful to fold the edges of the sheet over to obtain more material from which to form mating structures  40 . The sheet  224  is joined along lines  238  as before and the resulting filter is attached to a support structure, for example, filter frame  14 . Following collapse of the support structure, the containment element portions  228  are wrapped about filter element  18  and/or the support structure and mating fasteners  40  are pressed together to engage the respective ribs  42  as shown in  FIG. 4B . Once the filter has been deployed by a guide wire or catheter, an actuation element  234  having a generally wedge-shaped configuration can be drawn between the two joining elements  40  to separate them in a zipper-like manner thus releasing the filter element. 
         [0026]    Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and principles of this disclosure, and it should be understood that this invention is not to be unduly limited to the illustrative disclosure set forth hereinabove. All publications and patents are herein incorporated by reference to the same extent as if each individual publication or patent was specifically and individually indicated to be incorporated by reference.