Patent Publication Number: US-2016242893-A1

Title: Stent And Filter

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 62/120,814 filed Feb. 25, 2015 entitled Stent and Filter, which is hereby incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Many interventional procedures utilize a stent for various therapeutic purposes, such as to open a vessel blocked by thrombus, disease, or calcification. In many of these procedures a filter or embolic protection device is initially introduced to prevent particles from traveling through the patient&#39;s vascular system and causing complications, such as a stroke. A stent is advanced to a location proximal and upstream to the filter so that any dislodged material (e.g., thrombus) is captured by the filter and safely withdrawn from the patient. It should be noted that the filter and the stent must be delivered via separate devices and therefore the initial positioning of the filter otherwise lengthens and complicates the stent deliver procedure. 
     SUMMARY OF THE INVENTION 
     In one embodiment a stent with a filter is described. 
     In one embodiment a stent with a filter and a connecting structure is described. 
     In one embodiment a stent with flared ends and a filter is described. 
     In one embodiment a stent with flared ends, a filter, and a connecting structure is described. 
     In one embodiment a stent with a filter is used to treat a vascular condition, and the filter is used to catch thrombus dislodged by the stent. 
     In one embodiment a stent with a filter is used to treat a vascular condition, and the filter is used to hold occlusive embolic material. 
     A stent with an integrated filter may eliminate the need for a separate filter, making the interventional procedure easier since there is no need to deploy and retrieve a separate filter. 
     The integrated filter portion of the stent may also be used for other purposes, such as to occlude a vessel. For example the filter may be filled with embolic coils or other embolic agents that block blood flow beyond the filter portion, occluding the vessel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which 
         FIGS. 1-2  illustrate a stent. 
         FIGS. 3A, 3B, and 4  illustrate a stent with flared loops. 
         FIGS. 5-7, 8A and 8B, and 9-16  illustrate various embodiments of stents with an integral filter. 
         FIG. 17A-17B  illustrate a mandrel used to form a stent with an integral filter. 
         FIG. 18  illustrates a delivery device capable of delivering any of the filter stent embodiments of the present invention. 
         FIG. 19  illustrates an embolic delivery device delivering embolic coils to the filter portion of a filter stent of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, 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 be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements. 
     US Pub. No. 2013/0245745 A1 describes multiple stent embodiments, including single layer and dual layer stents, and is hereby incorporated by reference in its entirety. 
     In various stenting procedures filters (or embolic protection devices) are first deployed at a distal location to catch thrombus dislodged when the stent is in place. A stent is subsequently introduced and expanded at a location proximal to the filter (preferably proximal and upstream of the filter), allowing the filter to catch any thrombus dislodged by the stent. This procedure is useful, for example, to open up an artery when there is thrombus formation in the artery. The following embodiments disclose a stent with an integral filter which would eliminate the need of a separate filter. 
     The filter basket described in the following embodiments may be comprised of a nitinol wire mesh comprising one or more braided wires. The filter may utilize radiopaque material for ease of visualization. In one example one or more of the filter mesh wires utilize a radiopaque wire (i.e. tantalum). In another example radiopaque marker bands or marker coils are placed in predetermined locations in the filter mesh. In another example the struts of the filter basket are comprised of a radiopaque material. In another example the struts of the filter basket utilize radiopaque marker bands or marker coils. 
     The stent  100  shown in  FIGS. 1-2  is a single layer stent. In one example the stent is a self-expanding, one-layer stent comprised of a single filament wound into braided pattern. In another example the stent is a single layer comprised of a mesh of different wires interwoven together. 
     In another example, the stent is a self-expanding dual layer stent  200  with an inner layer or component  202  and an outer layer or component  100 , see U.S. Pub. No. 2013/0245745 A1, which is incorporated above. Preferably, the inner layer  202  has a lower porosity than the outer layer  100  (i.e. outer layer has larger gap or whole sizes). The outer component can have flared distal ends at both ends of the stent. In one example both the inner layer and outer layer are comprised of a mesh of multiple wires. In another example the inner layer is a mesh of multiple wires while the outer layer is comprised of one wire wound upon itself. These flared ends provide an anchor point within the vessel thus securing the stent within the blood vessel and preventing migration. 
       FIGS. 3A, 3B, and 4  illustrate a dual layer stent  200  comprising an inner layer  202  and outer layer  100 . The inner layer  202  is composed of wires  204  woven or braided into a mesh tube shape, and the outer layer  100  is composed of one or more wires  102  woven or braided into a tube shape. The outer layer  100  includes proximal and distal radially-flared loops  104  that may include one or more radiopaque coils  106  (e.g., radiopaque wire coiled around the wire of the loop  104 ) used for visualization. A tantalum wire  105  may be interwoven between the inner and outer layers to bind the layers together and to promote visualization. One or more attachment members  206  (e.g., coils) may also be connected in various locations throughout the stent  200  (e.g., locations along the length of the stent) to connect the inner and outer layers of the stent. Please note the pairs of flared loops  104  shown in  FIG. 4 . In one example one or more of the radially, oppositely located “pair” of loops  104  is shorter than an adjacent “pair”. 
       FIGS. 5-8  show an embodiment of a stent  300  composed of a stent portion  302  and a filter portion  304 . The stent portion  302  can be the stent  100  shown  FIGS. 1-2  or the dual layer stent  200  shown in  FIGS. 3A, 3B, and 4 . The filter portion  304  (also referred to as a mesh or filter basket) may be a generally concave shape, a conical shape, a bulbous, a rounded shape, a cylinder shape (with a mesh end), or a similar shape that is closed so as to block thrombus moving distally from a delivery catheter and stent. 
     In one example the stent portion  302  and filter portion  304  are two separately produced components which are subsequently attached to each other. The filter portion  304  can be directly welded or adhesively bonded to one end of the stent  300  (e.g., the distal end). Thus the wire or wires comprising the stent portion  302  at one end are connected to the wire or wires comprising the filter portion  304  (e.g., at intersecting points). Alternately, the filter portion  304  can be mechanically attached to one end of the stent portion  302  via mechanical ties (e.g., wires tied around wires from both portions) or coils which are tied to or wound around the intersection of, respectively, the stent portion wire/wires and the filter portion wires. 
     In another example the stent portion  302  and filter portion  304  are part of one commonly manufactured component. For example, the stent with integral filter  300  is wound over a mandrel in which the mandrel has a cylindrical and a conically shaped portion (or whatever filter portion shape is desired). One or more wires are wound over the cylindrical part of the mandrel to form the tubular stent portion  302 , and one or more wires are wound over the conical portion of the mandrel to make up the filter portion  304 . In this way, the filter portion  302  and stent portion  304  are comprised of the same wires, just wound over differently shaped portions of the mandrel to produce the respective shapes. 
     Again, the filter portion  304  is not limited to a conical shape. In one example it is a hemispherical shape in which a hemispherical-shaped mandrel section  303  is used to braid the filter portion  304  and the cylindrical mandrel portion  301  is used to braid the stent portion  302 , as shown in  FIG. 17A .  FIG. 17B  illustrates a conically-shaped mandrel portion  305  on which the conically-shaped filter portion  304  is woven. 
       FIGS. 6 and 7  illustrate another embodiment of a stent  300 A comprised of a stent element  302 , a filter element  304 , and a plurality struts  306  (e.g., 4) which connect the stent portion  302  and the filter portion  304  together. In one example, the struts  306  are formed from wires braided or woven into the filter portion  304  and which are woven or connected (e.g. via welding, mechanical attachments, or adhesive). In another example, the struts  306  are part of the stent portion  302  and are wound or woven with the stent wires and connected to the filter portion  304  at its open end. This arrangement is possible where the stent portion  302  is wound and then several of the wires are cut to produce an open end of the stent portion  302 , allowing the wires which are not cut to become the struts  302 . The struts  302  are connect to the filter portion  304  via welding, mechanical attachment, or adhesive. In another example the struts  306  are separate from both the filter portion  304  and stent portion  302 , and are instead comprised of separate wires spanning the gap and being affixed to the wires of the two portions. In another example, only some of the wires at an end of the stent portion  302  form the plurality of struts  306 , leaving several uncut wires to form the struts  306 . These wires forming the struts  306  can then form part of the mesh of wires comprising filter portion  304 . Finally, the wires forming either the outer stent layer or inner stent layer can form the struts  306  and can continue into the filter portion  304  so as to be woven or braided into the filter portion  304 . 
       FIGS. 8A-8B  illustrates another embodiment of a stent  300 B comprising a stent portion  302 , connecting element  308 , a plurality of struts  306 , and a filter portion  304 . The connecting element  308  is comprised of at least two distally converging legs  308 A and preferably at least four distally converting legs  308 A as shown in  FIGS. 8A and 8B . In one example, each of the legs  308 A of connecting element  308  is comprised of two or more wires which are connected to the stent portion  302  at one end and converge a common point at the end opposite the stent portion  302 . The plurality of struts  306  can connect between locations on each of the legs  308 A and the filter portion  304 . 
       FIG. 9  illustrates another embodiment of a stent  300 C having a stent portion  302  similar to the previously described dual layer stent  200  of  FIGS. 3A-4 , including the flared loops  104  located at both proximal and distal ends of the stent portion  302 . A filter portion  304  is attached to the end of the flared loops  104 . One end of the wire forming the filter portion  304  may be attached to the apex  104 A of the ‘V’ shape of the flare. In embodiments with longer and shorter loops  104  at each end, the wires of the filter portion  304  may be attached to only the apexes of the longer loops  104 . Alternately, the wires of the filter portion  304  may be attached to the apexes  104 A of both the longer and shorter loops  104 . Adhesive bonding, mechanical attachment, or welding may be used to attach the wires of filter portion  304  to the flared loops  104 . 
       FIGS. 10-11  are variations of the embodiment of  FIG. 9  in which the filter portion  304  is connected to the apex  104 A of the loops  104  via connecting elements  310 , which are elongated struts similar to those described in earlier embodiments. In the embodiment of the stent  300 D, the connecting elements  310 A are inwardly curved towards a center axis of the device, while the stent  300 E includes substantially straight connector elements  310 B. Preferably, at least two connecting elements  310  are used to connect to the filter portion  304  (e.g., 2, 3, 4, 5, or 6 elements  310 ). 
       FIG. 12  illustrates another embodiment of a stent  300 F having a connecting element  308  composed of a plurality of elongated leg members  308 A that connects between the apexes  104 A of the loops  104  and struts  306 . The stent  300 G of  FIG. 13  is generally similar to stent  300 F, except that the legs  308 A of the connecting member  308  are inwardly curved towards a center axis of the stent  300 G. 
       FIGS. 14 and 15  illustrate stent embodiments ( 300 H and  300 I, respectively) similar to those shown in  FIGS. 5-6 , except that the stent  300 H or  300 I is a dual layer stent with flared loops  104 , as previously described in this specification. The filter portion  304  is either connected directly to the stent portion  302  or to the stent portion  302  via two or more struts  306 , allowing the filter portion  304  to expand to a diameter similar to that of the stent portion  302 , as opposed to the larger radius of the flared loops  104 . The filter portion  304  may be attached to either the inner layer  202  or the outer layer  100  of the stent portion  302 . In one example, filter portion  304  may be integrally wound with the inner layer  202  of the stent portion  302  in the manner shown and described earlier with regard to  FIGS. 17A-17B . 
       FIG. 16  illustrates an embodiment of a stent  300 J utilizing the dual layer stent  200  of  FIGS. 3-4  for the stent portion  302 . A connecting structure  308  connects to either the inner layer  202  or the outer layer  100  of the stent  300 J, and not to the loops  104  as in the embodiment of  FIGS. 12-13 . Struts  306  link the connecting structure  308  to the filter portion  304 . As with previous embodiments, the connecting structure  308  can take on any number of shapes, such as a conical shape formed from a plurality of leg members. This embodiment is thus similar to that shown in  FIGS. 8A-8B , except that the stent  300 J includes an outer stent layer  100  with flared loops  104 . 
     The stent embodiments described herein and shown in  FIGS. 1-16  can be used with embolic coils that are placed within the filter portion to cause occlusion through the stent portion. For example,  FIG. 19  illustrates an embolic coil delivery device  162  that has delivered one or more embolic coils  160  (and/or any other embolic material) within the filter portion  304  of any of the stent filter embodiments  300  disclosed in this specification. The embolic coil delivery device  162  can be advanced through a pre-placed catheter or sheath used by the filter stent delivery device  150 , or can be separately advanced over a guidewire to a location within the deployed filter stent  300 . 
     This arrangement may be used to close down a vessel by introducing the stent to the target vessel location and delivering the coil within in the filter portion, thereby blocking or occluding the blood flow through the blood vessel. This technique may also be useful to treat an aneurysm or other vessel malformation by positioning a stent into the aneurysm or malformation and delivering the embolic coils within the filter portion at the distal end of the filter stent in order to occlude flow beyond the filter portion and into the aneurysm or malformation. The procedure described may be used for occluding any one of: an aneurysm, left atrial appendage, fallopian tube, patent ductus arteriosus, or other occlusive procedures. In one example the stent and filter are pushed from the catheter or the sheath of the catheter is retracted to expose the stent/filter. Embolic coils are then introduced through the catheter and deployed into the filter basket. 
       FIG. 18  illustrates one example embodiment of a delivery device  150  capable of delivering any of the filter stents  300  of the present invention. The delivery device  150  includes an inner, elongated core member  152  on which the filter stent  300  is compressed or disposed over. An outer sheath  154  is positioned over the filter stent  300  during positioning so as to maintain the filter stent  300  in its compressed configuration. Once the target location has been reached, the outer sheath  154  can be retracted by the physician, allowing the filter stent  300  to expand. The delivery device  150  may include a guidewire passage so that it alone can be advanced over the guidewire to the target location. Alternately, the delivery device can be advanced through a larger catheter or sheath that is already positioned at the target location. 
     Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.