Abstract:
An intravascular material removal device that removes material from a vessel wall and creates flow dynamics that draw the material into a catheter device for removal from the vessel is provided. A collapsible device that provides a relatively low delivery profile while being expandable in use to adapt to varying and variable vessel diameters is also provided. A spiral configured material removing element is provided that can adapt to varying vessel diameters and to remove material forming blockages or occlusions from the inner wall of a vessel.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a divisional of U.S. application Ser. No. 10/423,266 filed Apr. 25, 2003, the entire contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to a device for removing material such as thrombus, plaque, and clots, from a body lumen such as a blood vessel.  
       BACKGROUND OF THE INVENTION  
       [0003]     Plaque, fat deposits, calcium deposits, thrombus, blood clots, etc. deposited on the inner walls of the blood vessel may cause narrowing or occlusion of the blood vessels, cutting off or restricting blood flow and/or presenting a dangerous condition in which the material may break off and travel through the vasculature causing further blockages, clots or embolisms.  
         [0004]     A variety of devices have been proposed for forming a channel in or removing such material from a vessel.  
         [0005]     Guidewires have been used to channel through such deposits and a balloon passed over the guidewire is then used to form an opening. This method, however, does not provide a means for removing the material deposited on the vessel wall. Also material can break off and move downstream forming a clot or other blockage.  
         [0006]     Another technique has used laser ablation to form channels in the blockages. The laser energy atomizes or blasts away particles of occluding materials. Laser techniques currently used carry with them the risk of overheating tissue and burning holes in the vessel walls. The openings formed in the blockages are also limited by the size of the laser. The laser treatment is typically followed with ballooning of the occluded region.  
         [0007]     Some techniques have used percutaneously placed catheter devices to physically remove material. The percutaneous techniques avoid direct surgery at the occluded site and avoid creation of a large opening at the site of insertion into the blood vessel. Rotating cylindrical cutters have been used to shave off material from the vessel wall. These devices have been problematic where the cut material moves downstream forming another blockage or clot. Such devices also have not worked particularly well on thrombus or clots. Also, the large cutting head size relative to the delivery path, that is required to effectively remove material from the vessel wall, makes the cutting device difficult to deliver. A variety of cutting head configurations have been proposed including a conical cutting head with aspiration for retrieving cut material. A screw like conical cutting head has also been proposed.  
         [0008]     A balloon expandable cutting device has been proposed so the diameter of the cutting head may be varied to accommodate blood vessels having a wide range of internal diameters. However, these devices require actuation to expand or contract the cutting heads and they do not adapt sufficiently to change in circumference of the vessel along its length or as the device is advanced through the vessel while cutting.  
         [0009]     Another device uses highly pressurized fluid to remove material. This technique includes a risk of perforation and damage to vessel from the high pressure jetted fluid. It is also a slow process that takes significant physician and patient table time to perform.  
         [0010]     Other devices have used inflated balloons on each side of the occluded portion of the vessel to be treated, to stop flow of blood while a mechanism such as a rotating cutter, stream of fluid or rotating brush is used to dislodge particles. These devices are relatively complex requiring placement of a balloon on each side of the blockage.  
         [0011]     Accordingly it would be desirable to provide a device for removing material from a body lumen that has a relatively small delivery profile and a relatively simple delivery procedure. It would also be desirable to provide a device for removing material from a body lumen that is adaptable to varying sizes of blood vessels diameters. It would also be desirable to provide such an improved device that reduces the risk of dislodged or cut materials moving downstream and forming blockages or clots.  
       SUMMARY OF THE INVENTION  
       [0012]     An embodiment according to the present invention provides an intravascular material removal device that removes material from a vessel wall and creates flow dynamics that draw the material into a catheter device for removal from the vessel. A collapsible device provides a relatively low delivery profile while being expandable in use to adapt to varying and variable vessel diameters.  
         [0013]     In one embodiment according to the present invention, the device comprises a plurality of bristles formed in a spiral-like configuration along the length of an elongate member. In use the elongate member is rotated so that the spiraled bristles create a flow pattern in a proximal direction that draws materials dislodged by the bristles or brush towards a catheter from which the elongate member extends.  
         [0014]     The device has a material removing element that may be selected from a plurality of material removing elements having different properties, e.g., stiffness, flexibility, bristles of various sizes, etc for removing different types of material from gelatinous deposits like thrombus to harder deposits such as calcium deposits.  
         [0015]     Another aspect according to the invention may provide a material removal device having bristles constructed of a material that permits the bristles to flex to conform to the vasculature as it is moved through or is deployed in a vessel, and that is sufficiently stiff to remove desired material from the vessel wall.  
         [0016]     Another aspect according to the invention, provides a spiral configuration where the length of the bristles at a distal end portion are shorter that the length of the bristles at a proximal end portion such that the overall diameter of the device is greater at the proximal end portion than at the distal end portion.  
         [0017]     In one variation of the embodiment, the bristles are retractable so that the delivery profile of the device may be reduced for delivery through the vasculature. The device in one variation provides bristles that may flex when retracted into a catheter. Another embodiment provides an inner elongate member with a plurality of bristles formed in a spiral-like configuration attached to the inner member and an outer member positioned over the elongate member having at least one opening through which the bristles may extend. The outer member and inner member are configured to move axially with respect to each other so that the outer member engages to retract the bristles to provide a smaller radius device or alternatively permit the bristles to extend through the opening to a produce a larger radius device.  
         [0018]     Aspiration may be provided through a catheter into which material is drawn and/or through the material removing element itself which may have openings through slots in an outer member and through a series of bristles.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1A  is a side view of an embodiment of a device for removing material deposited on vessel walls.  
         [0020]      FIG. 1B  is a view from the proximal end of the device of  FIG. 1B   FIG. 2A  is a side view of an embodiment of a device for removing material deposited on vessel walls.  
         [0021]      FIG. 2B  is a side view, partial cross section of a portion of the device of  FIG. 2A  in a partially collapsed position.  
         [0022]      FIG. 2C  is a side view, partial cross section of a portion of the device of  FIG. 2A  in an expanded position.  
         [0023]      FIG. 2D  is a schematic side view of a portion of the device of  FIG. 2A .  
         [0024]      FIG. 3  illustrates the device of  FIG. 1A  in use, percutaneously positioned in a partially blocked iliac artery of a patient.  
         [0025]      FIG. 4  illustrates the device of  FIGS. 2A-2D  in use, percutaneously positioned in a blocked iliac artery of a patient.  
         [0026]      FIG. 5A  is a side view of an embodiment of a device for removing material deposited on vessel walls.  
         [0027]      FIG. 5B  illustrates the device of  FIG. 5A  in use, percutaneously positioned in a partially blocked iliac artery of a patient. 
     
    
     DETAILED DESCRIPTION  
       [0028]     Referring to  FIGS. 1A and 1B , an intravascular material removing device  20  is illustrated including a delivery catheter  25  and an elongate member  30  with a plurality of bristles  32  formed in a spiral arrangement along the length of the elongate member  30 . The elongate member  30  is illustrated in a position extending out of a delivery catheter  25 . The limits of the arc circumscribed by the bristles  32  gradually taper from a proximal portion  35  to a distal end portion  36  of the elongate member  30 . When the elongate member  30  is retracted into the delivery catheter  25 , the bristles  32  may flex or bend so that they fit within the delivery catheter  25 . Thus the elongate member  30  is retractable into a catheter having a smaller diameter than the outer diameter of the elongate member when the bristles are not constrained.  
         [0029]     As illustrated in  FIG. 3 , in use, the elongate member is delivered percutaneously through the catheter  25  to a blocked portion  71  of a vessel  70 . In this particular embodiment, an abdominal aorta is illustrated with one of the iliac vessels partially blocked by material  75 . Expanded within a vessel, the bristles  32  adapt to a varying diameter vessel and are in position to remove material. The elongate member  30  is placed adjacent the material  75  and is rotated by a motor (not shown) coupled to the elongate member  30  located external the patient&#39;s body. As the elongate member  30  is rotated, it is advanced into and through the blocked material  75 , the narrower distal end  36  first and then the wider proximal end portion  35 , the bristles  32  being flexible, adapting to the diameter of the vessel as the elongate member  30  is moved within the vessel. The bristles  32  break the material  75  away from the vessel wall and create a pressure gradient or flow in a direction towards the catheter  25  and proximal end portion  35 , like a screw pump. The arrow A 1  illustrates the normal direction of the flow of blood while the arrows A 2  illustrate the direction of flow of material when the device  20  is in use. The catheter  25  may also provide aspiration to further draw the material into the catheter  25 .  
         [0030]     The bristles  32  may be made of a number of different materials such as nylon or a metal. The stiffness/flexibility, hardness/softness, abrasiveness, thickness of, number of and configuration of the bristles  32  may be selected depending upon the application, e.g., the material to be removed or the condition of the vessel in which it is to be used. For example, stiffer bristles would be used for fibrotic material or calcium deposits whereas for blood, thrombosis and gelatinous material, a softer bristle may be selected. A plurality of material removing elements may be provided, each having a different property that may be selected based upon condition of the vessel to be treated, i.e., the type of material deposited on the vessel wall, the type of vessel, or the toughness, resilience or other property of the vessel or vessel wall.  
         [0031]     Referring to  FIGS. 2A-2D  an intravascular material removal device  40  is illustrated. The device  40  comprises an inner member  41  having bristles  42  coupled to the inner member  41 , and a cylindrical outer member  45  having a distal portion  48  including slots  46  formed in the outer member  45  in a generally spiral configuration along the length of the distal portion  48 . The bristles  42  of the inner member  41  are affixed at an angle or alternatively are hinged or otherwise coupled to the inner member  41 , also in a spiral configuration. The limits of the arc circumscribed by the bristles  42  gradually taper from a proximal portion  43  to a distal end portion  44  of the inner member  41 . The bristles  42  extend through the slots  46  in the outer member  45 . The bristles  42  are formed of a biocompatible material such as, e.g. a nylon material. The biocompatible material may be selected based on factors such as stiffness depending on its desired application, the type or characteristics of material that is to be removed or the type or characteristic of the vessel in which it is to be used such as e.g. described above with reference to device  20 .  
         [0032]     The inner member  41  slides coaxially within the outer member  45  to expand or collapse, or extend or retract the bristles  42  extending out of the slots  46 . As illustrated in  FIG. 2B , the device is in a retracted position in which the radius of the device  40  is reduced. In this position the distal end  44  of the inner member  41  extends distally toward the distal end  48  of the outer member  45 . The bristles  42  are drawn into the slots  46  by edges  49  of the slots  46 .  
         [0033]     As illustrated in  FIGS. 2A and 2C , the device  40  is in a fully expanded position with the bristles  42  extending out of the slots  46 . In this position, the distal end  44  of the inner member  41  is moved in a proximal direction with respect to the distal end  48  of the outer member  45  so that the bristles  42  are not constrained by the edges  49  of the slots  46  and extend to their full radius. Expanded within a vessel, the bristles  42  adapt to a varying diameter vessel and are in position to remove material. The bristles  42  are ideally flexible enough to avoid damage when expanding to the vessel diameter, while being stiff enough to removed the deposited material.  
         [0034]      FIG. 4A  illustrates a device  40  in use in removing a blockage  110  from an iliac artery branch vessel  100 . The device is percutaneously passed in a retracted position within a catheter  50 , into the right iliac artery  105  upstream through the abdominal aorta  103  and back down into the left iliac branch vessel  100 . The device  40  is initially positioned out of the catheter  50  and in the artery  105 , in a retracted position as illustrated in  FIG. 2B , and upstream and adjacent the blockage  110 . Once the device  40  is in position, the inner member  41  is moved proximally with respect to the outer member  45  to expand the device  40  so that the bristles  42  engage the inner wall of the vessel  100 . The inner member  41  may be moved to partially or completely release the bristles  42  from engagement with the edges  49  of the slots  46  depending on the desired device radius. The bristles  42  further adapt to the diameter of the vessel. The device  40  is then rotated about its axis a so that the bristles  42  scrape off the material and create a flow like a screw pump in an upstream direction towards the distal end  52  of the catheter  50 . According to one variation of this embodiment the inner member  41  and outer member  45  have some clearance between each other so that irrigation and aspiration may be provided through the slots  46  as shown for example by arrow A 5  in  FIG. 2C . Alternatively or in addition, irrigation and aspiration may be provided through the distal end of the catheter  50 . Thus, a screw pump like creation of a flow pattern moves material upstream and thereby avoids loosened or cut materials from moving downstream. The bristles  42  may be sufficiently flexible that the device  40  may retracted into the catheter  50  in its fully or partially expanded position during delivery or removal of the device  40 .  
         [0035]     Referring to  FIGS. 5A and 5B , an intravascular material removing device  120  is illustrated including a delivery catheter  125  and an elongate member  130  with a plurality of bristles  132  formed in a spiral arrangement along the length of the elongate member  130 . The device  120  is constructed in a manner similar to the device  20  described above with reference to FIGS.  1 A-B and  FIG. 3 . The elongate member  130  is illustrated in a position extending out of a delivery catheter  125  with the proximal portion  135  of the elongate member  130  positioned within the distal portion  126  of the catheter  125 . The limits of the arc circumscribed by the bristles  132  gradually taper from a proximal portion  135  to a distal end portion  136  of the elongate member  130 , and such that when the elongate member  130  is retracted into the delivery catheter  125 , the bristles  132  fit within the delivery catheter  125 .  
         [0036]     As illustrated in  FIG. 3 , in use, the elongate member  130  is delivered percutaneously through the catheter  125  to a blocked portion  171  of a vessel  170 . In this particular embodiment, an abdominal aorta is illustrated with one of the iliac vessels partially blocked by material  175 . The elongate member  130  is placed adjacent the material  175  and is rotated by a motor (not shown) coupled to the elongate member  130  located external the patient&#39;s body. The bristles  132  break the material  175  away from the vessel wall and create a pressure gradient or flow into the catheter  125  wherein the distal portion  126  of the catheter  125  envelopes the proximal portion  135  of the elongate member  130  and bristles  132 , thereby providing an impeller to further direct material into the catheter  125 .  
         [0037]     The devices of embodiments of the invention are illustrated in use in a blocked iliac artery. Other blocked vessels are contemplated for treatment with the device, including for example, without limitation, the carotid artery, superficial femoral artery and popliteal artery.  
         [0038]     While the invention has been described with reference to particular embodiments, it will be understood to one skilled in the art that variations and modifications may be made in form and detail without departing from the spirit and scope of the invention.