Abstract:
An embolic protection device, the device expandable from a first low profile configuration to a second expanded configuration, the device adapted for implantation body lumen, the device comprising an expandable support structure comprising radially expandable tubular first and second end portions and a laterally expandable central portion extending between the first and second end portions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority to U.S. Patent Provisional Application No. 61/559,297 filed Nov. 14, 2011, the entire contents of which are hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention generally relates to embolic protection devices and methods of making and using the same. 
         [0003]    Heart disease is a major problem in the United States and throughout the world. Conditions such as atherosclerosis result in blood vessels becoming blocked or narrowed. Aortic valve stenosis (AVS) is a disease of the heart valves in which the opening of the aortic valve is narrowed. 
         [0004]    Minimally invasive endovascular aortic arch and valve procedures such as transcatheter aortic valve implantation (TAVI) have become a therapeutic option for patients with severe symptomatic aortic stenosis. TAVI is a procedure that involves implantation of a collapsible prosthetic valve using a catheter-based delivery system. This type of prosthesis can be inserted into the patient through a relatively small incision or vascular access site, and can be implanted on the beating heart without cardiac arrest. 
         [0005]    Complications of this procedure include embolization of plaque or thrombus. Embolization can occur from the valve during balloon valvuloplasty and valve deployment or embolization of aortic atheroma can occur during device passage. 
         [0006]    Embolizations can be carried downstream to lodge elsewhere in the vascular system. This is particularly problematic in both the left and the right carotid arteries. Such emboli can be extremely dangerous to the patient, capable of causing severe impairment of the circulatory system. Depending on where the embolic material is released, a heart attack or stroke could result, or in the event peripheral circulation is severely compromised, the amputation of a limb may become necessary. Thrombus formation can be particularly problematic in structural heart interventional procedures, particularly in minimally invasive heart valve placement procedure and TAVI procedures. 
         [0007]    Cerebral embolism or stroke is the sudden blocking of an artery by a thrombus or clot, or other foreign material which is carried to the site of lodgment via blood flow. Cerebral embolism is one of the major complications of transcatheter structural heart procedures or minimally invasive structural heart procedures. 
         [0008]    A number of devices, termed embolic protection devices, have been developed to filter out this debris and reduce the risk of cerebral embolism. 
         [0009]    Conventional embolic protection devices are used mainly during the carotid vascular interventional procedure whereas the risk of a thrombus embolism is due to carotid vascular angioplasty or stenting. 
         [0010]    There remains a need in the art for an embolic protection device that provides effective protection during a transcatheter aortic valve implantation procedure, but also can be used for an extended protection from thrombus embolism after the procedure. 
         [0011]    These and other aspects, embodiments and advantages of the present disclosure will become immediately apparent to those of ordinary skill in the art upon review of the Detailed Description and Claims to follow. 
       SUMMARY OF THE INVENTION 
       [0012]    In one embodiment, the present invention relates to an embolic protection device, the device expandable from a first low profile configuration to a second expanded configuration, the device adapted for implantation body lumen, the device comprising an expandable support structure comprising radially expandable tubular first and second end portions and a laterally expandable central portion extending between said first and second end portions. 
         [0013]    In another embodiment, the present invention relates to an embolic protection device, the device expandable from a first low profile configuration to a second expanded configuration, the device adapted for implantation in a left subclavian artery and brachiocephalic artery and right subclavian artery, and to cover the right and left carotid artery, the device comprising a first end portion configured and arranged for disposition in the left subclavian artery, in the expanded configuration the first end portion is sealingly engageable to a wall of the left subclavian artery, a second end portion configured and arranged for disposition in the brachiocephalic artery and the right subclavian artery, in the expanded configuration the second portion is sealingly engageable to a wall of the right subclavian artery and a middle portion extending between the first end portion and second end portion, in the expanded configuration, the middle portion covers the right and the left carotid artery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective side view of one embodiment of an embolic protection device according to the invention in its expanded state. 
           [0015]      FIG. 2  is a top view of the device shown in  FIG. 1  in its expanded state. 
           [0016]      FIG. 3  illustrates a device similar to that shown in  FIGS. 1 and 2  expanded in the left and right subclavian arteries and covering the left and right carotid arteries. 
           [0017]      FIG. 4  is a side view of a guidewire disposed in the right and left subclavian arteries and through the brachiocephalic and the aortic arch. 
           [0018]      FIG. 5  is a side view of a catheter assembly and embolic protection device disposed in the right and left subclavian arteries and through the brachiocephalic and the aortic arch. 
           [0019]      FIG. 6  is a side view of an embolic protection device disposed in the right and left subclavian arteries and through the brachiocephalic and the aortic arch. The catheter is being withdrawn from the right subclavian artery. 
           [0020]      FIG. 7  is a side view of an embolic protection device disposed in the right and left subclavian arteries and through the brachiocephalic and the aortic arch. The device is disposed on a guidewire. 
           [0021]      FIG. 7A  is a top down view of the arteries and device as shown in  FIG. 7 . 
           [0022]      FIG. 8  is a side view of an embolic protection device disposed in the right and left subclavian arteries and through the brachiocephalic and the aortic arch wherein the device has been delivered from the left radial artery. The device is shown disposed on a guidewire. 
           [0023]      FIG. 9  is a side view of one embodiment of an embolic protection device disposed on a guidewire. 
           [0024]      FIG. 9A  is an enlarged longitudinal cross-sectional view of an embolic protection device taken at  9 A in  FIG. 9 . 
           [0025]      FIG. 10  is a partial side view of the proximal end of one embodiment of an embolic protection device having a recapture mechanism and a corresponding retrieval mechanism on the right side of the figure. 
           [0026]      FIG. 11  is a partial side view of the proximal end of one embodiment of an embolic protection device having an alternative recapture mechanism and a corresponding retrieval mechanism on the right side of the figure. 
           [0027]      FIG. 12  is a partial side view of the proximal end of one embodiment of an embolic protection device having an alternative recapture mechanism and a corresponding retrieval mechanism on the right side of the figure. 
           [0028]      FIG. 13  is a side view of one embodiment of an embolic protection device shown disposed within a delivery device. 
           [0029]      FIG. 14  is a side view of one embodiment of an embolic protection device shown disposed on a mandrel. 
           [0030]      FIG. 15  is a side view of an alternative embodiment of an embolic protection device having a tapered structure wherein the larger diameter end is configured and arranged for disposal in the brachiocephalic artery and the smaller diameter end is configured and arranged for disposal in the left subclavian artery. 
           [0031]      FIG. 15A  is a side view illustrating a device similar to that shown in  FIG. 15  disposed in the brachiocephalic artery, through the aortic arch and into and the left subclavian artery. 
           [0032]      FIG. 16  is a top down view of an alternative embodiment of an embolic protection device. 
           [0033]      FIG. 17  is a side view of an embolic protection device similar to that shown in  FIG. 16 . 
           [0034]      FIG. 18  is a top down view of an alternative embodiment of an embolic protection device. 
           [0035]      FIG. 19  is a top down view of an alternative embodiment of an embolic protection device. 
           [0036]      FIG. 20  is a side view of an alternative embodiment of an embolic protection device. 
           [0037]      FIG. 21  is a side perspective view of an alternative embodiment of an embolic protection device including a frame  82  and a membrane  84  disposed on the inner surface of the frame  82 .  FIG. 18  is a top down view of an alternative embodiment of an embolic protection device. 
           [0038]      FIG. 22  is a side perspective view of one embodiment of a mandrel which can be employed to form an embolic protection device which is radially expandable at either end and laterally expandable in the middle. 
           [0039]      FIG. 23  is a top down view of a mandrel similar to that shown in  FIG. 22 . 
           [0040]      FIG. 24  is a side perspective view of a mandrel similar to that shown in  FIG. 22  having an embolic protection device disposed thereon. 
           [0041]      FIG. 25  is a side view of a mandrel similar to that shown in  FIGS. 22 and 23  having an embolic protection device disposed thereon. 
           [0042]      FIG. 26  illustrates an alternative method and device for forming an embolic protection device, the method and device including shaping dies. 
           [0043]      FIG. 27  is a top down view of  FIG. 26 . 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    While embodiments of the present disclosure may take many forms, there are described in detail herein specific embodiments of the present disclosure. This description is an exemplification of the principles of the present disclosure and is not intended to limit the disclosure to the particular embodiments illustrated. 
         [0045]    Turning now to the figures,  FIG. 1  is a perspective side view illustrating one embodiment of an embolic protection device  10  according to the invention. Device  10  includes radially expandable end portions  12 ,  14  and a laterally expandable central portion  16 . The radially expandable end portions  12 ,  14  can be clearly seen in their expanded state.  FIG. 2  is a top down view illustrating the same device as that shown in  FIG. 1  but the laterally expandable central portion  16  can be more clearly seen in its expanded state. Device  10  is closed at either end. 
         [0046]    The device is configured and arranged for placement in the aortic arch area and is disposed and deployed in the left subclavian artery and the right subclavian artery of the brachiocephalic artery wherein the central portion  16  of the device  10  covers the left and right carotid arteries for embolic protection. 
         [0047]      FIG. 3  illustrates device  10  deployed and expanded in a patients vasculature in the aortic arch area  18 , namely, end portion  12  of device  10  is radially expanded in the right subclavian artery  20  and engages the wall thereof, end portion  14  of device  10  is radially expanded in the right subclavian artery  22  and engages the wall thereof, and the middle portion  16  of device  10  is expanded and covers the right carotid artery  24  and the left carotid artery  26  and provides protection from emboli that can be generated during structural heart procedures such as placement of an implantable prosthesis in the heart. 
         [0048]    The device can be delivered through the vasculature via a catheter delivery device which will be explained in more detail below, via either the left radial artery through the left subclavian artery to the aortic arch or via the right subclavian artery. 
         [0049]      FIGS. 4-7  illustrate one method of delivering the device via the right radial artery into the right subclavian artery  22  passing through the brachiocephalic artery and the aortic arch  18  and finally into the left subclavian artery  28 . 
         [0050]    A guidewire  30  is first delivered via the left radial artery into the left subclavian artery  28  and advanced through the aortic arch  18  into the brachiocephalic artery  20  and finally into the right subclavian  22 . 
         [0051]    A delivery catheter  34  comprising a sheath  36  in which device  10  is seated for delivery is then advanced over guidewire  30  from the right radial artery into the right subclavian artery  22  and advanced through the aortic arch  18  into the brachiocephalic artery  20  and finally into the left subclavian artery  28  wherein device  10  can be expanded and deployed. In the embodiments shown in  FIGS. 4-7  guidewire  30  has a distal tip that is in the form of a flexible spring coil. An example of a similar guidewire are frontline guidewires available from Boston Scientific and sold under the trademarks of ChoICE®, Luge™, IQ® and Forte®, for example. These guidewires come in diameter sizes of 0.014″, 0.018″ or 0.035″ with a 0.014″ diameter guidewire being most suitable. 
         [0052]    Once in position, sheath  36  can be pulled back to expand the device  10  so that end portions  12 ,  14  are disposed in the right subclavian artery  22  and the left subclavian artery  28  and the middle portion  16  covers the right carotid artery  24  and left carotid artery  26  as shown in  FIG. 7 .  FIG. 6  illustrates sheath  36  partially pulled back form device  10  wherein end portion  14  of device  10  is shown expanded in the left subclavian artery  28 .  FIG. 6  illustrates the sheath  36  pulled back completely from device  10  wherein end portion  12  of device  10  is now expanded in the right subclavian artery  22  and middle portion  16  has been laterally expanded in the aortic arch area  18  to cover the right carotid artery  24  and the left carotid artery  26 . 
         [0053]      FIG. 7A  is a top down view taken from  FIG. 7  wherein it can be seen that the middle portion  16  of device  10  which is laterally expanded covers the left carotid artery  26  and the radially expanded end portions  12  and  14  can be seen in the brachiocephalic artery  20  and the left subclavian artery  28  respectively. 
         [0054]      FIG. 8  illustrates device  10  having been delivered via the left radial artery through the left subclavian artery  30 . The distal flexible spring coil  31  of the guide catheter is shown in the right subclavian artery  22  in this case. The process for delivering and deploying the device is in all other respects the same as that discussed with respect to  FIGS. 4-7 . 
         [0055]    Also in the embodiments shown in  FIGS. 4-8 , device  10  is closed at either end with bands  38 ,  40  such as radiopaque marker bands. 
         [0056]    The device  10  can be secured to a guidewire  30  by crimping band  38  onto guidewire  30  as shown in  FIG. 9 . Band  40  is a hollow ring in which guidewire  30  is slidable therein as shown in  FIG. 9A . 
         [0057]    The assembly can be constructed such that the guidewire  30  is separate from and slidable within device  10 , or device  10  can be fixedly attached to the guidewire  30 . In this embodiment, the guidewire  30  is slidable within device  10 . The guidwire  30  can be retrieved before device  10  is retrieved. 
         [0058]    Bands  38 ,  40  may be formed from any suitable biocompatible metal or metal alloy. In some embodiments, the bands are formed from a radiopaque metal alloy or radiopaque element loaded polymers. Examples of metals and metal alloys include, but are not limited to, platinum and alloys thereof, gold, silver, tungsten, tantalum, iridium and combinations thereof. 
         [0059]    Examples of radiopaque element loaded polymers include, but are not limited to, iodized polycarbonate, barium and bismuth loaded polymers and combinations thereof. 
         [0060]    Examples of barium compounds include, for example, barium sulfate. 
         [0061]    Examples of bismuth compounds include, but are not limited to, bismuth trioxide, bismuth subcarbonate and bismuth oxychloride. 
         [0062]    These lists are intended for illustrative purposes only and not as a limitation on the scope of the present invention. Those of ordinary skill in the art will be aware of alternatives to those materials listed herein. 
         [0063]    Device  10  can be employed only during a medical procedure for embolic protection during the procedure, or it can be implanted for a period of time for longer term embolic protection. 
         [0064]    Band  38  at the proximal end of the device  10  can be configured and arranged for recapture and retrieval of the device  10  from a patient&#39;s body lumen. Examples include, but are not limited to loops, threaded champfer captures, detents or hooks. 
         [0065]    The retrieval wire may include the corresponding capture mechanism, for example, hooks, screws, springs or loops. 
         [0066]    Moreover, when one or both ends of the device are pulled, the openings in the device will close together more tightly and can trap emboli within the device. 
         [0067]      FIG. 10  is a partial side view of the proximal end of device  10  including a band  38  with a loop  42  connected thereto. Also shown in  FIG. 10  is the corresponding hook  44  which may be formed integrally with the retrieval wire  46  in the distal end thereof for recapturing device  10 . Alternatively, a hook may be attached to the distal end of a wire rather than formed integrally with the wire. 
         [0068]      FIG. 11  is a partial side view of the proximal end of device  10  including a band  38  having a threaded champfer capture  48  connected thereto. Also shown in  FIG. 11  is the corresponding screw  50  which may either be formed integrally with the retrieval wire  52  or otherwise connected thereto. 
         [0069]      FIG. 12  is a partial side view of the proximal end of device  10  including a band  38  having a detent  54  connected thereto. Also shown in  FIG. 12  is the corresponding spring  56  which can be formed integrally with the distal end of retrieval wire  58  or otherwise connected thereto. 
         [0070]      FIG. 13  is a side view of an alternative embodiment of a catheter delivery device  34  which may be employed herein. Catheter delivery device  34  includes a guidewire  30  slidably disposed within device  10  which is disposed in a sheath  36 . Catheter delivery device  34  further includes a device control wire or retrieving wire  60  and a proximal shaft  62  which is connected to sheath  36  and is a hollow tubular member. Device  10  is fixedly connected to device control wire  60  at band  38  such as by crimping band  38  onto device control wire  60 . Device control wire  60  thus remains with device  10  during the medical procedure and is then employed to remove device  10  once the procedure has been concluded. In this embodiment, device  10  is not implanted in the patient but is only employed for embolic protection and filtering during the medical procedure. 
         [0071]    Device  10  can be formed from a variety of materials and with a variety of configurations including, but not limited to, membranes, mesh, braids, weaves, roves, knits, interwinding helical fibers, interconnected serpentine bands, a closed cell stent-like structure and so forth, the material having openings therein that are configured to divert larger emboli and to collect smaller emboli therein. In a mesh pattern, for example, the openings are suitably about 100 microns to about 400 microns. 
         [0072]    The openings in the mesh are dynamic from an open device configuration to a closed device configuration. For example, as the device is expanded the openings may be up to about 300 microns and as the device is collapsed and closed, the openings may be as small as about 40 microns so as to capture and remove emboli from the body when the device is withdrawn. These sizes apply to patterns other than mesh as well. 
         [0073]    Alternatively, the openings can be smaller so as to divert emboli, for example, during a transcatheter aortic valve implantation (TAVI) procedure. 
         [0074]    In some embodiments, the device is formed from a self-expanding material such as a self expanding metal alloy or a self-expanding polymer. In one embodiment, the device is formed from nitinol. 
         [0075]    In one embodiment the device has an expanded diameter of about 8-10 mm and a total length of about 4-6 cm. 
         [0076]    Various alternative embodiments of device  10  can be employed herein. In one embodiment shown in  FIG. 14 , device  10  comprises a stepped structure wherein a larger radially expandable end  64  is configured for placement in the brachiocephalic artery and a smaller radially expandable end  66  is configured for placement in the left subclavian artery. Device  10  is shown disposed on a mandrel  11  used for forming device  10 . Device  10  can be heat set after formation on the mandrel. 
         [0077]    Typical heat set conditions for a device formed from nitinol, for example, may include temperatures in the range of about 490° C. to about 800° C. The time for heat set varies depending on mass, size of the device and fixturing. For a device formed from stainless steel, fixture forming the wire below annealing temperature, for example less than about 425° C. is desirable. Of course these conditions may be changed depending on the material employed for formation of the device. 
         [0078]      FIG. 15  is an alternative embodiment of device  10  wherein device  10  has a tapered structure with a larger radially expandable end  68  tapering to a smaller radially expandable end  70 .  FIG. 15A  illustrates device  10  disposed in the vasculature wherein end portion  68  is disposed and expanded in the brachiocephalic artery  20  and covers both the right subclavian artery  22  and the right carotid artery  24 . End portion  70  of device  10  is disposed and expanded in the left subclavian artery  28  and wherein the middle portion  72  of device  10  covers the left carotid artery  26 . Device  10  is closed at either end. Device  10  is shown disposed over a guidewire  30  having a flexible, spring coil at one end. This device is shown delivered via the right subclavian artery  22  but can also be delivered from the left subclavian artery  28  as well. 
         [0079]    The end portion  70  for expansion the left subclavian artery  28  suitably has an expanded diameter of about 12 mm while end portion  68  for expansion in the brachiocephalic artery  20  suitably has an expanded diameter of about 14 mm. Delivery diameters are about 1-2 mm for both ends (4-7 Fr, 0.035″-0.080″). 
         [0080]    In another embodiment illustrates in  FIGS. 16  (top down view) and  17  (side view), a self-expanding ring  74  such as a nitinol ring is placed in a stent-like tube to form the radially expandable middle portion  16 . End portions  12 ,  14  are radially expandable. 
         [0081]      FIG. 18  illustrates an alternative embodiment of a device  10  similar to that shown in  FIGS. 16 and 17  wherein the device  10  includes a self-expanding ring  74  having a membrane  76  connected to the frame  80  of the device  10 . Ends portions  12 ,  14  are radially expandable. Membrane  76  can be formed of any suitable biocompatible polymeric material. One example is a polyurethane membrane. 
         [0082]    The membrane  76  can be affixed to the device  10  using any suitable method including adhesive bonding using a biocompatible adhesive, or laser or fusion welding. 
         [0083]      FIG. 19  illustrates an alternative embodiment wherein the central portion  16  of the device  10  has a different pattern than end portions  12 ,  14 . The central portion  16  is independently expandable laterally or in the aorta plane axis covering the left and right carotid arteries wherein the pattern has an opening size of about 100 to 200 microns and functions to divert emboli from entering the carotid arteries. 
         [0084]    As shown in  FIG. 20 , device  10  may comprise a closed cell stent-like structure including both small and large elements resembling a honeycomb pattern. The pattern may be cut using any suitable method including laser cutting the pattern into a tubular stent perform as is known in the art. The large elements provide structure while the smaller elements function as a filter to block or deflect emboli. The stent-like structure of the device provides vessel wall apposition, vessel patency and protection from large emboli by diversion, e.g. about 200 microns to about 400 microns when fully expanded, while maintaining the blood flow therethrough. The central portion of the device may be comprised of a nitinol ring, for example, a 0.003-0.006 flat or round nitinol wire, along with a smaller emboli diverting material, for example, a polyurethane membrane having holes sizing of about 100 microns to about 200 microns. 
         [0085]      FIG. 21  illustrates an embodiment wherein the stent-like structure includes a membrane  84  on the inner surface of a frame  82 . Frame  82  can be formed from any suitable material including metals and metal alloys such as shape memory metal alloys. In one embodiment, the frame is formed from nitinol. 
         [0086]    Shape memory polymers may also be employed herein including thermoset and thermoplastic polymers. Examples include, but are not limited to, polyimides, polyether-ether-ketones (PEEK), elastomeric polyurethanes, covalently cross-liked polyurethanes, and so forth. 
         [0087]    Membrane  82  may be formed from any suitable porous polymeric material. Examples of suitable materials include, but are not limited to, thermoplastic polymers and thermoplastic elastomeric polymer materials such as polyurethanes, polyether-block-amides and nylons. In one embodiment, the membrane is formed from a polyurethane. 
         [0088]    The pores may be provided in the membrane using any suitable method. One example is to employ laser cutting. 
         [0089]    The device  10  can be made using a variety of methods. In one embodiment, device  10  is formed on a shaped mandrel having circular end portions  102 ,  104  and a flat middle portion  106  as shown in  FIG. 22 .  FIG. 23  is a top down view of mandrel  100 . 
         [0090]      FIGS. 24  (side perspective view) and  FIG. 25  (side view) represents device  10  being formed on mandrel  100 . In a specific embodiment, a nitinol stent is formed on the shaped mandrel  100  and then heat set for retention of the shape. 
         [0091]    In an alternative embodiment, a die, such as a heat shape die or cold work die is employed to flatten the middle portion of a tubular stent-like structure as shown in  FIG. 26 .  FIG. 27  is a top down view showing tube  108  after shaping with die  110  wherein the central portion  16  and radial end portions  12 ,  14  of device  10  are formed. 
         [0092]    The description provided herein is not to be limited in scope by the specific embodiments described which are intended as single illustrations of individual aspects of certain embodiments. The methods, compositions and devices described herein can comprise any feature described herein either alone or in combination with any other feature(s) described herein. Indeed, various modifications, in addition to those shown and described herein, will become apparent to those skilled in the art from the foregoing description and accompanying drawings using no more than routine experimentation. Such modifications and equivalents are intended to fall within the scope of the appended claims. 
         [0093]    All publications, patents and patent applications mentioned in this specification are herein incorporated by reference in their entirety into the specification to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. Citation or discussion of a reference herein shall not be construed as an admission that such is prior art.