Patent Publication Number: US-2021161638-A1

Title: Embolic protection device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/487,392, filed Apr. 13, 2017, which is a continuation of U.S. patent application Ser. No. 14/175,042, filed on Feb. 7, 2014, now U.S. Pat. No. 10,016,267, which is a continuation of U.S. patent application Ser. No. 13/648,992, filed Oct. 10, 2012, now U.S. Pat. No. 8,728,114, which is a continuation of U.S. patent application Ser. No. 13/347,046, filed Jan. 10, 2012, now U.S. Pat. No. 8,308,754, which is a continuation of U.S. patent application Ser. No. 10/493,854, filed Apr. 27, 2004, now U.S. Pat. No. 8,114,114, which is a National Stage Application of PCT/US2003/26938, filed Aug. 27, 2003, which claims the benefit of U.S. Provisional Application No. 60/406,492, filed Aug. 27, 2002, the full disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to apparatus and methods for providing embolic protection to a patient&#39;s aortic arch vessels during cardiac surgery and interventional cardiology procedures. 
     Cerebral embolism is a known complication of cardiac surgery, cardiopulmonary bypass and catheter-based interventional cardiology and electrophysiology procedures. Embolic particles, which may include thrombus, atheroma and lipids, may become dislodged by surgical or catheter manipulations and enter the bloodstream, embolizing in the brain or other vital organs downstream. Cerebral embolism can lead to neuropsychological deficits, stroke and even death. Prevention of cerebral embolism would benefit patients and improve the outcome of these procedures. 
     Previous devices for preventing cerebral embolism are described in the following U.S. patents and patent applications, which are hereby incorporated by reference: U.S. Pat. No. 6,371,935 Aortic catheter with flow divider and methods for preventing cerebral embolization, U.S. Pat. No. 6,361,545 Perfusion filter catheter, U.S. Pat. No. 6,254,563 Perfusion shunt apparatus and method, U.S. Pat. No. 6,139,517 Perfusion shunt apparatus and method, U.S. Pat. No. 6,537,297 Methods of protecting a patient from embolization during surgery, U.S. Pat. No. 6,499,487 Implantable cerebral protection device and methods of use, U.S. Pat. No. 5,769,816 Cannula with associated filter, US20030100940A1 Implantable intraluminal protector device and method of using same for stabilizing atheromas. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention takes the form of apparatus and methods for providing embolic protection to a patient&#39;s aortic arch vessels during cardiac surgery and interventional cardiology and electrophysiology procedures. Embolic particles in the aortic blood flow are prevented from entering the aortic arch vessels and carotid arteries that lead to the brain. The apparatus and methods of the present invention can also be used for embolic protection of other organ systems, such as the renal system. 
     In one embodiment, a stent-like embolic protection device is constructed of a self-expanding tubular mesh that may be woven out of wires or fibers or formed from a tube or sheet. The embolic protection device is compressed to a small diameter and inserted into a delivery tube or catheter, which is introduced via a peripheral artery or an aortotomy and advanced into the aortic arch. Once in place, the delivery tube is withdrawn to allow the device to expand similar to a self-expanding stent. The mesh of the device covers the ostia of the arch vessels, allowing blood to enter, but preventing potential emboli from entering the aortic arch vessels and carotid arteries. The device conforms closely to the walls of the aorta so that it will not interfere with performing cardiac surgery or interventional cardiology procedures. The embolic protection device may be collapsed and withdrawn from the aorta after the procedure or it may be left in the aorta for long-term embolic protection. 
     In another embodiment, the embolic protection device may be made with a flat panel of fine mesh textile fabric that is supported on a wire frame or the like. The panel of fine mesh fabric is held in place over the aortic arch vessels by the wire frame to filter out potential emboli. Being made of fabric, the device is free to conform to the ostia of the arch vessels to allow more surface area for blood flow compared to a flat panel. The wire frame may be attached to a handle or cannula for insertion through an aortotomy or to a catheter for peripheral artery insertion. In addition, the wire frame may include one or more wire hoops or a stent-like tubular structure for supporting the embolic protection device within the aortic arch. 
     Additional features are described which may be used with either embodiment of the embolic protection device. An embolic protection device is described with waves or undulations to provide more surface area for filtering out potential emboli and to prevent inadvertent occlusion of the arch vessels. Another embolic protection device is described with two layers of mesh material to provide additional protection against embolization and to prevent inadvertent occlusion of the arch vessels. An embolic protection device is described with an inflatable toroidal balloon for supporting the filter mesh material within the aorta. The embolic protection device or a portion of it may be coated with an antithrombogenic coating to reduce the formation of clots that could become potential emboli. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a stent-like embolic protection device deployed within a patient&#39;s aortic arch for protecting the aortic arch vessels and carotid arteries from potential emboli. 
         FIG. 2  shows a stent-like embolic protection device with waves or undulations. 
         FIG. 3  shows a cut-away view of a stent-like embolic protection device with two layers of mesh material. 
         FIG. 4  shows an alternative embodiment of an embolic protection device. 
         FIG. 5  shows another alternative embodiment of an embolic protection device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a stent-like embolic protection device  10  deployed within a patient&#39;s aortic arch for protecting the aortic arch vessels and carotid arteries from potential emboli. The embolic protection device  10  is made of a resilient material, either a polymer or a metal (e.g. Nitinol) or a combination of materials. The device  10  may be woven out of wires or fibers to form a tubular mesh structure  12  or by slitting and expanding a tube or sheet. Alternatively, the device  10  may be constructed with a tubular mesh structure  12  made of a flexible textile mesh with one or more wire hoops or a stent-like tubular structure for supporting the tubular mesh structure  12  within the aortic arch. The device  10  is compressible to a small diameter for insertion into the aorta via peripheral artery access or through an aortotomy. The device  10  is preferably self-expanding and, when expanded, has a generally tubular shape that conforms to the diameter and curvature of the aortic arch. 
     The embolic protection device  10  is compressed to a small diameter and inserted into a delivery tube or catheter  14 . The delivery tube is introduced via a peripheral artery or an aortotomy and advanced into the aortic arch. Once in place, the delivery tube  14  is withdrawn to allow the device  10  to expand similar to a self-expanding stent. The mesh  12  of the device covers the ostia of the arch vessels, allowing blood to enter, but preventing potential emboli from entering the aortic arch vessels and carotid arteries. The device  10  conforms closely to the walls of the aorta so that it will not interfere with performing cardiac surgery or catheter-based interventional cardiology or electrophysiology procedures. 
     Alternatively, the embolic protection device  10  may be balloon-expandable. In this case, the embolic protection device  10  would be crimped or compressed onto an expandable balloon mounted on a catheter. The catheter is introduced into the aortic arch and the balloon is expanded to deploy the embolic protection device  10  in the aorta. Other volume expanding mechanisms, such as a mechanical expander, may be used in lieu of an expandable balloon. 
     After the procedure is completed, the embolic protection device  10  may be compressed and withdrawn from the aorta. Alternatively, the device  10  may be left in the aorta for long-term embolic protection. The device  10  may be compressed using one or more drawstrings  16  that encircle the device. The drawstrings  16  are pulled to compress the device and the device is withdrawn into the delivery tube  14  for removal. Alternatively, the embolic protection device  10  may be stretched longitudinal with the aid of a catheter, which will cause the diameter of the device to contract. Alternatively, the embolic protection device  10  may use a magnetic mechanism for compressing the device for removal. Multiple magnets  18  are arranged around the periphery of the device  10 . After the procedure is completed, a catheter  20  carrying one or more strong magnets  22  is inserted through the lumen of the device  10  to compress the device around the catheter for removal. 
       FIG. 2  shows a stent-like embolic protection device  24  with waves or undulations  26  in the tubular mesh structure  28 . The waves or undulations  26  in the embolic protection device  24  provide more surface area for filtering out potential emboli and prevents inadvertent occlusion of the arch vessels. This feature may be combined with any of the other embodiments and features of the invention described herein. 
       FIG. 3  shows a cut-away view of a stent-like embolic protection device  30  wherein the tubular mesh structure  32  is constructed with two layers of mesh material. The embolic protection device  30  preferably has an outer layer  34  of fine mesh material and an inner layer  36  of coarse mesh material. The outer layer  34  is shown cut away so that the inner layer  36  is visible. One or both layers of the device  30  may be self-expanding. For example, the outer layer  34  may be made of a fine mesh textile fabric, while the inner layer  36  is made with a self-expanding wire mesh structure. The two-layer structure provides additional protection against embolization and prevents the fine mesh of the outer layer  34  from becoming clogged with large emboli. Also, because blood can flow between the inner and outer layers of the device, all of the arch vessels will continue to receive blood flow even if the inner layer in front of one or more of the vessels becomes clogged. This feature may be combined with any of the other embodiments and features of the invention described herein. For example, one or both layers of the two-layer construction may be made with waves or undulations as described above in connection with  FIG. 2 . 
       FIG. 4  shows an alternative embodiment of an embolic protection device  40 . In this embodiment, the embolic protection device  40  may be made with a panel of fine mesh textile fabric  42  that is supported on a wire frame  44  or the like. The panel of fine mesh fabric  42  is held in place over the aortic arch vessels by the wire frame  44  to filter out potential emboli. Being made of fabric, the mesh panel  42  is free to conform to the ostia of the arch vessels to allow more surface area for blood flow compared to a totally flat panel. 
     The wire frame  44  may be attached to a handle or cannula  46  for insertion through an aortotomy or to a catheter  48  for peripheral artery insertion. Alternatively or in addition, the wire frame  44  may include one or more wire hoops  50  or a stent-like tubular structure for supporting the embolic protection device  40  within the aortic arch. This embodiment and/or its features may be combined with any of the other embodiments and features of the invention described herein. For example, the mesh panel  42  may be made with waves or undulations as described above in connection with  FIG. 2  and/or with a two-layer construction as described in connection with  FIG. 3 . As a further example, the handle, cannula  46  or catheter  48  for insertion of the embolic protection device  40  described in connection with  FIG. 4  may also be combined with any of the embolic protection devices described in connection with  FIGS. 1-3 and 5 . 
       FIG. 5  shows another alternative embodiment of an embolic protection device  52 . An inflatable toroidal balloon  54  supports the upstream end of a tubular mesh structure  56 . The toroidal balloon  54  is inflated and deflated through a catheter  58  having an inflation lumen and, optionally, a guidewire lumen. The tubular mesh structure  56  may be a self-expanding structure woven of wires or fibers or it may be a flexible textile mesh. Optionally, one or more wire hoops  60  or the like may be used to support the tubular mesh structure  56  within the patent&#39;s aorta. Alternatively, one or more additional inflatable toroidal balloons  54  may be used in place of the optional wire hoops  60  to support the tubular mesh structure  56 . The features of this embodiment may be combined with any of the other embodiments and features of the invention described herein. For example, one or more inflatable toroidal balloons  54  may be combined with the embolic protection devices described in connection with  FIGS. 1-3  for supporting a tubular mesh structure or panel of mesh material. 
     The entire embolic protection device or a portion of it may be coated with an antithrombogenic coating, for example a bonded heparin coating, to reduce the formation of clots that could become potential emboli. Alternatively or in addition, the embolic protection device or a portion of it may have a drug-eluting coating containing an anti-inflammatory or antistenosis agent. 
     The embolic protection device of the present invention can also be used for embolic protection of other organ systems. For example, an embolic protection device can be deployed in the patient&#39;s descending aorta for preventing embolic particles in the aortic blood flow from entering the renal arteries and embolizing in the patient&#39;s kidneys. 
     While the present invention has been described herein with respect to the exemplary embodiments and the best mode for practicing the invention, it will be apparent to one of ordinary skill in the art that many modifications, improvements and subcombinations of the various embodiments, adaptations and variations can be made to the invention without departing from the spirit and scope thereof.