Expandable implant devices for filtering blood flow from atrial appendages

Abstract

Implant devices for filtering blood flowing through the ostium of an atrial appendage have component structures one or more of which are expandable. Devices with component structures in their unexpanded state have a compact size suitable for intra-cutaneous delivery to an atrial appendage situs. The expandable component structures are expanded in situ to deploy the devices. A device may have sufficiently short axial length so that most or almost all of the device length may fit within the ostium region. An expandable component structure in the device may include a blood-permeable filter element. The device may be deployed so that this component structure covers the ostium so as to direct the blood flow to pass through the filter element. The filter elements used in the devices may have hole size distributions selected to filter out harmful-size emboli. The filter elements may be embedded in elastic material so that hole-size distributions remain substantially unaffected by expansion of the device structures. Anchors attached to a component structure engage tissue surrounding the device and maintain the devices in position. The anchors may include inflatable anchors which engage interior walls of the atrial appendage.

What is claimed is:  
     
         1 . A device for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 a membrane tube having at least a first closed end wherein said first closed end comprises a blood-permeable filter; and    an expandable structure disposed in said tube, said structure having a collapsed configuration and an expanded configuration,    wherein said device is insertable in said appendage while said expandable structure is in said collapsed configuration, and wherein when said expandable structure is in said expanded configuration said closed end covers the ostium of said atrial appendage and portions of said membrane tube are pressed outwards against the interior walls of said atrial appendage anchoring said device therein.    
     
     
         2 . The device of  claim 1  wherein said membrane tube has a substantially cylindrical shape.  
     
     
         3 . The device of  claim 1  wherein said membrane tube has a second closed end.  
     
     
         4 . The device of  claim 3  wherein said second closed end comprises a blood-permeable filter.  
     
     
         5 . The device of  claim 1  wherein said expandable structure is self-expanding.  
     
     
         6 . The device of  claim 1  wherein said expandable structure expands from said collapsed configuration to said expanded configuration by means of an inflatable balloon.  
     
     
         7 . The device of  claim 6  wherein said first closed end further comprises a self-sealing opening for withdrawing said inflatable balloon.  
     
     
         8 . The device of  claim 7  wherein said self-sealing opening comprises an elastic ring.  
     
     
         9 . The device of  claim 7  wherein said self-sealing opening comprises overlapping membrane flaps.  
     
     
         10 . The device of  claim 1  wherein said membrane tube comprises elastomeric material.  
     
     
         11 . The device of  claim 1  wherein said membrane tube comprises braided material.  
     
     
         12 . The device of  claim 1  wherein said membrane tube comprises woven material.  
     
     
         13 . A method for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 providing a device comprising a membrane tube having at least a first closed end wherein said first closed end comprises a blood-permeable filter;    inserting said device in said appendage;    positioning said closed end to cover said ostium; and    anchoring said device in said atrial appendage.    
     
     
         14 . The method of  claim 13  wherein said anchoring comprises pressing sides of said tube outward against the interior walls of said atrial appendage.  
     
     
         15 . The method of  claim 13  wherein said providing a device further comprises disposing an expandable structure in said membrane tube, wherein said inserting further comprises placing said device in said atrial appendage while said expandable structure is in a collapsed configuration, and wherein said positioning and said anchoring comprise expanding said expandable structure to an expanded configuration.  
     
     
         16 . The method of  claim 15  wherein said expanding comprises using an inflatable balloon.  
     
     
         17 . The method of  claim 16  further comprising deflating and withdrawing said balloon from said atrial appendage after said device is anchored in said atrial appendage.  
     
     
         18 . A device for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 a cover comprising: 
 a filter element having a predetermined size; and  
 an expandable membrane attached to said filter element; and  
   an expandable structure for deploying said cover,    wherein said expandable membrane stretches as said cover is deployed and allows said predetermined size to remain substantially unchanged.    
     
     
         19 . The device of  claim 18  wherein said filter element comprises holes substantially impervious to harmful-size emboli.  
     
     
         20 . The filter of  claim 18  wherein said filter element is made of material which is less elastic than said expandable membrane  
     
     
         21 . A method for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 providing a cover comprising an expandable membrane attached to a filter element having a predetermined size;    providing an expandable structure to deploy said cover across said ostium; and    positioning said cover across said ostium using said expandable structure,    wherein said positioning comprises stretching said expandable membrane such that said predetermined size is substantially unchanged.    
     
     
         22 . A device for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 an expandable structure for covering said ostium; and    anchors disposed on the outer periphery of said expandable, wherein expandable structure has an axial length less than about the combined lengths of said ostium and a neck region of said atrial appendage leading to said ostium, wherein said expandable structure comprises a blood-permeable filter, and wherein said anchors engage surrounding ostium wall tissue.    
     
     
         23 . The device of  claim 22  wherein said expandable structure is self-expanding.  
     
     
         24 . The device of  claim 22  wherein said expandable structure expands in response to externally-initiated means.  
     
     
         25 . The device of  claim 24  wherein said externally-initiated means comprises an inflatable balloon.  
     
     
         26 . The device of  claim 22  wherein said blood-permeable filter comprises holes that are substantially impervious to harmful-size emboli.  
     
     
         27 . A method for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 providing an expandable structure comprising a blood-permeable filter, said expandable structure having an axial length less than about the length of an ostium;    providing anchors attached to said expandable structure;    disposing said expandable structure within said ostium;    positioning said expandable structure to cover said ostium; and    expanding said expandable structure so that said anchors engage surrounding ostium wall tissue.    
     
     
         28 . The method of  claim 27  wherein said providing an expandable structure comprises providing a self-expanding structure.  
     
     
         29 . The method of  claim 27  wherein said providing an expandable structure further comprises providing externally-initiated means to expand said expandable structure, and wherein said expanding comprises initiating said means.  
     
     
         30 . The method of  claim 29  wherein said providing externally-initiated means comprises providing an inflatable balloon, and wherein said initiating comprises inflating said inflatable balloon.  
     
     
         31 . The method of  claim 30  further comprising deflating and withdrawing said inflatable balloon after said anchors engage surrounding ostium wall tissue.  
     
     
         32 . The method of  claim 27  wherein said positioning said expandable structure to cover said ostium comprises positioning said expandable structure to direct substantially all blood flow through said ostium to pass through said filter.  
     
     
         33 . A device for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 a first structure comprising a blood-permeable filter element; and    a second structure attached to said first structure, said rear structure comprising at least one inflatable anchor set,    wherein said first structure is deployed across said ostium, and wherein said inflatable anchor set when inflated engages interior wall tissue of said atrial appendage to secure said device in its deployed position.    
     
     
         34 . The device of  claim 33  wherein said second structure comprises an axial portion, wherein said at least one inflatable anchor set comprises anchors attached to said axial portion along a radial circumference thereof.  
     
     
         35 . The device of  claim 33  wherein said second structure comprises an axial portion, wherein said at least one inflatable anchor set comprises anchors attached to said axial portion along an axial length thereof.  
     
     
         36 . The device of  claim 33  wherein said first structure comprises an inflatable structure.  
     
     
         37 . The device of  claim 33  wherein said filter element comprises holes substantially impervious to harmful-size emboli.  
     
     
         38 . A method for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 providing a device comprising: 
 a first structure comprising a blood-permeable filter element; and  
 a second structure attached to said first structure, said second structure  
 comprising at least one inflatable anchor set;  
   positioning said first structure to cover said ostium;    disposing said second structure interior to said atrial appendage; and    inflating said anchor set expanding so that said anchors engage surrounding atrial appendage wall tissue.    
     
     
         39 . The method of  claim 38  wherein providing an implant device further comprises providing said first structure comprising an inflatable structure.  
     
     
         40 . A device for filtering blood flowing through the ostium of an atrial appendage, comprising: 
 an expandable structure comprising: 
 a first portion having a blood-permeable filter element; and  
 a second portion having a cylindrical shape; and  
   anchors disposed on at least part of the exterior surface of said second portion,    wherein when said device is deployed in about the vicinity of said ostium by expanding said expandable structure said first portion covers said ostium to direct said blood flow through said filter element and said anchors engage surrounding wall tissue.    
     
     
         41 . The device of  claim 40  wherein said filter element comprises holes substantially impervious to filter harmful-size emboli.  
     
     
         42 . The device of  claim 40  wherein said second portion further comprises a substantially constant diameter cylindrical structure.  
     
     
         43 . The device of  claim 40  wherein said second portion further comprises a flared-diameter cylindrical structure.  
     
     
         44 . The device of  claim 40  wherein said expandable structure is self-expanding.  
     
     
         45 . The device of  claim 40  wherein said expandable structure is balloon-expandable.  
     
     
         46 . The device of  claim 40  wherein said expandable structure has elastic deformation properties causing said expandable structure to recoil in size from its expanded size.  
     
     
         47 . The device of  claim 46  wherein said recoil in size causes said anchors that have engaged surrounding wall tissue to pull back and draw said walls closer to said device.  
     
     
         48 . A method for filtering blood flow through the ostium of an atrial appendage, comprising: 
 providing a device comprising: 
 an expandable structure, said expandable structure comprising:  
 a first portion having a blood-permeable filter element; and  
 a second portion having a cylindrical shape; and  
 anchors disposed on at least part of the exterior surface of said second portion; and  
   deploying said device in about the vicinity of said ostium wherein said deploying comprises:    positioning said first portion to cover said ostium; and    expanding said expandable structure so that said anchors engage surrounding wall tissue.    
     
     
         49 . The method of  claim 48  wherein said providing a device further comprises providing said expandable structure which recoils in size from its expanded size, and wherein said expanding further comprises expanding and recoiling said expandable structure so that said anchors engage surrounding wall tissue and pull back drawing said walls toward said device.