US20070060946A1 - Embolic protection system - Google Patents

Abstract

An embolic protection filter system comprises a collapsible embolic protection filter62having a collapsed configuration for delivery of the filter, and a deployed configuration and a temporary lumen defining member60. The lumen defining member60is used for loading a filter-containing delivery catheter63onto a guidewire65. After loading, the member60can be removed by pulling on a tab61.

Description

• This is a continuation of application Ser. No. 10/379,434 filed Mar. 5, 2003, which claims benefit of Provisional Application No. 60/361,340 filed Mar. 5, 2002. The entire disclosures of the prior application, application Ser. No. 10/379,434 is considered part of the disclosure of the accompanying continuation application and is hereby incorporated by reference.
INTRODUCTION
• This invention relates to a transvascular embolic protection system for safely capturing and retaining embolic material released during an interventional procedure while maintaining blood flow.
• Embolic protection systems of this general type are described in our published international patent applications WO 01/80776 and WO 01/80777.
• There is an economical and clinical need to provide an embolic protection system which will be easy and convenient for a clinician to prepare for use, to deploy and to retrieve. In addition there is a need to provide such a system which is suitable for use with standard medical equipment and will facilitate a wide range of clinical procedures to be carried out.
• Statements of Invention
• According to the invention, there is provided an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• • the filter being movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for deployment in a vasculature;
  • the filter at least in the collapsed configuration having a guidewire lumen defined at least partially therethrough for passing the filter over a guidewire;
  • wherein the guidewire lumen is defined by a lumen-defining member which is movable or removable reactive to the filter.
• In one embodiment, the lumen-defining member is a substantially tubular member.
• In one embodiment, the tubular member has a slit extending the length thereof for removal of the member from a guidewire.
• In another embodiment, the lumen-defining member comprises a portion of a delivery system.
• Preferably the lumen-defining member comprises a pusher element of the delivery system, the pusher being movable from an extended lumen-defining configuration for loading of a filter to a retracted configuration for deployment of the filter.
• According to another aspect of the invention, there is provided an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• • the filter being movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for deployment in a vasculature in apposition with a vasculature wall;
  • in the outwardly extended configuration the filter exerting an outward radial force on a vasculature wall sufficient to retain the filter in position against substantial longitudinal movement.
• In one embodiment, the filter comprises a filter body and a filter support frame to support the filter body in the outwardly extended configuration in apposition with a vasculature wall, the filter support frame providing the outward radial force.
• In one embodiment, the filter comprises a low-friction outer layer.
• Preferably the outer layer is of a hydrophilic material.
• In one embodiment, the filter comprises an inflatable member to enhance the outward radial force.
• In another embodiment, the filter defines a guidewire lumen for passing the filter over a guidewire.
• In one embodiment, the filter comprises an anchor for fixing the filter to the vasculature in the deployed configuration.
• In another embodiment, the filter comprises a filter body and a filter support frame to support the filter body in the deployed configuration.
• In one embodiment, the support frame comprises the anchor.
• In one embodiment, the filter body comprises the anchor.
• In another embodiment, the anchor comprises a plurality of anchor elements.
• In one embodiment, the anchor elements are spaced-apart circumferentially around the filter when the filter is in the deployed configuration.
• In one embodiment, the support frame comprises at least one support hoop.
• In another embodiment, the support frame has a longitudinal aspect,
• In a further embodiment, the filter is self supported in a vasculature in the absence of a guidewire.
• According to another aspect of the invention, there is provided an embolic protection filter assembly for deployment in a vasculature, the assembly comprising:
• • a filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter; and
  • a receiver to guide a docking device into association with the filter.
• In one embodiment, the filter has a guidewire lumen for passing the filter over a guidewire, and the receiver is configured to guide a guidewire into the guidewire lumen.
• In one embodiment, the guidewire lumen extends only partially through the filter.
• In another embodiment, the receiver is configured to guide a coupling member towards the filter for coupling to the filter.
• In one embodiment, the receiver comprises a funnel.
• In another embodiment, the funnel is movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for guiding a docking device.
• In one embodiment, the funnel is biased towards the outwardly extended configuration.
• In another embodiment, the funnel comprises a funnel body and a funnel support to support the funnel body in the outwardly extended configuration.
• In one embodiment, the funnel body comprises a membrane.
• In a further embodiment, the funnel support comprises a plurality of pivotable fingers.
• Preferably the receiver comprises an approach channel.
• In one embodiment, the channel is provided by a lumen in a catheter.
• In another embodiment, the receiver is mounted to the filter.
• In one embodiment, the receiver is detachably mounted to the filter.
• In another embodiment, the receiver is separate from the filter.
• In a further embodiment, the receiver has means to space the receiver from the wall of a vasculature.
• Preferably the spacing means comprises an inflatable member to engage the wall of a vasculature.
• In one embodiment, the receiver is at least partially provided by a wall of the filter.
• In another embodiment, the receiver is at least partially provided by a wall of the filter at the inlet end of the filter.
• In a further embodiment, the receiver is at least partially provided by a wall of the filter at the outlet end of the filter.
• In one embodiment, the receiver extends proximally of the inlet end of the filter.
• In another embodiment, the receiver is located distally of the inlet end of the filter.
• In a further embodiment, the receiver is radially offset from the longitudinal axis of the filter.
• According to another aspect of the invention there is provided, an embolic protection system comprising:
• • an embolic protection filter assembly as claimed in any ofclaims21 to43; and
• a docking device which may be guided by the receiver into association with the filter.
• In one embodiment, the docking device comprises a guidewire.
• In one embodiment, the docking device comprises a coupling member.
• According to another aspect of the invention, there is provided an embolic protection filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• • the filter having a guidewire aperture for passing the filter over a guidewire; and
  • the filter comprising a seal to seal the guidewire aperture.
• Preferably the seal is self-closing.
• In one embodiment, the seal is located at a proximal end of the filter, and/or at a distal end of the filter.
• In one embodiment, the filter has a tubular member extending from the guidewire aperture to define a guidewire lumen through the tubular member.
• In another embodiment, the tubular member extends through at least part of the filter.
• In one embodiment, the tubular member is radially offset from the longitudinal axis of the filter.
• In one embodiment, the seal is an annular member around the guidewire aperture, the annular member being closable down to seal the guidewire aperture.
• Preferably the annular member is a tube.
• In one embodiment, the annular member comprises a soft membrane.
• In one embodiment, the annular member comprises two or more circumferentially overlapping flaps.
• According to a further aspect of the invention, there is provided a retrieval catheter for retrieving a medical device deployed in a vasculature, the catheter comprising:
• • an outer catheter body; and
  • an inner coupling member having means for coupling to a medical device deployed in a vasculature;
  • the catheter body being movable distally relative to the coupling member to retrieve a coupled medical device into the catheter body.
• In one embodiment, the coupling means comprises a male or female member on the coupling member for engagement with a corresponding female or male member on the medical device.
• In one embodiment, the male member is movable between a low-profile configuration and an outwardly protruding configuration.
• In one embodiment, the male member is biased towards the outwardly protruding configuration.
• In another embodiment the male member is of a resilient material.
• Preferably the coupling means is substantially arrow-head shaped.
• In one embodiment, the male member is in the form of a hook for hooking around a female member on the medical device.
• In one embodiment, the male member is in the form of a hook for hooking around a tether arm on the medical device.
• In one embodiment, the tether arm is at a proximal end of the medical device.
• In another embodiment, the tether arm is located within the medical device.
• In one embodiment, the coupling means comprises at least one female member on the coupling member for engagement with at least one male member on the medical device.
• In one embodiment, the female member is in the form of a loop for looping around a protruding male member on the medical device.
• In one embodiment, the coupling means comprises a pair of jaws on the coupling member, the jaws being movable between an outwardly protruding configuration and a low-profile configuration to grasp the medical device.
• In one embodiment, the retrieval catheter comprises an actuator to move the jaws to the outwardly protruding configuration.
• In another embodiment, the actuator is movable longitudinally relative to the jaws to move the jaws in a camming arrangement to the outwardly protruding configuration.
• In a further embodiment, the jaws are biased towards the low-profile configuration.
• In one embodiment, the catheter body is engageable with the jaws to move the jaws to the low-profile configuration.
• In another embodiment, the jaws are biased towards the outwardly protruding configuration.
• In a further embodiment, the coupling member is at least partially of a magnetic material for magnetic coupling to an oppositely charged magnetic portion of the medical device.
• In one embodiment, the retrieval catheter comprises means to axially elongate a deployed medical device to collapse the medical device to a low-profile configuration for retrieval into the catheter body.
• In one embodiment, the elongation means comprises a second coupling member movable relative to the first coupling member to collapse the medical device.
• In another embodiment, the second coupling member comprises a pusher member movable distally relative to first coupling member to engage a deployed medical device distally of the first coupling means and thereby collapse the medical device.
• In a further embodiment, the catheter body has a guidewire lumen extending partially therethrough for passing the catheter body over a guidewire in a rapid exchange manner.
• In one embodiment, the guidewire lumen is offset radially from the coupling member.
• According to one embodiment, there is provided a retrieval catheter for retrieving an embolic protection filter deployed in a vasculature.
• In another aspect of the invention there is provided an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• • the filter being movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for deployment in a vasculature;
  • the filter at least in the collapsed configuration having a guidewire lumen defined at least partially therethrough for passing the filter over a guidewire;
  • wherein the guidewire lumen is defined by a lumen-defining member which is spaced proximally of the distal end of the filter.
• In one embodiment, the guidewire lumen is defined by a tubular member.
• In another embodiment, the tubular member is mounted to the filter.
• Preferably the filter comprises a snare engaging feature.
• Preferably the snare engaging feature is radiopaque.
• In another aspect the invention provides a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • providing a collapsible embolic protection filter having a collapsed configuration for delivery of the filter, and a deployed configuration;
  • advancing a guidewire through a vasculature;
  • crossing a desired treatment location with the guidewire;
  • deploying the filter distal to the treatment location;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a retrieval device;
  • engaging the filter with the retrieval device independent of the guidewire; and
  • withdrawing the retrieval device and the filter from the vasculature.
• In one case, after crossing a treatment location with the guidewire the embolic protection device is introduced over the guidewire.
• In one case, the deployed filter is retained independent of the guidewire against substantial longitudinal movement.
• In another case, the filter applies a radial force to the vasculature to substantially prevent movement of the filter relative to the vasculature in the deployed configuration.
• In one case, the filter in the deployed configuration is anchored to the vasculature.
• In one case, the method comprises the step of releasing the filter from the vasculature before retrieving the filter.
• In another case, the filter is simultaneously released and retrieved by moving a retrieval catheter distally relative to the filter.
• In one case the filter is released prior to retrieving the filter.
• In one case, the method comprises the step of axially elongating the filter to release the filter.
• According to another aspect the method comprises the steps of:
• withdrawing the guidewire from the filter and/or the desired treatment location; and
• subsequently placing a guidewire in the filter.
• In one case, the same guidewire is placed in the filter.
• In another case, another guidewire is placed in the filter.
• In one case, the interventional device is introduced over the guidewire for carrying out the interventional procedure.
• In one case, the interventional procedure comprises a stenting of the treatment location.
• In another case, the interventional procedure comprises a balloon angioplasty procedure at the treatment location.
• According to another aspect the invention provides a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • advancing a guidewire through a vasculature;
  • crossing a desired treatment location with the guidewire;
  • introducing over the guidewire a collapsible embolic protection filter having a collapsed configuration for delivery of the filter, and a deployed configuration;
  • deploying the filter distal to the treatment location;
  • the filter in the deployed configuration being retained in apposition with the vasculature independent of the guidewire against substantial longitudinal movement;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a retrieval device;
  • engaging the filter with the retrieval device; and
  • withdrawing the retrieval device and the filter from the vasculature.
• In one case, on the filter applies a radial force to the vasculature to substantially prevent movement of the filter relative to the vasculature in the deployed configuration.
• Preferably the filter in the deployed configuration is anchored to the vasculature.
• In one case, the filter is engaged with the retrieval device independent of the guidewire.
• According to another aspect the method comprises the step of releasing the filter from the vasculature before retrieving the filter.
• According to a further aspect, the retrieval device is a retrieval catheter and the filter is simultaneously released and retrieved by moving the retrieval catheter distally relative to the filter.
• In one case, the filter is released prior to retrieving the filter.
• According to one aspect, the method comprises the step of axially elongating the filter to release of the filter.
• Preferably the method comprises the steps of:
• • withdrawing the guidewire from the filter and the desired treatment location; and
  • subsequently placing a guidewire in the filter.
• According to a one aspect, the same guidewire is placed in the filter.
• According to a another aspect, another guidewire is placed in the filter.
• In one case, the interventional device is introduced over the guidewire for carrying out the interventional procedure.
• Preferably the interventional procedure comprises a stenting of the treatment location.
• According to one aspect, the interventional procedure comprises a balloon angioplasty procedure at the treatment location.
• According to a further aspect a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • providing a collapsible embolic protection filter having a collapsed configuration for delivery of the filter, and a deployed configuration;
  • advancing a guidewire through a vasculature;
  • crossing a desired treatment location with the guidewire;
  • deploying the filter distal to the treatment location;
  • withdrawing the guidewire from the filter and/or the desired treatment location; and
  • subsequently placing a guidewire in the filter;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a retrieval device;
  • engaging the filter with the retrieval device; and
  • withdrawing the retrieval device and the filter from the vasculature.
• In one case, the same guidewire is placed in the filter.
• In another case, another guidewire is placed in the filter.
• In one case the interventional device is introduced over the guidewire for carrying out the interventional procedure.
• In another case, the interventional procedure comprises a stenting of the treatment location.
• In one case, the interventional procedure comprises a balloon angioplasty procedure at the treatment location.
• In one case, the filter is engaged with the retrieval device independent of the guidewire.
• In another case, after crossing a treatment location with the guidewire the embolic protection device is introduced over the guidewire.
• Preferably the deployed filter is retained independent of the guidewire against substantial longitudinal movement.
• In one case, on deployment, the filter applies a radial force to the vasculature to substantially prevent movement of the filter relative to the vasculature in the deployed configuration.
• In one case, the filter in the deployed configuration is anchored to the vasculature.
• In one case, the method comprises the step of releasing the filter from the vasculature before retrieving the filter.
• In another case, the filter is simultaneously released and retrieved by moving a retrieval catheter distally relative to the filter.
• In another case, the filter is released prior to retrieving the filter.
• According to one aspect, the method comprises the step of axially elongating the filter to release the filter.
• According to a further aspect the invention provides a method of retrieving a medical device from a vasculature, the method comprising the steps of:
• • advancing a retrieval catheter through a vasculature until a distal end of the retrieval catheter is proximally of the deployed medical device;
  • axially elongating an element of the medical device to collapse the medical device; and
  • moving the retrieval catheter distally relative to the collapsed medical device to retrieve the medical device into the retrieval catheter.
• In one case, the method comprises the steps of:
• engaging a first coupling member with the element of the deployed medical device;
• engaging a second coupling member with the element of the deployed medical device; and
• moving the coupling members relative to one another to axially elongate the element of the medical device.
• According to another aspect of the invention, there is provided an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• • the filter being movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for deployment in a vasculature;
  • the filter at least in the collapsed configuration having a guidewire lumen defined at least partially therethrough for passing the filter over a guidewire;
  • wherein the tubular member is shortenable upon movement of the filter from the collapsed configuration to the extended configuration.
• In one embodiment, the tubular member comprises at least two telescopable tubes.
• According to another aspect of the invention, there is provided an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• • the filter being movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for deployment in a vasculature;
  • the filter at least in the collapsed configuration having a guidewire lumen defined at least partially therethrough for passing the filter over a guidewire; wherein the filter comprises a support structure, in the collapsed configuration the support structure forming a tubular member to define the guidewire lumen.
• According to another aspect the invention provides a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • advancing a guidewire through a vasculature;
  • crossing a desired treatment location with the guidewire;
  • introducing over the guidewire a collapsible embolic protection filter having a collapsed configuration for delivery and withdrawal of the filter, and a deployed configuration;
  • deploying the filter distal to the treatment location;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a retrieval catheter;
  • fixing an abutment to the guidewire;
  • engaging the guidewire abutment with the filter to prevent movement of the filter distally of the guidewire abutment;
  • collapsing the filter and retrieving the filter into the retrieval catheter and with it the captured embolic material; and
  • withdrawing the retrieval catheter and the collapsed filter from the vasculature.
• In one case, the abutment is fixed to the guidewire during deployment of the filter.
• In another case, the abutment is fixed to the guidewire before advancing the guidewire through the vasculature.
• According to another aspect of the invention there is provided a retrieval catheter for retrieving a medical device deployed in a vasculature, the catheter comprising:
• • a first coupling member having means for coupling to a medical device deployed in a vasculature; and
  • a second coupling member having means for coupling to the deployed medical device;
  • the coupling members being relatively movable to axially elongate the medical device and collapse the medical device.
• In one embodiment, the catheter comprises an outer catheter body movable distally relative to the coupling members to retrieve a collapsed medical device into the catheter body.
• According to another aspect of the invention, there is provided an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter; and
• • the filter comprising an inflatable member to exert an outward radial force on a vasculature wall sufficient to retain the filter in position against substantial longitudinal movement.
• According to a further aspect of the invention there is provided an embolic protection filter system comprising:
• a collapsible embolic protection filter having a collapsed configuration for delivery of the filter, and a deployed configuration; and
• a snare for engaging the filter.
• In one embodiment, the filter has a snare engaging feature for engagement by the snare.
• In one embodiment, the filter comprises a support frame and the snare engaging feature is provided by or on the support frame.
• Preferably the snare is radiopaque at least in a region of engagement with a filter.
• In one embodiment, the snare engaging feature is radiopaque.
• In another embodiment, the snare comprises a snaring hoop.
• According to a further aspect the invention provides a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • providing a collapsible embolic protection filter having a collapsed configuration for delivery of the filter, and a deployed configuration;
  • advancing a guidewire through a vasculature;
  • crossing a desired treatment location with the guidewire;
  • deploying the filter distal to the treatment location;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a snare;
  • engaging the snare with the filter; and
  • withdrawing the snare and the filter.
• In one case, the filter has a snare engaging feature and the snare is engaged with the snare engaging feature.
• In another case, the snare engaging feature is provided on or by a support frame of the filter.
• In one case, the method comprises the steps of leading the snare into engagement with the snare engaging feature of the filter and monitoring the engagement of the filter with the snare.
• In one case, the snare and/or snare engaging features are radiopaque for external monitoring of the engagement.
• In one case, the snare is engaged with the filter independent of the guidewire.
• In another case, after crossing a treatment location with the guidewire the embolic protection device is introduced over the guidewire.
• According to the invention, there is provided a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • advancing a guidewire through a vasculature;
  • crossing a desired treatment location with the guidewire;
  • introducing over the guidewire a collapsible embolic protection filter having a collapsed configuration for delivery and withdrawal of the filter, and a deployed configuration;
  • deploying the filter distal to the treatment location;
  • the filter in the deployed configuration being in apposition with the vasculature so that the filter is retained in position against substantial longitudinal movement, on deployment in the vasculature;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a retrieval catheter;
  • collapsing the filter and retrieving the filter at least partially into the retrieval catheter and with it the captured embolic material; and
  • withdrawing the retrieval catheter and the collapsed filter from the vasculature.
• In one embodiment of the invention the method comprises the step of releasing the apposition of the filter with the vasculature before collapsing the filter.
• The filter may be simultaneously collapsed and retrieved into the retrieval catheter by moving the retrieval catheter distally relative to the filter.
• Alternatively the filter may be collapsed prior to retrieving the filter into the retrieval catheter. Preferably the method comprises the step of axially elongating the filter to collapse the filter.
• Desirably the method comprises the step of engaging a part of the retrieval catheter with the filter to aid collapsing of the filter.
• In one case the method comprises the steps of:
• • withdrawing the guidewire from the filter and the desired treatment location; and
  • crossing the desired treatment location with another guidewire.
• The interventional device may be introduced over the other guidewire for carrying out the interventional procedure.
• In one case the interventional procedure comprises a stenting of the treatment location. In another case the interventional procedure comprises a balloon angioplasty procedure at the treatment location.
• In another aspect the invention provides a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • advancing a guidewire through a vasculature;
  • crossing a desired treatment location with the guidewire;
  • introducing over the guidewire a collapsible embolic protection filter having a collapsed configuration for delivery and withdrawal at the filter, and a deployed configuration;
  • deploying the filter distal to the treatment location;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a retrieval catheter;
  • fixing an abutment to the guidewire;
  • engaging the guidewire abutment with the filter to prevent movement of the filter distally of the guidewire abutment;
  • collapsing the filter and retrieving the filter into the retrieval catheter and with it the captured embolic material; and
  • withdrawing the retrieval catheter and the collapsed filter from the vasculature.
• The abutment may be fixed to the guidewire during deployment of the filter. Alternatively the abutment may be fixed to the guidewire before advancing the guidewire through the vasculature.
• In a further aspect of the invention, there is provided a retrieval catheter for retrieving a medical device deployed in a vasculature, the catheter comprising:
• • an outer catheter body; and
  • an inner coupling member having means for coupling to a medical device deployed in a vasculature;
  • the catheter body being movable distally relative to the coupling member to retrieve a coupled medical device into the catheter body.
• In one embodiment of the invention the coupling means comprises a male or female member on the coupling member for engagement with a corresponding female or male member on the medical device.
• In a preferred case the male member is movable between a low-profile configuration and an outwardly protruding configuration. Ideally the male member is biased towards the outwardly protruding configuration. Most preferably the male member is of a resilient material.
• In one case the coupling means is substantially arrow-head shaped.
• In another case the male member is in the form of a hook for hooking around a female member on the medical device. Alternatively the male member may be in the form of a hook for hooking around a tether arm on the medical device. Ideally the tether arm is at a proximal end of the medical device. The tether arm may be located within the medical device.
• In another embodiment of the invention the coupling means comprises at least one female member on the coupling member for engagement with at least one male member on the medical device. The female member may be in the form of a loop for looping around a protruding male member on the medical device.
• In a preferred embodiment the coupling means comprises a pair of jaws on the coupling member, the jaws being movable between an outwardly protruding configuration and a low-profile configuration to grasp the medical device. The retrieval catheter may comprise an actuator to move the jaws to the outwardly protruding configuration. Ideally the actuator is movable longitudinally relative to the jaws to move the jaws in a camming arrangement to the outwardly protruding configuration. Most preferably the jaws are biased towards the low-profile configuration.
• In another embodiment the catheter body is engageable with the jaws to move the jaws to the low-profile configuration. The jaws may be biased towards the outwardly protruding configuration.
• In another embodiment of the invention the coupling means comprises an inflatable member on the coupling member for engagement with the medical device. Preferably the inflatable member is movable inwardly upon inflation to engage the medical device. The coupling means may comprise an engagement surface on the coupling member for engagement with an inflatable member on the medical device.
• In a further embodiment the coupling member is at least partially of a magnetic material for magnetic coupling to an oppositely charged magnetic portion of the medical device.
• The retrieval catheter may comprise means to axially elongate a deployed medical device to collapse the medical device to a low-profile configuration for retrieval into the catheter body. Preferably the elongation means comprises a second coupling member movable relative to the first coupling member to collapse the medical device. Ideally the second coupling member comprises a pusher member movable distally relative to first coupling member to engage a deployed medical device distally of the first coupling means and thereby collapse the medical device.
• In one case the catheter body has a guidewire lumen extending partially therethrough for passing the catheter body over a guidewire in a rapid exchange manner. The guidewire lumen may be offset radially from the coupling member.
• The retrieval catheter of the invention may be for retrieving an embolic protection filter deployed in a vasculature.
• According to another aspect of the invention, there is provided a retrieval catheter for retrieving a medical device deployed in a vasculature, the catheter comprising:
• • a first coupling member having means for coupling to a medical device deployed in a vasculature; and
  • a second coupling member having means for coupling to the deployed medical device;
  • the coupling members being relatively movable to axially elongate the medical device and collapse the medical device.
• In one embodiment the catheter comprises an outer catheter body movable distally relative to the coupling members to retrieve a collapsed medical device into the catheter body.
• In another aspect, the invention provides a method of retrieving a medical device from a vasculature, the method comprising the steps of:
• • advancing a retrieval catheter through a vasculature until a distal end of the retrieval catheter is proximally of the deployed medical device;
  • axially elongating an element of the medical device to collapse the medical device; and
  • moving the retrieval catheter distally relative to the collapsed medical device to retrieve the medical device into the retrieval catheter.
• In one embodiment the method comprises the steps of:
• • engaging a first coupling member with the element of the deployed medical device;
  • engaging a second coupling member with the element of the deployed medical device; and
  • moving the coupling members relative to one another to axially elongate the element of the medical device.
• The invention also provides in another aspect an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• the filter being movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for deployment in a vasculature in apposition with a vasculature wall;
• in the outwardly extended configuration the filter exerting an outward radial force on a vasculature wall sufficient to retain the filter in position against substantial longitudinal movement.
• In one embodiment of the invention the filter comprises a filter body and a filter support frame to support the filter body in the outwardly extended configuration in apposition with a vasculature wall, the filter support frame providing the outward radial force.
• The filter may comprise a low-friction outer layer. Preferably the outer layer is of a hydrophilic material.
• In one case the filter comprises an inflatable member to enhance the outward radial force.
• Ideally the filter defines a guidewire lumen for passing the filter over a guidewire.
• According to another aspect of the invention, there is provided an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter; and
• the filter comprising a central tether extending proximally of the filter.
• Ideally the tether is a generally central tether.
• The tether may comprise a wire, preferably the wire is configured to facilitate passage of a medical device over the wire.
• The invention also provides in a further aspect, an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter; and
• the filter comprising an inflatable member to exert an outward radial force on a vasculature wall sufficient to retain the filter in position against substantial longitudinal movement.
• In another aspect, the invention provides a method for the capture and removal of embolic material from a vasculature during an interventional procedure comprising the steps of:
• • advancing a first guidewire through a vasculature;
  • crossing a desired treatment location with the first guidewire,
  • introducing over the first guidewire a collapsible embolic protection filter having a collapsed configuration for delivery and withdrawal of the filter, and a deployed configuration;
  • deploying the filter distal to the treatment location;
  • withdrawing the first guidewire from the filter and the desired treatment location;
  • crossing the desired treatment location with a second guidewire;
  • introducing over the second guidewire an interventional device;
  • carrying out an interventional procedure at the treatment location, embolic material generated during the treatment procedure being captured by the deployed filter;
  • advancing a retrieval catheter;
  • collapsing the filter and retrieving the filter into the retrieval catheter and with it the captured embolic material; and
  • withdrawing the retrieval catheter and the collapsed filter from the vasculature.
• In one embodiment of the invention the method comprises the step of leading the second guidewire through the filter prior to carrying out the interventional procedure. The method may comprise the step of guiding the second guidewire through the filter. Ideally the second guidewire remains proximal of the deployed filter.
• In another embodiment the method comprises the steps of:
• • withdrawing the second guidewire from the filter and the desired treatment location;
  • advancing a third guidewire to the filter; and
  • advancing the retrieval catheter over the third guidewire.
• In one case collapsing the filter into the retrieval catheter comprises the step of releasing the filter from apposition with the vasculature wall.
• The diameters of the guidewires may differ. The material properties of the guidewires may differ.
• The invention provides in a further aspect an embolic protection filter assembly for deployment in a vasculature, the assembly comprising:
• • a filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter; and
  • a receiver to guide a docking device into association with the filter.
• In one embodiment the filter has a guidewire lumen for passing the filter over a guidewire, and the receiver is configured to guide a guidewire into the guidewire lumen. The guidewire lumen may extend only partially through the filter.
• Preferably the receiver is configured to guide a coupling member towards the filter for coupling to the filter.
• In one case the receiver comprises a funnel. Preferably the funnel is movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for guiding a docking device. Ideally the funnel is biased towards the outwardly extended configuration.
• In one embodiment the funnel comprises a funnel body and a funnel support to support the funnel body in the outwardly extended configuration. Preferably the funnel body comprises a membrane. Ideally the funnel support comprises a plurality of pivotable fingers.
• In another embodiment the receiver comprises an approach channel. Preferably the channel is provided by a lumen in a catheter.
• The receiver may be mounted to the filter. Preferably the receiver is detachably mounted to the filter.
• Alternatively the receiver may be separate from the filter.
• In a preferred embodiment the receiver has means to space the receiver from the wall of a vasculature. Ideally the spacing means comprises an inflatable member to engage the wall of a vasculature.
• In one embodiment the receiver is at least partially provided by a wall of the filter. Preferably the receiver is at least partially provided by a wall of the filter at the inlet end of the filter. Alternatively the receiver may be at least partially provided by a wall of the filter at the outlet end of the filter.
• In one case the receiver extends proximally of the inlet end of the filter. In another case the receiver is located distally of the inlet end of the filter.
• In a further embodiment the receiver is radially offset from the longitudinal axis of the filter.
• According to a further aspect of the invention, there is provided an embolic protection system comprising:
• • an embolic protection filter assembly of the invention; and
  • a docking device which may be guided by the receiver into association with the filter.
• In one embodiment the docking device comprises a guidewire.
• In another case the docking device comprises a coupling member.
• In another aspect, the invention provides an embolic protection filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;
• the filter having a guidewire aperture for passing the filter over a guidewire; and
• the filter comprising a seal to seal the guidewire aperture.
• The seal may be self-closing.
• Ideally the seal is located at a proximal end of the filter, and/or at a distal end of the filter.
• The filter may have a tubular member extending from the guidewire aperture to define a guidewire lumen through the tubular member. In one case the tubular member extends through at least part of the filter. Preferably the tubular member is radially offset from the longitudinal axis of the filter.
• In one embodiment the seal is an annular member around the guidewire aperture, the annular member being closable down to seat the guidewire aperture. In one case the annular member is a tube. In another case the annular member comprises a soft membrane. The annular member may comprise two or more circumferentially overlapping flaps.
• The invention provides in another aspect an embolic protection filter for deployment in a vasculature, the filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter; the filter being movable between a collapsed configuration for movement through a vasculature, and an outwardly extended configuration for deployment in a vasculature;
• the filter at least in the collapsed configuration having a guidewire lumen defined at least partially therethrough for passing the filter over a guidewire.
• The guidewire lumen may be defined by a tubular member extending at least partially through the filter.
• In one case the tubular member is mounted to the filter. In another case the tubular member is spaced proximally of a distal end of the filter.
• Preferably the tubular member is shortenable upon movement of the filter from the collapsed configuration to the extended configuration. Ideally the tubular member comprises at least two telescopable tubes.
• In one embodiment the tubular member is provided by a catheter.
• The catheter may be a retrieval catheter, or a delivery catheter.
• In another embodiment of the invention the filter comprises a support structure, in the collapsed configuration the support structure forming a tubular member to define the guidewire lumen.
BRIEF DESCRIPTION OF DRAWINGS
• The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:
• FIG. 1 is a perspective of an embolic protection filter according to the invention;
• FIGS.2 to16 are partially cross-sectional, side views illustrating the use of an embolic protection filter;
• FIG. 17 is a perspective view of another filter of the invention;
• FIG. 18 is a side view of a further filter of the invention;
• FIG. 19 is an end view of the filter ofFIG. 18;
• FIG. 20 is a side view of another filter of the invention;
• FIGS. 21 and 22 are side views of another filter, in use;
• FIGS.23 to26 are diagrams illustrating a filter of the invention, in use;
• FIGS.27 to31 are perspective views of various alternative constructions of filters;
• FIGS.32 to39 are various views of a delivery catheter which may be used in the invention;
• FIGS.40 to54 are side, partially cross sectional views illustrating various steps in the method of the invention;
• FIGS.55 to57 are various views of another delivery catheter which may be used in the invention;
• FIGS.58 to61 are views illustrating the use of a temporary lumen-defining member for filter delivery;
• FIGS.62 to68 are views illustrating the use of a part of the delivery system to provide a temporary lumen-defining member;
• FIGS. 69 and 70 are perspective views of such a lumen-defining member extending to a side of a filter;
• FIGS. 71 and 72 are perspective views of such a lumen-defining member extending through a filter;
• FIG. 73 is a schematic view of another embolic protection filter according to the invention in a deployed configuration;
• FIG. 74 is a schematic view of the filter ofFIG. 73 collapsed in a delivery catheter;
• FIG. 75 is a perspective view of another embolic protection filter according to the invention;
• FIG. 76 is a cross-sectional, side view of a delivery catheter according to the invention in a delivery configuration;
• FIG. 77 is a cross-sectional, side view of the filter ofFIG. 75 collapsed in the delivery catheter ofFIG. 87;
• FIG. 78 is a cross-sectional, side view of the delivery catheter ofFIG. 76 in a deployment configuration;
• FIGS. 79 and 80 are views of a filter with a guidewire passageway at the side thereof;
• FIG. 81 is an enlarged view of a detail ofFIG. 80;
• FIGS.82 to84 are perspective views illustrating different guidewire paths;
• FIG. 85 is a perspective view of another embolic protection filter according to the invention;
• FIG. 86 is an enlarged, perspective view of a receiver of the embolic protection filter ofFIG. 85;
• FIGS.87 to89 are partially cross-sectional, side views illustrating guiding of a guidewire through the embolic protection filter ofFIG. 85;
• FIG. 90 is a partially cross-sectional, side view of the embolic protection filter ofFIG. 85 deployed in a vasculature;
• FIGS. 91 and 92 are enlarged, perspective views of seals of the embolic protection filter ofFIG. 90;
• FIGS.93 to110 are partially cross-sectional, side views of the embolic protection filter ofFIG. 85 in use;
• FIG. 111 is a side view of another retrieval catheter according to the invention passing over a guidewire,
• FIG. 112 is a view along line B-B inFIG. 111;
• FIGS. 113 and 114 are partially cross-sectional, side views illustrating retrieval of the filter ofFIG. 1 using the retrieval catheter ofFIG. 51(a);
• FIG. 115 is a perspective view of another embolic protection filter according to the invention;
• FIGS. 116 and 117 are perspective and cross-sectional, side views respectively of another embolic protection filter according to the invention;
• FIG. 118 is a perspective view of a further embolic protection filter according to the invention guiding a guidewire through the embolic protection filter;
• FIGS. 119 and 120 are partially cross-sectional, side views of the embolic protection filter ofFIG. 118 guiding a guidewire through the embolic protection filter;
• FIG. 121 is an end view of the embolic protection filter ofFIG. 118;
• FIG. 122 is a side view of a distal end of a filter;
• FIGS.123 to126 are end views in the direction of the arrow X ofFIG. 122 of various outlet seals;
• FIG. 127 is a perspective view of the filter of FIGS.122 to126, in use;
• FIGS.128 to132 are various views of a filter with an alternative outlet seal;
• FIG. 133 is a perspective view of an alternative outlet seal;
• FIGS. 134 and 135 are cross-sectional views of the seal ofFIG. 133, in use,
• FIGS. 136 and 137 are perspective views of further outlet seals;
• FIG. 138 is a perspective view of a further outlet seal;
• FIGS. 139 and 140 are cross-sectional views on the line A-A ofFIG. 138 in different configurations of use;
• FIGS.141 to143 are views of a further outlet seal arrangement;
• FIGS.144 to149 are partially cross-sectional side views illustrating retrieval of an embolic protection device;
• FIGS.150 to163 are partially cross-sectional, side views of an embolic protection filter and a retrieval catheter in use;
• FIGS.164 to165 are partially cross-sectional, side views illustrating retrieval of another embolic protection filter according to the invention;
• FIGS. 166 and 167 are schematic side views illustrating retrieval of an embolic protection filter using other retrieval catheters according to the invention;
• FIG. 168 is a perspective view of another embolic protection filter according to the invention;
• FIG. 169 is a perspective view illustrating retrieval of the filter ofFIG. 168;
• FIG. 170 is a perspective view of another embolic protection filter according to the invention;
• FIG. 171 is a perspective view illustrating retrieval of the filter ofFIG. 170,
• FIGS. 172 and 173 are perspective views of further embolic protection filters according to the invention;
• FIGS.174 to178 are schematic views illustrating retrieval of the embolic protection filter ofFIG. 168;
• FIGS. 179 and 180 are perspective views of further embolic protection filters according to the invention;
• FIGS. 181 and 182 are perspective views illustrating retrieval of another embolic protection filter according to the invention;
• FIG. 183 is a perspective view of another embolic protection filter deployed in a vasculature;
• FIG. 184 is a side view of part of another retrieval catheter according to the invention;
• FIG. 185 is a cross-sectional, side view of the retrieval catheter ofFIG. 184;
• FIGS.186 to188 are schematic side views illustrating retrieval of an embolic protection filter using the retrieval catheter ofFIG. 184;
• FIG. 189 is a side view along line A-A inFIG. 188;
• FIGS.190 to192 are cross-sectional side views illustrating retrieval of an embolic protection filter using another retrieval catheter of the invention;
• FIG. 193 is a cross-sectional, side view of part of another retrieval catheter according to the invention;
• FIG. 194 is a partially cross-sectional, side view illustrating collapse of an embolic protection filter using the retrieval catheter ofFIG. 193;
• FIGS.195 to201 are various views illustrating the snaring of an embolic protection device of the invention;
• FIGS.201 to206 are various views illustrating snaring of another filter;
• FIGS.207 to212 are various views illustrating snaring of a further filter;
• FIGS.213 to218 are views illustrating another retrieval system;
• FIGS.219 to234 are views of the snaring of a filter of the invention;
• FIGS. 225 and 226 are views of another filter of the invention;
• FIGS.227 to230 illustrate retrieval of filters;
• FIGS. 231 and 232 illustrate snaring of another filter;
• FIGS.233 to237 are side, partially cross-sectional views of the snaring of any filter;
• FIGS. 238 and 239 illustrate the snaring of another filter;
• FIG. 240 is a partially cross-sectional, side view of an embolic protection filter according to the invention in an expanded configuration;
• FIG. 241 is a partially cross-sectional, side view of the filter ofFIG. 240 in a collapsed configuration;
• FIGS. 242 and 243 are partially cross-sectional, side views illustrating retrieval of the filter ofFIG. 240;
• FIG. 244 is a partially cross-sectional, side view of the filter ofFIG. 240 after being recrossed with a guidewire;
• FIGS. 245 and 246 are partially cross-sectional, side views illustrating retrieval of the filter ofFIG. 244.
• FIGS.247 to251 are views similar toFIGS. 90, 91, and94 to96 respectively of another embolic protection filter according to the invention;
• FIG. 252 is a schematic view illustrating fixing of an abutment to a guidewire;
• [253 to255 are not used]
• FIG. 256 is a schematic view of the guidewire and the abutment;
• FIG. 257 is a perspective view of another embolic protection filter according to the invention passing over a guidewire;
• FIGS.258 to260 are partially cross-sectional side views illustrating guiding of a guidewire through an embolic protection filter;
• FIG. 261 is a cross-sectional, end view of a catheter according to the invention;
• FIG. 262 is a cross-sectional, end view of a catheter according to the invention;
• FIG. 263 is a cross-sectional, side view of another retrieval catheter according to the invention; and
• FIG. 264 is a partially cross-sectional, side view illustrating retrieval of an embolic protection filter using the retrieval catheter ofFIG. 263.
Detailed Description
• The invention provides an embolic protection system which has a number of features which allows the system to be used in placing a guide catheter proximal to lesion as per standard practice and advance any suitable guidewire across the lesion. A load filter is loaded into the delivery catheter in such a way as to provide a lumen through the loaded device through which the guidewire will pass. The loaded device is advanced over the guidewire and across the lesion. The filter is deployed from the delivery catheter and the delivery catheter is removed. The filter remains stable in the vessel without any user control. Standard interventional procedures (angioplasty, stent etc . . .) can be performed. The guidewire may be replaced by simply removing the initial wire and advancing a replacement wire through the guide catheter, across the lesion and through the filter. The filter may be retrieved by advancing a retrieval catheter over the guidewire and up to the filter. An inner member of the retrieval catheter may be engaged with the filter. Then outer retrieval sheath is advanced to collapse the filter and retrieve. The guidewire may be left in place if desired.
• Referring to the drawings and initially toFIG. 1 there is illustrated anembolic protection filter1 according to the invention, thefilter1 being suitable for deployment in a vasculature to filter undesired embolic material from the blood stream flowing through the vasculature.
• Thefilter1 comprises acollapsible filter body2 which in this case is supported by a collapsiblefilter support frame3. In this case the filter support is mounted on aninner tube8.
• Thefilter body2 has aninlet end4 and anoutlet end5. Theinlet end4 has one or more, and in this a single,large inlet opening6 which are sized to allow blood and embolic material enter thefilter body2. Theoutlet end5 has a plurality ofsmall outlet openings7 which are sized to allow through passage of blood but to retain undesired embolic material within thefilter body2. In this way, thefilter1 captures and safely retains any undesired embolic material in the blood stream within thefilter body2 while facilitating continued flow of blood through the vascular system. Emboli are thus prevented from flowing further downstream through the vascular system, which could otherwise have potentially catastrophic results.
• The relativelylarge inlet opening6 provide for the possibility of aspirating embolic material from within thefilter body2. This may be particularly advantageous if it is desired to leave thefilter1 in place in a vasculature for a long period of time, for example overnight, to assist in vascular recovery.
• Thefilter body2 may have a low-friction outer layer, for example a hydrophilic coating, to minimise frictional resistance during deployment and retrieval of thefilter1, and thefilter body2 may be of an oriented polymeric material, as described in International patent application No. PCT/IE01/00087, the relevant contents of which are incorporated herein by reference.
• Theinner tube8 has aguidewire lumen12 therethrough for passing thefilter1 over aguidewire10. Aguidewire10 can pass through the filter, however, in the deployed configuration the filter is independent of the guidewire. Thus, the guidewire can be moved independently of the filter without any associated movement of the filter. The arrangement allows relatively large radial forces to be exerted on the vascular wall without the risk of abrasion causes by movement of the deployed filter. In this way damage to the endothelium can be avoided.
• Thefilter1 is movable between a low-profile, collapsed configuration for movement through the vasculature, and an outwardly extended configuration for deployment in the vasculature in apposition with the vasculature wall.
• In the outwardly extended configuration, thefilter body2 is supported in an expanded position by thefilter support3 so as to maximise the internal volume of thefilter body2 to capture and safely retain as much embolic material as possible.
• Thefilter support3 supports thefilter body2 in the outwardly extended configuration in apposition with the vasculature wall to prevent blood flow bypassing thefilter1 between thefilter body2 and the vasculature wall.
• The support frame in this case defines aproximal support hoop15 which is connected to thetubular member8 by asupport arm16. Thesupport3 in this case also comprises a number of axially extendingportions17 which assist in providing body support to the filter in a vessel and assist in preventing rotation of the filter when deployed in the deployed configuration. The support may be of wire and may also comprise one or more stabilising hoops(s)18.
• In this case thetubular member8 terminates proximally of thedistal end5 of the filter. This has a number of advantages. It facilitates recrossing of thefilter1 with a guidewire and the distal free end of thetubular member8 may be readily snared for snaring and/or retrieval of the filter when it is desired to remove the filter from the vasculature.
• In the outwardly extended configuration, thefilter support3 exerts an outward radial force on thefilter body2 and the vasculature wall which results in a frictional force between thefilter body2 and the vasculature wall sufficient to retain thefilter1 in position against substantial longitudinal movement.
• In the invention the filter will not rotate or collapse in the absence of guidewire support. Conventional filters are coupled (directly or indirectly) to a wire—this wire enhances the stability of the filter. This invention describes a filter which will remain fully open and opposed to the vessel wall in the absence of any support from a guidewire. This is achieved by using a support frame which does not allow rotation in the vessel lumen. In general, a frame which lies in only one plane cannot remain apposed to the vessel wall without support from the guidewire. The design of the system is such that the filter must do considerable work to move longitudinally.
• In order to ensure that the filter is retained in position the filter apposition force generates a frictional force between the filter and the vessel. The frictional force generated by the filter is dependent on the contact area, the apposition force generated by the filter and the coefficient of static friction between the filter and the vessel. Locating the filter using frictional forces alone is a worst-case analysis as it does not include the effect of tapered vessels. These will increase the apposition force generated by the filter as it moves distally into a lumen of decreasing diameter.
• The radial apposition force of thefilter support3 is sufficient to retain the deployedfilter1 in position in the vasculature against substantial longitudinal movement, even if the guidewire, over which thefilter1 is delivered, is moved. No step, abutment or other stop means is required on the guidewire to prevent thefilter1 from migrating downstream in the vasculature. In this manner, the invention enables an interventional procedure to be performed using a standard guidewire. This enhances clinician freedom by enabling a clinician to choose the most appropriate medical guidewire for a particular interventional procedure, and/or a particular patient anatomy.
• In the case of a filter which has an integral tubular member the tubular member defines a lumen through which a guidewire can pass. In the invention such a guidewire passageway may be provided by a component of the delivery system such as a portion of a deployment pusher. Alternatively, the tubular member may be a separate component which is removed after the guidewire has passed through the filter. Thus, the member defining a guidewire pathway through the filter may be a movable or removable component.
• Referring to FIGS.2 to16 there are illustrated various steps in the use of an embolic protection device during an interventional procedure. Various steps in the method will be described and it will be appreciated that the various steps and the features of the various apparatus used in the method may be used independently of one another, for example in the methods and apparatus of other aspects of the invention.
• The filter does not necessarily itself have a predetermined lumen for passage of a guidewire. At various stages a lumen is defined when such a lumen is required. On loading of afilter20 into a delivery catheter21 a guidewire lumen is defined (FIG. 2) which is used for delivery of thefilter20 over a pre-positioned guidewire10 (FIG. 3). The lumen-definingmember22 may be removed (FIG. 3) and the filter is advanced to and deployed distal to a treatment location in the vasculature (FIGS. 4 and 5). Various procedures may be carried out such as balloon angioplasty and stenting (FIGS. 6 and 7). The filter may be retrieved into a retrieval catheter25 (FIGS.11 to15) and the filter removed.
• In this case thefilter20 comprises a filter body supported in the deployed configuration by asupport frame3 defining a largeproximal opening6 and having a snaring engaging element in the form of ahook26. In use, the filter is loaded into a delivery catheter L6 by inserting atubular element22 through the filter. The delivery catheter may be threaded onto a pre-deployedbare guidewire10, thetubular element22 guiding theguidewire10 through thefilter20 at the distal end of thedelivery catheter21. Once theguidewire10 has entered thedelivery catheter21 proximal to thefilter20 thetubular element22 may be removed. To facilitate this, the tubular element may be of C-shape in transverse cross section. Thedelivery catheter21 is then advanced over theguidewire10 to a location which is distal of a treatment site. Thefilter20 is deployed by pushing it out from the distal end of the delivery catheter, for example by using a pusher. The filter is then in the deployed open configuration distal to a treatment location (FIG. 5). Various procedures may be carried out at the treatment location, and embolic material released during the treatment procedures being captured in the filter. The treatment procedures may include deployment of astent29 from a stent delivery catheter threaded over theguidewire10. When it is desired to retrieve the filter aretrieval catheter25 is delivered over theguidewire10. Theretrieval catheter25 may be a snare catheter or a separate snare catheter may be delivered through the retrieval catheter. The snare may comprise alasso30 or the like which engages the snaringhook26 of the filter support frame. Theguidewire10 may then be withdrawn or left in place.
• In certain circumstances theguidewire10 could be retracted, or even removed completely (FIG. 8), without disturbing the position of the deployed filter in the vasculature. Anotherguidewire10A may be advanced through the filter (FIGS. 9 and 10). This may be particularly advantageous in the case of certain interventional procedures, for example in coronary applications as will be described in more detail below.
• Thesupport3 may be configured to distribute the outward radial force over a relatively large area of the vasculature wall to minimise local stress distributions.
• Many different designs of filter may be used such that on deployment, the filter applies a local radial force to the vasculature to substantially prevent movement of the filter relative to the vasculature in the deployed configuration. In the deployed configuration the filter is anchored to the vasculature. In some cases the filter comprises a filter body and a filter support frame to support the filter in the deployed configuration. The support frame and/or the filter body may comprise the anchor. The anchor may comprise a plurality of anchor elements which may be spaced-apart circumferentially around the filter when the filter is in the deployed configuration.
• Referring toFIG. 17 the filter frame includes aproximal support hoop31 with radially projecting vessel indentors orstabilisers32 to prevent longitudinal movement of the filter in the vessel. The frame may include a snaringfeature33 which may have a radiopaque marker34.
• Referring toFIGS. 18 and 19 the vessel indentors orstabilisers32 may also provide convenient attachment locations for attachment oftethers35. Thetethers35 may be interconnected at the proximal end by aconnector36 which may be radiopaque for ease of location to snare the filter for retrieval.
• Referring toFIG. 20 the filter may have anenlarged lip37 at the proximal end for engagement in a vessel to anchor the filter in a desired position.
• Referring toFIGS. 21 and 22 there is illustrated another filter which is apposed in a vessel. The filter has a retrieval mechanism somewhat like a closed drawstring arrangement with a mesh-like structure38, when deployed, which may be engaged by thedistal tip39 of a centering catheter (or any suitable snare) for collapsing the filter and drawing it into aretrieval catheter40.
• Another filter frame is illustrated in FIGS.23 to26. The frame has aproximal hoop41 and distally projectingarm42. X denotes terminations of the bifilar type to facilitate wrap-down of the filter as illustrated inFIGS. 24 and 25. Thus, the parking space occupied by the filter is optimised. In the deployed configuration in a vessel as schematically illustrated inFIG. 26 the filter apposes the vessel wall and rotation and translation of the filter in relation to the vasculature is prevented.
• In general, the filter applies sufficient radial force to remain stable in a vessel when in the deployed configuration. In addition, the filter remains correctly orientated even without a guidewire in place. Some filters of this type are illustrated in FIGS.27 to31. InFIG. 27 thefilter43 has body support. InFIG. 28 thefilter44 has stabilisingarms45. The filter ofFIG. 29 is in the form of ahoop46 with a number of inflection points47. There may be four or more such inflection points as illustrated.
• InFIG. 30 the filter has two axially spaced-apartsupport hoops48 which are interconnected by connectingarms49. The filter ofFIG. 31 has two offsethoops50. Any of these filters may be connected to a central tubular member by a rigid member(s) and/or by a tether(s). Many more arrangements with support in more than one place are envisaged.
• Thefilter51 ofFIG. 32 has body support provided by a nitinol tube or wire.
• To retrieve thefilter710, any suitable means, such as the hooked retrieval catheter (FIG. 250), or the looped retrieval catheter (FIG. 251) may be used, in a manner similar to that described previously with reference toFIGS. 242 and 243.
• Referring to FIGS.32 to39 there is illustrated adelivery catheter200 which may be used with a filter of the invention. This catheter is described in detail in our co-pending U.S. Ser. No. 10/180,980, the relevant contents of which are incorporated herein by reference. Thedelivery catheter200 comprises acatheter body202 which extends between aproximal end203 and adistal end204, a restrainingsheath210 at thedistal end204 of thecatheter body202, and an elongate actuator, which is provided in this case in the form of astainless steel wire209.
• Thecatheter body202 comprises aproximal hypotube portion205 and a radially offsetdistal spring pusher206. As illustrated inFIGS. 34 and 35, the pusher106 is fixedly attached to thehypotube205 in a side-by-side overlapping arrangement with the proximal end of thepusher206 located proximally of the distal end of thehypotube205.
• Thepusher206 has aguidewire lumen16 extending through thepusher206 with anopening217 at the proximal end of thelumen216 for passage of aguidewire222 through thelumen216 and out through the proximal guidewire opening217 (FIG. 35). Thedelivery catheter200 is thus configured to be passed over theguidewire22 in a rapid-exchange manner.
• Thepusher206 tapers proximally inwardly at theopening217 for a smooth crossing profile.
• When assembled, thehypotube205 and thepusher206 are located substantially side-by-side. This side-by-side assembly of thehypotube205 relative to thepusher206 enables theguidewire222 to exit through theproximal guidewire opening217 smoothly and substantially parallel to the longitudinal axis of thecatheter200. In particular, the passage of theguidewire222 through theproximal guidewire opening217 does not increase the overall profile of thecatheter200.
• Aconnector shaft212 is fixed to thesheath210 with theshaft212 extending proximally over thepusher206 towards the distal end of thehypotube205. The proximal end of thesheath210 overlaps the distal end of theshaft212, and amarker band213 is located at the distal end of theshaft212 between theshaft212 and thesheath210.
• Theactuator wire209 extends distally through anactuator lumen232 in thehypotube205, out of theactuator lumen232 at the distal end of thehypotube205, externally along thepusher6 to the proximal end of theshaft212. Thewire209 is attached to the exterior surface of theshaft212, for example by bonding. By attaching thewire209 to the exterior of theshaft212, this arrangement provides for more space within thepusher lumen216 for guidewire passage. In addition, attachment of theactuator wire209 to the exterior of theshaft212 is an easier step to achieve from a manufacturing viewpoint than attachment to the interior of the relativelylong shaft12.
• The restrainingsheath210 and theconnector shaft212 are movable in a sliding manner relative to thecatheter body202. When thesheath210 extends distally of a distal end of thespring pusher206, thesheath210 defines aninternal reception space211, as illustrated in FIGS.36 to38. A collapsedembolic protection filter301 may be received within thereception space211, where thefilter231 will be restrained by thesheath210 in a low-profile configuration during delivery to a desired site in a vasculature. A suitable material for thesheath210 is polyethyleneterephthalate (PET).
• The distal end of theshaft212 is flared outwardly (FIG. 38). During delivery of thefilter231, the distal end of thepusher206 is spaced proximally of the distal end of theshaft212, and the proximal end of an innertubular member236 of the filter is partially inserted into the flaredshaft212. This arrangement provides a bridge in stiffness between the relativelystiff shaft212 and the relatively stiff innertubular member236 of thefilter231. Thus the possibility of buckling of the relativelyflexible sheath10 is minimised. The distal end of thepusher206 is engagable with the innertubular member236 of thefilter231 upon retraction of thesheath210 to deploy thefilter231 out of thereception space211.
• As illustrated inFIG. 39, at theproximal end203 of the catheter200 adistal handle208 is provided for gripping thecatheter body202 and aproximal handle214 is provided for gripping theactuator wire209. Thedistal handle208 is injection moulded over thehypotube205 and theproximal handle214 is crimped to the proximal end of thewire209.
• Thehandles208,214 are movable relative to one another in a telescoping manner with theproximal handle214 sliding within thedistal handle208. Movement of thehandles208,214 is limited by means of stop means. Abutment of an outwardannular protrusion233 on theproximal handle214 against the proximal end of thedistal handle208 prevents further movement of theproximal handle214 distally relative to thedistal handle208. Engagement of ashoulder234 on theproximal handle214 with an inwardannular protrusion235 on thedistal handle208 prevents further movement of theproximal handle214 proximally relative to thedistal handle208. Areleasable safety clip237 is provided to maintain thehandles208,214 fixed relative to one another.
• When thecatheter200 is assembled thesheath10 is directly connected to theproximal handle214, and thepusher206 is directly connected to thedistal handle208. Movement of theproximal handle214 proximally relative to thedistal handle208 moves thewire209, theconnector shaft212 and thesheath210 proximally relative to thepusher206 to facilitate deployment of thefilter231 from within thereception space211.
• Thedelivery catheter200 may be used to deliver theembolic protection filter231 through a vasculature and to deploy theembolic protection filter231 downstream of a stenosed region in the vasculature to prevent potentially harmful emboli, which may be released into the blood stream during treatment of the stenosis, such as by a stenting procedure, from migrating further through the vascular system.
• Referring to FIGS.40 to54 the use of thedelivery catheter200 will now be described in relation to afilter301 of the invention which hastubular member306 with a distal end that is spaced proximally from the distal end of the filter. Such as arrangement facilitates removal replacement of a guidewire and can also be readily snared and retrieved as described herein.
• In use, aloading device310 is partially inserted into thereception space211 of thesheath210. A pushingdevice311 is then threaded through thetubular member306 of thefilter301 and extended into thereception space211, as illustrated inFIG. 40.
• By moving the pushingdevice311 proximally, anengagement stop312 on the pushingdevice311 engages the distal end of thetubular member306 and thefilter301 is moved towards the loading device310 (FIG. 10). Continued proximal movement of the pushingdevice311 pushes thefilter301 through theloading device310, thereby collapsing thefilter301, and into the reception space11 (FIG. 41).
• Thecatheter200 with thecollapsed filter301 received within the reception space11 are then moved together proximally away from the loading device310 (FIG. 42).
• The method of collapsing thefilter301 and loading thefilter301 into thereception space211 is similar to that described in International patent application number PCT/IE01/00052, the relevant contents of which are incorporated herein by reference.
• Next theguidewire222 is inserted into avasculature315 and advanced through thevasculature315 until theguidewire222 has crossed a site of interest in the vasculature315 (FIG. 44). A typical site of interest is a stenosed ordiseased region316 of thevasculature315. Thedelivery catheter200 is then threaded over theguidewire222 by inserting the proximal end of theguidewire222 into theguidewire lumen216 at the distal end of thepusher206, through thelumen216, and out of thelumen216 through theproximal guidewire opening217. Thecatheter200 is advanced over theguidewire222 in a rapid-exchange manner until thereception space211 is located downstream of the stenosis316 (FIG. 45).
• To deploy thefilter301 at the desired site in thevasculature315 downstream of thestenosis316, the proximal handle14 is moved proximally while holding thedistal handle208 fixed, thereby causing thepull wire209 and theconnector shaft212 to be pulled proximally. Because theconnector shaft212 is attached to thesheath210, thesheath210 also moves proximally while thepusher206 does not move. In this way, thecollapsed filter301 is uncovered by thesheath10 while the distal end of thepusher206 abuts the proximal end of thetubular member306 of thefilter301. Thedelivery catheter200 thus enables the self-expandingfilter301 to expand outwardly to a deployed configuration. The distal end of thepusher6 acts as an abutment for a controlled, accurate deployment of thefilter301 at the desired site in thevasculature315.
• When the filter230 has been fully deployed at the desired site in thevasculature315, thedelivery catheter200 is withdrawn from thevasculature315 over theguidewire222 in a rapid-exchange manner to leave the deployedfilter301 in place in the vasculature315 (FIG. 48).
• Various procedures can be carried out using the guidewire such as an angioplasty using a balloon320 (FIG. 49) or a stenting procedure with a stent321 (FIG. 50). On completion of the procedures a retrieval device such as aretrieval catheter325 or snare may be used to retrieve the filter (FIGS.51 to53). Theguidewire222 may be left in place or removed.
• In FIGS.55 to57 there is illustrated anotherdelivery catheter600 according to the invention, which is similar to thedelivery catheter200 and similar elements are assigned the same reference numerals. In this case the distal end of theshaft212 is not flared outwardly, and the proximal end of the innertubular member306 is not inserted into theshaft212, during delivery of theembolic protection filter610.
• Instead a bridgingsleeve601 is provided mounted around theshaft212 distally of themarker band213, as illustrated inFIG. 57. Thesleeve601 extends distally of the distal end of theshaft212, such that the proximal end of the innertubular member306 of thefilter610 may be partially inserted into thesleeve601 during delivery of the filter610 (FIG. 57). This arrangement provides a bridge in stiffness between the relativelystiff shaft212 and the relatively stiff innertubular member306 of thefilter610. Thus the possibility of buckling of the relativelyflexible sheath210 is minimised.
• It is noted that thefilter610 of FIGS.57(a) to57(c) is of a different configuration to the filter described previously. In particular the innertubular member306 of thefilter610 does not have any step formations or protrusions at the proximal end of the innertubular member306.
• The delivery catheter of the invention is also suitable for over-the-wire exchange over a guidewire. The rapid exchange configuration is not essential.
• Referring to FIGS.58 to61 there is illustrated one means of temporarily providing a tubular lumen in a filter to facilitate delivery of the filter to a desired location. In this case an introducer tool is in the form of a C-shapedtubular member60 with a distal peel-back feature61. The tool is inserted into the distal end of thefilter62 as illustrated inFIG. 58. The filter is loaded into adistal pod63 of a delivery catheter64 (FIG. 58) and the distal end of thedelivery catheter64 is threaded over the proximal end of a deployedguidewire65. When the guidewire has passed through the filter the introducer may be pulled away and removed as illustrated inFIG. 61.
• In another arrangement illustrated in FIGS.62 to65 thedelivery catheter70 may itself be provided with amember71 defining a temporary tubular member for a guidewire. The tubular member may also function as a pusher. In one case once the guidewire has traversed thefilter62 thetubular member71 may be positioned proximal of the filter during delivery and deployment (FIGS.63 to65). In another case (FIGS.66 to68) thetubular member71 may extend through the filter up to the stage when the delivery catheter is being withdrawn.
• Thepusher71 may pass through the centre (FIGS. 71 and 72) of the filter or may run beside the filter (FIGS. 69 and 70).
• InFIGS. 73 and 74, there is illustrated anotherembolic protection filter520 according to the invention. In the case offilter520, theguidewire lumen521 through thefilter520 is defined by twotelescoping tubes522,523. Theproximal tube522 is fixed to thefilter520 at the proximal end of thefilter520, and thedistal tube523 is fixed to thefilter520 at the distal end of thefilter520.
• In the deployed configuration ofFIG. 73, thedistal tube523 telescopes proximally over theproximal tube522 so that the overall parking space of thefilter520 in a vasculature is minimised. In addition thedistal tube523 is spaced distally of theguidewire aperture112 to facilitate crossing of thefilter520 with a guidewire without requiring the guidewire to be threaded through thetubes522,523.
• In the collapsed configuration ofFIG. 74, thedistal tube523 telescopes distally over theproximal tube522 so that theguidewire lumen521 is defined through the entire length of thefilter520 when collapsed, for example in apod524 of adelivery catheter525.
• The invention also envisages the use of adelivery catheter650, as illustrated in FIGS.75 to89, which is particularly suitable for delivering anembolic protection filter651, as illustrated inFIG. 77, thefilter651 not having an inner tubular member to define a guidewire lumen through thefilter651.
• Thedelivery catheter650 comprises an outertubular member652, and an innertubular member653, the innertubular member653 being movable distally relative to the outertubular member652 from a delivery configuration (FIG. 76) to a deployment configuration (FIG. 78).
• In the delivery configuration, thecatheter650 defines areception space654 for receiving thefilter651 in a collapsed configuration, as illustrated inFIG. 77. When the innertubular member653 is moved distally relative to the outertubular member652, thefilter651 is pushed distally out of thereception space654 by means of an engagement between ashoulder655 of the innertubular member653 and thecollapsed filter651.
• The invention provides features to enable a guidewire to be repositioned across the filter. It may be necessary to be able to replace the guidewire if the wire became accidentally withdrawn by the user during the procedure. It may then be necessary to replace the wire in order to access the lesion with other devices such as a balloon or stent catheter or even the filter retrieval catheter. Merely advancing a wire up to the filter is unlikely to provide sufficient support in all cases. Guidewire replacement may also be needed if the user desires to use a wire with different properties during the procedure. For example a very torqueable wire may be ideal for initially accessing and crossing the lesion, and may have adequate support to enable the filter to be delivered and deployed, but may not have sufficient support to enable a stiffer stent delivery system to reach the lesion. The invention facilitates removal of the first wire and replacement with a more supportive guidewire to facilitate use of the stent delivery system. This may be achieved without having to use an additional exchange catheter.
• This invention describes a filter which comprises a guidewire recrossing feature, wherein this feature may comprise some or all of a guiding funnel, a pathway and a blood restrictor. A guiding funnel is used as this operation will be performed “blind”. In general, it would be difficult to replace a guidewire through a tubular lumen while the filter is in the patient. In the invention the guidewire may be passed through the distal filter neck. The distal cone of the filter will act as a guiding channel. However the guidewire tip is very flexible—if it is to open a “valve” or blood restrictor it will need to have good push. In order to provide this push it is necessary to restrain the guidewire tip within a relatively narrow channel—this channel is provided by the filter neck. A restrictor may be provided to prevent any loss of embolic material while the first guidewire was absent—during which period the neck of the filter would be an open hole if no restrictor were present. This restrictor is intended simply to close and prevent blood flow in the absence of a guidewire. Once there is no blood flow through the filter neck embolic material will not collect there and will not restrict the passage of the second guidewire.
• Various guideways may be provided for a guidewire to assist crossing of a filter. Referring to FIGS.79 to81 the pathway may be provided around the filter, for example in aside channel80. Aradiopaque feature81 may be provided on the filter to guide a user to the passageway. Alternatively the pathway may be through the filter to a single exit82 (FIG. 82), a separate exit83 (FIG. 83) or through thesame exit84 using a shortenedtubular member85 illustrated inFIG. 84 and described in more detail herein. In these cases the guidewire passage/hole may be sealed to prevent passage of embolic therethrough as will be described in more detail below.
• Referring now to FIGS.85 to92, there is illustrated anotherembolic protection filter50 according to the invention. Thefilter150 comprises a receiver to guide a docking device into association with thefilter150. In this case, the receiver is configured to guide a guidewire, such as theguidewire130, into theguidewire lumen112. The receiver is provided by afuel151 which diverges outwardly proximally, thefuel151 being mounted to thefilter150 to extend proximally of the inlet end of thefilter150.
• In this specification, the term funnel will be understood to mean any orifice with a cross-sectional area that decreases with distance.
• Thefunnel151 may comprise a collapsible funnel body in the form of amembrane152, which in this case is supported by a collapsible funnel support, in the form of a plurality ofsupport fingers153. Thefingers153 are pivotally mounted to thefilter50 and are biased to move thefilter membrane152 from a collapsed configuration for movement through the vasculature, to an outwardly extended configuration for guiding theguidewire130, as illustrated inFIG. 86. Thefunnel151 may be of a radiopaque material.
• Thefunnel151 may be used to guide theguidewire130 along a pathway that enables theguidewire130 to cross thefilter150. Thefunnel151 allows the procedure of leading thesmall diameter guidewire130 through the small diameter guidewire lumen of thefilter150 to be performed more easily by guiding the tip of theguidewire130 towards the proximal end of theguidewire lumen158.
• Use of thefunnel151 is particularly beneficial in the case where it is desired to lead theguidewire130 through the guidewire lumen while thefilter150 is deployed in the vasculature, as illustrated in FIGS.87 to89. Thefunnel151 enables a clinician to accurately and quickly thread theguidewire130 through the guidewire lumen without risk of puncturing the filter body or of disturbing thefilter50 from its deployed position in the vasculature in apposition with the wall of the vasculature.
• Thefilter150 further comprises at least one, and in this case two,seals160,161 to seal theguidewire lumen158 to prevent embolic material from passing through theguidewire lumen158, when thefilter150 is in use in the vasculature.
• Theseals160,161 are self-closing. In this case oneseal160 located at the proximal end of thefilter150, and theother seal161 located at the distal end of thefilter150.
• Theproximal seal160 may be in the form of a tubular member of a soft membrane material. Theguidewire lumen158 extends through thetubular seal160 and theseal160 is closable down to seal theguidewire lumen158.
• Thedistal seal61 is in the form of a tubular member with two or more, and in this case seven, circumferentially overlapping flaps, as illustrated inFIG. 92. Thisseal161 is also closable down to seal theguidewire lumen158.
• It will be appreciated that theguidewire lumen158 can be provided as any suitable passageway through thefilter150. Theguidewire lumen158 does not have to be located along the central axis of thefilter150. Theguidewire lumen158 may be radially offset from the longitudinal axis of thefilter150.
• When theguidewire30 is extended through theguidewire lumen158, theseals160,161 self-close around theguidewire130 to prevent emboli flowing through theguidewire lumen158. Upon removal of theguidewire130 from theguidewire lumen158 while thefilter150 is deployed in the vasculature, theseals160,161 self-close down to completely close off theguidewire lumen158.
• In this manner, theseals160,161 ensure that no blood flow potentially carrying harmful embolic material can pass through theguidewire lumen158. All blood flows into the filter body through the inlet openings and out of the filter body through the small outlet openings, thereby trapping and safely retaining the undesired embolic material within thefilter150.
• After an embolic protection filter has been delivered over a guidewire and deployed in a vasculature, it is not always possible to withdraw the guidewire from the vasculature before collapsing and withdrawing the filter from the vasculature.
• However in some cases it may be necessary to withdraw the guidewire over which the filter was delivered while leaving the filter deployed in the vasculature.
• Examples of when this need may arise are:
• • when a high torque guidewire is used to facilitate filter delivery and deployment, and a stiffer guidewire is subsequently used to provide additional support during delivery and deployment of a stent;
  • when a guide catheter has prolapsed;
  • when a guidewire is withdrawn into a guide catheter to accelerate rate of resolution of a spasm.
• When this need does arise, thefilter50 of the invention may be used to filter potentially harmful emboli from a vasculature when the guidewire is withdrawn, while the filter remains deployed in the vasculature, as illustrated in FIGS.93 to110.
• Afirst guidewire130 is introduced into and advanced through thevasculature121 to cross the treatment location122 (FIG. 93), and thefilter150 is delivered trough thevasculature121 and deployed distally of the treatment location122 (FIGS.94 to97), in a manner similar to that described previously.
• In the outwardly extended configuration, the deployedfilter150 is retained in position in thevasculature121 against substantial longitudinal movement by the radial apposition force of the filter body against the wall of thevasculature121. Thefirst guidewire130 can thus be withdrawn from the guidewire lumen of thefilter150, and completely withdrawn from thevasculature121 without disturbing the outwardly extended configuration of thefilter150 in thevasculature121.
• The deployedfilter150 is retained in position in thevasculature121 against substantial longitudinal movement by means of the radial apposition force exerted by the filter support on the filter body and the vasculature wall, as described previously.
• Asecond guidewire140 is then introduced into thevasculature121 and advanced through thevasculature121 until thesecond guidewire140 crosses the desiredtreatment location122. The tip of thesecond guidewire140 is guided towards the proximal end of the guidewire lumen by engagement of the guidewire tip with thefunnel151, and thesecond guidewire140 is then lead through the guidewire lumen.
• Astent136 may then be delivered through thevasculature121, and deployed at thetreatment location122 using thestent delivery catheter135. In this case, thestent delivery catheter135 passes over thesecond guidewire140. After completion of the interventional procedure, theretrieval catheter120 is advanced to cross thestent136 and thetreatment location122, and the tip125 is engaged with thefilter150. As the tip125 passes through thefunnel151, the funnel115 is caused to collapse down to the collapsed configuration. Thefilter150 is then collapsed and retrieved into theretrieval catheter120 and withdrawn from thevasculature121. Upon collapse of thefilter1, the apposition of the filter with thevasculature121 is released.
• Thefilter150 ensures any embolic material generated during the interventional procedure is captured and safely removed from thevasculature121.
• Thesecond guidewire140 may be of a different diameter, or have different material properties to thefirst guidewire130. It may thus be easier or more suitable for the clinician to advance thestent delivery catheter35 over thesecond guidewire140 rather than over thefirst guidewire130. For example, it is sometimes the case that ahigh torque guidewire130 is used to facilitate filter delivery and deployment, and astiffer guidewire140 is used subsequently to provide additional support during delivery and deployment of a stent.
• In some cases, it may be necessary or desirable to withdraw thesecond guidewire140 from thefilter150 and thetreatment location122 after deployment of thestent136, and then to advance a third guidewire through thevasculature121 to the filter, theretrieval catheter120 then being advanced over the third guidewire to retrieve thefilter150. This invention enables such a procedure to be carried out.
• Furthermore withdrawing a guidewire into a guide catheter may accelerate the resolution of spasm and reduce the risk of ischaemia.
• Referring to FIGS.111 to114, there is illustrated another retrieval catheter according to the invention, which is similar to the retrieval catheter of FIGS.190 to192. In this case, the catheter body23 defines aguidewire lumen151 radially offset from the coupling member24. Theguidewire lumen151 extends through only part of the catheter body23 to facilitate passage of the catheter body23 over a guidewire, such as theguidewire140, in a rapid exchange manner.
• In use, theretrieval catheter150 may be used to retrieve thefilter1 deployed in thevasculature21.
• In one possible procedure, thesecond guidewire140 is not led through theguidewire lumen12 of thefilter1. Instead thesecond guidewire140 is advanced until theguidewire140 has crossed the treatment location and the guidewire tip is proximally of the filter1 (FIG. 113). Thefilter1 is then retrieved into the catheter body23. During this procedure theretrieval catheter150 may be advanced distally off the end of theguidewire140.
• FIG. 115 illustrates anotherfilter170 according to the invention. In this case, thefunnel151 is mounted to thefilter170 distally of the inlet end of thefilter170, so that thefunnel151 is located at least partially within thefilter170.
• It will be appreciated that the receiver may be detachably mounted to the filter. For example, the receiver may be mounted to the filter after deployment in a vasculature, and/or may be detached from the filter before retrieval of the filter from a vasculature.
• In addition, the receiver may be radially offset from the longitudinal axis of the filter.
• Referring toFIGS. 116 and 117, there is illustrated anotherfilter180 according to the invention. The funnel is provided, in the case offilter180, by slopingwalls181 of the filter body at the inlet end. As theguidewire130 is advanced to thefilter180, the tip of theguidewire130 meets the slopingwalls181 of the filter body and is guided distally inwardly towards the proximal end of the guidewire lumen. In this manner, the slopingwalls181 enable theguidewire130 to be easily and quickly threaded into the guidewire lumen.
• The angle of inclination α of these slopingwalls181 can be altered, as indicated inFIG. 117, to suit the characteristics of the interventional procedure, and/or the vasculature, and/or the guidewire.
• The large inlet openings enable substantially unrestricted flow into the filter body, and thesloping walls81 may be radiopaque material to aid guidewire passage.
• FIG. 118 illustrates afurther filter190 according to the invention. In this case, thefilter190 has aguidewire aperture192 for passing thefilter190 over theguidewire130, and thefilter190 has a single, large inlet opening191 at the inlet end of thefilter190. The single, large inlet opening191 provides no resistance to blood flow into the filter body.
• The slopingwalls192 at the outlet end of thefilter190 provides the funnel, in this case, to guide theguidewire130 towards theguidewire aperture192.
• It will be appreciated that the outlet openings are smaller, in this case, than the guidewire diameter, thus theguidewire130 does not snag or pass through the outlet openings but instead theguidewire130 is guided distally inwardly to theguidewire aperture192.
• The filter90 may have aguidewire aperture112 for passing the filter90 over theguidewire30, and the filter90 has a single, large inlet opening91 at theinlet end4 of the filter90. The single, large inlet opening91 provides no resistance to blood flow into thefilter body2.
• The slopingwalls190 at the outlet end of thefilter190 provides the funnel, in this case, to guide theguidewire130 towards theguidewire aperture192, as illustrated inFIGS. 119 and 120.
• It will be appreciated that the outlet openings are smaller, in this case, than the guidewire diameter, thus theguidewire130 does not snag or pass through the outlet openings but instead theguidewire30 is guided distally inwardly to theguidewire aperture192.
• As illustrated in FIGS.119 to121 thefilter190 further comprises a distal seal at theguidewire aperture192 in the form of an elastomeric self-sealingvalve400. Thevalve400 has co-operating flaps which meet centrally to close off theguidewire aperture192 when the guidewire is not extended through theaperture192, as illustrated inFIGS. 119 and 121. As the guidewire is pushed through theguidewire aperture192, the flaps of thevalve400 are forced apart to permit passage of theguidewire130, as illustrated inFIG. 120.
• It will be appreciated that thevalve400 could alternatively be provided in the form of four, two, or any other number of co-operating flaps.
• Referring to FIGS.122 to127 the guidewire exit hole may be sealed with a thinflexible membrane401 which can withstand any pressure differential across the filter but can be deformed by the guidewire tip to open the seal/membrane. Various options are possible such as those illustrated in FIGS.123 to126.
• Another option is to provide a seal in the form of an invertibleflexible tube402. The tube may haveslits403 for additional flexibility.FIG. 128 shows an initial guidewire in position,FIG. 129 shows the wire removed and the tube collapsed, sealing the hole. InFIG. 130 a new wire is shown being advanced through the filter, the advancing of the wire pushing the tube out of the filter neck and forming a seal with the new wire as illustrated inFIG. 131. The tube may be slits or slots for added flexibility as illustrated inFIG. 132.
• The guidewire exit hole may also be sealed by a flap valve or the like. Referring to FIGS.133 to135 aclosure flap410 is hingedly connected to thefilter411 by acurved lever412. Thehinge point413 is stepped back proximally from theflap410 so that the pressure drop across theflap410 does not cause theflap410 to open. Theflap410 is opened against the biasing of thelever412 on insertion of aguidewire415 as illustrated inFIGS. 134 and 135.
• It will be appreciated that the hinge may have a range of different constructions. For example, as illustrated inFIG. 136 ahinge416 may be provided by a flattened wire or ahinge417 may be formed by a narrowing of the lever as illustrated inFIG. 137.
• In another embodiment illustrated in FIGS.138 to140 adistal end420 of a filter may have a flattenedneck section421 which normally seals aguidewire aperture422 but which can be opened to facilitate passage of awire423.
• A further embodiment is illustrated in FIGS.141 to143 in which the filter distal guidewire aperture has a foam-like insert425 with slits to facilitate deformation of the foam as aguidewire426 is inserted whilst still maintaining a sealing engagement with theguidewire426.
• In the invention the retrieval device grips and retrieves the filter. Conventional filters are retrieved by using the guidewire to engage with the filter. This invention describes a retrieval device with one member which engages with and restrains the filter while a second member may envelop the filter. The retrieval device may function in the absence of a guidewire so that the filter can be retrieved even if the user has removed the guidewire and failed to replace it. This retrieval process may involve three stages: 1) Engage with the filter, 2) Decouple filter from vessel, 3) Retrieve the filter. Alternatively the retrieval may involve two stages: 1) Engage with the filter, 2) Retrieve the filter.
• The retrieval process is simple and reliable. The snare (or loop or lasso) designs described provide one of the most reliable and versatile methods. There is preferably a feature on the filter with which this snare will engage easily. This feature and the snare loop are preferably radiopaque for ease of visibility and positioning. For example a large radiopaque ball (or shepherds crook) inside the filter may be pulled proximal to the filter when snared and wrapped down.
• Referring in particular to FIGS.144 to146, there is illustrated aretrieval catheter620 according to the invention. Theretrieval catheter620 is suitable for retrieving a filter, deployed in avasculature621 distally of atreatment location622, such as a region of stenosis.
• Thecatheter620 comprises anouter catheter body623 and a coaxialinner coupling member624, thecoupling member624 having means for coupling to the filter especially a filter deployed in thevasculature621 to be retrieved.
• The coupling means is provided, in this case, by an arrow-head shapedtip625 on thecoupling member624. Thetip625 has twomale fingers626 for engagement with two correspondingfemale recesses627 on thefilter1.
• Themale fingers626 are moveable between a low-profile configuration and an outwardly protruding configuration for engagement with the filter. In this case, thefingers626 are of a resilient material, and are biased towards the outwardly protruding configuration.
• During introduction of theretrieval catheter620 through thevasculature621, thetip625 protrudes only partially distally of the distal end of thecatheter body623, so that theresilient fingers626 are maintained in the low-profile configuration. The protrudingtip625 prevents snagging of the open mouth of thecatheter body623 against any protruding parts of the vasculature wall. In addition thetip625 tapers distally inwardly for a smooth crossing profile.
• When theretrieval catheter620 has crossed thetreatment location622, thecoupling member624 is moved distally relative to thecatheter body623, to release theresilient fingers626 to move to the outwardly protruding configuration. Thecoupling member624 is then moved further distally into the filter until thefingers626 engage with therecesses627 of the filter.
• Therecesses627 may be defined in a more pronounced manner by providing inwardly protruding steps or abutments on the proximal end of the filter support against which thefingers626 may engage.
• Thecatheter body623 is next moved distally relative to the engagedfilter1 by maintaining the position of thecoupling member624, the distal end of thecatheter body623 is engaged with the proximal end of the filter body, thecatheter body623 is further advanced and thus the coupledfilter1 is collapsed down releasing the apposition force and is retrieved into thecatheter body623. When thecollapsed filter1 has been fully retrieved into thecatheter body623, theretrieval catheter620 is withdrawn with thefilter1 from thevasculature621.
• Thecoupling member624 of theretrieval catheter620 enables a deployed medical device, such as thefilter1, to be retrieved into theretrieval catheter620 with any retained embolic material within thefilter1 without requiring a step, or a clamp or any special stop features on the guidewire. Thus theretrieval catheter620 enables thefilter1 to be used in combination with any standard guidewire.
• In addition, it is not necessary to retract the guidewire to facilitate retrieval of thefilter1.
• In certain circumstances if the guidewire was withdrawn from the deployedfilter1 it would still be possible to retrieve thefilter1 using the retrieval catheter of the invention. This could speed up the overall procedure. Also in some cases it may be difficult to recross thefilter1 with a guidewire. Furthermore by obviating the need to recross thefilter1 with a guidewire, the possibility of a spasm being caused is minimised.
• FIGS.152 to165 illustrate theembolic protection filter1 and theretrieval catheter620 according to the invention, in use.
• Aguidewire630 is introduced into and advanced through thevasculature621 until theguidewire630 crosses the desiredtreatment location622. Adelivery catheter631 is then used to deliver theembolic protection filter1 through thevasculature621 over theguidewire630, thefilter1 being housed within adistal pod632 of thedelivery catheter631 in the collapsed configuration.
• Thefilter1 may in one case be loaded into adelivery catheter631 as described in International patent applications Nos. PCT/IE01/00052 and PCT/IE01/00053, the relevant contents of which are incorporated herein by reference. It will be appreciated that other loading alternatives are also possible.
• When thedistal pod632 has been advanced to a desired site distal to thetreatment location622, thepod632 is moved proximally relative to an inner pusher to deploy thefilter1 out of thepod632 into the outwardly extended configuration, as described in further detail in International patent applications Nos. PCT/IE01/00052 and PCT/IE01/00053. After complete deployment of thefiler1, thedelivery catheter631 is withdrawn from the vasculature621 (FIG. 11).
• In the outwardly extended configuration thefilter1 is in apposition with thevasculature621, thereby preventing blood flow from bypassing thefilter1 between thefilter1 and thevasculature621. The radial apposition force of the filter support against the filter body and the wall of thevasculature621 retains thefilter1 in position against substantial longitudinal movement, even if theguidewire630 is moved or indeed removed. In this way thefilter1 is prevented from migrating downstream in thevasculature621.
• An interventional procedure is then carried out at thetreatment location622. In the case illustrated, the interventional procedure is a stenting procedure using a self-expanding stent. However, a range of procedures are possible as alternatives to, or in addition to stenting, for example a balloon angioplasty procedure, a balloon-expandable stenting procedure, an atherectomy procedure, a lysis.
• Astent delivery catheter635 is used to deliver a stent, such as aself expanding stent636, through thevasculature621, thestent636 being held in a collapsed configuration by a restrainingsheath637 of thestent delivery catheter635.
• When thestent delivery catheter635 has been advanced to thetreatment location622, thesheath637 is moved proximally relative to aninner body638 of thecatheter635 to facilitate deployment of thestent636 at thetreatment location622.
• After complete deployment of thestent636, thestent delivery catheter635 is withdrawn from thevasculature621′ leaving the deployedfilter1 and the deployedstent636 in thevasculature621.
• Any embolic material generated during delivery or deployment of thestent636, or during withdrawal of the stent delivery catheter639 is captured and safely retained in the deployedfilter1.
• After completion of the interventional procedure, theretrieval catheter620 is introduced into thevasculature621, and advanced through thevasculature621 until thestent636 and thetreatment location622 have been crossed.
• Thefilter1 is simultaneously collapsed and retrieved into thecatheter body623 of theretrieval catheter620 and with it the captured embolic material, by engaging thetip625 with thefilter1, and then advancing thecatheter body623 distally over thecoupling member624 and the engagedfilter1.
• Upon collapse of thefilter1, the apposition of thefilter1 with thevasculature621 is released.
• When thefilter1 has been fully collapsed and retrieved into theretrieval catheter620, theretrieval catheter620 with thecollapsed filter1 and retained emboli therein are withdrawn from thevasculature621, leaving the deployedstent636 in place at thetreatment location622 in thevasculature621.
• In this way, thefilter1 may be used to capture and safely remove any embolic material which has been generated during the interventional procedure.
• An expandable balloon may be provided on the filter to enhance the outward radial force on the vasculature wall to retain the filter in position against substantial longitudinal movement. In use, the balloon may be inflated after deployment at the desired site in the vasculature to effectively anchor the filter in position. The balloon may be subsequently deflated before retrieval of the filter.
• FIGS. 164 and 165 illustrate another embolic protection filter300 according to the invention. The filter300 comprises acapture tether301 which extends externally of thefilter body2 from a proximal ring302, to which thetether301 is fixed, to a distal capture hoop303. The capture hoop303 is located around the distal core at theoutlet end5 of the filter300 when the filter300 is in the outwardly extended configuration, as illustrated inFIG. 164. The capture hoop303 is slidable over the filter body. To collapse and retrieve the filter300 into theretrieval catheter20, the coupling member24 engages thecapture tether301 and causes the capture hoop303 to move proximally. The coupling member24 may be engaged with thecapture tether301 using a hook, or loop, or any other suitable coupling means, as described previously. In this manner thefilter100 is compressed for retrieval into the catheter body23, as illustrated inFIG. 165.
• The coupling means may alternatively be provided by a male member in the form of ahook700, as illustrated inFIG. 166 for hooking around a receiver on thefilter1. Thehook700 may be used to couple the coupling member24 to any suitably configured embolic protection filter.
• For example, anembolic protection filter710, illustrated inFIGS. 168 and 169, has atether arm711 at a proximal end of thefilter710 around which thehook700 may be extended to couple the deployedfilter710 with the coupling member24 and thereby facilitate retrieval of thefilter710 into the catheter body23.
• FIGS.170 to173 illustrate furtherembolic protection devices720,725,730 according to the invention.
• Thefilter720 ofFIG. 170 has threetether arms721 which extend radially inwardly from thefilter body2 to meet at acentral point722. Thehook700 may be extended around any one of thetether arms721 to couple the coupling member24 to thefilter720. This tether arrangement enables thefilter720 to be retrieved with a central, axial pull force.
• In thefilter725 ofFIG. 172, the threetether arms726 extend radially inwardly and distally to thecentral point727. In this manner thecentral point727 is stepped back distally from the single,large inlet opening6 to minimise the possibility of embolic material becoming caught or hung up on thetether arms726.
• Thefilter730 ofFIG. 173 has a central ring332 to which the tether arms331 are fixed.
• FIGS.174 to178 illustrate theembolic protection filter710, being retrieved into the catheter body24 usinggrasping jaws906. In this case, thejaws906 compriseserrated edges750 to achieve a secure grasping of thetether arm711. In this manner, thefilter710 may be coupled to the coupling member24 and retrieved into the catheter body23. Theretrieval catheter905 is withdrawn from the vasculature after retrieving thefilter710 leaving theguidewire30 remaining in the vasculature.
• The tether arms of any of the above described embodiments may be mechanically attached at the central point, and/or at the central ring, and/or to thefilter body2, for example by bonding, or welding, or brazing. Alternatively the tether arms may be provided integral with the mesh/membrane of thefilter body2. The tether arms could also be provided as a fibre from such a mesh.
• In theembolic protection filter410 ofFIG. 179 thetether arm411 is located within thefilter410. To couple the coupling member24 to thefilter410, thehook100 is extended into thefilter410 and hooked around thetether arm411.
• In thefilter413 ofFIG. 180, twotether arms412 are provided. It will be appreciated that any suitable number of tether arms may be provided at either end of an embolic protection filter, and/or within the filter.
• Referring toFIGS. 181 and 182, there is illustrated anotherembolic protection filter500 according to the invention, which is similar to thefilter720.
• In this case, thefilter500 comprises an innertubular member502 to which the threetether arms501 are fixed. Thetubular member502 defines a guidewire lumen503 therethrough for passing aguidewire530 through the tubular member502 (FIG. 181).
• Thetubular member502 extends through only part of thefilter500. As illustrated inFIG. 182, this enables theguidewire530 to cross thefilter500 without having to tread theguidewire530 through the relatively small diameter guidewire lumen503.
• This configuration may be particularly advantageous when it is desired to cross thefilter500 with a guidewire while thefilter500 remains deployed in a vasculature. In this circumstance, the distal end cone of the filter body may act as a guide to guide theguidewire530 through theguidewire aperture112.
• Thetubular member502 of theembolic protection filter510 illustrated inFIG. 183 also extends only partially through thefilter510 to facilitate crossing of thefilter510 with theguidewire530 without requiring threading of theguidewire530 through thetubular member502.
• It will be appreciated that any other suitable means for coupling the deployedfilter1 with the coupling member24 of theretrieval catheter20 may be employed to facilitate retrieval of thefilter1 into the catheter body23, for example the coupling member24 may be provided with one or more female recesses for engagement with one or more corresponding male protrusions on thefilter1.
• Alternatively a female member on the coupling member24 may be provided in the form of aloop701, as illustrated inFIG. 167, for looping around amale stub702 protruding from thefilter1.
• Referring to FIGS.184 to189 there is illustrated anotherretrieval catheter905 according to the invention. In this case, the coupling member24 comprises a pair ofjaws906 at the distal end of the coupling member24. Thejaws906 are movable between an outwardly protruding configuration (FIG. 186) and a low-profile configuration (FIG. 187) to grasp thefilter1.
• Thejaws906 are biased towards the low-profile configuration and may be moved outwardly by moving an innerelongate actuator907 longitudinally distally relative to thejaws906 to engageelbows908 on theJaws906 and thereby move thejaws906 outwardly in a camming arrangement (FIG. 186).
• Thejaws906 define a recessedportion909afor co-operation with a protrudingneck909bon the proximal end of thefilter1 during grasping of thefilter1, as illustrated inFIG. 187.
• In use, theretrieval catheter905 is advanced through thevasculature21 in the low-profile configuration until thejaws906 are proximally adjacent to the deployedfilter1. Theactuator907 is then moved distally relative to thejaws906 to cam thejaws906 open, and the openedjaws906 are advanced until the recessedportion909aof thejaws906 are around the protrudingneck909bof thefilter1. By moving theactuator907 proximally relative to the coupling member24 thejaws906 are released to move inwardly to grasp thefilter1 around theneck909b. The graspedfilter1 may then be retrieved into the catheter body23 by moving the catheter body23 distally relative to the coupling member24.
• It will be appreciated that thejaws906 may grasp any suitable part of thefilter1 to facilitate retrieval. For example, thejaws906 may grasp thefilter1 at theinlet openings6, as illustrated inFIGS. 188 and 189.
• As illustrated in FIGS.190 to191, thejaws906 may alternatively be biased outwardly. During advancement of theretrieval catheter905 through thevasculature21, thejaws906 are restrained in the low-profile configuration by the catheter body23 (FIG. 190). To move thejaws906 outwardly, the coupling member24 is moved distally relative to the catheter body23 to release thejaws906 to spring outwardly (FIG. 191).
• To subsequently move thejaws906 inwardly when the recessedportion909aof thejaws906 are around the protrudingneck909bof thefilter1, the catheter body23 is moved distally relative to the coupling member24 to engage thejaws906 and move thejaws906 inwardly to grasp thefilter1 around theneck909b. Thefilter1 is then retrieved into the catheter body23 by advancing the catheter body23 filter distally relative to the coupling member24 and the grasped filter1 (FIG. 192).
• Alternatively, the coupling member24 may have amagnetic tip25 for magnetic coupling to an oppositely charged magnetic portion of thefilter1.
• FIGS. 193 and 194 illustrate anotherretrieval catheter940 according to the invention. In this case, theretrieval catheter940 comprises asecond coupling member941, which is movable relative to the first coupling member24. In this way, thesecond coupling member941 may be used to axially elongate an element of the deployedfilter1, such as thefilter support frame3, to collapse thefilter1 to the low-profile configuration for retrieval into the catheter body23. In this case, thesecond coupling member941 acts as a pusher and is movable distally relative to thetip25. By engaging thetip25 with thefilter support3 and then moving thesecond coupling member41 distally to engage adistal end42 of thefilter support3, thefilter support3 is axially elongated and thefilter1 is collapsed from the outwardly extended configuration ofFIG. 194 to the collapsed configuration.
• Thecollapsed filter1 may then be retrieved by moving the catheter body23 distally relative to thetip25 and the engagedfilter1.
• Referring to FIGS.195 to201 there is illustrated another filter retrieval system of the invention. In this case a snare type retrieval is used for afilter850 with aguidewire851 extending through atubular member852. Thetubular member852 has a projectinghead portion853 with an associatedmarker band854 for engagement by a lasso orloop855 delivered through aretrieval catheter856 into which the filter is retrieved as illustrated.
• Another embodiment is illustrated in FIGS.202 to206 which is used for retrieval of afilter860 which does not have a tubular member. In this case the filter frame has asnare receiving projection861 which is engaged by a snare lasso/loop862 and thefilter860 is retrieved into aretrieval catheter863, as illustrated.
• FIGS.207 to212 illustrate an embodiment in which afilter870 is used which has a partialtubular member871 but the guidewire does not extend through the tubular member. This arrangement is similar to that of FIGS.195 to201 above and like parts are assigned the same reference numerals. The snare loop is in this case free of the guidewire and may be more easily manipulated. In both cases the snare loop may be rendered radiopaque to facilitate snaring with the filter for retrieval.
• Further retrieval devices are illustrated in FIGS.213 to218 in which the retrieval devices havearms950 which open out when anouter sheath951 is retracted and thus create a large inlet mouth which can readily trap the filter frame, particularly if radiopaque features such as marker bonds are used. When thearms950 are in position distal to the snare feature of the frame/filter the arms are closed again, for example by re-advancing asheath951 which collapses thearms950 and trapstether feature952 of the filter, for example behind a step or tooth on the arm(s).
• Referring to FIGS.219 to224 the filter frame may have a retrieval feature such as anodule960 which may be engaged by a suitable snare such as a snare loop or lasso961 which is then tightened or simply pulled back to collapse the frame and retrieve the filter. The centeringtip962 may be used to assist guiding of the snare loop.
• Various alternative filter designs with an integral snare feature are possible. For example, inFIGS. 225 and 226 the filter frame has a projectingarm970 which may be engaged by a snare.
• Anexpandable engagement member971 may be used to catch a drawstring type arrangement972 (FIGS. 227, 228) or to catch internal wires/tethers/fibers/strings of the filter (FIGS. 229, 230).
• Referring toFIGS. 231 and 232 there is illustrated the size of asnare990 to snare afilter991. The snare engagable features of the filter in this case are provided byindents992 in the support arms over which thesnare loop990 is engaged.
• The snaring of a filter of any type is illustrated in FIGS.233 to237, In this case thefilter995 is positioned distal to astent996 and asnare loop997 is advanced through the stent to engage the filter as illustrated, allowing the filter to be at least partially collapsed for retrieval.
• InFIGS. 238 and 239 there is illustrated the snaring of afilter1 as illustrated inFIG. 1 using asnare loop998.
• A furtherembolic protection filter700 according to the invention is illustrated inFIGS. 240 and 241. Thefilter700 comprises a collapsiblefilter support structure701 and acollapsible filter body702.
• In the expanded, deployed configuration ofFIG. 240, thesupport structure701 does not have an inner tubular member to define a guidewire lumen for passing a guidewire703 through. When thefilter700 is collapsed, the support structure collapses down into a smaller diameter tubular structure, as illustrated inFIG. 241. In this collapsed configuration, thesupport structure701 defines the guidewire lumen for the guidewire703. In this manner thesupport structure701 isolates thefilter body702 from the guidewire703, and thus prevents thefilter body702 from becoming fixed to the guidewire703 during delivery or retrieval of thefilter700.
• Thefilter700 may be retrieved using any suitable means, such as the hooked retrieval catheter (FIG. 242), in a manner similar to that described previously or the hooped retrieval catheter (FIG. 243), in a manner similar to that described previously.
• If it is desired to remove the guidewire703 from thefilter700 and recross thefilter700 with a second guidewire704, the guidewire704 may be threaded through one of the relatively large inlet openings705 instead of through the relatively small proximal collar706 of thesupport structure701, as illustrated inFIG. 244. This enables a faster and more convenient means of recrossing thefilter700.
• In addition, the distal collar707 of thefilter support structure701 is spaced proximally of the distal end of thefilter700 to facilitate crossing of thefilter700 with the second guidewire704 without requiring the guidewire704 to be threaded through the distal collar707 (FIG. 244).
• Thefilter700 can be retrieved after crossing thefilter700 with the second guidewire704 using any suitable means (FIGS. 245 and 246).
• Referring toFIGS. 247 and 248, there is illustrated anotherembolic protection filter710 according to the invention, which is similar to theembolic protection filter700 ofFIGS. 240 and 241, and similar elements inFIGS. 247 and 248 are assigned the same reference numerals.
• Thefilter710 is longitudinally shorter than thefilter700. In addition thefilter support structure701 ends in an opendistal mouth711 in thefilter710 and no distal collar is provided in thefilter710, as illustrated inFIG. 247.
• In thefilter710, thefilter body702 is isolated from the guidewire703 by the collapsed filter support structure701 (FIG. 248), in a manner similar to that described previously with reference toFIG. 241.
• Thefilter710 may be recrossed by the second guidewire704 by threading the guidewire704 through one of the relatively large inlet openings705 (FIG. 249), in a manner similar to that described previously with reference toFIG. 244.
• Referring to FIGS.252 to256 the position of thefilter1 in thevasculature21 may be controlled by anabutment200 on a guidewire201. By engaging theabutment200 with an abutment surface on thefilter1, thefilter1 is prevented from moving distally of theguidewire abutment200. In this manner, the position of thefilter1 in thevasculature21 may be controlled, if necessary.
• Theabutment200 may be fixedly attached to the guidewire201 by a suitable means, such as by crimping, before introducing the guidewire201 into thevasculature21. Alternatively theabutment200 may be fixed to the guidewire201 during deployment of thefilter1.
• As illustrated inFIG. 257 thefilter205 according to the invention may have atether206 fixed to thefilter205, extending proximally of thefilter205. Thetether206 may be used by a clinician to control the position of thefilter205 in thevasculature21 from a location externally of thevasculature21. Thetether206 may be in the form of a wire, and may be of any suitable material.
• In use, thefilter205 may be deployed over a guidewire207. If appropriate or necessary, the guidewire207 may then be withdrawn from thefilter205 and thevasculature21. Thetether wire206 may then be used as a platform for advancing further devices through thevasculature21, for example theretrieval catheter20.
• Referring to FIGS.258 to260, there is illustrated another embolic protection filter assembly115 according to the invention. The assembly115 comprises a filter and a receiver to guide theguidewire30 into theguidewire lumen12. The receiver is provided, in this case, by an approach channel116 for theguidewire30 in the form of a lumen in a separate catheter117. The catheter117 has one or more inflatable balloons118 at the distal end of the catheter117. The shape and/or position of the balloons118 is configured to ensure that the blood flow through thevasculature21 will not be occluded upon inflation of the balloon(s)118. In one case, the catheter117 has three balloons118 spaced circumferentially around the catheter117, as illustrated inFIG. 261. In another case, the catheter117 has four circumferentially spaced balloons118 (FIG. 262).
• In use, the catheter117 is introduced into thevasculature21 and advanced through thevasculature21 until the catheter distal end is proximally adjacent the filter1 (FIG. 56). The balloon118 is then inflated until the balloon118 engages the wall of thevasculature21. By engaging the balloon118 with the wall of thevasculature21 the catheter117 is spaced from the wall of thevasculature21 to assist in locating the catheter approach channel116 centrally in thevasculature21. Theguidewire30 may then be introduced into the channel116 and advanced through the catheter117. Because the channel116 is located centrally in thevasculature21, theguidewire30 is guided into theguidewire lumen12 of thefilter1 as it passes out of the distal end of the channel116. The balloon118 may be deflated to a low profile configuration during introduction and withdrawal of the catheter117 from thevasculature21.
• It will be appreciated that any number of seals may be provided to prevent embolic material passing through the guidewire lumen or the guidewire aperture, and the seals may be positioned at any suitable point along the guidewire lumen or the guidewire aperture.
• It will further be appreciated that the receiver may be configured to guide a docking device in the form of a coupling member, such as those described previously, towards the filter for coupling to the filter. In such a manner, the receiver may be used to assist retrieval of the filter. The coupling means may be achieved by numerous alternatives, for example male-female inter-engagement, or magnetic coupling, or hook and eyelet means.
• FIG. 263 illustrates anotherretrieval catheter600 according to the invention. The coupling member24, in this case, has atubular extension part601 which extends distally of thehooks100. In use, thetubular extension601 may be extended through an embolic protection filter602 to be retrieved, as illustrated inFIG. 264. Thetubular extension601 in this way defines the guidewire lumen603 through the filter602 through which a guidewire604 may be passed.
• Theretrieval catheter600 is particularly suitable for retrieving filters, such as the filter602 which do not have an inner tubular member to define a guidewire lumen through the filter602. Filters which do not have an inner tubular member are liable to becoming fixed against the guidewire604 when the filter is collapsed down. When this occurs it is no longer possible to retrieve the filter while the guidewire remains in situ in the vasculature.
• By defining the guidewire lumen603 using thetubular extension601 of theretrieval catheter600, this serves to isolate the collapsing filter602 from the guidewire604, and thus prevents the filter602 from becoming fixed to the guidewire604.
• Thetubular extension601 may be advanced to the distal end of the filter602 before retrieving the filter602 into the catheter body23, as illustrated inFIG. 85.
• Alternatively thetubular extension601 may be advanced until thetubular extension601 is distally of the distal end of the filter602 before retrieving the filter602 into the catheter body23.
• The invention is not limited to the embodiments hereinbefore described, with reference to the accompanying drawings, which may be varied in construction and detail.

Claims (10)

1. An embolic protection filter having an inlet end and an outlet end, the inlet end having one or more inlet openings sized to allow blood and embolic material enter the filter, and the outlet end of the filter having a plurality of outlet openings sized to allow through passage of blood but to retain undesired embolic material within the filter;

the filter having a guidewire aperture for passing the filter over a guidewire; and

the filter comprising a seal to seal the guidewire aperture.

2. A filter as claimed inclaim 1, wherein the seal is self-closing.

3. A filter as claimed inclaim 1, wherein the seal is located at a proximal end of the filter, and/or at a distal end of the filter.

4. A filter as claimed inclaim 1, wherein the filter has a tubular member extending from the guidewire aperture to define a guidewire lumen through the tubular member.

5. A filter as claimed inclaim 4, wherein the tubular member extends through at least part of the filter.

6. A filter as claimed inclaim 4, wherein the tubular member is radially offset from the longitudinal axis of the filter.

7. A filter as claimed inclaim 1, wherein the seal is an annular member around the guidewire aperture, the annular member being closable down to seal the guidewire aperture.

8. A filter as claimed inclaim 7, wherein the annular member is a tube

9. A filter as claimed inclaim 7, wherein the annular member comprises a soft membrane.

10. A filter as claimed inclaim 7, wherein the annular member comprises two or more circumferentially overlapping flaps.

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