Abstract:
A percutaneous transluminal temporary embolic protection device includes an embolic filter mounted to a guidewire shaft at a location proximate the distal end of the guidewire. The filter can be positioned down-stream from a thrombectomy treatment site at a target location and can be properly positioned to capture embolic particles that may be set loose into the blood stream as the thrombectomy procedure is performed. The embolic filter is normally undeployed against the guidewire shaft to facilitate introduction and withdrawal of the device to and from the target location

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present disclosure claims priority to U.S. Patent Application No. 62/005,226, filed Sep. 25, 2014, entitled “Temporary Embolic Protection Device and Methods Thereof,” which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    Implementations described herein relate generally to surgical devices and relate more specifically to temporary embolic protection devices and associated methods. 
         [0004]    2. Related Art 
         [0005]    Deep vein thrombosis (DVT) can be described as the formation of a blood clot or thrombus in a deep vein, predominately in the legs. Similarly, subclavian vein and axillary vein thrombosis (ASVT) are described as the formation of a blood clot or thrombosis in the subclavian vein or axillary veins between the clavicle and ribs. Pulmonary embolism is caused by the detachment or embolism of a clot that travels to the lungs. Together, DVT, ASVT and pulmonary embolism constitute a single disease process known as venous thromboembolism. Thrombectomy is a procedure used to break up clots and can be a percutaneous, catheter-based procedure. Percutaneous thrombectomy devices can be categorized as rotational, rheolytic or ultrasound enhanced. No matter the operational modality, distal embolism is a risk inherent to thrombectomy. Accordingly, a need exists for improved temporary embolic protection devices and associated methods. 
       SUMMARY 
       [0006]    It is to be understood that this summary is not an extensive overview of the disclosure. This summary is exemplary and not restrictive, and it is intended to neither identify key or critical elements of the disclosure nor delineate the scope thereof. The sole purpose of this summary is to explain and exemplify certain concepts of the disclosure as an introduction to the following complete and extensive detailed description. 
         [0007]    Stated generally, the present disclosure comprises a percutaneous transluminal temporary embolic filter and is intended for use as an adjunct to medical procedures where distal embolization is a risk. 
         [0008]    Stated more specifically, the present disclosure comprises a catheter having an elongated shaft, proximal and distal ends, a longitudinal axis and a filter. The filter comprises a first ring coaxially fixedly mounted on a distal portion of the catheter shaft, a second ring coaxially slidably mounted on a distal portion of the catheter shaft and configured to be moved toward and away from the first ring and a scaffolding extending between the first and second rings. The scaffolding further comprises a plurality of first longitudinal connecting members, each having a first end attached to the first ring and a second end extending toward the second ring; a plurality of second longitudinal connecting members, each having a first end attached to the second ring and a second end extending toward the first ring. The filter further comprises a membrane connected to at least the scaffolding. 
         [0009]    In an additional aspect, the present disclosure is directed to a wire-in-wire configuration including a guidewire and an embolic filter coupled to the guidewire. The embolic filter can include a first ring located proximate the distal end of the guidewire and a second ring located between the distal end of the guidewire and a proximal end of the guide wire. The filter can further include a filter membrane coupled to the first and second rings, where the filter membrane can be movable between an undeployed configuration and a deployed configuration upon displacement of the first and second rings relative to each other. The filter can also include an actuator wire extending through a central channel provided in the guidewire where the actuator wire is coupled to one of the first ring or the second ring such that activation of the wire results in a corresponding displacement of the first or second ring. The filter can further include a filter chasis or scaffolding comprising at least one strut extending between and coupled to the first ring and the second ring such that the strut bows outward from the guidewire, deploying the filter membrane, as a distance between the first and second ring decreases. 
         [0010]    In another aspect, the temporary embolic filter can comprise a wire-in-wire configuration comprising an outer wire having a lumen with an inner wire movably disposed therein. In this aspect, the filter is constructed substantially identically to the filter described above except that the distal-most first collar is located on a portion of the inner wire extending past the distal terminal end of the outer wire and the second collar is located on a distal portion of the outer wire. In operation, causing the inner wire to move proximally relative to the outer wire causes the filter to move from an undeployed configuration to a deployed configuration and vice-versa. 
         [0011]    Additional features and advantages of exemplary implementations of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary implementations as set forth hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects and together with the description, serve to explain the principles of the methods and systems. 
           [0013]      FIG. 1  illustrates a side view of one aspect of a temporary embolic filter. 
           [0014]      FIG. 2A  illustrates a cross-section of the proximal end of the device with integral embolic filter shown in  FIG. 1 ; and  FIG. 2B  illustrates a cross-section of the distal end of the device shown in  FIG. 1 . 
           [0015]      FIG. 3A  illustrates a schematic view of one aspect of a filter scaffolding of the embolic filter device of  FIG. 1 , showing the filter scaffolding in an un-deployed position. 
           [0016]      FIG. 3B  illustrates a schematic view of the filter scaffolding of  FIG. 3A , showing the filter scaffolding in a deployed position. 
           [0017]      FIG. 4A  illustrates a schematic view of one aspect of a filter scaffolding of the embolic filter device of  FIG. 1 , showing the filter scaffolding in an un-deployed position. 
           [0018]      FIG. 4B  illustrates a schematic view of the filter scaffolding of  FIG. 4A , showing the filter scaffolding in a deployed position. 
           [0019]      FIG. 5  illustrates a schematic view of another aspect of a filter scaffolding of the embolic filter device of  FIG. 1 , showing the filter scaffolding in an un-deployed position. 
           [0020]      FIG. 6  illustrates a schematic view of the filter scaffolding of  FIG. 5 , showing the filter scaffolding in a deployed position. 
           [0021]      FIG. 7  illustrates a schematic view of a third aspect of a filter scaffolding of the embolic filter device of  FIG. 1 , showing the filter scaffolding in an un-deployed position. 
           [0022]      FIG. 8  illustrates a schematic view of the filter scaffolding of  FIG. 7 , showing the filter scaffolding in a deployed position. 
           [0023]      FIG. 9  illustrates another embodiment of a temporary vascular filter having a wire-on-wire configuration. 
           [0024]      FIG. 10A  illustrates another example of an embolic filter including an outer sleeve. 
           [0025]      FIG. 10B  illustrates another view of the embolic filter of  FIG. 4A . 
           [0026]      FIG. 11  illustrates a blood vessel having a stenosis. 
           [0027]      FIG. 12  illustrates the blood vessel with stenosis of  FIG. 11  with the embolic filter device of  FIG. 1  positioned therein. 
           [0028]      FIG. 13  illustrates the blood vessel and embolic filter device of  FIG. 11  with the integral embolic filter expanded. 
           [0029]      FIG. 14  illustrates the blood vessel and embolic filter device of  FIG. 11  with the integral embolic filter deployed. 
           [0030]      FIG. 15  illustrates the blood vessel and device of  FIG. 11  after treatment of the stenosis, with the embolic filter still in its deployed position. 
           [0031]      FIG. 16  illustrates the blood vessel and device of  FIG. 11  after treatment of the stenosis, with the embolic filter in an un-deployed position in preparation for withdrawal of the device from the vessel. 
           [0032]      FIG. 17  illustrates an alternate aspect of a filter scaffolding comprising a sinusoidal frame. 
           [0033]      FIG. 18  illustrates one aspect of the attachment of the sinusoidal frame. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    The present invention can be understood more readily by reference to the following detailed description, examples, drawing, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. 
         [0035]    The following description of the invention provided as an enabling teaching of the invention in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results described herein. It will also be apparent that some of the desired benefits described herein can be obtained by selecting some of the features described herein without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part described herein. Thus, the following description is provided as illustrative of the principles described herein and not in limitation thereof. 
         [0036]    Reference will be made to the drawings to describe various aspects of one or more implementations of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of one or more implementations, and are not limiting of the present disclosure. Moreover, while various drawings are provided at a scale that is considered functional for one or more implementations, the drawings are not necessarily drawn to scale for all contemplated implementations. The drawings thus represent an exemplary scale, but no inference should be drawn from the drawings as to any required scale. 
         [0037]    In the following description, numerous specific details are set forth in order to provide a thorough understanding described herein. It will be obvious, however, to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known aspects of percutaneous transluminal devices and embolic filters have not been described in particular detail in order to avoid unnecessarily obscuring aspects of the disclosed implementations. 
         [0038]    As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. 
         [0039]    “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. 
         [0040]    Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes. 
         [0041]    Referring now to the drawings, in which identical numbers indicate identical elements throughout the various views,  FIG. 1  illustrates a first aspect of a catheter with integral embolic filter  10  according to the present invention. The catheter with integral embolic filter  10  comprises an elongated catheter  12  having a shaft  14  with a proximal end  16  and a distal end  18 . As used herein, “proximal” refers to the portion of the device closest to the physician performing the procedure and “distal” refers to the portion of the device that is furthest from the physician performing the procedure. The shaft  14  of the catheter  12  is sized and configured to slidably receive a thrombectomy treatment device (e.g., an angioplasty balloon, a mechanical thrombosis device, an ablation device, or any other tool or surgical device known in the art for treatment of thrombosis). As illustrated in the figures, and in contrast to previous treatment catheter, the shaft  14  of the catheter  12  does not include any integrated treatment features, e.g., an angioplasty balloon coupled to/extending from the shaft of the catheter to treat the thrombosis. Instead, the shaft  14  of the present catheter  12  is sized to accommodate a treatment device slidable along the shaft  14 . Thus allowing the catheter  12  to guide the treatment device to the target location. The use of a slidable and detachable treatment device also allows for a greater variety of thrombectomy treatment devices as the system is no longer limited to the catheter&#39;s treatment modality (e.g., catheter with an integral angioplasty balloon where the balloon and/or inflation port of the balloon could block access/movement of the device along the catheter shaft). 
         [0042]    An embolic filter  30  can be mounted to the catheter shaft  14  at or proximal to the distal end  18  of the catheter  12 . In additional or alternative embodiments, the filter  30  can be oriented to face towards or away from the treatment device. One skilled in the art will also appreciate in light of the present disclosure that the catheter can be configured to be, for example and without limitation, an over-the-wire catheter, a rapid-exchange catheter and the like. It is solely for clarity of disclosure that the present description describes an over-the-wire catheter modality. 
         [0043]    Referring now to  FIG. 2 , the catheter shaft  14  can define two lumens: a main lumen  32  and an embolic filter actuator wire lumen  36 . The main lumen  32  can extend from the proximal end  16  to the distal end  18  of the catheter shaft  14 . The main lumen  32  can optionally provide a working channel and be configured to receive a guidewire therethrough for advancing the distal end  18  of the catheter  12  through the patient&#39;s vasculature to a target location. As used herein, the term “target location” refers to a location downstream to the occlusion within the patient&#39;s vasculature being treated. The actuator wire lumen  36  can extend from a proximal port  44  at the proximal end  16  of the catheter  12  and through the catheter shaft  14  to a distal port  46 . 
         [0044]    Referring to aspects of the present disclosure illustrated in at least  FIGS. 3A through 4B , the embolic filter  30  comprises a filter membrane  50  having holes selectively sized to permit the passage of blood but to capture particles larger than normal blood particles and a filter chassis or scaffolding  52 , for supporting the filter membrane. For clarity of illustration, many of the drawing figures omit the filter membrane  50  when illustrating the filter chassis or scaffolding, but it will be understood that all embolic filters disclosed in this application comprise a filter membrane supported by the filter chassis or scaffolding. It is contemplated that the chassis or scaffolding  52  can include a proximal ring  56  and a distal ring  54 . In operation, movement of the proximal ring  56  toward and away from the distal ring  54  to open and to close the embolic filter  30  can be accomplished by manipulation of an actuator wire  84 . In one aspect, the proximal end  86  of the actuator wire  84  can extend out of the proximal port  44  of the actuator wire lumen  36  so as to be controllable by the physician performing the procedure. Here, the actuator wire  84  can extend through the actuator wire lumen  36  and can exit through the distal port  46  of the actuator wire lumen. It is contemplated that the distal end  88  of the actuator wire  84  can be attached to at least one of the distal ring  54  or the proximal ring  56 . 
         [0045]    In one aspect, the distal ring  54  can be fixed in place on the catheter shaft  14 , and the proximal ring  56  can be slidably mounted to the catheter shaft for axial movement in the proximal and distal directions. In another aspect, the proximal ring  56  can be fixed in place on the catheter shaft  14 , and the distal ring  54  can be slidably mounted to the catheter shaft for axial movement in the proximal and distal directions. 
         [0046]    In one aspect illustrated in  FIGS. 3A and 3B , the filter chassis  52  comprises a plurality of ribs or struts  80  spaced circumferentially about and connected to the proximal and distal rings,  56  and  54 , respectively, each strut having a first end and a second end. The first end of each strut  80  can be attached to the distal ring  54  and the second end of each strut can be attached to the proximal ring  56 . In operation, when the relative distance between the distal ring and proximal ring decreases, the struts  80  will bow outward, erecting the filter membrane  50  as shown in  FIG. 3B . In one exemplary aspect, the distal port  46  of the actuator wire lumen  36  is located between the proximal ring  56  and the distal ring  54 . Here, the proximal ring is fixed relative to the catheter and the distal ring, which is operably coupled to the actuator wire, is movable along the axis of the catheter. In operation, the actuator wire would be pulled proximally  58  to move the distal ring towards the proximal ring, causing the struts to bow outward and move the filter from an undeployed position to a deployed position. 
         [0047]    In another aspect illustrated in  FIGS. 4A and 4B , the filter chassis or membrane can comprise a plurality of struts  80  that further comprise a plurality of first strut sections  60  and a plurality of second strut sections  70 . Each of the plurality of first strut sections  60  can have a first end  62  and a second end  64 . The first end  62  of each first strut section  60  can be attached to the distal ring  54 , and each first strut section can extend in the proximal direction. Each of a corresponding plurality of second strut sections  70  can have a first end  72  and a second end  74 . Here, the first end  72  of each second strut section  70  can be attached to the proximal ring  56 , and each second strut section can also extend in the proximal direction. The second end  64  of each first strut section  60  can attach to the second end  74  of a corresponding second strut section  70 . As one skilled in the art will appreciate, a plurality of strut  80  can be spaced circumferentially about and connecting the proximal and distal rings to form the scaffolding  52 . In operation and as shown in  FIGS. 4A and 4B , when the proximal and distal rings  56 ,  54  are adjacent one another each strut  80  can be configured to fold back upon itself. Additionally, when the proximal ring  56  is proximally displaced from the distal ring  54 , the struts  80  can be configured to open in a manner similar to an umbrella. The filter membrane  50  can be supported on the first strut sections  60  such that when the scaffolding  52  opens, as shown in  FIG. 4B , the filter membrane can deploy in a manner similar to an umbrella canopy. In contrast to the embolic filter  30  depicted in  FIG. 3B , the deployed filter depicted in  FIG. 4B  (and  FIGS. 6 ,  8  and  10 ) defines an arrow-shaped profile. That is, the filter membrane  50 , extends along both the first and second strut sections  60 ,  70  at an acute angle with respect to the shaft  14 . This structure prevents material captured by the embolic filter  30  from being released when the embolic filter  30  is removed from the patient. For example, particles can be trapped by the filter membrane  50  extending along the first strut  60 , second strut  70  and/or the shaft  14  of the catheter. 
         [0048]    In yet other aspects, the plurality of second strut sections  70  can be replaced with a sinusoidal ring structure  55  as illustrated in  FIGS. 17-18 . In this aspect, the sinusoidal ring  55  contracts radially inward as the relative distance between the distal and proximal rings increases and expands as the relative distance between the distal and proximal rings decreases. 
         [0049]    It is contemplated that each strut can further comprise at least one “zone of weakness,” i.e., a zone of the strut that can be configured to be physically weaker than the majority of the strut in order to control the locations at which the struts bend. One skilled in the art will appreciate that the at least one zone of weakness can be formed in any of a number of ways. In one aspect, a notch can be formed in one or both sides of the strut. In another aspect, at least one of the upper surface and lower surface of the strut can be scored. In another aspect, the at least one zone of weakness can be formed of a material that can be structurally weaker than the material comprising the remainder of the strut. In yet other aspects, the at least one zone of weakness can comprise mechanical hinges. In yet other aspects and as shown in  FIG. 15 , the apices of the sinusoidal ring  55  comprise a zone of weakness. In even further aspects, at least two of these approaches can be combined to form the at least one zone of weakness, e.g., both notching the width and scoring the depth of the strut. In addition, the at least one zone of weakness can comprise a plurality of one type of physical arrangement, e.g., a single zone of weakness can comprise a plurality of notches or a plurality of scores. In operation, the at least one zone of weakness can be configured to bend the strut in response to a force at a predetermined angle to the longitudinal axis of that portion of the strut. 
         [0050]    One skilled in the art will appreciate here are a variety of ways in which the filter scaffolding  52  and actuator wire  84  can be arranged to permit the embolic filter  30  to be opened and closed by moving the proximal end  86  of the actuator wire. In a first aspect, the filter scaffolding  52  can be formed in a normally closed or undeployed position. In operation, pulling the proximal end  86  of the actuator wire  84  can cause the proximal ring  56  to slide in a proximal direction to open the filter scaffolding  52 . The filter scaffolding can be configured so that releasing the tension on the actuator wire  84  and/or pushing the actuator wire  84  distally can permit the filter scaffolding  52  to collapse to an un-deployed position. 
         [0051]    In another aspect of the present disclosure illustrated in  FIGS. 5 and 6 , a filter scaffolding  152  can comprise a proximal ring  156  that can be fixed with respect to a catheter shaft  114  and a distal ring  154  that can be slidably positioned along the catheter shaft in the proximal and distal directions. In a further aspect, a distal port  146  of an actuator wire lumen  136  can be located distal to the proximal ring  156 . Here, an actuator wire (not shown) can extend through the actuator wire lumen, can exit through a distal port  146 , and can attach to the distal ring  154 . The filter scaffolding  152  can be formed in a normally closed position. In operation, pushing the actuator wire  184  can displace the distal ring  154  in a distal direction away from the proximal ring  156  to deploy the filter scaffolding  152 . The filter scaffolding can be configured so that releasing the force on the actuator wire  184  and/or pushing the actuator wire  184  distally can permit the filter scaffolding  152  to return to its un-deployed position. 
         [0052]    In yet another aspect of the present disclosure illustrated in  FIGS. 7 and 8 , a proximal ring  254  can be fixed with respect to a catheter shaft  214 , and a distal ring  256  can be slidably positioned along the catheter shaft in the proximal and distal directions. In a further aspect, a distal port  246  of an actuator wire lumen  236  can be located distal to the distal ring  256 . Here, an actuator wire  284  can extend through the actuator wire lumen  236 , can exit through the distal port  246 , and can attach to the distal ring  256 . As illustrated in  FIGS. 4-8 , the distal port  46 ,  146 ,  246  can be located offset from the distal end of the catheter shaft  14 ,  114 ,  214 . Accordingly, the actuator wire lumen  36 ,  146 ,  246  can terminate before the distal end of the catheter shaft  14 ,  114 ,  216  thereby providing a solid nose portion extending distally from the termination of the actuator wire lumen  36  and/or the distal port  46 ,  146 ,  246 . 
         [0053]    The filter scaffolding  252  can be formed in a normally closed position. In operation, pulling on the actuator wire  284  can displace the distal ring  256  in a distal direction and away from the proximal ring  156  to deploy the filter scaffolding  252 . The filter scaffolding can be configured so that releasing the force on the actuator wire  284  can permit the filter scaffolding  252  to return to its un-deployed position. 
         [0054]    Referring back to  FIGS. 4A and 4B , another aspect of a filter scaffolding can be structurally identical to the first embodiment  52  except that the filter scaffolding can be formed in a normally open or deployed position. Here, it is contemplated that application of a distally directed force to the proximal end  86  of the actuator wire  84  (i.e., pushing the actuator wire) can maintain the proximal ring  56  in its distal position and hence can maintain the filter scaffolding  52  in its un-deployed position. The filter scaffolding  52  can be permitted to expand to its normally deployed position, expanding the filter membrane  50 , upon release of the force applied to the actuator wire  84 . Immediately after completion of the interventional procedure, a distally directed force can again be applied to the proximal end  86  of the actuator wire  84 , moving the proximal ring  56  toward the distal ring  54  and collapsing the filter scaffolding  52 . 
         [0055]    Referring back to  FIGS. 5 and 6 , a fifth aspect can be structurally identical to the third aspect with the exception that the filter scaffolding  152  can be formed in a normally open position. Here, it is contemplated that the distal ring  154  can be normally displaced toward the distal end  18  of the catheter shaft  114 . In operation, pulling on the distal end  188  of the actuator wire  184  can move the distal ring  154  proximally toward the fixed proximal ring  156 , collapsing the filter scaffolding  152  while releasing the tension on the actuator wire  184  can permit the filter scaffolding  152  to expand to its deployed position. 
         [0056]    While  FIGS. 1-8  are described above as illustrating a catheter including an integral embolic filter  10 , it is contemplated that the catheter could be replaced by a guidewire such that the apparatus would comprise a wire-in-wire configuration, i.e., a guidewire including an integral embolic filter, and an actuator wire extending within a central lumen of the guidewire. Accordingly, without repeating the description of each of  FIGS. 1-8  as provided above, it is contemplated that each of those figures are also illustrative of a guidewire including an integral embolic filter  10 . Each of the additional elements described above are considered the same. For example, the system illustrated in  FIGS. 3A and 3B  can include an embolic filter  30  comprising a filter membrane  50  having holes selectively sized to permit the passage of blood but to capture particles larger than normal blood particles and a filter chassis or scaffolding  52 , for supporting the filter membrane. The chassis/scaffolding  52  can include a proximal ring  56  and a distal ring  54 . In operation, movement of the proximal ring  56  toward and away from the distal ring  54  to open and to close the embolic filter  30  can be accomplished by manipulation of an actuator wire  84 . In one aspect, the proximal end  86  of the actuator wire  84  can extend out of the proximal port  44  of the actuator wire lumen  36  provided on the guidewire, such that the actuator wire  36  is controllable by the physician performing the procedure. The actuator wire  84  can extend through the actuator wire lumen  36  and can exit through the distal port  46  of the actuator wire lumen. The distal end  88  of the actuator wire  84  can be attached to at least one of the distal ring  54  or the proximal ring  56 . The distal ring  54  can be fixed in place on the catheter shaft  14 , and the proximal ring  56  can be slidably mounted to the catheter shaft for axial movement in the proximal and distal directions. Alternatively, the proximal ring  56  can be fixed in place on the catheter shaft  14 , and the distal ring  54  can be slidably mounted to the catheter shaft for axial movement in the proximal and distal directions. 
         [0057]    In general, a guidewire is constructed from a smaller (diameter) and more rigid material than a catheter. Similar to catheters, guidewires provide torque control, flexibility and the ability to support the passage of another device or system over it. Due to their structure, guidewires generally provide better trackability (ability navigate vasculature) and steerability. 
         [0058]    As will be described below, because a guidewire has a smaller outer diameter than a catheter, a greater variety of thrombectomy tools and treatment devices and be provided over the guidewire to access the treatment position. The tool/treatment device may be movable over the guidewire in multiple directions over guidewire, i.e., axially along the guidewire toward/away from the distal end of the guidewire, rotationally around the diameter of the guidewire. The thrombectomy tool/treatment device can include an angioplasty balloon, a mechanical thrombosis device, an ablation device, or any other tool or surgical device known in the art for treatment of thrombosis. 
         [0059]    The increased sized (diameter) of the catheter can increase the possibility of ostial trauma and vascular complications. For vascular treatment, catheter diameters generally range from 4 F to 25 F (outer diameter ranging from 0.055 inches to 0.345 inches), selection depending various factors including the age of the patient and the size of the vessels. In contrast, for vascular treatment, guidewire diameters generally range from 0.010 inches to 0.060 inches. Typically, a physician will choose the smallest diameter catheter feasible to minimize the risk of trauma or complications during the procedure. In contrast, because guidewires have a much smaller diameter than catheters, the diameter of the guidewire is a less significant factor in selection. Instead, selection is guided by vessel anatomy, devices to be used/passed over the guidewire, and physician preference. In the present system, it is contemplated that the guidewire can have an outer diameter between 0.010 inches to 0.060 inches. In another example, the outer diameter can vary between 0.012 inches and 0.045 inches. In yet another example, the outer diameter can vary between 0.014 inches and 0.035 inches. 
         [0060]    A catheter is generally described as a hollow flexible tube that is inserted into the body, duct or vessel over a guidewire. The flexibility of a catheter typically necessitates the use of a guidewire. In the present example, because the embolic filter is integral with the guidewire, the system does not require an additional guidewire or other guiding device to direct movement and location of the filter. The flexibility/stiffness of a catheter or a guidewire defines the characteristics of the wire a measure of its elastic modulus and can be measured in terms of its flexural modulus. Flexibility/stiffness varies, for example, in relation to the material properties, core diameter, and physical structure of the catheter/guidewire. The stiffness of a catheter used in vascular treatment ranges from 3.0 g to 50.0 g. In contrast, stiffness of a guidewire used in vascular treatment can range from 1.5 g to 14.0 g. For example, polymer-covered (hydrophilic) wires such as an Abbott HT Pilot® 50 guidewire can have a stiffness of 1.5 g. An Abbott HT Pilot® 150 and 200 can have a stiffness of 2.7 g and 4.1 g, respectively. An Abbott HT Progress® 40, 80, 120 can have a stiffness of 4.8 g, 9.7 g, 13.9 g, respectively. A Boston Scientific Choice PT® can have a stiffness of 1.9 g. Non-covered (non-lubricious) coil guide wires, such as Abbott HT Cross-IT® 100XT can have a stiffness of 1.7 g. An Abbott Miraclebros® can have various stiffness, including, 3.9 g, 4.4 g, 8.8 g, and 13.0 g. A Confianza Pro® can have a stiffness of 9.3 g and 12.4 g. And a Medtronic Persuader® 3, 6 can have a stiffness of 5.1 and 8.0, respectively. Similarly, the flexural modulus of a guidewire used in vascular treatment can range from 9.5 Gpa to 158.4 Gpa. For example, a plain Amplatz type wire has a stiffness of 9.5 GPa. A “heavy duty” Amplantz type wire has a stiffness ranging from 11.4 GPA to 14.5 GPa. A “stiff” Amplantz type wire has a stiffness of 17 GPa. An “extra stiff” Amplantz type wire has a stiffness of 29.2 GPa. A “super stiff” Amplantz type wire has a stiffness of 60.3 GPa. An “ultra stiff” Amplantz type wire has a stiffness of 65.4 GPa. A Backup Meier® wire has a stiffness of 139.6 GPa. A Lunderquist® “extra stiff” wire has a stiffness of 158.4 GPa. 
         [0061]    In another aspect illustrated in  FIG. 9 , the temporary embolic filter  100  can comprise a wire-in-wire configuration comprising an outer wire  102  having a lumen  104  with an inner wire  106  movably disposed therein. In this aspect, the filter  106  is constructed substantially identically to the filter described above except that the distal-most first collar  108  is located on a portion of the inner wire extending past the distal terminal end of the outer wire and the second collar  110  is located on a distal portion of the outer wire. In operation, causing the outer wire to move proximally relative to the inner wire causes the filter to move from an undeployed configuration to a deployed configuration and vice-versa. 
         [0062]    In another aspect it may be desirable for the embolic filter and corresponding catheter/guidewire to remain in the patient for an extended period of time, e.g., more than just temporary placement/treatment. Accordingly a catheter/guidewire may be provided with an outer sleeve that permits longer term placement within the patient.  FIGS. 10A and 10B  illustrate a guidewire with integral embolic filter  300  including an outer sleeve  390 . The outer sleeve  390  extends over the guidewire  312  and provides a protective barrier between the guidewire  312  and the patient. 
         [0063]    The guidewire with integral embolic filter  300  can include similar components and structure to those described above with respect to the catheters/guidewires illustrated in  FIGS. 1-9 . For example, similar to the catheters/guidewires depicted in in  FIGS. 1-9 , guidewire with integral embolic filter  300  provided in  FIGS. 10A and 10B  can comprise an elongated guidewire  312  having a shaft  314  with a proximal end  316  and a distal end  318 . The embolic filter  330  can be mounted on the guidewire shaft  314  at proximate the distal end  318  of the guidewire  312 . Because the embolic filter  330  is coupled directly to the guidewire  312 , the guidewire  312  can be advanced through the patient&#39;s vasculature to a target location without the assistance of an additional locating guidewire. The guidewire  312  can be composed of a highly trackable and steerable material such as nitinol. 
         [0064]    As outlined above, the embolic filter  330  comprises a filter membrane  350  and a filter chassis or scaffolding  352 , for supporting the membrane. The chassis/scaffolding  352  can include a proximal ring  356  and a distal ring  354 . In operation, movement of the proximal ring  356  toward and away from the distal ring  354  cause the embolic filter  330  to open and close. Either the distal ring  354  or the proximal ring  356  can be fixed to the guidewire shaft  314 , with the other ring sildably mounted to the guidewire shaft  314  for axial movement in the proximal and distal directions. As provided above, the chassis/scaffolding  352  can include a plurality of rips or struts (and/or a plurality of strut sections) spaced circumferentially around the guidewire  312  and coupled to the proximal and distal rings  356 , 354 . Each strut can further comprise a “zone of weakness” to control the locations at which the struts bend. The plurality of strut section can also be replaced with a sinusoidal ring structure as illustrated in  FIGS. 17-18 . 
         [0065]    In operation, movement of the proximal ring  56 /distal ring  354  toward and away from each other can be accomplished by manipulation of an actuator wire  384 . The guidewire  312  can include an actuator wire lumen  336  that extends from the proximal end  316  to a location proximate the distal end  318  of the guidewire  312 . The actuator wire lumen  336  can extend from a proximal port  344  at the proximal end  316  of the guidewire  312 , through the guidewire shaft  314 , to a distal port  346 . The actuator wire  384  can be accessed at the distal port  346  such that the wire can be moved in the proximal and distal directions. As illustrated in  FIG. 10B , the actuator wire  384  can be coupled to an actuator screw  392  located near the proximal port  344 . Rotation of the actuator screw  392  can result in corresponding axial movement of the actuator wire  384  in the proximal and distal directions. It is also contemplated that the actuator wire  384  can be manipulated without the use of an actuator screw  392 . For example, access to the wire is provided at the distal port  346  where the actuator wire  384  is manipulated either directly or via the use of a tool. As illustrated in  FIG. 10B , the outer sleeve can be include an end cap  396  for sealing the opening provided at the end of the outer sleeve  309 . If an actuator screw  392  is not utilized, the actuator wire  384  can be fixed to the end cap such that its proximal/distal location is fixed with the end cap is in closed position. 
         [0066]    As illustrated in  FIG. 10A , the distal port  346  is located between the proximal ring  356  and the distal ring  354 . Here, the proximal ring  356  is fixed relative to the guidewire  312  and the distal ring  354 . The actuator wire  384 , extending through the actuator wire lumen  336  is operably coupled to the distal ring  354 , which is movable along the axis of the guidewire  312 . In operation, the actuator wire  384  is pulled proximately to move the distal ring  354  towards the proximal ring  356 , causing the embolic filter  330  to bow outward and move from an undeployed position to a deployed position. In another example, not illustrated, the actuator wire  384  is operably coupled to the proximal ring  356 , which is movable along the axis of the guidewire  312 . In operation, the actuator wire  384  is pulled proximately to move the proximate ring  356  towards the distal ring  354 , causing the embolic filter  330  to bow outward and move from an undeployed position to a deployed position. 
         [0067]    As illustrated in  FIG. 10A , the distal port  346  is located proximate the distal end  318  of the guidewire  312 . It is further contemplated that the distal port  346  for the actuator wire  384  can be located at any position along the guidewire  312 . For example, the distal port  346  can be located at the extreme distal end of the guidewire  312  or at a position between the proximal end  316  and the proximal ring  356 . As provided in  FIG. 10A , the guidewire  312  includes a reduced diameter portion  394  adjacent the distal end  318 . The actuator wire lumen  336  can extend through the reduced diameter portion  394  or, as illustrated in  FIG. 10A , the actuator wire lumen  336  can extend only through the increased diameter portion with the distal port  346  located on a surface of the increased diameter portion of the guidewire  312 . The reduced diameter portion  394  can provide a solid nose portion of the guidewire  312  to assist in navigating the guidewire  312  to the target location. 
         [0068]    As illustrated in  FIGS. 10A and 10B , the guidewire with integral embolic filter  300  includes an outer sleeve  390 . The outer sleeve  390  extends over the guidewire  312  and provides a protective barrier between the guidewire  312  and the patient. Use of the outer sleeve  390  permits long-term/indefinite placement of the filter  300  within the patient. The outer sleeve  390  can be configured to permit relative movement between the outer sleeve  390  and the guidewire  312  such that the expanded filter  330  can remain stationary within the patient, despite movement of the patient and/or outer sleeve  390  with respect to the guidewire  312 . For example, outer sleeve  390  can be constructed from a semi-rigid material and low friction material including, for example, a plastic or metal material such as stainless steel, nitinol, polyolefins, polyesters, polyurethanes, florinated polymers, or any other material known in the art, The outer sleeve  390  can be constructed from a low friction material and/or include a coating that permits relative movement between the outer sleeve  390 , the guidewire  312  and the patient. For example, the outer sleeve  390  can have a polytetrafluoroethylene (PTFE), polyethylene furanoate (PEF), or hydrophilic coating. The outer sleeve  390  can also be sized to permit relative movement between the outer sleeve  390 , the guidewire  312 , and the patient. For example, the outer sleeve  390  can have an inner diameter greater than the outer diameter of the guidewire  312 . In one example, the outer sleeve  390  can have an outer diameter of 0.035 inches, an inner diameter of 0.029 inches, with a resulting wall thickness of 0.003 inches. The guidewire  312  can have an outer diameter of 0.027 inches, providing a 0.001 clearance around the perimeter of the guidewire  312 . The example guidewire  312  can also have an inner diameter of 0.013 inches, with a resulting wall thickness of 0.007 inches. 
         [0069]    As outlined above, it is contemplated that various thrombectomy tools/treatment devices can be movable (in multiple directions) over the guidewire  312 . Likewise, because the combined outer sleeve  390  and guidewire  312  has an outer diameter smaller than a catheter, it is contemplated that various thrombectomy tools/treatment devices can be provided over the combined sleeve  390 /guidewire  312 . 
         [0070]    In yet another aspect, the temporary embolic filter can have a braided nitinol scaffold and, in a further aspect, the scaffold can be configured with a baseline memory in the undeployed configuration. The scaffold can be coupled to a membrane comprising a finely-brained nitinol wire and, in a further aspect, the membrane can be coupled to the inner surface of the scaffold. In a further aspect, the membrane can have a baseline memory in the deployed configuration. In operation, when the scaffold is activated and deployed by the operator, the filter membrane will urge towards its baseline, deployed configuration but will be controllably constrained by the scaffold. 
         [0071]    In those aspects in which the force applied to the actuator wire is configured to be an axial compressive force, those skilled in the art can appreciate that a stiffer wire can be used to prevent buckling of the actuator wire than in those embodiments where the force applied to the actuator wire is configured to be an axial tensile force. 
         [0072]    In the present disclosure, and especially in the case of actuator wires, the term “wire” is intended to comprise, for example and without limitation, metallic wires, polymeric wires, and the like. In the case of polymeric wires, the polymers used can comprise, for example and without limitation, nylon, polypropylene and the like. 
         [0073]    In the foregoing aspects, the filter chassis or scaffold can be formed from any material known to be suitable, including shape-memory materials such as, for example and without limitation, nitinol. It is also contemplated that the scaffold components can be laser cut, formed from braided elements or any other method known in the art. 
         [0074]    In the foregoing aspects, the filter membrane  50  can be formed from at least one of a textile, a polymer and a wire mesh or braid. In one non-limiting aspect, the filter membrane can be formed from braided nitinol wire and, in a further aspect, can have a baseline shape corresponding to either a deployed or undeployed configuration. In another aspect, the filter membrane  50  comprises pores and, in a further aspect, the pores can be sized to allow blood to pass but not embolic particles. It is also contemplated that the filter membrane  50  can be mounted either on top of or inside of the frame. It is contemplated that the filter membrane  50  and chassis/scaffolding can have a deployed diameter up to 50 mm or approximately 2 inches. 
         [0075]    In the foregoing aspects, the filter membrane  50  can be configured to cover the exterior surface of the outermost strut sections, i.e., the first strut sections  60 ,  160 , and  260 . Optionally, the filter membrane  50  can be further configured to extend beyond the distal or second ends  64 ,  164 , and  264 ,  364  of the first strut sections  60 ,  160 , and  260 , where it can be attached to the circumference of the distal ring  54 ,  154 ,  254 . In those aspects in which the distal ring can be fixed, the filter membrane  50  can optionally be configured to extend beyond the distal end of the distal ring and can be attached to the circumference of the catheter/guidewire shaft  14 ,  114 ,  314  at a location between the distal ring  54 ,  154 ,  254  and the distal end of the catheter/guidewire shaft. 
         [0076]    It is also contemplated that the filter membrane  50  in each of the disclosed embodiments can be attached to the inner surfaces of the first strut sections  60 ,  160 , and  260  instead of to the outer surfaces. 
         [0077]    It is further contemplated that the inner or second strut sections  70 ,  170 ,  270  can also be configured in a concave shape with respect to the blood flow when the filter scaffolding is deployed. In further or additional aspects, the filter membrane  50  can be attached to the inner or outer surfaces of the second strut sections  70 ,  170 ,  270 . When the filter membrane  50  is attached to the surfaces of the second strut sections  70 ,  170 ,  270 , the filter membrane  50  can optionally extend beyond the distal or second ends  74 ,  174 ,  274  of the second strut sections and be attached to the circumference of the proximal ring  56 ,  156 ,  256 ,  356 . It is also contemplated that, if the filter membrane  50  can be attached to the outer surfaces of the second strut sections  70  and the proximal ring  56 ,  156 ,  256 ,  356  can be fixed, the filter membrane can be configured to extend beyond the distal end of the proximal ring and can be attached to the catheter shaft  14  at a location between the proximal and distal rings  56 ,  54 . 
         [0078]    In all of the foregoing instances, the filter scaffolding comprises a fixed ring and a movable ring, raising the filter can be accomplished by moving the rings apart, and collapsing the filter can be achieved by moving the rings together or vice-versa. “Moving apart” and “moving together” are used as relative terms, such that only one of the two rings need move with respect to the other ring for the rings to “move apart” or “move together.” 
         [0079]    Similarly, the process of raising and collapsing the filter can be thought of as being viewed from the perspective of the catheter, such that a movable ring can be moved toward or away from a fixed ring. 
         [0080]    In all of the foregoing instances, one can appreciate that both actively applying a force to move a ring and releasing a force to permit the ring to move of its own accord comprise a step of “causing” the movable ring to move by “controlling” the actuator wire. Thus, in both the normally deployed and normally un-deployed filter scaffolding embodiments described herein, the actuator wire can be “controlled” to “cause” a movable ring to move, whether that control takes the form of applying or releasing a force on the actuator wire. 
         [0081]    It is also contemplated that, rather than having the physician directly grasp the proximal end of the actuator wire, a control device can be associated with the proximal end of the actuator wire at the proximal end of the catheter shaft. The control device can incorporate, for example and without limitation, levers, sliders, rotating spindles, or the like to facilitate movement of the wire. One example of such a mechanical arrangement is described in U.S. Patent Publication No. US 2010/0106182, paragraphs [0079]-[0090] and FIGS. 29-33, which disclosure is hereby incorporated by reference. 
         [0082]    Use of the temporary embolic filter described above to prevent an embolism in a blood vessel can be shown in  FIGS. 11-15 . In  FIG. 11 , a vessel  500  can have a branch vessel  502  diverging from it. The vessel  500  can have a stenosis  504 . The direction of blood flow through the vessel  500  is indicated by the arrow  506 . A guide wire  508  can be inserted by the physician as a preliminary step in the interventional procedure when using a catheter with integral embolic filter (as noted above, an introductory guidewire is not necessary when a guidewire with integral embolic filter is used). 
         [0083]      FIG. 12  shows the catheter/guidewire  12  with embolic filter  30  in its un-deployed position and lying adjacent to the catheter/guidewire shaft  14 . The distal end  18  of the catheter  14  has been advanced over the guide wire  506  until the un-deployed embolic filter is at the target location. Similarly, the distal end  18  of the guidewire shaft  14  can be advanced through the vessel  500  until the un-deployed embolic filter is at the target location. 
         [0084]    In  FIG. 13  the embolic filter  30  has been expanded by pulling on the actuator wire  84 . In  FIG. 14 , a thrombectomy device  20  is deployed. (For the sake of clarity of the present invention, the thrombectomy device is only abstractly represented.) In the process of thrombectomy, embolic particles  510  are released and swept by the blood flow into the open proximal end of the embolic filter  30 , where they are captured by the filter membrane  50 . 
         [0085]    In  FIG. 15 , the formerly stenosed region can be open, and the thrombectomy device is removed. The embolic filter  30  remains open to capture any emboli released as the thrombectomy device is removed. 
         [0086]    In  FIG. 16 , the embolic filter  30  can be closed, trapping captured emboli within the filter. The catheter  12  can now be withdrawn from the vessel  500 . 
         [0087]    One implementation of each of the disclosed embolic filters can be adjunct to treatment of an ilio-femoral DVT. Here, prior to insertion of the thrombectomy device, the temporary embolic filter would be inserted into and deployed in the inferior vena cava and used as described above. In another implementation, the disclosed embolic filters can be used in the subclavian vein and axillary vein while treating patients with arterio-venous (a-v) access thrombosis. In other implementations, it is contemplated that the disclosed embolic filters can be used in any vascular bed. 
         [0088]    The present invention can thus be embodied in other specific forms without departing from its spirit or essential characteristics. The described aspects are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.