Patent Publication Number: US-2020281708-A1

Title: Systems and methods for protecting the cerebral vasculature

Description:
RELATED APPLICATIONS 
     This application claims the benefit of priority from U.S. Provisional Application No. 62/813,684 filed Mar. 4, 2019, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     In general, the present disclosure relates to medical devices for filtering blood. And, more particularly, in certain embodiments, to a method and a system of filters and deflectors for protecting the cerebral arteries from emboli, debris and the like dislodged during an endovascular or cardiac procedure. 
     BACKGROUND 
     There are four arteries that carry oxygenated blood to the brain, i.e., the right and left vertebral arteries, and the right and left common carotid arteries. Various procedures conducted on the human body, e.g., transcatheter aortic valve replacement (TAVR), aortic valve valvuloplasty, carotid artery stenting, closure of the left atrial appendage, mitral valve annuloplasty, repair or replacement, can cause and/or dislodge materials (whether native or foreign), these dislodged bodies can travel into one or more of the cerebral arteries resulting in, inter alia, stroke. Moreover, atheromas along and within the aorta and aortic arch can be dislodged as the TAVR catheter is advanced toward the diseased aortic valve and subsequently withdrawn after implantation is completed. In addition, pieces of the catheter itself can be stripped away during delivery and implantation. These various forms of vascular debris, whether native or foreign, can then travel into one or more cerebral arteries, embolize and cause, inter alia, a stroke or strokes. 
     There exist devices for protecting one or more cerebral arteries by either collecting (filters) or deflecting (deflectors) debris. Of the known medical devices, delivery systems, and methods, each has certain advantages and disadvantages. There is an ongoing need to provide alternative medical devices and methods as well as alternative methods for manufacturing and using medical devices. 
     SUMMARY 
     Vascular filters and deflectors and methods for filtering bodily fluids are disclosed herein. A blood filtering assembly can capture embolic material dislodged or generated during an endovascular procedure to inhibit or prevent the material from entering the cerebral vasculature. A blood deflecting assembly can deflect embolic material dislodged or generated during an endovascular procedure to inhibit or prevent the material from entering the cerebral vasculature. 
     In a first example, an embolic protection system for isolating cerebral vasculature may comprise a protection device having a proximal portion configured to remain outside the body and a distal portion. The distal portion may comprise an outer sheath and an expandable filter assembly comprising a variable diameter frame and a filter element. 
     Alternatively or additionally to any of the examples above, in another example, the variable diameter frame may comprise an inflatable tube. 
     Alternatively or additionally to any of the examples above, in another example, the inflatable tube may comprise an inflation cavity and a valve. 
     Alternatively or additionally to any of the examples above, in another example, the inflatable tube may be fluidly coupled to an inflation lumen configured to extend proximally from the expandable filter assembly to the proximal portion of the protection device. 
     Alternatively or additionally to any of the examples above, in another example, the variable diameter frame may comprise an open spaced coil including a plurality of windings. 
     Alternatively or additionally to any of the examples above, in another example, the variable diameter frame may comprise a laser cut tube having a plurality of openings. 
     Alternatively or additionally to any of the examples above, in another example, the variable diameter frame may comprise a shape memory material. 
     Alternatively or additionally to any of the examples above, in another example, the embolic protection system may further comprise a tension element extending through a central lumen of the variable diameter frame. 
     Alternatively or additionally to any of the examples above, in another example, a distal end of the tension element may be fixedly coupled to the variable diameter frame and a proximal end may extend proximally from the variable diameter frame. 
     Alternatively or additionally to any of the examples above, in another example, a proximal force exerted on the proximal end of the tension element may be configured to reduce a diameter of the variable diameter frame. 
     Alternatively or additionally to any of the examples above, in another example, the expandable filter assembly may comprise a distally facing opening. 
     Alternatively or additionally to any of the examples above, in another example, the expandable filter assembly may further comprise a support element. 
     Alternatively or additionally to any of the examples above, in another example, the support element may be one or more longitudinally extending tines. 
     Alternatively or additionally to any of the examples above, in another example, the support element may be an elongated hoop positioned between the variable diameter frame and a base of the filter element. 
     Alternatively or additionally to any of the examples above, in another example, the expandable filter assembly may further comprise a tether coupled to an end of the filter element. 
     In another example, a method of inhibiting embolic material from entering cerebral vasculature may comprise positioning a guidewire through a right subclavian artery and into an aortic arch and tracking a distal portion of a protection device over the guidewire. The distal portion of the protection device may comprise a proximal sheath, a proximal self-expanding filter assembly radially within the proximal sheath, a distal sheath, and a distal self-expanding filter assembly radially within the distal sheath. At least one of proximally retracting the proximal sheath and distally advancing the proximal self-expanding filter assembly may deploy the proximal self-expanding filter assembly from the proximal sheath in an innominate artery. The method may further comprise steering the distal sheath into the aortic arch and at least one of proximally retracting the distal sheath and distally advancing the distal self-expanding filter assembly to deploy the distal self-expanding filter assembly from the distal sheath in the aortic arch. After deploying the proximal self-expanding filter assembly and distal self-expanding filter assembly, the method may further comprise withdrawing the proximal sheath and the distal sheath. 
     Alternatively or additionally to any of the examples above, in another example, an opening of the distal self-expanding filter assembly may be positioned in the aortic arch upstream of an ostium of a left common carotid artery. 
     Alternatively or additionally to any of the examples above, in another example, the opening may be a distally facing opening. 
     Alternatively or additionally to any of the examples above, in another example, the distal self-expanding filter assembly may comprise a frame, a filter element, and a support element. 
     Alternatively or additionally to any of the examples above, in another example, the support element may be one or more longitudinally extending tines. 
     Alternatively or additionally to any of the examples above, in another example, the support element may be an elongated hoop positioned between the frame and a base of the filter element. 
     In another example, a method of inhibiting embolic material from entering cerebral vasculature may comprise positioning a guidewire through a right subclavian artery and into an ascending aorta and tracking a distal portion of a protection device over the guidewire. The distal portion of the protection device may comprise an outer sheath and a self-expanding filter assembly radially within the outer sheath. At least one of proximally retracting the outer sheath and distally advancing the self-expanding filter assembly may deploy the self-expanding filter assembly from the outer sheath in the ascending aorta. 
     Alternatively or additionally to any of the examples above, in another example, the self-expanding filter assembly may comprise a frame, a filter element, and a support element. 
     Alternatively or additionally to any of the examples above, in another example, the support element may be one or more longitudinally extending tines. 
     Alternatively or additionally to any of the examples above, in another example, the support element may be an elongated hoop positioned between the frame and a base of the filter element. 
     Alternatively or additionally to any of the examples above, in another example, the self-expanding filter assembly further may comprise a tether coupled to a base of a filter element. 
     Alternatively or additionally to any of the examples above, in another example, proximal actuation of the tether may draw the base of the filter element into the outer sheath. 
     Alternatively or additionally to any of the examples above, in another example, the self-expanding filter assembly may comprise an elongated tubular body. 
     Alternatively or additionally to any of the examples above, in another example, the elongated tubular body may comprise one or more woven, braided, or knitted filaments. 
     Alternatively or additionally to any of the examples above, in another example, a distal end of the elongated tubular body may comprise a hem. 
     In another example, a method of inhibiting embolic material from entering cerebral vasculature may comprise positioning a guidewire through a right subclavian artery and into an ascending aorta and tracking a distal portion of a protection device over the guidewire. The distal portion of the protection device may comprise an outer sheath and an inflatable filter assembly radially within the outer sheath. The method may further comprise at least one of proximally retracting the outer sheath and distally advancing the inflatable filter assembly to deploy the inflatable filter assembly from the outer sheath in the ascending aorta and delivering an inflation fluid to the inflatable filter assembly to expand a frame of the inflatable filter assembly. 
     Alternatively or additionally to any of the examples above, in another example, the frame of the inflatable filter assembly may comprise an inflation cavity and a valve. 
     Alternatively or additionally to any of the examples above, in another example, the inflation cavity may be fluidly coupled to an inflation lumen. 
     Alternatively or additionally to any of the examples above, in another example, the inflatable filter assembly may further comprise a filter element coupled to the frame. 
     Alternatively or additionally to any of the examples above, in another example, the method may further comprise removing the inflation fluid. 
     The above summary of exemplary embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which: 
         FIG. 1  illustrates a filter assembly to protect the cerebral vascular architecture; 
         FIG. 2  illustrates an alternate embodiment of a filter assembly to protect the cerebral vascular architecture; 
         FIG. 3  illustrates another alternate embodiment a filter assembly to protect the cerebral vascular architecture; 
         FIG. 4  illustrates another alternate embodiment a filter assembly to protect the cerebral vascular architecture; 
         FIG. 5  illustrates another alternate embodiment a filter assembly to protect the cerebral vascular architecture; 
         FIG. 6  illustrates another alternate embodiment a filter assembly to protect the cerebral vascular architecture; 
         FIG. 7  illustrates another alternate embodiment a filter assembly to protect the cerebral vascular architecture; and 
         FIG. 8  illustrates another alternate embodiment a filter assembly to protect the cerebral vascular architecture. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
     DETAILED DESCRIPTION 
     For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. 
     All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure. 
     The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
     Although some suitable dimensions ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed. 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary. 
     The currently marketed Sentinel system made by Claret Medical and embodiments of which are described in U.S. Pat. No. 9,492,264 mentioned above has two filters, a first which protects the right brachiocephalic artery, from which the right vertebral and right common carotid arteries typically originate, and a second filter in the left common carotid artery. In a typical patient, the left vertebral artery which provides approximately seven percent of the perfusion to the brain is left unprotected. 
     One disclosed solution to protecting the left vertebral is the use of a second device intended to be placed in the left arm, e.g. through the left radial artery, with a filter placed in the left subclavian from which the left vertebral typically originates. Embodiments of such a solution can be found in U.S. Pat. No. 9,566,144, the entirety of which is hereby incorporated by reference herein. 
     While cerebral embolic protection for transcatheter aortic valve replacement (TAVR) procedures may require that the embolic protection device allow for the passage of procedural catheters and devices over the aortic arch, procedures where the procedural catheters are introduced through the right heart or directly into the apex of the heart may allow for an embolic protection device to be positioned within the aorta or aortic arch. For example, procedures such as, but not limited to, left atrial appendage occlusion (LAAO), transcatheter mitral valve repair (TMVR), transcatheter mitral valve replacement, TAVR via apical access, ablation for afibrillation, ablation for ventricular tachycardia, etc. may allow for one or more embolic protection device(s) to be positioned upstream of the four cerebral arteries. The present application discloses several embodiments which may include a single filter and/or compound systems of filters and/or deflectors that can provide full cerebral protection. 
     The disclosure generally relates to devices and methods for filtering fluids and/or deflecting debris contained within fluids, including body fluids such as blood. A filtering or deflecting device can be positioned in an artery before and/or during an endovascular procedure (e.g., transcatheter aortic valve implantation (TAVI) or replacement (TAVR), transcatheter mitral valve implantation (TAMI) or replacement (TAMR), surgical aortic valve replacement (SAVR), other surgical valve repair, implantation, or replacement, cardiac ablation (e.g., ablation of the pulmonary vein to treat atrial fibrillation) using a variety of energy modalities (e.g., radio frequency (RF), energy, cryo, microwave, ultrasound), cardiac bypass surgery (e.g., open-heart, percutaneous), transthoracic graft placement around the aortic arch, valvuloplasty, etc.) to inhibit or prevent embolic material such as debris, emboli, thrombi, etc. resulting from entering the cerebral vasculature. 
     The devices may be used to trap and/or deflect particles in other blood vessels within a subject, and they can also be used outside of the vasculature. The devices described herein are generally adapted to be delivered percutaneously to a target location within a subject, but can be delivered in any suitable way and need not be limited to minimally-invasive procedures. 
       FIG. 1  is a schematic view of a portion of an aorta  10  including a protection system  40 . The aorta includes the ascending aorta  26 , descending aorta  28 , and aortic arch  30 . The aortic arch  30  is upstream of the left and right coronary arteries (not explicitly shown). The aorta  10  typically includes three great branch arteries: the brachiocephalic artery or innominate artery  12 , the left common carotid artery  14 , and the left subclavian artery  16 . The innominate artery  12  branches to the right carotid artery  18 , then the right vertebral artery  20 , and thereafter is the right subclavian artery  22 . The right subclavian artery  22  supplies blood to, and may be directly accessed from (termed right radial access), the right arm. The left subclavian artery  16  branches to the left vertebral artery  24 , usually in the shoulder area. The left subclavian artery  16  supplies blood to, and may be directly accessed from (termed left radial axis), the left arm. Four of the arteries illustrated in  FIG. 1  supply blood to the cerebral vasculature: (1) the left common carotid artery  14  (about 40% of cerebral blood supply); (2) the right common carotid artery  18  (about 40% of cerebral blood supply); (3) the right vertebral artery  20  (about 10% of cerebral blood supply); and (4) the left vertebral artery  24  (about 10% of cerebral blood supply). 
     It may be desirable to filter blood flow to all four arteries  14 ,  18 ,  20 ,  24  supplying blood to the brain and/or deflect particulates from entering the arteries  14 ,  18 ,  20 ,  24  supplying the brain. It may also be desirable to limit the number of incision sites or cuts required to deploy the system(s).  FIG. 1  illustrates deploying the protection system  40  using a right radial access incision. However, it is contemplated that the protection system  40  may deployed using a left radial access incision, a femoral incision, or other location, as desired. 
     The protection system  40  may include a proximal portion  42  and a distal portion  44 . The proximal portion  42  is configured to be held outside a patient&#39;s body and manipulated by a user such as a surgeon. The distal portion  44  is configured to be positioned such that a filter assembly  66  is located at a target location such as the ascending aorta  26  (or other location upstream of the four cerebral arteries  14 ,  18 ,  20 ,  24 ) to remove debris prior to reaching the brain and other distal organs. In some embodiments, the filter assembly  66  may be placed in the ascending aorta  26  between the aortic root (not explicitly shown) and the ostium of the innominate artery  12 . 
     The proximal portion  42  comprises a handle  54 , a control  56  such as a slider, an outer sheath  52 , a port  58 , optionally, an inner member translation control  60  such as a knob, and optionally, a hemostasis valve control  62  such as a knob. The proximal portion  42  may also comprise an inner member  64  radially inward of the outer sheath  52 . The proximal portion  42  may also comprise a filter wire  48  radially inward of the outer sheath  52 . The filter wire  48  is coupled to the filter assembly  66  at the distal portion  44 . The outer sheath  52  may have a diameter between about 4 French (Fr) (approximately 1.33 millimeters (mm)) and about 6 Fr (approximately 2 mm). The outer sheath  52  may have a diameter smaller than 4 Fr or greater than 6 Fr depending on the application. The outer sheath  52  may comprise an atraumatic distal tip. Other features of the protection system  40  and other protection systems described herein may be flexible and/or atraumatic. The outer sheath  52  may comprise a curvature, for example based on an intended placement location (e.g., the ascending aorta  26 ). 
     The slider  56  can be used to translate the outer sheath  52  and/or a filter assembly  66  (e.g., coupled to the filter wire  48 ). For example, the slider  56  may proximally retract the outer sheath  52 , the slider  56  may distally advance the filter assembly  66  out of the outer sheath  52 , or the slider  56  may proximally retract the outer sheath  52  and distally advance the filter assembly  66  (e.g., simultaneously or serially), which can allow the filter assembly  66  to radially expand. The slider  56  may also be configured to have an opposite translation effect, which can allow the filter assembly  66  to be radially collapsed (e.g., due to compression by the outer sheath  52 ) as the filter assembly  66  is drawn into the outer sheath  52 . Other deployment systems are also possible. For example, other deployment systems for opening and/or closing the filter assembly  66  may include, but are not limited to, gears or other features such as helical tracks (e.g., configured to compensate for any differential lengthening due to foreshortening of the filter assembly  66  and/or configured to convert rotational motion into longitudinal motion), a mechanical element, a pneumatic element, a hydraulic element, etc. 
     The port  58  may be in fluid communication with the inner member  64  (e.g., via a Y-shaped connector in the handle  54 ). The port  58  can be used to flush the device (e.g., with saline) before, during, and/or after use, for example, to remove air. The port  58  can also or alternatively be used to monitor blood pressure at the target location, for example by connecting an arterial pressure monitoring device in fluid communication with a lumen  68  of the outer sheath  52 . The port  58  can be also or alternatively be used to inject contrast agent, dye, thrombolytic agents such as tissue plasminogen activator (t-PA), etc. The slider  56  may not interact with the inner member  64  such that the inner member  64  is longitudinally movable independent of the filter assembly  66  and/or the outer sheath  52 . The inner member translation control  60  can be used to longitudinally translate the inner member  64 , for example before, after, and/or during deployment of the filter assembly  66 . The inner member translation control  60  may comprise a slider in the handle  54  (e.g., separate from the slider  56 ). 
     The rotatable hemostasis valve control  62  can be used to reduce or minimize fluid loss through the protection device  40  during use. For example, when positioned in ascending aorta  26 , the direction of blood flow with respect to the device  40  will be distal to proximal, so blood may be otherwise inclined to follow the pressure drop out of the device  40 . The hemostasis valve control  62  is illustrated as being rotatable, but other arrangements are also possible (e.g., longitudinally displaceable). The hemostasis valve control  62  may be configured to fix relative positions of the outer sheath  52  and the filter assembly  66 , for example as described with respect to the hemostasis valve in U.S. Pat. No. 8,876,796. The hemostasis valve  62  may comprise, for example, an elastomeric seal and hemostasis valve nut. 
     The distal portion  44  may comprise the outer sheath  52 , a filter assembly  66  radially inward of the outer sheath  52  (in a delivery configuration), and optionally the inner member  64 . The filter assembly  66  may be radially between the outer sheath  52  and the inner member  64  (e.g., radially inward of the outer sheath  52  and the inner member  64  radially inward of the filter assembly  66 ) in a delivery state or position. 
     The filter assembly  66  may include a support element or frame  46  and a filter element  50 . The frame  46  may be a hoop-like structure configured to generally provide expansion support to the filter element  50  when the filter assembly  66  is in the expanded state (as shown in  FIG. 1 ). In the expanded state, the filter element  50  may be configured to filter fluid (e.g., blood) flowing through the filter element  50  and to inhibit or prevent particles (e.g., embolic material) from flowing through the filter element  50  by capturing the particles in the filter element  50 . 
     The frame  46  may be configured to engage or appose the inner walls of a lumen (e.g., blood vessel) in which the filter assembly  66  is expanded such that the filter assembly  66  is sealed against the wall of the vessel to ensure that most, if not all, blood flow exiting the aortic valve flows through the filter membrane  50 . The frame  46  may comprise or be constructed of, for example, nickel titanium (e.g., nitinol), nickel titanium niobium, chromium cobalt (e.g., MP35N, 35NLT), copper aluminum nickel, iron manganese silicon, silver cadmium, gold cadmium, copper tin, copper zinc, copper zinc silicon, copper zinc aluminum, copper zinc tin, iron platinum, manganese copper, platinum alloys, cobalt nickel aluminum, cobalt nickel gallium, nickel iron gallium, titanium palladium, nickel manganese gallium, stainless steel, combinations thereof, and the like. The frame  46  may comprise a wire (e.g., having a round (e.g., circular, elliptical) or polygonal (e.g., square, rectangular) cross-section). For example, in some embodiments, the frame  46  comprises a straight piece of nitinol wire shape set into a circular or oblong hoop or hoop with one or two straight legs running longitudinally along or at an angle to a longitudinal axis of the filter assembly  66 . At least one of the straight legs may be coupled to or form a part of the filter wire  48 . The straight legs may be on a long side of the filter assembly  66  and/or on a short side of the filter assembly  66 . In other embodiments, the frame  46  may be formed from laser cut nitinol (or other suitable material). The frame  46  may form a shape of an opening  70  of the filter assembly  66 . The opening  70  may be circular, elliptical, or any shape that can appropriately appose sidewalls of a vessel such as the ascending aorta  26 , aortic arch  30 , innominate artery  12 , etc. The filter assembly  66  may have a generally distally-facing opening  70 . In other embodiments, the opening  70  may be proximally facing. The orientation (e.g., proximal facing or distal facing) of the opening  70  relative to the system  40  may vary depending on where the access incision is located. 
     The frame  46  may take other shapes as desired. In some embodiments, the frame  46  may take the general shape of an expandable or self-expanding stent frame. For example, the frame  46  may include a proximal hoop and a distal hoop. The proximal and distal hoops may be interconnected with one or more generally longitudinally extending struts. Some illustrative frames are described in commonly assigned U.S. Pat. No. 9,566,144, the entirety of which is hereby incorporated by reference. 
     The frame  46  may include a radiopaque marker such as a small coil wrapped around or coupled to the hoop to aid in visualization under fluoroscopy. In some embodiments, the frame  46  may be formed from or coated with a radiopaque material, such as tantalum, platinum iridium or other suitable material, in order to make the hoop visible under fluoroscopy. In some embodiments, the frame may comprise a shape other than a hoop, for example, a spiral. In some embodiments, the filter assembly  66  may not include or be substantially free of a frame. 
     In some embodiments, the frame  46  and the filter element  50  form an oblique truncated cone having a non-uniform or unequal length around and along the length of the filter assembly  66 . In such a configuration, along the lines of a windsock, the filter assembly  66  has a larger opening  70  (upstream) diameter and a reduced ending (downstream) diameter. 
     The filter element  50  may include pores configured to allow blood to flow through the filter element  50 , but that are small enough to inhibit and/or prevent particles such as embolic material from passing through the filter element  50 . The filter element  50  may comprise a filter membrane such as a polymer (e.g., polyurethane, polytetrafluoroethylene (PTFE)) film mounted to the frame  46 . In some embodiments, the filter element  50  may be made of a nitinol mesh, a stainless steel mesh, a polymer mesh (e.g., polyether ether ketone (PEEK), or any other suitable material or construction. For example, the filter element  50  may be formed from a knitted or woven material. The filter element  50  may have a thickness between about 0.0001 inches (0.0025 mm) and about 0.03 inches (0.76 mm) (e.g., no more than about 0.0001 inches, about 0.001 inches, about 0.005 inches, about 0.01 inches, about 0.015 inches, about 0.02 inches, about 0.025 inches, about 0.03 inches, ranges between such values, etc.). 
     The filter element  50  may comprise a plurality of pores or holes or apertures extending through the film. The film may be formed by weaving or braiding filaments or membranes and the pores may be spaces between the filaments or membranes. The filaments or membranes may comprise the same material or may include other materials (e.g., polymers, non-polymer materials such as metal, alloys such as nitinol, stainless steel, etc.). The pores of the filter element  50  are configured to allow fluid (e.g., blood) to pass through the filter element  50  and to resist the passage of embolic material that is carried by the fluid. The pores can be circular, elliptical, square, triangular, or other geometric shapes. Certain shapes such as an equilateral triangular, squares, and slots may provide geometric advantage, for example restricting a part larger than an inscribed circle but providing an area for fluid flow nearly twice as large, making the shape more efficient in filtration verses fluid volume. The pores may be laser drilled into or through the filter element  50 , although other methods are also possible (e.g., piercing with microneedles, loose braiding or weaving). The pores may have a lateral dimension (e.g., diameter) between about 10 micron (μm) and about 1 mm (e.g., no more than about 10 μm, about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 400 μm, about 500 μm, about 750 μm, about 1 mm, ranges between such values, etc.). Other pore sizes are also possible, for example, depending on the desired minimum size of material to be captured. 
     The material of the filter element  50  may comprise a smooth and/or textured surface that is folded or contracted into the delivery state by tension or compression into a lumen. For example, the filter element  50  and the frame  46  may be collapsed within the lumen  68  of the outer tubular member  52  for delivery. A reinforcement fabric may be added to or embedded in the filter element  50  to accommodate stresses placed on the filter element  50  during compression. A reinforcement fabric may reduce the stretching that may occur during deployment and/or retraction of the filter assembly  66 . The embedded fabric may promote a folding of the filter element  50  to facilitate capture of embolic debris and enable recapture of an elastomeric membrane. The reinforcement material could comprise, for example, a polymer and/or metal weave to add localized strength. The reinforcement material could be imbedded into the filter element  50  to reduce thickness. For example, imbedded reinforcement material could comprise a polyester weave mounted to a portion of the filter element  50  near the longitudinal elements of the frame  46  where tensile forces act upon the frame  46  and filter element  50  during deployment and retraction of the filter assembly  66  from/into the outer sheath  52 . 
     In some cases, the filter assembly  66  may include a self-expanding filter assembly (e.g., comprising a superelastic material with stress-induced martensite due to confinement in the outer sheath  52 ). The filter assembly  66 , or portions thereof, may comprise a shape-memory material configured to self-expand upon a temperature change (e.g., heating to body temperature). The filter assembly  66 , or portions thereof, may comprise a shape-memory or superelastic frame (e.g., comprising a distal end hoop comprising nitinol) and a microporous material (e.g., comprising a polymer including laser-drilled holes) coupled to the frame, for example similar to the filter assemblies described in U.S. Pat. No. 8,876,796. 
     The filter assembly  66  may be coupled (e.g., crimped, welded, soldered, etc.) to a distal end of the deployment wire or filter wire  48  via a strut or wire, although this is not required. When both or all of the filter wire  48  and the strut are provided, the filter wire  48  and the strut may be coupled within outer sheath  52  proximal to the filter assembly  66  using a crimp mechanism. In other embodiments, the filter wire  48  and the strut may be a single unitary structure. The filter wire  48  and/or strut can comprise a rectangular ribbon, a round (e.g., circular, elliptical) filament, a portion of a hypotube, a braided structure (e.g., as described herein), combinations thereof, and the like. The filter wire  48  can be coupled to the handle  54  and/or a slider to provide differential longitudinal movement versus the outer sheath  52 , as shown by the arrows  72 , which can sheathe and unsheathe the filter assembly  66  from the outer sheath  52 . As described herein, the filter assembly may be unsheathed through actuation of the outer sheath  52 . 
     The filter assembly  66  in an expanded, unconstrained state may have a maximum diameter or effective diameter (e.g., if the mouth is in the shape of an ellipse) sized for the desired vessel and/or a patient in which it is to be deployed. For example, a filter assembly  66  deployed in the aorta  10  may have a larger diameter than a filter assembly  66  deployed in the innominate artery  12 . Different diameters can allow treatment of a selection of subjects having different vessel sizes. The filter assembly  66  may have a maximum length selected to minimize a pressure drop caused by the filter assembly  66 . For example, passing the blood through a filter may reduce the flow rate of the blood passing through the filter and thus introduce a pressure drop from the opening  70  of the filter assembly  66  to the tail of the filter assembly  66 . The length of the filter element  50  may be selected to reduce or minimize the pressure drop across the filter assembly  66 . It is further contemplated that different filter lengths can allow treatment of a selection of subjects having different vessel sizes. 
     It is contemplated that a filter assembly  66  configured to be positioned within the ascending aorta  26  may be larger than a filter assembly  66  configured to be positioned in the innominate artery  12 . For example, the ascending aorta  26  may have a diameter in the range of about 30 to 40 mm while the innominate artery  12  may have a diameter in the range of about 9 to 15 mm. Thus, a filter assembly  66  configured to be positioned within the ascending aorta may require a larger diameter such that the filter assembly  66  is in apposition with the vessel wall. However, a larger filter assembly  66  may increase the risk that the filter frame or hoop  46  may fold back on itself due to the high flow of blood through the filter which creates a high load on the filter due to the pressure drop created when blood flows through the filter membrane  50 . For example, the frame  46  may bend back toward the outer shaft  52 . In some cases, stiffening the frame  46  at the point where the frame  46  transitions into and/or connects to the filter wire  48  may help prevent the filter assembly  66  from folding back on itself. Alternatively or additionally, the surface area of the filter element  50  may be increased by, for example, increasing a length of the filter element  50 . This may increase the number of holes or pores in the filter element  50  thus allowing more blood to flow through which may in turn reduce the pressure on the filter element  50 . Other methods of increasing the surface area (and hence the number or area of pores) of the filter element  50  may also be used to reduce the pressure drop. For example, pleats or folds of material may be added to the filter element  50  to increase the surface area. 
     In some methods of use, the filter assembly  66  may first be withdrawn into the outer sheath  52  to collapse the filter assembly  66 . A guidewire  74  may be inserted into a lumen (not explicitly shown) of the inner member  64  through a proximal or distal end thereof. Positioning the guidewire  74  within a lumen of the inner member  64  may allow for free movement of the guidewire  74  and may prevent compression of the guidewire  74  when the filter assembly  66  is sheathed in the outer sheath  52 . The filter system  40  is advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. Alternatively, the filter system  40  may be advanced using left radial access. In a variety of medical procedures, a medical instrument is advanced through a subject&#39;s femoral artery, which is larger than the right radial artery. A delivery catheter used in femoral artery access procedures has a larger outer diameter than would be allowed in a filter system advanced through a radial artery. Additionally, in some uses the filter system  40  is advanced from the right radial artery into the aorta via the brachiocephalic trunk. The radial artery has the smallest diameter of the vessels through which the system is advanced. The radial artery therefore limits the size of the system that can be advanced into the subject when the radial artery is the access point. The outer diameters of the systems described herein, when advanced into the subject via a radial artery, are therefore smaller than the outer diameters of the guiding catheters (or sheaths) typically used when access is gained via a femoral artery. 
     When the guidewire is used, the system  40  may be advanced along with the guidewire  74 , the guidewire  74  extending distally beyond a distal end of the system  40  to protect the vessel from damage from the tip of the outer sheath  52 . The system  40  may be advanced until the distal end of the outer sheath  52  is positioned above or adjacent to the aortic valve (not explicitly shown). Alternatively, the guidewire  74  may be advanced to the desired location and the system  40  advanced over the guidewire  74  after the distal end of the guidewire  74  is positioned at the target location. 
     In certain anatomies, when the outer sheath  52  is advanced through the innominate artery  12  and into the aorta  10 , the outer sheath  52  may tend to advance down the descending aorta  28  instead of the ascending aorta  26 . In order to prevent this, or adjust for this, the outer sheath  52  may be made steerable so that the operator can guide the tip of the outer sheath  52  into the ascending aorta  26  and towards the aortic valve. In one embodiment, the outer sheath  52  may include a deflectable tip that is actuated by a pull-wire controlled at the device handle  54 . Alternatively, or additionally, the outer sheath  52  may include a pre-shaped deflected tip (e.g., similar to the J-tip on a guidewire) that would allow the operator to rotate the outer sheath  52  to aim the outer sheath  52  tip down the ascending aorta  26 . It is further contemplated that a pre-shaped tip may be straightened by inserting a semi-rigid or rigid stylet into a lumen in the outer sheath  52  (and/or inner member  64 ). This would allow the outer sheath  52  to be inserted while straight, and then when the tip of the outer sheath  52  is in the aorta  10 , the stylet could be withdrawn, thus allowing the pre-shaped tip of the outer sheath  52  to deflect in the direction of the ascending aorta  26 . Other methods of deflecting the tip may also be used 
     When placing the system  40 , it may be desirable to avoid contact with the aortic valve to avoid damaging it. This may be accomplished by inserting a pigtail angiography catheter into the aortic arch through either a femoral access or through a left radial artery access, and injecting contrast so that the aortic valve may be located and imaged using fluoroscopy. However, it may be desired to not require the addition of femoral access for an angiography catheter given that femoral access is not required for all index procedure catheters, and femoral access is associated with increased access site vascular complications. It is contemplated that an angiography catheter (in some cases, a 4 Fr angiography catheter) may be advanced through an inner lumen  68  of the outer sheath  52  and/or the inner member  64  and into the filter assembly  66  after deployment of the filter assembly  66 . Contrast may then be injected through the angiography catheter. In another embodiment, contrast may be injected directly through the guidewire lumen of the inner member  64  or through the inner lumen of the outer sheath  52 . In yet another embodiment, contrast may not be used and the filter assembly  66  may be placed with imaging using transesophageal echocardiography (TEE). 
     Once the system  40  is in a desired position, the guidewire  74  may then be proximally retracted. The system  40  may be delivered to the ascending aorta  26  in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where the filter assembly  66  is in a collapsed configuration within the system  40  (e.g., within the outer sheath  52 ). The outer sheath  52  is retracted proximally to allow the filter frame  46  to expand to an expanded configuration against the wall of the ascending aorta  26  upstream of the ostium of the innominate artery  12 , as is shown in  FIG. 1 . The filter element  50  is secured either directly or indirectly to the support frame  46  and is therefore reconfigured to the configuration shown in  FIG. 1  upon deployment of the frame  46 . Alternatively, or additionally, the filter assembly  66  may be distally advanced from the outer sheath  52  through distal actuation of the filter wire  48 . Once expanded, the filter assembly  66  filters blood traveling through the ascending aorta  26 , and therefore filters blood traveling into innominate artery  12 , the right common carotid artery  18 , the right vertebral artery  20 , the left common carotid artery  14 , the left subclavian artery  16 , the left vertebral artery  24 , and the descending aorta  28 . The expanded filter assembly  66  is therefore in position to prevent foreign particles from traveling into all four cerebral arteries  14 ,  18 ,  20 ,  24 , and into the cerebral vasculature. It is contemplated that the inner member  64  may be removable following deployment of the filter assembly  66 , although this is not required. 
     The filter assembly  66  may be re-sheathed or positioned within the outer sheath  52  to facilitate repositioning of the filter assembly to optimize the placement of the filter assembly  66 . To re-sheathe the filter assembly  66 , it is contemplated that the outer sheath  52  may be distally advanced over the filter assembly  66 , the filter assembly  66  proximally retracted into the outer sheath  52  via the filter wire  48 , or combinations thereof. The system  40  may then be repositioned and the filter assembly  66  redeployed. The filter assembly  66  may be re-sheathed, repositioned, and redeployed as many times as desired to optimize the placement of the filter assembly  66 . 
     Once the filter assembly  66  has been deployed, the index procedure (e.g., LAOO, TMVR, ablation, etc.) may then be performed. Following the completion of the index procedure, the filter assembly  66  may be re-sheathed (e.g., collapsed within the outer sheath  52 ) and the system  40  removed, with any captured debris removed along with the filter assembly  66 . 
       FIG. 2  illustrates an alternative protection device  100  including a distal filter assembly  102  and a proximal filter assembly  104  and positioned using a right radial access incision. The protection device  100  may include a distal end region  106  and a proximal end region (not explicitly shown). The proximal end region may be configured to be held and manipulated by a user such as a surgeon. The distal end region  106  may be configured to be positioned at a target location such as, but not limited to, the innominate artery  12  and/or the aortic arch  30 . When the distal end region  106  is so deployed, blood is filtered prior to entering the left common carotid artery  14 , the left subclavian artery  16 , the left vertebral artery  24 , the right common carotid artery  18 , and the right vertebral artery  20 . 
     The proximal end region may be similar in form and function to the proximal end region  42  described herein. While not explicitly shown, the proximal end region may include a handle, a control such as a slider, an outer sheath, a port, an inner member translation control such as a knob, and hemostasis valve control such as a knob. In some embodiments, the proximal end region may include fewer or more control elements than those illustrated and described with respect to  FIG. 1 . The proximal end region may also include an inner member radially inward of the outer sheath  108 . While not explicitly shown, the proximal end region may also include a filter wire radially inward of the outer sheath (and sometimes radially outward of the inner member). Some illustrative filter wires are described in commonly assigned U.S. Pat. No. 9,566,144, the entirety of which is hereby incorporated by reference. 
     The distal end region  106  may include a first or distal filter assembly  102  configured to be deployed within the aortic arch  30  (upstream of the ostium of the left common carotid artery  14 ) and a second or proximal filter assembly  104  configured to deployed within the innominate artery  12 . The distal end region  106  may further include a proximal (or outer) sheath  108 , a proximal shaft  110  coupled to an expandable proximal filter assembly  104 , a distal shaft  112  coupled to a distal articulatable sheath  114 , a distal filter assembly  102 , and guiding member  116 . 
     The proximal shaft  110  is co-axial with proximal sheath  108 , and a proximal region  118  of proximal filter assembly  104  is secured to proximal shaft  110 . In its collapsed configuration (not explicitly shown), the proximal filter assembly  104  may be disposed within proximal sheath  108  and is disposed distally relative to the proximal shaft  110 . The proximal sheath  108  may be axially (e.g., distally and proximally) movable relative to proximal shaft  110  and the proximal filter assembly  104 . The system  100  may also include a distal sheath  114  secured to a distal region of the distal shaft  112 . The distal shaft  112  may be co-axial with the proximal shaft  110  and the proximal sheath  108 . The distal sheath  114  and distal shaft  112  may be secured to one another and axially movable relative to the proximal sheath  108 , the proximal shaft  110 , and the proximal filter assembly  104 . The system  100  may also include a distal filter assembly  102  carried by the guiding member  116 . While not explicitly shown, the distal filter assembly  102  may be maintained in a collapsed configuration within the distal sheath  114 . The guiding member  116  may be coaxial with the distal sheath  114  and the distal shaft  112  as well as the proximal sheath  108  and the proximal shaft  110 . The guiding member  116  may be axially movable relative to the distal sheath  114  and the distal shaft  112  as well as the proximal sheath  108  and the proximal shaft  110 . The proximal sheath  108 , the distal sheath  114 , and the guiding member  116  may each be adapted to be independently moved axially relative to one other. That is, the proximal sheath  108 , the distal sheath  114 , and the guiding member  116  are adapted for independent axial translation relative to each of the other two components. It is contemplated that a handle, which may be similar in form and function to the handle  54  described herein, may include control elements (such as, but not limited to, slides, switches, buttons, dials, etc.) configured to individually actuate the proximal sheath  108 , the distal sheath  114 , and the guiding member  116 . 
     The proximal filter assembly  104  may include a support element or frame  120  and a filter element  122 . Similarly, the distal filter assembly  102  includes support element  124  and a filter element  126 . The frames  120 ,  124  may generally provide expansion support to the filter elements  122 ,  126  in the expanded state. In the expanded state, the filter elements  122 ,  126  are configured to filter fluid (e.g., blood) flowing through the filter elements  122 ,  126  and to inhibit or prevent particles (e.g., embolic material) from flowing through the filter elements  122 ,  126  by capturing the particles in the filter elements  122 ,  126 . The frames  120 ,  124  are configured to engage or appose the inner walls of a lumen (e.g., blood vessel) in which the filter assembly  102 ,  104  is expanded. The frames  120 ,  124  may be similar in form and function the frame  46  described herein and the filter elements  122 ,  126  may be similar in form and function to the filter element  50  described herein. For example, in some embodiments, the frames  120 ,  124  may comprise a straight piece of nitinol wire shape set into a circular or oblong hoop or hoops with one or two straight legs running longitudinally along or at an angle to a longitudinal axis of the filter assembly  102 ,  104 . At least one of the straight legs may be coupled to a filter wire  130  or a strut  128 , as shown with respect to the distal filter assembly  102 . The straight legs may be on a long side of the filter assembly  102 ,  104  and/or on a short side of the filter assembly  102 ,  104 . The frames  120 ,  124  may form a shape of an opening  132 ,  134  of the filter assembly  102 ,  104 . The opening  132 ,  134  may be circular, elliptical, or any shape that can appropriately appose sidewalls of a vessel. The distal filter assembly  102  may have a generally proximally-facing opening  134 . The proximal filter assembly  104  may have a generally distally-facing opening  132 . The orientation of the opening  132 ,  134  may vary depending on where the access incision is located. For example, as shown in  FIG. 2 , the proximal filter assembly  104  has a generally distally-facing opening  132 , and the distal filter assembly  102  has a generally proximally-facing opening  134  relative to the system  100  for introduction via the right side of the body. It is contemplated that the configuration of the openings  132 ,  134  may be reversed for introduction via the left side of the body. The filter assemblies  102 ,  104  can be thought of as facing opposite directions. 
     In some cases, the filter assembly  102 ,  104  may include a self-expanding filter assembly (e.g., comprising a superelastic material with stress-induced martensite due to confinement in the outer sheath  108  and/or the distal sheath  114 ). The filter assembly  102 ,  104  may comprise a shape-memory material configured to self-expand upon a temperature change (e.g., heating to body temperature). The filter assembly  102 ,  104  may comprise a shape-memory or superelastic frame (e.g., comprising a distal end hoop comprising nitinol) and a microporous material (e.g., comprising a polymer including laser-drilled holes) coupled to the frame, for example similar to the filter assemblies described in U.S. Pat. No. 8,876,796. 
     The distal filter assembly  102  may be coupled (e.g., crimped, welded, soldered, etc.) to a distal end of a deployment wire or filter wire  130  via a strut or wire  128 , although this is not required. In some embodiments, the proximal filter assembly  104  may also be coupled to a filter wire or strut (not explicitly shown). When both or all of the filter wire  130  and the strut  128  are provided, the filter wire  130  and the strut  128  may be coupled within the guiding member  116  proximal to the filter assembly  102  using a crimp mechanism. In other embodiments, the filter wire  130  and the strut  128  may be a single unitary structure. The filter wire  130  and/or strut  128  can comprise a rectangular ribbon, a round (e.g., circular, elliptical) filament, a portion of a hypotube, a braided structure (e.g., as described herein), combinations thereof, and the like. The filter wire  130  can be coupled to the handle (not explicitly shown) and/or a slider to provide differential longitudinal movement versus the outer sheath  108 , which can sheathe and unsheathe the distal filter assembly  102  from the distal sheath  114 . Similarly, the proximal filter assembly  104  may be unsheathe through actuation of a mechanism on the handle or through movement of the handle itself. 
     The filter assemblies  102 ,  104  in an expanded, unconstrained state may have a maximum diameter or effective diameter (e.g., if the mouth is in the shape of an ellipse). The diameter can be between about 1 mm and about 40 mm, or more. Other diameters or other types of lateral dimensions are also possible. Different diameters can allow treatment of a selection of subjects having different vessel sizes. The filter assemblies  102 ,  104  may have a maximum length. The length can be between about 7 mm and about 50 mm, or more. Other lengths are also possible, for example based on the diameter or effective diameter. For example, the length of the filter assembly  102 ,  104  may increase as the diameter increases, and the length of the filter assembly  102 ,  104  may decrease as the diameter decreases. A distance from an apex of the mouth of the filter assembly  102 ,  104  to an elbow in the frame may be about 35 mm. Different lengths can allow treatment of a selection of subjects having different vessel sizes. 
     As described in more detail herein, the distal sheath  114  may be adapted to be steered, or bent, relative to the proximal sheath  108  and the proximal filter assembly  104 . As the distal sheath  114  is steered, the relative directions in which the openings face will be adjusted. Regardless of the degree to which the distal sheath  114  is steered, the filter assemblies  102 ,  104  are still considered to having openings facing opposite directions. For example, the distal sheath  114  could be steered to have an approximately 90 degree bend, in which case the filter assemblies  102 ,  104  would have openings  132 ,  134  facing at generally orthogonal angles, as shown in  FIG. 2 . The directions of the filter openings  132 ,  134  are therefore described if the system were to assume a substantially straightened configuration (not explicitly shown). The proximal filter element  122  may taper down in the proximal direction from support element  120 , while the distal filter element  126  may taper down in the distal direction from support element  124 . A fluid, such as blood, flows through the opening and passes through the pores in the filter elements  122 ,  126 , while the filter elements  122 ,  126  are adapted to trap foreign particles therein and prevent their passage to a location downstream of the filter assemblies. 
     The filter assemblies  102 ,  104  may be secured to separate system components. For example, the proximal filter assembly  104  is secured to the proximal shaft  110 , while the distal filter assembly  102  is secured to guiding member  116 . In  FIG. 2 , the filter assemblies  102 ,  104  are secured to independently actuatable components. This may allow the filter assemblies  102 ,  104  to be independently positioned and controlled. Additionally, the filter assemblies  102 ,  104  may be collapsed within two different tubular members in their collapsed configurations. For example, the proximal filter assembly  104  is collapsed within proximal sheath  108 , while the distal filter assembly  102  is collapsed within distal sheath  114 . In the system&#39;s delivery configuration, the filter assemblies  102 ,  104  are axially-spaced from one another. For example, in  FIG. 2 , the distal filter assembly  102  is distally-spaced relative to proximal filter assembly  104 . However, in an alternative embodiment, the filter assemblies  102 ,  104  may be positioned such that a first filter is located within a second filter. 
     In some embodiments, the distal sheath  114  and the proximal sheath  108  have substantially the same outer diameter. When the filter assemblies  102 ,  104  are collapsed within the respective sheaths  114 ,  108 , the sheath portion of the system  100  therefore has a substantially constant outer diameter, which can ease the delivery of the system  100  through the patient&#39;s body and increase the safety of the delivery. The distal and proximal sheaths  114 ,  108  may have substantially the same outer diameter, both of which have larger outer diameters than the proximal shaft  110 . The proximal shaft  110  may have a larger outer diameter than the distal shaft  112 , wherein the distal shaft  112  is disposed within the proximal shaft  110 . The guiding member  116  may have a smaller diameter than the distal shaft  112 . In some embodiments, the proximal and distal sheaths  108 ,  114  have an outer diameter between about 3 French (F) and 14 F. In certain embodiments, the outer diameter is between about 4 F and 8 F. In still other embodiments, the outer diameter is between 4 F and 6 F. In some embodiments, the sheaths  108 ,  114  have different outer diameters. For example, the proximal sheath  108  can have a size of 6 F, while the distal sheath  114  has a size of 5 F. In an alternate embodiment the proximal sheath  108  is about 5 F and the distal sheath  114  is about 4 F. These are just examples and are not intended to limit the sheaths  108 ,  114  to a particular size. A distal sheath  114  with a smaller outer diameter than the proximal sheath  108  may reduce the delivery profile of the system  100  and can ease delivery. 
     In some methods of use, the filter system  100  is advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. In a variety of medical procedures, a medical instrument is advanced through a subject&#39;s femoral artery, which is larger than the right radial artery. A delivery catheter used in femoral artery access procedures may have a larger outer diameter than would be allowed in a filter system advanced through a radial artery. Additionally, in some uses the filter system is advanced from the right radial artery into the aorta via the brachiocephalic trunk. The radial artery has the smallest diameter of the vessels through which the system is advanced. The radial artery therefore limits the size of the system that can be advanced into the subject when the radial artery is the access point. The outer diameters of the systems described herein, when advanced into the subject via a radial artery, are therefore smaller than the outer diameters of the guiding catheters (or sheaths) typically used when access is gained via a femoral artery. In some embodiments, the system  100  may be advanced over a guidewire  136 , although this is not required. 
     The system  100  may be delivered to the aortic arch  30  and the innominate artery  12  in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where both filter assemblies  102 ,  104  are in collapsed configurations within the system (e.g., within the distal and proximal sheaths  114 ,  108 ). The distal articulating sheath  114  may be independently movable with 3 degrees of freedom relative to the proximal sheath  108  and proximal filter assembly  104 . In some embodiments, the proximal sheath  108  and the distal sheath  114  may be releasably coupled together. For example, the proximal sheath  108  can be coupled to the distal sheath  114  using an interference fit, a friction fit, a spline fitting, end to end butt fit, or any other type of suitable coupling between the two sheaths  108 ,  114 . When coupled together, the components move as a unit. For example, the proximal sheath  108 , the proximal shaft  110 , the proximal filter assembly  104 , the distal shaft  112 , and the distal filter assembly  102  will rotate and translate axially (in the proximal or distal direction) as a unit. When the proximal sheath  108  is retracted to allow the proximal filter assembly  104  to expand, the distal sheath  114  can be independently rotated, steered, or translated axially (either in the proximal direction or distal direction). The distal sheath  114  therefore has 3 independent degrees of freedom: axial translation, rotation, and steering. The adaptation to have 3 independent degrees of freedom is advantageous when positioning the distal sheath  114  in a target location, details of which are described herein. 
     The system  100  is advanced into the subject&#39;s right radial artery through an incision in the right arm, or alternately through the right brachial artery. The system is advanced through the right subclavian artery  22  and into the brachiocephalic or innominate artery  12 , and a portion of the system is positioned within the aortic arch  30 . The proximal sheath  108  is retracted proximally to allow proximal filter support element  120  to expand to an expanded configuration against the wall of the innominate artery  12 , as is shown in  FIG. 2 . The proximal filter element  122  is secured either directly or indirectly to support element  120  and is therefore reconfigured to the configuration shown in  FIG. 2 . The position of distal sheath  114  can be substantially maintained while proximal sheath  108  is retracted proximally. Once expanded, the proximal filter assembly  104  filters blood traveling through the innominate artery  12 , and therefore filters blood traveling into the right common carotid artery  18  and the right vertebral artery  20 . The expanded proximal filter assembly  104  is therefore in position to prevent foreign particles from traveling into the right common carotid artery  18  and the right vertebral artery  20  and into the cerebral vasculature. 
     The distal sheath  114  is then steered, or bent, and a distal end of the distal sheath  114  is positioned within the aortic arch  30  such that the distal filter support element  124  is configured to be deployed upstream of the ostium of the left common carotid artery  14  (and downstream of the ostium of the innominate artery  12 ). The guiding member  116  is thereafter advanced distally relative to distal sheath  114 , allowing the distal support element  124  to expand from a collapsed configuration to a deployed configuration against the wall of the aortic arch  30 , as shown in  FIG. 2 . The distal filter element  126  is also reconfigured into the configuration shown in  FIG. 2 . Once expanded, the distal filter assembly  102  filters blood traveling through the aortic arch  30  and hence the left common carotid artery  14  and left subclavian artery  16 . The distal filter assembly  102  is therefore in position to trap foreign particles and prevent them from traveling into the cerebral vasculature. In some embodiments, the distal filter assembly  102  may be deployed prior to the deployment of the proximal filter assembly  104 . 
       FIG. 3  is a partial perspective view of another illustrative filter assembly  200 . The filter assembly  200  may be configured to be advanced to the target location within an outer sheath  202  that may be similar in form and function to the outer sheath  52  described with respect to  FIG. 1 . The filter assembly  200  may include a support element or frame  204  and a filter element  206 . The frame  204  may be a hoop-like structure configured to generally provide expansion support to the filter element  206  in the expanded state. In the expanded state, the filter element  206  may be configured to filter fluid (e.g., blood) flowing through the filter element  206  and to inhibit or prevent particles (e.g., embolic material) from flowing through the filter element  206  by capturing the particles in the filter element  206 . 
     The frame  204  may be similar in form and function the frame  46  described herein and the filter element  206  may be similar in form and function to the filter element  50  described herein. For example, in some embodiments, the frame  204  comprises a straight piece of nitinol wire shape set into a circular or oblong hoop or hoop with one or two straight legs  208  running longitudinally along or at an angle to a longitudinal axis of the filter assembly  200 . At least one of the straight legs may be coupled to a filter wire  210  or a strut. The straight legs may be on a long side of the filter assembly  200  and/or on a short side of the filter assembly  200 . The frame  204  may form a shape of an opening  212  of the filter assembly  200 . The opening  212  may be circular, elliptical, or any shape that can appropriately appose sidewalls of a vessel. The filter assembly  200  may have a generally distally-facing opening  212 . In other embodiments, the opening  212  may be proximally facing. The orientation of the opening  212  may vary depending on where the access incision is located and/or the vessel in which the filter assembly  200  is to be positioned. 
     In some cases, the filter assembly  200  may include a self-expanding filter assembly (e.g., comprising a superelastic material with stress-induced martensite due to confinement in the outer sheath  202 ). The filter assembly  200  may comprise a shape-memory material configured to self-expand upon a temperature change (e.g., heating to body temperature). The filter assembly  200  may comprise a shape-memory or superelastic frame (e.g., comprising a distal end hoop comprising nitinol) and a microporous material (e.g., comprising a polymer including laser-drilled holes) coupled to the frame, for example similar to the filter assemblies described in U.S. Pat. No. 8,876,796. 
     The filter assembly  200  may be coupled (e.g., crimped, welded, soldered, etc.) to a distal end of a deployment wire or filter wire  210  via a strut or wire, such as, but not limited to the leg  208 , although this is not required. When both or all of the filter wire  210  and the strut  208  are provided, the filter wire  210  and the strut may be coupled proximal to the filter assembly  200  using a crimp mechanism. In other embodiments, the filter wire  210  and the strut  208  may be a single unitary structure. The filter wire  210  and/or strut  208  can comprise a rectangular ribbon, a round (e.g., circular, elliptical) filament, a portion of a hypotube, a braided structure (e.g., as described herein), combinations thereof, and the like. The filter wire  210  can be coupled to the handle (not explicitly shown) and/or a slider to provide differential longitudinal movement versus the outer sheath  202 , which can sheathe and unsheathe the filter assembly  200  from the outer sheath  202 . 
     It is contemplated that the filter assembly  200  may further include one or more support elements or tines  214   a ,  214   b ,  214   c ,  214   d  (collectively,  214 ). The one or more tines  214  may extend distally from the filter wire  210  towards the filter frame  204 . For a proximally facing filter, the one or more tines  214  may extend proximally from a distal end of the filter towards the filter frame. It is contemplated that the one or more tines  214  may extend an entire length of the filter assembly  200  from the filter wire  210  to the filter frame  204  or less than an entire length between the filter wire  210  and the filter frame  204 . In some embodiments, the one or more tines  214  may extend 99% or less, 90% or less, 70% or less, 50% or less, 30% or less of the length between the filter wire  210  and the filter frame  204 . These are just some examples. The one or more tines  214  may extend over any length between the filter wire  210  and the filter frame  204 , as desired. In some embodiments, the tines  214  may be uniformly spaced at approximately equal intervals about the filter membrane  206 . In other embodiments, the tines  214  may be eccentrically positioned, as desired. It is further contemplated that the filter assembly  200  may include any number of tines  214 , such as, but not limited to, zero, one, two, three, four, five, six, or more. The tines  214  may be formed from a material that is more rigid than the filter element  206  such that the tines  214  provide additional structural support to the filter assembly  200 . 
     The delivery of the filter assembly  200  may be similar to the delivery of the filter assembly  66  described herein. In some methods of use, the filter assembly  200  may first be withdrawn into the outer sheath  202  to collapse (not explicitly shown) the filter assembly  200 . The outer sheath  202  may be advanced to the target location with or without a guidewire, as desired. The filter system  220  (e.g., filter assembly  200 , outer sheath  202 , and other delivery components) may be advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. However, the system  220  may be advanced using an access location desired, including, but not limited to left radial access, left brachial access, femoral access, etc. 
     When placing the system  220 , it may be desirable to avoid contact with the aortic valve to avoid damaging it. This may be accomplished by inserting a pigtail angiography catheter into the aortic arch through either a femoral access or through a left radial artery access, and injecting contrast so that the aortic valve may be located and imaged using fluoroscopy. However, it may be desired to not require the addition of femoral access for an angiography catheter given that femoral access is not required for all index procedure catheters, and femoral access is associated with increased access site vascular complications. It is contemplated that an angiography catheter (in some cases, a 4 Fr angiography catheter) may be advanced through an inner lumen of the outer sheath  202  and into the filter assembly  200  before or after deployment of the filter assembly  200 . Contrast may then be injected through the angiography catheter. In another embodiment, contrast may be injected directly through the guidewire lumen of an inner member (if so provided) or through the inner lumen of the outer sheath  202  if the inner member is removed. In yet another embodiment, contrast may not be used and the filter assembly  200  may be placed with imaging using transesophageal echocardiography (TEE). 
     Once the system  220  is in a desired position, the guidewire (if used) may then be proximally retracted. The system  220  may be delivered to the ascending aorta (see, for example,  FIG. 1 ) in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where the filter assembly  200  is in a collapsed configuration within the outer sheath  202 . The outer sheath  202  is retracted proximally to allow filter frame  204  to expand to an expanded configuration against the wall of the ascending aorta upstream of the ostium of the innominate artery. The filter element  206  is secured either directly or indirectly to support frame  204  and is therefore reconfigured to the configuration shown in  FIG. 3 . Alternatively, or additionally, the filter assembly  200  may be distally advanced from the outer sheath  202  through distal actuation of the filter wire  210 . Once expanded, the filter assembly  200  filters blood traveling through the ascending aorta, and therefore filters blood traveling into innominate artery, the right common carotid artery, the right vertebral artery  20 , the left common carotid artery  14 , the left subclavian artery  16 , the left vertebral artery, and the descending aorta. The expanded filter assembly  200  is therefore in position to prevent foreign particles from traveling into all four cerebral arteries, and into the cerebral vasculature. 
     The filter assembly  200  may be re-sheathed or positioned within the outer sheath  202  to facilitate repositioning of the filter assembly to optimize the placement of the filter assembly  200 . To re-sheathe the filter assembly  200 , it is contemplated that the outer sheath  202  may be distally advanced over the filter assembly  200 , the filter assembly  200  proximally retracted into the outer sheath via the filter wire  210 , or combinations thereof. The system  220  may then be repositioned and the filter assembly  200  redeployed. The filter assembly  200  may be re-sheathed, repositioned, and redeployed as many times as desired to optimize the placement of the filter assembly  200 . 
     Once the filter assembly  200  has been deployed, the index procedure (e.g., LAOO, TMVR, ablation, etc.) may then be performed. Following the completion of the index procedure, the filter assembly  200  may be sheathed (e.g., collapsed within the outer sheath  202 ) and the system  220  removed, with any captured debris removed along with the filter assembly  200 . 
       FIG. 4  is a partial perspective view of another illustrative filter assembly  300 . The filter assembly  300  may be configured to be advanced to a target location within an outer sheath  302  that may be similar in form and function to the outer sheath  52  described with respect to  FIG. 1 . The filter assembly  300  may include a support element or frame  304  and a filter element  308 . The frame  304  may be a hoop-like structure configured to generally provide expansion support to the filter element  308  in the expanded state. In the expanded state, the filter element  308  may be configured to filter fluid (e.g., blood) flowing through the filter element  308  and to inhibit or prevent particles (e.g., embolic material) from flowing through the filter element  308  by capturing the particles in the filter element  308 . 
     The frame  304  may be similar in form and function the frame  46  described herein and the filter element  308  may be similar in form and function to the filter element  50  described herein. For example, in some embodiments, the frame  304  comprises a straight piece of nitinol wire shape set into a circular or oblong hoop or hoop with one or two straight legs  312  running longitudinally along or at an angle to a longitudinal axis of the filter assembly  300 , although this is not required. At least one of the straight legs  312  may be coupled to a filter wire  310  or a strut. The straight legs  312  may be on a long side of the filter assembly  300  and/or on a short side of the filter assembly  300 . The frame  304  may form a shape of an opening  314  of the filter assembly  300 . The opening  314  may be circular, elliptical, or any shape that can appropriately appose sidewalls of a vessel. The filter assembly  300  may have a generally distally-facing opening  314 . In other embodiments, the opening  314  may be proximally facing. The orientation of the opening  314  may vary depending on where the access incision is located and/or the vessel in which the filter assembly  300  is to be positioned. 
     In some embodiments, the filter assembly  300  may include a second, or an additional hoop-like support structure  306 . The support structure  306  may have a curved distal end region  316  which extends about a portion of the circumference of the filter assembly  300  and a generally longitudinally extending proximal portion  318 . The proximal portion  318  may include pair of legs  320   a ,  320   b  (collectively,  320 ). A proximal portion of the legs  320  may be secured to the filter wire  310  while the distal ends of the legs  320  are interconnected by the distal portion  316  of the support structure  306 . The support structure  306  may be positioned proximal to the filter frame  304  to stiffen the filter element  308  and to ensure good expansion and apposition of the filter assembly  300 . However, other arrangements of the support structure  306  and/or the filter frame  304  are also contemplated. For example, in one embodiment, the support structure  306  may be positioned distal to the filter frame  304 . Alternatively, or additionally, the support structure  306  may have a helical or spring-like shape. 
     In some cases, the filter assembly  300  may include a self-expanding filter assembly (e.g., comprising a superelastic material with stress-induced martensite due to confinement in the outer sheath  302 ). The filter assembly  300  may comprise a shape-memory material configured to self-expand upon a temperature change (e.g., heating to body temperature). The filter assembly  300  may comprise a shape-memory or superelastic frame (e.g., comprising a distal end hoop comprising nitinol) and a microporous material (e.g., comprising a polymer including laser-drilled holes) coupled to the frame, for example similar to the filter assemblies described in U.S. Pat. No. 8,876,796. 
     The filter assembly  300  may be coupled (e.g., crimped, welded, soldered, etc.) to a distal end of a deployment wire or filter wire  310  via a strut or wire, such as, but not limited to the leg  312  and/or legs  320 , although this is not required. When both or all of the filter wire  310  and the strut are provided, the filter wire  310  and the strut may be coupled proximal to the filter assembly  300  using a crimp mechanism. In other embodiments, the filter wire  310  and the strut (or leg  312 ) may be a single unitary structure. The filter wire  310  and/or strut can comprise a rectangular ribbon, a round (e.g., circular, elliptical) filament, a portion of a hypotube, a braided structure (e.g., as described herein), combinations thereof, and the like. The filter wire  310  can be coupled to the handle (not explicitly shown) and/or a slider to provide differential longitudinal movement versus the outer sheath  302 , which can sheathe and unsheathe the filter assembly  300  from the outer sheath  302 . 
     The delivery of the filter assembly  300  may be similar to the delivery of the filter assembly  66  described herein. In some methods of use, the filter assembly  300  may first be withdrawn into the outer sheath  302  to collapse the filter assembly  300  (not explicitly shown). The outer sheath  302  may be advanced to the target location with or without a guidewire, as desired. The filter system  330  (e.g., filter assembly  300 , outer sheath  302 , and other delivery components) may be advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. However, the system  330  may be advanced using an access location desired, including, but not limited to left radial access, left brachial access, femoral access, etc. 
     When placing the system  330 , it may be desirable to avoid contact with the aortic valve to avoid damaging it. This may be accomplished by inserting a pigtail angiography catheter into the aortic arch through either a femoral access or through a left radial artery access, and injecting contrast so that the aortic valve may be located and imaged using fluoroscopy. However, it may be desired to not require the addition of femoral access for an angiography catheter given that femoral access is not required for all index procedure catheters, and femoral access is associated with increased access site vascular complications. It is contemplated that an angiography catheter (in some cases, a 4 Fr angiography catheter) may be advanced through an inner lumen of the outer sheath  302  and into the filter assembly  300  before or after deployment of the filter assembly  300 . Contrast may then be injected through the angiography catheter. In another embodiment, contrast may be injected directly through the guidewire lumen of an inner member (if so provided) or through the inner lumen of the outer sheath  302  if the inner member is removed. In yet another embodiment, contrast may not be used and the filter assembly  300  may be placed with imaging using transesophageal echocardiography (TEE). 
     Once the system  330  is in a desired position, the guidewire (if used) may then be proximally retracted. The system  330  may be delivered to the ascending aorta (see, for example,  FIG. 1 ) in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where the filter assembly  300  is in a collapsed configuration within the outer sheath  302 . The outer sheath  302  is retracted proximally to allow the filter frame  304  to expand to an expanded configuration against the wall of the ascending aorta upstream of the ostium of the innominate artery. The filter element  308  is secured either directly or indirectly to support frame  304  and is therefore reconfigured to the configuration shown in  FIG. 4 . Alternatively, or additionally, the filter assembly  300  may be distally advanced from the outer sheath  302  through distal actuation of the filter wire  310 . Once expanded, the filter assembly  300  filters blood traveling through the ascending aorta, and therefore filters blood traveling into innominate artery, the right common carotid artery  18 , the right vertebral artery, the left common carotid artery, the left subclavian artery, the left vertebral artery, and the descending aorta. The expanded filter assembly  300  is therefore in position to prevent foreign particles from traveling into all four cerebral arteries, and into the cerebral vasculature. 
     The filter assembly  300  may be re-sheathed or positioned within the outer sheath  302  to facilitate repositioning of the filter assembly to optimize the placement of the filter assembly  300 . To re-sheathe the filter assembly  300 , it is contemplated that the outer sheath  302  may be distally advanced over the filter assembly  300 , the filter assembly  300  proximally retracted into the outer sheath  302  via the filter wire  310 , or combinations thereof. The system  330  may then be repositioned and the filter assembly  300  redeployed. The filter assembly  300  may be re-sheathed, repositioned, and redeployed as many times as desired to optimize the placement of the filter assembly  300 . 
     Once the filter assembly  300  has been deployed, the index procedure (e.g., LAOO, TMVR, ablation, etc.) may then be performed. Following the completion of the index procedure, the filter assembly  300  may be sheathed (e.g., collapsed within the outer sheath  302 ) and the system  330  removed, with any captured debris removed along with the filter assembly  300 . 
       FIG. 5  is a schematic view of a portion of an aorta  10  including a filter assembly  400 . The filter assembly  400  may be configured to be advanced to the target location within an outer sheath  402  that may be similar in form and function to the outer sheath  52  described with respect to  FIG. 1 . The filter assembly  400  may include a support element or frame  404  and a filter element  406 . The frame  404  may be a hoop-like structure configured to generally provide expansion support to the filter element  406  in the expanded state. In the expanded state, the filter element  406  may be configured to filter fluid (e.g., blood) flowing through the filter element  406  and to inhibit or prevent particles (e.g., embolic material) from flowing through the filter element  406  by capturing the particles in the filter element  406 . 
     The frame  404  may be similar in form and function the frame  46  described herein and the filter element  406  may be similar in form and function to the filter element  50  described herein. For example, in some embodiments, the frame  404  comprises a straight piece of nitinol wire shape set into a circular or oblong hoop or hoop with one or more struts  408  extending between the hoop and a filter wire  412 . The strut  408  may be free from a coupling with the filter element  406  such that a portion of the filter element  406  is free to extend into the aortic arch  30  and possibly into the descending aorta  28  while the strut  408  remains coupled to an actuation mechanism (which may be the filter wire  412 ) within the outer sheath  402 , although this is not required. The frame  404  may form a shape of an opening  414  of the filter assembly  400 . The opening  414  may be circular, elliptical, or any shape that can appropriately appose sidewalls of a vessel. The filter assembly  400  may have a generally distally-facing opening  414 . In other embodiments, the opening  414  may be proximally facing. The orientation of the opening  414  may vary depending on where the access incision is located and/or the vessel in which the filter assembly  400  is to be positioned. 
     In some cases, the filter assembly  400  may include a self-expanding filter assembly (e.g., comprising a superelastic material with stress-induced martensite due to confinement in the outer sheath  402 ). The filter assembly  400  may comprise a shape-memory material configured to self-expand upon a temperature change (e.g., heating to body temperature). The filter assembly  400  may comprise a shape-memory or superelastic frame (e.g., comprising a distal end hoop comprising nitinol) and a microporous material (e.g., comprising a polymer including laser-drilled holes) coupled to the frame, for example similar to the filter assemblies described in U.S. Pat. No. 8,876,796. 
     The filter assembly  400  may be coupled (e.g., crimped, welded, soldered, etc.) to a distal end of a deployment wire or filter wire  412  via a strut or wire, such as, but not limited to the leg  408 , although this is not required. When both or all of the filter wire  412  and the strut are provided, the filter wire  412  and the strut may be coupled proximal to the filter assembly  400  using a crimp mechanism. In other embodiments, the filter wire  412  and the strut  408  may be a single unitary structure. The filter wire  412  and/or strut  408  can comprise a rectangular ribbon, a round (e.g., circular, elliptical) filament, a portion of a hypotube, a braided structure (e.g., as described herein), combinations thereof, and the like. The filter wire  412  can be coupled to the handle (not explicitly shown) and/or a slider to provide differential longitudinal movement versus the outer sheath  402 , which can sheathe and unsheathe the filter assembly  400  from the outer sheath  402 . 
     The filter element  406  may comprise a “wind sock” shaped filter bag, the proximal end region  416  or base of which can separate from the outer sheath  402  and/or filter wire  412  and extend into and/or across the aortic arch  30 . For example, the filter bag  406  may have a generally tubular shape with an enclosed proximal end region  416 . The number and location of filter holes in the filter element  406  may be varied in order to optimize the pressure gradient across the filter element  406  to ensure good wall apposition and sealing. In one embodiment, a tether  410  may extend distally from a proximal end of the outer sheath  402  (for example, from a handle) to the filter assembly  400 . A distal end of the tether  410  may be coupled to the base  416  of the filter element  406 . The tether  410  may be formed of woven suture material or the like. The material of the tether  410  may be such that the tether  410  may be tensioned during retrieval of the filter assembly  400  to pull the base  416  of the filter element  406  back into the outer sheath  402  in order to collapse the filter assembly  400  and prevent bunching of filter element  406  during retrieval. 
     The delivery of the filter assembly  400  may be similar to the delivery of the filter assembly  66  described herein. In some methods of use, the filter assembly  400  may first be withdrawn into the outer sheath  402  to collapse the filter assembly  400  (not explicitly shown). The outer sheath  402  may be advanced to the target location with or without a guidewire, as desired. The filter system  420  (e.g., filter assembly  400 , outer sheath  402 , and other delivery elements) may be advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. However, the system  420  may be advanced using an access location desired, including, but not limited to left radial access, left brachial access, femoral access, etc. 
     When placing the system  420 , it may be desirable to avoid contact with the aortic valve to avoid damaging it. This may be accomplished by inserting a pigtail angiography catheter into the aortic arch through either a femoral access or through a left radial artery access, and injecting contrast so that the aortic valve may be located and imaged using fluoroscopy. However, it may be desired to not require the addition of femoral access for an angiography catheter given that femoral access is not required for all index procedure catheters, and femoral access is associated with increased access site vascular complications. It is contemplated that an angiography catheter (in some cases, a 4 Fr angiography catheter) may be advanced through an inner lumen of the outer sheath  402  and into the filter assembly  400  before or after deployment of the filter assembly  400 . Contrast may then be injected through the angiography catheter. In another embodiment, contrast may be injected directly through the guidewire lumen of an inner member (if so provided) or through the inner lumen of the outer sheath  402  if the inner member is removed. In yet another embodiment, contrast may not be used and the filter assembly  400  may be placed with imaging using transesophageal echocardiography (TEE). 
     Once the system  420  is in a desired position, the guidewire (if used) may then be proximally retracted. The system  420  may be delivered to the ascending aorta  26  in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where the filter assembly  400  is in a collapsed configuration within the outer sheath  402 . The outer sheath  402  is retracted proximally to allow filter frame  404  to expand to an expanded configuration against the wall of the ascending aorta  26  upstream of the ostium of the innominate artery  12 . The filter element  406  is secured either directly or indirectly to support frame  404  and is therefore reconfigured to the configuration shown in  FIG. 5 . Alternatively, or additionally, the filter assembly  400  may be distally advanced from the outer sheath  402  through distal actuation of the filter wire  412 . Once expanded, the filter assembly  400  filters blood traveling through the ascending aorta  26 , and therefore filters blood traveling into innominate artery  12 , the right common carotid artery  18 , the right vertebral artery  20 , the left common carotid artery  14 , the left subclavian artery  16 , the left vertebral artery  24 , and the descending aorta  28 . The expanded filter assembly  400  is therefore in position to prevent foreign particles from traveling into all four cerebral arteries  14 ,  18 ,  20 ,  24 , and into the cerebral vasculature. 
     The filter assembly  400  may be re-sheathed or positioned within the outer sheath  402  to facilitate repositioning of the filter assembly to optimize the placement of the filter assembly  400 . To re-sheathe the filter assembly  400 , it is contemplated that the outer sheath  402  may be distally advanced over the filter assembly  400 , the filter assembly  400  proximally retracted into the outer sheath via the filter wire  408 , or combinations thereof. The system  420  may then be repositioned and the filter assembly  400  redeployed. The filter assembly  400  may be re-sheathed, repositioned, and redeployed as many times as desired to optimize the placement of the filter assembly  400 . 
     Once the filter assembly  400  has been deployed, the index procedure (e.g., LAOO, TMVR, ablation, etc.) may then be performed. Following the completion of the index procedure, the filter assembly  400  may be sheathed (e.g., collapsed within the outer sheath  402 ) and the system  420  removed, with any captured debris removed along with the filter assembly  400 . 
       FIG. 6  is a partial perspective view of another illustrative filter assembly  500 . The filter assembly  500  may be configured to be advanced to the target location within an outer sheath  502  that may be similar in form and function to the outer sheath  52  described with respect to  FIG. 1 . The filter assembly  500  may include an elongated tubular body  504 . While the filter assembly  500  is described as generally tubular, it is contemplated that the filter assembly  500  may take any cross-sectional shape desired. The filter assembly  500  may have a first, or proximal end  506 , a second, or distal end  508 , and an intermediate region  510  disposed between the first end  506  and the second end  508 . The filter assembly  500  may include a cavity  512  extending from an opening adjacent the distal end  508  to the proximal end  506 . The proximal end  506  may be enclosed to trap particles within the cavity  512 . 
     The filter assembly  500  may be expandable from a first radially collapsed configuration (not explicitly shown) to a second radially expanded configuration. In some cases, the filter assembly  500  may be deployed to a configuration between the collapsed configuration and a fully expanded configuration. In the expanded state, the tubular body  504  may be configured to filter fluid (e.g., blood) flowing through the tubular body  504  and to inhibit or prevent particles (e.g., embolic material) from flowing through the tubular body  504  by capturing the particles in the tubular body  504 . The tubular body  504  may have a woven structure, fabricated from a number of filaments. In some embodiments, the tubular body  504  may be braided with one filament. In other embodiments, the tubular body  504  may be braided with several filaments. In another embodiment, the tubular body  504  may be knitted. In yet another embodiment, the tubular body  504  may be of a knotted type. In still another embodiment, the tubular body  504  may be laser cut. 
     In some embodiments, the tubular body  504  may be self-expanding (e.g., comprising a superelastic material with stress-induced martensite due to confinement in the outer sheath  502 ). The filter assembly  500  may comprise a shape-memory material configured to self-expand upon a temperature change (e.g., heating to body temperature). The filter assembly  500  may comprise a shape-memory or superelastic frame (e.g., comprising a distal end hoop comprising nitinol). The tubular body  504  may be woven, braided, knitted, knotted laser drilled, etc. such that the space between adjacent filaments (or other openings formed therein) are small enough to inhibit or prevent particles (e.g., embolic material) from flowing through the tubular body  504  by capturing the particles in the tubular body  504 . 
     In some embodiments, the distal end  508  may have an outer diameter that is larger than an outer diameter of the intermediate region  510  and/or the proximal end  506 . This may help provide good apposition with the wall when the filter assembly  500  is deployed. However, this is not required. In other embodiments, the distal end  508  and the intermediate region  510  may have a substantially uniform outer diameter. It is contemplated that the proximal end  506  may have a reduced diameter relative to the remaining portions of the tubular body  504  to create an enclosed end to trap the particles. 
     It is contemplated that the distal end  508  of the tubular body  504  may be sharp or jagged when wire filaments are used to form the tubular body  504 . It is contemplated that the distal end  508  may include a polymer coating, such as but not limited to, polyurethane or silicone, to limit damage to the vasculature during deployment. Alternatively, or additionally, the distal end  508  may be folded back over itself to form a hem  516 . The hem  516  may be mechanically secured using sutures, adhesives, etc., if so desired. 
     The filter assembly  500  may be coupled (e.g., crimped, welded, soldered, etc.) to a distal end of a deployment wire or filter wire  514 . The filter wire  514  can comprise a rectangular ribbon, a round (e.g., circular, elliptical) filament, a portion of a hypotube, a braided structure (e.g., as described herein), combinations thereof, and the like. The filter wire  514  can be coupled to a handle (not explicitly shown) and/or a slider to provide differential longitudinal movement versus the outer sheath  502 , which can sheathe and unsheathe the filter assembly  500  from the outer sheath  502 . 
     The delivery of the filter assembly  500  may be similar to the delivery of the filter assembly  66  described herein. In some methods of use, the filter assembly  500  may first be withdrawn into the outer sheath  502  to collapse the filter assembly  500  (not explicitly shown). The outer sheath  502  may be advanced to the target location with or without a guidewire, as desired. The filter system  520  (filter assembly  500 , outer sheath  502 , and other delivery components) may be advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. However, the system  520  may be advanced using an access location desired, including, but not limited to left radial access, left brachial access, femoral access, etc. 
     When placing the system  520 , it may be desirable to avoid contact with the aortic valve to avoid damaging it. This may be accomplished by inserting a pigtail angiography catheter into the aortic arch through either a femoral access or through a left radial artery access, and injecting contrast so that the aortic valve may be located and imaged using fluoroscopy. However, it may be desired to not require the addition of femoral access for an angiography catheter given that femoral access is not required for all index procedure catheters, and femoral access is associated with increased access site vascular complications. It is contemplated that an angiography catheter (in some cases, a 4 Fr angiography catheter) may be advanced through an inner lumen of the outer sheath  502  and into the filter assembly  500  before or after deployment of the filter assembly  500 . Contrast may then be injected through the angiography catheter. In another embodiment, contrast may be injected directly through the guidewire lumen of an inner member (if so provided) or through the inner lumen of the outer sheath  502  if the inner member is removed. In yet another embodiment, contrast may not be used and the filter assembly  500  may be placed with imaging using transesophageal echocardiography (TEE). 
     Once the system  520  is in a desired position, the guidewire (if used) may then be proximally retracted. The system  520  may be delivered to the ascending aorta (see, for example,  FIG. 1 ) in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where the filter assembly  500  is in a collapsed configuration within the outer sheath  502 . The outer sheath  502  is retracted proximally to allow the tubular body  504  to expand to an expanded configuration against the wall of the ascending aorta upstream of the ostium of the innominate artery. Alternatively, or additionally, the filter assembly  500  may be distally advanced from the outer sheath  502  through distal actuation of the filter wire  514 . Once expanded, the filter assembly  500  filters blood traveling through the ascending aorta, and therefore filters blood traveling into innominate artery, the right common carotid artery, the right vertebral artery, the left common carotid artery, the left subclavian artery, the left vertebral artery, and the descending aorta. The expanded filter assembly  500  is therefore in position to prevent foreign particles from traveling into all four cerebral arteries, and into the cerebral vasculature. 
     The filter assembly  500  may be re-sheathed or positioned within the outer sheath  502  to facilitate repositioning of the filter assembly  500  to optimize the placement of the filter assembly  500 . To re-sheathe the filter assembly  500 , it is contemplated that the outer sheath  502  may be distally advanced over the filter assembly  500 , the filter assembly  500  proximally retracted into the outer sheath  502  via the filter wire  514 , or combinations thereof. The system  520  may then be repositioned and the filter assembly  500  redeployed. The filter assembly  500  may be re-sheathed, repositioned, and redeployed as many times as desired to optimize the placement of the filter assembly  500 . 
     Once the filter assembly  500  has been deployed, the index procedure (e.g., LAOO, TMVR, ablation, etc.) may then be performed. Following the completion of the index procedure, the filter assembly  500  may be sheathed (e.g., collapsed within the outer sheath  502 ) and the system  520  removed, with any captured debris removed along with the filter assembly  500 . 
       FIG. 7  is a schematic view of another illustrative filter assembly  600  positioned within the ascending aorta  26 . The filter assembly  600  may be configured to be advanced to the target location within an outer sheath  602  that may be similar in form and function to the outer sheath  52  described with respect to  FIG. 1 . The filter assembly  600  may include a variable diameter support element or frame  604  and a filter element  606 . The frame  604  may be an expandable structure configured to generally provide expansion support to the filter element  606  in the expanded state. In the expanded state, the filter element  606  may be configured to filter fluid (e.g., blood) flowing through the filter element  606  and to inhibit or prevent particles (e.g., embolic material) from flowing through the filter element  606  by capturing the particles in the filter element  606 . The filter element  606  may be similar in form and function to the filter element  50  described herein. While not explicitly shown, the filter assembly  600  may include any of the additional support elements described herein, such as, but not limited to, one or more longitudinally extending tines, an elongated hoop, a hemmed terminal end, etc. It is further contemplated that the filter assembly  600  may include a tether coupled to the base of the filter element  606  such that the base may be drawn into the outer sheath  602  upon actuation of the tether. 
     The frame  604  may be formed from an inflatable fabric or polymer tube. The frame  604  may be expandable from a first collapsed configuration to a second expanded configuration through the injection of an inflation media into a sealable and enclosed inflation cavity  610  in the frame  604  such that the diameter of the frame  604  is variable. For example, the diameter can be increased by injection more inflation fluid and reduced by removing inflation fluid (or injecting less). The inflation cavity  610  may receive an inflation fluid from an inflation fluid source through an inflation port or valve  612  to expand the frame  604  from a generally collapsed delivery configuration (not explicitly shown) to an expanded or deployed configuration (as shown in  FIG. 7 ). The inflation fluid may be saline, a biocompatible liquid polymer, such as ENTERYX®, air, or other suitable inflation fluid. 
     While the frame  604  is illustrated as having an undulating configuration, other configuration as also contemplated. For example, the frame  604  may take the form of a ring or hoop. Alternatively or additionally, the frame  604  may include longitudinally extending portions. In some instances, the frame  604  may be a helical frame, winding about the circumference of filter assembly  600  from a first end  614  to a second end  616 . It is contemplated that a plurality of inflation chambers may be fluidly connected to allow a single inflation valve  612  to provide an inflation fluid to each of the chambers. However, this is not required. A plurality of inflation valves may be provided to supply each of the inflation chambers, individually or in groups, with an inflation fluid. These are just examples. 
     The inflation valve  612  may be in fluid communication with the inflation cavity  610  to provide a regulated passage for an inflation fluid to travel into the inflation cavity  610  of the frame  604 . The inflation valve  612  may be any of a number of widely applied valves, applicable in surgeries and medical implants, and may be made from a biocompatible material. In some embodiments, the inflation valve  612  may be a unidirectional, or one-way, valve that provides a regulated passage for an amount of a suitable fluid into the inflation cavity  610  of the inflatable frame  604 . For example, the inflation valve  612  may provide such a passage upon an application of pressure from a catheter lumen or an inflation device that is introduced into the frame  604  for the stent&#39;s inflation. Once the application of pressure is removed, a diaphragm or other sealing mechanism may seal the inflation cavity  610  to maintain the frame  604  in the inflated state. However, this is not required. In some embodiments, inflation fluid may be continually supplied to the inflation cavity  610  to maintain the frame  604  in an expanded configuration. For example, inflation fluid may be continuously delivered to the inflation cavity  610  via a constant pressure source. For example, inflation fluid may be continuously delivered to maintain a measured pressure at a constant (or approximately constant value). Such a system may help maintain apposition of the frame  604  with a vessel wall if there is compliance and/or stretching in the frame  604  over the course of the procedure. 
     The inflation cavity  610  and/or inflation valve  612  may be in fluid communication with an inflation fluid source via an inflation lumen  608 . The inflation lumen  608  may be a dedicated lumen extending proximally from the inflation cavity  610  to the proximal end region of the system  630  for receiving the inflation fluid. It is contemplated that the inflation fluid may be injected from a handle, through the inflation lumen  608  and to the inflation cavity  610  to expand the frame  604  and seal it against the vessel wall. In some embodiments, suction may be applied to the inflation lumen  608  to remove the inflation fluid from the inflation cavity  610  and collapse the frame  604 . This may be performed to reposition and/or remove the filter assembly  600 . 
     In some embodiments, the filter assembly  600  may be coupled to an elongate shaft and/or filter wire  618  adjacent to the first end  614  of the filter assembly  600 . It is contemplated that the inflation lumen  608  may extend within the elongate shaft  618  or alongside the elongate shaft  618 , as desired. The elongate shaft  618  can be coupled to a handle (not explicitly shown) and/or a slider to provide differential longitudinal movement versus the outer sheath  602 , which can sheathe and unsheathe the filter assembly  600  from the outer sheath  602 . 
     The frame  604  may form a shape of an opening  620  of the filter assembly  600 . The opening  620  may be circular, elliptical, or any shape that can appropriately appose sidewalls of a vessel. The filter assembly  600  may have a generally distally-facing opening  620 . In other embodiments, the opening  620  may be proximally facing. The orientation of the opening  620  may vary depending on where the access incision is located and/or the vessel in which the filter assembly  600  is to be positioned. 
     The delivery of the filter assembly  600  may be similar to the delivery of the filter assembly  66  described herein. In some methods of use, the filter assembly  600  may first be withdrawn into the outer sheath  602  for delivery. The outer sheath  602  may be advanced to the target location with or without a guidewire, as desired. The filter system  630  (filter assembly  600 , outer sheath  602 , and other delivery components) may be advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. However, the system  630  may be advanced using an access location desired, including, but not limited to left radial access, left brachial access, femoral access, etc. 
     When placing the system  630 , it may be desirable to avoid contact with the aortic valve to avoid damaging it. This may be accomplished by inserting a pigtail angiography catheter into the aortic arch through either a femoral access or through a left radial artery access, and injecting contrast so that the aortic valve may be located and imaged using fluoroscopy. However, it may be desired to not require the addition of femoral access for an angiography catheter given that femoral access is not required for all index procedure catheters, and femoral access is associated with increased access site vascular complications. It is contemplated that an angiography catheter (in some cases, a 4 Fr angiography catheter) may be advanced through an inner lumen of the outer sheath  602  and into the filter assembly  600  before or after deployment of the filter assembly  600 . Contrast may then be injected through the angiography catheter. In another embodiment, contrast may be injected directly through the guidewire lumen of an inner member (if so provided) or through the inner lumen of the outer sheath  602  if the inner member is removed. In yet another embodiment, contrast may not be used and the filter assembly  600  may be placed with imaging using transesophageal echocardiography (TEE). 
     Once the system  630  is in a desired position, the guidewire (if used) may then be proximally retracted. The system  630  may be delivered to the ascending aorta  26  in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where the filter assembly  600  is in a collapsed configuration within the outer sheath  602 . The outer sheath  602  is retracted proximally and inflation fluid is injected into the inflation cavity  610  to allow filter frame  604  to expand to an expanded configuration against the wall of the ascending aorta  26  upstream of the ostium of the innominate artery  12 . The filter element  606  is secured either directly or indirectly to support frame  604  and is therefore reconfigured to the configuration shown in  FIG. 7 . Alternatively, or additionally, the filter assembly  600  may be distally advanced from the outer sheath  602  through distal actuation of the elongate shaft  618  and inflation fluid delivered to the inflation cavity  610 . Once expanded, the filter assembly  600  filters blood traveling through the ascending aorta  26 , and therefore filters blood traveling into innominate artery  12 , the right common carotid artery  18 , the right vertebral artery  20 , the left common carotid artery  14 , the left subclavian artery  16 , the left vertebral artery  24 , and the descending aorta  28 . The expanded filter assembly  600  is therefore in position to prevent foreign particles from traveling into all four cerebral arteries  14 ,  18 ,  20 ,  24 , and into the cerebral vasculature. 
     The filter assembly  600  may be re-sheathed or positioned within the outer sheath  602  to facilitate repositioning of the filter assembly to optimize the placement of the filter assembly  600 . To re-sheathe the filter assembly  600 , it is contemplated that the inflation fluid is removed from the inflation cavity  610  and the outer sheath  602  distally advanced over the filter assembly  600 , the filter assembly  600  proximally retracted into the outer sheath via the elongate shaft  618 , or combinations thereof. The system  630  may then be repositioned and the filter assembly  600  redeployed. The filter assembly  600  may be re-sheathed, repositioned, and redeployed as many times as desired to optimize the placement of the filter assembly  600 . 
     Once the filter assembly  600  has been deployed, the index procedure (e.g., LAOO, TMVR, ablation, etc.) may then be performed. Following the completion of the index procedure, the filter assembly  600  may be sheathed (e.g., collapsed within the outer sheath  602 ) and the system  630  removed, with any captured debris removed along with the filter assembly  600 . 
       FIG. 8  is a partial schematic view of another illustrative filter assembly  700 . The filter assembly  700  may be configured to be advanced to the target location within an outer sheath  716  that may be similar in form and function to the outer sheath  52  described with respect to  FIG. 1 . The filter assembly  700  may include a support element or frame  702  and a filter element  704 . The frame  702  may be an expandable structure configured to generally provide expansion support to the filter element  704  in the expanded state. In the expanded state, the filter element  704  may be configured to filter fluid (e.g., blood) flowing through the filter element  704  and to inhibit or prevent particles (e.g., embolic material) from flowing through the filter element  704  by capturing the particles in the filter element  704 . The filter element  704  may be similar in form and function to the filter element  50  described herein. While not explicitly shown, the filter assembly  700  may include any of the additional support elements described herein, such as, but not limited to, one or more longitudinally extending tines, an elongated hoop, a hemmed terminal end, etc. It is further contemplated that the filter assembly  700  may include a tether coupled to the base of the filter element  704  such that the base may be drawn into the outer sheath  716  upon actuation of the tether. 
     In some embodiments, the frame  702  may be self-expanding (e.g., comprising a superelastic material with stress-induced martensite due to confinement in the outer sheath  716 ). The filter assembly  700  may comprise a shape-memory material configured to self-expand upon a temperature change (e.g., heating to body temperature). The filter assembly  700  may comprise a shape-memory or superelastic frame (e.g., comprising a distal end hoop comprising nitinol). The frame  702  may be formed from an open spaced coil including a plurality of windings  708  which can be expanded or contracted to change a diameter  710  of the opening  712  of the frame  702  such that the diameter of the frame  702  is variable. Alternatively, the frame  702  may be formed from a laser cut tube having a plurality of openings. The frame  702  may have a generally circular shape. A flexible tension element  706  may be extend through or be threaded through a central lumen of the frame  702 . For example, when the frame  702  includes a plurality of windings, the flexible tension element  706  may be extend through or be threaded within a center of the plurality of windings  708 . A distal end of the flexible tension element  706  may be fixedly coupled to the frame  702  such that a proximal or pulling force  714  applied to a proximal end of the tension element  706  (the proximal end extending proximally from the frame  702  and configured to remain outside the body) exerts a radially inward force of the frame and draws the windings  708  closer together to reduce the diameter  710  of the frame  702 . The diameter  710  of the frame  702  may be increased by relaxing tension on the flexible tension element  706  to allow the frame  702  to expand. It is contemplated that the pitch of the coil or laser cut element can vary such that different regions will elongate or foreshorten as the internal tension element  706  is adjusted by the operator resulting in a more optimal seal against the vessel wall. In some embodiments, the internal tension element  706  may be coupled to a device configured to exert a constant or nearly constant pressure on the internal tension element  706 . For example, the internal tension element  706  may be coupled to a spring in a handle, or other mechanism, configured to achieve a nearly constant pressure on the internal tension element  706 . 
     In some embodiments, the filter assembly  700  may be coupled to the tension element  706 . The tension element  706  can be coupled to a handle (not explicitly shown) and/or a slider to provide differential longitudinal movement versus the outer sheath  716 , which can sheathe and unsheathe the filter assembly  700  from the outer sheath  716 . In other embodiments, a filter wire (not explicitly shown) may be coupled to the filter assembly  700  to actuate the filter assembly  700  in a proximal and/or distal direction while the tension element  706  is actuated to control a diameter  710  of the filter frame  702 . 
     The frame  702  may form a shape of an opening  712  of the filter assembly  700 . The opening  712  may be circular, elliptical, or any shape that can appropriately appose sidewalls of a vessel. The filter assembly  700  may have a generally distally-facing opening  712 . In other embodiments, the opening  712  may be proximally facing. The orientation of the opening  712  may vary depending on where the access incision is located and/or the vessel in which the filter assembly  700  is to be positioned. 
     The delivery of the filter assembly  700  may be similar to the delivery of the filter assembly  66  described herein. In some methods of use, the filter assembly  700  may first be withdrawn into the outer sheath  716  for delivery. The outer sheath  716  may be advanced to the target location with or without a guidewire, as desired. The filter system  720  (filter assembly  700 , outer sheath  716 , and other delivery components) may be advanced into the subject through an incision made in the subject&#39;s right radial artery, or alternatively the right brachial artery. However, the system  720  may be advanced using an access location desired, including, but not limited to left radial access, left brachial access, femoral access, etc. 
     When placing the system  720 , it may be desirable to avoid contact with the aortic valve to avoid damaging it. This may be accomplished by inserting a pigtail angiography catheter into the aortic arch through either a femoral access or through a left radial artery access, and injecting contrast so that the aortic valve may be located and imaged using fluoroscopy. However, it may be desired to not require the addition of femoral access for an angiography catheter given that femoral access is not required for all index procedure catheters, and femoral access is associated with increased access site vascular complications. It is contemplated that an angiography catheter (in some cases, a 4 Fr angiography catheter) may be advanced through an inner lumen of the outer sheath  716  and into the filter assembly  700  before or after deployment of the filter assembly  700 . Contrast may then be injected through the angiography catheter. In another embodiment, contrast may be injected directly through the guidewire lumen of an inner member (if so provided) or through the inner lumen of the outer sheath  716  if the inner member is removed. In yet another embodiment, contrast may not be used and the filter assembly  700  may be placed with imaging using transesophageal echocardiography (TEE). 
     Once the system  720  is in a desired position, the guidewire (if used) may then be proximally retracted. The system  720  may be delivered to the ascending aorta (see, for example,  FIG. 1 ) in a delivery configuration. The system&#39;s delivery configuration generally refers to the configuration where the filter assembly  700  is in a collapsed configuration within the outer sheath  716 . The outer sheath  716  is retracted proximally and the filter frame  702  to expands to an expanded configuration against the wall of the ascending aorta upstream of the ostium of the innominate artery. A proximal force may be exerted on the tension element  706  to reduce the diameter  710  of the opening or a distal pushing force exerted (or the proximal force simply removed) on the tension element  706  to increase the diameter  710  of the opening  712 . The filter element  704  is secured either directly or indirectly to support frame  702  and is therefore reconfigured to the configuration shown in  FIG. 8 . Alternatively, or additionally, the filter assembly  700  may be distally advanced from the outer sheath  716  through distal actuation of the filter wire. Once expanded, the filter assembly  700  filters blood traveling through the ascending aorta, and therefore filters blood traveling into innominate artery, the right common carotid artery, the right vertebral artery, the left common carotid artery, the left subclavian artery, the left vertebral artery, and the descending aorta. The expanded filter assembly  700  is therefore in position to prevent foreign particles from traveling into all four cerebral arteries, and into the cerebral vasculature. 
     The filter assembly  700  may be re-sheathed or positioned within the outer sheath  716  to facilitate repositioning of the filter assembly to optimize the placement of the filter assembly  700 . To re-sheathe the filter assembly  700 , it is contemplated that the outer sheath  716  may be distally advanced over the filter assembly  700 , the filter assembly  700  proximally retracted into the outer sheath  716  via the filter wire, or combinations thereof. The system  720  may then be repositioned and the filter assembly  700  redeployed. The filter assembly  700  may be re-sheathed, repositioned, and redeployed as many times as desired to optimize the placement of the filter assembly  700 . 
     Once the filter assembly  700  has been deployed, the index procedure (e.g., LAOO, TMVR, ablation, etc.) may then be performed. Following the completion of the index procedure, the filter assembly  700  may be sheathed (e.g., collapsed within the outer sheath  716 ) and the system  720  removed, with any captured debris removed along with the filter assembly  700 . 
     While the methods and devices described herein may be susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are described in detail herein. It should be understood, however, that the inventive subject matter is not to be limited to the particular forms or methods disclosed, but, to the contrary, covers all modifications, equivalents, and alternatives falling within the spirit and scope of the various implementations described and the appended claims. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with an implementation or embodiment can be used in all other implementations or embodiments set forth herein. In any methods disclosed herein, the acts or operations can be performed in any suitable se and are not necessarily limited to any particular disclosed sequence and not be performed in the order recited. Various operations can be described as multiple discrete operations in turn, in a manner that can be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures described herein can be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, embodiments can be carried out in a manner that achieves or optimizes one advantage or group of advantages without necessarily achieving other advantages or groups of advantages. The methods disclosed herein may include certain actions taken by a practitioner; however, the methods can also include any third-party instruction of those actions, either expressly or by implication. For example, actions such as “deploying a self-expanding filter” include “instructing deployment of a self-expanding filter.” The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between,” and the like includes the number recited. Numbers preceded by a term such as “about” or “approximately” include the recited numbers and should be interpreted based on the circumstances (e.g., as accurate as reasonably possible under the circumstances, for example ±5%, ±10%, ±15%, etc.). For example, “about 7 mm” includes “7 mm.” Phrases preceded by a term such as “substantially” include the recited phrase and should be interpreted based on the circumstances (e.g., as much as reasonably possible under the circumstances). For example, “substantially straight” includes “straight.” 
     Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.