Filter device and method

Abstract

Aspects of the present disclosure relate to devices and / or methods that include an asymmetric frame connected to extension arms and a filter having opposing surface regions that terminate at a periphery of the filter, the filter configured and arranged with the frame and extension arms to conform one of the opposing surface regions to an inner wall of a tubular structure.

Description

Technical Field

[0001] Various embodiments are directed to an apparatus and method including a filter for filtering fluid passing through a tubular structure.

Background Art

[0002] Various techniques for filtering a tubular structure such as a pipe-like structure having an opening in a side wall and its related structures are in practical use in many applications. Also, various treatments are useful for treating various medical conditions such as coronary artery disease, aneurysms, etc. These treatments often involve medical interventions such as tissue removal, repair, or treatment. For example, coronary artery disease sometimes accompanies valvular heart disease, which can be treated by medical intervention techniques for repairing or replacing the valve.

[0003] One useful means for treating various conditions involves inserting a catheter-like structure into a fluid conduit such as a patient's artery and providing various techniques. For example, various techniques such as tissue repair or removal or implantation of tissue or other devices can be performed via a catheter. Other techniques can be used to filter flow in other tubular structures such as pipes (e.g., preventing microparticles moving in a large pipe from entering a small pipe through the side wall of the pipe). One technique for treating heart disease is transcatheter aortic valve implantation or placement (TAVR / TAVI). These and other transcatheter methods involve delivering an artificial or animal valve / cap to a patient's heart via a catheter.

[0004] While many therapies are useful, they have numerous safety issues. For example, it is common to introduce, combine, and exchange various percutaneous devices such as guidewires, catheters, sheaths, guiding catheters, or other accessory techniques to reach and treat coronary vessels, coronary valves, or other vascular tissues. These and other techniques for tissue repair or replacement can move particles / fragments (emboli) that have become free from the vessel wall and structure, and the floating emboli will move freely uncontrollably and unprotectedly. This freedom and the freely floating and uncontrollable emboli are carried far away (separated) by the blood flow, causing problems such as occluding coronary vessels, peripheral vessels, and neurovascular vessels. For example, in the (TAVR / TAVI) procedure, the native tissue is compressed within the aortic wall, creating a space for the device to replace it. This action can move or displace plaques, calcium, or thrombus in the arterial wall when the device crosses the aortic arch. These particles can cause adverse effects such as strokes. These and other problems have posed difficulties for various treatments.

[0005] Examples of various embodiments are directed to filter devices and their implementation. According to a particular embodiment, the device comprises a frame and a filter, and the filter has an opposing surface region that is coupled to the periphery of the filter. Extended arms may be connected to the filter. The filter is configured and arranged with the frame (and, if possible, the extended arms) to adapt one of the opposing surface regions to the inner wall of the tubular structure by engaging the extended arms with each surface of the inner wall of the tubular structure. The frame may exhibit characteristics of asymmetry and / or varying flexibility that facilitate the adaptation of the frame to the inner wall and its associated features.

[0006] According to an example of an embodiment, the apparatus and / or method comprises an extension arm, a frame connected to the extension arm, a filter having an opposing surface region and coupled to or terminating at the periphery of the filter, and a filter. The filter is connected to the frame at its periphery and expands with the frame in the deployed state, and in the deployed state, the extension arm engages each surface of the inner wall of the tubular organ, and by applying a force to seal the periphery of the filter and the frame against the inner wall by the engagement, one of the opposing surface regions is configured and arranged to conform to the inner wall of the tubular organ. The apparatus may be implemented as part of a catheter and may be operated to expand when extending from the sheath and collapse (and, for example, capture particles within the filter) to contract into the sheath. A wire or other control mechanism extending within the sheath may be implemented to control the expansion / contraction and conformity of the filter.

[0007] Various embodiments are directed to an embolic protection device designed to protect the brain from stroke during left heart procedures such as those involving TAVR. The functional aspects of the dynamic two-end sealing of the device are facilitated by the behavior of the system during the cardiac output cycle and control over the accurate and predictable filter behavior before and after deployment.

[0008] Various embodiments may be implemented by an apparatus comprising a catheter extending from a proximal end to a distal end, a shaft present within the catheter and operable to move within the catheter, and a filter member connected to the shaft and operable to contract within the distal end of the catheter. The filter member comprises a filter such as a mesh, and inner and outer frames connected by struts, and the extension arm is connected to the frame. The periphery of the filter is coupled to the inner frame (in some cases, the outer frame), and the inner and outer frames extend relative to each other. The struts are operable to transmit a force applied via the extension arm, such as by applying a force to apply the inner frame and the mesh against the tissue (e.g., within vascular tissue), between the outer frame and the inner frame.

[0009] In various embodiments, a catheter comprising a frame, a filter, and an extension arm as described herein is inserted into the human aortic arch, and the filter member is deployed over at least one arterial opening within the aortic arch. The filter material is sealed to a portion of the inner wall of the aortic arch around at least one arterial opening and is used to capture particles within the blood flow entering the at least one arterial opening. In further embodiments, the filter material, frame, and struts collapse with the particles trapped therein, and the mesh, frame, struts, and particles can be collapsed within the catheter and then removed.

[0010] The above description / summary is not intended to describe every embodiment and all examples of the present disclosure. Various embodiments are also illustrated by the following drawings and detailed description.

[0011] Examples of various embodiments can be more fully understood by considering the following detailed description while referring simultaneously to the accompanying drawings in conjunction with the separate listing below.

Brief Description of the Drawings

[0012]

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[0013] Regarding the various embodiments described herein, changes and alternative forms are possible, and such aspects are illustrated in the drawings and described in detail. However, the present invention is not intended to be limited to the specific embodiments described below. On the other hand, the present invention encompasses all applications, equivalents, and alternatives within the technical scope of the present disclosure, including the technical scope defined by the claims. Also, the term "example" used herein is for illustrative purposes and not for limiting purposes.

Embodiments for Carrying Out the Invention

[0014] Aspects of the present disclosure are applicable to a variety of different types of devices, systems, and methods that include filters and can be disposed in a tubular structure. In some embodiments, catheter-based devices and methods may be used for such an arrangement. Various exemplary embodiments are directed to filtering blood flow to vascular tissue and are useful for capturing particles while maintaining blood flow. In certain embodiments, the device comprises a filter-type material connected to a frame that filters particles from the blood flow. The extension arm or shaft applies a force to the frame and operates to seal the frame and the filter-type material to a surface such as the inner wall of a blood vessel. In the context of these and other embodiments, it has been recognized / discovered that the use of the frame and the extension arm facilitates sealing the frame and the filter to the side wall, and that this approach is particularly useful for conforming and sealing the filter around the opening of the vascular tissue. Further, an asymmetric configuration of the frame can be utilized to provide lateral flexibility to accommodate various structural variations, such as mimicking (or being) the changes in the human body structure (e.g., aortic arch). Accordingly, these techniques can be used to reduce the passage of particles into the opening, which is particularly useful in surgical procedures. Further, by utilizing a rigid configuration, the filter is accurately sealed to the side wall without necessarily blocking or filtering the substances flowing within the blood vessel itself. The rigidity may vary across the frame and / or the extension arm and facilitates applying the desired force and sealing the filter. Without limitation, various aspects can be understood by using this present context for illustration.

[0015] According to one or more embodiments, the device comprises a frame and a filter having an opposite surface region and coupled to the periphery of the filter. The filter and the frame operate to adapt one of the opposite surface regions to the inner wall of the tubular structure by engaging the extending arms with each surface of the inner wall of the tubular structure and applying a force by the engagement to seal the periphery of the filter and the frame to the inner wall. The frame and the filter adapt to the inner wall and exhibit sufficient rigidity to seal the filter to the opening around the inner wall, if possible. Further, the frame and the filter may be configured to collapse and retract into the catheter-type structure for removal (and capture of particles trapped within the filter).

[0016] In various embodiments, the frame has an asymmetric configuration that facilitates engagement with a particular tubular structure. For example, referring to a tubular structure having the shape of the aortic arch of the human body, the frame exhibits various bending radii and can extend from the proximal end to the distal end such that both ends thereof are laterally displaced (e.g., with respect to the catheter shaft on which the frame is disposed). The bending radii facilitate lateral displacement from the centerline of different catheter shafts in different directions and may be asymmetric in one or both of the lateral and longitudinal directions.

[0017] The shaft may be connected to the extending arms and operate to slide within the catheter and apply a force to the frame to position the frame and the filter with respect to the inner wall of the tubular structure (and at that location, the extending arms connect the shaft and the frame). Further, the shaft may be operable to crush the frame and the filter into a collapsed state and retract them into the catheter. Thereby, capture and removal of particles that have moved, such as during mechanical operation of a surgical procedure, etc., can be facilitated. For example, with the filter sealed to the opening of the side wall of the aortic arch, a portion of the filter facing the inner region of the aortic arch can capture particles from the blood flowing through the filter through the side wall and then these particles can be removed.

[0018] Various embodiments are directed to an apparatus comprising a frame and a filter coupled to the frame, the frame having a continuous perimeter of an asymmetric shape with respect to one or both of a horizontal or vertical axis as viewed in a plane (or, e.g., from above at the point of implementation). Such an approach is implemented with a frame having a wide distal end and a narrow proximal end, an inner bend on the posterior side of a central region, and an outer bend on the anterior side, with the distance between the posterior frame rail of the proximal end of the frame and the centerline being less than the distance between the anterior frame rail of the distal end of the frame and the centerline. For example, if the central region is narrower, the frame is more prone to twisting, which affects the torsional spring constant and makes it more likely to collapse into the catheter.

[0019] In various situations, it has been recognized / discovered that by implementing an asymmetric property that enables the perimeter of the frame to conform to the lateral angle of the aortic arch and accommodate the lateral displacement of the ostium of the brachiocephalic (innominate) artery, a high degree of desirable conformity and a related filter seal can be achieved. This can be facilitated by implementing the natural angular and shape features of the aortic arch and the natural displacement of the vascular branch ostia. When viewed from above, the frame may be configured to bend from front to back and from right to left to correspond to the bend of the aorta. The BCA ostium is displaced posteriorly from the centerline of the aorta. During implementation, the bend due to the asymmetry follows the lateral angle of the aortic arch, and a wider portion of the perimeter of the frame extends laterally to cover the displacement of the BCA ostium.

[0020] In various embodiments, the frame may have a progressive or changing bending stiffness. In certain embodiments, these techniques may comprise an asymmetric configuration for desirable compliance as described herein. For example, for the various frames illustrated in the drawings and / or described herein, the changing bending stiffness may be implemented in any shape or size by changing the composition, geometric shape, thickness, adding or removing struts, or other techniques. Thus, it has been further recognized / discovered that by implementing such a changing bending stiffness, the compliance of the frame is improved, as described herein. This technique may be used with or separately from the above-described configurations regarding asymmetry.

[0021] In some embodiments, the perimeter of successive frames exhibits progressive bending stiffness (rigidity) along the longitudinal axes in the Z and X directions, where the X direction is substantially perpendicular to the deployment direction (e.g., of the catheter or extension arm used for frame deployment) in a plan view, and the Z direction is directly upward or downward with respect to the transverse plane of the frame. In certain embodiments, the proximal end of the frame transmits a certain amount of lift force in the Z direction over a certain length of the frame, the central region transmits less lift force, and the distal region transmits even less lift force over the remaining length of the frame. In the X direction, the varying / progressive bending stiffness (rigidity) can facilitate the transmission of a portion of the expansion force in the central region of the frame, which can promote the full expansion of the frame from the hinge-type connection at the proximal end and the full expansion of the distal region to the distal end of the expansion. The distal region exhibits more expansion force, enabling the frame to expand to the width of the aorta. Thereby, the frame can adapt to various diameters of the aorta. Accordingly, the progressive bending stiffness (rigidity) in the X direction can facilitate the frame's expansion into the shape of the aorta while ensuring flexibility to follow the irregularities of the shape. In certain embodiments, the progressive bending stiffness (rigidity) achieves compliance and expansion by providing the mechanical properties of the material used for the frame, such as the superelastic properties of Nitinol, and / or by using various configurations such as supporting inner rails, varying geometric shapes, and / or tapering frame rail widths.

[0022] The various embodiments described herein and in the drawings show some specific dimensions, materials, and other characteristics. Such characteristics are examples of specific applications and can be other representative examples with various aspects considered to be implemented accordingly. Further, the various features of asymmetry and varying bending stiffness described above or herein can be utilized alone or in combination with the embodiments illustrated in the drawings. For example, some embodiments are directed to frames with specific asymmetric configurations. Another embodiment is directed to frames with varying bending stiffness. Still another embodiment is directed to frames with both asymmetry and varying bending stiffness.

[0023] Another embodiment is directed to an apparatus comprising an extension arm, a frame connected to the extension arm, and a filter having an opposite face region that terminates at the periphery of the filter. The filter, the frame, and the extension arm are configured to conform one of the opposite face regions to the inner wall of the tubular structure. For example, to ensure such conformity, one or both of the asymmetry and varying bending stiffness along the sides of the frame may be utilized. In some embodiments, the extension arm may engage each surface of the inner wall of the tubular structure to facilitate pressurization.

[0024] Regarding embodiments including asymmetric frame characteristics, such characteristics can be implemented in various ways. In some embodiments, the frame has an asymmetry that mimics the asymmetry inside the inner wall. For example, when implemented in the aortic arch, the asymmetry may follow the relevant asymmetry within the aortic arch. Thus, the frame may be manufactured in such a way that such a conformable geometric shape is set.

[0025] In some embodiments, the frame is asymmetric in the transverse and longitudinal directions with respect to the longitudinal direction corresponding to the extension arm and the transverse direction that is perpendicular to the longitudinal direction and extends across the filter. The frame has a wide distal end and a narrow proximal end, is asymmetric in the transverse direction, the proximal end is coupled to the extension arm, and the distal end extends away from the extension arm. The frame has a longitudinal asymmetry including an inner bend in the central region on the rear side of the frame and an outer bend on the front side of the frame. In a particular embodiment, the frame has a longitudinal asymmetry such that the distance between the rear frame rail and the center line at the proximal end is smaller than the distance between the front frame rail and the center line at the proximal end. In another embodiment, the frame includes an inner bend in the central region on the rear side of the frame and an outer bend on the front side of the frame, and has a longitudinal asymmetry such that the distance between the rear frame rail and the center line at the proximal end is smaller than the distance between the front frame rail and the center line at the proximal end.

[0026] In certain embodiments, the frame is asymmetric in both the transverse and longitudinal directions. The transverse asymmetry comprises a wide distal end and a narrow proximal end, the proximal end being coupled to the telescopic arm and the distal end extending away from the extension arm. The longitudinal asymmetry includes one or more of an inward bend in a central region on the posterior side of the frame, an outward bend on the anterior side of the frame, and a smaller distance between the posterior frame rail and the centerline at the proximal end than the distance between the anterior frame rail and the centerline at the proximal end.

[0027] In certain embodiments, the frame has an asymmetry that facilitates peripheral distortion to accommodate the asymmetry inside the inner wall. For example, the frame may engage the inner wall by adapting the periphery of the frame to the transverse angle of the aortic arch and the transverse displacement of the ostium of the brachiocephalic artery.

[0028] The frame may have a transverse displacement relative to the conforming structure. For example, the frame may have a proximal end coupled to the extension arm and extend to a distal end where the frame terminates. The distal end may be laterally displaced relative to the proximal end and also relative to the direction in which the extension arm extends.

[0029] The frame may conform to various structures. For example, the frame may be configured to facilitate peripheral distortion to accommodate the asymmetry inside the inner wall of the human aortic arch. The frame has an asymmetry with a laterally narrow feature relative to a laterally wide feature on the opposite side.

[0030] The seal to the sidewall of the filter can be affected in various ways. In some embodiments, the extension arm may be configured and arranged with the frame to apply a force to the frame that seals the periphery of the filter and the frame against the inner wall. In certain embodiments, the extension arm and the frame operate together to seal the filter around the opening of the inner wall and filter the fluid flowing through the opening.

[0031] The frame may be formed and implemented with various structures. In some embodiments, the frame comprises an inner peripheral member and an outer peripheral member separated by a gap, and the outer peripheral member extends around the inner peripheral member. The gap may be a small one such as a crack where the inner peripheral member and the outer peripheral member (e.g., rails) contact or substantially contact. In certain embodiments, struts connect the inner peripheral member and the outer peripheral member. The extension arms are configured and arranged with the inner peripheral member and the outer peripheral member such that the inner peripheral member and the outer peripheral member press respective portions of the filter against the inner wall to seal the filter to the inner wall of the tubular structure.

[0032] In a more detailed embodiment, a portion of the frame is separated by a gap and comprises an inner peripheral member and an outer peripheral member that form a first portion of the perimeter of the frame, and a second portion of the perimeter of the frame is a single member connected to both the inner peripheral member and the outer peripheral member.

[0033] In various embodiments, the frame has different rigidity characteristics in different portions. For example, the frame has different widths in different portions, and the thick portions of the frame are more rigid than the thin portions of the frame. The frame has opposing planes and has a constant thickness between the changing widths of the planes. The frame has different geometric shapes in different portions, and the different geometric shapes result in different rigidity characteristics. In a particular example, the frame has a proximal end and a distal end, and a first opposing rail and a second opposing rail are coupled to the proximal end and the distal end respectively, with a filter extending therebetween. The lateral flexibility of the first opposing rail is different from the lateral flexibility of the second opposing rail.

[0034] In various embodiments that may be utilized in the aortic arch, the filter is configured and arranged with the frame and the extension arms to expand to a deployed state with the frame to conform to one of the opposing surfaces and to collapse to a collapsed state to retract into the catheter. In such embodiments, the frame comprises opposing rails extending from the proximal end to the distal end, and each opposing rail has a substantially the same length and a different shape from each other.

[0035] Various embodiments are directed to methods of manufacturing the devices described herein. In some embodiments, the method comprises providing a frame member, attaching the frame member to a fixture that mimics the features of the inner wall of the tubular structure, and configuring the frame member in a shape that is defined by the fixture and mimics the features of the inner wall of the tubular structure. Providing the frame member comprises cutting a planar frame from a sheet.

[0036] Various embodiments are directed to methods of filtering particles flowing through the side walls of the upper aortic arch. Such embodiments may comprise adapting the frame and filter to the side walls of the upper aortic arch and the openings of the blood vessels by utilizing one or more of asymmetry, lateral flexibility, and frame rigidity, adapting the perimeter of the frame to the perimeter of the opening, and adapting to the angle of the aorta and the natural displacement of the opening of the blood vessels.

[0037] Certain other embodiments comprise a frame and a filter, and further comprise a catheter configured with the frame and filter such that the frame and filter extend into the tubular structure to facilitate adaptation of the frame and filter to the inner wall of the tubular structure. Such adaptation facilitates filtering of the fluid flowing through the side walls to capture particles within the filter. The catheter, frame, and filter are further configured such that the filter and frame with particles captured therein can be retracted within the catheter.

[0038] According to certain embodiments, the device comprises an extension arm, a frame connected to the extension arm, and a filter (e.g., a mesh or other material) having an opposing surface region and terminating at the periphery of the filter. The filter is connected to the frame at its periphery and expands with the frame in the deployed state, and in the deployed state, engages each surface of the inner wall of the tubular organ with the extension arm, and by applying a force to seal the periphery of the filter and the frame against the inner wall, it is configured and arranged with the frame and the extension arm to conform one of the opposing surface regions to the inner wall of the tubular organ. The shaft is connected to the extension arm and is operable to slide within the catheter and apply a force to the frame to position the extension arm, the frame, and the filter against the inner wall of the tubular structure. Further, the shaft may be operable to crush the frame and the filter into a collapsed state and retract them into the catheter. Thereby, it is possible to facilitate the capture and removal of particles such as those that have migrated during a surgical procedure. For example, with the filter sealed to the opening in the side wall of the aortic arch, a portion of the filter facing the inner region of the aortic arch can capture particles from the blood flowing through the filter and into the artery through the side wall, and then these particles can be removed.

[0039] As described above, various filters can be used. Various embodiments comprise a filter having opposing surfaces, with a peripheral end surrounding the outer periphery of the filter. For example, a sheet of mesh or other material may be used for the filter. Such a material has a lower surface and an upper surface that meet along the peripheral edge of the filter when placed in a plane. This peripheral edge may be coupled to the frame and used for sealing against the inner wall of the blood vessel.

[0040] The frame may be implemented in various ways. In some embodiments, the frame comprises an inner frame configured and arranged to seal a filter to an inner wall, an outer frame, and a plurality of struts connecting the inner frame and the outer frame. The struts transmit a force applied to the outer frame via an extension arm to the inner frame, where they operate to apply the inner frame flexibly against the inner wall. The struts are operable to make the inner frame more prone to distortion relative to the outer frame by applying a spring force and facilitating the adaptation of the outer frame to the inner wall.

[0041] The filter may be coupled in various ways. In some embodiments, the filter extends between the inner frame and the outer frame around the periphery of the inner frame. The struts apply a force between the inner frame and the outer frame and seal an opening in the inner vascular wall by pressing the inner frame and the outer frame against the inner vascular wall and around the opening in the inner vascular wall. As described herein, the struts facilitate sealing under changes in pressure conditions that may result from blood flow and movement of the vessel wall. For example, the inner frame and the outer frame may maintain displacement positions relative to each other that change in response to the applied force.

[0042] The various embodiments described above and herein may comprise some or all of the various elements described. For example, some embodiments comprise a frame operable in accordance with a frame described herein. Another embodiment comprises a frame and a filter coupled to the frame, or a frame and an extension arm coupled to the frame, or a frame, a filter, and an extension arm. Yet another embodiment, as described above, is operable to move within a catheter and comprises a shaft coupled to the frame. Yet another embodiment comprises a catheter extending from a proximal end to a distal end and operable to receive a shaft, a frame, and any other member. Various functions related to the deployment of the frame, the sealing of the frame to the inner wall, and the retraction of the frame into the catheter can be integrated into various members. For example, in an extension arm having at least two bends in a portion of the extension arm connecting the shaft and the frame, the bends may be used for engagement with the inner wall and for applying pressure to the frame and the accompanying filter. Accordingly, for the side wall, the spring-like characteristics of the extension arm that facilitate sealing of the opening in the side wall are utilized.

[0043] The various aspects are directed to an apparatus for use with a catheter and comprise a filter having a frame and a multi-jointed arm connected to the frame. The frame forms a perimeter of the filter and separates opposite faces of the filter. The multi-jointed arm, when deployed within a tubular organ, engages an inner wall portion of an opposing tubular organ and utilizes the inner wall to seal the filter against the inner wall by applying a force to the frame.

[0044] Various embodiments are directed to controlling a catheter component, as well as a vector filter and isolation region, to facilitate insertion into its delivery catheter lumen, reducing potential damage to the catheter component including outflow of the filter / frame, maintaining a air-free state, and packing an automated vector device in a regulated state for transfer into the delivery catheter. The technique may include a protective member that houses a catheter component including a filter and a frame. The filling portion operates with the protective member to regulate the catheter component in a state where it can be controlled to move into the delivery catheter lumen and provide an air-free state with a visual indicator indicating the presence of air trapped within the component. This can provide protection from rough handling during sterilization, transportation, and assembly during handling. The handle portion facilitates insertion of the catheter component from the filling portion into the delivery catheter lumen. The handle portion further operates to lock and unlock the shaft of the catheter component, move along the shaft, and transmit torque and push-pull forces from the operator through the handle to the shaft, and thus to the filter / frame when locked. The technique is implementable with the handle portion as illustrated (e.g., shown in FIG. 16).

[0045] Some embodiments include the application of methods that include various components described herein, and may include manufacturing methods and / or methods of use. According to one or more embodiments, a method of manufacturing an apparatus may be implemented as follows. Provide an extension arm, a frame connected to the extension arm, and a filter. The filter includes a filter (e.g., mesh or other material) that terminates at the periphery of the filter and is connected to the frame at its periphery. The filter operates with the frame and the extension arm such that in the deployed state, it expands with the frame. In the deployed state, the extension arm engages each surface of the inner wall of the tubular organ, and by applying a force to seal the periphery of the filter and the frame against the inner wall by this engagement, one of the opposing surface regions conforms to the inner wall of the tubular organ. In some embodiments, the mechanical properties of the frame are optimized by performing a thermo-mechanical treatment on the frame to set a rigidity that facilitates the deployment of the frame and the filter into the tubular organ and the sealing of the frame and the filter against the inner wall of the tubular organ. The thermo-mechanical treatment of the frame may include setting the rigidity by one or more combinations of cold working of the frame (e.g., nitinol), adoption of a shape that sets the heat treatment temperature, and selection of the chemical composition of the alloy forming the frame.

[0046] One or more embodiments in the usage scenario include filtering blood or other fluids using the filter and the frame described herein as follows. It expands with the frame in the deployed state, and in the deployed state, the extension arm engages each surface of the inner wall of the tubular organ, whereby one of the opposing surface regions conforms to each surface of the inner wall of the tubular organ. By this engagement, a force is applied to the frame, and the periphery of the filter and the frame are sealed against the inner wall. This operational feature may be implemented according to one or more embodiments herein, such as by utilizing an extension arm that engages the side wall.

[0047] Various embodiments are directed to an embolic protection device designed to protect the brain from strokes and embolic debris during left atrial procedures such as TAVR. The dynamic two - end sealing of the device is achieved by controlling the system stiffness and natural frequency during the cardiac output (CO) cycle. For implementation in a hemodynamic environment, the natural frequency can be set high compared to the frequency of the cardiac cycle. Such a high natural frequency makes it easier to lower the displacement of the frame, thereby improving the seal. The device comprises a natural frequency (N) that is a function of the maximum displacement (Ds) (at the distal end) relative to a reference point (La), joints of the extension arms, and a frame having their characteristics. In various embodiments, the stiffness spring characteristics and other aspects of the frame are operable to flex during the CO cycle, whereby the frame and the attached filter are maintained at a location to seal the opening in the sidewall of the aortic arch. Various different filters can be attached to the frame and used to filter substances passing through the opening in the sidewall of the aortic arch. In some embodiments, struts are used between each frame component member along with the stiffness of the frame that seals the filter against the sidewall, moving flexibly with the aortic arch and maintaining the seal under changing pressure conditions. The extension arms articulate to interact with the inner wall of the aortic arch, apply pressure to the frame, and can maintain their location flexibly.

[0048] Referring to the drawings, various embodiments in FIGS. A - F may be implemented by aspects shown and / or described in conjunction with FIGS. 1 - 35, including aspects related to utilizing single or double frames, many or few struts, that affect the followability of the frame and associated mesh due to the physical characteristics of the tubular structure.

[0049] Referring to FIG. 36, the apparatus 100 comprises an asymmetric frame that may be implemented with the filters of this specification according to various embodiments. The drawings shown may be a plan view such as a top view when inserted into the bow of a tubular structure. The frame comprises rails 110 and 113 that extend from a proximal end 120 to a distal end 130. Rail 110 has an asymmetry with respect to rail 113, generally forming a small region at 111 and a large region at 112. Only a part is shown for clarity, but a filter member 140 may be coupled to the asymmetric frame.

[0050] In some embodiments, rails 110 and 113 may have different flexibility characteristics, such as by thickness, material, geometric shape, or a combination thereof. For example, rail 110 may be made more bendable than rail 113 to conform to a particular configuration of a tubular structure such as the aortic arch. In this state, rail 110 may be thinner than rail 113 and / or have a different geometry or material composition to facilitate a different flexibility.

[0051] In an exemplary embodiment, the proximal end 120 is coupled to or is part of an extension arm that facilitates deployment of the asymmetric frame and retraction into the catheter. Further, the proximal end 120 may have features such as a necking as shown to be more easily bendable laterally. Other features as shown in FIG. 40 may also be used.

[0052] FIG. 37 shows an apparatus 200 comprising an asymmetric frame 210 with struts 211 and 212 that provide rigidity and may be implemented with the filters of this specification according to another embodiment. Struts 211 and 212 provide rigidity to a portion near the proximal end 220 of the asymmetric frame 210, and the distal end 230 of the frame is without struts and is more flexible. Further, various regions of the asymmetric frame may have structures that exhibit different rigidity characteristics as shown in FIG. 36.

[0053] FIG. 38 shows an apparatus 300 comprising an asymmetric frame 310 with struts 311 and 312 that provide rigidity and may be implemented with a filter of this specification according to another embodiment. Struts 311 and 312 extend further from the frame than struts 211 and 212 shown in FIG. 37, thereby providing different rigidity characteristics and improving the overall rigidity near the proximal end of frame 320 compared to distal end 33.

[0054] FIG. 39 shows an apparatus 400 comprising an asymmetric frame 410 with an offset distal end 430 and struts 411 and 412 near a proximal end 420 that provide rigidity and may be implemented with a filter of this specification according to another embodiment. The offset shown as distance “D” may be adjusted for a particular application. For example, when used in the aortic arch, the offset may be adjusted such that the asymmetric frame 410 is more likely to conform to the inner wall of the aortic arch.

[0055] FIG. 40 shows an apparatus 500 and various structures that may be implemented with a filter of this specification according to another embodiment and are laterally flexible. Specifically, in the above or another drawing, features 510, 520, and 530 may be implemented at the proximal end of frame 505 or the frame shown in FIG. 39. Thereby, for example, when deploying the frame from a catheter into a separation region belonging to the aortic arch to filter blood flowing through an opening in the inner wall of the aortic arch, lateral movement of the frame is facilitated. With these features, the frame can adjust (e.g., torsionally twist) and / or control the natural frequency of the entire frame with respect to the filling and emptying of the cardiac cycle.

[0056] FIG. 41 shows an apparatus 600 comprising a flexible frame that may be implemented with a filter of this specification according to another embodiment. As shown at the bottom of FIG. 41, the frame may bend such that frame rails comprising a frame rail region 610 extend, and an opposing frame rail comprising a flexible frame rail region 611 may contract. Thereby, adaptation to various features of the inner wall of a tubular structure is facilitated.

[0057] FIG. 42 shows an apparatus 4200 with a flexible frame that may be implemented with the filter of this specification according to another embodiment. The frame is shown at part A, the extension arm at B, and the shaft at C. The apparatus 4200 may be implemented according to an embodiment of this specification to conform the frame to, for example, the inner wall of a tubular structure.

[0058] FIG. 43 shows an apparatus 4300 comprising a flexible frame 4310 and a filter 4320 that may be implemented according to another embodiment. As shown, the frame 4310 is coupled to an extension arm 4330 and a shaft 4340. The apparatus 4300 may be implemented according to an embodiment of this specification to conform the frame 4310 to the inner wall to seal the filter 4320 against, for example, an opening in the inner wall of a tubular structure.

[0059] Referring to FIG. 10, an assembly / system of a frame / filter and an extension arm (EA) is shown. Reference points A, B, and C support the EA and generate a force (F) and a torque (T). The system comprises a frame assembly wound around its periphery with a thin filter, and a support extension arm at the proximal end. Thereby, a mechanical force is generated that can overcome the hemodynamic forces affecting the frame / filter assembly. The support EA connects the proximal end of the frame assembly. The main functions of the extension arm and the shaft are: a) to transmit the pushing force and torque for pushing, pulling, and rotating the frame assembly through the catheter; b) to deploy and position the frame / mesh assembly at the intended position for the seal and the filter; c) to provide the necessary sealing force against the aortic arch (AA) wall; d) to provide sufficient rigidity to the frame / filter assembly during the cardiac output cycle and the arterial pulse; e) to provide various reference points along the descending aorta to support and reduce the displacement of the frame / filter. FIG. 10 shows the frame / filter assembly and its multi-jointed extension deployed in the AA and the descending aorta. Reference points A, B, and C support the frame assembly and generate the necessary sealing force (F) and the holding torque (T) during deployment. Various possible combinations can be implemented in type I, type II, or type III arcuate geometries.

[0060] The joints can be implemented in various ways to suit specific embodiments. In some examples, the EA is fixed at various points (A, B, C, etc.) on the descending aorta and provides physical support and mechanical spring force to the seal surface of the frame. The EA comprises segments of a specific width, short, and angled, connected to form a continuous entity as shown in FIG. 11. Each segment articulates and rotates with respect to each other and each contributes to the overall rigidity of the EA.

[0061] The total spring force (F) and torque (T) of the EA are the sum of the individual forces and torques of each multi-articular segment. The joints of each segment are characterized by the segment length (L), segment stiffness (K), and segment geometry (width and thickness). The multi-articular segments of the EA, along with the bent and twisted segments of the EA, enable the transition section between the shaft and the proximal end of the frame assembly to move more precisely in accordance with the curved structure of the descending aorta. The total stiffness (K), end displacement (D), seal force (F), torque (T), and final natural frequency (N) of the frame / filter are controlled by the multi-articular characteristics of the EA.

[0062] Referring again to FIG. 11, the multi-articular segments of the extension arm provide the seal F and T necessary to minimize D. The design parameters of the extension arm that control its characteristics are: 1) segment lengths (L1, L2, L3, etc.); 2) relative rotation angles (Φ1, Φ2, etc.); 3) segment relative stiffness (K); 4) the rotational tendency of each segment clockwise / counterclockwise (CW / CCW) with respect to the shaft. Further, the physical properties of the arm material, linearity, and corrosion can affect the application. The optimal design may be implemented to ensure that the EA (given the correct combination and sequence of LAs) always has a net positive F and T available to seal the frame / filter against the AA wall.

[0063] The modes of stiffness and natural frequency may be implemented to affect the seal as described above. The main function includes generating a dynamic two-end seal against the AA wall and filtering embolic fragments from the circulation of the three arcuate blood vessels. To achieve this purpose, the K (the ratio of F to D) of the multi-articular EA must overcome the net force resulting from the cardiac output (CO) and the impulsive flow / pressure profile during each cycle. The frame / filter assembly should have a D of 0 without vibration or separation from the AA when an external force is applied. S to the ratio of F) must overcome the net force resulting from the cardiac output (CO) and the impulsive flow / pressure profile during each cycle. The frame / filter assembly should have a D of 0 without vibration or separation from the AA when an external force is applied. SIt is desirable to behave so as to approach. The total stiffness (K) of the EA can be set to control how much the frame / filter assembly is displaced from its sealing position. A high N of the frame / filter assembly indicates a high K of the corresponding EA (with respect to LA), and thus, D S is zero or minimum. A lower total stiffness coefficient of the EA with respect to LA indicates a lower frequency, and thus, D S becomes high.

[0064] Any separation between the frame / filter assembly and the AA wall is a potential for leakage. The N of the frame in the CO environment indicates how much the K of the EA supports the frame / filter. The stiffness and damping characteristics of the EA determine how smoothly the frame structure returns to its stable sealing position after being exposed to sudden CO forces or arterial pulse patterns (1). For example, the fundamental natural frequency of any structure can be approximated roughly as follows:

Equation

[0065] In an AA environment, the stability of the frame / filter structure, and thus the sealing efficiency, is a linear function of its stiffness and natural frequency. The articulated extension arm described herein enables the frame to be stably fixed on its own over the descending aorta, pass through complex geometries, and generate sufficient sealing force and torque to overcome the natural hemodynamic forces of human cardiac output.

[0066] The natural frequency (N), stiffness (K), and time constant (Tau) of the frame assembly in the examples herein are used to facilitate application to the aortic arch environment of the human body. In various embodiments, embolic devices that utilize these aspects are implemented to protect the brain from stroke during left atrial procedures of interest in TAVR. The functional requirements of the dynamic two-end seal of the device require control of the system time constant as a response to cardiac output. The response of the frame is directly related to the natural frequency of the structure, and its stiffness. The system comprises a frame assembly with a thin-film filter mesh wound around its periphery, and a support extension at the proximal end, and generates mechanical forces. In its inflated (or deployed) state, it covers the three main human arteries of the aortic arch and deflects incoming emboli. In its collapsed (or packaged) state, it fits completely inside the catheter prior to deployment. When deployed within the AA, the frame and mesh assembly are subjected to multiple vector forces. These include a) hemodynamic forces due to cardiac output (CO), b) dynamic and structural forces of the vibrating AA wall, c) buoyancy of the thin mesh, and d) mechanical spring forces of the frame assembly and its extensions that generate sealing force against the wall. FIG. 13 shows an example of the device in free space experiencing the main mechanical and hemodynamic vector forces.

[0067] Functional aspects include, for example: 1. generating a dynamic two - end seal against the aortic arch wall; 2. diverting embolic fragments from the arcuate vascular circulation through a filter or away; 3. resisting hemodynamic forces of flow, pressure, mesh flotation, and tension on the filter mesh film; 4. adapting to changes in the anatomical curvature of a typical aortic arch; 5. minimizing unfiltered blood flow around the device; 6. providing an appropriate area and filter coverage rate for large arcuate vessels; 7. providing appropriate spring force and stiffness to reduce the system response time during each CO cycle impulse; and 8. preventing system in - phase vibration with CO having a reduced magnification.

[0068] The net balance of forces imparted to FNET (e.g., the frame assembly and filter mesh) during each cardiac cycle results in the attachment and sealing of the system to the upper surface of the AA, where the three major arteries originate. The aortic wall expands and contracts radially during each cycle. Thus, this vibration expands or contracts the diameter of the arch. The frame dynamically conforms to the cardiac cycle so that the seal of the frame ends against the wall is fully maintained, preventing leakage.

[0069] In addition to the dynamic end seal, as described above, an appropriate coverage rate around the combined arcuate arteries is ensured such that small displacements of the frame / mesh assembly due to changes in FNET at each cardiac cycle output (CO) do not cause blood leakage through the seal interface. The net system vector force (mechanical and non - mechanical), FNET, is configured to push against the frame / AA seal interface, thereby enabling the filter mesh to perform its function without fluid loss due to leakage.

[0070] The pressure-time profile in the aorta is not a continuous smooth curve, and various embodiments solve this problem while maintaining a seal against the sidewalls of blood vessels such as the aortic arch. Each CO cycle (AP line) generates three individual pressure profiles within the aorta, resulting in a function that applies a stepwise pressure or force to the frame / mesh assembly. The change in pressure in each region (DP) results in a blood flow rate (Q) and a flow velocity (V) in the aorta. The flow rate (liters / minute) can be approximated as Q = VA, where A represents the cross-sectional area of the aorta at the point of interest.

[0071] Figure 14 shows an exemplary aortic pressure (AP) curve, and the regions "2-3", "3-5", and "5-6" are distinguishable as having individual profiles, which are what various embodiments seek to address. Within the aorta, the pressure step function is: a) the aortic valve snaps open and pressure from the LV is pumped into the aorta (about 0.15 seconds, 100 Mm-HG, region "2-4"); b) the aortic valve snaps closed and the pressure within the aorta rises slightly above the pressure value in the LV due to the elastic energy of the inflated wall (the dicrotic notch is about 0.1 seconds, region "4-5"); and c) occurs under conditions of isovolumic dilation where the pressure gradually decreases (about 0.2 seconds, 90 Mm-HG seconds, region "5-6"). The dicrotic notch indicates a gentle disruption of flow due to a short reverse flow of blood closing the aortic semilunar valve as the ventricle relaxes. Each region generates a forcing function on the frame assembly. The absolute value of each forcing function is (|FCO|). When |FCO| interacts with the frame / mesh assembly, the net result is |FCO| < FNET without being amplified around its natural frequency. Each stepwise force input can be mathematically described as

Equation

[0072] In various embodiments, the behavior of the frame / mesh assembly due to the influence of FNET, which is a combined force, can be represented as a second-order system. For the response of the system, the system can be shown by exciting a series of stepwise pressure (or force) functions in each region. The stepwise input is characterized by a fast initial rise time (T) and a flat steady state (F0 = 0, F1 = |FCO|). The behavior of the second-order system can be modeled as a combination of acceleration, mass, damping coefficient, and stiffness parameters. The system responds to the force of the fast rise input by converging to either a time constant (Tau) and reduced amplification, or no vibration with high / low amplitude. In the aorta, the behavior (response) of the frame / mesh assembly can be modeled using mass (m), damping factor (c), and stiffness coefficient (K) as shown in FIG. 15. If the zero value of "Y0" corresponds to the position of the frame (spring) not mounted (immediately after release from the catheter), the force Fs required to move the frame / mesh assembly by a distance y is given by Fs = kY, where k is the spring constant or stiffness of the system. The parameter "Y" corresponds to the displacement of the distal end of the frame assembly. Equation (2) defines the frequency response of the system to a stepwise force input (|FCO|), where "wn" is the undamped (natural) natural frequency of the system and "ζ" is the damping coefficient, related to the damping factor (c). In one or more embodiments, a stable state is obtained within the shortest possible time without direct or periodic displacement (change in Y). A "highly damped" system (ζ = 1) represents the fastest path to the stable point (minimum frame displacement, no periodic operation, shortest time). However, these elements can be enhanced as other design elements are considered before selecting the appropriate damping coefficient, natural frequency, and tuned stiffness parameters for system stability.

[0073] It is desirable for the system to behave such that it reaches the fastest and vibration-free 0 displacement (Dy = 0) when subjected to a stepwise pressure input. This state is referred to as "highly damped",

Number

Number

Number

Number

[0074] The main stiffness (K) of the frame / mesh assembly may be implemented by incorporating continuous short bends (joints) of the extension arm. Thus, a force-based system that depends on mechanical spring forces rather than hemodynamic forces (such as differences in fluid pressure across the mesh) can be used to generate the sealing force against the aortic wall. The joints have acute angles with respect to each other and with respect to the frame. This allows for better maneuverability of the frame and, at the same time, controls the stiffness of the system in the desired direction. The values of directionality and stiffness may be implemented by balancing functional and mechanical requirements. The system stiffness (k) is applied with appropriate strength and direction so that the frame / mesh assembly, when present inside the catheter (e.g., packaged into AA and pre-positioned), facilitates adaptation to catheter guidance and dimensional regulation. The length and angle of the joints are adjusted to provide a desired amount of friction within the catheter and to facilitate adaptation to AA and the small diameter of its curved path when guided within the catheter. A constant sealing force against the periodically expanding aortic wall is thus maintained. The natural frequency is not amplified and is set to adapt to the wall that changes dynamically when its stiffness responds to a stepwise force function. Further, the time until reaching the stable point is adjusted so as not to overlap with the start of the next force function. The time until reaching stability is set to be less than the minimum time step of the force function (t).

[0075] The rigidity can be set to adapt to specific embodiments. The functionality can be set according to how the upper (frame) and lower (extension) function and complement each other during surgery. The frame and extension of the assembly both have directional rigidity and articulation points in different planes. The frame part is provided with a plurality of rails and braces on both sides of its center line, forming a larger surface area compared to a single round wire. The braces connect the rails to each other and form a dynamic spring coefficient that is always in contact with the wall of the aorta to expand and contract with the cardiac cycle. At the same time, this combination of "continuous" and "parallel" springs (braces) embedded in the frame assembly can adapt to many degrees of freedom over a three-dimensional space. Similarly, the extension of the assembly has its own functionality. Its function is to guide within the lower part of the arch and support the upper part (frame). This includes various continuous bending with different diameters of various geometric shapes and material properties (and thus rigidity) along it. By controlling the rigidity of the extension along its curved path, its spatial position (i.e., targeting a reference point relative to the side wall), and the torsional behavior of the natural frequency of the frame, it can itself stay within the desired design range. The range of the natural frequency of the frame can be within 2 - 15 Hz, but a narrower band can be achieved by controlling the rigidity in different parts of the frame and extension. The frame and extension can function as an integrated system, but there may be a certain operational independence (separation) between them to avoid crosstalk. The natural frequency and rigidity of the frame are set so that the frame and seal are not (greatly) affected by the interference received by the extension caused by the cardiac output or user input after the frame is placed in the desired position. The function of the joint shown in FIG. 13 etc. can be set to be "loosely" related to the overall rigidity of the frame and extension, and at the same time, to allow a smooth transition between the two so that the relatedness is strongly maintained (e.g., like a universal joint of an automobile axle).

[0076] In general, controlling the stiffness of any part of an extension or a frame can be set according to one or more of the following elements: a) material properties and chemical / physical composition; b) geometric stiffness which is a function of form and dimensions; c) shaping parameters and processes capable of generating the desired material stiffness. By the combination and selection of each category, continuous multi-joint characteristics of both the frame and the extension in each part can be obtained.

[0077] In some embodiments, the desired design can be achieved by setting features such that the system slowly and monotonically approaches its final state value (y = KF1) without vibrating while satisfying functional conditions at the same time. The speed at which y approaches its final value depends on the value of ζ. The higher ζ is, the slower the value of y changes without vibration. The damping coefficient is set according to the damping factor (c), the mass of the frame / filter mesh, and the stiffness coefficient. However, the damping factor (c) can be implemented as a variable factor which is the value of the factor of mesh density, porosity, and buoyancy in the hemodynamic environment. Also, the buoyancy force (in this case) is also a function of the amount of blood displaced in the aorta and the surface area of the filter mesh. The hemodynamic drag force affecting the filter mesh is a function of the viscosity of the blood, the mesh surface area, and the drag coefficient. The smaller the surface area of the mesh, the smaller the drag force between each stepwise force function, and the smaller the friction refined inside the catheter. A filter mesh having a density higher than that of blood generates a force against the spring force of the frame. A lightweight mesh can be implemented to reinforce the sealing force against the wall. Equation (3) represents an "over-damped" system where ζ > 1. The system does not vibrate when it is subject to a stepwise input. F1 = |FCO| is the initial force by the stepwise force function when the aortic valve opens.

Number

[0078] A high value of ωn causes the system to reach its final stopping point more quickly, and the coefficient “Tau = ζωn” is the time constant of the system. One time constant (1×Tau) is defined as the time required for the value of the system's displacement to reach 62.8% of its final value. Therefore, by controlling and carefully selecting the values of K, ζ, and ωn, the system can be optimized even considering the effects of frictional and buoyant forces.

[0079] The total time span from region 2 to region 6 of the AP profile shown in FIG. 14 is approximately 0.50 seconds. Thus, the time contributions from each region of AA in each CO cycle are approximately 0.15, 0.10, and 0.25 seconds. The total system time constant (Tau) is always shorter than the shortest rise time of the force function in the aorta (in this example, <0.10 seconds). Also, an additional safety margin can be set to fully stabilize the system before the next force function starts. This can avoid vibrations, for example, when FNET is on the order of the same magnitude as FCO. (|FCO| = FNET).

[0080] Various aspects of the frame and / or extension arm may be further adjusted to suit specific needs such as, for example, mounting the structure within a catheter, reducing friction within a tube, expanding a mesh for a greater coverage rate, overcoming catheter bending and kinking, resisting push-pull forces of a delivery shaft, resolving the floating force of the mesh when deployed, and resolving the dragging force of the mesh when moving within the catheter. The frame may be extensible such that its shape and properties are maintained from one dimension to another (i.e., the shape is maintained in a similar manner, such as from 8F to 10F in different embodiments). The shape can start from a planar (e.g., nitinol) material or a hypo tube and can then be achieved by performing laser cutting or other cutting methods. The shape of the frame assembly can further include additional features such as additional backbones in the middle or sides of the frame assembly. Also, the FA shape can have various dimensions and angles in both the axial and transverse directions to adapt to various aortic arch biological tissues and dimensions. The frame may be implemented to provide / address one or more of torsional forces (e.g., resistance to torsion of AA), vertical forces (pressing against the coverage rate of three arteries to form a seal), lateral forces (e.g., perpendicular to the plane of AA), transverse hemodynamic / fluid forces in the cross-axial direction, and axial lateral forces with respect to the plane of AA, and resistance to fluid forces due to axial cardiac output / hemodynamic forces.

[0081] Regarding the filters described herein, various manufacturing techniques and processes may be employed to obtain the desired results. In some embodiments, an austenite final transition temperature above room temperature that achieves AF = 32°C is used. Various nitinol shaft properties can be obtained by controlling the cold working and heat processes of nitinol wire / rod to obtain a specific austenite final temperature and thus the desired stiffness and pushability of the shaft.

[0082] The shaft whose features are described in this specification can be designed with features related to flexibility to meet specific requirements. For example, the shaft can pass through a tight diameter, resist pushing / pulling forces / shearing forces inside the tube, provide a 1-to-1 torque transmission, provide a desired rigidity (K value) with respect to the combined rigidity of the frame and the isolation area, provide reduced superelasticity to obtain an optimal rigidity for feeding the frame well through tortuous biological tissues, generate a major vertical force with respect to the coated area, provide a reference point for mesh connection, and be formed to provide a torsional force to the frame.

[0083] In a specific manufacturing method, a flat superelastic nitinol sheet having a target final frame thickness, for example, 0.008 - 0.020 inches, is used. Next, the thickness of the nitinol sheet is selectively reduced to about 0.001 inches in order to obtain a mesh surface coverage rate before generating the final mesh pattern by laser cutting, an electric etching process, or other similar techniques. Finally, the final mesh pattern is generated by either laser cutting or an electrochemical process. This provides one nitinol frame assembly prior to the final shape setting. The final shape setting process can be achieved by heating with an appropriate thermal shape setting fixture and at a temperature of about 400°C - 600°C, for example, about 500°C.

[0084] The filter assembly may be asynchronously displaced (out of phase) with respect to CO, which helps to remove the amplification of frame displacement caused by CO. The articulation points can be set to vary the curvature and rigidity so as to conform to a regulated geometric shape across various types of aortic arches. This easily enables a dynamic adaptation / seal to the variously changing diameters of the AA. For example, the CW force affects the AA after deployment. The articulation also balances the movement of the delivery shaft (reducing the influence of the user's movement), approximates and adapts to the curvature of the AA, minimizes its dimensions during retraction within the catheter, and reduces its shape.

[0085] As described herein, the strut may be implemented to facilitate the sealing of the filter to the sidewall. The ratio of the cross-sectional height to the width is referred to as alpha and can be used to characterize the overall frame stiffness and the directionality of the forces generated by the frame. For applications with a robust frame, alpha > 2 can be used. For intermediate stiffness, alpha can be between about 1.5 and 2 and can be applied to applications where the regulation of the appropriate cardiac output (CO is 4 - 5 liters / min) and / or geometry is slightly less and the transition region across the artery is smooth (fewer sharp curves than in AA). A more robust frame can accommodate a moderate mesh buoyancy inside the catheter, a thinner / lighter mesh, and friction. For low stiffness, an alpha between about 1.25 and 1.5 can be used and can be used to provide a heightened sensitivity to forces generated by the mesh in applications with a low cardiac output (CO < 3.5 liters / min) and / or geometries with very steep transition regions across the artery, as well as in a low friction and hemodynamic environment inside the catheter.

[0086] Accordingly, the combination of axial, lateral, and torsional forces on the frame assembly may form a separation / damping system (e.g., similar to an automotive suspension system) such that the frame assembly functions to seal against the hemodynamic forces of blood. The combination of the seal rail and strut controls lateral and torsional forces. The shape and dimensions of the separation region control axial and perpendicular forces. The natural frequency of the frame assembly can be used as an indication of how the damping system is functioning. The higher the natural frequency of the FA, the better the seal against the arch. A continuously varying stiffness can be used with the FA from the start to the proximal end of the separation region with respect to the feed shaft, providing a more natural cushion during cardiac output and the resulting aorta pulsation. Also, it provides "proximal" with respect to the actual curvature of the aortic arch. The value of the stiffness of the FA increases from the distal end towards the proximal end of the feed shaft, and the combination of the stiffness of the frame assembly is always less than the stiffness of the feed shaft. The combination of the mechanical forces of the FA and the mesh hemodynamic mesh is greater than the hemodynamic forces due to cardiac output and is offset with respect to the frequency of cardiac output.

[0087] Various types of articulation features can be used to facilitate the deployment of the FA and a better seal. One includes the mechanical articulation of the FA itself that better conforms to the more restricted and shorter length of the aortic arch. Others include the articulation of the separation region or the extension arm from the proximal end of the frame to the connection to the shaft. The articulation can be used to better pass through bending and provide a positive clockwise force against the wall of the aortic wall. Still others include material stiffness. The combination of axial and longitudinal forces on the frame determines the stiffness of the strut and, thus, the resistive force against hemodynamic forces.

[0088] The various aspects of the frame described herein may be implemented by axial features such as the following. The apparent length radius of the frame corresponds to the shape regulating force when deployed within the living tissue of the curved aortic arch. The radius of the aortic arch is smaller than the radius of the frame. This is used to provide a regulated state and build the potential energy within the frame structure due to the small radius of curvature of the aortic arch. If the living tissue permits, the potential energy is released into kinetic energy through the movement of the arcuate portion, correcting the frame. This movement maintains the seal contact with the living tissue and the longitudinal rigidity in the blood flow.

[0089] The various aspects of the frame described herein may be implemented by radial features such as the following. The specific width of the frame starts from two pivot points at each end of the frame structure respectively. These pivot points initiate the spreading movement regarding the radial coverage rate of the filter. The apparent width of the frame is larger than the diameter of the aorta. When the frame is regulated by the living tissue, potential energy is accumulated. If the living tissue permits, the potential energy is released into kinetic energy through the dilation of the aorta, and the frame expands to its apparent state. This movement acts to maintain the widthwise coverage rate of the filter and support the seal contact with the living tissue.

[0090] The various aspects of the frame described herein may be implemented by lifting characteristics such as the following. The shaft, the extension arm, and the frame structure are each configured to apply a lifting force to the frame, which facilitates the interaction with the side wall of the aortic arch. Regarding the specifications of the components, this stored energy is generated by utilizing the material properties of the shaft and the dimensions of the living tissue. If the living tissue permits, the potential energy is released into kinetic energy through the movement of the arcuate portion, and the frame structure is supported.

[0091] The various aspects of the frame described herein may be implemented with the following pulse characteristics. As an extension of the radial vector, the apparent shape of the frame structure applies a force towards the wall of the aorta for sealing. During the cardiac cycle, and the associated expansion and contraction of the aorta, resistance (from potential energy to kinetic energy) maintains contact of the aorta wall based on the force, and thus maintains the seal throughout the dynamic cardiac environment.

[0092] In various embodiments, various types of filters can be used. The filter mesh may be implemented with the following behaviors, physical and mechanical properties, porosity, and chemical and hemodynamic effects. Further, the chemical, biological, and geometric aspects of the mesh can be combined with the general properties of the mesh to be suitable for a particular application. The mesh may comprise a thin metal or plastic film wound around and / or attached to the periphery of the frame assembly as described herein. The mesh may be wound around the periphery and support extension of the frame at the proximal end. This generates a mechanical sealing force that can overcome the hemodynamic forces applied to the frame / mesh assembly. The filter mesh is used to provide the frame assembly with a reinforcing and containment structure, and a filter mechanism that blocks and deflects embolic particles of inappropriate size from the main aorta. The plastic mesh may be extruded, adapted, inflated, woven, or tubular. The plastic mesh can be formed from polypropylene, polyethylene, nylon, PVC or PTFE, a thermosetting resin or a thermoplastic material. The metal mesh is woven, knitted, welded, inflated, photochemically etched, or electrocast (screen filter) from steel or other foreign metals for TAVR applications. The thickness of the mesh is also important and contributes to the weakness or strength of the mesh against the pushing or pulling forces of the frame assembly.

[0093] The functions of the filter mesh in TAVR applications are: a) to block and divert unwanted emboli; b) to allow minimal occlusion and resistance to flow in three arteries; c) to provide sufficient flexibility inside the catheter (to obtain the minimum amount / crushed dimension) and outside the catheter (to allow and not restrict the movement of the frame); d) to provide sufficient resistance to shear forces (tearing); e) to provide maximum porosity to reduce flow resistance; f) to have strong self-adhesive strength; g) to resist biopflow in blood flow; h) to have buoyancy with respect to blood density (thereby increasing the sealing force of the frame); i) to be stretchable (following the cardiac cycle and its dynamic movement within the catheter with respect to the frame structure); j) to be hydrophobic; and k) to be physically, chemically, and inert with respect to the hemodynamic environment, including.

[0094] Figure 17 shows related embodiments that can be implemented by a frame and a porous filter assembly. The mesh film can be fully fixed to the frame without inhibiting its dynamic movement and sealing function. The flexibility of the frame and mesh assembly allows for sealing against many subsets and combinations that can occur in any of the geometric shapes of the type I, type II, or type III aortic arch.

[0095] Figure 18 shows the through-cell shape of the film and the percentage of the opening with respect to the total area (% porosity) that can be implemented in one or more embodiments. For example, the hexagonal cell shape of the through-thin film can achieve a porosity of 50% or more when patterned in one direction. Various examples provide the maximum possible porosity and minimize the resistance to blood flow and flow rate when blood enters the artery. As the porosity value increases, the distance between each cell becomes shorter, and as a result, the shear stress generated by stretch or tensile force may increase, causing the thin film to tear. The shear stress is inversely proportional to the thickness of the mesh film. The smaller and narrower the space between each cell, the greater the shear stress generated in the mesh due to sliding or friction against the metal frame, as well as pulling, stretching, and bending. Therefore, various examples use films set according to these aspects.

[0096] The range of filterable particle sizes according to the embodiments herein can be classified into multiple groups, and each group is defined by the size relative to the pores of the membrane. One group includes larger particles (too large to fit into any randomly dispersed pores or fiber matrix), and another group includes particles small enough to pass through the large pores or fiber gaps of the membrane but not through the small pores or gaps. In a filter, the size axis of the particles that matches the function of the pores is set to fit the desired particle size for the filter. The blood flow rate, viscosity, and probability coefficient due to dragging (e.g., the axial arrangement of the particles) result in a more elongated shape (needle shape) that passes through or crosses obliquely through the opening. Therefore, in a mixture of particles generally considered too large to pass through the pores or gaps of the fiber matrix, depending on how the flow pattern is directed by the filter state or by chance, certain shapes may allow them to pass through.

[0097] Therefore, FIG. 18 shows a general geometric shape pattern corresponding to a filter in which the cell size, shape, and porosity can be designed for each functional requirement of the plug capture technique. The particle size and shape are thus used for filter efficiency for a specific particle size, and the effective filter area (EFA) is marked by the pore size or retention distribution for the particle size distribution. The filter efficiency h is related to the beta ratio BX, which can be defined as the number of particles before (NIN) and after (NOUT) the filter related to a specific particle size (x). [Eq. 8] BX = BIN / BOUT Therefore, the filter efficiency h (%) is [Eq. 9] h (%) = 100 - (100 / BX) and is related to the beta ratio (BX) as follows.

[0098] As BX increases, the efficiency accordingly improves. For example, when BX = 200, h = 99.50%, and when BX = 1000, h = 99.90%. The distribution density function determines the mean and peak (BX) of the number of particles. The probability distribution function (PDF) for a property quantitatively defines how the values of the property are distributed among the particles in the entire population. Distribution functions based on several experiments can be implemented to very accurately represent the size distribution in many actual particle populations, and these are useful in some embodiments. Examples of functions implemented in one or more embodiments include the following. a. [Eq.] the Rosin-Rammler distribution function defined by, where D = 63.2 is the size at which the distribution function has a value of 0.632. b. [Eq.] the lognormal distribution defined by, where G(x) is [Eq.] [Number] It is a function defined by, and is called the Gaussian or normal distribution function. This is tabulated in many mathematical and statistical reference books, and it is easy to obtain values for this function. In this distribution, D50 is the particle size and PD50 = 0.5. This is called the median dimension. c. [Number] It is the logistic distribution defined by. These three distributions are two-parameter functions and can closely fit how they are distributed by the measured size and curve fitting techniques. Therefore, by determining the particle distribution for each characteristic (size, shape, mass, velocity, etc.), the most likely particle distribution for evaluating filter efficiency can be determined and can be used to set the features described in various embodiments.

[0099] FIG. 19 shows elements to be considered when setting the pore size according to one or more embodiments. The pore structure of the fabric or plastic film can be changed according to the use of the film. The cross-section of the pore may be an ellipse having a minor axis d and a major axis (n*d). By assigning different numbers to the axis ratio n, various pore cross-sections can be represented. For pores having an elliptical cross-section, the measured pore diameter is D, [Number 15] D = 4d / [8(1 + n 2 ) / n 2 1 / 2 can be estimated as such. For example, for a pore size of 125 microns and n = 1, 1.5, and 2, the particle sizes that cannot pass through are thus 125, 147, and 158 microns. The largest particle that can pass through the elliptical pore is d. The ratio of the diameter d of the largest particle that can pass through and the measured pore diameter D is the pore shape coefficient, [Number 16]​ λ = [d / D] = [(1 + n 2 ) / 2n 2 1 / 2 is given by

[0100] FIG. 20 shows pore shape factors approximating various cell shapes that may be implemented in one or more embodiments. FIG. 21 shows a comparison of the maximum diameter of particles that can pass through pores obtained from the fiber diameter and mesh count of a fabric and the pore diameter measured with a porometer. The mesh performance within the catheter and its response to friction and dynamic loading can be varied prior to deploying the frame and mesh assembly within the aortic arch. According to one or more experimental embodiments, the average size of the openings of a polyamide fabric calculated from the fiber diameter and mesh count is in good agreement with the largest particle that can pass through calculated from the pore diameter measured with a porometer. The measured pore diameter can be made comparable to d by including a multiplication factor.

[0101] The mechanical properties of the film (or fabric / non - woven material) can be used to determine a first aspect of the filter properties. These properties include yield stress, strength (area under the stress / strain curve), strain, elastic energy coefficient (elastic energy coefficient = (yield stress) 2 / 2 * Young's modulus), hardness (energy of mechanical deformation / volume), and density. The properties of the perforated film or fabric may include stretchability, flexibility, and tear resistance. The film properties related to one or both of the physical or geometric shapes (of the mesh) can be set to be suitable for a particular application.

[0102] ​The stretchability of the perforated film or fabric can be defined as the combination rate of film stretching and direction with respect to the original length (e) before exceeding the linear stress limit of the material. When the stress limit is reached, shear stress, tearing at the cell position, and further maximum shape change (β) of the mesh cell may occur due to stretching (s = ε + β). The strain (ε) of the material is defined by dividing the ratio of movement by the reference length and is related to the inherent properties of the film material. The shape change β is related to how much it is stretched / extended with respect to the original hole size (β = 1 - L0 / LS) before reaching the maximum stress that causes tearing in the material near the geometry of the mesh and the cell position. Therefore, various embodiments are targeted at reducing shear and tearing.

[0103] Figure 22 shows the elongation characteristics of the holes that can be implemented in one or more embodiments. Tearing occurs due to either β or ε depending on the amount of elongation or the value of strain. For thick films with high yield, ultimate stiffness, hardness, and low porosity (less than 25%), shear stress and tearing due to material strain are likely (polyester mesh with low porosity). In contrast, when the mechanical properties of the material are low but the thickness and porosity are the same, cell tearing occurs due to cell shape deformation and elongation (β). Therefore, the filter design is implemented to solve potential problems in this regard.

[0104] The flexibility of the filter implemented in the embodiments herein can be set to conform to a specific application. The flexibility of the perforated thin film is the ability to elastically deform the material and return to its original shape when the applied force is removed or reversed. The film elastically adapts to external changes (folding, bending, twisting). The more flexible an object is, the lower its rigidity. The flexibility of the perforated thin film causes a very small strain (ε = 0) in the material during shape changes (the internal stress of the film can be ignored). This is due to the shape change of the film and the ability to bend and move within many degrees of freedom. Flexibility can be quantified very mechanically as the reciprocal of rigidity (1 / K), where K = force / deformation. However, for thin, flexible, and perforated films, other factors may also be involved. Thermoplastic or thermosetting thin films, for example, can be folded under their own weight. When held on one side, the perforated thin film folds and bends, changing its shape due to gravity. It can be twisted multiple times while held on one side before elongation and stress cause shear stress and tearing. Therefore, the definitions of foldability (NF), bendability (NB), and twistability can be incorporated to define how flexible the perforated thin film can be. Also, it is obvious that as the porosity ratio increases, the thin film can adapt to more external changes (conform to more degrees of freedom). The specific gravity of the film material is also a factor in a buoyant or gravitational environment of fluidity. Bendability (NB = r / t) is defined as the ratio of the minimum bending radius (r) to the film thickness (t) that does not cause tearing or permanent strain in the film. Foldability (NF) is defined as the maximum number of times the length (L) of a thin film piece can be folded in half in the same direction. For a single-direction fold, the exact and necessary length (L) of the piece is

Number

[0105] The upper bound and approximation of the actual paper width required for folding in alternating directions are [Number] where W is the width of a square piece of paper of thickness t, and n is the desired number of folds made in alternating directions. The above equation gives an approximation N F for the thickness and length of a thin material. However, the actual value can be determined experimentally.

[0106] Torsionality (NT) is the maximum number of turns by which one side of a thin film can be twisted in the same direction before elongation or stress is produced in the film. One twist is equal to a 360-degree rotation about the axis of symmetry of the film. During twisting, the initial length of the film shortens as the number of twists increases, without the overall twisted object starting to bend, until the film can no longer be twisted further. In summary, the flexibility (FL) of a perforated thin mesh can be defined as the product of factors as described above. Thus, the б, dilute porosity, and specific gravity of the thin film are [Number 19] FL = б * r * NF * NB * NT is.

[0107] Tear resistance is the ability of a material to resist shear stress. Thermosetting materials can have high yield stress and modulus of elasticity. Thus, their resistance to tearing is high compared to thermoplastic substances. In the analysis of the maximum shear stress of a material due to an external force, the stress concentration factor (KF) due to the shape of the holes is considered. Circular holes have a smaller stress concentration factor compared to hexagonal ones. Hexagonal holes with six vertices are vulnerable to high stresses during shape changes (such as bending, buckling, and elongation) compared to circular ones. The tearing force (F) is [Number] estimable as follows, where S is the shear strength of the film, T is the thickness, L is the length of the film, and KF is the stress concentration factor (which can be determined analytically or experimentally).

[0108] The biodegradation characteristics of the filter material can be set to solve specific embodiments and examples. Biodegradation in a biological environment may be defined as the gradual destruction of a material by specific biological activities. Oxidation, hydrolysis, and enzymatic mechanisms can occur in biodegradation. When the material is exposed to body fluids, changes in physicochemical properties can occur due to chemical, physical, mechanical, and biological interactions between the material and the surrounding environment. The biodegradation process proceeds through chemical, physical, and biological interactions. The biodegradation rate in tissue is related to the filter (e.g., polymer) characteristics and the location in the body where the filter is exposed. Chemical biodegradation is affected by composition, molecular structure, polydispersity, crystallinity, surface area, hydrophilicity, or hydrophobicity. Generally, chemical biodegradation causes the decomposition of the main polymer chain by random cleavage of covalent bonds, crosslinking or depolymerization of linear polymers, interference with regularly arranged chains and crystallinity, and reduction of specific mechanical properties. The decomposition can be surface decomposition or bulk decomposition. In the case of bulk biodegradation, water uptake by hydrophilic polymers is faster than the rate of conversion of the polymer to water-soluble materials, and bulk biodegradation causes the collapse of the entire material because the biodegradation process occurs throughout its volume. Surface biodegradation appears in hydrophobic polymers without damage to the internal structure, and these polymers provide good control of the degradation rate. The biodegradation characteristics can be set to facilitate interaction with the immune system and cells specialized for it.

[0109] Figure 23 shows the biological reaction of the material, which can be considered in relation to the selection and implementation of the filter material. The blood compatibility of the biomaterial can be set to facilitate the overall success of the biomaterial in the body. The implanted biomaterial may cause an immune reaction by the host tissue. The mechanical and physical properties of the film can thus be set to be inert in the presence of blood PH and viscosity. The polymer materials that can be implemented in various embodiments can generally be classified into three different classes depending on their raw materials: natural posters obtained from natural raw materials including both plant and animal origins; synthetic polymers based on completely synthetic raw materials; and biologically inspired polymers including synthesized materials that mimic but are not necessarily identical to naturally occurring polymers. Blood-material interactions result in a series of complex events including protein absorption, platelet adhesion and activation, coagulation, and thrombosis. For example, platelet adhesion and activation on the surface of the biomaterial are affected by surface characteristics such as energy, charge, and composition. The reaction intensity depends on many factors including the properties of the material itself. The hemodynamic response to the biomaterial follows different pathways. Coagulation, thrombus formation, and platelet adhesion immediately follow protein absorption by the film. This is affected by the amount of fibrinogen that can occur naturally on the biomaterial such that platelet and leukocyte adhesion are affected by the layer of absorbed protein, but they are restored by signals released by activated platelets and damaged cells.

[0110] FIG. 24 shows an approximate time scale of protein absorption, platelet adhesion, and leukocyte adhesion during an immunological reaction to a transplanted biomaterial and can be used for setting material properties according to one or more embodiments. FIG. 25 shows the surface compatibility of monolayer deposition of various activating factors on the surface of a polymer and the effects of various surface activities of the polymer's blood compatibility that can be considered in the filter design in various examples. The two different pathways of coagulation (complement and platelets) are not independent of each other. When coagulation occurs through the extrinsic pathway, the intrinsic pathway also contributes to thrombosis and plays an important role in the transmission of the reaction. Leukocytes and platelets co-stimulate each other. Activated leukocytes promote an increase in platelet aggregation, which in turn increases leukocyte activity. Thus, leukocyte adhesion and activation affect platelet adhesion and activity, which affects the coagulation cascade. However, in biomaterials, this reaction induces biodegradation and a persistent inflammatory reaction of the material. Thus, the heavy rigid film is activated (either on the surface or in the bulk) against coagulation and formation of blood sludge on the surface or clogging of the pores of the filtration mesh. The wettability and its affinity of the surface for attracting and attaching blood particles are another aspect of compatibility that can be considered in filter design. Surface functionalization can thus be selected to allow capture of the porous medium by emboli or continuous impact, but to mitigate or prevent biodegradation.

[0111] Techniques for modifying a polymer membrane having improved blood compatibility include: a. modifying the bulk of the polymerizable material and then preparing the modified membrane; b. surface modification of the prepared membrane; c. blending, which can also be referred to as surface modification. In-situ cross-linking polymerization can be used to modify a PES membrane using different monomers of AA, VP, and NaSS at the same mass ratio.

[0112] FIG. 26 shows the coagulation time for materials that can be implemented in one or more embodiments. The anti-coagulation properties of the membrane can thus be evaluated by the activated partial thromboplastin time (APTT) and the thrombin time (TT). The activated partial thromboplastin time (APTT) and the thrombin time (TT) for membranes modified by PAA, PNVP, NaSS, and copolymerization are shown.

[0113] FIG. 27 shows a comparison of the mechanical properties of selected polymers that can be implemented in one or more embodiments. Exemplary properties include resistance to tearing, higher ultimate strength, elongation before failure, and modulus of elasticity. In addition to the above properties, properties that depend on bulk, surface, and geometric shape are important for applications including embolic protection devices. These additional properties include resistance to biofouling, biocompatibility, flexibility, foldability, and the ability of the material to bond to itself without the assistance of a second liner. The last category facilitates the polymer assembly to fix itself to the frame structure without causing additional bonding and indirect capacitance.

[0114] Various techniques and devices can be implemented for the manufacture and implementation of the filter assemblies described herein. FIG. 28 shows a fixture for frame manufacturing that can be implemented in one or more embodiments. The fixture comprises parts corresponding to the frame and the extension arms for the geometry to facilitate the application of the filter for adaptation to the side wall of a tubular tissue such as the aortic arch.

[0115] FIG. 29 shows a device comprising a frame and extension arms that can be implemented in one or more embodiments. For example, using a device such as that shown in FIG. 28, the device of FIG. 29 can be manufactured. The upper left top view shows the filter section (inside / outside) between the struts. The lower left side view shows the frame and extension arms that can be inserted into the aortic arch such that the bending of the extension arms interacts with the side wall. A detailed cross-sectional view is shown at the lower left.

[0116] Figures 30, 31, and 32 show manufacturing members for forming a frame, which can be implemented in one or more embodiments. Figures 30 and 31 show respective aspects of fixtures (e.g., lower / upper parts with respect to FIG. 28) that can be implemented together for frame formation, and FIG. 32 shows a curved portion that can be implemented with an extension arm. FIG. 33 shows an extension arm and a frame in a planar state, which can be implemented in one or more embodiments.

[0117] FIG. 34 shows a diagram of an apparatus including aspects for forming an extension arm and various cross-sections. FIG. 35 is a manufacturing fixture that can be implemented in one or more embodiments and supports aspects regarding the manufacture of a frame and an extension arm that can be implemented in one or more embodiments.

[0118] In accordance with one or more embodiments, the filter device can be implemented during surgery from the aortic arch such that the plug eases or prevents the passage of the plug through large blood vessels (brachiocephalic / innominate artery, left common carotid artery, and left subclavian artery). The aortic arch is part of the main artery that bends between the ascending and descending aorta. The aortic arch rises away from the heart and then descends to form an arch. The aorta pumps blood from the left ventricle of the heart to the rest of the body and exhibits various flow characteristics in a state where the hemodynamics in the aortic arch region often shows a non-uniform distribution of pressure and velocity. Particles such as emboli function as a filter umbrella and are filtered under such conditions using a filter member that conforms to various geometric shapes of the aortic arch during periodic pressure changes. The collected emboli are extracted and removed outside the body via a delivery tube, such as by crushing the filter member and drawing it into the sheath.

[0119] In certain embodiments, the filter mechanism described above comprises a main frame assembly (FA) and a mesh umbrella that are fixedly attached to the frame. The frame and mesh may be integrated as one piece / member or as two or more pieces / members. The FA operates to provide a mechanical seal near the opening of the inner wall of the vascular tissue with the FA in a state adapted to the wall. Thus, it is possible to prevent microemboli and other particles from entering the opening without restricting the blood flow within the vascular tissue to which the FA adapts. In various examples, the FA is operable to maintain adaptation and mechanical sealing under periodic blood pressure changes related to various ecological structures and conditions, including humans under various conditions related to surgical procedures, and various ecological structures and conditions related to changes in the size or accumulation of the aortic arch and / or plaque. For example, the mesh may be deployed in an area at least twice as large as any one or more openings being covered. Thus, various aspects of the FA may be implemented to facilitate such capture via catheter deployment during surgery in a state operable to capture particles such as collapsed / microemboli and move the particles into the catheter for removal upon completion of the surgery. Also, by controlling the pressure via mechanical spring force, it is possible to avoid the application of too high a pressure, which is useful in scenarios where hardening of the blood vessel wall and aneurysms may be present.

[0120] In another exemplary embodiment, the apparatus comprises a catheter extending from a proximal end to a distal end, a shaft operable to move within the catheter, and a filter member connected to an end of the shaft and operable to extend from or retract to the distal end of the catheter. The filter member comprises a mesh, and inner and outer frames, the inner and outer frames being connected to struts and to which the mesh is coupled to either or both of the inner and outer frames. The outer frame extends along an inner frame (e.g., in a concentric arrangement). The struts operate to apply a force between the outer and inner frames mainly in a direction (tending to push the frames apart from each other) between the frames. The frames may be elliptical, circular, or rectangular, with the latter approach facilitating the realization of a flat surface for applying pressure to tissue. One or more of the mesh, frames, and struts can be formed from a continuous material. In various embodiments, the struts apply a force that presses the inner frame and the mesh against the tissue, such as against the inner region of the vascular tissue. A configuration such as a brush can be used in the peripheral region to facilitate sealing.

[0121] As described herein, the techniques are particularly useful for deploying a mesh against the inner wall of the aortic arch and sealing around one or more of its arterial openings with the mesh. The deployment may include, for example, restricting the movement of the filter assembly through the catheter / shaft to rotational movement, which facilitates the application of pressure to the mesh against the tissue wall. Further, these techniques can facilitate insertion and filtration while conforming most of the mesh and support structure to the side walls of the aortic arch, allowing blood to flow freely while capturing particles that can enter one or more of the covered arteries. For example, it can allow human red blood cells to pass while minimizing the passage of particles having a size larger than human red blood cells. These particles are captured within the mesh / frame such that the particles are removed without further escaping into the blood stream.

[0122] The mesh can be sealable to the inner vessel wall or other tissues in various ways. In some embodiments, the struts operate with an inner frame, an outer frame, and the mesh, and in the deployed state, use the force applied to press the peripheral region of the mesh against the inner vessel wall to seal the peripheral region of the mesh against the inner vessel wall. This may include, for example, applying forces along various struts at different adjacent regions between the inner and outer frames such that the distance between the frames varies in response to the tissue structure of one or both of the frames. This flexibility allows sufficient sealing force to be applied along the peripheral region while absorbing differences in body structure.

[0123] In various examples, the mesh has opposing faces and is configured and arranged with a shaft, a frame, and struts to conform to the inner wall of the vascular tissue and cover at least one opening within the vascular tissue. One or substantially all of the opposing faces can contact the wall or extend over at least one opening. This mainly facilitates the placement of the mesh outside the blood flow within the vascular tissue.

[0124] In these and other situations, the deployment of the mesh is affected by the filter member, the shaft, and the catheter by inflating the mesh to a first state in response to the filter member extending from the distal end of the catheter and collapsing the mesh to a second state in response to the filter member retracted into the catheter. Thus, the mesh can be collapsed for fitting within the catheter and inflated by deploying with a much wider (e.g., more than twice the diameter of the catheter) covering for the filter.

[0125] Force can be transmitted in various ways by a filter member. In some embodiments, the filter member comprises a mechanical spring coupled to the distal end of a shaft. The mechanical spring operates based on the shaft and catheter such that a spring force is applied to direct the mesh towards tissue. For example, the mechanical spring can operate with the catheter and shaft such that a spring force in a direction towards the inner frame is applied to the outer frame while force is transmitted from the outer frame to the inner frame via a strut. In some examples, the spring applies force directly to the inner frame. The spring may be separate from or integral with (or part of) a support structure connecting the filter member to the shaft. The technique can be used to apply a catheter within the human aortic arch, seal a mesh against the inner wall of the aortic arch, and cover at least one opening in the human aortic arch with the mesh.

[0126] The meshes or other filter materials described herein can be implemented in various manners. In some embodiments, the mesh comprises a reinforcement structure and is operable to fold into and deploy from an overlap layer for each of retraction and deployment within a catheter. The reinforcement structure may include additional material over or within the mesh and regions that exhibit low rigidity during folding, for example. For example, the mesh may be patterned with different sized holes and / or hole densities to facilitate longitudinal or transverse folding / stacking behavior. A helical pattern can facilitate a particular opening and closing behavior. Regions with few or no holes can be implemented to create reinforcement moments.

[0127] Referring again to FIG. 1, there is shown an apparatus 100 that may be implemented to support a filter or mesh according to one or more exemplary embodiments. The apparatus 100 includes an inner frame 110 and an outer frame 120 coupled by a strut 130 operable to apply a pushing force to separate the inner and outer frames. A proximal end 140 is operable to be coupled to a shaft and is coupled to a distal end 150 through the frame. As an example, the illustrated distal end 150 extends at an angle relative to the inner frame 110, thereby facilitating positioning within the vessel wall (e.g., the inner frame 110 is pressed against the inner wall within the aortic arch). The angle may facilitate placement of the device within the aortic arch while avoiding entry of the distal end 150 into the artery within the wall. In certain embodiments, a cover such as a thermoplastic sheath may be disposed on the distal end 150 to facilitate interaction with the vascular tissue.

[0128] In certain embodiments, the proximal end 140 includes a mechanical spring (e.g., integrated with the illustrated structure) that provides an upward (illustrated) spring force capable of facilitating pressing the inner frame 110 against the inner wall of the blood vessel. For example, with the proximal end 140 coupled to the shaft and inserted into the vascular tissue via a catheter, the shaft and proximal end 140 can apply a spring force that tends to push the inner frame 110 upward and press it against the inner wall of the vascular tissue. The technique is particularly useful, for example, within the aortic arch. In some examples, both frames are pressed against the inner wall of the vascular tissue. With the mesh coupled across the perimeter of the inner frame 110 (and in some cases, across the overlapping perimeter of the outer frame 120), blood flowing through the holes in the inner wall perimeter of the inner frame is thus filtered by the mesh. The mesh may be implemented, for example, with the configuration indicated by 160 (partially illustrated with the mesh occupying the entire inner region around the inner frame 110). Also, the spring force of the proximal end 140 can be used to maintain a seal against the vessel wall in various blood flow conditions and various biological tissues.

[0129] In various embodiments, the mechanical force applied via the spring and / or strut 130 can be implemented as a major force that adapts the structure to the inner wall (e.g., a mechanical force several times greater than the fluid force of blood passing through the blood vessel). This force can be adjusted, for example, during the manufacturing process to be adapted to a specific application. For example, the force may be increased or decreased based on the patient's age and the condition of the wall where the mesh is to be deployed, such as the size and presence of plaque. Control of the adhesion force can facilitate optimization of the mesh dimensions so that the mesh is not oversized in stabilizing any such force.

[0130] The device 100 may be composed of one or more components. In some embodiments, the inner frame 110, the outer frame 120, and the strut 130 are formed from a continuous material and do not require bonding. Also, in various embodiments, the mesh (e.g., 160) bonded across the inner frame 110 is formed with at least the inner frame 110 of a continuous material. For example, a continuous nitinol material may be used to form one or all of the components of the device 100. In some embodiments, a thin thermoplastic material is used as the mesh and bonded to the inner frame. When two components are used, they can be integrally joined using a joining method including one or more of heating and pressing, adhesion, and laser. The frame and strut can be formed using a polymer material and / or a metal material. The mesh can be directly attached to the frame and / or the mesh itself.

[0131] In various embodiments, a mesh such as the mesh 160 includes brushes such as teeth or grooves that improve the grip of the mesh on a rough area (e.g., the surface of the aortic arch). These brush features may be located in the area of the frame. Small features such as micro features (with respect to the blood vessel wall structure) are subject to spring forces and can be significantly compressed against the blood vessel, thereby sealing against the blood vessel.

[0132] In various embodiments, device 100 operates to maintain tissue under tension (e.g., along and into the interior of the vascular tissue) when the inner and outer frames 110 / 120 are deployed. In this situation, sufficient sealing pressure is applied to maintain a seal of the structure against the wall when blood is flowing through the mesh. This includes providing smooth surfaces that interact along the interface between the device and the surface of the tissue (e.g., the aortic arch). This approach can be implemented with few or no bumps or raised cross-sections by minimizing / making features such as welding, adhesion, overlapping, and "grooves", thereby facilitating a tight seal against the vascular tissue.

[0133] FIG. 2 shows a device 200 according to one or more exemplary embodiments of the present disclosure. Device 200 includes a filter member 210, which may be implemented by inner and outer frames with connecting struts as shown in FIG. 1. The filter member is connected to a shaft 220 (e.g., a shaft and catheter several times longer than the portion shown) that extends through a catheter 230. The proximal end 240 of the filter member 210 is fixed to the shaft 220 and provides a spring force in the upward direction shown, sealing the periphery of the filter member 210 against the vascular wall when deployed within the vascular wall.

[0134] Figures 3A through 3D are diagrams showing an apparatus 300 according to one or more exemplary embodiments of the present disclosure. As shown in FIG. 3, the apparatus 300 includes a filter member 310 coupled to a shaft 320 within a catheter 330, where the filter member is retractable within the catheter. The mesh may be coupled and / or integrated with the filter member 310 across each rail (e.g., as shown in FIG. 1). FIG. 3B is a cross-sectional view taken along “A-A” of FIG. 3A, and FIG. 3C shows the distal end of the catheter and the shaft coupled to the proximal end 340 of the filter member 310. In various embodiments, a portion of the proximal end 340 is disposed and fixed on the shaft 320 such that it does not extend beyond the end 350 of the catheter 330. Thereby, when disposed within the vascular tissue, the components are maintained within the catheter and outside the blood flow. FIG. 3D is a diagram of an alternative apparatus 300.

[0135] In various embodiments, a portion of the proximal end 340 is disposed and fixed on the shaft 320 such that it does not extend beyond the end of the catheter 330. When disposed within the vascular tissue, the components are maintained within the catheter and outside the blood flow.

[0136] FIG. 4 shows an apparatus 400 for supporting a mesh or filter that may be implemented in one or more exemplary embodiments of the present disclosure. The dimensions shown in FIG. 4 are an example and may be implemented with respect to a particular embodiment. The apparatus 400 includes an inner frame 410, an outer frame 420, and struts 430 that press the frames away from each other. Detail “A” provides an exemplary illustration of these members. The distal end 440 and the proximal end 450 are coupled to the frames as shown.

[0137] Figures 5A through 5C each show an apparatus 500 for supporting a mesh or filter that may be implemented in one or more exemplary embodiments of the present disclosure. Apparatus 500 may be implemented similar to the illustration of FIG. 4. As shown within the detail “A” of FIG. 5A, an inner (510) and an outer (520) frame are connected by struts 530 that space the inner frame away from the outer frame and press it against a blood vessel wall. FIGS. 5B and 5C are side and end views, respectively, of apparatus 500.

[0138] FIG. 6 shows a catheter apparatus 600 comprising a mesh 610 retracted within a sheath 620, according to one or more exemplary embodiments of the present disclosure. Mesh 610 may be implemented, for example, with a filter member as shown in FIGS. 1 and 2, and may be operable to fold and retract within the catheter. For example, the mesh may be deployed on the inner wall of the aortic arch and used to filter particles from the blood flow to the artery sealed by mesh 610, and then folded and retracted within sheath 620 as shown to capture and remove the particles. In various embodiments, mesh 610 has a reinforcement / rib structure that allows it to be folded or expanded in a particular desired direction when deployed or retracted within the sheath.

[0139] Figures 7A through 7G each show a filter support manufacturing apparatus 700 that may be implemented in one or more exemplary embodiments of the present disclosure. Each dimension shown is an example, and apparatus 700 may be manufactured in various dimensions. Apparatus 700 is used, for example, to manufacture one or more filter members as shown in other figures. Referring to FIG. 7A, an upper fixture 710 and a lower fixture 720 are shown in perspective views, and a forming region 722 is shown in the lower fixture and is operable to form a filter member.

[0140] Figures 7B and 7C are, respectively, an end view and a top view of apparatus 700 with upper and lower fixtures 710 and 720 positioned on the forming stage. Detail A-A from Figure 7B is shown by region 730 that provides a space between the upper and lower fixtures 710 / 720 for forming the filter member. The method can be facilitated by various molding methods.

[0141] Figures 7D and 7E are, respectively, a top view and a perspective view of lower fixture 720. As part of Figure 7D, cross-sections A-A, B-B, D-D, and detail C show various cross-sections and associated details. Region 730 is recessed to form part of the filter member.

[0142] Figures 7F and 7G are, respectively, a top view and a perspective view of upper fixture 710. As part of Figure 7F, cross-sections A-A and B-B show cross-sections, respectively. Region 740 is recessed to form part of the filter member.

[0143] Various other methods for manufacturing can be implemented to suit a particular embodiment. In some embodiments, the starting material is processed to form a mesh. For example, in some instances, a flat nitinol material is used and the mesh area is first reduced to less than 0.005 inches (or less than 0.001 inches) using electrical discharge machining (EDM) or other techniques. Next, the frame assembly and mesh pattern are cut, for example, using a laser. In some instances, the order of the process is reversed and the frame assembly (frame) is laser cut and then EDM and laser patterning are performed.

[0144] In various embodiments, a frame assembly, such as may be implemented by a frame / mesh support member shown in one or more of FIGS. 1-5C, has a rectangular cross-section that provides directional stiffness and higher forces than a circular cross-section. The rectangular cross-section provides a desired surface contact area and more distributed forces, facilitating sealing. A flat rectangular frame structure can be implemented by double frames and struts that hold tissue under tension (taut) in both the transverse and axial directions. This can facilitate a constant fluid pressure at the mesh and tissue arterial openings.

[0145] Referring to FIG. 8, an apparatus 800 is shown that may be implemented by various embodiments that include a filter. The apparatus 800 includes an inner frame 810 and an outer frame 820, and a mesh 860 that covers a main region within a perimeter defined by the inner frame and within a region 862 between the inner and outer frames. In various embodiments, two mesh layers are implemented, where a first mesh has a perimeter that is aligned with the perimeter of the inner frame 810, and a second mesh is overlaid on the first mesh and has a perimeter that is aligned with the perimeter of the outer frame 820. In various embodiments, the inner frame 810 and the outer frame 820 are pushed against the inner wall of the vascular tissue and operate to form a horizontal seal or double seal for filtering blood flowing through arteries in the inner wall. The apparatus 800 may be implemented, for example, by struts between the inner and outer frames as shown in FIG. 4.

[0146] In various embodiments, the frame assembly is designed to provide a spring constant of the frame assembly that includes a double horizontal seal around the main region. This improves the reliability of the seal, increases the force of contact against the inner wall of the tissue (e.g., the aorta), and results in a greater adhesion / cohesion force between the tissue and the layer. The frame structure may be implemented by spring members that facilitate the deployment and collapse of the mesh. The frame assembly may be formed from four layers for providing support forces for sealing, deployment, lateral forces, torsion, retraction, and restraint. For example, these aspects may be implemented by the device 800 shown in FIG. 8 or other filter components as shown in other figures.

[0147] FIG. 9 shows the brush features of a device 900 that may be implemented in one or more embodiments. For example, the features shown in FIG. 9 may be implemented by the mesh 160 of FIG. 1. The device 900 includes an inner frame 910 and an outer frame 920 that are coupled by struts 930 that tend to push the frames apart from each other. A mesh 940 (partially shown) is coupled to the frames, and brush-like features 950 are coupled to the mesh in the vicinity of the frames. The frames 910 and 920, together with the struts 930, apply an upward pressure to the mesh 940 and the brush-like features 950 as shown, for example, to seal the mesh against the inner wall of the vascular tissue (e.g., the surface of the aortic arch). The brush-like features 950 may be formed from the same material as the mesh 940 and are compressible to facilitate the sealing of the mesh against the inner wall.

[0148] Based on the above description and illustration, it will be readily understood by those skilled in the art that various applications and modifications may be made to the various embodiments without strictly following the exemplary embodiments and applications illustrated and described herein. For example, different types of materials may be used for the various components described herein, and other techniques may be implemented that provide asymmetry, flexibility, and adaptability that exhibit similar effects. Additional and / or different shaped frame portions or struts may be used, for example, to suit particular biological tissue applications by varying the asymmetry and / or rigidity in various states. Also, the various methods disclosed herein may be implemented by different types of tubular structures, arteries, and tissues, as well as different types of tubes and organisms. Such modifications do not depart from the true spirit and scope of the invention, which encompasses the aspects defined in the claims.

Claims

1. An extension arm, An asymmetric frame having a proximal end connected to the extension arm and extending to a distal end that extends away from the extension arm, the asymmetric frame having a narrow small region at the proximal end and a wide large region at the distal end, A filter having a surface region that terminates at a periphery of the filter and configured and arranged with the asymmetric frame and the extension arm to conform one of the surface regions to an inner wall of a tubular structure, Comprising, The asymmetric frame is asymmetric in the transverse direction and the longitudinal direction with respect to a longitudinal direction corresponding to the extension arm and a transverse direction perpendicular to the longitudinal direction and extending across the filter, Device.

2. The device according to claim 1, wherein the asymmetric frame is configured to have an asymmetry that conforms to an asymmetric structural characteristic of the inner wall of the tubular structure.

3. The device according to claim 1, wherein the asymmetric frame has an asymmetry that mimics an asymmetry inside the inner wall.

4. The device according to claim 1, wherein the asymmetric frame has a longitudinal asymmetry including an inner bend in a central region on a rear side of the asymmetric frame and an outer bend on a front side of the asymmetric frame.

5. The device according to claim 4, wherein the asymmetric frame has a longitudinal asymmetry such that a distance between a rear frame rail at the proximal end and a center line is smaller than a distance between a front frame rail at the proximal end and the center line.

6. The asymmetric frame, Including an inner bend in a central region on a rear side of the asymmetric frame and an outer bend on a front side of the asymmetric frame, Such that a distance between a rear frame rail at the proximal end and a center line is smaller than a distance between a front frame rail at the proximal end and the center line, Having a longitudinal asymmetry, The device according to claim 1.

7. The asymmetric frame has a transverse asymmetry including a distal end and a proximal end, the proximal end being coupled to the extension arm and the distal end extending away from the extension arm, Having a longitudinal asymmetry including one or more of an inner bend in a central region on a rear side of the asymmetric frame, an outer bend on a front side of the asymmetric frame, and a distance between a rear frame rail at the proximal end and a center line being smaller than a distance between a front frame rail at the proximal end and the center line, The device according to claim 1.

8. The apparatus of claim 1, wherein the asymmetric frame has an asymmetric characteristic configured to facilitate the peripheral distortion that adapts to the asymmetry inside the inner wall.

9. The apparatus of claim 1, wherein the asymmetric frame, when engaged with the inner wall, has an asymmetry that adapts the periphery of the asymmetric frame to the lateral angle of the aortic arch and the lateral displacement of the ostium of the brachiocephalic artery.

10. The asymmetric frame includes a proximal end coupled to the extension arm and extends to a distal end where the asymmetric frame terminates. The distal end is laterally displaced relative to the proximal end and also relative to the direction in which the extension arm extends. The apparatus of claim 1.

11. The apparatus of claim 1, having an asymmetric characteristic configured to facilitate the peripheral distortion that adapts to the asymmetry inside the inner wall of the human aortic arch.

12. The apparatus of claim 1, wherein the asymmetric frame has an asymmetry with a laterally narrow feature and an opposite laterally wide feature.

13. The apparatus of claim 1, wherein the extension arm is configured and arranged with the asymmetric frame to apply a force to the asymmetric frame that seals the periphery of the filter and the asymmetric frame against the inner wall.

14. The apparatus of claim 1, wherein the extension arm and the asymmetric frame are configured and arranged to seal the filter around the opening of the inner wall and filter the fluid flowing through the opening.

15. The asymmetric frame includes an inner peripheral member and an outer peripheral member separated by a gap. The outer peripheral member extends around the inner peripheral member. The apparatus of claim 1.

16. The apparatus of claim 1, further comprising struts connecting the inner peripheral member and the outer peripheral member.

17. The apparatus of claim 1, wherein the extension arm is configured and arranged with the inner peripheral member and the outer peripheral member such that the inner peripheral member and the outer peripheral member press respective portions of the filter against the inner wall to seal the filter against the inner wall of the tubular structure.

18. A portion of the asymmetric frame is separated by a gap and includes an inner peripheral member and an outer peripheral member that form a first portion of the periphery of the asymmetric frame. A second portion of the periphery of the asymmetric frame is a single member connected to both the inner peripheral member and the outer peripheral member. The apparatus of claim 1.

19. The apparatus of claim 1, wherein the asymmetric frame has different rigidity characteristics in different portions.

20. The asymmetric frame has different widths in different portions, and a thick portion of the asymmetric frame is more rigid than a thin portion of the asymmetric frame. The apparatus of claim 19.

21. The apparatus of claim 20, wherein the asymmetric frame has a plane, the thickness between the planes is constant, and the width of the plane varies.

22. The asymmetric frame has different geometric shapes in different portions, and the different geometric shapes result in different rigidity characteristics. The apparatus of claim 19.

23. comprising a proximal end and a distal end, wherein a first rail and a second rail are coupled to the proximal end and the distal end, respectively, and the filter extends therebetween, and a lateral flexibility of the first rail is different from a lateral flexibility of the second rail. The apparatus of claim 19.

24. The apparatus of claim 1, wherein the filter is configured and arranged with the asymmetric frame and the extension arm to expand to a deployed state with the asymmetric frame to conform to one of the surface regions and to collapse to a collapsed state to retract into the catheter.

25. The asymmetric frame includes a rail extending from the proximal end to the distal end, each of the rails having substantially the same length and different shapes from each other. The apparatus of claim 24.

26. providing an extension arm, providing an asymmetric frame including a proximal end and a distal end, mounting the asymmetric frame to a fixture that mimics a feature of an inner wall of a tubular structure, setting the asymmetric frame to a shape that mimics the feature of the inner wall of the tubular structure defined by the fixture, connecting the proximal end of the asymmetric frame to the extension arm having a distal end extending away from the extension arm, coupling a filter having a surface region to the asymmetric frame having the surface region terminating at a periphery of the filter, comprising wherein the filter is operable with the asymmetric frame and the extension arm to conform one of the surface regions to the inner wall of the tubular structure, and the asymmetric frame is asymmetric in a lateral direction and a longitudinal direction with respect to a longitudinal direction corresponding to the extension arm and a lateral direction perpendicular to the longitudinal direction and extending across the filter. A method of manufacturing the apparatus according to claims 1 to 25.

27. The provision of the asymmetric frame comprises cutting out a planar frame from a sheet, the method of claim 26.

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