Actuated expandable access thrombectomy catheter

Abstract

The invention is entitled "Actuated expandable orifice thrombectomy catheter." A clot retrieval catheter can have an expandable distal tip for restricting / impeding flow and improving aspiration efficiency, and a distally facing large orifice into which a clot or other obstruction can be retrieved. The tip can be formed by a distal ring of a petal or collar. One or more pull cables can be retracted to actuate and radially expand the expandable distal tip. The clot retrieval catheter can have a catheter shaft with increased flexibility features proximal of the tip. The catheter shaft can be a multi-lumen configuration with a large catheter lumen for passing through an adjunct and directing aspiration, and one or more guide lumens that can guide the pull cables to the petal or collar of the expandable tip. A flexible low modulus membrane can be disposed around the expandable tip and at least a portion of the catheter shaft.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 941,585, filed November 27, 2019, which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0003] The present invention relates generally to devices and methods for removing acute occlusions from blood vessels during endovascular medical treatment. More particularly, the present invention relates to a retrieval catheter having an expandable tip into which one or more objects can be retrieved. BACKGROUND

[0004] Clot retrieval catheters and devices are frequently used in mechanical thrombectomy for endovascular intervention in cases where a patient is suffering from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing a neurovascular bed using conventional techniques is particularly challenging because the target vessel is small in diameter, distal relative to the site of insertion, and highly tortuous. Traditional devices are often too large in profile, lack the deliverability and flexibility required to navigate tortuous vessels, or are not effective at removing clots when delivered to the target site.

[0005] Clots themselves can complicate the procedure by assuming a variety of complex morphologies and consistencies, ranging from simple tubular structures that take on the shape of the vessel to long, chain-like arrangements that can span multiple vessels at once. The age of the clot can also affect its compliance, with older clots tending to be less compressible than fresh clots. Experience has also shown that the mechanical properties of clots can be affected in significant ways depending on the nature of the interaction with the clot extraction device. Additionally, several mechanisms play a role in the strong adhesion of clots to the vessel wall. Breaking these bonds without damaging the delicate vessel is a significant challenge.

[0006] Delivery of an effective device to the small and highly branched cerebral arterial system remains challenging, and conventional clot retrieval catheters have a number of shortcomings. First, the diameter of the catheter itself must be small enough to avoid causing significant discomfort to the patient. The retrieval catheter must also have sufficient flexibility to navigate the vasculature and withstand high strains, while also having axial stiffness to provide smooth propulsion along the route. Once at the target site, the size of the typical object being retrieved from the body is significantly larger than the catheter tip diameter, making it more difficult to retrieve the object into the tip. For example, firm fibrin-rich clots are often difficult to extract because they can become aggregated at the tip of a traditional fixed-oral catheter. Additionally, this aggregation can cause other softer portions to be sheared off from the more firm regions of the clot.

[0007] Small diameters and fixed distal end sizes are also less effective at suctioning blood and thrombus material away during the procedure. The aspiration must be sufficiently robust so that any fragmentation that can occur as a result of the aspiration or use of a mechanical thrombectomy device cannot migrate and occlude the distal vessel. However, when aspirating with a fixed orifice catheter, a significant portion of the aspiration flow ultimately comes from the vessel fluid near the catheter tip, where there is no clot. This significantly reduces the aspiration efficiency, reducing the success rate of clot removal.

[0008] Accordingly, many catheter designs have been proposed with openings that can expand at the target site. When a clot is captured and aspirated proximally into a tip having a funnel shape, the clot can be progressively compressed during retraction so that the clot can be completely aspirated through the catheter and into a suction syringe or cannula. Furthermore, if the clot does collect in the funnel-shaped tip, the expanded opening can protect the clot and prevent it from fragmenting when the aspiration is maintained and the catheter is retracted into a guide catheter or external sheath.

[0009] However, any catheter design that attempts to overcome the aforementioned design challenges with an expanded distal tip or funnel structure needs to have the strength to grip the clot and exert a stable radial force in the expanded state. The same structure also needs to be flexible and resilient to withstand the severe mechanical strains imparted when navigating tortuous vasculature while in the collapsed state. The tip will also need to be actuated by the user in a consistent and repeatable manner when deployed from an access catheter or intermediate catheter, balloon guide catheter, or other such sheath.

[0010] The design of the present invention is intended to provide an improved retraction catheter with an expandable tip that incorporates these features to address the aforementioned deficiencies. SUMMARY

[0011] The design herein can be used in a clot retraction catheter that is capable of providing localized flow restriction / resistance within a target vessel while also having a large clot-facing opening. The catheter can be sufficiently flexible to be able to navigate highly tortuous regions of anatomy, such as neurovascular, to reach an occlusive clot. The catheter can also be compatible with relatively low profile access sheaths and catheters to achieve deliverability advantages.

[0012] Clot retrieval catheters can have a substantially tubular body with one or more internal lumens extending through the body. A large central catheter lumen can be configured for a guidewire, microcatheter, stent retriever, and other such devices to pass therethrough. The lumens can also direct suction to an expandable tip at the distal end of the catheter. The tubular body can terminate at a distal end, with the expandable tip being integrally formed or fixedly connected at the distal end. The tip can be configured to expand from a collapsed delivery configuration to an expanded deployed configuration when extended from an access catheter or an intermediate catheter at an occluded thrombus site. Expansion can be activated by a user with controls on a proximal handle of the catheter.

[0013] In some examples, the tubular body can have a series of annular ribs extending laterally to and from one or more axially extending longitudinal ridges at various lengths. The ribs and ridges can be integrally formed by laser machining or extrusion of a polymer tube. In another example, the tubular body can be a metal braid or coiled wire construction covered with or impregnated within a polymer jacket. The ridges can be fixedly connected to or integrally formed with a portion of the expandable tip.

[0014] The expandable tip disposed at the distal end of the catheter body can be actuated by a user to assume a radially expanded deployed configuration. The tip can be actuated by control members such as pull cables that can be tensioned or pushed by the user and connected distally to one or more members of the expandable tip. The pull wires can be composed of steel or high modulus polymers with sufficient axial stiffness such that both tensioning and pushing of the wire actuate the function of the tip. One or more pull cable guide tubes can be disposed around the circumference of the catheter body and can extend the length of the catheter axis. Each guide tube can have an internal tubular lumen sized to allow uninhibited relative motion of the pull cables. The pull wire guide tubes can be tangent to the inner or outer walls of the support tube, or they can be formed in a middle wall.

[0015] In some examples, the guide tubes can terminate proximally of the distal end of the tubular catheter shaft, flush with the distal end of the shaft, or further extend a distance distally of the distal end shaft. Distal cuts can also be machined or formed near the distal end of the catheter shaft and / or guide tubes to allow the pull cables to have a more gradual small expansion angle relative to the longitudinal axis. A proximal control handle or luer interface can allow the pull cables to be tensioned together such that a uniform and consistent radial expansion is imparted around the circumference of the expandable tip.

[0016] In an expanded deployed configuration, the tip can assume a substantially conical or funnel shape with struts forming a plurality of leaflets or a distal collar about the longitudinal axis that can define an open distal-facing opening for retrieving an occlusion. The leaflets can have distal peaks with a slightly oblique ring or petal shape for atraumatic contact with the vessel wall upon expansion. The leaflets can also overlap one another circumferentially so that adjacent leaflets can slide relative to one another. This configuration can impart enhanced flexibility to the tip by allowing twisting or bending motion in tortuous regions of the vasculature. The overlapping leaflets can also enable the tip to fold over on itself for low profile deliverability and when the tip is collapsed back into an outer sheath or catheter. The leaflets can be axially symmetric or asymmetric with the longitudinal axis of the catheter. The struts forming the leaflets can be connected at the distal end of the tubular body and the struts can be aligned with one or more of the axial ridges of the support tube.

[0017] In some examples, the plurality of leaflets can have one or more actuated leaflets and one or more passive leaflets. The actuated leaflets and passive leaflets can have distal peaks and one or more proximal joints connected to the catheter shaft. Each of the one or more actuated leaflets can be connected to a pull cable for actuating and expanding the expandable tip.

[0018] The connection between the pull wires and leaflets can have a variety of configurations so that the tip retains some lateral flexibility at the joints. The pull wires can be connected to the leaflets in a variety of ways. In one configuration, one or more tension members extend proximally from the distal peak of the actuated leaflet and terminate in an eyelet. The pull cable extending distally from the guide tube of the catheter body can terminate in an enlarged bulb at the distal most end of its extension through the eyelet so that the pull cable and strut of the leaflet are coupled but not rigidly connected. The less rigid connection can impart additional flexibility and the ability to locally deflect to the tip when bending, or when the tip is placed under compressive load during retrieval of a clot.

[0019] In other examples the bulb can be polygonal or non-spherical in shape so that other designs of the interface between the customizable expandable tip and the catheter body can be contemplated for customizing the bending stiffness. Another design can have a flexible articulating joint such as a pin connection between the leaflet strut and the pull cable extending distally from the guide tube of the catheter body. The articulating joint can define or bias certain bending planes of the catheter when delivered.

[0020] In some examples, at least a portion of the leaflets can incorporate a pattern that will increase flexibility, such as undulations or expandable cells. In one example, the leaflet strut can have a wave shape or have narrowed segments to improve the overall flexible tip structure.

[0021] The proximal joints of the leaflets can also be designed in a variety of ways to reduce stress and increase the flexibility of the tip. In a catheter shaft cut from a hypotube, the leaflets can be integrally formed at the distal end of the shaft. In another example, additional lateral flexibility can be obtained by cutting an anchoring slot proximate the distal end of the catheter shaft, the anchoring slot configured to axially constrain a leaflet anchor of a proximal joint of a leaflet. The leaflets can be longitudinally anchored within the anchoring slot. The slot can be machined through the wall of the catheter body to form a constraining structure for the anchor of the leaflets. The leaflets can extend distally and each leaflet can overlap one or more adjacent leaflets to form a flexible petal-like arrangement. The struts of adjacent leaflets can cross and be capable of relative motion such that the tip is unconstrained when deployed to or collapsed from an expanded deployed configuration. In this configuration, a pull cable extending through the catheter body can form a loop around adjacent leaflets at the crossover points of the leaflet overlap. The pull cable loop can engage the crossover points spaced 180 degrees apart such that tensioning of the pull cable can cause smooth and uniform deployment of the tip.

[0022] A flexible covering can be provided to sleeve at least a portion of the support tube and at least a portion of the strut frame of the expandable tip. The covering can be a membrane formed of a malleable elastomer that has the advantages of being soft and pliable, with resistance to tearing and puncturing from high failure strains. Alternatively, the covering can be one or more polymer jackets that can be fused together and adhered, reflowed, or stitched to enclose at least a portion of the tip. The membrane can also be coated with or made of an elastomer or similar material to provide a low-friction surface to facilitate navigation within blood vessels and other conduits.

[0023] In another example, a thrombectomy catheter can have a tubular catheter shaft and an expandable tip integrally formed at a distal end of the catheter shaft. The catheter shaft can have a distal end and a catheter lumen having a longitudinal axis extending therethrough. In some examples, the catheter shaft can have one or more pull cable guide tubes disposed about the circumference of the catheter lumen. The guide tubes can house one or more pull cables disposed within pull cable lumens in the guide tubes and operable to be tensioned by a user of the catheter using a proximal handle. In one instance, two pull cables can be spaced 180 degrees apart about the circumference of the catheter shaft.

[0024] An expandable tip can be integrally formed at a distal end of a catheter shaft. The tip and shaft can be formed from a single polymer extrusion or a metal tube. The extrusion can be made, for example, from polyether ether ketone (PEEK) or another rough thermoplastic polymer. The extrusion can also be laser cut with transverse and / or axial slots to increase the tube's flexibility. In one example, the expandable tip can have a plurality of leaflets configured to radially expand from a collapsed delivery configuration to an expanded deployed configuration when one or more pull cables are tensioned. The expandable tip can be at least partially enclosed by one or more outer jackets.

[0025] In a more particular example, the plurality of leaflets can be two actuating leaflets connected to the pull cables and two passive leaflets circumferentially joined to the actuating leaflets. The actuating leaflets can be configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when the pull cables are tensioned.

[0026] The passive leaflets and actuating leaflets can be sized and shaped to guide the folding and expansion of the expandable tip. The passive leaflets can have a substantially horseshoe profile. The actuating leaflets and passive leaflets can have similar dimensions. Alternatively, the actuating leaflets can be substantially larger than the passive leaflets such that they constitute substantially larger portions of the expandable tip. In some examples, the actuating leaflets can constitute a majority of the circumference of the tip and are shaped to shorten and widen as the tip expands outward upon pull cable retraction. This motion of the actuating leaflets can help the passive leaflets to splay outward rather than just stretch between the actuating leaflets.

[0027] In another example, a thrombectomy catheter can have a tubular catheter shaft having a distal end and a catheter lumen having a longitudinal axis extending therethrough. A sliding collar can be disposed about the catheter shaft and configured to telescopically slide along the longitudinal axis. In some examples, one or more pull cables can be fixedly connected to the sliding collar and disposed about a circumference of the catheter lumen. The pull cables can be operably tensioned by a user of the catheter to slide the sliding collar along the catheter shaft.

[0028] The thrombectomy catheter can also have an expandable tip proximate the distal end of the catheter shaft. The tip can have a collapsed delivery configuration and a radially expanded deployed configuration. In some examples, the tip can have a plurality of circumferentially overlapping distal collars about the longitudinal axis. The collars can be configured to form a funnel profile when the expandable tip is in the expanded deployed configuration. In other examples, one or more outer jackets can at least partially enclose the expandable tip.

[0029] In some cases, the collar can be an extension of the braided wire support structure from the catheter shaft, such that there is no abrupt stiffness transition between the catheter body and the tip. In another example, the leaflets can be formed in a braided configuration, with adjacent leaflets woven or interwoven at a distance proximal to the distal end of the tip. In a similar example, the wire leaves of the expandable tip can be formed independent of the reinforcing wire braid of the catheter body, such that the tip and catheter shaft are separate segments. In this configuration, the proximal ends of the leaflets can be anchored in a peripheral sliding collar disposed about the catheter body.

[0030] The distal collar can be actuated in a variety of ways to expand the expandable tip. In one example, a pull cable can be directly connected to the distal peak of the collar. When the tension cable is tensioned, the overlapping collar can splay radially outward, similar to a fan. In another example, the distal collar can be connected at its proximal end to a sliding collar, such that the distal collar expands radially when the pull cable is tensioned, and the collar slides telescopically along the catheter shaft. In another example, one or more outer jackets that encase the tip collar can be connected proximally to a sliding collar, such that the collar and collar expand radially when the tension pull cable is tensioned.

[0031] For the disclosed design, the catheter shaft can have a composite construction that can include an inner layer with a low friction liner, such as PTFE, and a thick impact layer bonded to the low friction liner. The layers can be assembled as a sleeve over a mandrel that has one or more longitudinal grooves and conforms to the shape of the outer surface of the mandrel. The inner layer can take the shape of the longitudinal grooves of the mandrel, and can form a circumferential support for one or more pull wires when the guide tubes are inserted into the grooves. A coiled or braided reinforcement layer can then be disposed about the outer diameter of the inner layer. By varying the axial spacing of the coils or braid, variable stiffness properties can be provided for different axial lengths of the catheter shaft. A film cover can be applied and laminated or fused to the structure. When bonded, the mandrel can be removed to open the catheter lumen.

[0032] Other aspects and features of the present disclosure will become apparent upon examination of the following specific description. BRIEF DESCRIPTION OF DRAWINGS

[0033] The above aspects and additional aspects of the present application will be further discussed with reference to the following description and drawings, in which:

[0034] In the drawings, like numbers refer to like elements throughout the several views. The drawings, which are not necessarily to scale, depict one or more embodiment(s) of the application.

[0035] Figure 1is a view of a clot retrieval catheter with expandable tip according to aspects of the application;

[0036] Figures 2a to 2c shows an alternative example of an expandable tip according to aspects of the application connecting a pull cable to a Figure 1 ;

[0037] Figure 3 shows an alternative arrangement for changing the angle of a pull cable actuable expandable tip according to aspects of the application;

[0038] Figure 4 shows an alternative catheter example according to aspects of the application;

[0039] Figure 5 is a view of a shaft from an example according to aspects of the application; Figure 4 ;

[0040] Figure 6 shows an example of actuated leaflets from an example according to aspects of the application; Figure 4 ;

[0041] Figure 7 shows another alternative catheter example according to aspects of the application;

[0042] Figure 8 shows an expansion profile from an example according to aspects of the application; Figure 7 ;

[0043] Figures 9a to 9b shows another alternative catheter example according to aspects of the application;

[0044] Figure 10 shows a possible activation of a tip from an example according to aspects of the application; Figures 9a to 9b ;

[0045] Figures 11a to 11b depicts another alternative catheter example according to aspects of the application;

[0046] Figure 12a is an end view of a single extrudate catheter shaft configuration according to aspects of the application;

[0047] Figure 12b is an end view of a composite catheter configuration according to aspects of the application;

[0048] Figures 13a to 13d shows steps for constructing a composite catheter shaft according to aspects of the application;

[0049] Figure 14 is a cross-sectional view of a composite catheter configuration according to aspects of the application;

[0050] Figures 15a to 15b A longitudinal segment of a catheter shaft with an alternative film arrangement is shown in accordance with aspects of the present application; and

[0051] Figures 16a to 16d An example showing an alternative way of disposing a film cover on an expandable tip in accordance with aspects of the present application. DETAILED DESCRIPTION

[0052] A specific example of the present application is now described in detail with reference to the figures. Like reference numerals indicate like elements in the figures. The figures show a thrombectomy catheter with an expandable distal tip. The opening of the tip can be formed by a distal ring of a member. One or more pull cables can be retracted to actuate the distal ring of the member and expand it to a deployed state. The tip can radially expand to seal with the vessel wall, limiting flow and occluding fluid proximal to the tip, thus a more effective suction can be directed distally to dislodge and capture the clot. The catheter shaft can have a multi-lumen configuration with a central catheter lumen for passing through an accessory device and directing suction and one or more guide lumens that can guide the pull cables to the expandable tip. A flexible low modulus film can be disposed around the expandable tip and at least a portion of the catheter shaft.

[0053] It is an object of the disclosed design to form a clot retrieval catheter that can provide both local flow restriction / occlusion and a large clot-facing opening. The catheter can be highly flexible to navigate tortuous neurovascular to reach an occluded clot. The catheter can also be compatible with a relatively low profile access sheath and catheter such that a puncture wound in the patient's groin (in the case of a femoral access) can be easily and reliably closed. The clot retrieval catheter can pass through a sheath or guide with an inner diameter of less than 0.110", preferably 0.090", in some cases less than 0.087", and most preferably less than 0.085". Thus, the catheter and expandable tip can have a low delivery profile of approximately 0.084" or 2 mm, and also be able to expand its distal opening to the size of the vessel in which the clot resides, which can be as large as 5 mm. The pull cables allow the operator to control the diameter of the tip at discrete times during the procedure. The disclosed design can also allow the user to collapse the tip during or after the procedure.

[0054] Accessing various blood vessels (whether coronary, pulmonary, or cerebral) involves well-known procedural steps and the use of many conventional, commercially available accessory products. These products such as angiographic materials, rotating hemostatic valves, mechanical thrombectomy devices, and guide wires are widely used in laboratories and medical procedures. Their function and exact construction are not described in detail when used in conjunction with the systems and methods of the present invention described below. While the present description is in many cases in the context of thrombectomy treatment, these systems and methods can also be applicable to other procedures and other body passageways.

[0055] Turning to the drawings, Figure 1 A distal portion of a clot retrieval catheter 100 is shown having a proximal catheter shaft 220 and a distal expandable tip 110. The catheter 100 can be navigated to a target site in a blood vessel using standard interventional techniques and commercially available ancillary devices such as an access catheter, a balloon guide catheter, and / or a guide wire. The catheter shaft body 220 can have a generally tubular structure disposed about a longitudinal axis 111.

[0056] In one configuration, the tip 110 can have a plurality of leaflets 112, 113 that form an expandable petal shape when deployed from a collapsed delivery configuration. The leaflets can be struts or cables configured in a ring or hoop shape. Figure 1 The example shown includes two actuated leaflets 112 and two passive leaflets 113 rigidly connected to a distal end 225 of the catheter shaft 220. The two actuated leaflets 112 can be positioned 180 degrees apart and circumferentially overlapping the struts of the two passive leaflets 113.

[0057] The number of actuated and passive leaflets can vary as needed for the device. For example, increasing the number of leaflets can increase the support of the membrane and radial force for sealing with the vessel wall, but will also increase the lateral stiffness of the tip for a given strut thickness and width.

[0058] In some cases, the leaflets 112, 113 can contain a pattern that will increase flexibility, such as undulations, narrowed segments, or expandable cells. The undulations in the leaflets help the tip shorten and lengthen at opposite sides in the collapsed delivery configuration when being advanced through tortuous vessels to a target site. In addition, the undulations can help prevent one or more leaflets or portions of the tip from over-tensioning if the catheter 100 is pushed distally while the tip 110 is expanding. In other examples, the leaflets 112, 113 can have a low taper angle and bend radially inward at the distal end when expanded so that the struts do not press into the vessel wall.

[0059] The expandable tip 110 can be fixedly or flexibly coupled to the distal end 225 of the catheter shaft 220 at a proximal joint 114 and configured to radially expand from a collapsed delivery configuration within an outer sheath or catheter to a radially expanded deployed configuration. Figure 1 A fixed leaflet proximal joint 114 is shown. It will be appreciated that the leaflets can also be connected via a more flexible link, such as a grommet. The leaflets can also have features such as narrowed segments or notches that can act as uniform and consistent hinge points for the expansion and folding of the tip 110.

[0060] The catheter shaft 220 can be a multi-lumen system having a primary catheter lumen 212 and one or more guide tubes 221 that define a guide lumen 222. The catheter lumen 212 can be used to deliver ancillary devices such as microcatheters and stent retrievers and can also be used to guide aspiration distally through the expandable tip 110. The structure of the shaft 220 can be, for example, a polymer and / or metal braid support structure with an internal low-friction liner and one or more external polymer jackets that can be backflowed into the braid structure during manufacture.

[0061] The guide tubes 221 can extend axially parallel to the longitudinal axis 111 from a proximal luer interface or control handle (not shown) that is manipulated by the user. The guide tubes can terminate proximally or distally of the distal end 225 of the catheter shaft 220 or distally therefrom. The guide tubes 221 can serve as a conduit for control members or pull cables 120 that are configured to expand and / or collapse the expandable tip 110.

[0062] The outer surface of the catheter shaft 220 and expandable tip 110 can be at least partially covered by a membrane or external jacket or sleeve (not shown). The membrane or jacket can prevent proximal fluid from entering the tip during aspiration and retrieval of the clot, allowing for more effective guidance of the aspiration force while preventing migration of other clot debris distally during the procedure. In one example, the one or more jackets can be formed of a high-elasticity material such that the radial force exerted by expanding the expandable tip is sufficient to stretch the membrane to the funnel or conical profile of the tip when in the expanded deployed configuration. Alternatively, the jacket can be loose and foldable over the leaflets such that the leaflets can move freely. The loose jacket folded from the inner diameter to the outer diameter of the tip 110 can have inner and outer surfaces that are adhered or heat welded together between the leaflet struts to reduce the strain required to expand the jacket and to enhance the resistance of the inner portion of the membrane to collapse under aspiration.

[0063] Figures 2a to 2cVarious methods of flexible attachment joints between actuation leaflets 112 of expandable tip 110 and pull cables 120 are shown. Pull cables 120 can be composed of steel or a high molecular weight polymer with sufficient tensile strength to cause deflection of expansion of tip 110 when actuated by the user. Pull cables 120 help provide a smooth transition during expansion or retraction of the expandable tip and can be spaced apart circumferentially to balance passive leaflets 113 of a support tube that can not be directly coupled to catheter shaft 220. For example, by having two actuation leaflets 112 spaced 180 degrees apart, such as Figure 1 Tip 110 can bend about the bending plane of the two cables 120 when advancing to or withdrawing from a target site.

[0064] Pull cable 120 members can be secured in place with bulbous ends 118 at their distal most ends as shown in Figure 2a and Figure 2b Bulbous ends 118 can be formed during manufacturing after pull cables 120 have been fed through associated eyelets 116 formed on the expandable tip. The eyelets can be located at the proximal end of tensioning members 115 that extend proximally of the actuated tip leaflets 112. The bulbous 118 can be formed by any of a variety of methods such as knot formation, application of heat, laser cutting, molding, or by mechanical plastic deformation. In another example, eyelets 116 can be loops formed at the junction of adjacent leaflets 112.

[0065] In another example, the bulbous can have a polygonal or non-spherical shape such that they can still be held by eyelets 116 while transmitting bending moments to leaflets 112, 113 without the rigidly configured joints in all degrees of freedom. Other designs that tailor the bending stiffness of the interface between the expandable tip and the catheter body can be contemplated. Figure 2c Another design is shown that can have a flexible articulating joint where hinge links 117 are formed at the overlapping interface between pull cables 120 and tensioning members 115 of actuation leaflets 112. Hinge links 117 can be single or double pin connections that define one or more bending planes for expandable tip 110. For example, circumferentially aligned double pin connections would provide flexibility for the tip in two planes perpendicular to each other while maintaining support of the tip from all of the leaflets. The articulating joint can also be a universal joint to open up more degrees of freedom to flex tip 110.

[0066] Pull cables 120 can exit guide lumen 222 at distal end 225 of catheter shaft 220 or the shaft and guide tube 221 can have a rounded or scalloped cutout 224 formed in the outer surface of the shaft distally as shown in Figure 3The distal cutout 224 can change the pull angle imparted on the tension member 115 by the pull cable 120 by allowing a smaller exit angle from the cable lumen 222. The cutout 224 can be located a particular distance proximal to the distal end 225 of the catheter shaft 220 to fix the exit angle, as shown. In another example, the cutout can be a slot that extends a distance proximal to the distal end 225. In another example, separate pull cables 120 can be split to exit two or more distal cutouts 224 in the catheter shaft 220 in order to pull more than one actuation leaflet of the actuation leaflets 112 around the circumference to the expandable tip 110 using a single pull cable 120.

[0067] The pull cable 120 should be able to move very freely within the guide lumen 222 along the axis 111 of the catheter shaft 220. A low friction system can use materials such as PTFE or FEP for the inner lining of the guide lumen 222 and / or the outer surface of the pull cable 120. Alternatively, a lubricant such as silicone oil or molybdenum disulfide, or a coating such as a hydrophilic coating can also be used. The pull cable itself can be made of a very high modulus material so that a thin, low profile cable can be used that exhibits minimal stretch or elongation when used under tension. When the pull cable is in the form of a wire or multifilament cable, metals such as stainless steel, nitinol, or MP35N can also be used. Engineering polymers or composites such as UHMWPE, LCP, Vectran, or Kevlar can also be envisioned as suitable materials. In addition, combinations of both wire and cable and / or both metal and polymer can also be used. For example, a solid nitinol wire with a PTFE coating can be used for most of the pull cable, with a short section of UHMWPE near the distal end that helps to connect the pull cable to the actuation leaflets 112 of the expandable tip 110. If desired, a proximal solid monofilament can also be used to provide good pushability and column stiffness in the pull cable so that it can be advanced to collapse the frame.

[0068] In Figure 4 In another configuration shown, the catheter 100 can have a tubular catheter shaft 220 configured around a longitudinal axis 111. The catheter shaft 220 can have longitudinal and / or transverse cutouts 228 machined into the surface at regular or variable spacing so that the flexibility of the catheter 100 can be tailored along its length. For example, the size or spacing of the slots can be set to impart greater pushability and trackability characteristics to the proximal portion of the catheter. Different slot spacing along the more distal length of the shaft 220 can provide greater flexibility for the tortuous and winding vessels near an occlusive clot.

[0069] The illustrated catheter shaft 220 may have two guide tubes 221 spaced 180 degrees apart on opposite sides of the shaft circumference. The guide tubes 221 may be used to guide the traction cable 120 for actuating the expansion and collapse of the distal expandable end 110. The guide tubes 221 may extend the entire length of the catheter shaft and circumferentially interrupt transverse cuts or slots 228 in the shaft to form a longitudinally extending ridge 230. The axial ridge 230 may have a constant thickness or may be tapered to provide a smooth, rigid transition between the proximal and distal portions of the catheter shaft 220.

[0070] exist Figures 4 to 6 In the example shown, the expandable end 110 has six strut segments that form a leaflet 124 with six distal peaks 119. The leaflet 124 can be integrally laser-cut with the polymer catheter shaft 220, and can be processed into individual components (such as...). Figures 4 to 6 (As seen), or processed into a combination of integral and individual components. Adjacent leaflets 124 may circumferentially overlap at intersection 126. The leaflets do not need to be fixedly connected at the intersection, allowing them to interweave and slide and fold relative to each other as the ends 110 expand or contract. Designs with more than six leaflets are conceivable, where additional leaflet struts sacrifice some end flexibility while providing additional radial force and support to prevent collapse of the jacket or membrane (not shown). Similarly, fewer leaflets can be used where membranes with greater stiffness or thickness require less support.

[0071] One or more pull cables 120 may extend along the length of shaft 220 within the guide cavity 222 of guide tube 221. The pull cables 120 may form a distal loop 122 configured to surround an overlap 126 of two adjacent leaflets 122. When tensioned, the pull cables 120 may be pulled outwards towards the overlap 126 to increase the radial dimension and deploy an expandable end 110. In some cases, the guide tube 221 of shaft 220 may have a distal extension 227 extending beyond the distal end 225 of shaft 220.

[0072] Figure 5 It shows Figure 4 The catheter shaft 220 of the catheter 100. An anchoring slot 226 can be positioned near the distal end 225 of the shaft 220 to provide rigidity and retention for the proximal connector 114 between the shaft and the leaflets 124 of the distal end 110. Individual adjacent leaflets 124, such as... Figure 6The illustrated example can have a collar shape with a distal peak 119 and proximal feet or anchors 128. The leaflets 124 can be interwoven and their proximal leaflet anchors 128 laser welded or bonded together within anchor slots 226 of the shaft 220. In another example, some of the leaflets can be formed integrally with the shaft, while other leaflets have anchors 128 welded or adhered to the shaft. As another alternative, a collar around the distal end 225 of the shaft 220 can serve as a retention ring to control axial motion of the leaflet anchors 128 (examples of which are shown in Figure 9a

[0073] A distal portion of another example of a thrombectomy catheter according to aspects of the present disclosure is shown in Figure 7 The tubular catheter shaft 220 can be formed of a polymer extrusion. The extrusion can be made, for example, of polyether ether ketone (PEEK) or another rough thermoplastic polymer. The extrusion can be configured to have axial and / or transverse slots 228 cut into the outer surface to impart additional lateral flexibility to the tubular shaft 220. The cutouts can be longitudinally aligned or offset to tailor the stiffness characteristics of different axial segments of the shaft 220. The slots 228 can be circumferentially discontinuous so as to form one or more longitudinal ridges 230 along the length of the shaft 220.

[0074] One or more pull cable guide tubes 221 can be disposed around the circumference of the catheter body 220 and can extend the length of the catheter axis. The tubes 221 can be tangential and flush with the outer surface of the catheter tube, or can be mid-wall or some other arrangement. As shown, some examples can have two pull cables spaced 180 degrees around the circumference of the catheter shaft, although other spacing arrangements can be contemplated when a greater number of cables are used. The guide tubes 221 can or can not be radially aligned with the one or more longitudinal ridges 230, such that these tubes can serve as additional stiffness features if desired. Each guide tube can have an internal tubular lumen 212 sized to allow free relative axial motion of the pull cable 120. Similar to other designs, a distal cutout 224 can be provided to allow the pull cable 120 to radially flex when tension is applied. The guide tubes can be robust polymer tubes that provide good column stiffness and resistance to kinking, such as polyimide tubes.

[0075] ​The funnel design of the expandable tip 110 in this example can be an integral mesh of leaflets 240, 241 directly laser-cut from the catheter shaft 220. Alternatively, the expandable tip 110 mesh can be injection-molded as a single piece and attached to the shaft 220 by thermal welding, adhesive, or similar methods. The actuated leaflets 240 can be operatively coupled to the traction cable 120 in a configuration similar to those previously described (such as knots, loops, or eyelets). Leaflets 240, 241 can be rounded distally and have a slightly inclined ring or petal shape for non-invasive contact with the vessel wall during dilation. Leaflets 240, 241 can include bends such that the leaflets can shorten and widen as the tip 110 expands outward when the traction cable 120 retracts. As in other examples, a polymer jacket or membrane can cover or encapsulate at least a portion of the tip 110 and the catheter shaft 220.

[0076] Figure 7 An expandable end 110 in a collapsed delivery configuration is shown. The end 110 may include two actuating leaflets 240 and two passive leaflets 241 rigidly connected to the distal end 225 of the catheter shaft 220. The two passive leaflets 241 may circumferentially engage with the actuating leaflets 240 at a circumferential joint 229, and the actuating leaflets may be fixedly connected to one of the traction cables.

[0077] The actuated leaflet 240 can occupy a significantly larger portion of the circumference of the expandable distal end 110 than the passive leaflet 241. For example... Figure 7 As shown, the passive leaflet 241 may have a generally horseshoe-shaped profile, wherein the horseshoe-shaped legs are circumferentially compressed together when the end 110 is in a collapsed delivery configuration. The shape of the actuating leaflets 240 can be adjusted such that they shorten and widen (and flare outward) when the pull cable 120 retracts. This shape will help adjacent passive leaflets 241 to open when pulled at the circumferential joint 229, thus forming a more rounded funnel rather than being simply stretched into an oval funnel shape.

[0078] Figure 7 Shown in expanded deployment configuration Figure 8 In the middle. The passive leaflet 241 may be shorter and intersects at the circumferential junction 229 along the length of the actuating leaflet 240, such that the passive leaflet opens to a larger radial dimension. The combined opening of all leaflets helps to form a more rounded, more uniform funnel, which is better shaped to seal with the blood vessel and to receive and compress the captured clot once it has been removed. In the example shown, the membrane or clip 430 may be trimmed to conform to the profile of the expanded opening at the end 110. In other examples, the clip 430 may follow a square or non-invasive concave profile.

[0079] Figure 9a and Figure 9bAnother configuration of the funnel-shaped catheter tip 300 is shown, in which the leaflets are formed from a braided or loop-woven structure 310. The wires of the leaflets can form an overlapping distal collar 312 that can be interwoven and secured in a sliding collar 320 that can slide telescopically along the catheter's axis 111. The catheter body 220 can also have a woven or braided support structure that can form a tubular shape about the longitudinal axis 111. The density of the woven mesh can be configured so as to tailor the local stiffness characteristics for axial segments of the catheter shaft 220. The distal collar 312 can be integral with the wire braid 310 of the catheter, and the wire length and / or braid angle can be tailored so that when expanded, as shown, the collar forms a soft funnel profile for the expanded tip 300. Figure 9b

[0080] In examples in which the braided structure 310 of the expandable tip 110 and the catheter shaft 220 can be integrally formed, pull wires (not shown) can be looped about the braid intersections 314 for expanding the tip 110 to the deployed configuration. In another example, the wires of the distal collar can extend proximally to have a proximal junction 114 that is either directly secured to the catheter body 220 or embedded within an outer polymer jacket 430. The braid intersections 314 of the distal collar 312 can be kept as distal as possible. The distal collar 312 can be free to move and slide relative to one another.

[0081] The braided mesh can have a wire construction and can utilize an alloy with shape memory properties, such as Nitinol. To form the braided mesh, the integral wire can be wrapped around a shaped tool with a tapered bullet-shaped nose to heat set the tip to a decreasing outer diameter distally for atraumatic crossing within a blood vessel. To impart increased stiffness to the wire to aid in opening the elastomeric membrane, the wire outer diameter can be relatively large. In one example, the wire outer diameter can be in the range of 0.004" to 0.008". To maximize the flow velocity and proximal cross section of the tip for receiving a clot, a segment of the wire can be flattened with a press tool. The distal segment of the wire forming the expandable tip that opens upon actuation can also be flattened, but this segment can also be round as the increased diameter of the tip in the expanded deployed state will not affect the cross section.

[0082] Figure 10 Another configuration of the funnel-shaped catheter tip 300 is shown, in which the leaflets are formed from a braided or loop-woven structure 310. The wires of the leaflets can form an overlapping distal collar 312 that can be interwoven and secured in a sliding collar 320 that can slide telescopically along the catheter's axis 111. The catheter body 220 can also have a woven or braided support structure that can form a tubular shape about the longitudinal axis 111. The density of the woven mesh can be configured so as to tailor the local stiffness characteristics for axial segments of the catheter shaft 220. The distal collar 312 can be integral with the wire braid 310 of the catheter, and the wire length and / or braid angle can be tailored so that when expanded, as shown, the collar forms a soft funnel profile for the expanded tip 300. Figure 9a ​An example of the illustrated tip example actuation mechanism in its deployed configuration. A collar 320 can be slidably disposed about at least a portion of the catheter shaft 220 and configured to translate along the longitudinal axis 111 of the catheter by tensioning or pushing one or more pull cables 120. The distal collar 312 can have a collar tensioning member 322 connected to the sliding collar 320. The tensioning member 322 can be a wire or a strip and can be connected to some or all of the collars 312 of the braided structure 310 of the expandable tip 300. The tensioning member 322 can then open and expand the tip when the collar 320 is pulled proximally with the pull cable 120. The strands of the distal collar 312 can be embedded or otherwise connected to the shaft 220 such that they expand radially when the collar is translated proximally. The pulling force can be distributed evenly across the collar 312 by two pull cables 120 spaced 180 degrees apart.

[0083] Alternatively, at least a portion of the outer jacket or membrane 430 can be inverted over the expandable tip 110 and bonded to the slidable collar 320. The membrane 430 can extend radially inward from the collar 312 to bond to the inner diameter of the shaft 220. The membrane 430 can then radially expand the collar 312 when the collar 320 is pulled proximally with the pull cable 120.

[0084] It should be noted that any of the catheter designs disclosed herein can also be used with one or more stentrievers. The combination of stentriever retraction and effective suction through the enlarged tip segment in the expanded deployed configuration can work together to increase the likelihood of first pass success in removing the clot. The catheter can also direct the suction vacuum to the clot face while the stentriever holds the composite clot (consisting of friable areas and fibrin-rich areas) together, preventing embolization and helping to move the clot away from the vessel wall. The funnel-shaped tip segment can also reduce clot shearing upon entry into the catheter and block flow to protect the distal vessel from new area embolization.

[0085] Figure 11a and Figure 11bAn additional configuration of the funnel-shaped catheter tip 300 is shown, wherein the leaflets are formed by a braided or coiled weave structure 310. The braided structure 310 of the tip 300 may be integral with the braided structure of the catheter shaft 220. The pattern of the braid 310 allows actuation of the tip from two pull wires 120 to transfer force from the diametrically opposed actuated leaflets 340 to adjacent passive leaflets 341, such that all leaflets move from a substantially tubular, collapsed delivery state as shown to an open deployment configuration for suction and / or delivery devices. In one example, the pull wires 120 may be attached to a braided loop or eyelet 316 at the distal end 325 of the actuated leaflet 340. In another example, the pull wires 120 may simply be welded to the middle of the distal end 325 of the actuated leaflet 340 or attached at the braided intersection 314.

[0086] like Figure 11a As shown, the actuating leaflet 340 can be positioned below (radially inward) each of the adjacent passive leaflets 341, such that the tensioning pull wire (not shown) can open all leaflets in a balanced manner. Proximal to the actuating leaflets 340, 341, the struts can each have a single twist at the cross-leaf twist point 342, which helps to anchor the leaflets relative to each other and serves as a pivot for the radial expansion of the end 300. Alternatively, spot welding between the leaflets at the twist point 342 can secure this position. An advantage of this configuration is that the connection between the pull wire and the actuating leaflets does not need to be slidable when the expandable end is open, because the leaflets 340, 341 can slide relative to each other at the cross-point 314.

[0087] In another configuration, the traction wire 120 at the distal end 300 can form a loop above the distal leaflet crossing point 314, similar to... Figure 4 The expandable end is shown in the diagram. This configuration allows for a more uniform translation of tension in the traction wire to the expanding leaflet. In this configuration, the actuating leaflet 340 can be positioned above (radially outward) or below (radially inward) the adjacent passive leaflet 341. However, the traction wire attachment at the crossover point 314 must be slidable to allow the crossover point to slide to a more proximal position as the leaflet expands radially.

[0088] The woven fabric 310 may be covered with a membrane or an outer jacket 430, such as Figure 11b As shown. The jacket 430 extends distally from the inner diameter of the catheter below the leaflets 340, 341 at the distal end 300, and is inverted at the distal end 325 to extend proximally above the leaflets. Since the inverted jacket 430 does not need to be adhered to the distal end with this design, the leaflets can move freely relative to each other within the inverted jacket.

[0089] Similar to the previous example, the pull cable guide tube 221 can extend longitudinally with the catheter shaft 220. In some examples, the pull cable 120 can extend distally from the guide tube under the woven leaflets 340, 341. This orientation will make the catheter easier to assemble at the cost of reducing the leverage for actuating the tip 300, as the point of torsion 342 can limit the radial movement of the pull cable 120 when the tip expands. In other examples, the leverage for actuated expansion of the tip can be maintained by threading the pull cable 120 onto the leaflets 340, 341 so that there is no restriction when the pull cable exits the guide tube 221. This configuration can allow for higher opening force to be generated, but the assembly of the catheter can be more difficult compared to when the pull cable is threaded under the leaflets.

[0090] Various manufacturing methods can be employed to make the example catheters disclosed herein. Figures 12a to 12b A transverse end view of a possible method of construction of the catheter shaft 220 of a clot retrieval catheter is shown. In Figure 12a The shaft can be a single piece multi-lumen extrusion that is then laser cut to increase flexibility. For example, the shaft 220 can have a helical cut segment between the proximal end and the distal end. The cut can include a variation in cut width such that a longitudinally aligned series of narrow transverse slots can form one or more axial ridges 230 parallel to the guide tubes 221 in the extrusion. The axial ridges can impart good pushability to the shaft while maintaining flexibility of the shaft. The multi-lumen shaft 220 can have dual guide tubes 221 with pull cable lumens 222 spaced 180 degrees apart. At least one of the dual pull cable lumens 222 can also have an internal tether (not shown) extending therethrough to prevent over-elongation of the shaft under tension. In one example, the tether or tethers can be made of a fluoropolymer or other material that imparts resistance to stretching. The limited stretch allows the cut in the extrusion to open when the shaft 220 is in a small radius in the vessel. The tether can also resist the cut from substantially pulling apart under more significant tension, such as in the case of the expandable tip needing to retract into an outer sheath or intermediate catheter when a rigid fibrin-rich clot mass is gathered in the tip.

[0091] In one example, the catheter can have a shaft having an inner surface and an outer surface, where the circumference of the inner surface is greater than the circumference of the outer surface. Although shown as being tangent to and traversing the inner wall of the extrusion, it should be understood that the pull cable guide tube 221 and lumen 222 can also be located outside of the medial wall or the outer wall of the extrusion.

[0092] The extrusion can be a high modulus thermoplastic polymer such as PEEK, polyamide (Pa) or nylon such as TR55 to impart excellent pushability to the shaft. Additionally, the extruded material can be a high modulus and low friction polymer to facilitate passage of other devices of the procedure such as microcatheters, stent retrievers and guidewires. A heat shrinkable outer jacket or film 430 (not shown) can seal the shaft 220 extrusion as it is fused to the outer diameter of the shaft.

[0093] In another example, a low friction layer or low friction film can be applied to the inner diameter of the shaft 220 by using a small size PTFE or other low friction liner with an external impact layer for bonding, which can be positioned inside the extrusion. A heated mandrel with an enlarged end can then be pulled through the liner to expand the liner and adhere it to the inner surface of the laser cut extrusion. Additional heat can be applied to the extrusion as necessary to fuse the inner liner.

[0094] Figure 12b An alternative shaft 220 is shown with a layered composite construction. These layers can include a low friction inner sleeve or liner 410 and a tubular core 420, to which an outer jacket or film 430 can be applied. The core can be an extrusion, a laser cut hypotube or a coiled or braided mesh to provide structure and reinforcement to the catheter shaft 220.

[0095] The composite layered catheter shaft 220 can be described by a construction method as shown in Figures 13a to 13d In Figure 13a a substantially cylindrical mandrel 400 can be fabricated that can have an outer diameter approximately the same as the desired inner diameter of the catheter shaft 220. The mandrel 400 can have one or more longitudinal lumen grooves 402 machined into the outer surface parallel to the longitudinal axis 111 to serve as a mold for the pull wire guide tube 221.

[0096] In Figure 13b the composite construction can include a flexible inner layer 410 with a low friction liner 411 (e.g. PTFE or PET) and a thick impact layer 412 bonded to the low friction liner. The flexible inner layer 410 can be assembled as a sleeve over a cylindrical mandrel 400. In Figure 13cIn some embodiments, a polyamide or similar tube forming a lumen guide tube 221 can be inserted into the lumen channel 402 of the mandrel 400 to press the inner layer 410 into the channel. Then, a coil or braid reinforcement layer 420 can be wrapped or disposed around the outer diameter of the inner layer 410 and the guide tube 221. As previously described, the pitch or axial spacing of the coil or braid reinforcement layer 420 can be varied to tailor the stiffness characteristics for different axial lengths of the catheter shaft 220. The reinforcing coil 420 can securely tie the guide tube 221 to the inner layer 410. In other examples, a laser cut tube can be used in place of the coil or braid and slid over the assembly to hold the mandrel 400, inner layer 410, and guide tube 221 together.

[0097] As used herein, the terms jacket, film, and cover are used interchangeably. An outer jacket or film 430 can be applied on top of the composite construction and reflowed or laminated using heat shrink to hold the assembly together. In some cases, the jacket can be several segments with different material properties. In some cases, the jacket can be a single segment of material. Figure 13d In some embodiments, once the jacket or film 430 is secured, the channel-like mandrel 400 can be removed.

[0098] Figure 14 The composite catheter shaft 220 construction that can be produced by the method of Figures 13a to 13d A cross-sectional view of a composite catheter shaft 220 construction that can be produced by the method of

[0099] Suitable jacket materials can include elastomeric polyurethane, such as neoprene that can have a Shore hardness of 40A or lower, or a silicone elastomer. If the catheter shaft 220 and tip frame are formed from polymeric extrusions, spaces, slots, or patterns can be laser cut into the outer surface and the jacket can be reflowed or injection molded into the spaces during manufacture. Alternatively, the jacket can be laminated onto the structure.

[0100] To allow smooth delivery of the clot retrieval catheter 100 through an outer catheter, the outer surface of the film 430 can be coated with a low-friction or lubricious material, such as PTFE or a commercially available lubricious coating, such as those provided by Surmodics, Harland, Biocoat, or Covalon. Similarly, the inner surface of the catheter shaft 220 can also be coated with the same or similar low-friction material for aiding passage of the device and facilitating pulling of the captured clot proximally through the catheter 100 with suction and / or mechanical thrombectomy devices.

[0101] In other examples, the jacket or film can be a direct extrusion or an extrusion that is post-formed onto the expandable tip and catheter body. Alternatively, where the catheter shaft and expandable tip have laser cut struts, coils, or braided structures, the structures can be encapsulated within a film as part of a dip coating or plasma deposition process.

[0102] The cover can be trimmed to follow the profile of the opening of the expandable tip along the perimeter of the opening, or the cover can be trimmed to have a flat. In another example, the cover film can be folded radially inboard and proximal of the distal peak of the leaflets and heat welded between the inner and outer layers. The thickness of the cover can be maintained between and over the leaflets of the tip, or it can be machined to have a uniform thickness.

[0103] Alternatively, the jacket or film 430 can also be formed from a series of polymeric jacket layers 238, as shown in FIG. 23. For example, the polymeric jackets 238 of the cover can be disposed in a radial series around the catheter shaft 220 to tailor material properties throughout the thickness, as shown in FIG. 24. Alternatively, jackets or sets of jackets 238 of different hardness can be disposed in discrete lengths along the axis around the catheter shaft 220 to provide different pushability and flexibility properties to different segments of the catheter, as shown in FIG. 25. By configuring the jackets in series axially, the overall stiffness of the catheter can be transitioned from a relatively hard proximal end to a very flexible distal end. Figures 15a to 15b Figure 15a Alternatively, jackets or sets of jackets 238 of different hardness can be disposed in discrete lengths along the axis around the catheter shaft 220 to provide different pushability and flexibility properties to different segments of the catheter, as shown in FIG. 25. By configuring the jackets in series axially, the overall stiffness of the catheter can be transitioned from a relatively hard proximal end to a very flexible distal end. Figure 15b

[0104] The series of polymeric jackets 238 can be butted together and fused to the catheter shaft 220. The expandable tip can have the same or separate jacket or jackets that can be dip coated and can abut or be under or over the jacket or jackets of the catheter shaft. If the jacket of the tip is under the jacket of the shaft, the jacket can be made of a material that can withstand the heat generated when the jacket of the support tube is reflowed. In another example, a pre-formed outer jacket with variable stiffness and elastic properties can replace the series of polymeric jackets.

[0105] Figures 16a to 16d A number of examples are briefly shown of how the jacket 430 can be disposed around the unexpanded tip 110 toward the distal end of the catheter shaft 220. Figures 16a to 16b ​​An example is shown in which the jacket 430 has been applied with a crease or fold 432 to allow folding in the event of an oversized or sagging jacket to achieve a thin profile delivery state. The fold 432 can then unfold as the tip 110 expands into a deployed configuration. The jacket 430 can overlap the expanding petals or lobes of the tip to extend the circumference and minimize strain placed on the jacket as the tip expands. In a similar example, the jacket 430 can be only slightly oversized for the expandable tip, and the combination of unfolding the fold 432 and elastic expansion of the jacket serves to conform the jacket to the profile of the expanding tip.

[0106] Figure 16c A profile cross-sectional view of a distal portion of the catheter 100 is shown in which a cover film 430 is applied over the expandable tip 110. The film 430 can be impregnated or deposited with a plasma process and subsequently laminated to the frame. The film edges can be trimmed to follow the distal edge of the tip 110 or remain as a flat plane. In the example shown, the film 430 is applied over the frame of the tip 110 and is trimmed to follow the distal edge of the tip 110. Figure 16d In the example shown, the film 430 can be allowed to fold or invert around the frame of the tip 110 such that a soft, atraumatic lip 434 is formed. The film 430 can be fused to the tip 110 or the tip structure can be configured to slide freely within the lip 434.

[0107] The present invention is not necessarily limited to the examples described, which can vary in configuration and detail. The terms "distal" and "proximal" are used throughout the preceding description and refer to position and direction relative to the position of the treating physician. Likewise, "distal" or "distally" refers to a position away from or in a direction away from the physician. Similarly, "proximal" or "proximally" refers to a position near or in a direction toward the physician. Furthermore, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0108] As used herein, the term "about" or "approximately" with reference to any numerical or range of numbers indicates suitable dimensional tolerances that allow the components or elements to function as intended as described herein. More specifically, "about" or "approximately" can refer to a range of values ±20% of the recited value, for example "about 90%" can refer to a range of values from 71% to 99%.

[0109] In describing example embodiments, terminology will be resorted to, so as to be clear in the specification and claims. Such terminology is used in the descriptive sense only, and not for purposes of limitation. Each term is intended to encompass its broadly understood meaning, as well as its specifically known meanings, and is intended to include all technical equivalents that operate in a similar manner to accomplish a similar purpose. It should also be understood that a recitation of one or more steps of a method does not preclude the presence of additional method steps or intervening method steps between those explicitly identified. Some steps of a method can be performed in a different order than described herein without departing from the scope of the disclosed technology. Similarly, it should also be understood that a recitation of one or more components in an apparatus or system does not preclude the presence of additional components or intervening components between those explicitly identified. For the sake of clarity and conciseness, not all possible combinations are listed, and such modifications are generally apparent to those skilled in the art and are intended to be within the scope of the claims.

Claims

1. A thrombectomy catheter, the catheter comprising: a tubular catheter shaft, the tubular catheter shaft comprising: a distal end and a catheter lumen having a longitudinal axis extending therethrough; one or more pull wire guide tubes comprising a pull wire lumen disposed about a circumference of the catheter lumen and extending a longitudinal length of the catheter shaft; and one or more pull wires disposed within the pull wire lumen and operably tensionable by a user of the catheter; an expandable tip having a collapsed delivery configuration and a radially expanded deployed configuration, the tip comprising one or more leaflets disposed about the longitudinal axis and configured to assume a funnel profile when the expandable tip is in the expanded deployed configuration; wherein the one or more pull wires are configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when tension is applied to the pull wires, wherein the plurality of leaflets comprise one or more actuated leaflets and one or more passive leaflets, wherein the one or more actuated leaflets and one or more passive leaflets comprise an annular strut comprising a distal peak and one or more proximal joints connected to the catheter shaft, wherein each of the one or more actuated leaflets further comprises a tensioning member extending proximally from the distal peak of the leaflet and fixedly connected to a pull wire, and wherein the pull wire comprises a bulb connected to an eyelet of the tensioning member.

2. The catheter of claim 1, the actuated leaflets and the passive leaflets configured to slide over one another as the expandable tip transitions between the collapsed delivery configuration and the radially expanded deployed configuration.

3. The catheter of claim 1, the catheter shaft further comprising one or more distal cutouts from the pull wire guide tubes proximate the distal end, the distal cutouts configured to allow the pull wires to exit the pull wire lumens at a small angle relative to the longitudinal axis.

4. The catheter of claim 1, the pull wires comprising a distal loop configured to loop about the annular strut of the one or more actuated leaflets.

5. The catheter of claim 1, the proximal joints of the leaflets comprising leaflet anchors configured to engage with a plurality of anchor slots proximate the distal end of the catheter shaft.

6. The catheter of claim 1, the pull wire guide tubes further extending a distance distally of the distal end of the catheter shaft.

7. The catheter of claim 1, the expandable tip at least partially enclosed by one or more outer jackets.

8. A thrombectomy catheter, the catheter comprising: a tubular catheter shaft, the tubular catheter shaft comprising: a distal end and a catheter lumen having a longitudinal axis extending therethrough; one or more pull cable guide tubes disposed about a circumference of the catheter lumen, the guide tubes having one or more pull cables disposed within a pull cable lumen and operably tensionable by a user of the catheter; and an expandable tip integrally formed at a distal end of the catheter shaft, the expandable tip including a plurality of leaflets configured to radially expand from a collapsed delivery configuration to an expanded deployed configuration when the one or more pull cables are tensioned, wherein the plurality of leaflets includes one or more actuation leaflets and one or more passive leaflets, wherein the one or more actuation leaflets and one or more passive leaflets include a ring strut including a distal peak and one or more proximal joints connected to the catheter shaft, wherein each of the one or more actuation leaflets further includes a tensioning member extending proximally from a distal peak of the leaflet and fixedly connected to a pull cable, and wherein the pull cable includes a bulb connected to an eyelet of the tensioning member.

9. The catheter of claim 8, the expandable tip at least partially enclosed by one or more outer jackets.

10. The catheter of claim 8, the one or more pull cables including two pull cables spaced 180 degrees about a circumference of the catheter shaft.

11. The catheter of claim 10, the plurality of leaflets including two actuation leaflets and two passive leaflets circumferentially joined to the actuation leaflets, each of the actuation leaflets fixedly connected to one of the two pull cables; the actuation leaflets configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when the pull cables are tensioned.

12. The catheter of claim 11, the passive leaflets including a substantially horseshoe profile.

13. The catheter of claim 11, the actuation leaflets including a substantially greater portion of an expandable tip circumference than the passive leaflets.

Images