Actuated expandable oral thrombectomy catheter

Abstract

To provide a clot retrieval catheter.SOLUTION: A clot retrieval catheter 100 can have an expansile distal tip 110 for flow restriction / arrest and improved aspiration efficiency, and a large, distally facing mouth into which clots or other obstructions can be retrieved. The tip can be formed from leaflets 112, 113. One or more pull cables 120 can be retracted to actuate and radially expand the distal tip. The clot retrieval catheter can have a catheter shaft 220 with flexibility-adding features proximal to the tip. The catheter shaft can have a multi-lumen configuration with a large catheter lumen 212 for directing aspiration and one or more guide lumens 222 which can route the pull cables to the leaflets of the expansile tip. A flexible, low-modulus membrane can be disposed around at least a portion of the expansile tip and catheter shaft.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 941,585, filed November 27, 2019, which is incorporated by reference in its entirety.

[0002] FIELD OF THEINVENTION The present invention relates generally to devices and methods for removing an acute occlusion from a blood vessel during an intravascular medical procedure, and more particularly, to a retrieval catheter having an expandable tip capable of retrieving an object. [Background technology]

[0003] Clot retrieval catheters and devices are often used for mechanical thrombectomy for endovascular interventions when patients suffer from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Access to neurovascular beds is particularly challenging with conventional techniques because the target vessels are small in diameter, remote to the insertion site, and highly tortuous. Conventional devices are often either too large in profile and lack the deliverability and flexibility required to navigate tortuous vessels, or are ineffective at removing clots when delivered to the target site.

[0004] The clot itself can complicate treatment by assuming a number of complex morphologies and consistencies, ranging from simple tubular structures taking the shape of a blood vessel to long strand-like arrangements that can span multiple blood vessels at once. The age of a clot can also affect its compliance, with older clots tending to be less compressible than fresh clots. Experience has also demonstrated that the mechanical properties of the clot can be influenced in significant ways, depending on the nature of the interaction with the clot retrieval device. Furthermore, several mechanisms serve to strongly attach the clot to the vessel wall. Breaking these bonds without damaging the fragile blood vessels is a significant challenge.

[0005] Effective device delivery to the small, highly branched cerebral arterial system remains challenging, and conventional clot retrieval catheters suffer from 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 be flexible enough to navigate the vasculature and withstand high strains while also possessing axial stiffness to provide smooth advancement along the pathway. Once at the target site, typical objects retrieved from the body are substantially larger in size than the catheter tip diameter, making retrieval of the object into the tip more difficult. For example, fibrin-rich, tough clots can often be difficult to extract because they can become lodged in the tip of a conventional fixed-port catheter. In addition, this lodging can cause otherwise soft portions of the clot to be sheared off from the tough region.

[0006] The small diameter and fixed tip size are also inefficient in inducing the suction required for the removal of blood and thrombus material during the procedure. The suction must be strong enough so that any debris that may result from the use of suction or mechanical thrombus removal devices cannot dislodge and occlude the distal vessel. However, when aspirating with a fixed port catheter, a significant portion of the aspirate flow will come from the vascular fluid proximal to the tip of the catheter where no clot is present. This significantly reduces the efficiency of aspiration and reduces the success rate of clot removal.

[0007] Therefore, many catheter designs have a port that can be expanded at the target site. Once the clot is captured and drawn proximally into the funnel-shaped tip, it can be gradually compressed during retrieval and aspirated through the catheter to be loaded into an aspiration syringe or canister. Additionally, if the clot becomes lodged within the funnel-shaped tip, the expanded port can protect the clot and maintain aspiration to prevent it from dislodging as the catheter is retracted into the guide catheter or outer sheath. Summary of the Invention [Problem to be solved by the invention]

[0008] However, any catheter design attempting to overcome the above design challenges with an expanding distal tip or funnel structure would need to have the strength to grip the clot and apply a consistent radial force in the expanded state. The structure would also need to be flexible and resilient when in the collapsed state to withstand the severe mechanical strains imposed when navigating tortuous vasculature. The tip would also need a means for the user to actuate the expansion in a consistent and repeatable manner when deployed from an access or intermediate catheter, balloon guide catheter, or other such sheath.

[0009] The present design aims to provide an improved retrieval catheter with an expandable tip that incorporates these features to address the deficiencies noted above. [Means for solving the problem]

[0010] The design herein may be a clot retrieval catheter capable of providing localized flow restriction / stoppage within the target vessel while also having a large mouth facing the clot. The catheter may be sufficiently flexible to allow for navigating highly tortuous areas of the anatomy, such as the neurovasculature, to reach the occlusive clot. The catheter may also be compatible with relatively low profile access sheaths and catheters for deliberate advantage.

[0011] The clot retrieval catheter may have a substantially tubular body with one or more internal lumens extending therethrough. A large central catheter lumen may be configured for passage of guidewires, microcatheters, stent retrieval devices, and other such devices therethrough. The lumens may also direct suction to an expandable tip at the distal end of the catheter. The tubular body may terminate at a distal end where the expandable tip may be integrally formed or fixedly connected. The tip may be configured to expand from a collapsed delivery configuration to an expanded deployed configuration when extended from an access catheter or intermediate catheter at the site of an occlusive thrombus. Expansion may be activated by the user with a control on the proximal handle of the catheter.

[0012] In some examples, the tubular body can have a series of looped ribs extending laterally at various lengths from one or more axially extending longitudinal spines. The ribs and spines can be monolithically formed by laser machining or extrusion of a polymer tube. In another example, the tubular body can be a metallic braided or coiled wire structure coated with or contained within a polymer jacket. The spine can be fixedly connected to or integrally formed with a portion of the expandable tip.

[0013] 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 a control member, such as a tension cable, which may be tensioned or pushed by the user and can be distally connected to one or more members of the expandable tip. The tension wire can be constructed of steel or highly elastic polymer with sufficient axial stiffness so that both tensioning and pushing of the wire actuates the tip function. One or more tension cable guide tubes can be disposed around the circumference of the catheter body and can extend the length of the catheter shaft. Each guide tube can have an internal tubular lumen sized to allow unhindered relative movement of the tension cable. The tension wire guide tube can abut either the inner or outer wall of the support tube, or the tension wire guide tube can form an intermediate wall.

[0014] In some instances, the guide tube can terminate at a point proximal to the distal end of the tubular catheter shaft and can be flush with the distal end of the shaft or extend a further distance distal to the distal shaft. A distal notch can also be machined or formed proximal to the distal end of the catheter shaft and / or guide tube to allow for a more gradual, shallower expansion angle of the tensioning cable relative to the longitudinal axis. A proximal control handle or luer can allow the tensioning cables to be tensioned together, which can provide a uniform and consistent radial expansion around the circumference of the expandable tip.

[0015] In the expanded deployed configuration, the tip can assume a substantially conical or funnel shape with the struts forming multiple lobes or distal hoops about the longitudinal axis, thereby defining a distally facing open mouth for retrieval of occlusion material. The lobes can have distal peaks with gently sloping loops or petal shapes for atraumatic contact with the vessel wall upon expansion. The lobes can also overlap each other circumferentially such that adjacent lobes are capable of relative sliding motion relative to each other. This configuration can provide enhanced flexibility to the tip by allowing twisting or bending motion in tortuous regions of the vasculature. The overlapping lobes can also allow the tip to fold over on itself for low profile delivery capabilities and when the tip is folded back into the outer sheath or catheter. The lobes may or may not be axially symmetric with the longitudinal axis of the catheter. The struts forming the lobes can be connected at a distal end of the tubular body, and the struts may be aligned with one of one or more axial spines of the support tube.

[0016] In some examples, the multiple lobes can include one or more actuating lobes and one or more passive lobes. The actuating lobes and the passive lobes can have distal peaks and one or more proximal junctions connected to the catheter shaft. Each of the one or more actuating lobes can be connected to a tension cable for actuating and expanding the expandable tip.

[0017] The connection between the pull wires and the lobes can have a variety of configurations so that the tip maintains some lateral flexibility at the junction. The pull wires can be connected to the lobes through a number of means. In one configuration, one or more tensioning members extend proximally from the distal peaks of the actuation lobes and terminate within the eyelet. The pull cable extending distally from the guide tube of the catheter body can terminate in an enlarged bulb at its distal-most end that extends through the eyelet so that the pull cable and the lobe struts are linked but not rigidly connected. When bent or when the tip is placed under a compressive load during clot retrieval, the less rigid connection can give the tip more flexibility and the ability to deflect locally for a tighter grip on the captured clot.

[0018] In other examples, the bulb can have a polygonal or non-spherical shape, as other designs can be envisioned that tailor the bending stiffness of the interface between the expandable tip and the catheter body. Further designs can have flexible hinged joints, such as pin connections between the lobe struts and tension cables that extend distally from the guide tube of the catheter body. The hinged joints can define or bias a particular bending plane of the catheter during delivery.

[0019] In some examples, at least a portion of the lobes can include patterns that increase flexibility, such as undulations or expandable cells, etc. In one example, the lobe struts can have a wavy shape or have narrowed sections to improve the overall flexible tip structure.

[0020] The proximal joints of the lobes can also be designed in a number of ways to reduce stress and increase tip flexibility. The catheter shaft can be cut from a hypotube and the lobes can be integrally formed at the distal end of the shaft. In another example, additional lateral flexibility can be obtained by cutting anchoring slots proximate the distal end of the catheter shaft configured to axially constrain the lobe anchors that form the proximal joints of the lobes. The lobes can be anchored longitudinally within the anchoring slots. The slots can be machined through the wall of the catheter body to form a restraining structure for anchoring the lobes. The lobes can extend distally and each lobe can overlap with one or more adjacent lobes to form a flexible petal-like arrangement. The struts of adjacent lobes can cross and can be capable of relative movement such that the tip is unconstrained when deployed to or collapsed from the expanded deployed configuration. In this configuration, the tension cable extending through the catheter body can form a loop around adjacent lobes at the intersections where the lobes overlap. The tension cable loops can engage at intersections that are 180 degrees apart such that tensioning of the tension cable can provide smooth and uniform deployment of the tip.

[0021] The flexible covering may be disposed to form a sleeve around at least a portion of the support tube and at least a portion of the strut framework of the expandable tip. The covering may be a membrane formed from a ductile elastomer, which has the advantage of being soft and flexible with resistance to tearing and puncture due to high strain to failure. Alternatively, the covering may be one or more polymer jackets that may be fused, glued, reflowed, or sewn together to encapsulate at least a portion of the tip. The membrane may be further coated with or made from an elastomer or similar material to provide a low friction surface that facilitates navigation within blood vessels and other catheters.

[0022] In another example, the thrombectomy catheter can have a tubular catheter shaft and an expandable tip integrally formed at the distal end of the catheter shaft. The catheter shaft can have a distal end and a catheter lumen having a longitudinal axis intended therethrough. In some examples, the catheter shaft can have one or more tension cable guide tubes disposed around the circumference of the catheter lumen. The guide tube can house one or more tension cables, the tension cables disposed within a tension cable lumen within the guide tube and capable of being operably tensioned by a user of the catheter using a proximal handle. In some cases, the two tension cables can be spaced 180 degrees apart around the circumference of the catheter shaft.

[0023] The expandable tip may be integrally formed at the distal end of the catheter shaft. The tip and shaft may be formed from a single polymer extrusion or metal tube. The extrusion may be manufactured, for example, from polyetheretherketone (PEEK) or another sturdy thermoplastic polymer. The extrusion may also be laser cut with transverse and / or axial slots to enhance the flexibility of the tube. In one example, the expandable tip may have multiple lobes configured to radially expand from a collapsed delivery configuration to an expanded deployed configuration when one or more tensioning cables are tensioned. The expandable tip may be at least partially encapsulated by one or more outer jackets.

[0024] In one more specific example, the multiple lobes can be two actuating lobes connected to a tensioning cable and two passive lobes circumferentially joined to the actuating lobes. The actuating lobes can be configured to actuate the expandable tip between a collapsed delivery configuration and an expanded deployed configuration when the tensioning cable is tensioned.

[0025] The size and shape of the passive and actuating lobes can be designed to guide the folding and expansion of the expandable tip. The passive lobes can have a substantially horseshoe-shaped profile. The actuating and passive lobes can be of similar size. Alternatively, the actuating lobes can be significantly larger than the passive lobes so as to constitute a substantially larger portion of the expandable tip. In some examples, the actuating lobes can constitute a majority of the circumference of the tip and can be shaped to cause the tip to flare outward, shorten and spread when the tension cable is retracted. This movement of the actuating lobes can help the passive lobes to spread outward, rather than stretching only between the actuating lobes.

[0026] In a further example, the thrombectomy catheter can have a tubular catheter shaft having a distal end and a catheter lumen having a longitudinal axis intended 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 tensioning cables can be fixedly connected to the sliding collar and disposed about the circumference of the catheter lumen. The tensioning cables can be operatively tensioned by a user of the catheter to cause the sliding collar to slide along the catheter shaft.

[0027] 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 multiple distal hoops that overlap circumferentially about the longitudinal axis. The hoops 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 encapsulate the expandable tip.

[0028] In some cases, the hoops may be extensions from the braided wire support structure of the catheter shaft so that there is no abrupt transition in stiffness between the catheter body and the tip. In another example, the lobes may be formed in a braided configuration where adjacent lobes are woven or intertwined some distance proximal to the distal end of the tip. In a similar example, the wire lobes of the expandable tip may be formed independently of the reinforcing wire braid of the catheter body such that the tip and the catheter shaft are separate sections. In this configuration, the proximal ends of the lobes may be anchored within a circumferential sliding collar disposed about the catheter body.

[0029] The distal hoop can be actuated to allow the expandable tip to expand in a number of ways. In one example, a tensioning cable can be connected directly to the distal peak of the hoop. When the cable is tensioned, the overlapping hoops can flare outward radially together, similar to a fan. In another example, the distal hoop can be connected to a sliding collar at its proximal end such that the tensioning cable is tensioned and the collar expands radially as it slides telescopically along the catheter shaft. In a further example, one or more outer jackets encapsulating the tip hoop can be connected proximally to a sliding collar, and when the tensioning cable is tensioned, the jacket and hoop expand radially.

[0030] In the disclosed design, the catheter shaft can have a composite structure that can include an inner layer with a low friction liner such as PTFE and a thick backing layer bonded to the low friction liner. This layer can be assembled as a sleeve over a mandrel with one or more longitudinal grooves and can conform 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 circumferential support for one or more pull wire guide lumens when the guide tube is inserted into the groove. A coil or braid reinforcement layer can then be disposed around the outer diameter of the inner layer. By varying the axial spacing of the coil or braid, variable stiffness characteristics can be provided to different axial lengths of the catheter shaft. A membrane cover can be applied and laminated or fused to the structure. Once bonded, the mandrel can be removed to open the inner catheter lumen.

[0031] Other aspects and features of the present disclosure will become apparent from the following detailed description considered in conjunction with the accompanying figures. Additional features or manufacturing steps may be included as will be recognized and understood by those skilled in the art. [Brief description of the drawings]

[0032] The above and further aspects of the present invention comprise: Consider further with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in the various drawings. The drawings are not necessarily to scale, emphasis instead being placed on illustrating the principles of the invention. The figures depict one or more implementations of the apparatus of the present invention, by way of example only and not by way of limitation. [Figure 1] 1 is a diagram of a clot retrieval catheter having an expandable tip, according to an aspect of the present invention. [Figure 2a] 2A-2C show alternative examples of connecting tension cables to the expandable tip of FIG. 1 according to an embodiment of the present invention. [Figure 2b] 2A-2C show alternative examples of connecting tension cables to the expandable tip of FIG. 1 according to an embodiment of the present invention. [Figure 2c] 2A-2C show alternative examples of connecting tension cables to the expandable tip of FIG. 1 according to an embodiment of the present invention. [Diagram 3] 13A-13C show alternative arrangements for varying the angle at which a tension cable can actuate an expandable tip, according to aspects of the present invention. [Figure 4] 1A-1C show examples of alternative catheters according to aspects of the present invention. [Diagram 5] 5A-5C are diagrams of possible configurations of the shaft from the example of FIG. 4 according to an embodiment of the present invention. [Figure 6] 5A-5C show examples of actuation lobes from the example of FIG. 4 according to an embodiment of the present invention. [Figure 7] 13A-13C show another alternative catheter example according to an aspect of the present invention. [Figure 8] 8 illustrates an expanded profile of the example of FIG. 7, according to an embodiment of the present invention. [Figure 9a] 13A-13C show another alternative catheter example according to an aspect of the present invention. [Figure 9b] 13A-13C show another alternative catheter example according to an aspect of the present invention. [Figure 10] 9a-9b depict possible actuations of the tip of the embodiment of FIGS. 9a-9b according to an embodiment of the present invention. [Figure 11a] 13A-13C show another alternative catheter example according to an aspect of the present invention. [Figure 11b] 13A-13C show another alternative catheter example according to an aspect of the present invention. [Figure 12a] FIG. 1 is an end view of a single extrusion catheter shaft configuration, according to an aspect of the present invention. [Figure 12b] FIG. 2 is an end view of a composite catheter shaft structure according to an aspect of the present invention. [Figure 13a] 1A-1D illustrate a process for the construction of a composite catheter shaft, according to an aspect of the present invention. [Figure 13b] 1A-1D illustrate a process for the construction of a composite catheter shaft, according to an aspect of the present invention. [Figure 13c]1A-1D illustrate a process for the construction of a composite catheter shaft, according to an aspect of the present invention. [Figure 13d] 1A-1D illustrate a process for the construction of a composite catheter shaft, according to an aspect of the present invention. [Figure 14] 1 is a cross-sectional view of a composite catheter shaft construction according to an aspect of the present invention. [Figure 15a] 1A-1C are longitudinal cross-sectional views of catheter shafts having alternative membrane arrangements, in accordance with aspects of the present invention. [Figure 15b] 1A-1C are longitudinal cross-sectional views of catheter shafts having alternative membrane arrangements, in accordance with aspects of the present invention. [Figure 16a] 13A-13C are example diagrams illustrating alternative ways of disposing a membrane cover on an expandable tip, in accordance with aspects of the present invention. [Figure 16b] 13A-13C are example diagrams illustrating alternative ways of disposing a membrane cover on an expandable tip, in accordance with aspects of the present invention. [Figure 16c] 13A-13C are example diagrams illustrating alternative ways of disposing a membrane cover on an expandable tip, in accordance with aspects of the present invention. [Figure 16d] 13A-13C are example diagrams illustrating alternative ways of disposing a membrane cover on an expandable tip, in accordance with aspects of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Specific embodiments of the present invention will now be described in detail with reference to the drawings, in which like reference numbers indicate functionally similar or identical elements. The figures show a thrombectomy catheter having an expandable distal tip. The port of the tip may be formed from a distal ring of material. One or more tensioning cables may be retracted to actuate the distal ring of material and expand it to a deployed state. The tip may expand radially to form a seal with the vessel wall, restricting flow and blocking fluid proximal to the tip, thereby directing more efficient suction distally to retrieve and capture clots. The catheter shaft may have a multi-lumen configuration with a central catheter lumen for passing auxiliary devices and directing suction, and one or more guide lumens through which the tensioning cables may be routed to the expandable tip. A flexible low modulus membrane may be disposed around the expandable tip and at least a portion of the catheter shaft.

[0034] The objective of the disclosed design is to create a clot retrieval catheter that can provide both localized flow restriction / stop and a large mouth facing the clot. The catheter may be capable of navigating the tortuous neurovasculature to reach the occlusive clot, and therefore may be highly flexible. The catheter may also be compatible with relatively low profile access sheaths and catheters, so that the puncture wound in the patient's groin (in the case of femoral access) may be easily and reliably closed. The clot retrieval catheter may be passed through a sheath or guide having an inner diameter of less than 0.110 inches, preferably less than 0.090 inches, in some cases less than 0.087 inches, and most preferably less than 0.085 inches. Thus, the catheter and expandable tip may be capable of a low delivery profile of about 0.084 inches or 2 mm, and furthermore, its distal mouth may be expanded to the size of the vessel in which the clot is located, which may be as large as 5 mm. The tension cable allows the operator to control the diameter of the tip at discrete times during the procedure. The disclosed designs can also allow the user to collapse the tip during or after the procedure.

[0035] Accessing various blood vessels in the vasculature, whether coronary, pulmonary, or cerebral, involves well-known procedural steps and the use of numerous conventional, commercially available accessory products. These products, such as angiographic materials, rotating hemostatic valves, mechanical thrombectomy devices, and guidewires, are widely used in laboratories and medical procedures. When these products are used with the systems and methods of the present invention in the following description, their functions and exact configurations will not be described in detail. Although these descriptions are often related to thrombectomy treatments, the systems and methods can be adapted to other procedures and other body passages as well.

[0036] 1 shows a distal portion of a clot retrieval catheter 100 having a proximal catheter shaft 220 and a distal expandable tip 110. The catheter 100 can be navigated to a target site within a vessel using standard interventional techniques and commercially available ancillary devices such as access catheters, balloon guide catheters, and / or guidewires. The catheter shaft body 220 can have a generally tubular structure disposed about a longitudinal axis 111.

[0037] In one configuration, the tip 110 can have multiple lobes 112, 113 that form an expandable petal shape when unfolded from a folded delivery configuration. The lobes can be struts or wires configured into the shape of loops or hoops. The example shown in FIG. 1 includes two actuating lobes 112 and two passive lobes 113 rigidly connected to the distal end 225 of the catheter shaft 220. The two actuating lobes 112 can be positioned 180 degrees apart and circumferentially overlap the struts of the two passive lobes 113.

[0038] The number of active and passive leaflets can be varied based on the needs of the device, for example, a larger number of leaflets can increase the radial force to support the membrane and form a seal with the vessel wall, but will also increase the lateral stiffness of the tip for a given strut thickness and width.

[0039] In some cases, the lobes 112, 113 can include patterns that would increase flexibility, such as undulations, narrowed sections, or expandable cells. The undulations of the lobes can help the tip shorten or lengthen on the opposite side in the collapsed delivery configuration when advanced to the target site through tortuous vessels. Additionally, the undulations can help prevent one or more lobes or a portion of the tip from over-expanding if the catheter 100 is pushed distally while the tip 110 is expanded. In other examples, the lobes 112, 113 can have a low taper angle and curve radially inward at the distal end when expanded, so that the struts are not forced into the vessel wall.

[0040] The expandable tip 110 may be fixedly or flexibly coupled to the distal end 225 of the catheter shaft 220 at a proximal junction 114 and configured to radially expand from a collapsed delivery configuration within an outer sheath or catheter to a radially expanded deployed configuration. FIG. 1 shows the proximal junction 114 of the fixed lobes. It may be appreciated that the lobes may also be connected via more flexible linkages such as eyelets. The lobes may also have features such as narrowed sections or notches that can act as hinge points for uniform and consistent expansion and folding of the tip 110.

[0041] The catheter shaft 220 can be a multi-lumen system having a main catheter lumen 212 and one or more guide tubes 221 that define a guide lumen 222. The catheter lumen 212 can be used for delivery of auxiliary devices such as microcatheters and stentrivers, and can also be used to direct suction distally through the expandable tip 110. The construction of the shaft 220 can be, for example, a polymeric and / or metallic braided support structure with an internal low friction liner and an outer polymeric jacket that can be reflowed into a braided structure during manufacturing.

[0042] The guide tube 221 can extend axially parallel to the longitudinal axis 111 from a proximal luer or control handle (not shown) that is manipulated by the user. The guide tube can terminate proximal to, distal to, or proximal or distal to the distal end 225 of the catheter shaft 220. The guide tube 221 can function as a conduit for a control member or pull wire cable 120 configured to expand and / or collapse the expandable tip 110.

[0043] The exterior surfaces of the catheter shaft 220 and the expandable tip 110 may be at least partially covered by a membrane or outer jacket (not shown). The membrane or jacket may block proximal fluids from entering the tip during clot aspiration and retrieval, allowing for more efficient direction of suction forces while preventing distal migration of other debris clot fragments during the procedure. In one example, the jacket may be formed from a highly elastic material such that when in an expanded deployed configuration, the radial force exerted by expanding the expandable tip is sufficient to stretch the membrane into a funnel or cone-shaped profile of the tip. Alternatively, the jacket may be loosely folded into a pouch over the lobes to allow the lobes to move freely. A pouch-like jacket folded from the inner diameter to the outer diameter of the tip 110 may have inner and outer surfaces that are glued or heat welded together between the lobe struts to reduce the strain required to expand the jacket and to enhance resistance of the inner portion of the membrane from collapsing under suction.

[0044] 2a-c show various methods of flexible attachment joints between the actuation lobes 112 of the expandable tip 110 and the tensioning cables 120. The tensioning cables 120 may be constructed of steel or high molecular weight polymers with sufficient tensile strength to cause an expansion deflection of the tip 110 when actuated by the user. The tensioning cables 120 help provide a smooth transition during expansion or retraction of the expandable tip and may be circumferentially spaced apart to balance the passive lobes 113 that may not be directly connected to the support tube of the catheter shaft 220. For example, having two actuation lobes 112 spaced 180 degrees apart, such as the configuration of FIG. 1, allows the tip 110 to bend around the bending plane of the two cables 120 as it is advanced to or withdrawn from the target.

[0045] The tensioning cable 120 members may be secured in place at their distal most ends with enlarged bulb ends 118 as shown in Figures 2a and 2b. The bulb ends 118 may be formed during manufacturing after the tensioning cable 120 is fed through an associated eyelet 116 formed on the expandable tip. The eyelet may be located at the proximal end of the tensioning member 115 that extends proximally of the actuation tip lobes 112. The bulbs 118 may be formed by any of several methods, such as by forming a knot, applying heat, laser cutting, molding, or using mechanical plastic deformation. In another example, the eyelet 116 may be a loop formed at the junction of adjacent lobes 112.

[0046] In another example, the bulb can have a polygonal or non-spherical shape that can transmit bending moments to the lobes 112, 113 without a rigidly configured joint in all degrees of freedom, yet still be held by the eyelet 116. Other designs can be envisioned that tune the bending stiffness of the interface between the expandable tip and the catheter body. FIG. 2c shows a further design that can have a flexible hinged joint, where the hinge link 117 forms at the overlapping interface between the tension cable 120 and the tensioning member 115 of the actuation lobe 112. The hinge link 117 can be a single or double pin connection that defines one or more bending planes of the expandable tip 110. A circumferentially aligned double pin connection, for example, would provide a tip that is flexible in two mutually perpendicular planes while maintaining support of the tip from all the lobes. The hinged joint can also be a swivel joint that opens with more degrees of freedom for the tip 110 to bend.

[0047] As shown in FIG. 3, the tensioning cables 120 can exit the guide lumen 222 at the distal end 225 of the catheter shaft 220, or the shaft and guide tube 221 can have a fillet or scallop that forms a distal notch 224 on the outer surface of the shaft. The distal notch 224 can change the tension angle exerted by the tensioning cables 120 on the tensioning member 115 by allowing a shallower exit angle from the cable lumen 222. The notch 224 can be located a specific distance proximal to the distal end 225 of the catheter shaft 220 to fix the exit angle as shown. In another example, the notch can be a slot that extends proximal to the distal end 225. In a further example, an individual tensioning cable 120 can be split to exit two or more distal notches 224 in the catheter shaft 220 such that a single tensioning cable 120 can be used to pull two or more of the actuation lobes 112 around the circumference of the expandable tip 110.

[0048] The tension 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 may be utilized using materials such as PTFE or FEP for lining the guide lumen 222 and / or the outer surface of the tension cable 120. Alternatively, lubricants (such as silicone oil or molybdenum disulfide) may be used, and coatings such as hydrophilic coatings may also be used. The tension cable itself may be made of a very highly elastic material, whereby a thin, low profile cable may be used that exhibits minimal stretch or elongation under tension when in use. Metals such as stainless steel, Nitinol, or MP35N may also be used when the tension cable is in wire or multifilament cable form. Engineered polymers or composites such as UHMWPE, LCP, Vectran, or Kevlar may also be envisioned as suitable materials. In addition, combinations of both wire and cable and / or metal and polymer may also be used. For example, solid Nitinol wire with a PTFE coating can be used for the majority of the tension cable, and a short segment of UHMWPE near the distal end can be used to help connect the tension cable to the actuation lobes 112 of the expandable tip 110. A proximal solid monofilament can also be used to provide good pushability and column stiffness within the tension cable so that it can be advanced to collapse the frame if necessary.

[0049] In another configuration shown in FIG. 4, the catheter 100 can have a tubular catheter shaft 220 configured about a longitudinal axis 111. The catheter shaft 220 can have longitudinal and / or transverse cuts 228 machined into its surface at regular or variable intervals so that the flexibility of the catheter 100 can be tailored along its length. For example, the slots can be sized or spaced such that the proximal portion of the catheter provides better pushability and trackability characteristics. Different slot spacing along the more distal length of the shaft 220 can allow for greater flexibility for narrow and tortuous vessels near occlusive clots.

[0050] The illustrated catheter shaft 220 can have two guide tubes 221 spaced 180 degrees apart on either side of the shaft circumference. The guide tubes 221 can be used to route the pull cable 120 for actuating the expansion and collapse of the distal expandable tip 110. The guide tubes 221 can run the entire length of the catheter shaft and circumferentially interrupt a transverse cut or slot 228 in the shaft to form a longitudinally extending spine 230. The axial spine 230 can have a constant thickness or can be tapered to provide a smooth stiffness transition between the proximal and distal portions of the catheter shaft 220.

[0051] In the example shown in Figures 4-6, the expandable tip 110 has six strut segments forming lobes 124 with six distal peaks 119. The lobes 124 may be laser cut integrally with the polymer catheter shaft 220, machined as separate members (as shown in Figures 4-6), or may be a combination of integral and independent members. Adjacent lobes 124 may overlap circumferentially at intersections 126. The lobes need not be fixedly connected at the intersections, such that they are interleaved and may slide and fold over one another as the tip 110 expands or contracts. It can be appreciated that designs with more than six lobes sacrifice some tip flexibility while the additional lobe struts provide additional radial force and support to prevent the jacket or membrane (not shown) from collapsing. Similarly, fewer lobes may be utilized in situations where a membrane of greater stiffness or thickness requires less support.

[0052] One or more tensioning cables 120 may extend along the length of the shaft 220 within the guide lumen 222 of the guide tube 221. The tensioning cables 120 may be formed with a distal loop 122 configured to encircle the intersection 126 where two adjacent lobes 122 overlap. When tensioned, the tensioning cables 120 may pull the intersection 126 outward to increase the radial size and deploy the expandable tip 110. In some cases, the guide tube 221 of the shaft 220 may have a distal extension 227 beyond the distal end 225 of the shaft.

[0053] FIG. 5 shows the catheter shaft 220 of the catheter 100 of FIG. 4. Anchoring slots 226 may be located proximal to the distal end 225 of the shaft 220 to provide rigidity and retention to the proximal joint 114 between the shaft and the lobes 124 of the distal tip 110. Separate adjacent lobes 124, such as the example shown in FIG. 6, may have a hoop shape with distal peaks 119 and proximal feet or anchors 128. The lobes 124 may be arranged in an alternating fashion and their proximal lobe anchors 128 may be laser welded or bonded together within the anchoring slots 226 of the shaft 220. In another example, some of the lobes may be integrally formed with the shaft while other lobes have anchors 128 welded or bonded onto the shaft. As another alternative, a collar surrounding the distal end 225 of the shaft 220 can act as a retaining ring to control the axial movement of the lobe anchors 128 (an example of which is shown in FIG. 9a).

[0054] A distal portion of another example of a thrombectomy catheter according to an embodiment of the invention is shown in FIG. 7. A tubular catheter shaft 220 may be formed from a polymer extrusion. The extrusion may be manufactured, for example, from polyetheretherketone (PEEK) or another sturdy thermoplastic polymer. The extrusion may be configured with axial and / or transverse slots 228 cut into the exterior surface to provide additional lateral flexibility to the tubular shaft 220. The cuts may be aligned or offset longitudinally to tailor stiffness characteristics for different axial sections of the shaft 220. The slots 228 may be circumferentially discontinuous to form one or more longitudinal spines 230 along the length of the shaft 220.

[0055] One or more tension cable guide tubes 221 may be disposed around the circumference of the catheter body 220 and may extend the length of the catheter shaft. The tubes 221 may be flush against the outer surface of the catheter tube, or may be mid-wall or some other arrangement. As shown, some embodiments may have two tension cables spaced 180 degrees apart around the circumference of the catheter shaft, but other spacing arrangements may be envisioned when more cables are utilized. The guide tubes 221 may or may not be radially aligned with one or more longitudinal spines 230, so that the tubes can act as additional stiffening mechanisms if desired. Each guide tube may have an inner tubular lumen 212 sized to allow free relative axial movement of the tension cables 120. As with other designs, a distal notch 224 may be provided to allow radial bending of the tension cables 120 when tension is applied. The guide tubes may be a sturdy polymer tube that offers good column stiffness and kink resistance, such as a polyimide tube.

[0056] The funnel design of the expandable tip 110 in this example can be an integral lattice of lobes 240, 241 laser cut directly with the catheter shaft 220. Alternatively, the expandable tip 110 lattice can be injection molded as a single piece and attached to the shaft 220 by heat welding, adhesive, or similar means. The actuation lobes 240 can be operatively coupled to the tensioning cable 120 in configurations similar to those previously described, such as knots, loops, or eyelets. The lobes 240, 241 can be rounded distally with gently sloping loops or petal shapes for atraumatic contact with the vessel wall when expanded. The lobes 240, 241 can include bends such that the lobes 240, 241 can or can be shortened or widened when the tip 110 flares outward as the tensioning cable 120 is retracted. As with other embodiments, a polymer jacket or membrane can cover or encapsulate the tip section 110 and at least a portion of the catheter shaft 220.

[0057] 7 shows the expandable tip 110 in a collapsed delivery configuration. The tip 110 can include two actuating lobes 240 and two passive lobes 241 rigidly connected to the distal end 225 of the catheter shaft 220. The two passive lobes 241 can be circumferentially joined to the actuating lobes 240 at circumferential joints 229, which can be fixedly connected to one of the tension cables.

[0058] The actuation lobes 240 can occupy a substantially larger portion of the circumference of the expandable tip 110 than the passive lobes 241. As seen in FIG. 7, the passive lobes 241 can have a substantially horseshoe-shaped profile, where the legs of the horseshoe are circumferentially compressed together when the tip 110 is in the folded delivery configuration. The shape of the actuation lobes 240 can be adjusted so that they shorten and spread out (as well as flaring outward) when the tensioning cable 120 is retracted. This shape will help the adjacent passive lobes 241 flare out when tensioned at the circumferential joint 229, thus creating a more rounded funnel as opposed to simply being stretched into an egg-shaped funnel shape.

[0059] 7 is shown in an expanded deployed configuration in FIG. 8. The passive lobes 241 can be shorter and intersect at circumferential joints 229 along the length of the actuating lobes 240, causing the passive lobes to flare to a larger radial size. The combined flaring of all the lobes contributes to a more rounded, uniform funnel that is better formed to form a seal with the vessel and to receive and compress the trapped clot as it dislodges. In the illustrated embodiment, the membrane or jacket 430 can be trimmed to follow the contours of the expanded mouth of the tip 110. In other examples, the jacket 430 can follow a square or atraumatic concave profile.

[0060] 9a and 9b show another configuration of a funnel-shaped catheter tip 300 in which the lobes are formed from a braided or coiled woven structure 310. The wires of the lobes can form overlapping distal hoops 312 that can be interleaved and secured within a sliding collar 320 that can slide telescopically along the axis 111 of the catheter. 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 to tailor local stiffness characteristics to the axial section of the catheter shaft 220. The distal hoops 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, the hoops form a gentle funnel profile for the expanded tip 300, as shown in FIG. 9b.

[0061] In one example, where the braided structure 310 of the expandable tip 110 and the catheter shaft 220 may be integrally formed, a pull wire (not shown) may be looped around the weave intersection 314 for expansion of the tip 110 to a deployed configuration. In another example, the wires of the distal hoop may be fixed directly to the catheter body 220 or extend proximally with the proximal junction 114 embedded within the outer polymer jacket 430. The weave intersection 314 of the distal hoop 312 may be kept as distal as possible. The distal hoops 312 may be free to move and slide relative to one another.

[0062] The braided mesh can have a metal wire structure and can utilize alloys with shape memory properties such as Nitinol. To form the braided mesh, a unitary wire can be wrapped around a forming tool with a tapered bullet-shaped nose and heat set to a distally decreasing outer diameter at the tip for atraumatic crossing within the vessel. The wire outer diameter can be relatively large to give the wire increased stiffness to aid in opening the elastomeric membrane. In one example, the wire outer diameter can range from 0.004 inches to 0.008 inches. A segment of the wire can be flattened with a press tool to maximize flow rate and the proximal cross section of the tip to accommodate the clot. The distal section of the wire that forms the expandable tip that opens upon actuation can also be flattened, but this section can also remain rounded since the increase in diameter of the tip in the expanded deployed state does not affect the cross section.

[0063] An example of an actuation mechanism for the example tip shown in FIG. 9a to a deployed configuration is shown in FIG. 10. A collar 320 may be slidably disposed around at least a portion of the catheter shaft 220 and configured to translate along the longitudinal axis 111 of the catheter through tensioning or pushing of one or more tensioning cables 120. The distal hoop 312 may have a hoop tensioning member 322 connected to the sliding collar 320. The tensioning member 322 may be a wire or strip and may be connected to some or all of the hoops 312 of the braided structure 310 of the expandable tip 300. The tensioning member 322 may then flare and expand the tip when the collar 320 is pulled proximally with the tensioning cables 120. The strands of the distal hoop 312 may be embedded in or otherwise connected to the shaft 220 such that the collar expands radially when pulled and translated proximally. The pulling force can be evenly distributed to the hoop 312 through two pulling cables 120 spaced 180 degrees apart.

[0064] Alternatively, at least a portion of the outer jacket or membrane 430 can be inverted over the expandable tip 110 and coupled to the slidable collar 320. The membrane 430 can extend radially inward of the hoop 312, which is coupled to the inner diameter of the shaft 220. The membrane 430 can then radially expand the hoop 312 when the collar 320 is pulled proximally along with the tension cable 120.

[0065] It should be noted that any of the catheter designs disclosed herein may also be used with one or more stentrivers. The combination of retraction of the stentriver and efficient aspiration through the enlarged tip section in the expanded deployed configuration can work together to increase the chances of first-pass success in removing the clot. The catheter can also direct an aspiration vacuum to the clot surface, while the stentriver can hold the composite clot (composed of friable and fibrin-rich regions) together to prevent embolization and assist in dislodging the clot from the vessel wall. The funnel-shaped shape of the tip section can also reduce shearing of the clot upon entry into the catheter, halting flow and protecting the distal vessel from embolization of new areas.

[0066] 11a and 11b show additional configurations of a funnel-shaped catheter tip 300 in which the lobes are formed from a braided or coiled woven 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 may enable actuation of the tip from two pull wires 120 to transfer force from diametrically opposed actuation lobes 340 to adjacent passive lobes 341, thereby moving all lobes from a substantially tubular, collapsed delivery state as shown to an open, deployed configuration for aspiration and / or device delivery. In one example, the pull wires 120 may be attached to braid loops or eyelets 316 at the distal end 325 of the actuation lobes 340. In another example, the pull wires 120 may simply be welded to the center of the distal end 325 of the actuation lobes 340 or attached at the weave crossover 314.

[0067] As shown in FIG. 11a, the actuation lobes 340 may be positioned below (radially inward) each of the adjacent passive lobes 341, so that by applying tension to a pull wire (not shown), all of the lobes can be opened in a balanced manner. Proximally, the struts of the lobes 340, 341 may each have a single twist at the cross lobe lay point 342, which may help anchor the lobes relative to one another and may act as a pivot for radial expansion of the tip 300. Alternatively, a spot weld between the lobes at the lay point 342 may fix the position. The advantage of this configuration is that the connections between the pull wires and the actuation lobes do not need to be slidable, since the lobes 340, 341 can slide relative to one another at the cross point 314 when the expandable tip is open.

[0068] In another configuration, the pull wires 120 of the tip 300 can be looped over the distal lobe intersection 314 similar to the expandable tip seen in FIG. 4. This configuration allows the tension of the pull wires to be more evenly translated to the expanding lobes. In this configuration, the actuating lobes 340 can be positioned above (radially outward) or below (radially inward) the adjacent passive lobes 341. However, the pull wire attachment at the intersection 314 must be slidable, allowing the intersection to slide to a more proximal position as the lobes are radially expanded.

[0069] The braided tissue member 310 may be covered with a membrane or outer jacket 430, as shown in Figure 11b. The jacket 430 may extend distally from the inner diameter of the catheter under the lobes 340, 341 of the tip section 300 and invert at the distal end 325 to extend proximally over the lobes. The inverted jacket 430 does not need to be glued to the tip section in this design, so the lobes are free to move relative to each other within the inverted jacket sock.

[0070] As in the previous example, the tension cable guide tube 221 may extend longitudinally with the catheter shaft 220. In some examples, the tension cable 120 may extend distally from the guide tube under the braided lobes 340, 341. This orientation may facilitate catheter assembly at the expense of reducing tension leverage for tip actuation 300, as the twist points 342 may limit radial movement of the tension cable 120 as the tip is expanded. In other examples, tip actuation extension leverage may be maintained by threading the tension cable 120 over the lobes 340, 341 so that there is no restriction as the tension cable exits the guide tube 221. This configuration may allow for greater opening forces to be generated, but may result in more difficult catheter assembly than if the tension cable was threaded under the lobes.

[0071] Various manufacturing methods can be used to manufacture the catheters of the embodiments disclosed herein. Figures 12a-b show transverse end views of a possible construction method for a catheter shaft 220 of a clot retrieval catheter. In Figure 12a, the shaft can be a one-piece multi-lumen extrusion that is laser cut to add flexibility. For example, the shaft 220 can have a helical cut section between the proximal and distal ends. The cuts can include a change in cut width such that a series of narrow transverse slots aligned longitudinally can form one or more axial spines 230 parallel to the guide tubes 221 in the extrusion. The axial spines can provide good pushability of the shaft while maintaining shaft flexibility. The multi-lumen shaft 220 can have twin guide tubes 221 with tension cable lumens 222 spaced 180 degrees apart. At least one of the pair of tension cable lumens 222 can also have an internal tether (not shown) running therethrough to prevent excessive stretching of the shaft under tension. In one example, the tether can be made of a fluoropolymer or other material that provides resistance to stretching. The limited stretching allows the extrusion incisions to open when the shaft 220 is in a tight radius within the vessel. The tether can also resist the incisions from being substantially pulled apart under greater tension, such as when the expandable tip needs to be retracted into the outer sheath or intermediate catheter when a tough, fibrin-rich clot is lodged at the tip.

[0072] In one example, the catheter can have a shaft with 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 abutting and traversing the inner wall of the extrusion, it can be understood that the tension cable guide tube 221 and lumen 222 can also be located outside the middle or outer wall of the extrusion.

[0073] The extrusion can be a highly elastic thermoplastic polymer such as PEEK, polyamide (Pa), or nylon such as TR 55, giving the shaft excellent pushability. Additionally, the extrusion material can be a highly elastic, low friction polymer to aid in the passage of other devices for the procedure, such as microcatheters, stentreaver, and guidewires. A heat shrunk outer jacket or membrane 430 (not shown) can seal the extrusion of the shaft 220 when fused to the outer diameter of the shaft.

[0074] In another example, a low friction layer or film can be applied to the inner diameter of the shaft 220 through the use of a small PTFE or other low friction liner with an outer backing layer for bonding that can be positioned inside the extrusion. A heated mandrel with an enlarged end can then be drawn through the liner, expanding it and bonding it to the inner surface of the laser cut extrusion. Additional heat can be applied to the extrusion as needed to fuse the liner.

[0075] 12b shows an alternative shaft 220 of layered composite construction. The layers can include a low friction inner sleeve or liner 410 and a tubular core 420 to which an outer jacket or membrane 430 can be applied. The core can be an extrusion, laser cut hypotube, or a coiled or braided mesh to provide structure and reinforcement for the catheter shaft 220.

[0076] The composite layered catheter shaft 220 may be described through a method for construction as shown in Figures 13a-13d. In Figure 13a, a substantially cylindrical mandrel 400 may be fabricated, which may have an outer diameter approximately the same as the desired inner diameter of the catheter shaft 220. The mandrel 400 may have one or more longitudinal lumen grooves 402 machined into its outer surface parallel to the longitudinal axis 111, which act as a mold for the tension wire guide tube 221.

[0077] In FIG. 13b, the composite structure can include a flexible inner layer 410 having a low friction liner 411, such as PTFE or PET, and a thick backing 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 FIG. 13c, a polyamide or similar tube forming the luminal guide tube 221 can be inserted into the luminal groove 402 of the mandrel 400 to force the inner layer 410 into the groove. A coil or braided reinforcement layer 420 can then be wrapped or disposed around the outer diameter of the inner layer 410 and the guide tube 221. As previously mentioned, the pitch or axial spacing of the coil or braided reinforcement 420 can be varied to adjust stiffness characteristics for different axial lengths of the catheter shaft 220. The reinforcement coil 420 can securely tie the guide tube 221 to the inner layer 410. In another example, 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.

[0078] As used herein, the terms "jacket," "membrane," and "cover" are used interchangeably. An outer jacket or membrane 430 can be applied over the top of the composite structure and reflowed using heat shrink or lamination to hold the assembly together. In some cases, the jacket can have several sections with different material properties. In FIG. 13d, once the jacket or membrane 430 is secured in place, the grooved mandrel 400 can be removed.

[0079] Figure 14 is a cross-sectional view of a composite catheter shaft 220 configuration that can result from the method of Figures 13a-13d. The outer jacket can be a membrane cover 430 and can take a variety of different forms or configurations, as will be further described. The membrane or cover can be formed in a tubular profile with a highly elastic material such that expansion of the expandable tip provides sufficient radial force to stretch the cover when unconstrained. The cover 430 can also be preformed into a tapered funnel shape with pleats or folds 432, allowing it to fold down to a lower profile for delivery.

[0080] Suitable jacket materials can include elastomeric polyurethanes such as Chronoprene, which can have a Shore hardness of 40A or less, or silicone elastomers. If the catheter shaft 220 and tip framework are formed from a polymer extrusion, spaces, slots, or patterns can be laser cut into the exterior surface and the jacket can be reflowed or injection molded into the spaces during manufacturing. Alternatively, the jacket can be laminated to the structure.

[0081] To allow for smooth delivery of the clot retrieval catheter 100 through the outer catheter, the exterior surface of the membrane 430 may be coated with a low friction or lubricious material such as PTFE, or a commercially available lubricious coating such as those offered by Surmodics, Harland, Biocoat, or Covalon. Similarly, the interior surface of the catheter shaft 220 may also be coated with the same or a similar low friction material to allow for the passage of auxiliary devices and to assist captured clots in being pulled proximally through the catheter 100 using suction and / or mechanical thrombectomy devices.

[0082] In other examples, the jacket or membrane may be a straight extrusion and may be extruded and post-formed onto the expandable tip and catheter body. Alternatively, if the catheter shaft and expandable tip have laser cut struts, coils, or braided structures, the structures may be encapsulated within the membrane as part of a dip coating or plasma deposition process.

[0083] The cover may be trimmed to follow the contour of the expandable tip's ostium along the periphery of the ostium, or may be completed with a planar surface. In another example, the cover membrane may be folded radially inward and proximal to the distal peaks of the lobes and welded between the inner and outer layers. The thickness of the cover may be maintained between and over the tip lobes, or may be completed with a uniform thickness.

[0084] Alternatively, the jacket or membrane 430 may also be formed from a series of layers of polymer jackets 238, as shown in Figures 15a and 15b. For example, the polymer jackets 238 of the cover may be in radial rows disposed about the catheter shaft 220 to tailor the material properties through the thickness, as shown in Figure 15a. Alternatively, different durometer jackets or sets of jackets 238 may be disposed about the catheter shaft 220 at distinct lengths along the axis to give distinct sections of the catheter distinct pushability and flexibility properties, as shown in Figure 15b. By configuring the jackets in axial rows, it is possible to transition the overall stiffness of the catheter from stiffer at the proximal end to very flexible at the distal end.

[0085] A series of polymer jackets 238 can be butted together and fused to the catheter shaft 220. The expandable tip can have the same or a separate jacket, which can be dip coated, and can abut, underlie, or overlie the catheter shaft jacket. If the tip jacket is under the shaft jacket, it can be made from a material capable of withstanding the heat generated when the support tube jacket is reflowed. In a further example, a preformed outer jacket with variable stiffness and elastic properties can be replaced with a series of polymer jackets.

[0086] 16a-16d briefly illustrate some examples of how the jacket 430 may be disposed around the unexpanded tip 110 toward the distal end of the catheter shaft 220. FIGS. 16a-16b illustrate examples where the jacket 430 is applied with folds or pleats 432 to allow for folding for a low profile delivery state in situations where a large or pouch-like jacket is used. The pleats 432 may then be deployed when the tip 110 is expanded to a deployed configuration. The jacket 430 may overlap and extend around the expanded petals or leaves of the tip to minimize strain imparted on the jacket as the tip expands. In a similar embodiment, the jacket 430 may be slightly larger for the expandable tip, and a combination of deployment pleats 432 and elastic expansion of the jacket may be used to conform the jacket to the contours of the expanded tip.

[0087] FIG. 16c shows a profile cross-section of the distal portion of the catheter 100 with a coating membrane 430 applied over the expandable tip 110. The membrane 430 may be dipped or deposited in a plasma process and then laminated to the frame. The membrane edges may be trimmed to follow the distal edge of the tip 110 or may be left as a flat surface. In a separate embodiment shown in FIG. 16d, the membrane 430 may be folded or inverted around the frame of the tip 110 such that a soft, atraumatic lip 434 is created. The membrane 430 may be fused to the tip 110 or the tip structure may be configured to slide freely within the lip 434.

[0088] The present invention is not necessarily limited to the described examples, which may vary in configuration and details. The terms "distal" and "proximal" are used throughout the foregoing description and are meant to refer to a location and direction relative to the treating physician. Thus, "distal" or "distally" refers to a location away from or a direction away from the physician. Similarly, "proximal" or "proximally" refers to a location closer to or a direction toward the physician. Additionally, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0089] The term "about" or "approximately" as used herein with respect to any numerical value or range of numerical values ​​indicates a suitable dimensional tolerance that allows a portion of a component or a collection of components to function according to its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±20% of the recited value, for example, "about 90%" may refer to a range of values ​​of 71% to 99%.

[0090] In describing the exemplary embodiments, technical terms are utilized for clarity. Each term is intended to have its broadest meaning as understood by a person skilled in the art, and is intended to include all technical equivalents that operate in a similar manner to achieve similar purposes without departing from the scope and spirit of the present disclosure. It should also be understood that a reference to one or more steps of a method does not preclude the presence of additional method steps or intervening method steps between those steps that are explicitly identified. Some steps of a method can be performed in a different order than the order described herein without departing from the scope of the disclosed technology. Similarly, it should also be understood that a reference to one or more components in an apparatus or system does not preclude the presence of additional components or intervening components between those components that are explicitly identified. For clarity and conciseness, not all possible combinations have been listed, and such modifications will often be apparent to those skilled in the art and are intended to be within the scope of the following claims.

[0091] [Embodiment] (1) A thrombus removal catheter, comprising: 1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; one or more tension cable guide tubes including a tension cable lumen disposed about the circumference of the catheter lumen and extending a longitudinal length of the catheter shaft; a tubular catheter shaft including one or more tension cables disposed within the tension cable lumen and operable to be tensioned by a user of the catheter; an expandable tip having a collapsed delivery configuration and a radially expanded deployed configuration, the tip including one or more lobes about the longitudinal axis and configured to assume a funnel profile when the expandable tip is in the expanded deployed configuration; the one or more tensioning cables are configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when tension is applied to the tensioning cables. (2) the plurality of lobes includes one or more actuating lobes and one or more passive lobes; A catheter as described in embodiment 1, wherein the one or more working lobes and the one or more passive lobes comprise looped struts including a distal peak and one or more proximal junctions connected to the catheter shaft. (3) The catheter of embodiment 2, wherein the actuating lobes and the passive lobes are configured to slide over each other when the expandable tip transitions between the folded delivery configuration and the radially expanded deployed configuration. (4) The catheter of embodiment 2, wherein the catheter shaft further comprises one or more distal notches from the tension cable guide tube proximate the distal end, the distal notches configured to allow the tension cable to exit the tension cable lumen at a shallow angle relative to the longitudinal axis. (5) The catheter of embodiment 2, wherein each of the one or more actuating lobes further comprises a tensioning member extending distally from the distal peak of the lobe and fixedly connected to a tensioning cable.

[0092] (6) The catheter of embodiment 5, wherein the tension cable is connected to the tensioning member through a hinge link. (7) The catheter of claim 5, wherein the tension cable includes a bulb connected to an eyelet of the tensioning member. (8) The catheter of embodiment 2, wherein the tension cable comprises a distal loop configured around the looped strut of the one or more actuating lobes. (9) The catheter of embodiment 2, wherein the proximal joint of the lobe includes a lobe anchoring portion configured to engage with a plurality of anchoring slots proximate the distal end of the catheter shaft. (10) The catheter of embodiment 2, wherein the tension cable guide tube extends a distal distance further relative to the distal end of the catheter shaft.

[0093] (11) The catheter of embodiment 2, wherein the expandable tip is at least partially encapsulated by one or more outer jackets. (12) A thrombus removal catheter, comprising: 1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; a tubular catheter shaft including one or more tension cable guide tubes disposed about a circumference of the catheter lumen, the guide tubes having one or more tension cables disposed within the tension cable lumen and capable of being operably tensioned by a user of the catheter; an expandable tip integrally formed at the distal end of the catheter shaft, the expandable tip including a plurality of lobes configured to radially expand from a collapsed delivery configuration to an expanded deployed configuration when the one or more tensioning cables are tensioned. (13) The catheter of embodiment 12, wherein the expandable tip is at least partially encapsulated by one or more outer jackets. (14) The catheter of embodiment 12, wherein the one or more tension cables include two tension cables spaced 180 degrees apart around the circumference of the catheter shaft. (15) The plurality of lobes includes two actuating lobes and two passive lobes circumferentially joined to the actuating lobes, each of the actuating lobes being fixedly connected to one of the two tension cables; 15. The catheter of claim 14, wherein the actuation leaflets are configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when the tensioning cable is tensioned.

[0094] (16) The catheter of embodiment 15, wherein the passive leaflets have a substantially horseshoe-shaped profile. (17) The catheter of embodiment 15, wherein the working lobes comprise a substantially larger portion of the circumference of the expandable tip than the passive lobes. (18) A thrombus removal catheter, comprising: 1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; a sliding collar disposed about the catheter shaft and configured to telescopically slide along the longitudinal axis; a tubular catheter shaft including one or more tensioning cables fixedly connected to the sliding collar and disposed about the circumference of the catheter lumen, the one or more tensioning cables being operatively tensionable by a user of the catheter to slide the sliding collar; an expandable tip proximate the distal end having a collapsed delivery configuration and a radially expanded deployed configuration, the tip including a plurality of distal hoops circumferentially overlapping about the longitudinal axis and configured to form a funnel profile when the expandable tip is in the expanded deployed configuration; and one or more outer jackets at least partially encapsulating the expandable tip. (19) The catheter of embodiment 18, wherein the distal hoops are connected at their proximal ends to the sliding collar, and the distal hoops are configured to radially expand when the tensioning cable is tensioned. (20) The catheter of embodiment 18, wherein the one or more outer jackets are proximally connected to the sliding collar, and the jackets are configured to radially expand the distal hoop when the tensioning cable is tensioned.

Claims

1. 1. A thrombus removal catheter, comprising:

1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; one or more tension cable guide tubes including a tension cable lumen disposed about the catheter lumen and extending a longitudinal length of the catheter shaft; a tubular catheter shaft including one or more tension cables disposed within the tension cable lumen and operable to be tensioned by a user of the catheter; an expandable tip having a collapsed delivery configuration and a radially expanded deployed configuration, the expandable tip including two or more lobes about the longitudinal axis and configured to assume a funnel profile when the expandable tip is in the expanded deployed configuration; the tensioning cable is configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when tension is applied to the tensioning cable; each of the first and second lobes of the two or more lobes includes a looped strut including a distal peak and one or more proximal junctions connected to the catheter shaft; a catheter shaft extending from the distal end of the catheter to the distal end of the catheter, the catheter shaft further comprising one or more distal notches extending from the distal end of the catheter shaft to the distal end of the catheter, the distal notches being configured to allow the tension cable to exit the tension cable lumen at a shallow angle relative to the longitudinal axis.

2. A catheter as described in claim 1, wherein the first lobe and the second lobe are configured to slide relative to one another as the expandable tip transitions between the folded delivery configuration and the radially expanded deployed configuration.

3. 1. A thrombus removal catheter, comprising:

1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; one or more tension cable guide tubes including a tension cable lumen disposed about the catheter lumen and extending a longitudinal length of the catheter shaft; a tubular catheter shaft including one or more tension cables disposed within the tension cable lumen and operable to be tensioned by a user of the catheter; an expandable tip having a collapsed delivery configuration and a radially expanded deployed configuration, the expandable tip including two or more lobes about the longitudinal axis and configured to assume a funnel profile when the expandable tip is in the expanded deployed configuration; the tensioning cable is configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when tension is applied to the tensioning cable; each of the first and second lobes of the two or more lobes includes a looped strut including a distal peak and one or more proximal junctions connected to the catheter shaft; the first lobe further comprising a tensioning member extending proximally from the distal peak of the first lobe and fixedly connected to the tension cable; when the tension cable is pulled, the first lobe deforms, a force is transmitted from the first lobe to the second lobe causing the second lobe to deform, and the expandable tip is actuated from the collapsed delivery configuration to the expanded deployed configuration.

4. The catheter of claim 3 , wherein the tension cable is connected to the tensioning member through a hinge link.

5. The catheter of claim 3 , wherein the tension cable includes a bulb connected to an eyelet in the tensioning member.

6. 1. A thrombus removal catheter, comprising:

1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; one or more tension cable guide tubes including a tension cable lumen disposed about the catheter lumen and extending a longitudinal length of the catheter shaft; a tubular catheter shaft including one or more tension cables disposed within the tension cable lumen and operable to be tensioned by a user of the catheter; an expandable tip having a collapsed delivery configuration and a radially expanded deployed configuration, the expandable tip including two or more lobes about the longitudinal axis and configured to assume a funnel profile when the expandable tip is in the expanded deployed configuration; the tensioning cable is configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when tension is applied to the tensioning cable; each of the first and second lobes of the two or more lobes includes a looped strut including a distal peak and one or more proximal junctions connected to the catheter shaft; the tension cable includes a distal loop configured around the looped post of the first lobe; when the tension cable is pulled, the first lobe deforms, a force is transmitted from the first lobe to the second lobe causing the second lobe to deform, and the expandable tip is actuated from the collapsed delivery configuration to the expanded deployed configuration.

7. 1. A thrombus removal catheter, comprising:

1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; one or more tension cable guide tubes including a tension cable lumen disposed about the catheter lumen and extending a longitudinal length of the catheter shaft; a tubular catheter shaft including one or more tension cables disposed within the tension cable lumen and operable to be tensioned by a user of the catheter; an expandable tip having a collapsed delivery configuration and a radially expanded deployed configuration, the expandable tip including two or more lobes about the longitudinal axis and configured to assume a funnel profile when the expandable tip is in the expanded deployed configuration; the tensioning cable is configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when tension is applied to the tensioning cable; each of the first and second lobes of the two or more lobes includes a looped strut including a distal peak and one or more proximal junctions connected to the catheter shaft; the proximal junction of each of the first and second lobes includes a lobe anchor configured to engage an anchoring slot proximate the distal end of the catheter shaft.

8. 1. A thrombus removal catheter, comprising:

1. A tubular catheter shaft comprising: a catheter lumen having a distal end and a longitudinal axis extending therethrough; one or more tension cable guide tubes including a tension cable lumen disposed about the catheter lumen and extending a longitudinal length of the catheter shaft; a tubular catheter shaft including one or more tension cables disposed within the tension cable lumen and operable to be tensioned by a user of the catheter; an expandable tip having a collapsed delivery configuration and a radially expanded deployed configuration, the expandable tip including two or more lobes about the longitudinal axis and configured to assume a funnel profile when the expandable tip is in the expanded deployed configuration; the tensioning cable is configured to actuate the expandable tip between the collapsed delivery configuration and the expanded deployed configuration when tension is applied to the tensioning cable; each of the first and second lobes of the two or more lobes includes a looped strut including a distal peak and one or more proximal junctions connected to the catheter shaft; The tension cable guide tube further extends a distal distance relative to the distal end of the catheter shaft.

9. The catheter of claim 1 , wherein the expandable tip is at least partially encapsulated by one or more outer jackets.

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