Actuating the clot retrieval catheter

Abstract

The present invention is entitled "Actuated Clot Retrieval Catheter". The device described herein includes an actuated clot retrieval catheter system. The system includes a catheter having a frame disposed proximate a distal end of the catheter. The frame expands to form a seal with an inner wall of a vessel. In some examples, the frame also captures a clot for removal from the vessel. The frame is made of a shape memory material that can be heat-set into a predetermined shape. An electrical connection to an electrical circuit causes an electric current to flow through the frame. The resistance of the shape memory material causes the frame to heat and transform from a martensite phase to an austenite phase. When the frame is heat-set into an expanded configuration, the electric current causes the frame to heat and expand. When the frame is heat-set into a closed configuration, the electric current causes the frame to heat and collapse on the clot.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to and the benefit of U.S. Provisional Application No. 62 / 813,723, filed on March 4, 2019, under 35 U.S.C. §119(e), which is incorporated herein by reference as if fully set forth below. Technical Field

[0003] The present disclosure generally relates to devices and methods for removing acute blockages from blood vessels during endovascular medical treatments. More specifically, the present disclosure relates to an actuated clot retrieval catheter. Background Art

[0004] Clot retrieval catheters and devices are typically used in mechanical thrombectomy for endovascular intervention in patients with conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing distant areas such as neurovascular beds is challenging using conventional techniques because the target vessels are small in diameter, distal relative to the insertion site, and highly tortuous.

[0005] The clot itself can complicate the procedure by taking on a variety of complex morphologies and consistencies, ranging from simple tubular structures that take the shape of a vessel to long, chain-like arrangements that can span multiple vessels simultaneously. The age of the clot can also affect its compliance, with older clots tending to be less compressible than fresh clots. Fibrin-rich clots also present the challenge of the sticky nature that can cause the clot to roll along the outer surface of a mechanical thrombectomy device rather than being effectively grasped. Combinations of soft and hard clot regions can also be separated during aspiration, where rupture can result in distal embolism, which can occur in vessels that are inaccessible to currently available devices. In addition, disrupting the adhesion of the clot to the vessel wall without damaging the fragile vessel is a major challenge.

[0006] Conventional clot retrieval catheters, especially those used for operation in neurovascular vessels, can have a number of disadvantages. First, the diameter of the catheter itself must be small enough to be advanced into the vasculature, which is very small in the case of the neurovascular system. The catheter must also be flexible enough to conduct the vasculature and withstand high strains, while also having axial stiffness to provide smooth advancement along the route. Once the target site is reached, the size of a typical object to be retrieved from the body can be substantially larger than the catheter tip, making it more difficult to retrieve the object into the tip. For example, fibrin-rich clots are often difficult to extract because they can deposit at the tip of a conventional fixed-opening catheter. This deposition can cause the softer portion of the clot to be cut away from the harder area, resulting in distal embolism.

[0007] Small diameter and fixed tip size may also be less efficient in the aspiration necessary to remove blood and thrombotic material during guided surgery. The aspiration suction must be strong enough so that any fragmentation that occurs through the use of a mechanical thrombectomy device or other method can be kept stationary to a minimum so that the debris cannot migrate and block the distal vessels. However, when aspirating with a conventional fixed opening catheter, a significant portion of the aspiration flow ultimately comes from the vascular fluid near the catheter tip, where there is no clot. This significantly reduces the efficiency of aspiration, thereby reducing the success rate of clot removal.

[0008] The design disclosed in the present invention aims to provide an improved suction recovery catheter that solves the above-mentioned defects. Summary of the invention

[0009] Examples presented herein include devices and methods for removing acute blockages from a blood vessel during intravascular medical treatment. More specifically, the present disclosure relates to an actuated clot retrieval catheter system. An exemplary system for retrieving an embolus in a blood vessel may include a catheter, a first conductive wire, and an electronic circuit. The electronic circuit may provide a first current to the first conductive wire. A frame may be located near the distal end of the catheter and may be electrically connected to the first conductive wire. The frame may include a shape memory material that enables the frame or a portion thereof to transform from a martensite phase to an austenite phase when heated to a temperature above the austenite finish temperature of the material. At least a first portion of the frame may expand from a collapsed configuration to an expanded configuration when heated by a first current.

[0010] The shape memory material may have a transition temperature greater than about 37° C. In some examples, the shape memory material may have a transition temperature of about 45° C. to 55° C.

[0011] The system can include a thermoelectric cooling circuit in electrical communication with the frame. At least a first portion of the frame can be collapsible from an expanded configuration to a collapsed configuration when heat is removed by the thermoelectric cooling circuit.

[0012] At least a second portion of the frame is capable of collapsing from an expanded configuration to a collapsed configuration when heated.

[0013] The system may include a second conductive line in electrical communication with a second portion of the frame. The second conductive line may receive a second current from the electronic circuit.

[0014] The system may include a membrane cover disposed about the frame.

[0015] The frame can be located within the lumen of the catheter. In other examples, the frame extends from the distal end like a funnel to capture the obstruction.

[0016] The system may include a thermocouple in electrical communication with the frame. The thermocouple may assist in removing heat from at least a portion of the frame.

[0017] When at least the first portion of the frame is in the collapsed configuration, the shape memory material may be in the martensite phase.When at least the first portion of the frame is in the expanded configuration, the shape memory material may be in the austenite phase.

[0018] An exemplary method of retrieving an occlusive thrombus from a patient's blood vessel may include delivering a catheter including a frame to a target site. The frame may include a shape memory material. The method may include delivering a first current to the frame. The current flowing through the frame may heat the frame so that at least a first portion of the frame changes from a collapsed configuration to an expanded configuration. The method may include aspirating the occlusive thrombus into the frame. The catheter may be withdrawn from the patient together with the occlusive thrombus.

[0019] The shape memory material of the frame may have a transition temperature of about 45°C to 55°C.

[0020] The method may include deactivating the first current. By deactivating the first current, at least the first portion of the frame may cool to collapse at least the first portion of the frame over the occlusive thrombus.

[0021] The method may include cooling at least a first portion of the frame using a thermoelectric cooling circuit to collapse at least the first portion of the frame over the occlusive thrombus. The thermoelectric cooling circuit may include a Peltier sheet, thermoelectric wires, or the like.

[0022] The method may include delivering a second current to at least a second portion of the frame. The second current may generate heat through the resistance of the shape memory material, the heat causing at least the second portion of the frame to change from an expanded configuration to a collapsed configuration over the occlusive thrombus.

[0023] The method may include monitoring the temperature of the frame using a thermocouple in communication with the frame. The method may include deactivating the first current when the temperature is above a first temperature. This may ensure that the vessel is not damaged by excessive heating.

[0024] The frame can be located within the lumen of the catheter.In these examples, expanding at least a first portion of the frame from a collapsed configuration to an expanded configuration can result in an increase in the inner diameter of the catheter.

[0025] An exemplary method of manufacturing an actuated clot retrieval system may include heat setting a first shape memory material into a first frame having an expanded configuration. The method may include allowing the first shape memory material to cool and allowing the first frame to collapse into a collapsed configuration. The method may include connecting the first frame to a first end of a first conductive wire disposed within a catheter wall of a catheter. The method may include connecting a second end of the first conductive wire to an electronic circuit. The method may include applying a membrane to the first frame and a distal end of the catheter.

[0026] The method may include heat setting the second shape memory material into a second frame having a collapsed configuration. The method may include connecting the second frame to a first end of a second conductive wire disposed within the catheter wall. The method may include connecting a second end of the second conductive wire to an electronic circuit. The method may include applying a film to the second frame.

[0027] The first shape memory material and the second shape memory material can be different alloys, and the first frame and the second frame can be coaxial and connected to the distal end of the catheter. In other words, the second frame can be circumferentially positioned on the second frame so that the second frame can be closed on the first frame.

[0028] The first shape memory material and the second shape memory material may include the same alloy, and the first shape memory material and the second shape memory material may have different austenite finish temperatures.

[0029] The method may include providing a first conduit layer and disposing a first conductive wire on the first conduit layer. The method may include applying a second conduit layer on the first conductive wire and a first anchoring strut of the first frame. Connecting the first frame to the first end of the first conductive wire may include connecting the first anchoring strut to the first conductive wire before applying the second conduit layer.

[0030] The method may include wrapping the first frame with the ring to hold the first frame in the collapsed configuration. Applying the membrane to the first frame may include dipping the first frame and the ring into a membrane material and allowing the membrane material to cool. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other aspects of the present disclosure will be further discussed in conjunction with the following description of the accompanying drawings, in which the same reference numerals indicate the same structural elements and features in the various figures. The accompanying drawings are not necessarily drawn to scale, but instead, the emphasis is placed on illustrating the principles of the present disclosure. The accompanying drawings depict one or more specific implementations of the apparatus of the present invention by way of example only and not by way of limitation. It is expected that those skilled in the art can conceive and combine elements from the multiple drawings to better suit the needs of the user.

[0032] Figure 1A and Figure 1B is a side view of an exemplary actuated clot retrieval system according to aspects of the present disclosure;

[0033] Figure 1C and Figure 1D A method of delivering an exemplary actuated clot retrieval system to a target site within a vessel according to aspects of the present disclosure is shown;

[0034] Figure 2 is a cross-sectional view of an exemplary framework within a vessel according to aspects of the present disclosure;

[0035] FIG. 3A to FIG. 3C is an illustration of an exemplary design for providing current to a frame according to aspects of the present disclosure;

[0036] 4A to 4F is a side view of an exemplary frame design according to aspects of the present disclosure;

[0037] Figure 5A and Figure 5B is an illustration of an exemplary framework with opposing funnels according to aspects of the present disclosure;

[0038] Figure 6 is a cross-sectional view of an exemplary balloon-shaped frame according to aspects of the present disclosure;

[0039] Figure 7 is a side view of an exemplary actuated clot retrieval system having a retractable frame according to aspects of the present disclosure;

[0040] Fig. 8A and Figure 8B is a cross-sectional view of an exemplary design of a hole size for a dilation catheter according to aspects of the present disclosure;

[0041] 9A to 9F is an illustration of an exemplary attachment for connecting an anchor strut to a shape memory material according to aspects of the present disclosure;

[0042] Fig.10 is an illustration of an exemplary actuated clot retrieval system having a glove-shaped frame according to aspects of the present disclosure;

[0043] Fig.11 is a side view of an exemplary frame design according to aspects of the present disclosure;

[0044] Fig.12 is an illustration of an exemplary frame with a retractable distal spring according to aspects of the present disclosure;

[0045] Fig.13A and Fig. 13B A frame having braces of constant cross-sectional area according to aspects of the present disclosure is shown;

[0046] Fig.14A and Fig. 14B shows a frame with braces split into a V-shape for even heat / resistance flow according to aspects of the present disclosure;

[0047] Fig.15 is a perspective view of an exemplary frame having thermocouple wires connected to dissipative struts according to aspects of the present disclosure;

[0048] Figures 16 to 18B shows an exemplary design of a framework according to aspects of the present disclosure;

[0049] Fig.19 is a flow chart illustrating a method of retrieving an occlusive thrombus from a patient's blood vessel according to aspects of the present disclosure; and

[0050] Fig. 20 is a flow chart illustrating a method of making an exemplary actuated clot retrieval system according to aspects of the present disclosure. DETAILED DESCRIPTION

[0051] The solution disclosed herein relates to a clot retrieval catheter capable of providing local flow restriction / blocking via a modular distal frame. Flow restriction and large end design provide significantly greater suction efficiency. Such advantages are also particularly beneficial in stroke intervention surgery, where the vessels in the neurovascular bed are particularly small and circuitous, and thus customized axial and bending stiffness profiles can inhibit kinking and adhesion. The catheter can also be compatible with relatively low-profile entry sheaths and external catheters, so that the puncture wound in the patient's groin (in the case of femoral entry) can be easily and reliably closed. The catheter can also have internal and / or external low-friction lining features, as well as an external polymer sheath or film arranged around the support structure. The film can be an elastic material that encapsulates the frame or is mounted on the frame so that the frame can move independently of the film. The film can be tight-fitting or loose-fitting. A loose-fitting elastic film will be easier to open than a tight-fitting elastic film. The film can be sagging and made of a non-elastomeric material so that the force to open the film is low compared to the force of a tight-fitting elastic film. The membrane may be flipped to extend distally from a proximal position radially inward of the frame before returning to extend proximally radially outward from the frame, and wherein the inner and outer layers of the membrane are bonded or reflowed together at the proximal position or for the entire length of the membrane. The membrane may include an inner tube and an outer tube, the proximal and distal ends of the inner and outer tubes being bonded together or reflowed such that the two tubes form a sheath around the frame, with the frame free to move / expand within the sheath.

[0052] These improvements can lead to safer and faster access of catheters and other devices to complex areas to remove obstructions and reduce procedure time.While the present description is in many cases in the context of mechanical thrombectomy treatments, the systems and methods may also be applicable to other procedures and other body passages.

[0053] Access to various vessels within the vascular system, whether coronary, pulmonary or cerebral, involves well-known surgical procedures and the use of many conventional commercially available ancillary products. These products, such as angiographic materials, rotary hemostatic valves and guidewires, are widely used in laboratory and medical procedures. When these products are used in conjunction with the systems and methods described below, their function and exact composition are unknown in the relevant art.

[0054] The present systems and methods exploit the properties of shape memory materials to customize the distal dimensions of a clot retrieval device. Shape memory materials are those materials, such as alloys, that are deformable when cold and subsequently expand to a predetermined shape when heated. Once heat is removed from the material, the material can return to its collapsed, adaptable shape. This can be achieved by heating the shape memory material to above the austenite finish (AF) temperature. Below the AF temperature, the shape material leaves its martensite phase characterized by high elasticity, adaptability, and flexibility. Above the AF temperature, the shape material exists in its austenite phase characterized by a more rigid state. The shape memory material can be heat set to a predetermined shape above its AF temperature such that the material returns to the predetermined shape when the material is reheated to the AF temperature.

[0055] Various embodiments described herein may include a framework similar to a funnel sheath that, once expanded, can exert radial forces on the vasculature. Fluid can be drawn into the expanded funnel and subsequently into the catheter to capture thrombi within the funnel. The framework may include a membrane covering that directs the aspirate into the catheter. In other examples, the framework may be disposed within the lumen of the catheter. As the framework expands and collapses, the inner diameter of the catheter may increase and decrease to regulate the flow rate into the catheter.

[0056] The present disclosure provides a mechanism for heating a frame to its AF temperature to transform the frame into its austenite phase. One or more conductive leads may provide an electric current to the frame. The natural resistance of the shape memory material may then heat the frame to above the AF temperature. A thermocouple may also be provided to monitor the temperature of the frame so that the frame does not overheat and cause trauma to the surrounding vasculature. In some examples, a thermoelectric cooling loop (such as a Peltier chip) may be provided to transform the frame back into its martensite phase. The present disclosure provides various exemplary designs of the frame.

[0057] Various devices and methods for providing an actuated clot retrieval catheter are disclosed, examples of which will now be described with reference to the accompanying figures. Figure 1A and Figure 1B An illustration of an exemplary clot retrieval system 100 is provided. The system 100 may include a catheter 102 having a proximal end 104 proximal to a circuit housing 106 and a distal end 108. The catheter 102 may have an outer diameter small enough to allow the catheter 102 to be advanced through an external catheter, such as an access sheath. The system 100 may include a frame 110 proximate the distal end 108 of the catheter 102. The frame 110 may extend beyond the distal end 108 of the catheter, such as Figure 1A and Figure 1B In some examples, the frame 110 can be disposed within the lumen of the catheter 102, as will be described in more detail below. In other examples, the frame 110 can be positioned along the length of the catheter 102 so that the frame 110 can act as a closed "balloon", as will be described below with reference to Figure 6 described.

[0058] The frame 110 can be encapsulated in a reverse film, a double-layer sealing film or an overmolded film or an impregnated film. When the frame 110 is contained in an inner film layer and an outer film layer, the frame can have unimpeded movement. In the case of providing an overmolded film, there may be greater resistance due to the more discrete areas of the frame 110 stretch film material that may be required. It should be understood that when an electric current will flow through the frame 110, the frame may be insulated to accommodate the electric current. The film material can be used to insulate the frame 110. Therefore, the frame 110 acting as a resistor can generate heat under the current load.

[0059] The frame 110 can have an expanded configuration and a collapsed configuration. Figure 1A The funnel-shaped frame 110 is shown in an expanded configuration, while Figure 1B The same frame 110 is shown in a collapsed configuration. The frame 110 may include a shape memory material so that the frame 110 can be transformed from a collapsed configuration to an expanded configuration or vice versa when heated, and return to its previous configuration when cooled. The shape memory material of the frame 110 may include an alloy having a shape memory effect so that the material can be transformed from a martensite phase to an austenite phase. These materials may include, but are not limited to, Ni-Ti (Nitinol) alloys, Ni-Al (Nickel Aluminum) alloys, In-Ti (Indium Titanium) alloys, Ag-Cd (Silver Cadmium) alloys, Au-Cd (Gold Cadmium) alloys, Cu-Al-Ni (Copper Aluminum Nickel) alloys, Cu-Sn (Copper Tin) alloys, Cu-Zn (Copper Zinc) alloys, Mn-Cu (Manganese Copper) alloys, and similar alloys.

[0060] Shape memory materials enable devices to be manufactured so that once heated above the AF temperature, the device can be preset into a predetermined shape. Figure 1A and Figure 1B The exemplary funnel-shaped frame 110 may be provided in a collapsed configuration ( Figure 1B ). The frame 110 may then be heated to above the AF temperature of the shape memory material and subsequently formed into its final configuration ( Figure 1A ). At this stage, the frame 110 is in its austenite phase. Once the frame 110 is recooled to below the AF temperature of the material, the frame 110 can return to its unset shape. At this stage, the frame 110 is in its martensite phase and cooling can be easily achieved by conduction with the lead wires and / or thermocouple wires and subsequently through the jacket material and / or membrane material of the conduit 102 due to the low heat capacity of the frame 110.

[0061] Figure 1C and Figure 1DAn exemplary method of actuating a clot retrieval system 100 using the transformation properties of a shape memory material is provided. An actuated clot retrieval system 100 including a catheter 102 and a frame 110 can be advanced to a target site 20 in a vessel 30 containing a clot 40. This can be accomplished by advancing the system 100 through an external catheter 10, as shown. However, as will be described below, the catheter 102 and frame 110 can be advanced to the target site 10 without the need for an external catheter 10. Once the catheter 102 and frame 110 reach the target site 20, the frame 110 can be in its martensite phase characterized by the material's high elasticity, easy adaptability, and flexibility. This can enable the frame 110 to be easily advanced through a wound vessel 30. Once the frame 110 is at the target site 20, the frame 110 can be heated (described in more detail below) to enable the frame 110 to transform from the martensite phase to the austenite phase. Figure 1D In the example shown, the frame 110 is heat set into a funnel sheath in its austenite phase, such that when heated, the frame 110 expands into a funnel to exert a force on the vessel 30. The clot 40 can then be drawn into the frame 110 and removed from the target site 20. In some examples, the frame 110 can be actively cooled, such that the frame 110 collapses into its martensite phase to capture the clot 40. Alternatively, the frame 110 can be automatically cooled due to the low heat capacity of the frame 110.

[0062] Reference again Figure 1A and Figure 1B , various shape memory materials (including the above alloys) have different AF temperatures, allowing the system 100 to be customized for specific surgeries. In addition, materials processed to have a specific AF temperature can be reprocessed through a subsequent process involving heat treatment to reset the AF temperature to a desired range. The shape memory material can be selected or processed so that the AF temperature is higher than human blood (e.g., higher than 37°C) so that the frame 110 is not accidentally activated before reaching the intended activation location in the vessel. The AF temperature can be between 35°C and 200°C (e.g., between 37°C and 65°C, between 40°C and 60°C, etc.). The ideal AF temperature can be in the range of 45°C to 55°C. This can help ensure martensitic properties for a highly flexible delivery configuration while minimizing the energy required to heat the frame 110 to achieve expansion and rigidity properties.

[0063] As used herein, the term "about" or "approximately" for any numerical value or range indicates a suitable dimensional tolerance that allows a part or a collection of parts to function for its intended purpose. More specifically, "about" or "approximately" may refer to a range of ±10% of the value of the listed value, for example, "about 50°C" may refer to a range of values ​​from 45.001°C to 54.999°C.

[0064] The frame 110 may be heated by providing an electric current to the frame 110. The high resistance of the shape memory material (e.g., Nitinol) may cause the frame 110 to be heated in response to the electric current, and the heat in turn causes a transformation from the martensite phase to the austenite phase. The system 100 may include an electronic circuit 112 to provide the desired electric current to the frame 110. The electronic circuit 112 may be disposed within the circuit housing 106. The electronic circuit 112 may be activated using a switch 114. The electronic circuit 112 may feed a current of about 300 mA to about 1500 mA (e.g., about 500 mA to about 1000 mA) to the frame 110 using a power supply ranging from, for example, about 3 to 12 V, more preferably about 5 to 9 V. The electric current may be pulsed from 1 millisecond to 1000 milliseconds, more preferably from 100 milliseconds to 500 milliseconds, with the current interruption between 1 millisecond and 1000 milliseconds, more preferably from 1 millisecond to 100 milliseconds. The pulses allow the temperature of the frame to be maintained between a set temperature range, with the on portion of the pulse heating and the off portion of the pulse allowing the frame to cool so that the temperature is maintained between a certain range. The temperature can be monitored by a thermocouple so that if the temperature is out of range, the pulses can be changed; for example, a continuously fed current can be used to rapidly increase the temperature, and the pulses can be reduced to keep the temperature of the frame within the upper range.

[0065] One or more conductive wires 116 (eg, positive lead 118 and negative lead 120 ) may extend between electronic circuit 112 and frame 110 to provide electrical current to heat frame 110 . Figure 1A The cross-section A of FIG. 1 shows the positive lead 118 and the negative lead 120 attached to the frame 110. The conductive wire 116 can be embedded within the layers of the conduit 102 so that the wires are not exposed on the outer or inner surfaces of the conduit 102. This can enable the system 100 to be advanced into an external conduit without the wires restricting the movement of the conduit 102 through the external conduit. The conductive wire 116 can include copper or any other material suitable for providing electrical current to the frame 110.

[0066] The system 100 may include a thermocouple 122 connected to the frame 110 to monitor the temperature of the frame 110. If the frame 110 is heated above a certain temperature, the frame 110 may burn the surrounding vasculature. To this end, the thermocouple 122 may monitor the temperature of the frame 110 as it is heated by the current. If the frame 110 exceeds a certain temperature, such as 50° C., the thermocouple 122 may transmit this information to the electronic circuit 112 to deactivate the current provided to the frame 110. The thermocouple 122 may include a platinum or stainless steel wire that may be welded between the frame 110 (e.g., at the anchoring struts 206) and the conductive wire 116, wherein the electronic circuit 112 measures the resistivity difference between the shape memory material and the thermocouple wire to determine the temperature of the frame 110. This may be calibrated and may have a linear temperature relationship.

[0067] The system 100 may include a thermoelectric cooling loop 123 in electrical communication with the frame 110. The thermoelectric cooling loop 123 may include, for example, a Peltier sheet disposed proximate to the frame 110. As described above, when the frame 110 is cooled to below the AF temperature, the shape memory material of the frame may transform back into a conformable, flexible martensite phase. This may accomplish the capture of the clot 40 in the frame 110. Instead of allowing the shape memory material to cool naturally, the thermoelectric cooling loop 123 may extract heat from the frame 110 to cool the frame 110 more quickly.

[0068] The frame 110 is characterized in that a plurality of struts 124 can be formed into a closed cell 126, a ring or a wave pattern. A plurality of distal hoop or crown struts (which will be described below) can form the outer periphery of the frame opening 128. The frame 110 can have various shapes, including a low-profile circular end, an open funnel as shown, or other shapes described herein. A plurality of struts 124 can be enclosed in a membrane 130. The membrane 130 can provide a device for guiding fluid aspirates into the frame 110 and into the catheter 102. When the frame 110 is in a collapsed configuration, the membrane 130 can also maintain the position of the struts 124. Suitable membrane 130 materials can include elastic polyurethanes (such as Chronoprene, Chronosil, Chronoflex) with high elasticity and insulation and good tear resistance and other silicone and polyurethane polymers, etc. The membrane 130 can have a low hardness so that the membrane 130 can stretch when the frame 110 expands. For example, the film 130 may have a typical 00 range and a Shore hardness of Shore A0.1 to Shore A100 (e.g., Shore A40 to Shore A80). Because the film 130 encapsulates the frame 110 that may be intended to expand, the film 130 may also have an extensibility of, for example, 200% to 2200% (e.g., 400% to 800%).

[0069] The struts 124 may be coated with a film of a material having a high dielectric strength, such as parylene, to insulate the struts from blood (which is a conductor), for example, when the frame 110 is not fully enclosed or sealed by the film 130 .

[0070] Reference again Figure 1C and Figure 1D , the system 100 can be used in conjunction with the suction source 50. In many cases, the expanded frame 110 can seal with the wall of the vessel 30 to direct the suction to the distal end 108 of the catheter 102. In other words, the expanded frame 110 can also block flow and prevent undesired aspiration of blood proximal to the frame 110.

[0071] Figure 1C and Figure 1DThe system 100 is shown in which a catheter 102 for a framework 110 is inserted through an outer catheter 10. However, in some examples, an outer catheter 10 is not required. Instead, the catheter 102 for the framework 110 may be a catheter that needs to be inserted from a guide catheter ( Figure 1C or Figure 1D For example, the catheter 102 and frame 110 can be advanced away from the guide catheter because the system is highly flexible and self-actuated (e.g., the frame 110 can change from a closed configuration to an open configuration without unsheathing from the catheter). Thus, the guide catheter can reside, for example, in the internal carotid artery, and the catheter 102 and frame 110 can be extended entirely to the M1 or M2 vessels.

[0072] Figure 2 is a cross-sectional view of an exemplary funnel-shaped frame 110 in an expanded configuration. The length of the frame 110 may be longer or shorter than the length shown. For example, the length may be increased to provide a larger area of ​​contact with the vessel wall 35 or to increase the receiving space of the clot within the frame 110. The frame 110 may include a plurality of annular crowns 202 around the periphery of the frame 110. The annular crowns 202 may form the distal end 412 of the frame 110 and / or provide radial support at any other location along the length of the frame 110. The frame 110 may include one or more longitudinal struts 204 that may connect the peaks of the annular crowns 202. The annular crowns 202 and the longitudinal struts 204 may form cells 126 or openings. The cells 126 may be spaced apart to promote uniform expansion of the frame 110 and the membrane 130.

[0073] In some examples, the frame 110 does not include longitudinal struts 204, but rather the plurality of annular crowns 202 may be connected at each peak so that the cells 126 form a diamond-shaped grid structure. The uniform spacing of the diamond-shaped cells 126 may also promote uniform expansion of the frame 110 and the membrane 130. In other examples, the frame 110 does not include longitudinal struts 204, and the plurality of annular crowns 202 are not connected at the peaks. In these examples, the annular crowns 202 may instead be held in place by the membrane 130.

[0074] The shapes and configurations of the frame 110 described herein can be formed by laser cutting the design into a tube. After laser cutting the design, the frame 110 can be positioned into its desired configuration and heat set so that the frame 110 can return to the desired configuration when heated during surgery.

[0075] The frame 110 may include one or more anchoring struts 206 extending proximally. The conductive wires 116 may be connected to the one or more anchoring struts 206 to provide current to the frame 110. Figure 2 As shown, the film 130 may enclose at least a portion of the distal end 108 of the catheter 102 .

[0076] The frame 110 can be kept short to have a minimal path for current to travel (length and cross section of the struts 124, longer lengths and larger cross sections will have the greatest resistance) so that resistance is kept to a minimum so that the basket of the frame 110 can be quickly heated and expanded.

[0077] FIG. 3A to FIG. 3C An exemplary design for providing current to the frame 110 is shown. As described above, one or more of the struts 124 defining the structure of the frame 110 can be an anchoring strut 206 that is connected to the positive lead 118 or the negative lead 120 to receive current to heat the frame 110. The positive lead 118 and / or the negative lead 120 can extend through the structural layer of the catheter 102 and connect to the anchoring strut 206 within the structural layer. Embedding such an electrical connector within the catheter 102 can prevent the wire from separating from the frame 110 and is insulated from conductive media (such as blood). In other examples, the positive lead 118, the negative lead 120, and / or the anchoring strut 206 can be wrapped around the outer surface of the catheter 102 or within the inner cavity 302 of the catheter 102. The positive lead 118 and / or the negative lead 120 may extend longitudinally along the length of the catheter 102, or in a spiral, braided, interwoven, or other pattern as desired that may be used to improve the stiffness or flexibility of the catheter 102. The profile of the wire may be varied longitudinally to fine-tune the stiffness / flexibility. In some examples, the anchoring struts 206 may be pushed through openings formed in the catheter 102 wall.

[0078] Certain joints between the struts 124 may be connected to the insulating joint 304 so that current is not transferred from one side of the insulating joint 304 to the other side. This enables heat to be applied to the frame in a controlled pattern. Controlling the heat applied to different areas of the frame 110 enables certain parts of the frame to be transformed into the austenite phase while other parts are not transformed. In some examples, as described above, insulating certain parts of the frame 110 also enables the frame 110 to have different activation sequences. The first portion of the frame 110 may be configured to expand when receiving current, and the second portion of the frame may be configured to collapse when receiving current. This may enable the user to collapse the frame 110 by applying current to a portion of the frame 110 instead of waiting for the shape memory material to cool. Current may flow into one side of the frame 110 through the negative lead 120 and flow to the other side of the frame 110 in a uniform resistance path, where the current returns through the positive lead 118. For example, if the anchoring brace 206 of the frame 110 is connected to the V-shaped expansion brace of the frame 110, the anchoring brace 206 can be about twice the cross-sectional area of ​​each of the braces 124 forming the v-shaped expansion brace. This will allow for uniform flow of resistance between the braces. The various segments of the expansion frame can be separated by insulators, and the different segments can each have independent positive and negative lead sets.

[0079] 4A to 4F An exemplary design of frame 110 is shown. Figure 4A The frame 110 is shown with four anchor struts (i.e., anchor struts 206A, 206B, 206C, 206D). As described above, the anchor struts 206A, 206B, 206C, 206D can be embedded in the catheter 102 ( Figure 4A Each anchoring brace 206A, 206B, 206C, 206D may have an electrical connection 401 connected to different components of the system 100. In other words, the electrical connection 401 connected to the anchoring brace 206A, 206B, 206C, 206D may be a connection to the positive lead 118, the negative lead 120, the thermocouple 122, the thermoelectric cooling loop 123, or any combination thereof. For example, two of the anchoring braces 206A, 206B, 206C, 206D may be connected to the positive lead 118 and the negative lead 120 to provide current for heating the frame 110; and / or one of the anchoring braces 206A, 206B, 206C, 206D may be connected to the thermocouple 122; and / or one of the anchoring braces 206A, 206B, 206C, 206D may be connected to the thermoelectric cooling loop 123; and / or two anchoring braces may be connected to the positive lead 118, and two anchoring braces 206 may be connected to the negative lead 120; and / or any combination thereof. In some examples, two anchoring braces may be connected to the positive lead 118 to make the current flowing through the frame 110 more balanced using two negative return leads.

[0080] In some examples, two of the anchoring struts (e.g., anchoring struts 206A and 206C) may be connected to the positive lead 118 and the negative lead 120 for the first portion of the frame 110 (e.g., the first portion 111A); and two of the anchoring struts (e.g., anchoring struts 206B and 206D) may be connected to the positive lead 118 and the negative lead 120 for the second portion of the frame 110 (e.g., the second portion 111B). This may allow the first portion 111A of the frame 110 to have different activation characteristics than the second portion 111B of the frame 110. The first portion 111A of the frame 110 may be heat set to an expanded configuration. By providing an electric current and thereby generating heat through electrical resistance, the first portion 111A may be expanded during surgery. The second portion 111B of the frame 110 may be heat set to a collapsed configuration. By providing an electric current and thereby generating heat through electrical resistance, the second portion 111B may be collapsed during surgery. This enables a user of the system to advance the system 100 to the target site 20, direct a first current to the first portion 111A to expand the frame 110 and draw the clot 40 into the frame 110. The user may then direct a second current to the second portion 111B to collapse the frame 110 and capture the clot 40. As described above, each anchor strut 206A, 206B, 206C, 206D may have an electrical connection 401 to a different component of the system 100. For the example with the first portion 111A and the second portion 111B, this means that the two electrical connections 401 may include a second positive lead and a second negative lead, respectively, to heat one of the frame portions independently of the other, with each circuit being insulated from the other.

[0081] The first portion 111A and the second portion 111B of the frame 110 may include the same shape memory material, and each material may have the same AF temperature. In other examples, the two portions may include the same material, but have different AF temperatures. The first portion 111A and the second portion 111B may include different shape memory materials, which may also allow the portions to have different AF temperatures if desired. In an example with two portions with different AF temperatures, the AF temperature of one portion may be lower than the AF temperature of human blood (e.g., lower than 37° C.), so that it expands once it is delivered to the target site 20 and contacts the blood; the AF temperature of the other portion may be higher than 37° C., so that it collapses only when heated by an electric current. Conversely, the AF temperature of a portion may be lower than the AF temperature of human blood, so that it collapses when heated by blood.

[0082] The first portion 111A and the second portion 111B may be interconnected to form a unit 126 of the frame. When the first portion 111A and the second portion 111B of the frame 110 are intended to have different activation characteristics, this may be accomplished by using, for example, Figure 3CThe insulating joint 304 shown shields heat from one portion from heat from another portion. Instead of the first portion 111A and the second portion 111B being located at different locations on the frame 110, the first portion 111A and the second portion 111B may include two separate coaxial frames that are not interconnected. For example, Figure 2 The exemplary frame 110 shown in the figure may have a second frame disposed above the frame shown in the figure, which can be circumferentially wrapped around the inner frame. The outer frame (i.e., the outer portion) can be heat-set to a collapsed configuration, and the inner frame (i.e., the inner portion) can be heat-set to an expanded configuration. The inner frame can be expanded to receive the clot 40, and the outer frame can be activated to close, compress the inner frame and capture the clot 40. In these examples, the inner frame and the outer frame will interact. In some examples, some annular crowns 202 may have different activation characteristics than other annular crowns 202, some annular crowns expanding when heated and others collapsing when heated.

[0083] Figure 4B The frame 110 is shown with a split collar 402. A first side 404 of the split collar 402 can be in electrical communication with the positive lead 118, while a second side 406 of the split collar 402 can be in electrical communication with the negative lead 120. The split collar 402 can provide a means for conduit 102 (in Figure 4B The split collar 402 may be provided on a surface of the conduit 102 (not shown) that is locked to the frame 110. For example, the split collar 402 may be disposed within a structural layer of the conduit 102. In other examples, the split collar 402 may be placed on an outer surface of the conduit 102, and the positive lead 118 and / or the negative lead 120 may extend through a hole in the conduit 102 wall to connect to the split collar 402. The split collar 402 may also be disposed within the lumen 302 of the conduit 102. In other examples, the frame 110 may include a solid collar 408, such as Figure 4C As shown, it may be similar to split collar 402. In the case of solid collar 408, positive lead 118 and / or negative lead 120 may be connected directly to stay 124 so that the current flow is not excessively resisted by solid collar 408, thereby causing slow heating of the expansion frame.

[0084] Figure 4DA frame 110 is shown with a coiled collar 410. The coiled collar 410 may be similar to the open collar 402 and / or solid collar 408 above in that it may be disposed within an intermediate layer of the catheter 102, on an outer surface of the catheter 102, or within the lumen 302 of the catheter 102. The coiled collar 410 may provide pushability and flexibility while reducing the complexity of the construction to minimize the wall thickness required at the distal end 108 of the catheter 102. The coiled collar 410 may be formed by the lead 116, or may be integral with the frame 110. Insulated leads of highly conductive materials such as copper may be braided to provide good pushability for the catheter construction. Stainless steel may also be used for the leads. Although steel has a lower conductivity than copper, steel may provide better stiffness properties, and a larger diameter wire may be used to offset the lower conductivity while providing higher stiffness.

[0085] Figure 4E An exemplary strut 124 configuration of the frame 110 is shown. The axial force provided by the funnel-shaped frame 110 can be customized by changing the angle 414 (e.g., the crown peak 416) between the struts 124. Acute angles provide less radial force and require a smaller percentage of elongation at break of the membrane 130, while obtuse angles provide greater radial force and require a greater percentage of elongation at break of the membrane 130. Acute angles can be achieved by lengthening the struts 124 and / or increasing the number of crown peaks 416 of each annular crown 202. In addition, when the frame 110 is expanded, the crown peaks 416 can be enlarged (i.e., rounded) to increase resistance to microcracks and fractures. For another example, the crown peaks 416 can form a large rounded curve extending substantially in a semicircle from the proximal ends of adjacent struts 124. Such a large rounded semicircular profile will be atraumatic to the blood vessel.

[0086] like 4A to 4D As shown, the distal end 412 of the frame 110 can be radially tapered or curved inward to reduce trauma to the vessel wall 35. In other examples, the distal end 412 can be radially flared outward to improve apposition with the vessel wall 35. In some examples, the frame 110 may include a wing 418 extending proximally on the frame 110, such as Figure 4F By extending proximally, the wings 418 are less likely to pierce the vessel wall 35 if the frame 110 is advanced distally toward the target site 20. The wings 418 can extend outward beyond the other struts 124 of the frame 110 and further increase the radial force on the vessel wall 35. This configuration also allows the distal tip 412 to flare inward to reduce the possibility of trauma to the vessel wall 35, while also allowing the wings 418 to expand to contact the vessel wall 35 and form a fluid-tight seal in the vessel 30. As another example, the crown of the wings 418 can be connected to the proximal struts, as described below with reference to Figure 5A and Figure 5B described.

[0087] Figure 5A and 5B An exemplary frame 110 is shown having a distal portion 502 and a proximal portion 504. The distal portion 502 of the frame 110 can be similar to any of the frames 110 described herein. The proximal portion 504 can be opposite the distal portion 502 and toward the catheter hub ( Figure 5A or Figure 5B 100). The proximal portion 504 may have an expanded configuration and an open configuration, similar to the configuration described for any one of the above-mentioned frame 110 embodiments. In the collapsed configuration, the proximal portion 504 may rest on or adjacent to the distal end 108 of the catheter 102. Once opened to its expanded configuration, the proximal portion 504 may form a proximally facing funnel to offset blood pressure / blood flow and prevent unnecessary blood suction on the proximal side of the frame 110. The proximal portion 504 and / or the distal portion 502 may include a membrane 130. The proximal portion 504 and the distal portion 502 may be connected to a solid collar 408 or any other collar described herein. In some examples, as described above, the proximal portion 504 and the distal portion 502 may be connected to different conductive wires so that one portion can be opened or closed with a first current and one portion can be opened or closed with a second current. As another example, struts 124 may extend proximally from the proximal crown of the proximal portion to a second loop positioned proximal to the solid loop 408. Either or both of these loops may be segmented. Connecting the proximal peak of the proximal portion to the proximal loop may help reduce the likelihood of the frame snagging on an external guide sheath or a vessel side branch as it is retracted proximally.

[0088] Figure 6 A design of a system 100 is shown that enables a frame 110 to act as a closed balloon. The frame 110 can be positioned along the length of the catheter 102 near the distal end 108 of the catheter 102. Unlike many of the designs described herein, in this example, the frame 110 does not extend beyond the distal end 108 of the catheter 102. The frame 110 may include a fixed collar 602 at one end and a floating collar 604 at the other end. The fixed collar 602 may be connected to an outer surface or may be embedded in a structural layer of the catheter 102 so that it does not slide along the length of the catheter 102; conversely, the floating collar 604 may slide along the length of the catheter 102. A plurality of struts 124 may be connected to the two collars 602, 604 and extend between the two collars. In some examples, the struts 124 may be integral struts (e.g., Figure 6), while in other examples, the struts may be overlapping (e.g., a braided pattern). When an electric current is applied to the frame 110, the frame 110 may expand and the floating collar 604 may collapse toward the fixed collar 602. When the floating collar 604 collapses, the struts 124 expand and force the membrane 130 balloon to expand outward to form a seal against the vessel wall 35. When the shape memory material cools, the frame 110 may then collapse under the compressive force applied by the expanded elastomeric balloon. The frame 110 may float inside the balloon material, or the frame 110 may be encapsulated in the balloon material. In some examples, the membrane 130 may include a first seal 606 and a second seal 608 at the ends of the membrane 130. The first seal 606 and / or the second seal 608 may form a liquid-tight connection between the membrane 130 and the catheter 102. The first seal 606 and / or the second seal 608 can be permanently fixed to the catheter 102, and the membrane 130 can stretch as the struts 124 expand. In other examples, one of the first seal 606 and / or the second seal 608 can collapse with the floating collar 604. In these cases, the first seal 606 and / or the second seal 608 can be a gasket that can slide along the outer surface of the catheter 102, such as an O-ring.

[0089] Figure 7The design of the system 100 is shown, which enables the anchoring struts 206 to expand or collapse like a spring, thereby moving the position of the frame 110 along the catheter 102. The end of the catheter 102 proximal to the frame 110 may include a narrow segment 702. The anchoring struts 206 extending from the frame 110 may be coiled around the narrow segment 702. The anchoring struts 206 may be connected at one end to a floating collar 604 that can move along the length of the narrow segment 702. The opposite end of the anchoring struts 206 may be connected to a conductive wire 116 (e.g., a positive lead 118 or a negative lead 120). The anchoring struts 206 may be heat set to a collapsed configuration so that when the anchoring struts 206 are heated, they collapse to pull the frame 110 proximally along the catheter 102. The distal end 108 of the catheter 102 may include a catheter tip 704 having an outer diameter greater than the inner diameter of the floating collar 604. The catheter tip 704 can prevent the frame 110 from sliding distally out of the catheter 102. This mechanism enables the distal tip 412 of the frame 110 to align with the distal end 108 of the catheter 102 when the anchoring struts 206 are fully collapsed. In some examples, when fluid is drawn into the catheter 102, the anchoring struts 206 can collapse and the frame 110 can expand. Once the clot is pulled proximal to the distal end 108 of the catheter 102, the anchoring struts 206 can return to the extended configuration, and at the same time, the frame 110 can collapse around the clot to be removed from the vessel. The anchoring struts 206 and the frame 110 can be heated by the same current (i.e., by the same positive lead 118 and negative lead 120), or the anchoring struts 206 and the frame 110 can include separate electrical connections so that they can be heated independently. The distal end 412 can be advanced in a collapsed configuration by activating the anchor struts 206 acting as linear motion actuators so that the tip 412 is closer to the clot, and the tip 412 can be actuated to seal the vessel prior to aspiration.

[0090] In an alternative embodiment, the distal end 108 of the catheter 102 itself may instead be actuated by a spring mechanism. For example, the catheter 102 may include a flexible portion that includes a shape memory material disposed therein. When the shape memory material in the catheter 102 expands with heat, the distal end 108 of the catheter 102 may extend through the funnel formed by the frame 110 and toward the clot.

[0091] FIG. 8A to FIG. 8BThe design of the system 100 that enables the frame 110 to adjust the hole size of the catheter 102 is shown. The frame 110 can extend from the distal end 108 of the catheter 102 (the catheter not shown in the figure) to form the most distal part of the catheter 102. When the catheter 102 reaches the clot 40, the frame 110 can be expanded to increase the hole size of the catheter 102, and thus increase the flow into the catheter 102. This is particularly advantageous for larger or harder blood clots. For example, when the catheter 102 aspirates the clot, if the clot resists being pulled into the catheter, the operator can provide an electric current to the frame 110 to increase the flow into the catheter 102. The frame 110 can be a laser cut mesh design, a shape setting wire design, a wire braid design, etc. As described above, the frame 110 can be covered with a septum 130. The frame 110 can also be designed to expand over the entire length of the catheter 102.

[0092] In some examples, instead of extending from the catheter 102, the frame 110 can be positioned within the lumen 302 of the catheter 102. In a similar manner, when the frame 110 is expanded within the lumen 302, the pore size of the catheter 102 can increase to regulate flow.

[0093] 9A to 9F An exemplary design of an anchoring strut 206 is shown for attaching the conductive wire 116 to the frame 110. The conductive wire 116 may be connected to the anchoring strut 206 by a variety of mechanical means. Fig. 9A A mechanical connector 802 is shown that includes a "T" connector at one end and a hook at the other end that grabs and holds the "T" connector. Fig. 9B Shown is a coiled connector 804. A third material may be coiled over the conductive wire 116 and the anchoring strut 206 to create an electrical connection. Fig. 9C A mechanical crimp 806 is shown. The crimp 806 may include a third material that crimps the conductive wire 116 at one end and the anchor strut 206 at another end. Fig.9D A fork-shaped crimp 808 is shown. One end of the conductive wire 116 or anchoring strut 206 may include a fork that may be crimped onto the other end of the connector. Fig.9E An alternative fork-shaped crimp 810 includes teeth 812 that may help grip the material between the forks. Fig.9F A heat collapse method of bonding the conductive wire 116 and the anchoring strut 206 is shown. Other examples for connecting the conductive wire 116 to the anchoring strut 206 include, but are not limited to, overmolding, soldering, adhering, or welding the two components. Adhesives for adhering the conductive wire 116 to the shape memory material may include cyanoacrylates and epoxies. Welding methods for bonding the conductive wire 116 to the shape memory material include, for example, laser welding, plasma welding, tungsten inert gas (TIG) welding, and the like.

[0094] Fig.10 An exemplary system 100 is shown with a frame 110 that opens like a glove. As can be seen, it is not necessary for the frame to include multiple cells 126. The frame 110 may alternatively include a simple ring of struts 124 that can open like a glove when heated. Fig.10 It is also shown that in some examples, the leads 118, 120 and / or anchoring struts 206 can be spiraled within the structural layers of the catheter 102, as shown in cross-sectional view B. Spiraling the anchoring struts 206 can increase the length of the shape memory material and thus increase its resistance, which can increase the amount of heat provided to the frame 110. As another example, to save energy, the anchoring struts 206 can be kept short and the leads can be constructed straight to reduce the effects of the inductance from the coil. In another embodiment, the frame 110 can be provided as a plurality of simple loops, each of which is heated independently of a single lead pair or independently of a group of lead pairs.

[0095] Fig.11 The frame 110 is shown with the distal tip 412 in a slightly inwardly rotated expanded configuration. The radially inward rotation of the distal tip 412 can create an atraumatic profile if the user accidentally pushes the device distally during use. This feature can also help grasp the fibrin-rich clot 40 for safe extraction from the vessel 30.

[0096] Fig.12 A frame 110 is shown with a distal spring 1202. The distal spring 1202 can collapse when heated. The collapsed distal spring can deform a distal collar membrane 1204, which expands outwardly to form a funnel shape by inversion. The distal collar membrane 1204 can include a harder material than the other membranes 130 described above, so that the distal collar membrane 1204 can expand radially when collapsed with the distal spring 1202. The distal collar 1204 can be a composite of a braid and a membrane or a braid and a fine mesh, the braid acting as a reinforcing material to facilitate inversion.

[0097] Fig.13A and Fig. 13B 1 shows a frame 110 having a brace 124 having a constant cross-sectional area 1302. The constant cross-sectional area 1302 allows for a uniform flow of current throughout the frame 110. Fig. 13B As shown, the exemplary design also allows the frame 110 to decrease slightly in length as the frame 110 transitions from the closed configuration to the open configuration. In the closed configuration, the frame 110 may have a first length 1304, and when current is provided and heat is generated through resistance, the frame 110 may open like a funnel and have a shorter second length 1306.

[0098] Fig.14A and Fig. 14BA frame 110 is shown with the struts 124 split into a V-shape for uniform heat / resistance flow. The frame 110 may also include dissipation struts 1402 positioned at the crown peaks 416, which may remove heat from the struts 124 (e.g., to allow the struts 124 to cool) and also provide support for the membrane 130 cover. The design may also allow the frame 110 to decrease slightly in length as the frame 110 transitions from a closed configuration to an open configuration, as described above with reference to Fig.13A and Fig. 13B described.

[0099] Fig.15 1 is a perspective view of an exemplary frame 110 with a thermocouple 122, which is a wire connected to a dissipating stay 1402. The thermocouple 122 wire may include a material such as platinum or stainless steel that can be attached to the frame 110 at an attachment 1502. The attachment 1502 may include a weld or an adhesive. The thermocouple 122 wire may be in electrical communication with the electronic circuit 112, and the electronic circuit 112 may measure the resistivity difference between the frame 110 material and the thermocouple 122 to determine the temperature of the frame 110. This may be calibrated and may have a linear temperature relationship.

[0100] Figures 16 to 18B An exemplary design of frame 110 is shown. Fig.16 An exemplary frame 110 without collars (e.g., neither split collars 402 nor solid collars 408) is shown. The first anchoring struts 206A and the second anchoring struts 206B can extend from the frame 110 having a single annular crown 202. The single annular crown 202 can be formed by the membrane 130 ( Fig.16 ) held in place.

[0101] Fig.17A and Fig. 17B An exemplary frame 110 having an open collar 402 is shown. The distal end 412 of the frame 110 can lead to four different points (e.g., points 1702, 1704, 1706, 1708), such as Fig. 17B The frame 110 may include a membrane 130 to encapsulate the distal end 412 of the frame 110 and connect the points 1702, 1704, 1706, 1708 into a circular funnel shape.

[0102] Fig.18A and Fig.18B An exemplary frame 110 having a plurality of distal points 1802 is shown. The frame 110 may include a membrane 130 to encapsulate the distal end 412 of the frame 110 and connect the plurality of distal points 1802 into a circular funnel shape, such as Fig.18B shown in end view.

[0103] Fig.19is a flow chart illustrating a method of retrieving an occlusive thrombus from a patient's blood vessel. As will be appreciated, Fig.19 The method steps in can be implemented by any of the exemplary devices described herein or by similar devices. Fig.19 In step 1905, a catheter can be delivered to a target site, as described in the method 1900 outlined in the accompanying drawings. The catheter can be advanced, for example, through an external catheter or an access sheath. The catheter can include a frame made of a shape memory material. The frame can have a funnel shape, can be disposed within the lumen of the catheter, can be disposed along the length of the catheter, or can have any other shape described herein.

[0104] In step 1910, method 1900 may include delivering a first current to the frame. The first current may be delivered via a conductive wire connecting the frame to the electronic circuit. A user may activate the electronic circuit outside the patient's body.

[0105] In step 1915, method 1900 may include heating the frame to change at least a first portion of the frame from a collapsed configuration to an expanded configuration. When current flows through the frame, the frame heating is caused by the resistance of the shape memory material. At least the first portion of the frame means that the entire frame can be expanded, but it is not necessary for the entire frame to expand. As described above, the frame may have multiple portions with different transition characteristics. For example, a first portion of the frame may be heated to expand while a second portion is not heated. The second portion may be heated, for example, in a subsequent step to capture a thrombus. The shape memory funnel frame can be limited in expansion by an electrically actuated member, so that removing the current allows the restraining member to release and the shape memory material to expand due to the heat of the blood.

[0106] At step 1920, method 1900 can include aspirating the occlusive thrombus into the frame. The aspirate can be directed into the catheter through the frame, which can include a membrane covering that directs fluid.

[0107] At step 1920, method 1900 may include withdrawing the catheter with the occlusive thrombus from the patient. In the case where the thrombus is captured within the frame, the thrombus can be pulled out of the patient's vasculature without having to worry about the thrombus being dislodged from the catheter due to poor capture.

[0108] Method 1900 may end after step 1925. In other embodiments, additional steps according to the above examples may be performed. For example, method 1900 may include deactivating the first current to cool the at least first portion of the frame. Cooling the shape memory material may cause the at least first portion to collapse on the occlusive thrombus to improve capture of the thrombus for removal.

[0109] In some examples, method 1900 may include delivering a second current to at least a second portion of the framework. The second portion may have a different transformation characteristic than the first portion. For example, the second portion may be preset to a collapsed configuration in its austenite phase, meaning that once heated, it may collapse on the thrombus. Thus, method 1900 may include heating the second portion of the framework via the second current so that the second portion of the framework changes from an expanded configuration to a collapsed configuration and occurs on an occlusive thrombus.

[0110] The method 1900 may also include cooling at least a first portion of the frame with a thermoelectric cooling circuit to cause at least the first portion of the frame to collapse over the occlusive thrombus. A thermoelectric cooling circuit (such as a Peltier chip) may extract heat from the system. Using this effect, the thermoelectric cooling circuit may cause at least the first portion of the frame to cool and collapse faster around the occlusive thrombus.

[0111] The method 1900 may include delivering the current in a series of pulses in order to maintain a stable frame temperature, and the electronic circuit may monitor the temperature and adjust the pulse duration and / or length accordingly.

[0112] The method 1900 may also include monitoring the temperature of the frame with a thermocouple. In some examples, the thermocouple may monitor to determine if the frame exceeds a certain temperature (eg, 50° C.) and deactivate the first current if the frame exceeds the temperature.

[0113] Fig. 20 is a flow chart illustrating a method of manufacturing an exemplary actuated clot retrieval system. As will be appreciated, Fig. 20 The method steps in can be implemented by any of the exemplary devices described herein or by similar devices. Fig. 20 In the method 2000 summarized, a first shape memory material may be heat set into a first frame having an expanded configuration in step 2005. As described throughout this disclosure, heat setting the shape memory material may include heating the frame above its AF temperature, forming the frame into a desired shape, and then cooling the frame.

[0114] In step 2010, method 2000 may include allowing the first shape memory material to cool and allowing the frame to collapse into a collapsed configuration. Once cooled, the frame is more flexible and conformable because it is in its martensite phase. The collapsed frame may be restored to its predetermined shape by reheating the frame to above the AF temperature.

[0115] At step 2015, method 2000 may include coupling a first frame to a wall disposed on a conduit (eg, Figure 3BThe frame may have electrical connections, for example, to the positive lead and the negative lead to provide current to heat the frame. Such electrical connections may be made within the structural layers of the conduit itself, thereby protecting the connection from accidental separation. The first conduit layer (e.g., Figure 3B The first conduit layer (e.g., the first layer 308 in the conduit layer) and then the first conductive wire is placed on the first conduit layer to make electrical connections within the construction layer. At this point, the frame can be attached to the conductive wire, for example, by attaching the conductive wire to the anchoring struts of the frame. A second conduit layer (e.g., Figure 3B A second layer 310 in is applied over the first conductive wire and the first anchoring strut to encapsulate the connection within the structural layer of the catheter.

[0116] In step 2020, method 2000 may include connecting the second end of the first conductive wire to an electronic circuit. The electronic circuit may be located distally of the frame. The electronic circuit may be disposed within a housing that includes a switch for activating the current.

[0117] In step 2025, method 2000 may include applying a film to the first frame and the distal end of the catheter. The film can be applied by a variety of methods. One method is to apply a thin base material to an impregnation mandrel with the catheter in place, then injection mold an intermediate layer with a collapsed frame held in place by an outer mold, and the final top layer can be applied using a second outer mold or by a final dip coating method. In some examples, a preformed ring of a material that will not form a bond with the encapsulating film can be used to hold the frame in a collapsed position. After encapsulating the frame with enough material by an impregnation or molding process, the preformed ring can be removed before the final impregnation or molding process to fill the gap left by the ring. Alternatively, a preformed ring of the same material can be used to avoid the necessity of removing the ring.

[0118] Method 2000 may end after step 2025. In other embodiments, additional steps according to the above examples may be performed. For example, method 2000 may include heat setting the second shape memory material into a second frame having a collapsed configuration. The second frame may be heat set in a manner similar to the first frame described above. The second frame may be heat set into a collapsed configuration so that once heated, the second frame may return to the collapsed configuration (e.g., to capture a clot). Method 2000 may include allowing the second shape memory material to cool, and then connecting the second frame to the first end of a second conductive wire disposed within the catheter wall. Method 2000 may include connecting the second end of the second conductive wire to an electronic circuit so that the second frame may receive an electric current. The film may be applied to the second frame in a manner similar to the method described for the first frame. The first shape memory material and the second shape memory material may be the same alloy or may be different alloys. Providing different alloys may enable the two frames to have different transformation characteristics (e.g., they may transform from a martensite phase to an austenite phase at different temperatures). The first frame and the second frame may be coaxial and connected to the distal end of the catheter. In this way, the first frame expands when heated and the second frame can collapse over the first frame to capture the clot when heated.

[0119] The descriptions contained herein are examples of embodiments of the present disclosure and are not intended to limit the scope of the present disclosure in any way. As described herein, the present disclosure contemplates many variations and modifications of the suction device, including the use of alternative geometries of structural elements, combining shapes and structural elements from various exemplary embodiments, the use of alternative materials, etc. Such modifications will be apparent to one of ordinary skill in the art to which the present disclosure relates and are intended to be within the scope of the appended claims.

Claims

1. A system (100) for retrieving an embolus in a blood vessel (30), the system (100) comprising: A catheter (102); a first conductive line (116, 401); A second conductive line (116, 401); an electronic circuit (112), the electronic circuit (112) providing a first current to the first conductive line (116, 401) and providing a second current to the second conductive line (116, 401); a frame (110) in electrical communication with the first conductive wire (116, 401) and the second conductive wire (116, 401) and comprising a shape memory material, the frame (110) comprising at least a first portion and a second portion, the first portion being capable of expanding from a collapsed configuration to an expanded configuration when heated by the first current, and the second portion being capable of collapsing from an open configuration to a collapsed configuration when heated by the second current; and An insulating joint connects the first portion of the frame to the second portion of the frame such that the first current does not reach the second portion of the frame.

2. The system of claim 1, wherein the shape memory material has a transition temperature above 37°C.

3. The system of claim 1, wherein the shape memory material has a transition temperature of 45°C to 55°C.

4. The system according to claim 1 further includes a thermoelectric cooling circuit (123) electrically connected to the frame (110), wherein at least a first portion of the frame (110) is capable of collapsing from the expanded configuration to the collapsed configuration after heat is removed by the thermoelectric cooling circuit (123).

5. The system of claim 1, further comprising a membrane cover disposed around the frame (110).

6. The system of claim 1, wherein the frame (110) is disposed within a lumen (302) of the catheter (102).

7. The system of claim 1, further comprising a thermocouple (122, 1502) in electrical communication with the frame (110).

8. The system of claim 1, wherein: When the first portion of the frame (110) is in the collapsed configuration, the shape memory material is in a martensite phase; and When the first portion of the frame (110) is in the expanded configuration, the shape memory material is in an austenite phase.

9. A method of manufacturing an actuated clot retrieval system (100), the method comprising: heat setting the first shape memory material into a first frame (110, 111A) having an expanded configuration; allowing the first shape memory material to cool and allowing the first frame (110, 111A) to collapse into a collapsed configuration; Connecting the first frame (110, 111A) to a first end of a first conductive wire (116, 401) disposed within a conduit wall (306) of a conduit (102); Connecting the second end of the first conductive line (116, 401) to an electronic circuit (112); applying a film to the first frame (110, 111A) and the distal end of the catheter, The method further comprises: heat setting a second shape memory material into a second frame (110, 111B) coaxial with the first frame and having a collapsed configuration so that the second frame (110, 111B) can collapse onto the first frame (110, 111A) when heated to capture the clot; allowing the second shape memory material to cool; connecting the second frame (110, 111B) to a first end of a second conductive wire (116, 401) disposed within the conduit wall (306); connecting a second end of the second conductive line (116, 401) to the electronic circuit (112); and The film is applied to the second frame (110, 111B).

10. The method according to claim 9, wherein: The first shape memory material and the second shape memory material are different alloys; and The first frame (110, 111A) and the second frame (110, 111B) are connected to the distal end of the catheter.

11. The method according to claim 9, wherein: The first shape memory material and the second shape memory material comprise the same alloy; and The first shape memory material and the second shape memory material have different austenite finish temperatures.

12. The method according to claim 9, further comprising: providing a first conduit layer (308); Disposing the first conductive line (116, 401) on the first conduit layer (308); and applying a second conduit layer (310) over the first conductive wire (116, 401) and the first anchoring struts of the first frame (110, 111A), Wherein connecting the first frame (110, 111A) to the first end of the first conductive wire (116, 401) includes connecting the first anchoring strut to the first conductive wire (116, 401) before applying the second conduit layer (310).

13. The method of claim 9, further comprising wrapping the first frame (110, 111A) with a ring to maintain the first frame (110, 111A) in the collapsed configuration; Wherein applying the film to the first frame (110, 111A) comprises: dipping the first frame (110, 111A) and the ring into a membrane material; and The film material was allowed to cool.

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