Expandable multilayer electrode element for thrombectomy - Patent Application 20070122997

Abstract

The device (20) includes one or more longitudinal elements (28a, 28b, 30, 60) configured to pass through a sheath (22) within a subject's body and one or more expandable multi-layer electrode elements (24) coupled to the longitudinal elements. The electrode elements are configured to advance to a thrombus within the body while collapsing within the sheath and to expand distally into the sheath following advancement to the thrombus. Each of the electrode elements includes one or more reference electrodes (34) and one or more active electrodes (36) configured to attract the thrombus upon application of a voltage between the active and reference electrodes following expansion of the electrode element. Other embodiments are also described.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the benefit of U.S. Provisional Application No. 63 / 078,920, filed on September 16, 2020, entitled "Expandable electrode elements for thrombectomy procedures", the disclosure of which is incorporated herein by reference.

[0002] (Technical Field) The present invention relates to the field of medical devices, particularly devices for thrombectomy.

Background Art

[0003] In U.S. Patent No. 10,028,782 to Orion, the disclosure of which is incorporated herein by reference, a flexible catheter device is described that is introduced into a body passageway and from which fluid can be withdrawn or introduced. This device includes electrodes configured to apply an electrical signal within the body passageway for thrombolysis and / or thrombectomy, where one of the electrodes is designed to contact thrombus material to remove or dissolve it, and the electrical voltage signal is a monopolar pulsed voltage signal.

[0004] In U.S. Patent Application Publication No. 2018 / 0116717 to Taff et al., the disclosure of which is incorporated herein by reference, a device for removing thrombus from a subject's body is described. This device includes a first electrode made of a first conductive metal, a second electrode made of a second conductive metal different from the first conductive metal, and a voltage source configured to apply a positive monopolar voltage between the first electrode and the second electrode while the first electrode is in contact with the thrombus and the second electrode is within the subject's body.

[0005] U.S. Patent Application Publication 2019 / 0262069 to Taff et al., the disclosure of which is incorporated herein by reference, describes an electrical insulating tube configured to be inserted into the body of a subject, having a distal end having a circumferential wall shaped to define one or more small holes; an outer electrode positioned above the distal end of the electrical insulating tube and configured to be at least partially located within a thrombus when the electrical insulating tube is in the body; and an inner electrode configured to be located within the tube on the opposite side of the holes, while the outer electrode is at least partially located within the thrombus. When a positive voltage is applied between the outer electrode and the inner electrode to cause a current to flow through the holes, the outer electrode is configured to attract the thrombus while the outer electrode is at least partially within the thrombus and the inner electrode is on the opposite side of the holes.

[0006] The disclosure incorporated herein by reference in U.S. Patent Application Publication 2021 / 0186540 to Taff et al. describes an apparatus including a tube. The tube includes a proximity hub configured to advance into a occlusion and to connect to a suction applying device such that, following the advance of the tube into the occlusion, an attractive force generated by the suction applying device is applied to the occlusion through the tube. The apparatus further includes a control element including first and second conductive circumferential portions configured to pass through the tube. The apparatus further includes first and second conductive elements configured to connect the first and second conductive circumferential portions to the respective terminals of a power supply. The first conductive circumferential portion is configured to attract the occlusion when a voltage is applied between the first and second conductive circumferential portions by the power supply via the first and second conductive elements, and is configured such that the occlusion is fixed to the control element while an attractive force is applied to the occlusion.

[0007] In the international patent application publication WO / 2019 / 243992 to Taff et al., the disclosure of which is incorporated herein by reference, a device for removing an occlusion from the body of a subject is described. The device comprises a reference electrode configured for insertion into the body; an electrically insulating element covering the reference electrode and shaped to define a gap that exposes a portion of the reference electrode; an active electrode covering the electrically insulating element; and a conductive element passing through the reference electrode and electrically connected to the active electrode, the conductive element being configured to electrically connect the active electrode to a power source so that the application of a voltage between the active electrode and the reference electrode by the power source attracts the active electrode to the occlusion.

[0008] The disclosure incorporated herein by reference in the international patent application publication WO / 2020 / 174326 to Taff et al. describes a device for treating an occlusion in the body of a subject, comprising a tube configured for insertion into the body and shaped to define a first lumen and a second lumen having a distal opening. The device further comprises a pair of electrodes configured to apply a current to the occlusion when a voltage is applied between the electrodes, the pair of electrodes comprising an outer electrode wrapped around the tube and an inner electrode configured to pass through the first lumen. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] U.S. Patent No. 10,028,782 [Patent Document 2] U.S. Patent Application Publication No. 2018 / 0116717 [Patent Document 3] U.S. Patent Application Publication No. 2019 / 0262069 [Patent Document 4] U.S. Patent Application Publication No. 2021 / 0186540 [Patent Document 5] International Patent Application Publication WO / 2019 / 243992 [Patent Document 6] International Patent Application Publication WO / 2020 / 174326 [Overview of the Initiative]

[0010] According to some embodiments of the present invention, a device is provided comprising one or more longitudinal elements configured to pass through a sheath within the body of a subject, and one or more expandable multilayer electrode elements coupled to the longitudinal elements. The electrode elements are configured to advance toward a thrombus in the body while being compressed within the sheath, and to expand distally toward the sheath following their advance toward the thrombus. Each electrode element includes one or more reference electrodes and one or more active electrodes configured to attract a thrombus when a voltage is applied between the active electrode and the reference electrode following the expansion of the electrode element.

[0011] In some embodiments, the apparatus further includes a sheath.

[0012] In some embodiments, the longitudinal elements include proximal coupled longitudinal elements coupled to the proximal ends of each electrode element.

[0013] In some embodiments, the longitudinal elements include distally coupled longitudinal elements connected to the distal ends of each electrode element.

[0014] In some embodiments, the distally coupled longitudinal element includes a longitudinal element active electrode, a longitudinal element reference electrode positioned inside the longitudinal element active electrode, and an electrical insulating element positioned between the longitudinal element reference electrode and the longitudinal element active electrode.

[0015] In some embodiments, the distal coupling longitudinal element extends distally to the electrode element.

[0016] In some embodiments, the electrode element is extended to define one or more loops.

[0017] In some embodiments, the apparatus further includes distal electrode elements disposed at each distal end of the loops, the distal electrode elements including a distal active electrode, a distal reference electrode disposed inside the distal active electrode, and a distal electrical insulation element disposed between the distal reference electrode and the distal active electrode.

[0018] In some embodiments, the loop includes a proximal set of one or more proximal loops and a distal set of one or more distal loops coupled to each distal end of the proximal loops, the distal set having a maximum width smaller than that of the proximal set.

[0019] In some embodiments, at least one of the electrode elements has a sinusoidal shape when expanded.

[0020] In some embodiments, at least one of the electrode elements has a spiral shape when expanded.

[0021] In some embodiments, the electrode elements are configured to expand to define a shape having a width that decreases in the distal direction along the distal portion of the shape.

[0022] In some embodiments, each of the electrode elements includes a multilayer strip.

[0023] In some embodiments, the reference layer of the strip includes a reference electrode. One or more active layers of the strip include active electrodes, and the strip further includes one or more insulating layers that electrically insulate the reference layer from the active layers.

[0024] In some embodiments, the active layer consists of a single active layer, and the insulating layer consists of a single insulating layer disposed between the reference layer and the active layer.

[0025] In some embodiments, the active layer includes a first active layer and a second active layer located on the opposite side of the reference layer, and the insulating layer includes a first insulating layer located between the first active layer and the reference layer, and a second insulating layer located between the second active layer and the reference layer.

[0026] In some embodiments, each active layer is shaped to define one or more outer gaps, and each insulating layer is shaped to define one or more inner gaps aligned with the outer gaps.

[0027] In some embodiments, at least one of the insulating layers is narrower than (i) one adjacent reference layer or (ii) one adjacent active layer.

[0028] In some embodiments, the strip includes a substrate layer and one or more electrode layers attached to the substrate layer, each of which includes one reference electrode and one active electrode.

[0029] In some embodiments, one of each of the reference electrodes and one of each of the active electrodes protrude from each other.

[0030] In some embodiments, each electrode element includes a core containing a reference electrode, an electrical insulating layer wound around the core, and an active layer wound around the electrical insulating layer.

[0031] In some embodiments, the active layer is shaped to define one or more outer gaps, and the electrical insulating layer is shaped to define one or more inner gaps that are at least partially aligned with the outer gaps.

[0032] According to some embodiments of the present invention, a device is further provided comprising one or more expandable electrode elements configured to advance toward a thrombus in the body of a subject while being compressed within a sheath within the body, and to expand distally relative to the sheath to define one or more loops following the advance toward the thrombus. The device further comprises conductive longitudinal elements coupled to the distal end of each electrode element and configured to pass through the sheath. Each electrode element comprises one or more active electrodes configured to attract a thrombus when a voltage is applied between the active electrode and the longitudinal element following the expansion of the electrode element.

[0033] Furthermore, according to some embodiments of the present invention, a method is provided that includes the steps of: inserting a sheath into the body of a subject; advancing one or more expandable multilayer electrode elements into a thrombus in the body while collapsing them inside the sheath, each electrode element comprising one or more reference electrodes and one or more active electrodes; expanding the electrode elements distally into the sheath following their advance into the thrombus; and, following the expansion of the electrode elements, applying a voltage between the active electrode and the reference electrode to attract the thrombus to the active electrode.

[0034] In some embodiments, the method further includes the step of twisting the electrode element around the thrombus by rotating one or more longitudinal elements coupled to the electrode element and passing through a sheath, following the expansion of the electrode element.

[0035] In some embodiments, the longitudinal element is coupled to the distal end of each electrode element, and the longitudinal element includes a longitudinal element active electrode and a longitudinal element reference electrode positioned inside the longitudinal element active electrode, the method further includes the step of applying a voltage between the longitudinal element active electrode and the longitudinal element reference electrode.

[0036] In some embodiments, the distal electrode element is located at the distal end of each loop, and the distal electrode element includes a distal active electrode and a distal reference electrode located inside the distal active electrode, and the method further includes the step of applying a voltage between the distal active electrode and the distal reference electrode.

[0037] According to some embodiments of the present invention, a method is provided which includes the step of inserting a sheath into the body of a subject. The method further includes advancing one or more expandable electrode elements into a thrombus in the body, with the expandable electrode elements being compressed inside the sheath, each of the electrode elements comprising one or more active electrodes, and a conductive longitudinal element coupled to the distal end of each electrode element. The method further includes expanding the electrode elements distally to the sheath to form one or more loops following their advance into the thrombus, and attracting the thrombus to the active electrodes by applying a voltage between the active electrodes and the longitudinal elements, following the expansion of the electrode elements.

[0038] The present invention will be better understood from the following detailed description relating to embodiments used in conjunction with the drawings. [Brief explanation of the drawing]

[0039] [Figure 1] This is a schematic diagram of an apparatus for removing blood clots from a subject's body, according to several embodiments of the present invention. [Figure 2A] This is a cross-sectional view through an electrode element according to a different embodiment of the present invention. [Figure 2B] This is a cross-sectional view through an electrode element according to a different embodiment of the present invention. [Figure 2C] This is a cross-sectional view through an electrode element according to a different embodiment of the present invention. [Figure 2D] This is a cross-sectional view through an electrode element according to a different embodiment of the present invention. [Figure 2E] This is a schematic diagram of an electrode element including a multilayer strip according to some embodiments of the present invention. [Figure 2F]This is a schematic cross-sectional view through an electrode element according to several embodiments of the present invention. [Figure 3] These are schematic diagrams of devices for removing blood clots from a subject's body according to different embodiments of the present invention. [Figure 4] These are schematic diagrams of devices for removing blood clots from a subject's body according to different embodiments of the present invention. [Figure 5] These are schematic diagrams of devices for removing blood clots from a subject's body according to different embodiments of the present invention. [Modes for carrying out the invention]

[0040] (overview) In some thrombectomy techniques, a positive voltage is applied between a reference electrode and an active electrode that is in contact with, or at least adjacent to, the blood clot in the subject's body. This voltage causes the negatively charged blood clot to adhere to the positively charged active electrode. After the blood clot has adhered to the active electrode, the electrode is withdrawn from the body along with the blood clot.

[0041] A challenge in implementing these techniques is that the current generated from the applied voltage, and consequently the attractive force between the active electrode and the thrombus, can be distributed relatively non-uniformly over the length of the thrombus.

[0042] To address this challenge, embodiments of the present invention provide a device comprising an expandable multilayer electrode element. One layer of the electrode element functions as a reference electrode, while one or more other layers function as active electrodes. The electrode element is expanded to pass through and / or surround the thrombus along most or all of its length. A voltage is then applied between the active electrode and the reference electrode. As the electrodes extend along most or all of the length of the thrombus, the resulting current is distributed relatively evenly across the length of the thrombus.

[0043] In some embodiments, the expandable electrode element comprises a multilayer strip. For example, the expandable electrode element may comprise three layers: an active electrode layer, a reference electrode layer, and an intermediate insulating layer between the active electrode layer and the reference electrode layer. Alternatively, the expandable electrode element may comprise five layers, including two active electrode layers and two insulating layers.

[0044] Optionally, additional features of the multilayer strip can facilitate greater current flow between the active electrode layer and the reference electrode layer. Such features may include gaps in the insulating layer and / or reduced width.

[0045] In other embodiments, the expandable electrode element comprises a reference electrode core, an electrical insulating layer wound around the core, and an active electrode layer wound around the electrical insulating layer. The gap in the electrical insulating layer can facilitate the flow of current between the active electrode layer and the reference electrode core.

[0046] In some embodiments, the device comprises one or more electrode elements configured to extend to define one or more loops capable of capturing thrombi. The distal ends of the loops may be coupled to longitudinal elements passing through a sheath, thereby facilitating control over the electrode elements and allowing them to function as additional electrode elements. Alternatively or additionally, distal electrode elements may be positioned at the distal ends of the loops.

[0047] In other embodiments, the electrode elements are extended to define other shapes, such as a sinusoidal curve or a helical shape.

[0048] (Device description) First, refer to Figure 1, which is a schematic diagram of an apparatus 20 for removing a blood clot from a subject's body according to several embodiments of the present invention.

[0049] The device 20 includes a sheath 22 configured for insertion into the body, typically via the femoral vein, jugular vein, carotid artery, or radial vein of the subject. Following insertion of the sheath 22, the sheath is navigated to a thrombus typically located inside the subject's blood vessels. For example, the thrombus may be located inside the subject's pulmonary artery, carotid artery, femoral artery, popliteal artery, tibial artery, or peroneal vein.

[0050] In some embodiments, the sheath 22 is radiopaque, and the sheath is navigated under fluoroscopy. Alternatively or additionally, the sheath can be navigated on a guidewire and / or through a delivery catheter.

[0051] Typically, the sheath contains a flexible polymer. In some embodiments, the length of the sheath is 30 to 150 cm.

[0052] The device 20 further includes one or more expandable multilayer electrode elements 24 configured to advance towards the thrombus while being compressed inside the sheath 22. For example, following the navigation of the sheath 22 towards the thrombus, the electrode elements 24 can advance through the sheath. Alternatively, the electrode elements can advance together with the sheath to the thrombus while folded within the sheath.

[0053] The electrode element 24 is further configured to expand distally into the sheath following its advance toward the thrombus. For example, the electrode element may comprise a shape-memory material (e.g., nitinol) configured to expand to define a predetermined shape when exiting the sheath. Alternatively or additionally, as further described below with reference to Figure 3, a pair of longitudinal elements coupled to the electrode element can be used to expand the electrode element. Typically, the electrode element is placed on the thrombus or moved to a position adjacent to the thrombus (optionally, so that the electrode element contacts the thrombus) prior to the expansion of the electrode element.

[0054] In some embodiments, the electrode element 24 is configured to expand to define one or more circular or elliptical loops 26. For example, when expanded, the electrode element 24 can define an outer loop 26o and an inner loop 26i lying on the same plane. Alternatively, the electrode element can define two loops lying on different planes, such as planes perpendicular to each other. Advantageously, the loops 26 can capture thrombi.

[0055] Typically, the maximum width w0 of the widest loop 26 is greater than 2 mm and / or less than 30 mm, for example, between 2 mm and 30 mm, e.g., 3 to 20 mm.

[0056] Typically, in embodiments where the device 20 includes multiple loops 26, the loops are joined to each other (e.g., via any suitable adhesive) at a proximal joint 32p (located inside the sheath 22 in Figure 1) and a distal joint 32d.

[0057] In some embodiments, each loop 26 includes a single electrode element (i.e., a single electrode element defines the loop). In other embodiments, at least one loop includes multiple electrode elements, such as a pair of electrode elements. For example, the outer loop 26o may comprise a first electrode element 24a and a second electrode element 24b that are coupled to each other at a proximal junction 32p and a distal junction 32d.

[0058] Typically, when the electrode element is extended, the distance from the proximal end of the electrode element to the distal end of the electrode element (e.g., the distance from the proximal junction 32p to the distal junction 32d) is at least 10 mm and / or less than 100 mm, such as 10 to 100 mm, e.g., 20 to 80 mm.

[0059] As further described below with reference to Figures 2A-F, each electrode element 24 includes one or more reference electrodes 34 and one or more active electrodes 36. The active electrodes 36 are configured to attract thrombi when a voltage is applied between the active electrodes 36 and the reference electrodes 34 by a power supply 38 following the expansion of the electrode element. (Typically, the voltage between the active electrodes and the reference electrodes is positive so that the positively charged active electrodes attract the negatively charged thrombi). Following the attachment of the thrombus to the active electrodes, the device 20, along with the thrombus, is removed from the body.

[0060] Typically, the power supply 38 is current-regulated to a typical 0.1 to 10 mA, for example, 1 to 5 mA. In other embodiments, the power supply is voltage-regulated to a typical 0.1 to 50 V, for example, 1 to 40 V. The applied voltage may be constant or pulsed. Typically, the voltage is applied over a duration of 1 second to 10 minutes, for example, 5 seconds to 5 minutes, or for example, 10 seconds to 2 minutes.

[0061] The device 20 further comprises one or more longitudinal elements configured to be coupled to the electrode element and pass through the sheath. Each of the longitudinal elements can facilitate control of the electrode element and / or facilitate aspiration of thrombi.

[0062] For example, the apparatus 20 may include a proximal coupling longitudinal element 30 (e.g., a flexible hollow tube, a flexible solid wire, or a flexible solid shaft) coupled to the proximal end of each electrode element (e.g., to the joint 32p). To advance the electrode element from the sheath, the sheath may be pulled out while applying a reaction force to the longitudinal element 30, or the longitudinal element 30 may be pushed in while applying a reaction force to the sheath. (In each of the above cases, the reaction force may simply be enough to inhibit movement or it may be enough to cause movement in the opposite direction).

[0063] Alternatively or additionally, as shown in Figure 3, the apparatus 20 may include distally coupled longitudinal elements 60 (e.g., flexible hollow tubes, flexible solid wires, or flexible solid shafts) coupled to the distal ends of each electrode element. The distally coupled longitudinal elements 60 can be used to advance the electrode elements from the sheath, as described above for the proximal coupled longitudinal elements 30.

[0064] (In the context of this application, including the claims, the “proximal end” of each electrode element is the proximal end of the electrode element when it is extended. Similarly, the “distal end” of each electrode element is the distal end of the electrode element when it is unfolded.)

[0065] Alternatively or additionally, the apparatus 20 may include a first longitudinal wire (or "lead") 28a distally connected (e.g., soldered) to a reference electrode 34, and a second longitudinal wire (or "lead") 28b distally connected (e.g., soldered) to an active electrode 36. The first wire 28a and the second wire 28b are configured to be connected to different terminals of a power supply 38, so that a voltage can be applied between the electrodes by the power supply applying a voltage between the first and second wires.

[0066] Alternatively, the device 20 may comprise a plurality of first wires 28a, each connected to a different subset of the reference electrode. (In such an embodiment, one subset of the reference electrode may be activated by the power supply without activating another subset of the reference electrode.) Alternatively or additionally, the device 20 may comprise a plurality of second wires 28b, each connected to a different subset of the active electrode. (In such an embodiment, one subset of the active electrode may be activated by the power supply without activating another subset of the active electrode.)

[0067] In embodiments where the proximal coupling longitudinal element 30 or the distal coupling longitudinal element 60 is hollow, the first wire 28a and / or the second wire 28b can pass through the proximal coupling or distal coupling longitudinal element. Alternatively, the first wire 28a and the second wire 28b can run parallel to other longitudinal elements.

[0068] In other embodiments, the proximal-coupled longitudinal element 30 and / or distal-coupled longitudinal element 60 are connected to a power supply 38, and a voltage is applied to the electrodes through one or both of these longitudinal elements. For example, the proximal-coupled longitudinal element may connect one set of electrodes (e.g., active electrodes) to one terminal of the power supply, and the distal-coupled longitudinal element may connect the other set of electrodes (e.g., reference electrodes) to the other terminal. Alternatively, either the proximal-coupled or distal-coupled longitudinal element may connect one set of electrodes to one terminal of the power supply, and a wire may connect the other set of electrodes to the other terminal.

[0069] Figure 1 shows a cross-section 40 passing through the electrode element 24. Cross-sections 40 according to various different embodiments are shown in Figures 2A to 2D, which will be referred to next.

[0070] In some embodiments, each electrode element includes a multilayer strip 42. The layers of the strip 42 can be bonded to each other using any suitable adhesive.

[0071] For example, the reference layer 44r of the strip may include a reference electrode 34, one or more active layers 44a of the strip may include an active electrode 36, and the strip 42 may further include one or more insulating layers 44i that electrically insulate the reference layer 44r from the active layer 44a. When a voltage is applied, a current 46 flows between the active layer and the reference layer.

[0072] Typically, the width ws of the strip 42 (as shown in Figure 2A) is between 0.1 mm and 2 mm, for example between 0.2 and 1 mm, but at least less than 0.1 mm and / or 2 mm.

[0073] Typically, the thickness of each layer of strip 42 is less than 0.2 mm, such as less than 0.1 mm. Alternatively or additionally, the total thickness t of strip 42 (shown in Figure 2A) can be less than 1 mm, such as less than 0.5 mm, regardless of the number of layers in the strip.

[0074] In Figure 2A, the active layer 44a consists of a single active layer, and the insulating layer 44i consists of a single insulating layer positioned between the reference layer and the active layer. (Thus, the strip 42 contains a total of three layers). In some embodiments, the active layer is oriented inward (i.e., toward the longitudinal axis of the device 20) to better capture thrombi inside the loop 26 (Figure 1).

[0075] In Figure 2B, the active layer 44a includes a first active layer 44a_1 and a second active layer 44a_2 located on the opposite side of the reference layer 44r. The insulating layer 44i includes a first insulating layer 44i_1 located between the first active layer 44a_1 and the reference layer 44r, and a second insulating layer 44i_2 located between the second active layer 44a_2 and the reference layer 44r (thus the strip 42 includes a total of 5 layers). An advantage of this embodiment is that the thrombus capture is improved because the current 46 is increased and the area of ​​the active electrode is increased.

[0076] In Figure 2C, each active layer is shaped to define one or more outer gaps 48o, and each insulating layer is shaped to define one or more inner gaps 48i that are at least partially aligned with the outer gaps 48o. An advantage of such an embodiment is that additional current 46 may flow through the gaps. (For the sake of illustration, this additional current is not shown for all gaps). Similar to the five-layer strip in Figure 2B, the three-layer strip in Figure 2A can be formed to define outer gaps 48o and inner gaps 48i.

[0077] It should be noted that each gap may have any suitable length. For example, a gap may extend along the entire length of the strip so that the gap divides the layer of the strip into multiple cut segments.

[0078] In some embodiments, to facilitate the flow of additional current, at least one insulating layer 44i is narrower (e.g., 5–30% narrower) than the reference layer 44r or the active layer 44a adjacent to the insulating layer. Both the 3-layer strip in Figure 2A and the 5-layer strip in Figure 2B can have this feature. This feature can be combined with the gap in Figure 2C.

[0079] For example, in Figure 2D, the insulating layer is narrower than the reference layer 44r. Optionally, the active layer may have the same width as the insulating layer, as shown in Figure 2D.

[0080] Alternatively, the insulating layer may be narrower than the active layer. Optionally, the reference layer may have the same width as the insulating layer.

[0081] Next, we refer to Figure 2E, a schematic diagram of an electrode element 24 including a multilayer strip 42 according to several embodiments of the present invention. In contrast to Figures 2A-D, which show cross-sections through the electrode element, Figure 2E shows the electrode element along its length.

[0082] In some embodiments, the strip 42 typically includes a substrate layer 50 containing a polymer such as polyimide. One or more electrode layers 52 are attached to the substrate layer 50, for example, via any suitable adhesive. Each electrode layer 52 includes its respective reference electrode 34 and its respective active electrode 36. For example, as shown in Figure 2E, the strip 42 may include a single electrode layer 52. Alternatively, the strip 42 may include two electrode layers 52, each attached to a different side of the substrate layer 50.

[0083] In such embodiments, each active electrode typically includes one or more of the materials specified above for the active layer 44a, with reference to Figures 2A-D. Similarly, each reference electrode typically includes one or more of the materials specified above for the reference layer 44r.

[0084] In some embodiments, the electrode layer 52 further comprises an electrical insulating element 54 positioned between the active electrode and the reference electrode. Typically, to facilitate the flow of current, the electrical insulating element 54 has a thickness of less than 0.05 mm, such as less than 0.01 mm. In other embodiments, an air gap separates the two electrodes from each other.

[0085] Typically, the reference electrode and the active electrode protrude from each other to increase the length of the interface between the electrodes and thus increase the amount of current 46. For example, as shown in Figure 2E, the electrodes may have rectangular wave edges that combine with each other. Alternatively, for example, the electrodes may have sinusoidal wave edges that combine with each other.

[0086] Next, we refer to Figure 2F, which is a schematic diagram of another cross-section 40 passing through an electrode element according to some embodiments of the present invention.

[0087] In some embodiments, each electrode element includes a solid or hollow core 56 containing a reference electrode 34. For example, the core 56 may comprise a conductive wire that functions as the reference electrode. Each electrode element further comprises an electrically insulating layer 58i wound around the core and an active electrode 36, with an active layer 58a wound around the electrically insulating layer 58i.

[0088] Typically, in such embodiments, the active layer 58a is shaped to define one or more outer gaps 48o, and the electrical insulating layer 58i is shaped to define one or more inner gaps 48i that are at least partially aligned with the outer gaps 48o. Thus, current can flow between the electrodes through the gaps.

[0089] For example, the active layer 58a may comprise a conductive perforated tube that functions as an active electrode 36, and the electrical insulating layer 58i may comprise another perforated tube having pores at least partially aligned with those of the active layer 58a. Alternatively, the active layer 58a may include a conductive coil that functions as an active electrode 36, and the electrical insulating layer 58i may include another coil whose windings are at least partially aligned with those of the active layer 58a. Alternatively, either layer may include a coil, and the other layer may include a perforated tube having pores that lie at least partially between the windings of the coil. As yet another option, the active layer 58a may comprise a series of cut conductive tube segments that function as an active electrode 36, and the electrical insulating layer 58i may comprise another series of cut tube segments at least partially aligned with those of the active layer 58a.

[0090] Next, we refer to Figure 3, a schematic diagram of the apparatus 20 according to several embodiments of the present invention. (For ease of illustration, the first wire 28a and the second wire 28b are omitted from Figure 3).

[0091] As described above with reference to Figure 1, in some embodiments, the apparatus 20 includes a distal coupling longitudinal element 60 coupled to the distal end of each electrode element (for example, to the distal junction 28d). In embodiments in which the proximal coupling longitudinal element 30 is hollow, the distal coupling longitudinal element 60 may pass through the proximal coupling longitudinal element 30.

[0092] The distal longitudinal element 60, together with the proximal longitudinal element 30, can be used to adjust the respective length and width of the loop 26. For example, a user holding the proximal ends of the distal longitudinal element 60 and the proximal longitudinal element 30 protruding from the proximal end of the sheath 22 can slide the two longitudinal elements relative to each other. For example, to lengthen and narrow the loop, the user may push the distal longitudinal element 60 while applying a reaction force to the proximal longitudinal element 30. Conversely, to shorten or widen the loop, the user may push the proximal longitudinal element 30 while applying a reaction force to the distal longitudinal element 60 (in each of the above cases, the reaction force may simply inhibit movement or be sufficient to cause movement in the opposite direction).

[0093] Alternatively or additionally, regardless of whether the device 20 includes the loop 26, the distally connected longitudinal element 60 can be used together with the proximally connected longitudinal element 30 to extend the electrode element. For example, the user may push the distally connected longitudinal element 60 while applying a reaction force to the proximally connected longitudinal element 30.

[0094] Alternatively or additionally, regardless of whether the device 20 includes a loop 26, a distal longitudinal element 60 can be used with the proximal longitudinal element 30 to twist the electrode element around the thrombus following the expansion of the electrode element (and typically prior to the application of voltage) to increase contact between the electrode element and the thrombus. In other words, while a reaction force is applied to the distal longitudinal element 60, the proximal longitudinal element 30 may be rotated about its longitudinal axis, or while a reaction force is applied to the proximal longitudinal element 30, the distal longitudinal element 60 may be rotated (in each of the above cases, the proximal longitudinal element 30 and the distal longitudinal element 60 are such that the proximal longitudinal element is rotated while the proximal longitudinal element 30 is rotated. (In each of the above cases, the reaction force may simply inhibit rotation or be sufficient to cause rotation in the opposite direction).

[0095] In some embodiments, the distally connected longitudinal element 60—particularly at least the distal portion 60d of the distally connected longitudinal element 60 positioned between the proximal and distal ends of the loop when the loop is expanded—includes a longitudinal element active electrode, a longitudinal element reference electrode positioned inside the longitudinal element active electrode, and an electrical insulating element positioned between the longitudinal element reference electrode and the longitudinal element active electrode. Thus, the distally connected longitudinal element 60 can apply an additional attractive force to the thrombus. Typically, in such embodiments, the distally connected longitudinal element 60 is shaped to define a gap between the longitudinal element active electrode and the electrical insulating element to facilitate the flow of current between the longitudinal element active electrode and the longitudinal element reference electrode.

[0096] Alternatively or in addition to the distal joint longitudinal element 60, the device 20 may include distal electrode elements 70 positioned at the distal ends of each loop. The distal electrode element 70 comprises a distal active electrode, a distal reference electrode positioned inside the distal active electrode, and a distal electrical insulating element positioned between the distal reference electrode and the distal active electrode. Thus, the distal electrode element can apply an additional suction force to the thrombus. Typically, in such embodiments, the distal electrode element is formed to define a gap between the distal active electrode and the electrical insulating element to facilitate the flow of current between the distal active electrode and the distal reference electrode.

[0097] Typically, the length of the distal electrode element is between 10 and 100 mm, for example, 20 to 80 mm, and at least less than 10 mm and / or 100 mm. Typically, the distal electrode element 70 is narrower than w0 (Figure 1) to facilitate the removal of thrombi from distally stenotic vessels (i.e., vessels with a diameter that decreases distally), such as the pulmonary artery. In some embodiments, the distal electrode element 70 is cylindrical and has an outer diameter that is typically between 0.5 mm and 4 mm, for example, between 1 mm and 3 mm.

[0098] In some embodiments, as shown in Figure 3, the distal electrode element is completely distal to the electrode element 24. In other embodiments, the distal electrode element is only partially distal to the electrode element 24. For example, the proximal end of the distal electrode element 70 can be positioned inside the loop 26.

[0099] In some embodiments, as shown in Figure 3, the cross-section 62 of the distal coupling longitudinal element 60 and / or the cross-section 72 of the distal electrode element 70 appears to be similar to the cross-section 40 shown in Figure 2F. For example, the distal coupling longitudinal element 60 and / or the distal electrode element may comprise (i) a conductive core wire 64 serving as a reference electrode, (ii) an electrically insulating perforated tube 66 covering the core wire 64, and (iii) a conductive perforated tube 68 covering the perforated tube 66 and having holes at least partially aligned with those of the perforated tube 66, and serving as a working electrode. Alternatively or additionally, the distal coupling longitudinal element 60 and / or the distal electrode element may comprise any other suitable pair of gapped layers on the core wire 64, where the gaps in each layer are at least partially aligned with the gaps in the other layers. The layers may comprise, for example, a pair of coils, a perforated tube and a coil, or two sets of cut tube segments, as described above with reference to Figure 2F.

[0100] In some embodiments, the distal coupling longitudinal element 60 (e.g., its core wire 64) and / or the distal electrode element 70 (e.g., its core wire 64) are hollow. In such embodiments, the guidewire can pass through the distal coupling longitudinal element 60 and / or the distal electrode element.

[0101] In some embodiments, the distal electrode element 70 is coupled to the distal end of the loop 26, for example, the distal junction 28d. Alternatively or additionally, the distal electrode element may be coupled to the distal coupling longitudinal element 60. For example, a single core wire 64 may extend through both the distal coupling longitudinal element 60 and the distal electrode element. Alternatively, the distally coupled longitudinal element 60 may pass through the distal electrode element. (From the above, it can be seen that the distal coupling longitudinal element 60 may be indirectly coupled to the electrode element 24 via the distal electrode element).

[0102] In some embodiments, the distal coupling longitudinal element 60 extends distally to the electrode element. In such embodiments, the distal extension of the distal coupling longitudinal element 60 may have the characteristics of the distal electrode element 70 described above, such that the device 20 does not necessarily need to include the distal electrode element 70.

[0103] In some embodiments, any reference electrode belonging to the distal coupling longitudinal element 60 and the distal electrode element 70 is connected to the same first wire 28a (Figure 1) as the reference electrode belonging to the electrode element 24. Similarly, any active electrode belonging to the distal coupling longitudinal element 60 and the distal electrode element 70 is connected to the same second wire 28b (Figure 1) as the active electrode belonging to the electrode element 24. In other embodiments, the active electrode and / or reference electrode belonging to the distal coupling longitudinal element 60 and / or the distal electrode element 70 are connected separately from the electrode belonging to the electrode element 24 and are therefore activated.

[0104] In an alternative embodiment, each loop includes one or more active electrodes, but does not necessarily include a reference electrode, and the distally connected longitudinal element 60 includes one or more reference electrodes, but does not necessarily include an active electrode. When a voltage is applied between the active electrode and the reference electrode, a current flows between the active electrode and the reference electrode, and thus the active electrode attracts the thrombus.

[0105] For example, each electrode element may include a wire that functions as an active electrode without any additional layers. Similarly, the distally coupled longitudinal element 60 may include a core wire 64 that functions as a reference electrode without any additional layers.

[0106] Next, we refer to Figure 4, a schematic diagram of the apparatus 20 according to several embodiments of the present invention. (The closely coupled longitudinal elements 30 are omitted from Figures 4-5 for ease of illustration.)

[0107] In some embodiments, the electrode element 24 defines a proximal set of one or more proximal loops 26p and a distal set of one or more distal loops 26d. For example, the proximal loops 26p may comprise an outer proximal loop 26p_o and an inner proximal loop 26p_i lying on the same plane, and the distal loops 26d may similarly comprise an outer distal loop 26d_o and an inner distal loop 26d_i lying on the same plane as the proximal loops. Alternatively, the loops may have any other suitable configuration, for example, the distal loops 26d may be located in a plane perpendicular to the plane on which the proximal loops 26p lie.

[0108] The distal loop 26d is connected to the distal ends of the proximal loops 26p. For example, the proximal ends of the distal loops can be connected to each other at the inter-loop junction 74 and then to the distal end of the proximal loop.

[0109] Typically, the distal set has a maximum width w2 that is smaller than the maximum width w1 of the proximal set. (The maximum width of each set is the maximum width of the widest loop within the set. Typically, w1 is greater than 2 mm and / or less than 30 mm, between 2 mm and 30 mm, e.g., 3-20 mm). Advantageously, this feature facilitates the removal of thrombi from distal stenotic vessels.

[0110] The device 20 may be equipped with any number of additional sets of loops (typically having progressively smaller maximum widths) distal to the distal loop 26d.

[0111] In some embodiments, the apparatus 20 further comprises a distal coupling longitudinal element 60 coupled to the distal end of the most distal loop, and / or a distal electrode element 70 located at the distal end of the most distal loop.

[0112] The electrode element 24 may have any suitable multilayer configuration, such as any of the configurations described above with reference to Figures 2A to F. Alternatively, as described above with reference to Figure 3, each electrode element may constitute an active electrode without any additional layers, and current can flow between the electrode element and the distally coupled longitudinal element 60.

[0113] Next, we will refer to Figure 5, which is a schematic diagram of the apparatus 20 according to several embodiments of the present invention.

[0114] In some embodiments, as shown in Figure 5, at least one electrode element 24 has a sinusoidal shape when extended. Alternatively or additionally, at least one electrode element may have a helical shape when extended. Such electrode elements may have any suitable multilayer configuration, such as any of the configurations described above with reference to Figures 2A-F. Furthermore, such electrode elements can be combined with any of the features described above with reference to the earlier figures, such as the distally coupled longitudinal element 60 (Figure 3).

[0115] Generally, to facilitate the removal of thrombi from distally stenotic vessels, electrode elements can be configured to expand to define any shape having a width that decreases as it moves distally along the distal portion of the shape, for example, approximately 50%, 30%, or 10% of the shape. Examples of such shapes include loops (as shown in Figures 1, 3, and 4) and the sinusoidal shape in Figure 5, where the "width" of the latter shape is the width of the sinusoidal envelope.

[0116] Typically, each of the active electrodes described herein comprises gold, platinum, and / or an alloy of platinum and iridium. Typically, each of the reference electrodes described herein comprises stainless steel, nitinol, and / or titanium. (As described above with reference to Figure 1, shape memory materials such as nitinol may facilitate the expansion of electrode elements.) Typically, each of the insulating elements described herein comprises one or more biocompatible polymers such as polyether block amide, polyimide, or polyurethane.

[0117] Those skilled in the art will understand that the present invention is not limited to what is specifically shown and described herein. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described herein, as well as variations and modifications therein that are not in the prior art and that will come to mind for those skilled in the art from reading the foregoing description. [Explanation of symbols]

[0118] 20 equipment 22 Sheath 24 Multilayer electrode element 26 loops 32p Proximal junction 32d Distal junction

Claims

1. 1. An apparatus comprising: one or more longitudinal elements configured to pass through a sheath within a subject's body; one or more expandable multi-layer electrode elements coupled to the longitudinal element, the one or more expandable multi-layer electrode elements configured to be collapsed within the sheath while being advanced to a thrombus within the body and to expand distally into the sheath following advancement to the thrombus; Equipped with Each of the electrode elements comprises: one or more reference electrodes; one or more active electrodes configured to attract the thrombus upon application of a voltage between the active electrode and the reference electrode following expansion of the electrode element; Including, one or more active layers comprising said active electrode; the device includes one or more insulating layers that electrically insulate the reference electrode from the active electrode; each of the active layers is shaped to define one or more outer gaps, and each of the insulating layers is shaped to define one or more inner gaps at least partially aligned with the outer gaps.

2. The device of claim 1 , wherein the longitudinal elements include proximal coupling longitudinal elements coupled to the proximal ends of each of the electrode elements.

3. The device of claim 1 , wherein the longitudinal elements include distally coupled longitudinal elements coupled to the distal ends of each of the electrode elements.

4. The distal coupling longitudinal element comprises: a longitudinal element active electrode; a longitudinal element reference electrode disposed inwardly of the longitudinal element active electrode; an electrically insulating element disposed between the longitudinal element reference electrode and the longitudinal element active electrode; The apparatus of claim 3 , comprising:

5. The device of claim 4 , wherein the distal coupling longitudinal element extends distally relative to the electrode element.

6. The device of claim 1 further comprising the sheath.

7. The device of any one of claims 1 to 6, wherein each of the electrode elements comprises a multi-layer strip.

8. a reference layer of the strip comprising a reference electrode; one or more active layers of the strip include an active electrode; 8. The device of claim 7, wherein the strip further comprises the one or more insulating layers, the one or more insulating layers electrically insulating the reference layer from the one or more active layers.

9. 9. The device of claim 8, wherein the one or more active layers comprise a single active layer, and the one or more insulating layers comprise a single insulating layer disposed between the reference layer and the active layer.

10. the one or more active layers include a first active layer and a second active layer disposed on either side of the reference layer, and the one or more insulating layers are a first insulating layer disposed between the first active layer and the reference layer; a second insulating layer disposed between the second active layer and the reference layer; The apparatus of claim 8 , comprising:

11. 9. The device of claim 8, wherein at least one of the one or more insulating layers is narrower than an adjacent one of (i) the reference layer, or (ii) the one or more active layers.

12. The strip a substrate layer; one or more electrode layers attached to the substrate layer; Including, 8. The device of claim 7, wherein each of the one or more electrode layers includes a respective one of the one or more reference electrodes and a respective one of the one or more active electrodes.

13. Each of the electrode elements comprises: a core including the one or more reference electrodes; an electrical insulating layer wrapped around the core; an active layer including the active electrode and wound around the electrically insulating layer; 7. The apparatus of claim 1, comprising:

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