Thrombus extraction device

Abstract

Disclosed is a thrombus extraction device (1) comprising: a rotating body (2) formed by a plurality of first longitudinal struts (20), wherein the first longitudinal struts (20) are fixed only at a proximal end (21) and a distal end (22), and the rotating body (2) is in an expanded configuration when the rotating body is in a free state, and is in a contracted configuration when the rotating body is inserted into a catheter; a distal body (3) connected to the distal end (22) of the rotating body (2), the distal body is in an expanded configuration when the distal body is in a free state, and is in a contracted configuration when the distal body is inserted into a catheter; wherein at least a portion of each first longitudinal strut (20) is radially expanded and circumferentially rotated during the unfolding stage of the rotating body (2) from the contracted configuration to the expanded configuration.

Description

Technical Field

[0001] This invention relates to a thrombus removal technique, and more particularly to a thrombus removal device for capturing and removing obstructions such as thrombi or other substances that have formed or remain in a patient's cranial arteries. Background Technology

[0002] Thrombi that form or remain in a patient's cranial artery can cause acute ischemic stroke. These thrombi block blood flow in the affected artery and cause irreparable damage to brain tissue, leading to a high incidence of illness and even death. Current devices designed to remove such thrombi and restore blood flow have achieved varying degrees of success. It is well known that thrombus material can vary in texture, which can be challenging for some devices. Often, the removal device cannot remove the entire thrombus in a single attempt, meaning that blood perfusion to the affected artery is not restored. Furthermore, to remove a sufficient amount of thrombus and restore blood flow, the removal process may require multiple attempts, meaning the device must advance through the thrombus again, unfold again, and retract before being retracted proximally to the aspiration catheter opening and reinserted into the microcatheter. All of this requires time and effort from clinicians and prolongs the period when parts of the patient's brain are hypoxic.

[0003] All mechanical thrombectomy devices must advance through the thrombus via a microcatheter in a coiled-contract configuration. They then exit the microcatheter, radially expand to an unfolded state, and engage with the thrombus. The thrombus permeates the struts of the thrombectomy device, allowing the device to "grab" the thrombus, ensuring it is sufficiently gripped for removal when the clinician pulls on the device. Most thrombectomy devices engage with the thrombus via radial expansion upon withdrawal from the microcatheter. Their effectiveness in permeating and grasping the thrombus depends primarily on the unit area size of the resulting stent structure (i.e., the size of the open space between adjacent struts) and the radially outward force generated by that structure. If the force exerted on the thrombus by the thrombectomy device is greater than the force acting on the thrombus within the blood vessel, the thrombus will be removed. See [link to relevant documentation]. Figure 1 :

[0004] F retrieval >F resistant

[0005] As shown in the diagram below, the force acting on a thrombus within a blood vessel has two components:

[0006] F retrieval =F friction +F impaction

[0007] in:

[0008] F friction It is the force generated by the "adhesion" of the thrombus on the blood vessel wall.

[0009] F impaction It is the force generated by the blood pressure difference (proximal to distal) on the thrombus.

[0010] For current devices, there are two different methods for thrombus binding and removal. Second-generation devices, now considered "primitive" (e.g., Medtronic Solitaire, Stryker Trevo), generate radial forces to fully penetrate the thrombus and achieve a sufficiently strong grip to hold it when removed by rolling or dragging. This effectively traps the thrombus between the vessel wall and the stent, effectively "rolling" it proximally during stent retraction. The greater the radial force, the greater the gripping force on the thrombus, but the greater the friction between the thrombus and the vessel wall, as the thrombus is pushed against the vessel wall with greater force. If the radial force of the structure is already too high, this thrombus removal mechanism can have some of the opposite effect. Third-generation devices (e.g., Cerenovous Embotrap II, MicroVention ERIC) remove thrombi through more pushing motion. They are designed with larger spaces between the stent modules into which the thrombus will seep, so the force applied to the thrombus is primarily tangential to the vessel wall along the proximal axial direction, without the same radial outward component acting on the thrombus. This is used to limit the wall friction forces experienced by the thrombus due to stent deployment and is designed to provide easier thrombus removal.

[0011] Regardless of the thrombus removal mechanism, such as Figure 2 As shown, most devices move from their coiled, contracted state (i.e., within the microcatheter) to their expanded, expanded state through a purely radial expansion motion. This means that the structural struts penetrate the thrombus material purely through radially outward movement. Nothing is likely to act on the thrombus, except:

[0012] • During the unfolding of the structure, in the radially outward direction

[0013] • During the removal of the structure in the axial direction.

[0014] In this regard, there is a desire for an improved device to overcome some of the shortcomings of existing devices and to achieve more effective thrombus removal. Summary of the Invention

[0015] This invention provides a thrombus removal device. The device provides engagement with the thrombus through a combination of radial and circumferential movements during the deployment phase and an axial movement during the removal phase. The combined radial and circumferential movements are achieved purely by the geometry of the struts and how they return to their near-expanded state when pushed out from the microcatheter outlet.

[0016] In one embodiment of the present invention, a thrombus removal device is provided, comprising: a rotating body formed of a plurality of first longitudinal struts, wherein the first longitudinal struts are fixed only at their proximal and distal ends, the rotating body having an expanded configuration when in a free state and a contracted configuration when the rotating body is inserted into a catheter; and a distal body connected to the distal end of the rotating body, the distal body having an expanded configuration when in a free state and a contracted configuration when the distal body is inserted into a catheter; wherein, during the unfolding phase of the rotating body from the contracted configuration to the expanded configuration, at least a portion of each first longitudinal strut undergoes radial expansion and circumferential rotation.

[0017] Preferably, the plurality of first longitudinal struts have substantially the same geometry as each other.

[0018] Preferably, each of the plurality of first longitudinal struts is elongated and has a bend along the longitudinal direction of the rotating body and a bend around the circumference of the rotating body.

[0019] Preferably, each of the plurality of first longitudinal struts can be formed by the following steps: providing a substantially straight strut; bending the strut into a flat geometry, i.e., substantially in a plane and having a bending shape including at least one peak along the longitudinal direction of the flat geometry; and encircling the flat geometry in an arc shape on a forming mandrel, the longitudinal direction of the flat geometry being substantially parallel to the longitudinal direction of the mandrel.

[0020] Preferably, the flat geometry includes 2, 3, or 4 repeating peaks.

[0021] Preferably, the flat shape is substantially a sine wave shape or a triangular wave shape.

[0022] Preferably, the forming mandrel has a circular, elliptical, or polygonal cross-section.

[0023] Preferably, the forming mandrel has a uniform cross-section.

[0024] Preferably, the forming mandrel is tapered, with a larger diameter at the proximal end and / or the distal end.

[0025] Preferably, the rotating body is formed by three first longitudinal struts, wherein a plurality of the first longitudinal struts are fixed together at the proximal and distal ends.

[0026] Preferably, the distal body is formed by a plurality of second longitudinal struts, wherein the second longitudinal struts are fixed only at the first end and the second end.

[0027] Preferably, the plurality of second longitudinal struts have substantially the same geometry and are arranged in a substantially rotationally symmetrical manner.

[0028] Preferably, each of the plurality of second longitudinal struts is elongated and has a bend along the longitudinal direction of the distal body and a bend around the circumference of the distal body.

[0029] Preferably, each of the plurality of second longitudinal struts is formed by the following steps: providing a substantially straight strut; bending the strut into a flat geometry, the flat geometry being in a plane and having a bending shape including at least one peak along the longitudinal direction of the flat geometry; and enclosing the flat geometry in an arcuate manner over a forming profile, the longitudinal direction of the flat geometry being substantially in the same plane as the longitudinal direction of the forming profile.

[0030] Preferably, the flat geometry of the second longitudinal strut includes a peak.

[0031] Preferably, the flat geometry of the second longitudinal support is substantially sinusoidal.

[0032] Preferably, the forming profile is an ellipsoidal forming profile.

[0033] Preferably, the number of second longitudinal supports is greater than the number of first longitudinal supports.

[0034] Preferably, the distal body is formed by six second longitudinal struts, and the six second longitudinal struts form a spherical space between them during expansion construction.

[0035] Preferably, a plurality of second longitudinal supports are fixed together at the first end and the second end.

[0036] Preferably, the number of first longitudinal support rods and second longitudinal support rods is the same, and each of the plurality of first longitudinal support rods is integrally formed with a corresponding one of the plurality of second longitudinal support rods.

[0037] Preferably, the plurality of second longitudinal struts are formed of shape memory material.

[0038] Preferably, the plurality of first longitudinal struts are formed of shape memory material.

[0039] Preferably, the shape memory material is a nickel-titanium alloy.

[0040] Preferably, each of the plurality of first longitudinal struts and the plurality of second longitudinal struts is a metal wire with a diameter of 80 micrometers.

[0041] Preferably, it further includes: a push guidewire connected to the proximal end of the rotating body; and a microcatheter having a channel for receiving the distal body, the rotating body, and the push guidewire.

[0042] Unlike other existing mechanical thrombectomy devices, according to the present invention, the strut in the rotating body engages with the thrombus in the blood vessel through a combination of radial expansion and circumferential rotation. This structure has a significantly stronger ability to penetrate the thrombus than existing mechanical thrombectomy devices. Existing devices simply expand radially into the thrombus, and to some extent, this leads to compression of the blood vessel wall by the thrombus. Due to the geometry of such devices and the radial force they generate, the ability of the thrombus to penetrate these thrombectomy devices is reduced. Excessive radial force can cause problems during device removal. However, through radial expansion and rotation, the structure proposed in this invention will penetrate the thrombus using two different deformation modes, which will result in a more effective engagement with the thrombus. Furthermore, the proposed structure is much more likely to detach the thrombus from the blood vessel wall compared to conventional mechanical thrombectomy devices. Loose thrombi are easier to remove from the blood vessel because the initial adhesion to the blood vessel wall is broken. Once the thrombus has detached from the blood vessel wall, it will be intercepted by the strut of the rotating body, or it will be intercepted by the much denser distal body. Attached Figure Description

[0043] Figure 1 The force acting on an arterial thrombus is shown.

[0044] Figure 2 The pure radial expansion of a standard support structure is shown.

[0045] Figure 3 A plan view of a thrombus removal device according to an embodiment of the present invention is shown.

[0046] Figure 4 An axonometric view of a thrombus removal device according to an embodiment of the present invention is shown.

[0047] Figure 5 An axial view of a thrombus removal device according to an embodiment of the present invention is shown.

[0048] Figure 6 A flat (planar) geometry for forming a support rod of a rotating body according to an embodiment of the present invention is shown.

[0049] Figure 7 The transformation of a planar body to a cylindrical geometry according to an embodiment of the present invention is illustrated.

[0050] Figure 8 A cross-sectional view of the rotating body according to an embodiment of the present invention illustrates the rotational motion during deployment.

[0051] Figure 9 The location of the tracking point on the rotating body is shown.

[0052] Figure 10 The quantification of rotational twist as a result of radial unfolding is shown.

[0053] Figure 11 It is an axonometric view of the independent distal main body geometry.

[0054] Figure 12 It is an axial view of the independent distal main body geometry.

[0055] Figure 13 The transformation of the planar geometry of the distal body is shown.

[0056] Figure 14 The distal body is shown fully formed on a forming tool.

[0057] Figure 15 Some examples of the shape of the first longitudinal support according to the invention are shown.

[0058] Figure 16 Some examples of cross-sections of the molded mandrel according to the present invention are shown.

[0059] Figure 17 Some examples of the longitudinal profile of the molded mandrel according to the present invention are shown. Detailed Implementation

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While any methods and materials similar to or equivalent to those described herein may be used in the practice or testing of the embodiments described herein, preferred methods, apparatus, and materials are described herein.

[0061] Specific embodiments of the invention will now be described in detail with reference to the accompanying drawings, wherein like reference numerals denote like or functionally similar elements. The terms “distal” or “proximal” are used in the following description of position or orientation relative to the clinician. “Distal” or “distally” means a position away from or in a direction away from the clinician. “Proximal” or “proximally” or “proximate” means a position close to or towards the clinician.

[0062] See Figure 3-5This disclosure provides a thrombus removal device (or mechanical thrombectomy device) 1, which includes a rotating body 2. When the rotating body 2 is inserted into a catheter or microcatheter, it can be in a contracted configuration for easy delivery; when the rotating body 2 is in a free state or when it is removed from the catheter to remove the thrombus, it is in an expanded configuration. The rotating body 2 is formed by a plurality of first longitudinal struts 20, which are fixed only at their proximal ends 21 and distal ends 22. At least a portion of each first longitudinal strut 20 simultaneously expands radially and rotates circumferentially during the unfolding phase of the rotating body 2 from the contracted configuration to the expanded configuration. The thrombus removal device 1 also includes a distal body 3, which is in an expanded configuration when in a free state and can be in a contracted configuration when the distal body 3 is inserted into a catheter. The distal body 3 is the distalmost part of the entire structure and is the first part to unfold in the device 1, unfolding before the rotating body 2. The rotating body 2 is the connection between the guidewire pusher and the distal body 3.

[0063] When rotation and / or angular variation are discussed in the context of this invention, it primarily refers to rotation when the strut is rotated about the longitudinal axis of the thrombus removal device. The purpose of rotation is to dislodge the thrombus from the vessel wall before it is dragged to the "football" feature. It achieves the essential loosening effect on the thrombus that the inventors of this invention sought to implement, making it easier to remove. No other concept or thrombus recovery device on the market is found designed to achieve such an action during the removal process.

[0064] In one embodiment, see Figure 3-5 The rotating body 2 is formed by three first longitudinal support rods 20, which are connected to each other at the proximal end 21 and the distal end 22. The proximal end 21 and the distal end 22 are the only two points where the three first longitudinal support rods 20 are connected to each other. Preferably, the three first longitudinal support rods 20 are welded together at the proximal end 21 and the distal end 22 to maintain the integrity of the structure.

[0065] In other embodiments, more than three first longitudinal struts 20 may be provided. The first longitudinal struts 20 may be fixed at the proximal end 21 and the distal end 22 in other ways, for example, fixed at the proximal end 21 to the push guide wire and / or fixed at the proximal end of the distal body 3.

[0066] The three first longitudinal struts 20 have substantially the same geometry as each other. Each of the plurality of first longitudinal struts 20 is elongated and has a bend along the longitudinal direction of the rotating body 2 and a bend around the circumference of the rotating body 2.

[0067] See Figure 6-7 Each of the plurality of first longitudinal struts 20 can be formed by the following steps: providing a substantially straight strut; bending the strut into a flat geometry, such as... Figure 7 As shown, it has a roughly sinusoidal shape in a plane and along the longitudinal direction of the flat geometry; the flat geometry is wrapped in an arc around the cylindrical forming mandrel, and the longitudinal direction of the flat geometry is parallel to the longitudinal direction of the mandrel.

[0068] Specifically, flat geometry is a two-dimensional geometry, and it typically has a shape similar to a sine curve. Essentially a straight support is bent into a sine-like shape and lies essentially within a plane. Optional, such as Figure 6 As shown, the two ends of the support rod remain straight, while the middle section is bent into a shape resembling a sine curve. Two shape cycles are obtained in the support rod through the bending process. Other numbers of shape cycles can be provided in the flat geometry of the support rod. Preferably, the flat geometry has a longitudinal direction substantially the same as the longitudinal direction of the straight support rod. This sine-like shape can be referred to as a curve along the longitudinal direction.

[0069] According to other embodiments, the flat geometry of the support rod can be other shapes, such as... Figure 15 As shown. The basic function of the rotating body can be achieved through a shape composed of peaks "macroscopically," with the peaks remaining fixed only at the endpoints of the macroscopic shape. There can be a single basic peak structure or multiple repetitions of this peak structure. This macroscopic shape is then "wrapped" in an arc around a cylindrical mandrel to form the overall structure of the thrombus removal device. The entire peak structure does not necessarily have to be a perfect sine curve. Any structure with a basic peak structure can produce the same effect. The shape of the wires between the peaks can be characterized by very simple straight-line connections (such as...). Figure 15 The top shape (as in the top section), the connection formed by curves (such as the second shape from top to bottom), the circular shape (or parabolic shape, such as the third and fourth rows above), or the partial sine curve shape (such as the bottom two rows). According to a preferred embodiment, the flat geometry of the first longitudinal strut can be substantially sinusoidal or triangular, including one, two, three, four, or more repeating peaks.

[0070] Figure 16 Examples of cross-sections of the molded mandrel according to the invention are shown. The cross-section of the molded mandrel can be circular, elliptical, or polygonal. From a practical point of view, considering its unfolding into a cylindrical artery within the body, the profile of the molded cross-section needs to be substantially cylindrical (or at least elliptical). From a technical point of view, the profile of the molded cross-section can be essentially polygonal and still produce a rotational motion during unfolding.

[0071] Figure 17Some examples of longitudinal sections of the molded mandrel according to the invention are shown. For the longitudinal section, again from a practical point of view, considering the nature of the vessels it unfolds into, it should be substantially cylindrical. However, it can also be tapered, with advantages in either direction:

[0072] a) It can be tapered, with a larger diameter at the proximal end of the structure, thus tapering gradually to match the natural taper of the blood vessel (i.e., because the diameter of the blood vessel decreases as it transitions distally).

[0073] b) It can be conical, with a larger diameter at the distal end of the structure to ensure that thrombus material is pushed forward at that distal end during thrombus removal.

[0074] The final configuration of the rotating body is, to some extent, a "dogbone" shape.

[0075] When drawn into the delivery conduit, these peaks naturally straighten due to the conduit's constraint on the structure. However, the unfolding action (i.e., pushing the structure out of the delivery conduit) removes this constraint, allowing the macrostructure to return to its post-formed shape. It is this return to its post-formed shape that generates the rotational motion.

[0076] Next, the flat geometric shape is wrapped around the cylindrical forming mandrel in an arc shape, with the longitudinal direction of the flat geometric shape parallel to the longitudinal direction of the mandrel, resulting in the following: Figure 7 The shape of the first longitudinal strut 20 is shown. Although the flat geometry is shown as having a pattern similar to a sine curve, in some embodiments, the flat geometry can have any other suitable bending configuration. This bending, obtained by wrapping a cylindrical mandrel in an arc shape, can be referred to as bending in the circumferential direction.

[0077] The method used to obtain the first longitudinal support 20 is merely an example. It can also be made in other ways, such as 3D printing.

[0078] In one embodiment of the invention, three first longitudinal struts are formed through the steps described above, and then fixed or welded together at the proximal end 21 and the distal end 22, respectively. Preferably, the three first longitudinal struts are fixed together in a substantially rotationally symmetrical manner. The proximal end 21 of the rotating body 2 may be connected to a push guide wire (not shown).

[0079] Due to the geometry and connection pattern of the first longitudinal support 20, the rotating body 2 can have radial expansion and circumferential rotation during its unfolding phase from a contraction structure to an expansion structure.

[0080] In one embodiment, the rotating body 2 is made of a shape memory material, preferably a nickel-titanium alloy, and is self-expanding from a contracted configuration to an expanded configuration. Any other biocompatible, hyperelastic metallic material is also acceptable. The rotating body 2 automatically recovers its shape once released from the contracted, tightening delivery configuration. The material can be in various forms, such as wire or tubing. The diameter of the wire or the outer diameter of the tubing is typically between 50 micrometers and 250 micrometers. In one embodiment, the rotating body 2 is made of a circular nickel-titanium alloy wire with a diameter of approximately 80 micrometers. Any process suitable for forming shape memory materials can be used accordingly when fabricating the first longitudinal support 20.

[0081] The rotating body 2 can have various lengths and diameters. In one embodiment, the flat geometry of the rotating body 2 can have, for example, the following: Figure 6 The length shown is 47.4 mm measured from proximal to distal along the longitudinal axis; other ranges and dimensions are also possible. The overall diameter of the formed structure will be comparable to market-leading devices, i.e., dimensions are appropriately determined to cover artery diameters ranging from 2.0 mm to 6.0 mm, with working lengths ranging from 20 mm to 40 mm.

[0082] Typically, the structure of the rotating body 2 after molding is "oversized" relative to the blood vessel to be deployed therein to ensure positive pressure engagement with the blood vessel. A typical oversize can be between 10% and 33%. Therefore, in some embodiments, if the diameter of the artery to be covered ranges from 2.0 mm to 6.0 mm, the diameter of the cylindrical mandrel can range from 2.2 mm to 8 mm.

[0083] The rotating body 2 can be delivered via a microcatheter (not shown) to the desired location to remove thrombi from cranial arteries. When in a constricted configuration, the rotating body 2 is coiled or inserted into the microcatheter for delivery. At the desired location in the cranial artery, the rotating body 2 is extended from the microcatheter, attempting to recover from the deformation experienced during coiling due to the hyperelastic properties of the nickel-titanium alloy. In other words, it attempts to return to its expanded shape or configuration. As the rotating body 2 automatically recovers its expanded shape from the constricted configuration, it penetrates the thrombus, engages with it, and traps it during removal. Due to the sinusoidal geometry of the struts 20 and their connection pattern, the rotating body 2 undergoes a significant degree of rotational motion during its radial expansion and recovery. Therefore, unlike other thrombectomy devices, the rotating body 2 exhibits both radial and circumferential deformation components during its unfolding phase. This can be well illustrated using a finite element model simulated by a computer. Therefore, the rotating body 2 can also dislodge thrombi from the vessel wall through its rotational action during unfolding.

[0084] In the finite element model, the sectional view shows the undeformed expanded state and the deformed contracted state, allowing for the assessment and understanding of the level of rotational motion in the structure due to unfolding. (Refer to...) Figure 8 The first geometry 23 represents the deformable structure, while the second geometry 24 is the unfolded / expanded geometry. The radial unfolding of the device alone will cause a rotation of Δθ within the structure.

[0085] If certain positions within the rotating body 2 are marked and tracked during this unfolding process, the magnitude of this rotation can be accurately quantified. (Refer to...) Figure 9-10 Three such positions were identified at different locations on the main body, and the rotation was plotted as a function of radial variation. It can be seen that, depending on the position along the rotating main body 2, certain parts of the structure rotate up to 65 degrees. Again, this rotation is fundamentally due to the geometry of the device. No active load is applied to the structure except when it is pushed out of the microcatheter and returns to its unfolded / expanded geometry.

[0086] The amount of rotation is related to the degree to which the strut is forced to "wrap" around the circumference during the forming process. In the geometry formed according to some embodiments, each sinusoidal flat strut wraps around half the circumference of the forming mandrel in an arc. So the flat strut is wrapped around the cylinder by 180 degrees. When rolled up, it straightens to enter the guide tube, and in doing so, it rotates by a certain angle. As the rotating body is pushed out of the guide tube and expands, it rotates circumferentially. Depending on the position on the rotating body, different parts can rotate at different angles. The area or part experiencing the maximum rotation is likely to be the area or part farthest from the fixed end point, and in the current configuration, the maximum rotation angle can be approximately 65 degrees.

[0087] However, the rotation angle can be larger or smaller if the flat geometry can wrap around the mandrel at more or less angle, or if the rotating body can be fitted into smaller or larger catheters. In summary, the rotating body according to the invention can achieve a suitable rotation angle by appropriately setting the wrap angle on the mandrel and / or the size of the catheter. The wrap angle is preferably 180 degrees, but in some embodiments it can be other degrees, such as 30 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees, or greater than 180 degrees.

[0088] In this embodiment, the rotating body 2 engages with the thrombus through a combination of radial and circumferential movements during the unfolding phase and an axial movement during the removal phase. The combination of radial and circumferential movements is entirely due to the geometry of the first longitudinal struts 20 and how they return to their near-expanded state when pushed out from the microcatheter outlet.

[0089] The significance of this deformation lies in the fact that, unlike other mechanical thrombectomy devices, the first longitudinal strut 20 engages with the thrombus in the blood vessel through a combination of radial expansion and circumferential rotation. Therefore, this structure has a significantly greater ability to penetrate the thrombus than existing mechanical thrombectomy devices. Existing devices simply expand radially into the thrombus, and to some extent, this leads to compression of the vessel wall by the thrombus. The ability of the thrombus to penetrate these thrombectomy devices depends on the geometry of the device and the radial force it generates. Too much radial force can cause problems during device removal. However, through radial expansion and rotation, the proposed structure will penetrate the thrombus using two different deformation modes, resulting in a more effective engagement with the thrombus. Furthermore, due to this structure of the rotating body 2, the proposed structure is much more likely to detach the thrombus from the vessel wall compared to conventional mechanical thrombectomy devices. The advantage of this is that loosened thrombi are more easily removed from the blood vessel because the original adhesion to the vessel wall is broken. Once the thrombus has detached from the vessel wall, it will be intercepted by the strut of the rotating body 2 or the distal body 3.

[0090] In a preferred embodiment, the distal body 3 is formed by a plurality of second longitudinal struts 30, wherein the second longitudinal struts 30 are fixed only at the first end 31 and the second end 32, and the first end 31 of the distal body 3 is connected to the distal end 22 of the rotating body 2. Preferably, the number of second longitudinal struts of the distal body is greater than the number of first longitudinal struts of the rotating body. In one embodiment, the distal body 3 is formed by six second longitudinal struts 30. Therefore, when viewed axially, the distal body 3 has a denser network structure than the rotating body 2. Once a thrombus detaches from the vessel wall, it is either trapped by the struts of the rotating body 2 or by the much denser network structure of the distal body 3.

[0091] In one embodiment, the distal body 3 and the rotating body 2 are constructed independently as two separate objects and connected by welding, adhesive, brazing, or other robust methods. In another embodiment, the struts used to form the rotating body 2 can also continue to form the structure of the distal body 3. The distal body 3 may have a matching number of struts as the rotating body 2. Such a construction would be more robust than any other connection configuration, but more complex to manufacture.

[0092] The first end 31 and the second end 32 are the only two points where the six second longitudinal struts 30 are fixed or connected to each other. In one embodiment, the six second longitudinal struts 30 are welded together at the first end 31 and the second end 32 to maintain the overall structure.

[0093] The six longitudinal struts 30 have substantially the same geometry as each other. Each second longitudinal strut 30 is elongated and has a bend along the longitudinal direction of the distal body 3 and a bend around the circumference of the distal body 3.

[0094] Reference Figure 13-14 Each second longitudinal strut 30 in the distal body 3 can be formed by the following steps: providing a substantially straight strut; bending the strut into a flat geometry, such as... Figure 13 As shown, it has a shape that is basically sinusoidal in a plane and along the longitudinal direction of the flat geometry; the flat geometry is wrapped around the ellipsoidal forming profile, and the longitudinal direction of the flat geometry and the longitudinal direction of the ellipsoidal forming profile are basically in the same plane.

[0095] Specifically, flat geometry is a two-dimensional geometry. A basically straight support is bent into a shape that is essentially a sine curve within a plane. This sine-like shape can be described as a curve along the longitudinal direction.

[0096] Next, the flat geometric shape is wrapped around the ellipsoidal forming profile in an arc, so that the longitudinal direction of the flat geometric shape and the longitudinal direction of the ellipsoidal forming profile are basically in the same plane, thus obtaining the shape of the second longitudinal support 30. This bending obtained by wrapping the ellipsoidal forming profile in an arc can be called bending in the circumferential direction.

[0097] The method for obtaining the second longitudinal support rod 30 is merely an example. It can also be made in other ways, such as 3D printing.

[0098] exist Figure 14 In this configuration, each of the six second longitudinal struts 30 is radially equidistant around the longitudinal direction, or the six second longitudinal struts are fixed together in a substantially rotationally symmetrical manner. A spherical space is formed between the six second longitudinal struts. Although the flat geometry is shown as having a sinusoidal pattern, in some embodiments, the flat geometry can have any other suitable curved configuration. Typically, the shape of the formed profile can be, but is not limited to, oval, ellipsoidal, circular, or spherical. Better thrombus retention capability can be obtained by uniformly spacing the struts around the circumference. In some other embodiments, the second longitudinal struts can be arranged around the circumference in other ways.

[0099] According to other embodiments, the distal body 3 may have other shapes and forming methods, similar to the description of the rotating body 2 above. In a preferred embodiment, the peaks in the second longitudinal strut of the distal body 3 are fewer than the peaks in the first longitudinal strut of the rotating body 2.

[0100] Due to the structure of the distal body 3, the distal body 3 also exhibits radial expansion and circumferential rotation during its unfolding phase from a contraction structure to an expansion structure.

[0101] The distal body 3 can also be made of shape memory material, preferably a nickel-titanium alloy, and can self-expand from a contracted structure to an expanded structure. Any other biocompatible, hyperelastic metallic material is also acceptable. Once released from the contracted / tightened delivery structure, the distal body 3 can automatically recover its shape. The material can be in various forms, such as wires or tubes. The diameter of the wire or the outer diameter of the tube is typically between 50 micrometers and 250 micrometers. When fabricating the second longitudinal strut 30, any process suitable for forming shape memory materials can be used accordingly.

[0102] In one embodiment, the distal body 3 is made of a circular nickel-titanium alloy wire with a diameter of approximately 80 micrometers. The distal body 3 can also have various lengths and diameters. Typically, the length of the distal body 3 is shorter than that of the rotating body 2. The maximum diameter of the distal body 3 will be appropriately determined to cover an arterial diameter range of 2.0 mm to 6.0 mm. Similar to the rotating body 2, the distal body 3 is “oversized” relative to the blood vessel to be deployed therein to ensure positive pressure engagement with the vessel. Typical oversize amounts can be between 10% and 33%. Therefore, in some embodiments, if the arterial diameter range to be covered is 2.0 mm to 6.0 mm, the maximum diameter range of the shaped profile of the distal body 3 can be 2.2 mm to 8 mm.

[0103] In other embodiments, the distal body 3 can be a well-known structure, such as a spherical mesh structure. When combined with the rotating body according to the invention, it can at least partially solve the problems in existing devices.

[0104] When device 1 is delivered to the desired location for thrombus removal from the cranial artery, the distal body 3 unfolds first within the vessel as it exits the microcatheter first. The distal body 3 acts as a distal embolization protection structure, capturing any emboli that have completely detached from the main thrombus structure and may attempt to move distally into other vessels within the neurovascular network. The distal body 3 functions as an "omnidirectional capture" structure during thrombus removal, ensuring that all thrombus material proximal to the distal body 3 is pushed proximally as the structure is pulled back into the aspiration catheter. The distal body 3 provides a large space between itself and the rotating body 2, allowing the thrombus to infiltrate and be contained within this space during removal.

[0105] In addition to serving as a distal embolization protection structure, the distal body 3 also acts as a means of pushing all thrombus material proximal to it toward the aspiration catheter when the entire structure is pulled proximally. (See reference...) Figure 12The distal body 3, composed of six longitudinal struts 30, provides a denser network structure when viewed axially to ensure its ability to prevent thrombus loss distally is optimized as much as possible. Loose thrombi are more easily removed from the vessel as adhesion to the vessel wall is broken. Once a thrombus detaches from the vessel wall, it is either trapped by the struts of the rotating body 2 or by the much denser network structure of the distal body 3.

[0106] The thrombus removal device may include a push wire connected to the proximal end of a rotating body and a microcatheter with a channel for receiving and thus delivering the distal body, the rotating body, and the push wire.

[0107] For illustrative purposes, the invention has been described above in conjunction with specific embodiments thereof. However, the above illustrative description is not intended to be exhaustive or to limit the invention to the exact forms disclosed.

Claims

1. A thrombus extraction device, comprising: a rotating body formed by a plurality of first longitudinal struts, wherein the first longitudinal struts are fixed only at a proximal end and a distal end, the rotating body assumes an expanded configuration when the rotating body is in a free state, and the rotating body assumes a collapsed configuration when the rotating body is inserted into a catheter; and a distal body connected to a distal end of the rotating body, the distal body assumes an expanded configuration when the distal body is in a free state, and the distal body assumes a collapsed configuration when the distal body is inserted into a catheter; wherein at least a portion of each first longitudinal strut radially expands and circumferentially rotates about a longitudinal axis of the thrombus extraction device during a deployment phase of the rotating body from the collapsed configuration to the expanded configuration, such that the rotating body has a radial expansion and a circumferential rotation.

2. The thrombus extraction device of claim 1, wherein, The plurality of first longitudinal struts have a same geometry as each other and are arranged in a rotationally symmetric manner.

3. The thrombus extraction device of claim 1 or 2, wherein, Each of the plurality of first longitudinal struts is elongated and has a curvature along a longitudinal direction of the rotating body and a curvature in a circumferential direction about the rotating body.

4. The thrombus extraction device of claim 1 or 2, wherein, Each of the plurality of first longitudinal struts can be formed by: providing a straight strut; bending the strut into a flat geometry, i.e. in one plane and having a curvature shape comprising at least one peak along a longitudinal direction of the flat geometry; and drape the flat geometry over a forming mandrel with the longitudinal direction of the flat geometry being parallel to a longitudinal direction of the mandrel.

5. The thrombus extraction device according to claim 4, wherein, The flat geometry comprises 2, 3, or 4 repeating peaks.

6. The thrombus extraction device according to claim 5, wherein, The flat geometry is a sinusoidal or a triangular wave shape.

7. The thrombus extraction device according to claim 4, wherein, The forming mandrel has a circular, elliptical, or polygonal cross-section.

8. The thrombus extraction device of claim 7, the forming mandrel has a uniform cross-section.

9. The thrombus extraction device of claim 7, the forming mandrel is tapered with a larger diameter size at the proximal end and / or the distal end.

10. The thrombus extraction device of claim 1 or 2, wherein, The rotating body is formed by three first longitudinal struts, wherein the plurality of first longitudinal struts are fixed together at the proximal end and the distal end.

11. The thrombus extraction device of claim 1 or 2, wherein, The distal body is formed by a plurality of second longitudinal struts, wherein the second longitudinal struts are fixed only at a first end and a second end.

12. The thrombus extraction device according to claim 11, wherein, The plurality of second longitudinal struts have a same geometry as each other and are arranged in a rotationally symmetric manner.

13. The thrombus extraction device according to claim 11, wherein, Each of the plurality of second longitudinal struts is elongated and has a curvature along a longitudinal direction of the distal body and a curvature in a circumferential direction about the distal body.

14. The thrombus extraction device according to claim 11, wherein, Each of the plurality of second longitudinal struts is formed by: providing a straight strut; bending the strut into a flat geometry, i.e. in one plane and having a curvature shape comprising at least one peak along a longitudinal direction of the flat geometry; and drape the flat geometry over a forming profile with the longitudinal direction of the flat geometry being in the same plane as a longitudinal direction of the forming profile. ​ 15. The thrombus extraction device according to claim 14, wherein, The flat geometry of the second longitudinal strut comprises a peak.

16. The thrombus extraction device according to claim 15, wherein, The flat geometry of the second longitudinal strut is sinusoidal.

17. The thrombus extraction device according to claim 14, wherein, The shaped profile is an ellipsoidal shaped profile.

18. The thrombus extraction device according to claim 14, wherein, The number of second longitudinal struts is greater than the number of first longitudinal struts.

19. The thrombus extraction device according to claim 14, wherein, The distal body is formed of six second longitudinal struts, and the six second longitudinal struts form a spherical space between them in the expanded configuration.

20. The thrombus extraction device according to claim 14, wherein, The plurality of second longitudinal struts are fixed together at first and second ends.

21. The thrombus extraction device according to claim 14, wherein, The number of first longitudinal struts and second longitudinal struts is the same, each of the plurality of first longitudinal struts is integrally formed with a corresponding one of the plurality of second longitudinal struts.

22. The thrombus extraction device according to claim 11, wherein, The plurality of second longitudinal struts are formed of a shape memory material.

23. The thrombus extraction device of claims 1 or 2, wherein, The plurality of first longitudinal struts are formed of a shape memory material.

24. The thrombus extraction device according to claim 22, wherein, The shape memory material is a nickel titanium alloy.

25. The thrombus extraction device according to claim 11, wherein, Each of the plurality of first longitudinal struts and the plurality of second longitudinal struts is a wire having a diameter of 80 microns.

26. The thrombus extraction device of claim 1 or 2, further comprising: A pusher guide wire connected to the proximal end of the rotating body; And a microcatheter having a passage for accommodating the distal body, the rotating body, and the pusher guide wire.

27. The thrombus extraction device according to claim 4, wherein, When the flat geometry is wrapped around the forming mandrel as a cambered surface, the flat geometry wraps the forming mandrel by 180 degrees.

28. The thrombus extraction device of claims 1 or 2, wherein, When the rotating body is pushed out of the catheter and transitions from a contracted configuration to an expanded configuration, at least a portion of each first longitudinal strut rotates by 65 degrees.

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