Intravascular device with guidewire

Abstract

The invention relates to an endovascular device (1) having a stent structure (2), which is present in an expanded state, in which the stent structure is at least temporarily released in a blood vessel, and a compressed state, in which the stent structure is inserted into the blood vessel in a microcatheter, the stent structure (2) having a substantially cylindrical main part (3), wherein the stent structure (2) has at least one connection point (6) to a guidewire (5), and the guidewire (5) extends distally beyond the stent structure (2), and wherein the guidewire extends along a periphery of the stent structure (2). According to an alternative embodiment, the stent structure (2) is connected to a tube (12) through which a guidewire (5) extends distally beyond the stent structure (2). The device (1) according to the invention allows the guide wire (5) and the stent structure (2) to be inserted into the blood vessel together with the microcatheter without the need to exchange midway between the guide wire (5), the microcatheter and the stent structure (2).

Description

[0001] The present invention relates to an intravascular device having a stent structure, which exists in an expanded state and a compressed state. In the expanded state, the stent structure is at least temporarily released in the blood vessel, and in the compressed state, the stent structure is inserted into the blood vessel through a microcatheter, wherein the stent structure has a substantially cylindrical main part.

[0002] Thromboembolic diseases such as myocardial infarction, pulmonary embolism, peripheral thrombosis, organ embolism, etc. are usually triggered by thrombus emboli (hereinafter referred to as: thrombus), i.e., viscoelastic blood clots composed of platelets, fibrinogen, coagulation factors, etc., which adhere to the blood vessels and completely or partially block the blood vessels. Among them, the obstruction of organ arteries leads to the interruption of oxygen and nutrition supply to dependent tissues. After the disorder of functional metabolism accompanied by loss of function, structural metabolism stops soon, causing necrosis (infarction) of affected tissues. The most common organs of the human body affected by this are the heart and the brain. But such changes also affect limb arteries and pulmonary arteries. Venous thrombosis and thromboembolic obstruction also often occur in leg veins and pelvic veins. The disease of thrombotic obstruction of intracranial sinuses may cause severe cerebral hemorrhage due to the disorder of venous return of brain tissue.

[0003] Given the severity of conditions triggered by thromboembolism and the frequency of these disorders, various techniques are known for dissolving or removing thrombi.

[0004] It is known to treat patients with thrombolytic agents (e.g. streptokinase or urokinase) or with anticoagulants, which are used to dissolve thrombi or inhibit thrombus growth. Since these treatment methods are time-consuming in most cases, they are often combined with methods for breaking up or removing thrombi and emboli.

[0005] In addition to open surgical intervention, transluminal or intravascular catheter-guided interventional methods are increasingly used in the prior art because these methods are less invasive. It is therefore known to remove thrombi from the patient's body by means of a suction catheter that generates negative pressure or by mechanical means using a catheter provided with a capture cage, spiral structure or hook, etc., see US 6,245,089 B1; US ​​5,171,233 A1, Thomas E. Meier et al., Stroke, 2002, No. 9, p. 2232.

[0006] A disadvantage of thrombolytic treatment methods is that they are less likely to be successful once the time window has expired. Known transluminal devices also often fail to completely remove the thrombus, and there is also a risk that the thrombus or thrombus fragments will be released and reach smaller vessels in the bloodstream where they are more difficult to access and treat.

[0007] WO 2012 / 156069 A1 discloses a thrombectomy device having a slot which extends in a spiral shape on the side of the device, wherein a retaining clip crosses the slot in a wave-like manner at the proximal end. After the thrombus has been captured, the device is retracted into a microcatheter (suction catheter) and removed from the vascular system together with the thrombus. The thrombectomy device is particularly suitable for removing thrombi from small cavities or highly tortuous vessels, such as cerebral vessels.

[0008] Other intravascular devices are implants which, unlike thrombectomy devices, are not intended to be removed from the vascular system again after the capture of the thrombus, but are intended to remain permanently in the vessel. Such implants are, for example, stents for keeping blood vessels open, in particular after a stenosis (narrowing) in the vessel has been eliminated. The latter can be done with the aid of angioplasty (PTA) and balloon catheters. Typically, stents have a tubular structure and are either laser cut to give a surface consisting of struts with openings between them, or are made of a wire mesh. The stent can be placed at the target site by means of a catheter and expanded there; in the case of self-expanding stents made of shape memory material, this expansion and conformation to the inner wall of the vessel is automatic.

[0009] Another form of implant permanently introduced into a blood vessel is a flow diverter. They are placed in front of the neck of the aneurysm in order to prevent or at least significantly reduce the blood flow into the aneurysm, so that the aneurysm is eventually occluded. Usually, the flow diverter has a higher surface density than the ordinary stents used to keep blood vessels open. An example of a flow diverter is described in the application WO 2008 / 107172 A1.

[0010] Stents or flow-diverting devices can also be used to prevent occlusive devices or embolic agents introduced into the aneurysm from flowing out of the aneurysm. So-called coils, i.e. small spiral coils of wire, are often used as occlusive devices. If these coils enter the bloodstream from the aneurysm, this can lead to serious complications and blockage or damage to more distal vessels. This can be prevented by stents or flow-diverting devices placed in front of the aneurysm. If enough occlusive devices have been introduced into the aneurysm, they get stuck together and thus prevent each other from flowing out of the aneurysm, i.e. after the aneurysm has been completely filled, in some cases there is no need for further covering of the aneurysm neck. The technique of placing an additional intravascular device in front of the aneurysm to prevent the occlusive device from flowing out is also known as "Jail ing".

[0011] Another field of application of intravascular devices is the treatment of vasospasm. Vasospasm is a spasmodic narrowing of a blood vessel. This brings the risk that the blood vessels behind are no longer adequately supplied with blood (ischemia), which can lead to necrosis of tissue supplied by the blood vessels. Especially in the brain area, vasospasm may occur a few days after a subarachnoid hemorrhage (SAH), which is usually the result of an aneurysm rupture. A device for treating vasospasm is known from WO 2017 / 207689 A1, which is essentially a stent structure, but it does not remain permanently in the vascular system, but is placed at the site of the vasospasm and expanded there so as to then retract again. Implants that are permanently retained in blood vessels for the treatment of vasospasm are also conceivable.

[0012] Typically, when introducing an intravascular device, a guidewire is first placed, via which a microcatheter is advanced to the target location. Subsequently, the guidewire is removed so that the intravascular device itself can finally be inserted via the microcatheter. Typically, a guide catheter is also used, via which the microcatheter is first advanced, wherein the distal end of the guide catheter is located proximal to the actual target location, i.e., the microcatheter is advanced beyond the distal end of the guide catheter.

[0013] In principle, this method has proven useful, but it requires multiple work steps and therefore also a certain amount of time. Therefore, in particular in time-critical treatments (e.g. thrombus removal), it is desirable to provide an intravascular device that enables a faster positioning of the device at the target location. Furthermore, it is also desirable to simplify the handling.

[0014] According to the present invention, the purpose of providing a corresponding device is achieved by an intravascular device having a stent structure, which exists in an expanded state and a compressed state, in which the stent structure is at least temporarily released in the blood vessel and in which the stent structure is inserted into the blood vessel in a microcatheter, wherein the stent structure has a generally cylindrical main part, wherein the stent structure has at least one connection point with a guide wire, and the guide wire extends distally beyond the stent structure, wherein the guide wire extends along the periphery of the stent structure.

[0015] The present invention is based on the idea of ​​placing the stent structure and the guide wire together with the microcatheter at the target location in a single step. The guide wire is connected to the stent structure, wherein the guide wire further extends distally beyond the distal end of the stent structure.

[0016] When inserting, it is common practice to introduce the support structure and the installed guide wire into the microcatheter under a compressed state. The placement in the microcatheter is carried out in such a way that the distal end of the guide wire protrudes distally from the microcatheter. For this reason, the intravascular device is usually pushed far enough into the microcatheter. Subsequently, the microcatheter can be advanced distally in the guiding catheter together with the intravascular device in the microcatheter, and finally advanced in the distal direction in the blood vessel itself until the support structure reaches the target position. Then, it is usually released by retracting the microcatheter in the proximal direction under the condition that the position of the intravascular device remains unchanged, or, if necessary, by further advancing the intravascular device in the distal direction under the condition that the position of the microcatheter remains unchanged at the same time. The retraction of the microcatheter and the advancement of the intravascular device can also be combined with each other. Since the guide wire protrudes distally from the microcatheter, the guide wire can further open a path through the vascular system for the microcatheter and the support structure therein. Among them, the advantage of this method is that the replacement between the common guide wire, microcatheter and the last intravascular device in the prior art can be omitted, thereby making the method simpler and more time-saving.

[0017] The guide wire extends along the periphery of the stent structure so that when the stent structure expands, the guide wire itself does not impair its function. For example, when the intravascular device is used to remove a thrombus, the stent structure can penetrate the thrombus without interfering with the guide wire that is still there. The device and the captured thrombus can be retracted together, for example into a suction catheter, while the stent structure is still connected to the guide wire. This also distinguishes the device according to the present invention from the devices known in the prior art, in which, although the device is sometimes also fixed to the insertion wire, the device is precisely released by separating the connection between it and the insertion wire, which is not the case according to the present invention.

[0018] The connection between guide wire and support structure can be configured as fixed, that is, guide wire all remains fixed in rotation and longitudinal displacement relative to support structure. This structure has the advantage of being particularly simple. The fixed connection between support structure and guide wire can be produced, for example, by gluing, welding or soldering. Since guide wire cannot be twisted relative to support structure in this case, if the distal part of guide wire is bent to the side or better along the proximal direction, this is conducive to detection, that is, the device is carefully advanced through the vascular system along the distal direction, wherein the treating doctor must follow the bending of the corresponding blood vessel. In other words, the distal end of guide wire can have a J-shape or a crutch shape. Guide wire basically automatically follows the bending of blood vessel, without the risk of damaging the vessel wall.

[0019] However, it is particularly advantageous to allow a connection mode with freedom of movement between the guide wire and the stent structure. For example, the connection point can be a fixed bearing that allows the guide wire to rotate relative to the stent structure to prevent longitudinal displacement. When advancing the intravascular device and the microcatheter, the treating physician can correspondingly rotate the guide wire to detect the further direction of the blood vessel. In this embodiment, it is also advantageous for the distal portion of the guide wire to have a bend to the side or in the proximal direction to further simplify detection and prevent damage to the inner wall of the blood vessel.

[0020] Finally, according to another advantageous embodiment, the connection point between the support structure and the guide wire is a floating bearing, which allows the guide wire to be displaceable in the longitudinal direction and allows the guide wire to rotate relative to the support structure. In this way, the therapist can not only rotate the guide wire during advancement, so that it can better follow the course of the blood vessel, but also carefully push the guide wire back and forth relative to the support structure and the microcatheter. The displaceability of the guide wire in the longitudinal direction to the proximal and distal sides is usually limited by a stop.

[0021] According to a particularly advantageous embodiment, the stent structure has at least two connection points with the guide wire, wherein one of the connection points is a fixed bearing, which allows the guide wire to rotate relative to the stent structure, and the other connection point is a floating bearing, which allows the guide wire to be displaceable in the longitudinal direction and allows the guide wire to rotate relative to the stent structure, wherein the fixed bearing and the floating bearing are spaced apart from each other in the longitudinal direction. The combination of the fixed bearing and the floating bearing is used to compensate for the change in length of the stent structure that occurs when the stent structure is compressed or expanded. This occurs on the one hand when the stent structure is inserted into the microcatheter, and on the other hand during the release process. The stent structure shortens when it expands during the release process of the stent structure, and the stent structure lengthens when it is compressed during the insertion of the catheter. In order to prevent bending or deformation of the guide wire in this case, two connection points between the guide wire and the stent structure are advantageous, wherein one connection point remains fixed in terms of longitudinal displacement, and the other connection point allows relative longitudinal displacement between the guide wire and the stent structure. Typically, the more distal connection point is configured as a floating bearing and the more proximal connection point is configured as a fixed bearing; however, the opposite configuration is also feasible. For a floating bearing it is also sensible to limit the longitudinal displaceability, in particular by a stop.

[0022] According to an alternative embodiment, an intravascular device with a stent structure is provided, the stent structure exists in an expanded state and a compressed state, in which the stent structure is at least temporarily released in the blood vessel, and in which the stent structure is inserted into the blood vessel in a microcatheter, wherein the stent structure has a substantially cylindrical main part and has at least one connection point connected to a tube, through which a guide wire passes and is placed beyond the stent structure and extends distally thereof. According to this alternative embodiment, the stent structure is therefore not directly connected to the guide wire, but to the tube, through which the guide wire passes. However, in this embodiment, the guide wire still extends distally beyond the stent structure when in use, so that the blood vessel can be detected by means of the guide wire and the guide wire is advanced together with the microcatheter in which the intravascular device is located. The guide wire can be pushed and rotated in the longitudinal direction by the tube, which additionally simplifies the advancement and detection through the vascular system.

[0023] The tube connected to the stent structure may also be referred to as a hypotube. This is generally understood to be a thin tube with an inner cavity or lumen, such as can be used as the proximal part of a catheter. The tube is usually metallic and can be made of, for example, stainless steel or cobalt-chromium alloy.

[0024] In order to increase the flexibility of the tube, it can have slots or notches. These slots or notches are usually introduced into the tube from the outside and have a direction substantially perpendicular to the longitudinal direction. Slots or notches having a diagonal or helical direction to the longitudinal direction are also feasible.

[0025] As in the first embodiment where the stent structure is directly connected to the guide wire, when the stent structure is connected to the tube, the guide wire preferably extends along the periphery of the stent structure so that when the stent structure is expanded, the guide wire itself does not impair its function.

[0026] The guidewire also advantageously has a distal portion that curves laterally or in a proximal direction. This makes it easier for the treating physician to find and navigate the path through the blood vessel without the risk of damaging the vessel.

[0027] Regardless of the embodiment of the present invention and the design of the connection point, whenever a stent structure is mentioned according to the present invention, this should be understood as a generally tubular structure, similar to the structure used in a stent. This applies whether the intravascular device is actually used as a stent in the true sense or as a thrombectomy device, a blood flow guiding device, a device for treating vasospasm or for other purposes. The stent structure has a generally cylindrical main part, which occupies most of the length of the stent structure. The stent structure can be constructed to be open or closed at the proximal and distal ends. Wherein open should be understood as no struts or wires at the corresponding ends of the stent structure, and the struts / wires are limited to the outer circumference (side) of the stent structure. However, in the closed end, the struts or wires are also present in the center of the stent structure. Since there are openings between the struts or wires, even if the distal end is closed, the end is not completely sealed; blood flow can still pass through the opening. At the distal end of the stent structure, as in the main part, it can be generally cylindrical, but different designs are also feasible, such as a radially expanded distal end, which can also be called a trumpet shape.

[0028] The terms "proximal" and "distal" are to be understood such that when the device is inserted, the portion pointing toward the treating physician is referred to as proximal and the portion pointing away from the treating physician is referred to as distal. Thus, the device is usually advanced through the vascular system together with the microcatheter in the distal direction. The term "axial" refers to the longitudinal axis of the device running from proximal to distal, and the term "radial" refers to a plane perpendicular thereto.

[0029] At least in some areas, preferably the whole structure is cylindrical stent structure usually has openings or mesh units distributed on the side of the cylinder. In other words, it is a grid or mesh structure made of pillars, beams or wires, so that a large number of openings / mesh units are produced on the side of the cylinder.

[0030] The support structure consisting of interconnected crossbeams or struts can be produced in a basically known manner by laser cutting; in this case, it is also referred to as a cut structure. In this way, a large number of openings or a network structure is produced in the support structure, wherein the openings are distributed over the circumference of the support structure. Other production methods are also conceivable, such as electroplating or photolithographic production, 3D printing or rapid prototyping.

[0031] Alternatively, the stent structure can also be a mesh structure composed of wires forming a braid. In this case, these wires usually have a spiral orientation along the longitudinal axis, wherein the wires with opposite orientations have an orientation that is staggered up and down at the intersection, so that honeycomb-like openings are formed between the wires. The total number of wires is preferably 8 to 128. The wires forming the mesh structure can be single-strand wires made of metal, but strands can also be provided, i.e. a plurality of wires of small diameter, which together form filaments and are preferably twisted together.

[0032] The term "opening" or "mesh unit" refers to a grid structure, whether or not the opening is isolated from the environment by a membrane, i.e., an opening covered by a membrane is also referred to as an opening. If necessary, the membrane can be applied to the outside or inside of the grid structure. Similarly, it is also feasible to embed the grid structure in the membrane. The membrane can be made of a polymer material, such as polytetrafluoroethylene, polyester, polyamide, polyurethane, polyolefin or polysulfone. Particularly preferred is polycarbonate polyurethane (PCU).

[0033] Compared to a mesh structure consisting of wires, a stent structure consisting of interconnected beams or struts, which is produced in particular by laser cutting, has the advantage that a stent structure consisting of struts is less susceptible to length contraction during expansion than a mesh structure. In the use as a thrombectomy device (a device for removing thrombi and clots from blood vessels), a stent structure consisting of interconnected struts also has the advantage that, with otherwise similar structures, the strut / wire density and the strut / wire strength are the same, such a stent structure exerts a higher radial force than a mesh structure consisting of wires. The reason for this is that the struts have a fixed connection at the intersection, while the wires of the mesh structure usually only have a staggered orientation up and down.

[0034] The struts or wires may have a circular, oval, square, rectangular or trapezoidal cross section, wherein in the case of a square, rectangular or trapezoidal cross section, rounding of the edges is advantageous. Additionally, it is reasonable to electropolish the stent structure to make it smoother and more rounded, thereby reducing trauma. In addition, the risk of adhesion of bacteria or other contaminants is reduced. It is also feasible to use flat struts / wires in the form of thin strips, in particular metal strips.

[0035] The diameter of the stent structure in the freely expanded state is usually in the range of 2mm to 8mm, preferably in the range of 4mm to 6mm. The total length of the stent structure in the expanded state is usually 5mm to 50mm, preferably 10mm to 45mm, more preferably 20mm to 40mm.

[0036] In the case of a stent structure consisting of struts, the stent structure can be cut, for example, from a tube with a wall thickness of 25 μm to 70 μm; in the case of a mesh structure consisting of interwoven wires, the wire thickness is preferably 20 μm to 70 μm. The microcatheter, with which the device can be placed at the target location in a compressed state, has an inner diameter of, for example, 0.4 mm to 0.9 mm.

[0037] Advantageously, the stent structure has a tapered proximal portion near the cylindrical main portion, which tapers to a connection point with a guide wire or a tube on the periphery of the stent structure. Correspondingly, the guide wire can correspondingly have a direction just in the longitudinal direction of the device, i.e., the guide wire extends along the periphery of the stent structure. In this case, the stent structure periphery should be understood as the circumferential surface of the stent structure that is called the side. The advantage of this eccentric arrangement of the guide wire is also that the guide wire is prevented from damaging the function of the intravascular device and the stent structure or hindering blood flow in this way. In addition, the eccentric arrangement of the guide wire facilitates the device to be retracted into the microcatheter (in this case where it is confirmed to be necessary) or the suction catheter.

[0038] Advantageously, the distal portion of the guide wire has a bend that is as uniform as possible to the side or in the proximal direction. This makes it easier for the guide wire to follow narrow, highly curved blood vessels. Therefore, the distal end of the guide wire is not simply protruding sharply in the distal direction, but has a rounding, such as a J-shape. The bend of the distal portion of the guide wire is particularly important when there is little or no freedom of movement between the guide wire and the support structure, i.e., in particular when there is a fixed connection between the guide wire and the support structure.

[0039] It is also advantageous that the guide wire has a certain flexibility, particularly in its distal portion. This can be ensured by a corresponding material selection. For example, a shape memory metal with superelastic properties, such as a nickel-titanium alloy, can be used as the material of the guide wire. Such alloys are known as nitinol. Other preferred materials for the guide wire are stainless steel or cobalt-chromium alloys. In particular, the distal portion of the guide wire can also be made of a particularly flexible material (e.g. a shape memory metal), while the more proximal region can be made of another material (e.g. stainless steel).

[0040] It is also advantageous to configure at least part of the distal portion of the guidewire to be visible to X-rays. This helps the treating physician to track the advancement of the guidewire in the X-ray image, and thus the advancement of the stent structure and the microcatheter. For example, parts of the guidewire may have platinum or platinum-iridium markings, or may also have a gold coating.

[0041] Suitably, the stent structure is self-expandable so that it automatically assumes an expanded state after being released from the microcatheter. To ensure this, the stent structure can be constructed in particular from a material having shape memory properties or at least contain such a material. Nickel-titanium alloys such as nitinol are also suitable for this. However, polymers or other alloys having shape memory properties, such as nickel-titanium-chromium or nickel-titanium-copper alloys, are also conceivable. It is also feasible to use cobalt-chromium alloys or cobalt-chromium-nickel alloys.

[0042] The cylindrical main part is usually composed of a plurality of mesh units distributed on its circumference, which are open in the radial direction. In other words, the cylindrical main part, but usually the entire stent structure, has a grid or mesh structure constructed by struts or wires, wherein there are mesh units between the struts or wires.

[0043] The mesh cells produced in the stent structure can be completely closed, i.e. surrounded by struts or wires without interruption (so-called "closed-cell design"). An "open-cell design" is also possible, in which at least some of the struts / wires have interruptions, so that the mesh cells composed of the struts / wires are at least partially open, i.e. not completely closed. This open-cell design has greater flexibility, which can be advantageous in highly tortuous blood vessels. On the other hand, the retraction of the device is limited in the open-cell design.

[0044] It is also possible that the stent structure or the cylindrical main part is provided with a slot which extends helically on at least part of the side of the stent structure or along at least part of the side of the stent structure in the longitudinal direction (i.e. substantially parallel to the longitudinal axis). In this case, a single strut or wire can span the slot in order to influence the radial force trend. A corresponding thrombectomy device with a continuous slot parallel to the longitudinal axis is disclosed in WO 2009 / 105710A1, and a device with a helical slot and a fixing clip at the proximal end of the stent structure is disclosed in WO 2012 / 156069A1.

[0045] In order to facilitate the observation of the insertion process by the treating physician, it is reasonable to provide at least some areas of the intravascular device with X-ray visible markings. X-ray visible markings can be made, for example, of platinum, palladium, platinum iridium, tantalum, gold, tungsten or other X-ray visible metals. For example, X-ray visible / X-ray opaque spiral structures can be arranged at various points of the device. It is also feasible to provide the stent structure, in particular the struts or wires of the stent structure, with a coating made of X-ray visible material, such as a gold coating. The coating can, for example, have a thickness of 1 μm to 6 μm. The coating with X-ray visible material does not have to cover the entire stent structure; the coating is particularly important in the area where the stent structure expands towards the inner wall of the blood vessel (i.e., essentially in the cylindrical main part of the stent structure) so that the expansion of the stent structure can be observed. However, even when an X-ray visible coating is provided, it may be reasonable to additionally arrange one or more X-ray visible markings at the device (in particular at the distal end of the stent structure).

[0046] An additional option is to use struts or wires made of metals with shape memory properties, in particular corresponding nickel-titanium alloys, which at least partially have a platinum core. Such struts / wires are known as DFT wires (DFT=drawn filled tubing). In this way, the advantageous properties of nickel-titanium on the one hand (i.e. shape memory properties) and the advantageous properties of platinum on the other hand (i.e. X-ray visibility) are combined.

[0047] At the proximal and distal ends of the stent structure, there may be loose struts or wire ends, but they should preferably be constructed to be non-traumatic in order to avoid damaging the blood vessel. For example, the non-traumatic design of the ends can be achieved by rounding. Another possibility is to allow the struts or wires to form a ring at one or both ends of the stent structure and to guide the ring back into the stent structure. Correspondingly, the ends of the stent structure no longer have free struts or wire ends, thus reducing the risk of injury to the vessel wall.

[0048] In particular, the intravascular device according to the present invention can be a device for removing a thrombus from a blood vessel. Such a device is placed in a microcatheter at the location of the thrombus to be removed and released from the microcatheter there, whereupon the stent structure of the device expands into the thrombus and receives the thrombus therein. The intravascular device with the thrombus captured is then retracted, usually into a suction catheter whose inner diameter is larger than that of the microcatheter, in order to prevent the thrombus or a portion of the thrombus from being "squeezed out" of the stent structure when the stent structure is compressed. At the same time, any detached thrombus fragments can be sucked out.

[0049] The invention is particularly suitable for use in thrombectomy devices, since the removal of a thrombus that may cause an ischemic stroke is time-critical. According to the invention, valuable time can be saved by omitting several sequential steps of changing between a guidewire, a microcatheter and a thrombectomy device, namely in particular introducing the microcatheter and the thrombectomy device into the vessel simultaneously with the guidewire. Correspondingly, recanalization can be performed more quickly. Since the guidewire extends along the periphery of the stent structure, it has little influence on the effectiveness of the in situ thrombectomy device. After the thrombus has been captured, the entire thrombectomy device together with the guidewire is then removed from the vascular system, so that generally there is no need to separate the guidewire from the thrombectomy device.

[0050] However, the intravascular device according to the invention may also be an implant, in particular a stent for keeping a blood vessel open, a blood flow guiding device for inhibiting blood flow into an aneurysm or a stent intended to prevent an occlusive device from flowing out of an aneurysm. Another possible use is as a device for treating vasospasm, wherein the treatment may be based in particular on a temporary or permanent expansion of the stent structure (see, for example, WO 2017 / 207689 A1) or on the application of electrical, high-frequency or ultrasound pulses (see WO 2018 / 046592 A1).

[0051] In particular, in the case of implants, it is necessary to be able to separate the stent structure so that it can remain in the blood vessel. Preferably, the stent structure is provided with the separability of the guide wire or tube so that the guide wire / tube can be retracted from the vascular system while the stent structure remains at the target position. In this way, the influence of the guide wire on the function of the stent structure is eliminated. Correspondingly, the connection point between the guide wire / tube and the stent structure should be constructed to be separable, wherein various separation mechanisms are known in the prior art, in particular electrolytic separation, mechanical separation, thermal separation and chemical separation options. Separability can also be reasonable for intravascular devices that are actually set up to be taken out of the vascular system again, in particular thrombectomy devices and devices for treating vascular spasms, that is, when the retraction of the device during treatment proves to be problematic and the doctor decides to leave the device in the blood vessel.

[0052] The detachment points for separating the support structure are preferably electrolytically corrodible detachment points. In this case, the detachment points are at least partially dissolved by applying a voltage to the detachment points by means of a voltage source. In electrolytic detachment, the detachment points are electrolytically corroded by applying a voltage, so that the support structure is detached from the guide wire. This is usually direct current, where a low current intensity (<3mA) is sufficient. The detachment points are usually made of metal, and when a voltage is applied, an anode is formed, at which oxidation of the metal and therefore dissolution of the metal occurs.

[0053] In order to avoid anodic oxidation of the stent structure, it can be electrically isolated from the detachment point and the guide wire. Electrolytic detachment of implants is well known in the prior art, for example from occlusive coils for blocking aneurysms, see for example WO 2011 / 147567 A1. The principle is based on the fact that when a voltage is applied, the detachment points made of a suitable material, in particular a metal, provided for this purpose usually undergo at least a sufficient degree of dissolution by anodic oxidation so that the area of ​​the device located distal to the corresponding detachment point is released. The detachment point can be made, for example, of stainless steel, magnesium, a magnesium alloy or a cobalt-chromium alloy. A particularly preferred magnesium alloy was developed by the company MeKo from Sarstedt, Germany. (See WO 2013 / 024125 A1). It is an alloy made of magnesium and mainly lanthanides, in particular dysprosium. Another advantage of using magnesium and magnesium alloys is that the retention of magnesium residues in the body is not a physiological problem.

[0054] Although the detachment point serves as an anode, the cathode can be positioned, for example, on the body surface. Alternatively, another area of ​​the device can also form a cathode. Of course, the detachment point must be connected to the voltage source in a conductive manner accordingly. The guide wire itself can be used as a conductor. Since the corrosion current generated in the cathode placed on the body surface is controlled by the area of ​​the cathode, the area of ​​the cathode should be significantly larger than the area of ​​the anode. To some extent, the detachment speed can be controlled by adjusting the ratio of the cathode area to the anode area. Therefore, the device according to the present invention can also include a voltage source and, if necessary, an electrode that can be placed on the body surface.

[0055] As an alternative to the breakaway point of electrolytic dissolution, other breakaway points known in the prior art can also be used, in particular breakaway points of mechanical, thermal or chemical separation. In the case of mechanical breakaway, there is usually a form, force or friction lock, which is released when the support structure is released, so that the support structure is separated from the guide wire or tube. In the case of a thermal breakaway point, the connection can be released by heating the breakaway point, and the breakaway point becomes soft or melts so that separation occurs. Finally, chemical separation is also feasible, wherein the separation is caused by a chemical reaction at the breakaway point.

[0056] Different types of separation, such as electrolytic separation and mechanical separation, can also be combined with each other. In this case, a mechanical connection is established between the units, in particular via a form fit, which exists until the element maintaining the mechanical connection is electrolytically corroded.

[0057] At least part of the stent structure may be coated with a coating that prevents platelet adhesion. Such an anti-thrombotic coating may have a functional layer, wherein the functional layer comprises at least one sugar alcohol and / or is formed by oligomerization or polymerization of monosaccharides functionalized with polymerizable groups. Such an anti-thrombotic coating is disclosed in WO 2018 / 210989 A1.

[0058] The device according to the invention can be used in particular in the neurovascular area, but use in the cardiovascular or peripheral area is also possible.

[0059] In addition to the intravascular device, the present invention also relates to a method for inserting an intravascular device according to the present invention into a blood vessel, wherein the device is inserted into a microcatheter and placed so that the distal end of the guide wire protrudes distally from the microcatheter, and the microcatheter together with the intravascular device in the microcatheter is advanced in the blood vessel in a distal direction. Typically, before the intravascular device is advanced to the target location together with the microcatheter, a relatively large-caliber guide catheter is first used, and a small-caliber microcatheter is further advanced in a distal direction through the guide catheter. For example, in neurovascular applications, advancement can be made from the groin to the carotid artery by means of a guide catheter, and further advancement can only be made with the microcatheter.

[0060] Furthermore, the present invention also relates to a combination of an intravascular device and a microcatheter, wherein the intravascular device is placed in the microcatheter in such a manner that a distal end of a guidewire protrudes distally from the microcatheter.

[0061] Finally, the invention also relates to the use of the device according to the invention for removing a thrombus from a blood vessel or a corresponding method.

[0062] Unless the context dictates otherwise, all descriptions of features of the invention relate respectively to all embodiments, in particular to the first embodiment in which the stent structure is connected to the guidewire via a connection point and to an alternative embodiment in which there is a connection point to a tube.

[0063] The present invention is explained in detail with reference to the embodiments shown in the drawings. It should be noted that the drawings show preferred implementation variants of the present invention, but the present invention is not limited thereto. In general, the present invention includes any combination of technical features listed in the claims or described in the specification as relevant to the present invention, where technically reasonable.

[0064] in:

[0065] Figure 1 The device according to the invention according to a first embodiment is shown in a side view;

[0066] Figure 2 The device according to the invention according to a second embodiment is shown in a side view;

[0067] Figure 3 shows a device according to the invention according to a third embodiment in a side view; and

[0068] Figure 4The device according to the invention according to an alternative embodiment is shown in a side view.

[0069] exist Figure 1 In the figure, a first embodiment of an intravascular device 1 according to the present invention is shown in a side view. The intravascular device 1 is used to capture thrombi and mainly consists of a stent structure 2 and a guide wire 5. The stent structure 2 is shown in an expanded state, and the guide wire 5 extends along the periphery of the side of the stent structure 2. The guide wire 5 and the stent structure 2 are connected to each other via a connection point 6, wherein in the present embodiment, the connection point 6 represents a fixed connection.

[0070] The stent structure 2 has a cylindrical main part 3 and a proximal part 4 that tapers toward the periphery of the stent structure 2, wherein the struts of the stent structure 2 lead to a connection point 6 with a guide wire 5. The struts of the stent structure 2 constitute a large number of mesh units 7 distributed on the side of the stent structure, which are open in the radial direction so that they can penetrate the thrombus when expanded. The guide wire 5 protrudes significantly beyond the stent structure 2 distally to achieve its function of guiding the device 1 through the vascular system. Among them, the distal part 8 of the guide wire 5 is designed to be J-shaped to further simplify detection and minimize the risk of damaging the blood vessel. In order to visualize the insertion and release process, the stent structure 2 is provided with an X-ray visible marker 9 at its distal end.

[0071] Figure 2 2 shows a second embodiment of the invention. In contrast to the first embodiment, the connection point 6 is designed here as a fixed bearing, which allows the guide wire 5 to rotate relative to the support structure 2. This further simplifies the insertion of the intravascular device 1 into the vascular system. Here, too, the guide wire 5 protrudes significantly beyond the support structure 2 in the distal direction and has a distal portion 8 that is bent to the side.

[0072] at last, Figure 3 A third embodiment of the invention is shown. Here, the connection point 6 is designed as a floating bearing, which not only enables a rotation of the guide wire 5 relative to the support structure 2, but also enables a limited displacement in the longitudinal direction. The longitudinal displaceability is indicated by the arrow 11 and is limited by two stops 10. The additional degree of freedom provides the treating physician with additional possibilities when inserting and advancing the intravascular device 1 in the vascular system.

[0073] Figure 4An alternative embodiment of the invention is shown, in which the support structure 2 is not connected to the guide wire 5 at the connection point 6, but to a tube 12, wherein the guide wire 5 passes through the tube 12 and extends distally beyond the support structure 2. The guide wire 5 can rotate in the tube 12 and can be displaced in the longitudinal direction. In this embodiment as well, the intravascular device 1 is placed in a microcatheter (not shown here) so that the guide wire 5 protrudes from the microcatheter in the distal direction, so that the guide wire 5 finds its way through the blood vessel and makes detection possible.

Claims

1. An intravascular device having a stent structure (2), said stent structure existing in an expanded state, in which the stent structure is at least temporarily released in a blood vessel, and in a compressed state, in which the stent structure is inserted into the blood vessel in a microcatheter, wherein the stent structure (2) has a substantially cylindrical main portion (3), It is characterized in that The stent structure (2) has at least one connection point (6) to a guide wire (5), and the guide wire (5) extends distally beyond the stent structure (2), wherein the guide wire extends along the periphery of the stent structure (2).

2. The intravascular device according to claim 1, characterized in that The connection point (6) between the support structure (2) and the guide wire (5) is a fixed bearing, which allows the guide wire (5) to rotate relative to the support structure (2).

3. The intravascular device according to claim 1, characterized in that The connection point (6) between the support structure (2) and the guide wire (5) is a floating bearing which allows the displaceability of the guide wire (5) in the longitudinal direction and allows the self-rotation of the guide wire (5) relative to the support structure (2).

4. The intravascular device according to claim 3, characterized in that The displaceability of the guide wire (5) in the proximal and distal directions along the longitudinal direction is limited by a stop (10).

5. The intravascular device according to any one of claims 1 to 4, characterized in that The support structure (2) has at least two connection points (6) with the guide wire (5), one of which is a fixed bearing, which allows the guide wire (5) to rotate relative to the support structure (2), and one of which is a floating bearing, which allows the guide wire (5) to be displaceable in the longitudinal direction and allows the guide wire (5) to rotate relative to the support structure (2), wherein the fixed bearing and the floating bearing are spaced apart from each other in the longitudinal direction.

6. An intravascular device having a stent structure (2), said stent structure existing in an expanded state, in which the stent structure is at least temporarily released in a blood vessel, and in a compressed state, in which the stent structure is inserted into the blood vessel in a microcatheter, wherein the stent structure (2) has a substantially cylindrical main part (3), characterized in that The stent structure (2) has at least one connection point (6) to a tube (12), a guide wire (5) passing through the tube (12) and being positioned beyond the stent structure (2) and extending distally therefrom.

7. The intravascular device according to claim 6, characterized in that The guide wire extends along the periphery of the stent structure (2).

8. The intravascular device according to claim 6 or 7, characterized in that: The tube (12) is made of metal.

9. The intravascular device according to any one of claims 6 to 8, characterized in that The tube (12) has a slot or notch, which has a direction substantially perpendicular or diagonal to the longitudinal direction, and which increases the flexibility of the tube (12).

10. The intravascular device according to any one of claims 1 to 9, characterized in that The stent structure (2) has a tapered proximal portion (4) proximal to the cylindrical main portion (3), which tapers toward a connection point (6) with the guide wire (5) or the tube (12) located on the periphery of the stent structure (2).

11. The intravascular device according to any one of claims 1 to 10, characterized in that The guide wire (5) has a distal portion (8) which is bent laterally or in a proximal direction.

12. The intravascular device according to any one of claims 1 to 11, characterized in that At least part of the distal portion (8) of the guidewire (5) is configured to be X-ray visible.

13. The intravascular device according to any one of claims 1 to 12, characterized in that The stent structure (2) is configured to be self-expandable and automatically assumes the expanded state after being released from the microcatheter.

14. The intravascular device according to any one of claims 1 to 13, characterized in that The intravascular device (1) is a device for removing a thrombus from a blood vessel.

15. The intravascular device according to any one of claims 1 to 13, characterized in that The intravascular device (1) is an implant.

16. The intravascular device according to any one of claims 1 to 15, characterized in that The connection point (6) between the support structure (2) and the guide wire (5) or the tube (12) is configured to be electrolytically, mechanically, thermally or chemically separable.

17. A combination of an intravascular device (1) according to any one of claims 1 to 16 and a microcatheter, characterized in that: The intravascular device (1) is placed in the microcatheter in such a manner that the distal end of the guide wire (5) protrudes distally from the microcatheter.

18. A method for inserting an intravascular device (1) according to any one of claims 1 to 16 into a blood vessel, characterized in that: The intravascular device (1) is inserted into a microcatheter and positioned in such a manner that the distal end of the guide wire (5) protrudes distally from the microcatheter, and the microcatheter together with the intravascular device (1) therein is advanced in the blood vessel in a distal direction.

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