Intravascular device having a guidewire

Abstract

The present invention relates to an intravascular device (1) having a stent structure (2), the stent structure being provided in an expanded state that is at least temporarily released within a blood vessel and a compressed state that is introduced into the blood vessel within a microcatheter, the stent structure (2) having a substantially cylindrical main portion (3), the stent structure (2) having at least one connection location (6) with a guide wire (5), the guide wire (5) extending distally from the stent structure (2), the guide wire (5) being passed along the perimeter of the stent structure (2). According to an alternative embodiment, the stent structure (2) is connected to a tube (12), and through the tube (12), the guide wire (5) extends distally from the stent structure (2). The device (1) according to the present invention enables the guide wire (5) and the stent structure (2) to be simultaneously introduced into the blood vessel together with the microcatheter, during which there is no need for a change to occur between the guide wire (5), the microcatheter, and the stent structure (2).

Description

Technical Field

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

Background Art

[0002] Thromboembolic diseases such as myocardial infarction, pulmonary embolism, peripheral thrombosis, and organ embolism are typically caused by thromboembolism (hereinafter referred to as thromboembolism), that is, thromboembolism is a viscoelastic thrombus composed of platelets, fibrinogen, coagulation factors, etc., which clogs blood vessels and completely or partially occludes blood vessels. Occlusion of the arteries of organs causes interruption of the supply of oxygen and nutrients to the dependent tissues. Functional and metabolic disorders accompanied by loss of function are followed by cessation of structural metabolism and destruction (infarction) of the affected tissues after a short period of time. The most commonly affected organs in humans are the heart and brain. However, such changes also affect the arteries of the extremities and the pulmonary artery. Venous thrombosis and thromboembolism also occur more frequently in the lower extremities and pelvic veins. The clinical picture of thrombo-occlusion in the cranial cavity may cause severe cerebral hemorrhage due to obstruction of the venous drainage of brain tissue.

[0003] Considering the severity of the clinical picture caused by thromboembolism and the frequency of these diseases, various techniques for dissolving or removing thrombi are known.

[0004] For example, it is known to treat patients with thrombolytic agents such as streptokinase or urokinase, or anticoagulants, to dissolve thrombi or inhibit thrombus growth. Since these treatments usually take time, they are often combined with methods for decomposing or removing thrombi and emboli.

[0005] In addition to surgical procedures involving incisions, transcatheter or endovascular catheter-guided interventional therapies are increasingly being used due to their lower invasiveness. For example, it is known to remove a thrombus from a patient's body by means of a suction catheter that generates compression, or mechanically by means of a catheter equipped with a catch basket, coil, hook, etc. (see U.S. Patent Nos. 6,245,089 B1 and 5,171,233 A1, Thomas E. Meier et al., Stroke 2002(9), 2232).

[0006] The drawback of thrombolytic therapy is that it is mostly unsuccessful once the time frame has passed. Even known transcatheter devices often cannot completely remove a thrombus, and there is also a risk that the thrombus and its fragments are released and migrate into smaller intracavitary blood vessels in the bloodstream, where access and treatment become more difficult.

[0007] WO 2012 / 156069 A1 discloses a thrombus removal device having slots spirally extending on an outer surface of the device, with a clamping bracket stretching the slots to undulate at the proximal end. Once a thrombus is captured, the device is withdrawn into a microcatheter (aspiration catheter) and removed from the vascular system along with the thrombus. This thrombus removal device is particularly suitable for removing thrombi from small cavities in the brain or highly tortuous blood vessels.

[0008] Unlike other intravascular devices, which are not intended to be removed from the vasculature after a thrombus has been captured but rather are implants intended to remain permanently within the blood vessel, such implants are, for example, stents that are used to keep the blood vessel open, particularly after the removal of a stenosis (narrowing) of the blood vessel. Removal of a blood vessel stenosis can be accomplished using angioplasty (PTA) and a balloon catheter. Typically, a stent has a tubular structure and is either laser cut to form a surface of sutures with openings therebetween or is made of a wire mesh. A stent is delivered to a target location through a catheter and expanded there, although in the case of a self-expanding stent made of a shape memory material, this expansion and placement against the inner wall of the blood vessel are done independently.

[0009] Another type of implant that is permanently inserted into the blood vessel is a flow diverter. These are placed in front of the neck of an aneurysm to prevent or at least significantly reduce the inflow of blood into the aneurysm so that ultimately the aneurysm disappears. Generally, flow diverters have a higher surface density than normal stents in order to keep the blood vessel open. Examples of flow diverters are described in International Publication No. WO 2008 / 107172 A1.

[0010] Stents, or flow diverters, can also be used to prevent an occluding substance or embolus introduced into an aneurysm from exiting the aneurysm. Coils, i.e., small wire coils, are often used as occluding agents. If these enter the bloodstream from the aneurysm, this can potentially cause serious complications and further occlusion or damage to blood vessels located more distally. This is prevented by a stent or flow diverter placed in front of the aneurysm. When a sufficient number of occluding agents are inserted into the aneurysm, they intertwine with each other and prevent each other from exiting the aneurysm, i.e., when the aneurysm is completely occluded, there is no longer a need to further cover the neck of the aneurysm. The technique of placing an additional intravascular device in front of the aneurysm to prevent occlusion leakage from the aneurysm is also known as "jailing".

[0011] Another application area of intravascular devices is the treatment of vasospasm. Vasospasm is a spasm-like contraction of blood vessels. This is associated with the risk that subsequent blood vessels will no longer be adequately supplied with blood (ischemia), which can in turn cause necrosis of the tissues supplied by the blood vessels. In particular, in the area of the brain, vasospasm can be caused several days after a subarachnoid hemorrhage (SAH), which is often the result of the rupture of an aneurysm. Devices for the treatment of vasospasm are known from International Patent Application No. 2017 / 207689A1, which are substantially stent structures, but do not remain permanently in the vascular system, but are introduced into the site of vasospasm, where they are expanded and then withdrawn again. Implants that remain permanently in the blood vessels for the treatment of vasospasm are also considered.

[0012] Generally, the procedure for inserting an intravascular device includes first placing a guide wire over which a microcatheter is advanced to reach the target position. The guide wire is then removed and the intravascular device itself can be inserted through the microcatheter. Usually, a guide catheter is also used, through which the microcatheter is first advanced, with the distal end of the guide catheter being proximal to the actual target position, i.e., the microcatheter is advanced beyond the distal end of the guide catheter.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Non-Patent Document

[0014]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0015] In principle, this method has proven its value, but some steps are required and thus a certain amount of time is needed. In particular, in time-critical treatments such as thrombus removal, it is desirable to have an intravascular device that enables rapid positioning of the device at the target site. Easy handling would also be desirable.

Means for Solving the Problems

[0016] The object of providing a corresponding device is achieved according to the present invention by an intravascular device having a stent structure that exists in an expanded state that is at least temporarily released intravascularly and a compressed state that is introduced intravascularly within a microcatheter. The stent structure has a substantially cylindrical main portion. The stent structure has at least one junction with a guide wire. The guide wire extends distally beyond the stent structure. The guide wire extends along the outer periphery of the stent structure.

[0017] The present invention is based on the idea of transporting the stent structure and the guide wire to the target position in a single procedure together with a microcatheter. The guide wire is connected to the stent structure and extends further distally than the distal end of the stent structure.

[0018] A typical procedure for insertion is to insert a stent structure with a guide wire attached in a compressed state into a microcatheter. Placement into the microcatheter is performed such that the distal end of the guide wire projects distally from the microcatheter. Typically, the intravascular device is inserted into the microcatheter as far as possible. Next, the microcatheter is advanced into a guide catheter together with the intravascular device within the microcatheter and ultimately advanced distally into the vasculature itself until the stent structure reaches the target location. Thereafter, release is typically performed by retracting the microcatheter proximally while maintaining the position of the intravascular device, and release can also be performed by advancing the intravascular device distally while maintaining the position of the microcatheter, if necessary. It is also possible to combine retraction of the microcatheter and advancement of the intravascular device. The fact that the guide wire projects distally from the microcatheter means that the guide wire can still guide the microcatheter and the stent structure within it through the vasculature. The advantage of this method is that it is a simpler and less time-consuming method as it does not generally require switching of the guide wire, microcatheter, and intravascular device as in the prior art.

[0019] When the stent structure is expanded, the guide wire is passed along the outer periphery of the stent structure so that its function is not impeded by the guide wire itself. For example, when an intravascular device is used to remove a thrombus, the stent structure can penetrate the thrombus without interfering with the guide wire that is still in place. The device can also be withdrawn, for example, together with a captured thrombus, into an aspiration catheter, but the stent structure maintains its connection to the guide wire. Thus, the device according to the present invention is distinguished from devices known in the prior art where the device is fixed to the insertion wire but is precisely released by separating the connection between the device and the insertion wire (this is not the case in the examples according to the present invention).

[0020] The connection between the guide wire and the stent structure can be fixed, i.e., the guide wire maintains a fixed state with respect to the stent structure with respect to rotation and longitudinal displacement. Such a structure has the advantage of being particularly simple. The fixed connection between the stent structure and the guide wire can be created, for example, by adhesion, welding, or soldering. In this case, since the guide wire cannot be twisted with respect to the stent structure, it is advantageous for probing, i.e., carefully advancing the device distally through the vasculature, and the treating physician needs to follow the bends of each blood vessel when the distal portion of the guide wire is bent laterally or, even better, proximally. In other words, the distal end of the guide wire can have a J-shaped or cane-like shape. Thus, the guide wire substantially automatically follows the bends within the blood vessel without the risk of damage to the vessel wall.

[0021] However, a connection between the stent structure and the guide wire that provides freedom of movement between the stent structure and the guide wire is particularly advantageous. For example, the connection point can be a fixed bearing that allows the guide wire to rotate with respect to the stent structure but prevents longitudinal displacement. When advancing the intravascular device and the microcatheter, the treating physician can appropriately rotate the guide wire to probe the further path of the blood vessel. In this embodiment, it is also advantageous for the distal portion of the guide wire to have a bend in the lateral or proximal direction, which simplifies the probing further and prevents damage to the inner wall of the blood vessel.

[0022] Finally, according to a further advantageous embodiment, the connection point between the stent structure and the guide wire is a floating bearing that allows the guide wire to be longitudinally displaced and rotated with respect to the stent structure. In this way, the treating physician can not only rotate the guide wire during advancement to better follow the path of the blood vessel, but also carefully push the stent structure and the microcatheter back and forth. Typically, the longitudinal displacement of the guide wire is limited by stop portions proximally and distally.

[0023] According to a particularly advantageous embodiment, the stent structure has at least two connection positions with the guide wire, one connection position being a fixed bearing that enables the guide wire to rotate relative to the stent structure, and one connection position being a floating bearing that enables longitudinal displacement of the guide wire and rotation of the guide wire relative to the stent structure, the fixed bearing and the floating bearing being spaced apart from each other in the longitudinal direction. The combination of the fixed bearing and the floating bearing is used to compensate for changes in the length of the stent structure that occur when the stent structure is compressed or expanded. This applies both when the stent structure is inserted into the microcatheter and when it is released. The expansion upon release of the stent structure causes shortening, and the compression upon insertion into the catheter causes elongation of the stent structure. In such a relationship, two connection positions between the guide wire and the stent structure are advantageous, one maintaining a fixed state with respect to longitudinal displacement and the other enabling relative longitudinal displacement between the guide wire and the stent structure. Typically, the more distal connection position is designed as a floating bearing and the more proximal connection position is designed as a fixed bearing, although the reverse configuration is also possible. With regard to the floating bearing, again, it is recommended to use stops, in particular, to limit longitudinal displacement.

[0024] According to an alternative embodiment, there is provided an intravascular device having a stent structure that exists in an expanded state that is at least temporarily released within a blood vessel and a compressed state that is introduced into the blood vessel within a microcatheter. The stent structure has a substantially cylindrical main portion and at least one connection position with a tube through which a guide wire extends. Through this tube, the guide wire is carried to a position that extends more distally than the stent structure. According to this alternative embodiment, the stent structure is thus not directly connected to the guide wire, but is connected to a tube through which the guide wire passes through a cavity. However, in this embodiment, the guide wire also extends in a distal direction beyond the stent structure during use, and with the assistance of the guide wire, it is possible to probe the blood vessel and advance the guide wire together with the microcatheter in which the intravascular device is disposed. The guide wire can be moved and rotated longitudinally through the tube, which further facilitates its progression and probing through the vascular system.

[0025] The tube connected to the stent structure, which may also be referred to as a hypo-tube. This is generally understood to mean a thin tube having an internal cavity or lumen and can be used as the proximal portion of the catheter. The tube is typically made of metal and can be made of, for example, stainless steel or a cobalt-chromium alloy.

[0026] To increase the flexibility of the tube, the tube can have slots or notches. These are typically inserted into the tube from the outside and passed through substantially orthogonally to the longitudinal direction. Slots or notches passed through diagonally in the lateral direction or spirally are also possible.

[0027] Similar to the first embodiment in which the stent structure is directly connected to the guide wire, when the stent structure is connected to the tube, the guide wire is preferably passed along the periphery of the stent structure, so that even when the stent structure expands, its function is not impaired by the guide wire itself.

[0028] The guide wire then, conveniently, has a distal portion that is bent laterally or proximally. This makes it easier for the treating physician to find a path through the blood vessel and probe through it without risking damaging the blood vessel.

[0029] Regardless of the embodiments of the present invention and the configuration of the connection positions, when referring to the stent structure according to the present invention, this is understood to mean a substantially tubular structure of the kind that is used in a similar manner in a stent. This applies regardless of whether the intravascular device is actually used as a stent in the strict sense, or is used for thrombus removal, flow diverting, treatment of vasospasm, or other purposes. The stent structure has a substantially cylindrical main portion that constitutes most of the length of the stent structure. The stent structure can be either open or closed at the proximal and distal ends. Being open means that there are no sutures or wires at each end of the stent structure, and the sutures / wires are limited to the outer circumference (outer surface) of the stent structure. On the other hand, at the closed end, there are also sutures or wires in the center of the stent structure. Since there are openings between the sutures or wires, even if the distal end is closed, this end is not completely sealed, and blood can still flow through the openings. At the distal end of the stent structure, it can be substantially cylindrical like the main portion, but different designs are possible, for example, the distal end has a radially expanded shape, which can also be called a trumpet shape.

[0030] The terms "proximal" and "distal" are understood in the sense that the portion facing the treating physician when inserting the device is called "proximal", and the portion away from the treating physician is called "distal". Thus, the device typically advances distally through the vasculature together with a microcatheter. The term "axis" refers to the longitudinal axis of the device passing from proximal to distal, and the term "radial direction" refers to the plane perpendicular to this.

[0031] The stent structure is cylindrical in at least some regions and preferably has, as a whole, openings or cells that are generally distributed on the cylindrical peripheral surface. In other words, it is a grid or mesh structure composed of sutures, bars, or wires, whereby a large number of openings / cells are formed on the surface of the cylinder.

[0032] A stent structure composed of interconnected bars or sutures can be generated by laser cutting in a manner known in principle, and in this context, it is also called a cut structure. In this way, a large number of openings or mesh structures are generated within the stent structure, and the openings are distributed on the outer periphery of the stent structure. Other manufacturing methods are also conceivable, such as electroplating or lithographic manufacturing, 3D printing, or rapid prototyping.

[0033] Alternatively, the stent structure can also be a mesh structure made of wires that form a braid. Typically, the wires are passed spirally along the longitudinal axis, and the wires passed in the opposite direction are passed vertically through each other at the intersection points, so that honeycomb-shaped openings are formed between the wires. The total number of wires is preferably 8 to 128. The wires forming the mesh structure can be individual metal wires, but it is also possible to provide strands consisting of a plurality of small-diameter wires that are joined together to form a fine thread and are preferably twisted.

[0034] The term "opening" or "cell" refers to a lattice structure regardless of whether the opening is separated from the environment by a diaphragm, that is, an opening covered by a diaphragm or also called an opening. If necessary, the diaphragm can be applied outside or inside the grid structure. It is also possible to embed a lattice structure within the diaphragm. The diaphragm can be made of a polymer material such as polytetrafluoroethylene, polyester, polyamide, polyurethane, polyolefin, or polysulfone. Polycarbonate urethane (PCU) is particularly preferred.

[0035] One advantage of a stent structure made of interconnected bars or sutures, specifically manufactured by laser cutting, over a mesh structure made of wire is that a stent structure made of sutures is more resistant to shrinkage in length upon inflation. In the context of use as a thrombus removal device (a device for removing thrombi and blood clots from blood vessels), a stent structure made of interconnected sutures is also advantageous in that the radial force applied by such a stent structure is higher than the force applied by a mesh structure made of wire, even when the other comparative structures, suture Z-wire density, and suture Z-wire thickness are equivalent. This is because the sutures have connections fixed at the crossing points, while the wires of the mesh structure typically only pass through each other vertically.

[0036] The suture or wire can have a cross-sectional shape that is circular, elliptical, square, rectangular, or trapezoidal. In the case of a square, rectangular, or trapezoidal cross-sectional shape, it is advantageous to round the edges. Furthermore, it is reasonable to electropolish the stent structure to make it smoother, more rounded, and less traumatic. Furthermore, the risk of bacteria and other impurities adhering is also reduced. It is also possible to use flat sutures / wires in the form of thin strips, particularly metal strips.

[0037] The diameter of the stent structure in the freely expandable state is typically in the range of 2 to 8 mm, preferably in the range of 4 to 6 mm. The total length of the stent structure in the expanded state is typically 5 to 50 mm, preferably 10 to 45 mm, more preferably 20 to 40 mm.

[0038] For example, in the case of a stent structure made of sutures, this can be cut out from a tube with a wall thickness of 25 to 70 μm. Also, in the case of a mesh structure made of wires woven together, the wire thickness is preferably 20 to 70 μm. A microcatheter capable of delivering the device to the target position in the compressed state has, for example, an inner diameter of 0.4 to 0.9 mm.

[0039] Advantageously, the stent structure has a tapered proximal portion adjacent to the main cylindrical portion, and the proximal portion tapers towards the connection position with a guide wire or tube located around the stent structure. Thus, the guide wire can pass straight through the longitudinal direction of the device, i.e., can pass along the periphery of the stent structure. In this context, the periphery of the stent structure refers to the circumferential surface of the stent structure and can also be referred to as the side surface. The unique arrangement of the guide wire is also advantageous in that it prevents interference with the function of the intravascular device and the stent structure and prevents obstruction of blood flow. The unique arrangement of the guide wire also facilitates pulling the device out into a microcatheter or aspirating catheter if necessary.

[0040] It is advantageous for the distal portion of the guide wire to have as uniform a curvature as possible in the lateral or proximal direction. This facilitates tracking narrow and highly curved blood vessels using the guide wire. The distal end of the guide wire thus does not simply taper in the distal direction, but has a rounded shape, such as a J-shape. The curvature of the distal end of the guide wire is particularly important when there is little or no freedom of movement between the guide wire and the stent structure, i.e., when there is a fixed connection between the guide wire and the stent structure.

[0041] Furthermore, it is advantageous for the guide wire to have a certain degree of flexibility, especially at its distal end. This can be ensured by the selection of an appropriate material. For example, a shape memory metal with superelastic properties, such as a nickel-titanium alloy, can be used as the material for the guide wire. One such alloy is known as Nitinol. Other materials preferred as guide wires 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 such as a shape memory metal, while the more proximal region can be made of a different material such as stainless steel.

[0042] Furthermore, it is advantageous to visualize at least a portion of the distal portion of the guide wire by X-rays. This enables the treating physician to track, in the X-ray image, the advancement of the guide wire and thus the advancement of the stent structure and the microcatheter. For example, a portion of the guide wire may have platinum, or platinum-iridium markings, or a gold coating.

[0043] Assuming that the stent structure is automatically in an expanded configuration after release from the microcatheter, it is advantageous for the stent structure to be self-expanding. To ensure this, the stent structure can be composed, in particular, of a material that has shape memory properties or at least such properties. Nickel-titanium alloys (e.g., nitinol) are also suitable here. However, polymers with shape memory properties or other alloys such as nickel-titanium-chromium or nickel-titanium-copper alloys are also conceivable. The use of cobalt-chromium or cobalt-chromium-nickel alloys is also possible.

[0044] The cylindrical main portion is typically composed of a plurality of cells distributed on its outer periphery and is radially open. In other words, the main cylindrical portion, and in many cases the entire stent structure, has a grid or mesh structure composed of suture threads or wires, and the cells are arranged between the suture threads or wires.

[0045] The cells obtained within the stent structure are closed over the entire circumference, i.e., surrounded by suture threads or wires without interruption (so-called "closed cell design"). An "open cell design" is also possible, where at least some of the suture threads / wires have interruptions, so that the cells formed by the suture threads / wires are at least partially open and not completely closed. Such an open cell design has advantageous flexibility for highly curved blood vessels. On the other hand, in the open cell design, the pullability of the device is limited.

[0046] It is also possible to provide slots in the stent structure or the cylindrical main part, and these slots extend spirally on the side surface of at least a part of the stent structure, or longitudinally, that is, substantially parallel to the longitudinal axis, along the side surface of at least a part of the stent structure. Individual sutures or wires can reach into the slots to affect the radial force curve. A corresponding thrombus removal device having continuous slots parallel to the longitudinal axis is disclosed in International Publication No. WO 2009 / 105710 A1, and a device having a helical slot and a clamp bracket at the proximal end of the stent structure is disclosed in International Publication No. WO 2012 / 156069 A1.

[0047] To facilitate visualization of the insertion process by the treating physician, it is reasonable to provide X-ray visible markings in at least a portion of the intravascular device. The X-ray visible markings can be made of platinum, palladium, platinum-iridium, tantalum, gold, tungsten, or other X-ray visible metals. For example, X-ray visible / X-ray blocking coils can be attached at different points of the device. It is also possible to provide a coating of an X-ray visible material, such as a gold coating, on the stent structure, particularly on the sutures or wires of the stent structure. This can have a thickness of, for example, 1 to 6 μm. The coating with the X-ray visible material does not need to cover the entire stent structure, and it is particularly important to apply it to the area of the stent structure that expands towards the inner wall of the container, that is, substantially the main cylindrical section of the stent structure, in order to be able to observe the expansion of the stent structure. However, even if an X-ray visible coating is provided, it may be useful to additionally apply one or more X-ray visible markings to the device, particularly at the distal end of the stent structure.

[0048] An additional option is to use sutures or wires made of a metal having shape memory properties, in particular corresponding nickel-titanium alloys. These, in any case, have a core that is partially platinum. Such sutures / wires are known as DFT wires (DFT = drawn filled tubing). In this way, on the one hand, the advantageous properties of nickel-titanium, namely shape memory properties, and on the other hand, the advantageous properties of platinum, namely X-ray visibility, are combined.

[0049] At the proximal and distal ends of the stent structure, there may be ends of loose sutures or wires, but these should preferably be non-traumatic in order to avoid damage to the blood vessel. For example, by rounding, a non-traumatic design of the ends can be achieved. Another option is to form the sutures or wires into loops at one or both ends of the stent structure and return them to the stent structure. Thus, there are no longer free ends of sutures or wires at the ends of the stent structure, and the risk of damage to the blood vessel wall is reduced.

[0050] In particular, the intravascular device according to the invention can be a device for removing thrombi from a blood vessel. Such a device is placed within a microcatheter at the site of the thrombus to be removed, released from the microcatheter, and then the stent structure of the device is deployed within the thrombus to absorb the thrombus. Subsequently, the intravascular device is typically withdrawn together with the thrombus captured in an aspiration catheter having an inner diameter larger than that of the microcatheter, thereby preventing the thrombus, or a part of the thrombus, from being "squeezed out" when the stent structure is compressed. At the same time, fragments of the detached thrombus can be aspirated.

[0051] The present invention is particularly suitable for thrombus removal devices because the removal of thrombi that can cause ischemic stroke is time-critical. By omitting several consecutive steps while alternately using a guide wire, a microcatheter, and a thrombus removal device, that is, by inserting the microcatheter and the thrombus removal device into the blood vessel simultaneously with the guide wire, valuable time can be saved according to the present invention. Therefore, recanalization can be made possible more rapidly. Since the guide wire passes along the periphery of the stent structure, it does not substantially affect the effect of the thrombus removal device at the site. Once the thrombus is captured, the entire thrombus removal device including the guide wire is removed from the vascular system, and thus, usually, there is no need to separate the guide wire from the thrombus removal device.

[0052] However, the intravascular device according to the present invention can also be an implant, specifically, a stent for maintaining the blood vessel in an open state, a flow diverter for suppressing blood flow into an aneurysm, or a stent intended to prevent leakage of occluding substances from an aneurysm. Another possible use is as a treatment device for vasospasm, and this treatment can be based, in particular, on temporary or permanent expansion of the stent structure (see, for example, International Publication No. 2017 / 207689A1), or on the application of electrical, high-frequency, or ultrasonic pulses (see, for example, International Publication No. 2018 / 046592A1).

[0053] Particularly in the case of implants, it is necessary to be able to separate the stent structure and leave it in the blood vessel. While the guide wire / tube can be withdrawn from the vascular system, it is desirable to provide the possibility of separating the stent structure from the guide wire or tube of the stent structure so that the stent structure remains in the target position. In this way, the effect of the guide wire that affects the function of the stent structure is excluded. Therefore, the connection position between the guide wire / tube and the stent structure should be separable, and various separation mechanisms are known by the prior art. In particular, electrolytic, mechanical, thermal, and chemical separation options are known. In the case of intravascular devices that are originally intended to be removed from the vascular system, particularly thrombus removal devices and vasospasm treatment devices, separability can also be useful when the withdrawal of the device during treatment becomes a problem and the physician decides to leave the device in the blood vessel.

[0054] The separation location(s) for separating the stent structure is preferably an electrolytically corrodible detachment location. In this case, at least partial dissolution of the separation location is achieved by applying a voltage to the separation location using a voltage source. In electrolytic separation, the separation location is electrolytically corroded by applying a voltage so that the stent structure is separated from the guide wire. This is usually direct current and a low current (<3 mA) is sufficient. The separation location is usually made of metal and forms an anode when a voltage is applied, where oxidation, and thus dissolution of the metal, occurs.

[0055] To avoid anodic oxidation of the stent structure, it can be electrically insulated from the separation location and the guide wire. In the prior art, for example, with respect to occlusion coils for occluding aneurysms, electrolytic separation of implants is well known (see International Publication No. 2011 / 147567A1). This principle is based on the fact that when a voltage is applied, a separation location made of a suitable material, specifically a metal, usually undergoes at least such extensive dissolution by anodic oxidation, so that a region of the device located away from the corresponding separation location is released. The separation location can be made of, for example, stainless steel, magnesium, magnesium alloy, or cobalt-chromium alloy. A particularly preferred magnesium alloy is Resoloy® developed by MeKo in Sulzstedt, Germany (see International Publication No. 2013 / 024125A1). This is an alloy of magnesium and lanthanoids, particularly dysprosium. Another advantage of using magnesium and magnesium alloys is that it is physiologically unproblematic for residues of magnesium to remain in the body.

[0056] For example, while the separation location functions as an anode, the cathode can be positioned on the body surface. Also, another region of the device can form the cathode. Of course, the separation location must be connected in a manner that is electrically conductive to the voltage source. The guide wire itself can function as a conductor. When the cathode is disposed on the body surface, the resulting corrosion current is controlled by the surface of the cathode, so the surface area of the cathode needs to be significantly larger than the surface area of the anode. To some extent, the rate of the separation location can be controlled by adjusting the cathode surface relative to the anode surface. Thus, the device according to the present invention can also include a voltage source and, optionally, an electrode that can be disposed on the body surface.

[0057] As an alternative to the electrolytically dissolved separation position, other separation positions known in the prior art can also be used. In particular, separation positions that can be separated mechanically, thermally, or chemically can be used. In the case of mechanical separation, typically there is a form, force, or frictional connection that is released when the stent structure is released, whereby the stent structure separates from the guide wire or tube. In the case of a thermal separation position, the connection can be severed by heating the separation position, at which time the separation position softens or melts to the degree of separation. Finally, chemical separation is also possible, which is carried out by a chemical reaction at the separation position.

[0058] Different types of separation, such as electrolytic separation and mechanical separation, can also be combined with each other. The mechanical connection is specifically established between units via a positive fit, and the fixed position is maintained until the element maintaining the mechanical connection is electrolytically corroded.

[0059] At least a part of the stent structure can have a coating that prevents the accumulation of platelet aggregation. This antithrombotic coating has a functional layer, and the functional layer can be formed by oligo- or polymerization of at least one sugar alcohol and / or monosaccharides functionalized with polymerizable groups. Such an antithrombotic coating is disclosed in International Publication No. WO 2018 / 210989 A1.

[0060] The device according to the present invention can be used particularly in the neurovascular region, but it is also possible to use it in the cardiovascular or peripheral regions.

[0061] In addition to the intravascular device, the present invention also relates to a method for introducing an intravascular device according to the present invention into a blood vessel. The device is introduced into a microcatheter, and the distal end of the guide wire is arranged to protrude distally from the microcatheter. The microcatheter is advanced distally within the blood vessel together with the intravascular device disposed within the microcatheter. Before advancing the intravascular device to the target position together with the microcatheter, a guide catheter having a relatively large lumen is often used first, through which a microcatheter having a small lumen is further advanced distally. In neurovascular applications, for example, the guide catheter is used to advance from the femoral artery to the carotid artery, and then only the microcatheter is used for further advancement.

[0062] Furthermore, the present invention also relates to a combination of an intravascular device and a microcatheter, wherein the intravascular device is disposed within the microcatheter, and the distal end of the guide wire protrudes distally from the microcatheter.

[0063] Finally, the present invention also relates to the use of the device according to the present invention for removing thrombus from a blood vessel, or a corresponding method.

[0064] The description of all features of the invention relates to all embodiments in each case, in particular, to both a first embodiment in which a stent structure is connected to a guide wire via a connection position and an alternative embodiment having a connection position to a tube, unless otherwise apparent from the context.

[0065] With reference to the examples of the embodiments shown in the figures, the invention will be described in more detail. It should be noted that the figures show variations of the preferred embodiments of the invention, but the invention is not limited thereto. Generally, the invention includes any combination of the technical features listed in the claims or the technically related elements described in the description within the technically useful scope.

Brief Description of the Drawings

[0066]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0067] FIG. 1 shows a side view of a device according to the first embodiment of the present invention. The intravascular device 1 is used to capture thrombus and consists essentially of a stent structure 2 and a guide wire 5. The stent structure 2 is shown here in an expanded state, and the guide wire 5 passes along the side of the stent structure 2. The guide wire 5 and the stent structure 2 are connected to each other via a connection position 6, which in this embodiment is a fixed connection.

[0068] The stent structure 2 has a cylindrical main portion 3 and a proximal portion 4 that tapers towards the periphery of the stent structure 2. The suture of the stent structure 2 terminates at the connection position 6 with the guide wire 5. The suture of the stent structure 2 forms a plurality of cells 7 distributed over the circumferential surface of the stent structure, which are radially open so as to be able to penetrate thrombus upon expansion. The guide wire 5 projects sufficiently distally from the stent structure 2 to perform its function of guiding the device 1 through the vascular system. The distal portion 8 of the guide wire 5 is J-shaped to facilitate probing and minimize the risk of damage to the blood vessel. To visualize the insertion and release process, the stent structure 2 is provided with a radiopaque marking 9 at its distal end.

[0069] Figure 2 shows a second embodiment of the present invention. In contrast to the first embodiment, here the connection position 6 is designed as a fixed bearing, and the guide wire 5 is rotatable relative to the stent structure 2. Thereby, further, the introduction of the intravascular device 1 into the vascular system is simplified. Here too, the guide wire 5 projects significantly more distally than the stent structure 2 and has a distally curved lateral portion 8.

[0070] Finally, Figure 3 shows a third embodiment of the invention. Here, the connection position 6 is designed as a floating bearing, and the guide wire 5 is not only rotatable relative to the stent structure 2 but also has a limited displacement in the longitudinal direction. The longitudinal displacement is indicated by arrow 11 and is limited by two stops 10. This additional degree of freedom gives the treating physician additional options when inserting and advancing the intravascular device 1 into the vascular system.

[0071] Figure 4 shows an alternative embodiment of the present invention, in which the stent structure 2 is not connected to the guide wire 5 via the connection position 6 but is connected to a tube 12, and the guide wire 5 extends through the interior of the tube 12 and extends distally beyond the stent structure. The guide wire 5 is rotatable within the tube 12 and can move longitudinally. Also in this embodiment, the intravascular device 1 is arranged in a microcatheter not shown here, and the guide wire 5 projects distally from the microcatheter, enabling the guide wire 5 to advance through the blood vessel and probe.

Claims

1. An intravascular device having a stent structure (2), wherein the stent structure (2) exists in an expanded state that is at least temporarily released within a blood vessel and a compressed state that is introduced into the blood vessel within a microcatheter, and the stent structure (2) has a substantially cylindrical main portion (3), the stent structure (2) has at least one connection position (6) with a guide wire (5), the guide wire (5) extends distally from the stent structure (2), and the guide wire (5) passes along the circumference of the stent structure (2), characterized in that it is an intravascular device.

2. The connection position (6) between the stent structure (2) and the guide wire (5) is a fixed bearing, and the guide wire (5) is rotatable with respect to the stent structure (2), characterized in that it is the intravascular device according to claim 1.

3. The connection position (6) between the stent structure (2) and the guide wire (5) is a floating bearing, and the guide wire (5) is displaced longitudinally and the guide wire (5) is rotatable with respect to the stent structure (2), characterized in that it is the intravascular device according to claim 1.

4. The longitudinal mobility of the guide wire (5) proximally and distally is limited by a stop portion (10), characterized in that it is the intravascular device according to claim 3.

5. The stent structure (2) has at least two connection positions (6) with the guide wire (5), one connection position (6) is a fixed bearing, the guide wire (5) is rotatable with respect to the stent structure (2), one connection position (6) is a floating bearing, the guide wire (5) is displaced longitudinally and the guide wire (5) is rotatable with respect to the stent structure (2), and the fixed bearing and the floating bearing are spaced apart from each other in the longitudinal direction, characterized in that it is the intravascular device according to any one of claims 1 to 4.

6. An intravascular device having a stent structure (2), wherein the stent structure (2) exists in an expanded state that is at least temporarily released within a blood vessel and a compressed state that is introduced into the blood vessel within a microcatheter, and the stent structure (2) has a substantially cylindrical main portion (3), The intravascular device is characterized in that the stent structure (2) has at least one connection position (6) with the tube (12), the guide wire (5) passes through the tube (12), and can be carried to a position extending more distally than the stent structure (2).

7. The intravascular device according to claim 6, characterized in that the guide wire (5) passes 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 slots or notches extending substantially orthogonally or obliquely with respect to its longitudinal direction, thereby increasing 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) adjacent to the cylindrical main portion (3), and the proximal portion (4) tapers towards the connection position (6) with the guide wire (5) or the tube (12) located around 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) bent in the lateral or proximal direction.

12. The intravascular device according to any one of claims 1 to 11, characterized in that at least a part of the distal portion (8) of the guide wire (5) is designed to be visible by X-ray.

13. The intravascular device according to any one of claims 1 to 12, characterized in that the stent structure (2) is self-expandable and is designed on the premise that it will independently expand 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 thrombus from blood vessels.

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 position (6) between the stent structure (2) and the guide wire (5) or the tube (12) is designed to be separable electrolytically, mechanically, thermally, or chemically.

17. The combination of the intravascular device (1) and the microcatheter according to any one of claims 1 to 16, wherein the intravascular device (1) is disposed within the microcatheter such that the distal end of the guide wire (5) projects distally from the microcatheter.

18. A method of introducing the intravascular device (1) according to any one of claims 1 to 16 into a blood vessel, comprising introducing the intravascular device (1) into a microcatheter, disposing the distal end of the guide wire (5) to project distally from the microcatheter, and advancing the microcatheter distally into the blood vessel together with the intravascular device (1) located within the microcatheter.

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