Devices and methods for neuroendovascular intervention - Patents.com

Abstract

In particular, a device for intraluminal neurovascular intervention for the treatment of ischemic stroke is provided. The device comprises a catheter (2) for insertion into a patient's circulatory system (CS) for aspirating one or more blood clots (C) present within the circulatory system (CS). The distal outer section (22) of the catheter (2) has an unexpanded state for facilitating passage of the catheter through the circulatory system, wherein the diameter (D2) of the distal outer section (22) is smaller than the diameter (D1) of the proximal outer section (21) of the catheter (2), and a radially expanded state for facilitating aspiration of one or more blood clots (C) through the catheter (2). Additionally, a method for applying such a device is provided.

Description

[Technical field]

[0001] The present invention relates to devices and methods for neuroendoluminal intervention, particularly for the treatment of ischemic stroke. The devices may be referred to as clot retrieval devices, particularly for the removal of a blood clot from a blood vessel, and the methods may be referred to as methods for the retrieval of a blood clot from a blood vessel. [Background technology]

[0002] Ischemic stroke is caused by a partial or complete interruption to cerebral blood perfusion. Such interruption can be caused by a thrombus or an embolus, i.e., a blood clot originating from a more proximal location in the bloodstream that becomes trapped in a narrowing intracranial vessel. Interruption of blood flow to a portion of the brain for any extended period of time results in an area of ​​infarcted tissue, known as a core infarct, that is irreversibly damaged and grows larger over time. The infarcted area of ​​the brain will result in neurological deficits that can range from mild speech and coordination problems to a total loss of muscle and cognitive control.

[0003] The oxygen-deprived area surrounding the core infarct also grows larger and the disruption lasts longer. This area, known as the penumbra, can regenerate if blood perfusion is restored in a timely manner. This phenomenon of treatable ischemic events has given rise to the phrase "time is brain," now common among associated clinicians.

[0004] In recent years, techniques for mechanical removal of such emboli have allowed for reperfusion of blood flow and effective treatment of stroke in some cases. During the past few years, the first of several clinical studies were published that demonstrated the effectiveness of stent retrievers for restoring blood flow versus the standard of care at the time, which was intravenous thrombolytic agents and aspiration clot retrieval.

[0005] Mechanical clot retrieval devices are, for example, metal baskets or stents connected to a retrieval wire. During a clot removal procedure, a guidewire is placed across the length of the clot and a catheter is passed over the guidewire to cross the clot. The clot retrieval device is delivered to the required location through the catheter. The catheter or sheath is retracted from over the clot retrieval device, which then expands and engages the clot. The clot retrieval device and the clot integrated therein can then be removed through the vessel using tension by withdrawing the retrieval wire. Optionally, a suction catheter can be used to assist in the removal.

[0006] In many cases, the clot cannot be removed intact during the first pass of the clot retrieval device, and multiple passes are required to restore blood flow. Improving clot removal on the first pass is the target of many current developments in the art.

[0007] In practice, clinicians will use a number of different tools to remove clots during endovascular procedures. Generally, a guidewire will be placed into the femoral artery using a modified Seldinger technique and threaded through the carotid artery and into the cerebral vasculature of the brain.

[0008] The guidewire is then pushed through the clot. Once the guidewire is in place, a very narrow tubular catheter known as a microcatheter (approximately 0.4 mm diameter) is advanced over the wire to the distal side of the clot.

[0009] The guidewire is then removed and a stent retriever is pushed through the microcatheter and deployed along the length of the clot. The stent retriever engages the clot and is then retracted to remove the clot from the patient's circulatory system. In most cases, as the procedure is performed, suction is simultaneously applied through a larger diameter catheter that is passed over the microcatheter in close proximity to the clot. The aspiration catheter is stiffer than the microcatheter due to its larger diameter and the reinforcement required to prevent collapse during aspiration. The microcatheter is therefore also required as a support and guide for the introduction of the aspiration catheter through the vasculature.

[0010] The same applicant's yet unpublished European Patent Application No. EP 19 167 604.8 discloses a catheter device for the removal of blood clots from the circulatory system of a human or animal patient in which multiple clot engaging elements can be deployed independently of each other. In this way, the rate of first pass clot removal can be improved.

[0011] In addition to the techniques mentioned above, there are several different approaches described using a combination of a stent retriever and an aspiration catheter. Some of these techniques describe complete withdrawal of the stent retriever and clot into the aspiration catheter. Other approaches are directed to withdrawal of the clot and stent retriever with an aspiration catheter, where the proximal portion of the clot is attached to the aspiration catheter during removal.

[0012] The clot retrieval approach chosen is often influenced by the clot composition; in some cases, such as when the clot is a very soft thrombus, an aspiration catheter alone is sufficient to remove the entire clot via suction. In this case, a microcatheter is still required to assist in aiding in navigation of the aspiration catheter to the desired site.

[0013] Regardless of the specific technique used, removal of the clot without delay is crucial. Guidewires and microcatheters are generally advanced quickly to the clot, but positioning of the aspiration catheter can be a limiting factor. The process of advancing the aspiration catheter becomes difficult, especially after passing through the internal carotid artery. This is due to the narrow and tortuous vessels from this point onwards in the cerebral vasculature, and is exacerbated in older patients with diseased and elongated vasculature. This time-consuming part of the procedure can affect the patient's clinical outcome. In cases where the clot is not removed during the first pass, the cumulative time taken between multiple attempts can be significant.

[0014] It is known to arrange devices with distally expanding funnels at the distal end of the aspiration catheter. These devices are generally separate from the aspiration catheter, attached through the lumen, and pushed out and expanded from the distal end of the aspiration catheter. Such devices are intended to widen the already large lumen diameter of the aspiration catheter, entangle the stent retriever for removal and / or the clot, and ensure that no microemboli are released during clot removal. WO 02 / 087677 A2, US 2017 / 0303949 A1, WO 2016 / 113047 A1, US 2019 / 0269491 A1, US 2017 / 0333060 A1 are examples of documents directed to this type of technique.

[0015] WO 2017 / 097616 A1 discloses several devices and methods for removing emboli from blood vessels. According to a first embodiment shown in Figures 1-2f herein, a stent retriever is first deployed with a microcatheter. To improve the clot removal process, an aspiration catheter is then advanced to the location of the clot.

[0016] Using an aspiration catheter, a clot acceptor device is deployed that seals circumferentially against the distal section of the aspiration catheter so that the stent retriever and clot can be aspirated through the tapered opening of the acceptor device during the removal process. In another embodiment shown in Figures 10-11d of the same document, the stent retriever is also deployed using a microcatheter. The aspiration catheter is then advanced to the location of the clot to aspirate the stent retriever and clot. It is proposed that the distal tip of the aspiration catheter is expandable to form a tapered opening to facilitate acceptance of the clot during the aspiration and removal process.

[0017] US 8,425,549 B2 discloses a catheter having a distal portion that can be radially expanded with a coil or helical ribbon that is distally displaceable within the catheter. The expanded configuration allows for the application of negative pressure through the lumen of the catheter to aspirate occlusive material through the distal end opening of the catheter and into the lumen.

[0018] Further devices for intraluminal neurovascular intervention of the type shown are disclosed in WO 2016 / 126974 A1, WO 2018 / 169959 A1, and WO 98 / 23320 A1.

[0019] Besides the catheter devices described above, introducer sheaths are also known, which are short cannula-like devices used for vascular access. They are percutaneously introduced into the target vessel and a central dilator is then removed, allowing access for the insertion of guidewires and other devices such as catheters. In recent years, several introducer devices have been developed that have the ability to expand and accommodate devices larger than the nominal vessel size. Examples of expanding sheath type devices are the Edwards eSheath® and the Terumo Solopath®. Summary of the Invention [Means for solving the problem]

[0020] It is an object of the present invention to provide a device for intraluminal neurovascular intervention, particularly for the treatment of ischemic stroke, that allows for an overall easier and more rapid removal of blood clots from blood vessels.

[0021] This object is solved by a device as claimed in claim 1. Further embodiments of the device are provided in dependent claims 2-15. A method for intraluminal neurovascular intervention, which may in particular be used in combination with a device as claimed in claim 1, is provided in claim 16.

[0022] The present invention relates to a device for intraluminal neurovascular intervention, in particular for the treatment of ischemic stroke, and more particularly for the removal of blood clots from the circulatory system of a human or animal patient, comprising: a catheter for insertion along a longitudinal length thereof into a circulatory system of a human or animal patient, the catheter having a proximal outer section with a first diameter and a distal outer section with a second diameter; The catheter provides a device that is adapted to aspirate one or several blood clots present within the circulatory system.

[0023] The distal outer section of the catheter has an unexpanded state in which the second diameter is smaller than the first diameter to facilitate passage of the catheter through the circulatory system, and further has a radially expanded state to facilitate aspiration of one or more blood clots through the catheter.

[0024] Thus, in the present device as shown, a microcatheter and an aspiration catheter are combined into one catheter. The catheter has two states or configurations, one being a first configuration whereby the catheter has a relatively wide proximal outer section that is generally wide enough to function as an aspiration catheter, and a narrow distal outer section that functions as a microcatheter. In this first configuration, the distal outer section is adapted to be easily passed through the vasculature. The catheter can then preferably be reversibly changed to a second state or configuration whereby the distal outer section is expanded to a wider diameter, preferably approximately equal to the diameter of the proximal outer section. This approach allows the catheter to be easily and quickly passed to the target site and subsequently expanded to facilitate removal of one or several clots by aspiration. Using this design, clinicians do not waste valuable time passing a large aspiration catheter through tortuous vessels. In addition, the combination of a microcatheter and an aspiration catheter into a single catheter may also represent a cost savings.

[0025] The catheter is preferably adapted to be inserted into the femoral artery of a normal adult human patient and passed to the brain, in particular the middle cerebral artery of the patient. The length of the catheter is therefore preferably such that the catheter can extend at least from the femoral artery of a normal adult human patient to the brain, in particular the middle cerebral artery of the same patient. Depending on the application (e.g., whether in animals or humans, in children, in female or male adults, etc.), the catheter preferably has a total length of at least 30 cm, more preferably at least 40 cm. For use in humans, in particular adult humans, the total length of the catheter is preferably within the range of 100 cm to 200 cm, more preferably within the range of 130 cm to 180 cm.

[0026] Along its longitudinal extension, the catheter preferably has a proximal outer section and a distal outer section arranged directly behind each other along the longitudinal direction of the catheter, in particular merging directly into each other via a transition. The proximal outer section defines a first diameter, preferably the outer diameter of the catheter, and the distal outer section defines a second diameter, preferably also the outer diameter of the catheter. The second diameter of the distal outer section changes length depending on when the distal outer section is brought from its unexpanded state to its expanded state (or vice versa).

[0027] In the expanded state, the second diameter of the distal outer segment is preferably enlarged as compared to the unexpanded state. From the unexpanded state to the expanded state of the distal outer segment, the second diameter preferably increases by a factor of at least 1.5, more preferably by a factor of at least 2, and most preferably by a factor of at least 3. The first diameter of the proximal outer segment preferably remains unchanged when the distal outer segment is brought from its unexpanded state to its expanded state.

[0028] In absolute terms, the second diameter of the distal outer segment in the unexpanded state is preferably within the range of 0.1 to 1 mm, more preferably 0.1 to 0.8 mm, even more preferably 0.2 to 0.6 mm, most preferably 0.3 to 0.5 mm, in particular approximately 0.4 mm. In the expanded state, the second diameter of the distal outer segment is preferably within the range of 1 to 2 mm, more preferably 1.2 to 1.8 mm, most preferably 1.4 to 1.6 mm, in particular approximately 1.5 mm.

[0029] In an unexpanded state, the second diameter of the distal outer segment is preferably at least 30% smaller, more preferably at least 50%, and most preferably at least 70% smaller than the first diameter of the proximal outer segment.

[0030] Preferably, the catheter is designed such that the second diameter of the distal outer segment cannot be expanded beyond the first diameter of the proximal outer segment.

[0031] The term "blood clot" refers to an obstruction in a blood vessel of the circulatory system of a human or animal patient that needs to be removed to allow free blood flow in an individual blood vessel. The blood clot may be, for example, a thrombus or embolus originating from a more proximal location in the blood stream, such as from the heart or lungs, becoming trapped in a narrow intracranial vessel, i.e., in the neurovasculature of the patient.

[0032] In a particularly preferred embodiment, the device additionally comprises a clot retriever adapted to be positioned in the circulatory system with the catheter and retracted into the expanded distal outer section of the catheter to engage one or several clots present in the circulatory system. The device is preferably adapted to aspirate one or several clots through the catheter while simultaneously retracting the clot retriever. In this way, clot removal is particularly reliable and safe.

[0033] The clot retriever may in particular have the form of a stent retriever. Advantageously, the clot retriever extends throughout the catheter and is connected to a retriever wire, which in particular serves to actuate the clot retriever for retracting it with one or several clots from the vasculature.

[0034] In certain embodiments, the clot retriever can include multiple clot engaging elements, which, when provided, can be adapted to be deployed independently of one another, such as in the device disclosed in the same applicant's yet unpublished European Patent Application No. EP 19 167 604.8, the entire disclosure of which is incorporated herein by reference.

[0035] The clot retriever preferably comprises a non-expanded state and a radially expanded state. In the non-expanded state, the clot retriever usually has an outer radial diameter that is preferably several times smaller than the outer radial diameter in the expanded state. The clot retriever is thus preferably adapted to radially expand upon deployment, which means that the radial expansion of the clot retriever increases. With the expansion, at least a part of the clot retriever engages with the clot, either directly or when being retracted. In the non-expanded state, the clot retriever can be inserted into a catheter to be positioned in the circulatory system, in particular to be brought to the area of ​​the clot with the catheter. Thus, in the non-expanded state, the clot retriever is preferably arranged in the catheter and held in place by the latter, such that the clot retriever moves with the catheter.

[0036] The clot retriever is preferably composed, at least in part, of an elastic metal, such as Nitinol, or another alloy, commonly used for stent production. The clot retriever preferably comprises one or more stent-like structures, which may be laser cut from Nitinol or another superelastic metal.

[0037] The clot retriever is preferably brought from its unexpanded state to its expanded state due to its elasticity. Thus, the clot retriever can advantageously be reversibly collapsed when required, for example, to be loaded into a catheter. In the unexpanded state, the clot retriever is preferably prestressed along the radial direction. Expansion is then preferably performed by moving the radially limiting element, i.e., the catheter, at least partially away from the clot retriever, which is thereby allowed to expand radially due to its elastic nature.

[0038] In the expanded state of the distal outer segment, the second diameter of the distal outer segment is preferably approximately the same as the first diameter of the proximal outer segment. In this manner, aspiration of the clot can be optimally performed through the proximal and distal outer segments. In some embodiments, the second diameter can be even larger than the first diameter in the expanded state of the distal outer segment, for example, to facilitate retraction of the clot retriever and / or clot into the catheter.

[0039] In a particularly preferred embodiment, the distal outer segment has a cylindrical shape in the unexpanded and / or expanded state. The cylindrical shape of the distal outer segment is advantageous not only for facilitating passage of the catheter through the vasculature, but also for holding the clot retriever securely along its entire longitudinal extension inside the distal outer segment during the positioning process. Advantageously, the distal outer segment has a cylindrical shape essentially along its entire longitudinal length. The entire longitudinal length of the distal outer segment is preferably greater than 1 cm, more preferably greater than 2 cm, and most preferably greater than 3 cm. In certain embodiments, the length of the distal outer segment can further be greater than 5 cm, greater than 10 cm, or greater than 15 cm. In a particularly preferred embodiment, the distal outer segment has a length in the range of 15 cm to 20 cm.

[0040] The distal outer section advantageously comprises at least one reinforcing element, in particular a braided or knitted or crocheted structure, adapted to radially expand when longitudinally compressed and / or radially contract when longitudinally stretched and / or radially expand when longitudinally stretched and / or radially contract when longitudinally compressed. The radial expansion or contraction in response to a change in the length of the reinforcing element is preferably reversible. Thus, the distal outer section of the catheter can be brought from a non-expanded state to an expanded state, in this case by means of at least one reinforcing element that compresses longitudinally (or that stretches longitudinally), and preferably vice versa. In other words, the at least one reinforcing element is adapted to convert, for example, a longitudinal movement of the actuating element into a radial expansion and / or a radial contraction of the distal outer section. In order to compress and / or stretch the at least one reinforcing element in the longitudinal direction, the actuating element is preferably attached or attachable to the distal outer section, in particular to the proximal or distal end of the at least one reinforcing element. The other of the distal or proximal end is preferably stationary relative to the proximal outer section. Advantageously, the actuating element is releasably attached or releasably attachable to the at least one reinforcing element, in particular to the proximal or distal end of the at least one reinforcing element. The releasable attachment allows the actuating element to be removed from the catheter, for example after expanding the distal outer section. The actuating element can be a push element or a pull element. The push element can be, for example, in the form of a push screw or a wire, a push tube or a push coil. The pull element can be, correspondingly, in the form of a pull screw or a wire, a pull tube or a pull coil.

[0041] In a particularly preferred embodiment, the actuating element has the form of a push tube, and the device additionally comprises a rear wire attached to the distal end of at least one reinforcing element and extending into the push tube. By moving the push tube longitudinally along the distal direction to the point where the rear wire is attached to at least one reinforcing element or even further away, the push tube can be locked to at least one reinforcing element via the rear wire, so that the at least one reinforcing element can be longitudinally stretched by the push tube. This embodiment has the particular advantage that the actuating element can be locked to and released from the reinforcing element as frequently as required. Of course, in an alternative embodiment, it would also be possible to attach the rear wire to the proximal end of at least one reinforcing element in order to longitudinally compress the at least one reinforcing element by means of a push tube locked to the rear wire.

[0042] The at least one reinforcing element, preferably in the form of a braided structure, advantageously also serves to prevent twisting of the catheter, in particular to prevent the catheter from collapsing during passage of the catheter through the vasculature and during aspiration of blood clots. The at least one reinforcing element may in particular form a structural support element for the distal outer section. The at least one reinforcing element serves in particular to prevent collapse of the distal outer section of the catheter during aspiration. According to a preferred embodiment, the at least one reinforcing element is covered.

[0043] The distal outer section is preferably adapted to be brought not only from its unexpanded state to its expanded state, but also from its expanded state to its unexpanded state. The change from the unexpanded state to the expanded state (and vice versa) can preferably be actively effected by a clinician using an actuation element.

[0044] In another embodiment, the catheter additionally comprises an inner tubular element, in particular an inner tube, which can be moved longitudinally relative to the distal outer section to bring the distal outer section from its unexpanded state to its expanded state. The inner tubular element thus advantageously serves as an actuation element for the clinician. The inner tubular element preferably defines the inner lumen of the catheter essentially along the entire length of the catheter. By advancing the inner tubular element to expand the distal outer section, a particularly smooth inner and outer transition between the proximal and distal outer sections can be achieved when the distal outer section is in its expanded state. The distal outer section can thus preferably be expanded by pushing the inner tubular element into the inner lumen of the distal outer section.

[0045] The distal outer section is preferably made of a resilient material that maintains the distal outer section in its unexpanded state when the inner tubular element is arranged coaxially and proximal to the distal outer section and is stretched radially outward when the inner tubular element is moved coaxially into the distal outer section. Due to its resilience, the distal outer section preferably automatically returns to its unexpanded state when the inner tubular element is again retracted from the distal outer section.

[0046] Alternatively, the distal outer section may comprise a braided structure and an outer shell structure, the braided structure being attached with a first end to the inner tubular element, in particular to the distal end of the inner tubular element, and with a second end to the distal end of the outer shell structure, the braided structure then being adapted to radially expand when longitudinally compressed, preferably by moving the inner tubular element towards the distal end of the outer shell structure.

[0047] The inner tubular element can comprise or be formed by a hypodermic tube or coil, which preferably extends along the entire longitudinal length of the inner tubular element. The windings of the coil are preferably placed immediately next to each other, so that there are no gaps between adjacent windings. The coil is therefore preferably tightly wound. The construction of the inner tubular element as a coil is advantageous with regard to the desired flexibility of the inner tubular element on the one hand and its resistance to twisting and crushing during suction on the other hand. The inner tubular element may be coated with a low-friction coating, such as PTFE or parylene. In another embodiment, the inner tubular element can also be in the form of a continuous wire-formed structure, which in each case extends in alternating circumferential direction over at least a portion of the circumference. In yet another embodiment, the inner tubular element can be in the form of a plurality of C- or O-shaped elements attached, in particular welded, to a longitudinally extending wire.

[0048] In the unexpanded state of the distal outer section, advantageously also in the expanded state, the transition of the catheter from the proximal to the distal outer section is preferably defined by a gradually decreasing outer and / or inner diameter that is continuous, i.e., without abrupt changes or discontinuities. Abrupt inner and / or outer edges that could cause vasculature damage during catheter passage or aerodynamic turbulence during aspiration can thus be avoided.

[0049] The device preferably comprises an actuating element by means of which the clinician can actively change the state of the distal outer section from a non-expanded state to an expanded state, and advantageously also vice versa. As already mentioned above, such an actuating element can be, for example, in the form of a pushing or pulling element, or in the form of an inner tube that is movable relative to the inner tubular element, in particular the distal outer section. However, the actuating element can also have a different form. In an embodiment, the actuating element can be attached to the proximal or distal end of the distal outer section, the distal outer section being adapted in this case to be brought from its non-expanded state to its expanded state upon actuation of the actuating element. For example, if the distal end is pulled in the proximal direction by a pulling element, the actuating element can be a pulling element, such as a pulling screw, and the distal outer section can be adapted to be brought from its non-expanded state to its expanded state. In this case, the distal outer section is preferably pressed by the pulling element towards the proximal outer section in order to be compressed in the longitudinal direction. Due to this longitudinal compression, the distal outer section is radially expanded, which can be caused, for example, by the braided structure of the distal outer section. In another embodiment, the actuating element can be a pushing element, such as a pushing screw, having a certain stiffness against bending, and the distal outer section can be adapted to be brought from its expanded state to its unexpanded state when the distal end is pushed in the distal direction by the pushing element. In this case, the distal end of the distal outer section is preferably pushed away from the proximal outer section by the pushing element, stretching the distal outer section, such as in the longitudinal direction. Due to this longitudinal stretching, the distal outer section is radially contracted, which can be caused, for example, by the braided structure of the distal outer section. In another embodiment, the actuating element can also be a tubular structure and can be reversibly attached to the distal end of the distal outer section. Reversible attachment can be achieved using means such as weak adhesive bonding, magnetic attachment, or friction caused by the compressive force of the elastic outer shell structure.

[0050] In another alternative embodiment, the actuation element can be a coiled thread adapted to expand radially within the region of the distal outer section when compressed longitudinally, the coiled thread preferably being made of a shape memory material, in particular a shape memory alloy such as Nitinol (NiTi).

[0051] Of course, the actuating elements described above, i.e., inner tubular element, pushing element, pulling element, and coiled screw, can also be combined to facilitate expansion of the distal outer section.

[0052] To facilitate passage of the catheter through the circulatory system and to prevent intraluminal damage, a lubricious coating is preferably provided on the outer surface of the catheter, particularly the outer surface of the distal outer section.

[0053] Furthermore, the present invention is directed to a method for intraluminal neurovascular intervention using a device comprising a catheter having a proximal outer section with a first diameter and a distal outer section with a second diameter, in particular using a device as described above, the method comprising at least: a.) inserting a catheter along its longitudinal length into the circulatory system of a human or animal patient; b.) aspirating one or several blood clots present in the circulatory system through the catheter; Includes.

[0054] The distal outer section of the catheter used in the method comprises an unexpanded state in which the second diameter is smaller than the first diameter, and a radially expanded state. During step a.), the distal outer section is in its unexpanded state to facilitate passage of the catheter through the circulatory system. During step b.), the distal outer section is in its expanded state.

[0055] The method steps a.) and b.) as described above are preferably carried out in the sequential order as shown, in particular one after the other.

[0056] Thus, after insertion of the catheter into the circulatory system, the distal outer section of the catheter is brought from its unexpanded state to its expanded state to facilitate aspiration of one or more blood clots through the catheter.

[0057] The distal outer section of the catheter used in the method preferably comprises a non-expanded state in which the second diameter is smaller than the first diameter and a radially expanded state in which the second diameter may in particular be the same as the first diameter. In this case, the catheter is preferably inserted in step a.) with the distal outer section in its non-expanded state to facilitate passage of the catheter through the circulatory system. In step b.), one or several blood clots are preferably aspirated with the distal outer section in its expanded state. Furthermore, the distal outer section of the catheter used in the method advantageously comprises at least one reinforcing element, in particular a braided structure, adapted to radially expand when longitudinally compressed and / or radially contract when longitudinally stretched.

[0058] The apparatus preferably also comprises a clot retriever which is positioned, i.e. deployed, in the circulatory system by means of the catheter in a further method step between steps a.) and b.) in order to engage the clot retriever with one or several clots present in the circulatory system. During aspiration in step b.), the clot retriever is preferably simultaneously retracted into the catheter. The present invention provides, for example, the following: (Item 1) 1. A device for intraluminal neurovascular intervention, in particular for the treatment of ischemic stroke, comprising: A catheter (2) for insertion along its longitudinal length into the circulatory system (CS) of a human or animal patient, said catheter (2) having a proximal outer section (21) with a first diameter (D1) and a distal outer section (22) with a second diameter (D2). Equipped with The catheter (2) is adapted to aspirate one or several blood clots (C) present in the circulatory system (CS), the distal outer section (22) of the catheter (2) having a non-expanded state for facilitating passage of the catheter (2) through the circulatory system (CS) in which the second diameter (D2) is smaller than the first diameter (D1), and a radially expanded state for facilitating aspiration of the one or more blood clots (C) through the catheter (2); An apparatus comprising: (Item 2) Additionally, the device described in item 1 further comprises a clot retriever (4) adapted to be positioned within the circulatory system (CS) with the catheter (2) and to be retracted into the expanded distal outer section of the catheter (2) to engage the one or more clots (C) present within the circulatory system (CS). (Item 3) 3. The device according to item 1 or 2, wherein in the expanded state, the second diameter (D2) of the distal outer section (22) is the same as or greater than the first diameter (D1) of the proximal outer section (21). (Item 4) 2. The device of claim 1, wherein the distal outer section (22) has an essentially cylindrical shape along its entire longitudinal length in the unexpanded state, and preferably also in the expanded state. (Item 5) 2. The device of claim 1, wherein the distal outer section (22) comprises at least one reinforcing element (222), in particular a braided structure adapted to radially expand when longitudinally compressed, or radially contract when longitudinally stretched, or radially expand when longitudinally stretched, or radially contract when longitudinally compressed. (Item 6) 2. The device of any one of the preceding claims, wherein the distal outer section (22) is adapted to be brought from its unexpanded state to its expanded state and from its expanded state to its unexpanded state. (Item 7) The device according to any one of the preceding items, wherein the catheter (2) additionally comprises an inner tubular element (23), in particular an inner tube, which can be moved longitudinally relative to the distal outer section (22) to bring the distal outer section (22) from its unexpanded state to its expanded state. (Item 8) 8. The device of claim 7, wherein the distal outer section (22) is made of an elastic material that maintains the distal outer section (22) in its unexpanded state when the inner tubular element (23) is arranged outside the distal outer section (22) and that stretches radially outward when the inner tubular element (23) is moved into the distal outer section (22). (Item 9) 8. The device of claim 7, wherein the distal outer section (22) comprises a braided structure (222) and an outer shell structure (223), the braided structure (222) being attached to the inner tubular element (23) with a first end and to a distal end of the outer shell structure (223) with a second end, and the braided structure (222) is adapted to radially expand when longitudinally compressed by moving the inner tubular element (23) toward the distal end of the outer shell structure (223). (Item 10) 10. The device according to any one of claims 7-9, wherein the inner tubular element (23) preferably comprises a coil (231) extending along the entire longitudinal length of the inner tubular element (23). (Item 11) 2. The device of claim 1, wherein in an unexpanded state of the distal outer section (22), the transition of the catheter (2) from the proximal outer section (21) to the distal outer section (22) is defined by a continuously decreasing outer and / or inner diameter. (Item 12) 2. The device of any one of the preceding items, further comprising an actuating element (24, 25, 26) attached to a distal end of the distal outer segment (22), the distal outer segment (22) adapted to be brought from its unexpanded state to its expanded state in response to actuation of the actuating element (24, 25, 26). (Item 13) Item 13. The device of item 12, wherein the actuating element is a pulling element (24), and the distal outer section (22) is adapted to be brought from its unexpanded state to its expanded state when the distal end is pulled proximally by the pulling element (24). (Item 14) Item 13. The device according to item 12, wherein the actuating element is a pushing element (25), and the distal outer section (22) is adapted to be brought from its expanded state to its unexpanded state when the distal end is pushed distally by the pushing element (24). (Item 15) Item 13. The device of item 12, wherein the actuating element is a coiled thread (26) adapted to expand radially within the region of the distal outer section (22) when compressed longitudinally. (Item 16) A method for intraluminal neurovascular intervention using a device comprising a catheter (2) having a proximal outer section (21) with a first diameter (D1) and a distal outer section (22) with a second diameter (D2), in particular using a device as described in any one of the previous items, comprising at least a.) inserting said catheter (2) along its longitudinal length into the circulatory system (CS) of said human or animal patient; b.) aspirating one or several blood clots (C) present in the circulatory system (CS) through the catheter (2); Including, a distal outer section (22) of the catheter (2) having an unexpanded state in which the second diameter (D2) is smaller than the first diameter (D1) and a radially expanded state; the distal outer section (22) being in its unexpanded state during step a.) to facilitate passage of the catheter (2) through the circulatory system (CS); said distal outer section (22) being in its expanded state during step b.); A method comprising: [Brief description of the drawings]

[0059] Preferred embodiments of the present invention are described below with reference to the drawings, which are for purposes of illustrating the present preferred embodiments of the present invention and not for purposes of limiting the same.

[0060] [Figure 1a] FIG. 1a shows a side view of a catheter of a device according to a first embodiment of the invention with a partially cut and open outer shell structure in a non-expanded state of the distal outer section.

[0061] [Figure 1b] FIG. 1b shows the catheter of FIG. 1a in an expanded state of the distal outer section.

[0062] [Figure 1c] FIG. 1c shows a variation of an inner tubular element that may be used in combination with the catheter of FIG. 1a.

[0063] [Figure 1d] FIG. 1d shows another variation of an inner tubular element that may be used in combination with the catheter of FIG. 1a.

[0064] [Figure 2a] FIG. 2a shows a side view of a catheter of a device according to a second embodiment of the invention with a partially cut and open outer shell structure in an unexpanded state of the distal outer section.

[0065] [Figure 2b] FIG. 2b shows the catheter of FIG. 2a in an expanded state of the distal outer section.

[0066] [Figure 3a] FIG. 3a shows a side view of a catheter of a device according to a third embodiment of the invention with the outer shell structure partially cut and open in an expanded state of the distal outer section.

[0067] [Figure 3b]FIG. 3b shows the catheter of FIG. 3a in a distal outer section unexpanded state.

[0068] [Figure 4a] FIG. 4a shows a side view of a catheter of a device according to a fourth embodiment of the invention with the outer shell structure partially cut and open in the unexpanded state of the distal outer section.

[0069] [Figure 4b] FIG. 4b shows the catheter of FIG. 4a in a partially expanded state of the distal outer section.

[0070] [Figure 4c] FIG. 4c shows the catheter of FIG. 4a in an expanded state of the distal outer section.

[0071] [Figure 5a] FIG. 5a shows a side view of a catheter of a device according to a fifth embodiment of the invention with the outer shell structure partially cut and open in the unexpanded state of the distal outer section.

[0072] [Figure 5b] FIG. 5b shows the catheter of FIG. 5a in a partially expanded state of the distal outer section.

[0073] [Figure 5c] FIG. 5c shows the catheter of FIG. 5a in an expanded state of the distal outer section.

[0074] [Figure 6a] FIG. 6a shows a side view of a catheter of a device according to a sixth embodiment of the invention, with an actuating element in the form of an inner coiled screw made visible, in a non-expanded state of the distal outer section.

[0075] [Figure 6b] FIG. 6b shows the catheter of FIG. 6a in a partially expanded state of the distal outer section.

[0076] [Figure 6c] FIG. 6c shows the catheter of FIG. 6a in an expanded state of the distal outer section.

[0077] [Figure 7a] FIG. 7a shows a side view of a catheter of an apparatus according to an eighth embodiment of the invention in a non-expanded state of the distal outer section.

[0078] [Figure 7b] FIG. 7b shows the catheter of FIG. 7a in an expanded state of the distal outer section.

[0079] [Figure 8a] FIG. 8a shows a side view of a catheter of a device according to a ninth embodiment of the invention in a relaxed expanded state of the distal outer section.

[0080] [Figure 8b] FIG. 8b shows the catheter of FIG. 8a in an expanded state of the distal outer section.

[0081] [Figure 9a] FIG. 9a shows a perspective view of a catheter of a device according to a tenth embodiment of the invention in a relaxed expanded state of the distal outer section.

[0082] [Figure 9b] FIG. 9b shows a perspective view of a distal end portion of a pushing element used in combination with the catheter of FIG. 9a.

[0083] [Figure 9c] FIG. 9c shows a perspective view of a spring clip attached to the catheter of FIG. 9a and serving to hold the pushing element of FIG. 9b in a rolled up configuration as used in FIG. 9a, in a flattened configuration.

[0084] [Figure 10a] FIG. 10a shows a side view of a catheter with an inserted pushing element of a device according to an eleventh embodiment of the invention in a relaxed expanded state of the distal outer section.

[0085] [Figure 10b] FIG. 10b shows the catheter of FIG. 10a with a pushing element that is releasably attached to the catheter using an elastic loop.

[0086] [Figure 10c] FIG. 10c shows the catheter of FIG. 10a with an elastic loop attached to the distal end of the catheter.

[0087] [Figure 11] FIG. 11 shows a side view of a catheter with inserted pushing element of a device according to a twelfth embodiment of the invention in a relaxed expanded state of the distal outer section.

[0088] [Figure 12a] FIG. 12a shows a side view of a catheter with inserted pushing element of a device according to a thirteenth embodiment of the invention in a relaxed expanded state of the distal outer section.

[0089] [Figure 12b] FIG. 12b shows the catheter of FIG. 12a with a pushing element that is releasably attached to the catheter using a spiral coil and an elastic loop.

[0090] [Figure 13a] FIG. 13a shows a side view of a catheter of a device according to a fourteenth embodiment of the invention in a relaxed expanded state of the distal outer section with a loop attached to the distal end of the catheter.

[0091] [Figure 13b] FIG. 13b shows the catheter of FIG. 13a with a pushing element releasably attached to the loop and inserted into the catheter in such a way that it applies a pulling force to bring the distal outer section to its unexpanded state.

[0092] [Figure 14a] FIG. 14a shows a side view of a catheter of a device according to a fifteenth embodiment of the invention in a relaxed expanded state of the distal outer section, with a pushing element inserted into the catheter and releasably connected to it via a rear wire.

[0093] [Figure 14b] FIG. 14b shows the catheter of FIG. 14a with a pushing element that is anchored to the rear wire in such a way that the pushing element applies a pulling force on the distal end of the catheter to bring the distal outer section into its unexpanded state.

[0094] [Figure 15] FIG. 15 shows a reinforcing element for the catheter of the inventive device in the form of a braided structure.

[0095] [Figure 16] FIG. 16 shows a first variation of the knitting pattern of the knitted reinforcement element for the catheter of the inventive device.

[0096] [Figure 17] FIG. 17 shows a second variation of the knitting pattern of the knitted reinforcement element for the catheter of the inventive device.

[0097] [Figure 18] FIG. 18 shows the crochet pattern of the crochet reinforcing element for the catheter of the inventive device.

[0098] [Figure 19] FIG. 19 shows a biaxial braid of a braided reinforcement element for the catheter of the inventive device.

[0099] [Figure 20] FIG. 20 shows a triaxial braid of a braided reinforcement element for the catheter of the inventive device.

[0100] [Figure 21a]FIG. 21a shows a supporting structure for forming a reinforcing element of the catheter of the inventive device in a contracted state.

[0101] [Figure 21b] FIG. 21b shows the support structure of FIG. 21a in an expanded state.

[0102] [Figure 22] FIG. 22 shows a cutting pattern to provide another supporting structure for forming a reinforcing element for the catheter of the inventive device.

[0103] [Figure 23] FIG. 23 shows a cutting pattern to provide yet another supporting structure for forming a reinforcing element for the catheter of the inventive device.

[0104] [Figure 24a] FIG. 24a shows a first step in the treatment of ischemic stroke using a device as shown in FIGS. 1a and 1b, with a guidewire extending through the clot.

[0105] [Figure 24b] FIG. 24b shows a second step in the treatment of ischemic stroke with a device as shown in FIGS. 1a and 1b, with the guidewire and distal outer segment of the catheter in its unexpanded state extending through the clot.

[0106] [Figure 24c] FIG. 24c shows a third step in the treatment of ischemic stroke with a device as shown in FIGS. 1a and 1b, with the catheter in a partially expanded state, partially retracted, and with the clot retriever deployed and engaged with the clot.

[0107] [Fig. 24d]FIG. 24d shows a fourth step in the treatment of ischemic stroke with a device as shown in FIGS. 1a and 1b, with the catheter in its expanded state and with the clot retriever still engaged with the clot.

[0108] [Figure 24e] FIG. 24e shows a fifth step in the treatment of ischemic stroke using a device as shown in FIGS. 1a and 1b, with the clot retriever and the clot received within the expanded catheter being retracted from the blood vessel.

[0109] [Figure 25a] FIG. 25a illustrates diagrammatically the insertion of a guidewire into a patient's circulatory system for the treatment of ischemic stroke.

[0110] [Figure 25b] FIG. 25b diagrammatically illustrates partial insertion of an inventive catheter into the circulatory system along the guidewire of FIG. 25a, with the distal outer section of the catheter in an unexpanded state.

[0111] [Figure 25c] FIG. 25c diagrammatically shows the catheter of FIG. 25b advanced further into the vasculature, such as for extension, with the non-expanded distal outer segment through a clot in the internal carotid artery.

[0112] [Figure 25d] FIG. 25d diagrammatically shows the catheter of FIGS. 25b and 25c in an unexpanded state and partially retracted to deploy the clot retriever engaged with the clot.

[0113] [Figure 25e] FIG. 25e diagrammatically shows the catheter of FIGS. 25b, 25c, and 25d in an expanded state, ready to aspirate a blood clot.

[0114] [Fig. 25f]FIG. 25f diagrammatically shows the catheter of FIGS. 25b, 25c, and 25d in an expanded state after retraction of the clot retriever and clot under application of suction force into the catheter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0115] Description of the Preferred Embodiments In the figures, elements of different embodiments but having the same or similar function and / or design are designated with the same reference numbers.

[0116] In Figs. 1a-23 several embodiments and variants of the inventive device are shown, in particular catheters of such devices for intraluminal neurovascular intervention, in particular for the treatment of ischemic stroke.

[0117] 1a and 1b show a first embodiment of the inventive clot retrieval device catheter 2. The catheter 2 has a generally tubular structure along most of its entire longitudinal length for insertion into the circulatory system of a human or animal patient. Through the inner lumen of the catheter 2, various devices, in particular a clot retriever, can be advanced to the site of a cerebral vascular interruption.

[0118] The catheter 2 comprises a proximal outer section 21 and a distal outer section 22. The longitudinal length of the proximal outer section 21 typically exceeds that of the distal outer section 22 by a factor of several. The distal outer section 22 is directly connected to the proximal outer section 21. The proximal outer section 21 preferably forms the proximal end (not shown in the figures) of the catheter 2, which typically remains outside the patient during the intervention. The proximal end comprises a first opening, which gives access to the inner lumen of the catheter 2. The distal end 221 of the catheter 2 is formed by the distal outer section 22. The distal end 211 comprises a second opening, which gives access to the inner lumen of the catheter 2. Apart from the first and second openings at the proximal and distal ends, the catheter preferably does not have any further openings. The catheter 2 is thus capable of advancing suction from the first opening at the proximal end to the second opening at the distal end.

[0119] The proximal outer section 21 and the distal outer section 22 form the radially outermost part of the catheter 2. In this embodiment, an elastic shell structure 223 completely covers both the proximal outer section 21 and the distal outer section 22. Radial collapse of the catheter 2 is prevented in the proximal outer section 21 by the inner tubular element 23. The inner tubular element 23 is completely, i.e. along its entire length, covered on the outside by the elastic shell structure 223. The inner tubular element 23 is here, i.e. in this embodiment, formed by a tightly wound coil 231. The design of the inner tubular element 23 in the form of the coil 231 allows, on the one hand, the catheter 2 to have the desired flexibility for passage through the vasculature. On the other hand, the coil 231 provides the catheter 2 with a certain radial resistance that prevents the catheter 2 from radially collapsing when a suction force, i.e. a vacuum, is applied through its inner lumen. Instead of comprising a coil 231, the inner tubular element 23 may also be formed by a hypodermic tube as known in the art.

[0120] As can be seen from the combined views of Figures 1a and 1b, the distal outer section 22 of the catheter 2 has an unexpanded state (Figure 1a) and a radially expanded state (Figure 1b). The distal outer section 22 has an outer diameter D2 that is substantially enlarged when the distal outer section 22 is brought from its unexpanded state to its radially expanded state. Also, the inner diameter of the distal outer section 22, i.e., the diameter of the inner lumen, is substantially enlarged in the expanded state compared to the unexpanded state.

[0121] To bring the distal outer section 22 into the expanded state, the inner tubular element 23 needs to be advanced by the clinician relative to the proximal and distal outer sections 21, 22, in particular relative to the outer shell structure 223. The inner tubular element 23 is thus movable along the longitudinal direction relative to the proximal and distal outer sections 21, 22. By advancing the inner tubular element 23 into the distal outer section 22, the generally elastically designed distal outer section 22 is radially expanded and in the expanded state has a diameter D2 identical to the diameter D1 of the proximal outer section 21. When the inner tubular element 23 is retracted, the distal outer section 22 returns again to its non-expanded state due to the elasticity of the outer shell structure 223.

[0122] In order to achieve sufficient radial stiffness while at the same time allowing the distal outer section 22 to flex, a reinforcing element 222 is provided as part of the distal outer section 22. The reinforcing element 222 is here formed by the braided structure of the distal outer section 22. In the unexpanded state, which is adopted during the insertion process of the catheter 2 into the circulatory system, the reinforcing element 222 gives the distal outer section the flexibility required to be passed through the vascular system of a patient. In the expanded state, the reinforcing element 222 prevents radial collapse of the distal outer section 22 during the aspiration process.

[0123] In both the expanded and unexpanded states, the outer diameters D1 and D2 are constant along the entire length of the respective proximal or distal outer segments 21, 22. Thus, in both the expanded and unexpanded states, the proximal outer segment 21 and the distal outer segment 22 each have the general form of a hollow cylinder. The diameter D1 of the proximal outer segment 21 remains the same independently of whether the distal outer segment 22 is in the unexpanded or expanded state.

[0124] In particular, note that the inner and outer diameters within the region of the transition between the proximal outer segment 21 and the distal outer segment 22 are constant along the length in the expanded state of the distal outer segment 22, and decrease continuously from the proximal outer segment to the distal outer segment in the unexpanded state of the distal outer segment. Thus, there are no abrupt changes or discontinuities in the inner and outer diameters within the transition in both the expanded and unexpanded states of the distal outer segment 22.

[0125] The coil 231 of the inner tubular element 23 can be formed, for example, from a wire made of a metal or polymer. The wire can have a cross-sectional profile that is rounded, in particular circular, or rectangular, in particular flat. Alternatively, the inner tubular element 23 can be constructed from a laser cut or patterned tube, or from a flexible tube made from a thermoplastic or composite.

[0126] The proximal end of the inner tubular element 23 is preferably connected to a handling means for the clinician to facilitate sliding of the inner tubular element 23 relative to the outer sections 21, 22 of the catheter 2. This allows the tubular structure to be slid from the larger diameter proximal outer section 21 into the smaller diameter distal outer section 22, D2, as shown in FIG. 1b, thus causing expansion of the distal outer section 22. The presence of the inner tubular element 23 within the expanded distal outer section 22 adds additional hoop strength to the distal outer section 22, making it more resistant to collapse when exposed to radial forces such as those in the case of negative pressure or vacuum.

[0127] The mesh-like reinforcing element 222 of the distal outer section 22 is formed by a braided structure, which may in particular be made from Nitinol (NiTi). The outer shell structure 223 is preferably made from a polymer.

[0128] Figures 1c and 1d show variants for the inner tubular element 23 of the embodiment of Figures 1a and 1b. Instead of being in the form of a coil 231, the inner tubular element 23 can also be in the form of a continuous wire forming a rib-like structure, as shown in figure lc. The rib-like structures formed by the wire extend over at least a part of the circumference in alternating circumferential directions in each case. In this embodiment, the rib-like structures each have a rectangular shape. In other embodiments, the rib-like structures can of course also have other shapes, such as rounded shapes. A further variant of the inner tubular element 23 is shown in Figure 1d. The inner tubular element 23 is here in the form of a plurality of C-shaped elements that are attached, in particular welded, to a longitudinally extending wire. In another variant, the C-shaped elements can also be circumferentially closed, i.e. O-shaped. The variants of FIGS. 1c and 1d have the advantage that the inner tubular element 23 is radially compressible to a certain extent, which may lead to a smoother transition from the proximal outer section 21 to the distal outer section 22.

[0129] Figures 2a and 2b show an embodiment of the inventive catheter 2 which differs from the one of Figures 1a and 1b by not having an inner tubular element 23 but instead having a pulling element 24 as an actuating element for transforming the distal outer section 22 from a non-expanded state as shown in Figure 2a to an expanded state as shown in Figure 2b. Here, the pulling element 24, provided in the form of a pulling thread, is attached to the distal end 221 of the distal outer section 22 and extends along the entire length of the catheter 2 so that it can be handled by the clinician during the intervention.

[0130] The distal outer segment 22 is in its unexpanded state, as shown in Figure 2a, unless a pulling force is applied to the pulling element 24. However, when a pulling force is applied to the pulling element 24 by the clinician, the pulling element 24 longitudinally compresses the distal outer segment 22 relative to the proximal outer segment 21. As a result of the longitudinal compression, the distal outer segment 22 is radially expanded (Figure 2b).

[0131] In the embodiment of Figures 3a and 3b, instead of the pulling element 24, a pushing element 25 is provided as actuating element. The pushing element 25, here provided in the form of a pushing screw, is attached to the distal end 221 of the distal outer section 22. The reinforcing element 222, in this embodiment in the form of a braided structure, holds the distal outer section 22 in its expanded state when no force is applied by the pushing element 25. Thus, in the relaxed state, the distal outer section 22 is expanded as shown in Figure 3a. By applying a pushing force to the pushing element 25, the distal outer section 22, which is attached to the proximal outer section 21, is stretched in the longitudinal direction, which causes a radial contraction of the reinforcing element 222 and thus of the proximal outer section 21.

[0132] 4a-4c, a first distal end of the reinforcing element 222 is attached to the outer shell structure 223 and a second proximal end of the reinforcing element 222 is attached to the inner tubular element 23. Also, in this embodiment, the reinforcing element 222 is formed by a braided structure. The outer shell structure 223 in this case preferably has some radial elasticity, but it does not have any longitudinal elasticity or only a minor one.

[0133] In the relaxed state, the distal outer section 22 is unexpanded, as shown in Figure 4a. By moving the inner tubular element 23 distally and forward relative to the proximal and distal outer sections 21, 22, the reinforcing element 222 is compressed longitudinally and, as a result, radially expanded, as shown in Figure 4b, until the fully expanded state of the distal outer section is reached, as shown in Figure 4c.

[0134] In an alternative embodiment, the inner tubular element 23 of the embodiment shown in FIGS. 4a - 4c abuts only against the proximal end of the reinforcing element 222, i.e., does not attach to the braided structure but to an element that attaches to or is attached to the proximal end of the reinforcing element 222. This allows the catheter 2 to be advanced to the location required without using the inner tubular element 23. The inner tubular element 23 can then be advanced through the catheter 2 and the distal outer section 22 can be expanded when it reaches the desired location within the patient's body.

[0135] The embodiment of FIGS. 5a - 5c differs from only one of FIGS. 4a - 4c herein by the inner tubular element 23 which is in the form of a subcutaneous tube instead of a tightly wound coil.

[0136] FIGS. 6a - 6c show a further embodiment of the catheter 2. In this case, the distal outer section 22 is again formed of an elastic material that gives the distal outer section 22 a non - expanded form as shown in FIG. 6a in the relaxed state. In this embodiment, a coiled screw - in body 26 is arranged within the inner lumen of the catheter 2, particularly within the distal outer section 22. The distal end of the coiled screw - in body 26 is attached to the distal end 221 of the distal outer section 22. The coiled screw - in body 26 is adapted to expand radially within the region of the distal outer section 22 when, for example, longitudinally compressed by a clinician as shown in FIG. 6b. By doing so, the coiled screw - in body 26 radially expands the distal outer section 22 until an expanded state is reached (FIG. 6c).

[0137] The coiled screw - in body 26 is preferably made of a shape - memory material, particularly a shape - memory alloy such as nitinol. Due to the shape - memory material, the coiled screw - in body 26 is preferably adapted to adopt the configuration as shown in FIG. 6c with an expanded radius and a greater number of windings present within the region of the distal outer section 22 when longitudinally compressed.

[0138] Figures 7a and 7b show a further embodiment of the catheter 2, with the unexpanded state of the distal outer segment 22 shown in Figure 7a and the expanded state shown in Figure 7b. In the expanded state, the outer diameter D2 of the distal outer segment 22 is identical to the outer diameter D1 of the proximal outer segment 21. However, in the unexpanded state of Figure 7a, the diameter D2 of the distal outer segment 22 is multiple times smaller than the diameter D1 of the proximal outer segment 21.

[0139] In its relaxed state, the distal outer section 22 can be in either an unexpanded state, as shown in FIG. 7a, or an expanded state, as shown in FIG. 7b.

[0140] The catheter 2 of Figures 7a and 7b has a reinforcing element 222, in the form of a braided structure, provided along the entire distal outer section 22, in this embodiment at least along the distal end portion of the proximal outer section 21. The reinforcing element 222 not only ensures the flexibility required for the distal outer section 22 to be passed through the patient's vasculature, but also improves the mechanical stiffness and resistance of the catheter 2 to torque and column strength. In the expanded state of the distal outer section 22, the reinforcing element 222 is adapted to resist a vacuum applied within the inner lumen of the catheter 2, thus preventing the catheter 2 from collapsing. Furthermore, the reinforcing element 222 is adapted to radially expand when longitudinally compressed and / or radially contract when longitudinally stretched. The reinforcing element 222 is thus adapted to effect a change of the distal outer section 22 from a non-expanded state to an expanded state (and vice versa). For this purpose, an actuation element in the form of a pushing or pulling element (not shown in Figures 7a, b) can be attached, in particular releasably attached, to the distal end 221 or to the proximal end of the distal outer section 22.

[0141] The distal end 221 of the distal outer section 22 can be reinforced with a circumferential stiffening wire 224, as shown in Figure 7b. A pushing or pulling element can be attached to the stiffening wire 224.

[0142] 8a and 8b show an embodiment of a catheter 2 having a design like the embodiment of Figs. 7a and 7b, but additionally comprising a semi-cylindrical spring structure 225 fixedly attached to the distal end 221 of the distal outer section 22 with an attachment element 229. The semi-cylindrical spring structure 225 extends coaxially along the central longitudinal axis of the catheter 2 and can be radially compressed by rolling up the structure more. In the compressed state, as shown in Fig. 8b, the semi-cylindrical spring structure 225 adopts a nearly perfect cylindrical shape with a through slit extending along the entire length of the structure.

[0143] In its radially compressed state, the semi-cylindrical spring structure 225 can be received by a receiving cylinder 251, which forms the distal end of the pushing element 25. The pushing element 25 can be, for example, a pushing tube or a pushing screw. The receiving cylinder 251 is closed in the proximal direction by an end face. When received by the receiving cylinder 251, the semi-cylindrical spring structure 225 abuts proximally against this end face. Thus, the semi-cylindrical spring structure 225, and thus the distal end 221 of the distal outer section 22, can be pushed distally by the pushing element 25 in order to longitudinally extend the distal outer section 22. Due to the reinforcing element 222, i.e. the braided structure, the distal outer section 22 is radially contracted when being longitudinally extended in order to adopt its non-expanded state.

[0144] In use, the catheter 2 of Figures 8a and 8b is inserted into and passed through the patient's circulatory system with the pushing element 25 extending along the entire inner lumen of the catheter 2 and the semi-cylindrical spring structure 225 received within the receiving cylinder 251 to longitudinally stretch the distal outer segment 22 and hold it in its unexpanded state. After reaching a desired location within the circulatory system, the pushing element 25 can be partially retracted from the catheter 2 to bring the distal outer segment to its expanded state for clot aspiration. The retraction can be such that the semi-cylindrical spring structure 225 remains within the receiving cylinder 251 to allow for subsequent longitudinal stretching of the distal outer segment 22. Alternatively, the pushing element 25 can be fully retracted from the catheter 2 to initiate the aspiration process, possibly with the aid of a clot retriever advanced through the catheter 2 for clot retrieval.

[0145] 9a-9c show an embodiment of a catheter 2 with a pointed distal end 221. In a relaxed state, the distal outer section 22 of the catheter 2 is in its expanded state, as shown in FIG. 9a. To bring and hold the outer distal section 22 in its unexpanded state for passing the catheter 2 through the circulatory system of a patient, a pushing element 25 with a widened end 252 is provided. The pushing element 25, which may in particular be a pushing tube, is guided all the way through the catheter 2, the widened end 252 being engaged by a spring clip 26 that is attached to the distal end 221 of the distal outer section 22 by means of an attachment element 229. By pushing the pushing element 25 distally further into the catheter 2, the distal outer section 22 is stretched longitudinally due to the attachment of the widened end 252 to the spring clip 226. As a result, due to the reinforcing element 222 in the form of a braided structure, the distal outer section 22 is radially contracted. The spring clip 226 can be formed by rolling a simple rectangular plate, as shown in FIG. 9c.

[0146] In a different embodiment, the distal outer section 22 of the catheter 2 of Fig. 9a can be in its unexpanded state when relaxed. The actuating element for bringing the distal outer section 22 to the expanded state can then be a pulling element instead of a pushing element. By pulling the pulling element proximally, the distal outer section 22 will be compressed longitudinally due to the attachment of the pulling element to the spring clip 226 and due to the stiffening element 222, and will consequently be expanded radially.

[0147] 10a-10c show an embodiment with a catheter 2 having a pointed distal outer section 22. As in the embodiment of Figs. 9a-9c, the catheter 2 also comprises a reinforcing element 222 in the form of a braided structure that holds the distal outer section 22 in its expanded state when relaxed. To radially contract the distal outer section 22, a pushing element 25, e.g. a pushing screw or a pushing tube, is guided along and all the way through the catheter 2 and is attached to the distal end 221 of the distal outer section 22 by means of an elastic loop 227. The elastic loop 227 is fixedly attached to the distal end 221 of the catheter 2 and holds the pushing element 25 by means of friction. A portion of the outer surface of the pushing element 25 can include a friction-enhancing coating to improve the attachment of the pushing element 25 to the loop 227. If a friction-enhancing coating is provided only on one side of the pushing element 25, the pushing element 25 can be rotated to release the attachment. The loops 227 can be interwoven with the reinforcing element 222, ie, the braided structure.

[0148] FIG. 11 shows a further option for releasably attaching the pushing element 25 to the distal end 21 of the catheter 2. A loop 253 is now attached to the distal end of the pushing element 25. To radially contract the distal outer section 22, the pushing element 25 is inserted into the catheter 2 or the like where the loop 253 is engaged by a hooked element 228 attached to the distal end 221 of the catheter 2. As in the case of FIG. 11, the hooked element 228 can be in the form of a simple stiff wire extending proximally from the distal end 221 into the inner lumen of the catheter 2. By engaging the loop 253 with the hooked element 228 and further pushing the pushing element 25 along the distal direction relative to the catheter 2, the distal outer section is stretched longitudinally and, as a result, radially contracted due to the braided reinforcing element 222.

[0149] Yet another option for releasably attaching the pushing element 25 to the distal end 221 of the catheter 2 is shown in Figures 12a and 12b. In this embodiment, a coil spring 254 with a first end is attached to the distal end portion of the pushing element 25. From its attached first end, the coil spring 254 is wound around the pushing element 25 along the proximal direction. The second end is not attached to the pushing element 25 and protrudes slightly from it so that it can be easily inserted into the loop 227 attached to the distal end 221 of the catheter 2. By rotating the pushing element 25, the loop 227 can be further screwed into the coil spring 254 to improve the attachment in such a way that the distal end 221 of the catheter can be moved distally and proximally with the pushing element 25. To release the pushing element 25 from the distal end 221, the pushing element 25 can be rotated in the opposite direction.

[0150] The embodiment shown in Figures 13a and 13b corresponds to one of Figures 10a-10c, except that the distal end 221 is not now pointed, and the distal outer section 22 does not have a cylindrical shape in the unexpanded state. Instead, as shown in Figure 13b, the distal end portion of the distal outer section 22 is contracted and adopts a hemispherical-like shape in the unexpanded state. A loop 227 is formed by the continuation of the stiffening wire 224 for this purpose.

[0151] A particularly preferred embodiment is shown in Figures 14a and b. Figure 14a shows the distal outer section 22 of the catheter 2 in a relaxed expanded state. The distal outer section 22 is held in this expanded state by a braided reinforcing element 222. To radially contract the distal outer section 22, a hollow pushing element 25 in the form of a pushing tube is inserted lengthwise into the catheter 2 in such a way that a rear wire 27 extends through the pushing tube along its entire length. The rear wire 27 is attached to the distal end 221 of the catheter 2. It can be formed by a continuation of the reinforcing wire 224. The pushing element 25 protrudes from the proximal end of the catheter 2. Similarly, the rear wire 27 protrudes from the proximal end of the pushing element 25 so that the physician can operate both the pushing element 25 and the rear wire. The rear wire 27 and the pusher tube 25 can be locked together by drawing the rear wire 27 proximally relative to the catheter 2 so that it is tensioned, and simultaneously advancing the pusher element 25 distally, at least to the attachment point of the rear wire 27, to the distal end 221 of the catheter 2 while holding the rear wire 27 in this position. If the pusher tube 25 is then moved further distally relative to the catheter 2, the distal outer section 22 is stretched longitudinally and contracted radially due to the stiffening element 222 (FIG. 14b). The locking of the rear wire 27 and the pusher tube 25 can be released by releasing the rear wire 27 relative to the catheter 2.

[0152] To facilitate handling for the physician, an actuation tool can be provided in all of the above described embodiments in which the proximal ends of the catheter 2, of the pushing element 25 and, if provided, of the rear wire 27 are arranged in such a way that manipulation as described above to radially contract and / or expand the distal outer section 22 is possible.

[0153] In all of the above-mentioned embodiments comprising a braided structure, any other reinforcing element may also be provided for the same purpose instead of the braided structure, such as, for example, a reinforcing element in the form of one or several spirally wound wires or in the form of interwoven filaments. Further possible variants of at least one reinforcing element are shown in Figures 15-23.

[0154] 15 shows a reinforcing element 222 in the form of a knitted structure. With a knitted structure, a relatively significant radial expansion or contraction can be achieved, accompanied by even minor longitudinal changes in the structure.

[0155] Figures 16 and 17 show two possible variations of knitting patterns that can be used in knitted structures like the one shown in Figure 15. By using weft knitting (Figure 16) or warp knitting (Figure 17), the directional elasticity of the knitted structure, i.e., the reinforcing elements 222, can be controlled in such a way that some elasticity is provided in the radial direction and no, or only reduced, elasticity is provided in the longitudinal direction.

[0156] Another alternative variant for the reinforcing element 222 is a crocheted structure as shown in Figure 18. As with knitted structures, directional elasticity can be provided with the crocheted structure in such a way that the elasticity of the structure is much more pronounced in the radial direction than in the longitudinal direction.

[0157] Further alternative variants for the reinforcing element 222 are shown in Figs. 19 and 20 in the form of a biaxial braid (Fig. 19) and a triaxial braid (Fig. 20). In a biaxial braid, the filaments are arranged in two different directions. In the present case of Fig. 19, the angle between the two filament directions is approximately 90°. Such a braid expands radially when it is shortened longitudinally. If another set of filaments is oriented in a third direction during braiding, a triaxial braid results, such as the one shown in Fig. 20. The third set of filaments can be used, for example, to limit longitudinal movement in response to radial expansion and contraction.

[0158] Figures 21a and 21b show further variants of the reinforcing element 222, now formed by an auxiliary structure or material. With the aid of an auxiliary structure or material it is possible to provide a reinforcing element 222 for the distal outer section 22 which is radially expanded when stretched longitudinally (Figure 21b) or radially contracted when compressed longitudinally (Figure 21a). Such structures, with a negative Poisson's ratio, can be obtained, for example, by means of specific cutting patterns such as the one shown in Figures 21a, b.

[0159] 22 and 23 show two additional types of cutting patterns that can be used to provide support structure to form the reinforcing element 222. The patterns can be cut, for example, from plastic or metal tubing and are known as re-entrant support patterns.

[0160] In Figures 24a-24e and 25a-25f, method steps for retrieval of a blood clot C from a patient's intracranial vasculature and from its circulatory system CS are shown on a larger scale (Figures 25a-25f) and in more detail (Figures 24a-24e). In the examples of Figures 24a-24e and 25a-25f, clot removal is achieved using suction and with a clot retriever 3 engaging the clot C. However, in other situations, the use of a clot retriever may not be necessary and the clot may be removed using only suction into the catheter.

[0161] Figures 24a and 25a diagrammatically illustrate the insertion and positioning of a guidewire 1 into the circulatory system CS of an animal or, as in the illustrated situation, a human patient. In particular, the way in which the guidewire 1 is inserted into the circulatory system from within the region of the femoral artery FA of the patient can be seen in Figure 25a. From the point of insertion in the femoral artery FA, ​​the guidewire 1 is advanced through the aorta into the internal carotid artery ICA and the middle cerebral artery MCA to the location of the clot C. The location of the clot C has been previously identified, for example, using X-ray computed tomography. The passage of the guidewire 1 through the circulatory system CS is performed according to state-of-the-art methods. The guidewire 1 can, for example, be equipped with fluoroscopic markers for this purpose. The guidewire 1 is passed to the target location in such a way that it extends along the blood vessel BV and through the clot C along its longitudinal extension.

[0162] In the next step shown in Figure 25b, the catheter 2 is inserted and advanced with the aid of the previously positioned guidewire 1 so that the distal outer section 22 of the catheter 2 is positioned to extend through the clot C (Figures 24b and 25c).

[0163] The guidewire 1 is then retracted and replaced by a delivery wire 4. The delivery wire 4 has a distal end to which a clot retriever 3 is attached. The clot retriever 3 is adapted to engage the clot C to remove it from the circulatory system and preferably has the form of a stent retriever as known by those skilled in the art. However, the clot retriever 3 can also have other forms and in particular be provided with a plurality of clot engaging elements as disclosed in the yet unpublished European Patent Application No. EP 19 167 604.8 of the same applicant.

[0164] In a next step, the catheter 2 is partially retracted to deploy the clot retriever 3 engaged with the clot C (FIGS. 24c and 25d). Alternatively, or in addition, the delivery wire 4 with the clot retriever 3 can also be advanced distally for deployment.

[0165] To enable clot aspiration through the catheter 2, the distal outer section 22 is then brought from its unexpanded state to its expanded state with the distal opening 221 positioned directly proximal to the clot C, as shown in Figures 24d and 25e.

[0166] 24e and 25f, the clot retriever 3 and delivery wire 4 with the clot C are retracted into the catheter 2. At the same time, suction of the clot C through the catheter 2 is applied to assist the retraction process.

[0167] Finally, the catheter 2 is completely retracted from the circulatory system with the clot C still being held by both the clot retriever 3 and preferably by the vacuum still applied within the inner lumen of the catheter.

[0168] List of References [ka]

Claims

1. A device for neurovascular intraluminal intervention, comprising: The device comprises a catheter (2) for insertion along its longitudinal length into the circulatory system (CS) of a human or animal patient, the catheter (2) having a proximal outer section (21) having a first diameter (D1) and a distal outer section (22) having a second diameter (D2); The catheter (2) is adapted to aspirate one or several blood clots (C) present in the circulatory system (CS), The apparatus comprises: the distal outer section (22) of the catheter (2) having a non-expanded state for facilitating passage of the catheter (2) through the circulatory system (CS) in which the second diameter (D2) is smaller than the first diameter (D1), and a radially expanded state for facilitating aspiration of the one or more blood clots (C) through the catheter (2); the catheter (2) further comprising an inner tubular element (23) for bringing the distal outer section (22) from its unexpanded state to its expanded state; the distal outer section (22) comprises a braided structure (222) and an outer shell structure (223), the braided structure (222) adapted to radially expand when longitudinally compressed by moving the inner tubular element (23) toward the distal end of the outer shell structure (223); An apparatus comprising:

2. A device for neurovascular intraluminal intervention, comprising: The device comprises a catheter (2) for insertion along its longitudinal length into the circulatory system (CS) of a human or animal patient, the catheter (2) having a proximal outer section (21) having a first diameter (D1) and a distal outer section (22) having a second diameter (D2); The catheter (2) is adapted to aspirate one or several blood clots (C) present in the circulatory system (CS), The apparatus comprises: the distal outer section (22) of the catheter (2) having a non-expanded state for facilitating passage of the catheter (2) through the circulatory system (CS) in which the second diameter (D2) is smaller than the first diameter (D1), and a radially expanded state for facilitating aspiration of the one or more blood clots (C) through the catheter (2); The apparatus, an actuation element (24, 25, 26) attached to a distal end of the distal outer section (22), the distal outer section (22) adapted to be brought from its unexpanded state to its expanded state upon actuation of the actuation element (24, 25, 26); a releasable attachment that allows the working element to be removed from the catheter after expanding the distal outer section; Further providing An apparatus comprising:

3. 3. The device of claim 2, wherein the catheter (2) further comprises an inner tubular element (23) for bringing the distal outer section (22) from its unexpanded state to its expanded state.

4. An apparatus as described in claim 1 or claim 3, wherein the inner tubular element (23) comprises an inner tube that can be moved longitudinally relative to the distal outer section (22).

5. 5. The device of claim 1, 3 or 4, wherein the distal outer section (22) is made of an elastic material that keeps the distal outer section (22) in its unexpanded state when the inner tubular element (23) is arranged outside the distal outer section (22) and is stretched radially outward when the inner tubular element (23) is moved into the distal outer section (22).

6. The device described in claim 1, wherein the braided structure (222) is attached to the inner tubular element (23) having a first end and to a distal end of the outer shell structure (223) having a second end.

7. The device of any one of claims 3 to 5, wherein the distal outer section (22) comprises a braided structure (222) and an outer shell structure (223), the braided structure (222) being attached to the inner tubular element (23) having a first end and to a distal end of the outer shell structure (223) having a second end, and the braided structure (222) is adapted to expand radially when compressed longitudinally by moving the inner tubular element (23) toward the distal end of the outer shell structure (223).

8. The device according to any one of claims 1, 3 to 7, wherein the inner tubular element (23) comprises a coil (231).

9. The apparatus described in claim 8, wherein the coil (231) extends along the entire longitudinal length of the inner tubular element (23).

10. 3. The device of claim 2, wherein the actuating element is a pulling element (24), and the distal outer section (22) is adapted to be brought from its unexpanded state to its expanded state when the distal end is pulled in a proximal direction by the pulling element (24).

11. 3. The device of claim 2, wherein the actuating element is a pushing element (25), and the distal outer section (22) is adapted to be brought from its expanded state to its unexpanded state when the distal end is pushed in a distal direction by the pushing element (25).

12. 3. The device of claim 2, wherein the actuating element is a coiled thread (26), the coiled thread (26) adapted to expand radially within the region of the distal outer section (22) when compressed longitudinally.

13. The device described in any one of claims 1 to 12, wherein the device is for the treatment of ischemic stroke.

14. The apparatus of any one of claims 1 to 13, further comprising a clot retriever (3) adapted to be positioned within the circulatory system (CS) with the catheter (2) to engage one or more clots (C) present within the circulatory system (CS) and to be retracted within the expanded distal outer section of the catheter (2).

15. The device of any one of claims 1 to 14, wherein in the expanded state, the second diameter (D2) of the distal outer section (22) is the same as or greater than the first diameter (D1) of the proximal outer section (21).

16. The device of any one of claims 1 to 15, wherein the distal outer section (22) has an essentially cylindrical shape along its entire longitudinal length in the unexpanded state.

17. The device described in claim 16, wherein in the expanded state, the distal outer section (22) has an essentially cylindrical shape along its entire longitudinal length.

18. The device according to any one of the preceding claims, wherein the distal outer section (22) comprises at least one reinforcing element (222).

19. The device of claim 18, wherein the at least one reinforcing element (222) has a braided structure adapted to expand radially when compressed in the longitudinal direction, or to contract radially when stretched in the longitudinal direction, or to expand radially when stretched in the longitudinal direction, or to contract radially when compressed in the longitudinal direction.

20. The device of any one of claims 1 to 19, wherein the distal outer section (22) is adapted to be brought from its unexpanded state to its expanded state and from its expanded state to its unexpanded state.

21. The device of any one of claims 1 to 20, wherein in a non-expanded state of the distal outer section (22), the transition of the catheter (2) from the proximal outer section (21) to the distal outer section (22) is defined by a continuously decreasing outer and / or inner diameter.

22. A device for intraluminal neurovascular intervention, comprising a catheter (2) having a proximal outer section (21) having a first diameter (D1) and a distal outer section (22) having a second diameter (D2); a) the catheter (2) is configured to be inserted along its longitudinal length into the circulatory system (CS) of a human or animal patient; b) said catheter (2) is adapted to aspirate one or several blood clots (C) present in said circulatory system (CS); The apparatus comprises: the distal outer section (22) of the catheter (2) having an unexpanded state in which the second diameter (D2) is smaller than the first diameter (D1), and a radially expanded state; the distal outer section (22) being in its unexpanded state during insertion of the catheter (2) into the circulatory system (CS) to facilitate passage of the catheter (2) through the circulatory system (CS); said distal outer section (22) being in its expanded state while aspirating said one or several blood clots (C); the catheter (2) further comprising an inner tubular element (23) for bringing the distal outer section (22) from its unexpanded state to its expanded state; the distal outer section (22) comprises a braided structure (222) and an outer shell structure (223), the braided structure (222) adapted to radially expand when longitudinally compressed by moving the inner tubular element (23) toward the distal end of the outer shell structure (223); An apparatus comprising:

23. A device for neurovascular intraluminal intervention, comprising a catheter (2) having a proximal outer section (21) having a first diameter (D1) and a distal outer section (22) having a second diameter (D2); a) the catheter (2) is configured to be inserted along its longitudinal length into the circulatory system (CS) of a human or animal patient; b) said catheter (2) is adapted to aspirate one or several blood clots (C) present in said circulatory system (CS); The apparatus comprises: the distal outer section (22) of the catheter (2) having an unexpanded state in which the second diameter (D2) is smaller than the first diameter (D1), and a radially expanded state; the distal outer section (22) being in its unexpanded state during insertion of the catheter (2) into the circulatory system (CS) to facilitate passage of the catheter (2) through the circulatory system (CS); said distal outer section (22) being in its expanded state while aspirating said one or several blood clots (C); The apparatus, an actuation element (24, 25, 26) attached to a distal end of the distal outer section (22), the distal outer section (22) adapted to be brought from its unexpanded state to its expanded state upon actuation of the actuation element (24, 25, 26); a releasable attachment that allows the working element to be removed from the catheter after expanding the distal outer section; Further providing An apparatus comprising:

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