Expandable opening catheter

Abstract

The present invention is entitled "Expandable Opening Catheter." The present invention discloses a catheter system that is actuable to an expanded state and includes a catheter body and a dilator positioned at least partially within the lumen of the catheter. The distal end of the dilator is releasably connectable to the distal tip of the catheter body. The dilator is retractable to expand and invert the distal tip and form a funnel shape in the expanded state.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 898,864, filed September 11, 2019, the contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure generally relates to devices and methods for removing acute blockages from blood vessels during endovascular medical treatments. More particularly, the present disclosure relates to expandable catheters for aspirating clots. Background Art

[0004] Clot retrieval catheters and devices are frequently used in mechanical thrombectomy for endovascular intervention in patients with conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing distant areas, such as neurovascular beds, is challenging using conventional techniques because the target vessels are small in diameter, distal to the insertion site, and highly tortuous.

[0005] The clot itself can complicate the procedure by taking on a variety of complex morphologies and consistencies, ranging from simple tubular structures that take the shape of a blood vessel to long, chain-like arrangements that can span multiple vessels simultaneously. The age of the clot can also affect its compliance, with older clots tending to be less compressible than fresh clots. Fibrin-rich clots also present the challenge of sticky properties that can cause the clot to roll along the outer surface of a mechanical thrombectomy device rather than being effectively gripped. Combinations of soft and hard clot regions can also be separated during aspiration, where rupture can lead to distal embolism, which can occur in vessels that are inaccessible to currently available devices. Furthermore, disrupting the adhesion of the clot to the vessel wall without damaging the delicate vessel is a significant challenge.

[0006] Conventional clot retrieval catheters, especially those designed for operation in neurovascular settings, can have a number of disadvantages. First, the diameter of the catheter itself must be small enough to avoid causing significant discomfort to the patient. The catheter must also be flexible enough to navigate the vasculature and withstand high strains, while also having axial stiffness to provide smooth propulsion along the route. Once the target site is reached, the size of a typical object to be retrieved from the body can be substantially larger than the catheter tip, making it more difficult to retrieve the object into the tip. For example, fibrin-rich clots are often difficult to extract because they can deposit at the tip of a conventional fixed-opening catheter. This deposition can cause the softer portions of the clot to break away from the harder areas, leading to distal embolism.

[0007] The small diameter and fixed tip size can also be less efficient in the aspiration necessary to remove blood and thrombotic material during guided surgery. The aspiration suction must be strong enough so that any fragmentation that occurs through the use of a mechanical thrombectomy device or other methods can be kept minimally stationary so that the debris cannot migrate and obstruct distal vessels. However, when aspirating with a conventional fixed-opening catheter, a significant portion of the aspiration flow ultimately comes from the vascular fluid near the catheter tip, where there is no clot. This significantly reduces aspiration efficiency, thereby reducing the success rate of clot removal.

[0008] The design disclosed in the present invention aims to provide an improved suction retrieval catheter that solves the above-mentioned drawbacks. Summary of the Invention

[0009] The present invention aims to provide systems, devices, and methods that meet the aforementioned needs. The design focuses on an expandable catheter with an expandable clot-facing opening for flow restriction, improved aspiration efficiency, and easy clot retrieval, while also having a collapsed state that is low-profile and flexible enough for delivery within a standard sheath or external catheter. The catheter may also have a custom variable stiffness body segment that incorporates deliverability enhancements over existing designs and is capable of traversing tortuous regions of the vasculature to reach occluded clots.

[0010] In some examples, a catheter system capable of being actuated to an expanded state is disclosed. The system can include a catheter body having a lumen. A dilator can be positioned at least partially within the lumen, with a distal end of the dilator connected to a distal tip of the catheter body. The dilator can be retractable to expand and invert the distal tip to form a funnel shape in the expanded state.

[0011] In some examples, the distal tip can include a proximal segment and a substantially flexible distal segment extending from the proximal segment. The proximal end of the distal segment can extend from the proximal segment and can include a pull ring adjacent to and / or connected to the distal end of the distal segment.

[0012] In some examples, a midpoint of the distal segment in the collapsed state transitions to a distal-most atraumatic end of the funnel shape in the expanded state that is distal to the catheter body.

[0013] In some examples, the distal segment can be substantially tubular in the collapsed state and can include the funnel shape in the expanded state.An air cushion can be formed by the funnel shape between the distal end and the pull ring.

[0014] In some examples, the distal segment can be divided into a proximal braid portion and a distal helical portion.

[0015] In some examples, the expander can include a proximal segment, and a distal segment located distal to the proximal segment can have a diameter greater than the proximal segment, and the distal segment can include a contact element that extends radially outward from the distal segment of the expander and is configured to contact and translate the pull ring proximally until aligned at or near the proximal end of the distal segment of the expander.

[0016] In some examples, the contact element can include an interference fit with the distal end of the distal tip of the catheter body.

[0017] In some examples, the distal segment of the dilator can include a maximum diameter at a contact element and gradually decreases from the contact element to the distal end of the distal segment.

[0018] In some examples, the distal section of the dilator has a maximum diameter at the contact element and tapers from the contact element to a junction between the proximal and distal sections of the dilator.

[0019] In some examples, the proximal section of the dilator is highly flexible or significantly more flexible than the distal section of the dilator.

[0020] In some cases, the dilator can include a substantially flexible segment extending distally of the more rigid distal segment, the substantially flexible segment being a short nose.

[0021] In some examples, the proximal section of the expander can include a fiber reinforcement system to resist elongation.

[0022] In some examples, the expander can include a proximal segment and a distal segment located distal to the proximal segment. The distal segment of the expander can have a maximum diameter that is larger than the proximal segment. The distal segment of the expander can include a distal contact element that extends radially outward from the distal segment and is configured to contact and translate the pull ring proximally until it is aligned at or near the proximal end of the distal segment. The proximal contact element of the expander can be spaced proximally from the distal contact element and extend radially outward from the distal segment and is configured to contact and translate the pull ring proximally, and the proximal contact element can have a diameter that is smaller than the distal contact element. The pull ring can be connected between the contact elements.

[0023] In some examples, the pull ring is positionable in a gap between the contact elements.

[0024] In some examples, the contact element can include an interference fit with the distal end of the distal tip when in the funnel shape in the expanded state.

[0025] In some examples, at least one of the contact elements includes a magnetic connector operable to magnetically retract the distal tip to the funnel shape of the deployed state.

[0026] In some examples, the proximal and / or distal segments of the dilator can include substantially thinned walls.

[0027] In some examples, the proximal segment can include a rope-like filament configured to resist elongation under tension.

[0028] In some examples, the proximal segment of the distal tip can be more rigid than the distal segment.

[0029] In some examples, the distal segment can be more rigid than the proximal segment.

[0030] In some cases, the distal segment can include a resistance for maintaining a substantially tubular shape prior to deployment.

[0031] In some examples, the proximal segment and / or the distal segment of the distal tip can include a braided structure.

[0032] In some examples, the proximal segment and / or the distal segment of the distal tip can include a memory alloy.

[0033] In some examples, the distal segment of the distal tip in the collapsed state can be substantially tubular and in the expanded state can include the funnel shape, with the funnel shape forming an air cushion between the distal end and the pull ring.

[0034] In some examples, the expander can include a proximal segment and a distal segment distal to the proximal segment. The distal segment can include a distal contact element extending radially outward from the distal segment and configured to contact and proximally translate the pull ring until aligned at or near the proximal end of the distal segment of the distal tip. The pull ring can include a magnetic connector. The proximal end of the distal tip is magnetized to attract the pull ring, thereby causing the distal tip to retract into the funnel shape.

[0035] In some examples, the proximal end of the distal tip and the pull ring are locked together in the deployed state, including but not limited to corresponding magnets locking together.

[0036] In some examples, the proximal end of the distal tip and the pull ring each include a planar mating surface.

[0037] In some examples, the proximal end of the distal tip and the pull ring each include mating surfaces having profiled ridges and / or interlocking recesses.

[0038] In some examples, the proximal end of the distal tip and the pull ring each include mating surfaces that are tapered for tapered locking interaction.

[0039] In some examples, the proximal end of the distal tip and the pull ring each include mating surfaces configured to snap-lock together.

[0040] In some examples, the pull ring has a similar diameter to the catheter body such that an abutment is formed between the pull ring and the catheter body in the deployed state. The distal tip can extend distally from an inner diameter of the pull ring and around an outer diameter of the pull ring to extend proximally over the catheter body.

[0041] In some examples, the distal tip can include a proximal segment and a distal segment extending from the proximal segment. The distal segment of the distal tip can be substantially flexible and include a proximal end positioned on an outer surface of the distal tip. The distal segment of the distal tip can include a pull ring adjacent to or just distal to the distal segment. The distal tip can be configured to interact between the pull ring and a distal surface of the catheter body.

[0042] In some examples, the proximal end of the distal segment of the distal tip can be external to the pull ring.

[0043] In some examples, the distal tip can be integral with the catheter body. The distal tip can include a proximal segment and a distal segment extending from the proximal segment. The distal segment can be substantially flexible and include a proximal end that is substantially aligned with a pull ring within the distal segment when configured into a funnel shape.

[0044] In some examples, the dilator can include a substantially tubular proximal segment and a distal segment located distal to the proximal segment. The distal segment of the dilator can have a diameter greater than that of the proximal segment. The distal segment of the dilator can include a contact element extending radially outward from the distal segment and configured to contact and proximally translate the pull ring until aligned at or near the distal end of the proximal segment at the distal tip.

[0045] In some examples, the contact element can be an outwardly angled latch.

[0046] In some examples, the contact element can be an orthogonally outward-facing latch.

[0047] In some examples, the contact element can be located distal to the proximal end of the distal segment.

[0048] In some examples, the midpoint of the distal segment of the distal tip in the collapsed state transitions to the distal-most petal end of the funnel shape in the expanded state, distal to the catheter.

[0049] In some examples, the midpoint of the distal segment of the distal tip in the collapsed state transitions to the distal-most flower petal end of the funnel shape in the expanded state, distal to the catheter.

[0050] In some examples, the expander can include a proximal segment and a distal segment distal to the proximal segment. The distal segment can include a distal contact element extending radially outward from the distal segment and configured to contact and proximally translate the pull ring until aligned at or near the proximal end of the distal tip.

[0051] In some examples, the expander can include a proximal contact element that tapers proximally from the distal contact element. The proximal contact element can have a diameter smaller than the distal contact element. In some examples, the distal contact element can be an outwardly extending ring-shaped member. In some examples, the distal contact element can include a semicircular shape. In some examples, the distal contact element can be connected to the pull ring.

[0052] In some examples, the midpoint of the distal segment in the collapsed state transitions to the distal-most petal ends of the funnel shape in the expanded state, distal to the catheter.

[0053] In some examples, the midpoint of the distal segment in the collapsed state transitions to the distal-most flower petal end of the funnel shape in the expanded state, distal to the catheter.

[0054] In some examples, the expander can include a proximal segment and a distal segment located distal to the proximal segment. The distal segment can have a larger maximum diameter than the proximal segment and can have a larger diameter than the proximal segment. A distal contact element can include a transition from the distal segment to the proximal segment and be configured to contact and translate the pull ring proximally to create an interference fit with the pull ring, thereby transmitting a force to expand the distal tip into the funnel shape.

[0055] In some examples, the distal tip is configured to first expand into a substantially conical shape before inverting to form the funnel shape.

[0056] In some examples, the proximal section of the dilator is highly flexible and includes thin walls.

[0057] In some instances, the proximal segment of the dilator is highly flexible and includes longitudinal rope fibers to prevent the proximal segment from stretching under tension.

[0058] In some examples, when the inverted funnel shape is formed, an interference force between the dilator and the pull ring cannot cause the pull ring to move proximally.

[0059] In some examples, the dilator tip can be squeezed through a pull ring.

[0060] In some instances, the dilator tip is easily retracted through the catheter.

[0061] In some examples, the dilator tip can include a proximal segment and a distal segment extending from the proximal segment. The distal segment can be substantially flexible and positioned at least partially around the proximal segment, the proximal segment being located at least at a proximal end of the distal segment. The distal tip can include a pull ring that can include an outer taper that mates with an inner taper of the proximal segment such that the tapers lock together when forming the funnel shape.

[0062] In some examples, the braid extends circumferentially at a midpoint of the distal tip to help define a rounded inverted seam.

[0063] In some examples, the braid extends from a proximal end to a distal end of the distal tip, thereby providing a rounded inverted seam.

[0064] In some examples, the braid includes a subset of filaments extending from a proximal portion to a middle portion, such that the filaments invert to extend back to the proximal portion, thereby forming a looped braid pattern, and the remaining filaments extend from a proximal end to a distal end, such that a helical portion is formed distal to the looped subset of filaments.

[0065] In some examples, the braid includes filaments extending in a helical configuration from a proximal portion to a distal portion.

[0066] In some examples, the braid includes an inverted hinge in or around the middle portion.

[0067] In some examples, the proximal portion can be relatively rigid, the intermediate portion can be relatively flexible, and the distal portion can include a flexible helix.

[0068] In some examples, the distal tip can include a braid having a proximal portion, a mid-portion, and a distal portion, wherein the distal portion has sufficient radial force to urge the proximal portion radially outward while being configured to accommodate various vessel sizes in an atraumatic manner.

[0069] In some examples, a method of inverting an expandable catheter in a blood vessel is disclosed. The method can include advancing the catheter to a target site; and retracting a distal tip of the catheter via a dilator positioned at least partially within a lumen of the catheter, causing the distal tip to expand and invert into a funnel shape.

[0070] In some examples, the method can include restricting flow in the blood vessel via the funnel shape.

[0071] In some cases, the method can include withdrawing the dilator from the catheter; applying suction through the catheter to stimulate a thrombus to enter the funnel-shaped opening; and withdrawing the catheter with the captured thrombus from the patient.

[0072] In some cases, the method can include capturing an occluding thrombus with a mechanical thrombectomy device; and withdrawing the thrombectomy device into the funnel shape of the catheter.

[0073] In some cases, the dilator can be unnecessary.In such methods, the collapsed tip can be plugged onto the clot, and the suction force can pull the distal end proximally to invert the tip and form the inverted funnel shape during suction.

[0074] Other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art after reviewing the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The above and other aspects of the present disclosure will be further discussed through the following description of the accompanying drawings, in which like reference numerals indicate like structural elements and features throughout the various figures. The drawings are not necessarily drawn to scale, with emphasis placed on illustrating the principles of the present disclosure. The drawings depict one or more specific implementations of the present invention by way of example only and not limitation. It is expected that those skilled in the art will be able to conceive and combine elements from the various drawings to better meet the needs of the user.

[0076] Figure 1A The expandable tip of an expandable catheter is depicted in a first configuration with a dilator of the present disclosure.

[0077] Figure 1B Depicts an expandable catheter in a position having Figure 1A Another configuration of an expandable tip of the expander.

[0078] Figure 1C Depicts an expandable catheter in a position having Figure 1A Another configuration of an expandable tip of the expander.

[0079] Figure 2A Depicts deployment to a target location according to aspects of the present disclosure. Figures 1A to 1C The expandable tip of the expandable catheter.

[0080] Figure 2B Depicts deployment to a target location according to aspects of the present disclosure. Figures 1A to 1C The expandable tip of the expandable catheter.

[0081] Figure 2C Depicts deployment to a target location according to aspects of the present disclosure. Figures 1A to 1C The expandable tip of the expandable catheter.

[0082] Figure 2D Depicts deployment to a target location according to aspects of the present disclosure. Figures 1A to 1C The expandable tip of the expandable catheter.

[0083] Figure 3A The expandable tip of an expandable catheter is depicted in a first configuration with a dilator of the present disclosure.

[0084] Figure 3B Depicts an expandable catheter in a position having Figure 3A Another configuration of an expandable tip of the expander.

[0085] Figure 4A The expandable tip of an expandable catheter is depicted in a first configuration with a dilator of the present disclosure.

[0086] Figure 4B Depicts an expandable catheter in a position having Figure 4A Another configuration of an expandable tip of the expander.

[0087] Figure 5A The expandable tip of an expandable catheter is depicted in a deployed configuration with a dilator of the present disclosure.

[0088] Figure 5B The expandable tip of an expandable catheter is depicted in a deployed configuration with a dilator of the present disclosure.

[0089] Figure 5C The expandable tip of an expandable catheter is depicted in a deployed configuration with a dilator of the present disclosure.

[0090] Figure 6AThe expandable tip of an expandable catheter is depicted in a deployed configuration with a dilator of the present disclosure.

[0091] Figure 6B The expandable tip of an expandable catheter is depicted in a deployed configuration with a dilator of the present disclosure.

[0092] Figure 6C The expandable tip of an expandable catheter is depicted in a deployed configuration with a dilator of the present disclosure.

[0093] Figure 7A Describes the aspects of the present disclosure. Figure 6B The expandable tip of the expandable catheter.

[0094] Figure 7B Describes the aspects of the present disclosure. Figure 6B The expandable tip of the expandable catheter.

[0095] Figure 7C Describes the aspects of the present disclosure. Figure 6B The expandable tip of the expandable catheter.

[0096] Figure 8A Depicted is an expandable tip of an expandable catheter deployed according to aspects of the present disclosure.

[0097] Figure 8B Describes the aspects of the present disclosure. Figure 8A The expandable tip of the expandable catheter.

[0098] Figure 8C Describes the aspects of the present disclosure. Figures 8A to 8B The expandable tip of the expandable catheter.

[0099] Figure 9A The expandable tip of an expandable catheter is depicted in a deployed configuration with a dilator of the present disclosure.

[0100] Figure 9B Describes the Figure 9A The expandable tip is in a deployed configuration with the expander removed.

[0101] Figure 10A An expandable tip of an expandable catheter in a first configuration is depicted according to aspects of the present disclosure.

[0102] Figure 10B is in an expanded configuration according to aspects of the present disclosure Figure 10A Close-up of the expandable tip of the .

[0103] Figure 11AThe expandable tip of an expandable catheter is depicted in a first configuration with a dilator of the present disclosure.

[0104] Figure 11B Depicts an expandable catheter in a position having Figure 11A Another configuration of an expandable tip of the expander.

[0105] Figure 12A Depicted is a side view of an expandable tip of an expandable catheter in one configuration according to the present disclosure.

[0106] Figure 12B Depicted is another configuration according to the present disclosure Figure 12A Rear view of the expandable tip of the .

[0107] Figure 12C Depicted according to the present disclosure Figure 12B Side view of the expandable tip of .

[0108] Figure 12D Depicted according to the present disclosure Figure 12B Front view of the expandable tip of the .

[0109] Figure 13 Depicted is a side view of an expandable tip of an expandable catheter in one configuration according to the present disclosure.

[0110] Figure 14A Depicted is a side view of an expandable tip of an expandable catheter in one configuration according to the present disclosure.

[0111] Figure 14B Depicted is another configuration according to the present disclosure Figure 14A Rear view of the expandable tip of the .

[0112] Figure 14C Depicted according to the present disclosure Figure 14B Side view of the expandable tip of .

[0113] Figure 14D Depicted according to the present disclosure Figure 14B Front view of the expandable tip of the .

[0114] Figure 15A Depicted is a side view of an expandable tip of an expandable catheter in one configuration according to the present disclosure.

[0115] Figure 15B Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0116] Figure 15C Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0117] Figure 16A Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0118] Figure 16B Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0119] Figure 16C Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0120] Figure 16D Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0121] Figure 16E Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0122] Figure 16F Depicted according to the present disclosure Figure 15A A close-up view of the expandable tip of the

[0123] Figure 17 is a flow chart outlining a method of using the system according to aspects of the present disclosure. DETAILED DESCRIPTION

[0124] The object of the solution of the present disclosure is an invertible expandable catheter having a large distally facing opening and a customized highly flexible body segment capable of traveling through tortuous regions of the vasculature to reach occlusive clots, capable of providing both local flow restriction / blocking. The flow restriction and large tip design provide significantly greater aspiration efficiency. Such advantages are also particularly beneficial in stroke intervention procedures, where the vessels in the neurovascular bed are particularly small and tortuous, and thus the customized axial and bending stiffness profile can inhibit kinking and binding. The catheter is also compatible with a relatively low profile access sheath and outer catheter, so that a puncture wound in the patient's groin (in the case of femoral access) can be easily and reliably closed. The catheter may also have internal and / or external low friction lining features, as well as an outer polymer sheath or membrane disposed around the support structure.

[0125] These improvements can lead to safer and faster access of catheters and other devices to complex areas to remove blockages and shorten surgical procedures.While the present description is in many cases in the context of mechanical thrombectomy treatments, these systems and methods may also be applicable to other procedures and other body passages.

[0126] Accessing the various vessels within the vascular system (whether coronary, pulmonary, or cerebral) involves well-known surgical procedures and the use of many conventional, commercially available ancillary products. These products, such as angiographic materials, rotary hemostatic valves, and guidewires, are widely used in laboratories and medical procedures. While these products are used in conjunction with the systems and methods of the present disclosure described below, their function and exact configuration are not described in detail.

[0127] See the attached figure, Figures 1A to 1C , a method for removing an occlusive clot C (e.g., Figures 2A to 2D The catheter system 100 is shown in FIG. 1 . The system 100 may be a conventionally constructed aspiration catheter or may have rapid exchange (RX) type features, many of which may greatly increase the speed and efficiency of the clot retrieval procedure. Specifically, Figures 2A to 2D The catheter body 50 of the catheter 100 is shown expanded into the target blood vessel BV according to aspects of the present disclosure. The system 100 may be actuated to Figure 1C The expander 70 can be positioned at least partially within the lumen 47 of the catheter body 50. The distal end 78 of the expander 70 can be connected to the distal tip 51 of the catheter body 50. The expander 70 can be retractable to invert the distal tip 51 and form a funnel shape in the expanded state, such as when the system is opened. Figure 1A The initial extension state moves toward the proximal side for one or more distances D to Figure 1C The expanded state is shown in . Figure 1C While the expanded state is shown, the expander 70 will be completely removed prior to aspiration to maximize the flow possible through the distal end 51 of the catheter body and to allow passage of the microcatheter and stent retriever. The expander 70 may also include a distally projecting microcatheter portion so that the stent retriever can be exposed across the clot during activation of the funnel and removal of the expander 70.

[0128] For an approximately 2 mm catheter body OD in M1, the ratio of collapsed OD to expanded funnel OD is expected to be in the range of approximately 2.5 mm to 4.0 mm. At the carotid T, this ratio is expected to be in the range of 4.0 mm to 6.0 mm. Where the ratio is expected to be in the range of 5.0 mm to 8.0 mm, this ratio is feasible for ICA vessel placement. Where the ratio is expected to be in the range of 2.5 mm to 5.0 mm, this ratio is envisioned for the targeted M1 and carotid T locations.

[0129] In some examples, the ratio between the collapsed OD and the funnel OD depends on the length of the corresponding catheter tip when collapsed. Preferably, for an expanded OD of approximately 2.5 mm to 5.0 mm, the collapsed tip length can range from 3 mm to 8 mm (e.g., distance D in the figures). However, in some examples, this ratio can be a function of the braid diameter and braid angle of the braid.

[0130] The system 100 can be configured to expand to a wide range of target vessel diameters, such as the distal carotid artery (3.2 mm to 5.2 mm), the horizontal segment M1 of the middle cerebral artery (1.6 mm to 3.5 mm), and / or the internal carotid artery (ICA, 2.7 mm to 7.5 mm). If the catheter system 100 is subsequently retracted from the M1 segment to the ICA (or another path with an increasing vessel inner diameter toward the proximal end), once the tip 50 is in the funnel shape, its radial force can continue to seal with the vessel over a wide range of vessel sizes. In addition, the tip 50, which can accommodate a variety of target vessel diameters, can also seal at vessel bifurcations, which may have a wider cross-sectional area than the vessel proximal to the bifurcation and the vessel distal to the bifurcation. Preferably, the tip 51 is inverted into the expanded funnel shape at the treatment site to avoid having to advance the funnel-shaped catheter tip through the vasculature.

[0131] The ideal nominal diameter of the catheter system 100 depends on the location of the target clot and / or the diameter of any other catheters through which the catheter system 100 will be delivered. To retrieve a clot in an intracranial vessel of the cerebral vascular bed, where the vessel diameter at the M1 position is typically approximately 3 mm, a suitable system may have an outer catheter with an inner diameter of 0.065" to 0.080" and an RX clot retrieval catheter with an inner diameter of 0.055" to 0.070". When deployed, the maximum diameter of the tip 50 can be at least 2.5 mm (but in some cases up to 8 mm), allowing it to seal against the wall of the vessel and provide a funnel-shaped distal opening as large as the vessel itself. In some cases, the tip 51 can also provide an opening large enough to oppose bifurcations and / or proximal vessel locations. This seal, combined with the maximum proximal lumen of the disclosed RX system, provides benefits in terms of suction force at the clot face and increased flow rate due to the larger inner diameter design of the outer catheter compared to conventional catheters.

[0132] In some examples, the distal tip 51 can include a proximal segment 55 and a distal segment 52 extending from the proximal segment 55. The segment 52 can be substantially flexible, and the proximal end 53 of the distal segment 52 can extend from the proximal segment 55 and include a pull ring 54 adjacent to and / or connected to the distal end 58 of the distal segment 52. In this example, the pull ring 54 can be positioned on the proximal side 54 of the distal end within the distal segment 52. In this regard, the segment 52 can be an expandable sheath attached below the pull ring 54.

[0133] When the expander 70 is moved proximally a distance D while being connected to the distal end 58, Figure 1A The midpoint of the collapsed distal segment 52 can be transformed into a distal portion of the catheter body 50. Figure 1C The distal end of the funnel-shaped in the expanded state is atraumatic. The distal segment 52 in the collapsed state can be a substantially tubular ( Figure 1A ), and moves toward the near side by a distance D( Figure 1B 、 Figure 1C ) in the expanded state after segment 52 may include a funnel shape.

[0134] In some examples, the funnel shape formed by the inverted distal segment 52 can include an air cushion 60 formed between the distal end 58 and the pull ring 54. In some examples of this funnel shape, the ring 54 can be positioned inside the lumen 47 to form a compression lock therewith, thereby securing the segment 52 in its expanded funnel shape. The compression lock can be defined as an interference fit by fitting the ring 54 within the lumen 47, the inner diameter of which can be slightly smaller than the outer diameter of the ring 54.

[0135] In some examples, the distal segment 52 can be divided into a proximal braid portion and a distal spiral braid portion. The elastic membrane can be interwoven, coated on the braid or inverted frame structure, or extend above it. For example, the elastic membrane can follow the contour of the underlying braided strut frame of the end 51. The elastic membrane can at least partially cover the length of the end 51. In other examples, the end 51 can also be coated with a lubricating material, such as a commercially available hydrophilic coating (e.g., Surmodics, Harland, Biocoat, Covalon), or can include a low-friction material or filler. The membrane can also float above the inverted support structure so that the inverted structure struts can move freely below the membrane. In some examples, the membrane encapsulates the inverted support structure.

[0136] In some examples, the expander 70 can include a proximal segment 76 and a distal segment 77 extending distally therefrom. Segment 77 can have a larger diameter than the proximal segment 76 and include a contact element 71 that extends radially outward to contact the pull ring 54 and translate the pull ring proximally by one or more distances D until aligned at or near the proximal end 53 of the distal segment 52. In this example, the contact element 71 can be an abrupt, angled outward transition that creates a contact surface that forms an interference fit with the distal end 58 of the segment 52.

[0137] In some examples, the expander 70 can be solid and / or hollow (having a lumen therein). The expander 70 can include an inner lumen 75 that is substantially elongated (e.g., tubular) at a proximal segment 76 of the expander and then tapers radially outward to a distal segment 77 having a distal end 78 having a larger diameter than the proximal segment 76. The taper can begin at the transition between segments 76, 77 or at a junction 73. The expander 70 can be highly flexible proximal to the distal end 51. The expander 70 can include one or more fibers as part of its structure that are configured for reinforcement to prevent the expander from stretching. In some examples, segment 76 can be highly flexible or substantially more flexible than distal segment 77. Distal segment 77 can still be sufficiently flexible to twist around tortuous vasculature in some examples. Any rigid portion required to transmit force to the ring 54 can be kept as short as possible to maintain the lateral flexibility of the distal end 51.

[0138] In one example, the system 100 may use a suction source to capture the clot, such as Figures 2A to 2D Specifically, Figures 2A to 2D The system 100 is shown deploying and then aspirating a clot C, preferably as Figure 2D The main advantage of using the dilator 70 as shown and described is that it can be removed after the distal end is inverted so that the entire cross-sectional area of ​​the catheter 50 can be used to maximize the flow through the catheter body 50 and the force on the clot C when in the funnel shape, as shown. Figures 2A to 2D As shown, the funnel shape formed by the expansion of the tip 51 can seal with the wall of the blood vessel BV, or one or more seals can be selectively activated (eg, by moving the dilator 70 proximally or distally).

[0139] Once expanded, the distal end 51 may include a large, atraumatic opening for effective suction. The distal end 51 may include anti-kink features to aid in advancing it to the target location. Thus, as described herein, it may have a variety of configurations or be made of a variety of materials in order to maintain lateral flexibility but avoid expansion or kinking during compression. Figures 2A to 2D The large distal opening of the tip 51 shown can provide improved performance over conventional fixed opening designs, which can be hindered by causing firm, fibrin-rich clots to become lodged in the tip and / or by causing softer portions of the clot to be sheared away. Clot is less likely to become lodged in the tubular portion of the disclosed invertible expandable tip 51 due to the gradual compression of the clot as it enters the reduced funnel shape.

[0140] The struts of tip 51 can be formed from nitinol or another shape-memory material with sufficient elastic strain so that the elastic limit is not exceeded when the tip is constrained and delivered in a collapsed configuration within an external catheter or during expansion to invert into a funnel shape. These struts can be heat-set and expanded only to facilitate inversion at a predetermined location, with the expansion area limited by the outer membrane covering. In this regard, the active inversion frame then pushes the membrane outward by increasing the radial force of the frame. In another embodiment, the frame can be constructed from wire, allowing the use of non-superelastic materials such as stainless steel alloys, as the wires will be free to move independently of each other. It should be understood that the frame of tip 51 constructed from wire using superelastic or shape-memory materials is also contemplated, providing improved torque and durability characteristics. In another embodiment, the frame of tip 51 can be laser-cut or formed from wire from non-superelastic or shape-memory materials that accommodate strain by including cells or bends, where a lower degree of strain is required to move from the collapsed state for delivery to the expanded state for clot retrieval. For example, the frame may include additional cells, longer cell struts, and / or lower cell angles to reduce strain requirements.

[0141] Figures 3A to 3B Another invertible expandable tip 251 is depicted, which is Figure 3A The first configuration shown begins with the expander 270 and then to Figure 3B A close-up of the funnel-shaped expanded configuration of the distal end 251 without the expander 270 is shown. Although the expander 270 is not shown, it may be included as needed or desired. Figure 3B. It should be understood that similar reference numeral examples discussed throughout this disclosure indicate identical or functionally similar elements. Thus, the expander 270 can include an inner cavity 275 having a proximal segment 276 and a distal segment 277 terminating in a distal end 278 distal to the proximal segment 276. The expander 270 can include a distal contact element 271 extending radially outward from the distal segment 277. The element 271 can be configured to contact and translate the pull ring 254 until aligned at or near the proximal end 258 of the distal segment 252. The expander 270 can also include an abrupt angled outward transition (e.g., where the element 271 is substantially orthogonal to the outer surface of the expander 270) to form a contact surface that forms an interference fit with the distal end 258 of the segment 252. The expander 270 may also have a proximal contact element 273 that is spaced proximally from the distal contact element 271 and similarly extends radially outward from the distal segment 277. In some examples, a groove may be defined between the elements 271, 273, in which the pull ring 254 may be positioned or otherwise connected. In this regard, the space between the elements 271, 273, or the opposing faces of the groove, may be planar or otherwise conform to the shape of the ring 254. In some examples, the element 271 may be pushed onto or otherwise coupled to the end 258, while the element 273 may be pushed onto or otherwise coupled to the ring 254. In some examples, the element 273 may have a smaller diameter than the element 271, or vice versa. The expander 270 may taper to a smaller diameter from the element 271 to the distal end 278.

[0142] As in system 100, an interference fit can be provided in catheter body 250 between distal end 258 of distal tip 251 when in the funnel shape of the deployed state. In some examples, at least one of contact elements 271, 273 can include a magnetic connector that is operable to magnetically retract distal tip 251 into the funnel shape of the deployed state. In this way, the magnetic coupling therein can facilitate actuation of tip 271 into the inverted funnel shape of the deployed state. Segment 276 and / or segment 277 can include a substantially thinner wall. Preferably, from segment 276 to segment 277, the dilator can include a relatively thinner wall proximal to the tip for optimal flexibility.

[0143] In some examples, segment 276 may include a rope-like filament configured to prevent elongation under tension. Relative to end 251, its proximal segment 255 may be more rigid than distal segment 252. However, this example is not limited thereto. Conversely, segment 252 may be more rigid than proximal segment 255. In some examples, segment 252 may include a resistance or bias for maintaining its substantially tubular shape prior to deployment, such as Figure 3A. Similar to segments 152, 155, the proximal segment 255 and / or the distal segment 252 may also include a braided structure. For example, segments 252, 255 may be constructed of a framework comprising struts of a memory alloy. Similar to segment 52, segment 252 may be divided into a proximal braid portion and a distal spiral braid portion, and further include one or more elastomeric coatings or films. The braid portion and spiral portion of this example may be formed, for example, by ending the ends of the clockwise braided wire at a midpoint between the ends of the counterclockwise braided wire, so that the counterclockwise braided wire forms a spiral beyond that point. In some examples, this can be achieved by cutting the clockwise wire of the braid at a position between the ends of the standard braid in a circumferential plane. In another example, the clockwise braid may be looped to extend proximally so that a denser proximal braid is paired with the distal spiral portion.

[0144] Figures 4A to 4B Another invertible expandable tip 351 of the catheter 350 is depicted, which is Figure 4A The first configuration shown begins with the dilator 370 and then ends after the dilator 370 has been retracted to invert the tip 351 into a funnel shape. Figure 4B In this case, the proximal section 355 of the tip 351 may include a distal end 353 that may include a magnetic element that can couple with a corresponding ring 354 that can then be magnetized. The ring 354 shown may be configured to magnetically couple with the end 353 so that the tip 351 can remain in a closed position. Figure 4B In some examples, the ring 354 and / or the end 353 can be made of a ferrous metal so that one is attracted to the other. Alternatively, both features can be magnetic so that the south magnetic pole of one feature engages with the north magnetic pole of the other feature to form a stronger bond than when using ferrous metals. In another embodiment, the expander 370 can include a magnetic feature to engage with the pull ring 354 to provide sufficient force to invert the end 351 into its inverted funnel shape.

[0145] In some examples, the expander 370 can include an inner lumen 575 with a distal segment 377 terminating in a distal end 278 distal to the proximal segment 376, wherein the distal segment and the inner segment have similar diameters. The contact element 371 of the expander 370 can be the distal end of a notch or slot or groove or recess of the expander, and the contact element 372 can be the proximal end of the same notch or slot or groove or recess. In some examples, the element 371 can be magnetic so as to grip the ring 354 (e.g., by constructing the ring 354 from one or more ferrous materials) and pull the ring 354 proximally during retraction of the expander 370. The ring 354, which can be coupled to the end 358, can be positioned between the contact elements relative to the notch or slot or groove or recess and / or its surroundings. As arranged, the distal segment 377 translates the pull ring 354 until aligned at or near the proximal end 358 of the distal segment 352, thereby inverting the segment 352 to form Figure 4B The proximal end 353 of the distal tip 351 and the pull ring 354 can be locked together in the deployed state via a corresponding magnetic coupling therebetween. The proximal end 353 of the distal tip 351 and the pull ring 354 can each include a planar mating surface with shaped ridges and / or interlocking recesses. For example, the mating surfaces can be tapered to provide an interlocking, tapered locking interaction. In other examples, the mating surfaces can be configured to snap together.

[0146] Figure 5A Another invertible expandable tip 451 of the catheter 450 is depicted with a dilator 470. The tip 451 may include a proximal segment 455 and a substantially flexible distal segment 452 extending from the proximal segment 455. A proximal end 453 of the distal segment 452 may be positioned on an outer surface of the distal tip 451. Similar to the previously described tips, a pull ring 454 may be located adjacent to or just distal to the segment 455 so that the ring 454 can be used to pull the segment 452 and invert it into a flexible position. Figure 5A The distal segment 452 may have a funnel shape. In some examples, the proximal end 453 of the distal segment 452 may be external to the pull ring 454. In this regard, the ring 454 and attached proximal end 453 are aligned to the OD of the catheter 450 and the positioning membrane structure is attached to the distal side of the pull ring as shown. This attachment, in turn, allows the membrane to taper smoothly toward the distal side when inverted.

[0147] Figure 5BAnother invertible, expandable tip 551 of a catheter 550 is depicted, having a dilator 570 of the present disclosure. As shown, distal tip 551 can be integral with the catheter body 550, including segment 555 integral with segment 552. This example dilator 570 can also have a maximum diameter at or around contact element 573, which can be an outward protrusion or annular extrusion configured to be disposed within ring 554 and form an interference fit with a distally tapering element from element 573. As shown, ring 554 fits beneath the catheter body 550, with the proximal side of the membrane structure aligned with or integral with the distal side of the catheter body 550, and the membrane structure attached beneath pull ring 554. This attachment, in turn, allows the membrane to smoothly taper distally when inverted.

[0148] Figure 5C Another invertible expandable tip 651 of catheter 650 is depicted in a deployed configuration with dilator 670. As shown, dilator 670 may include a distal segment 677 located distal to proximal segment 676, having a larger diameter than proximal segment 676. The diameter may gradually change to form an elliptical or other curved shape. Distal segment 677 may include a contact element 671 extending radially outward from distal segment 677 and configured to contact and translate pull ring 654 proximally until it aligns at or near the distal end of proximal segment 655. It can be seen that element 671 may be an outwardly angled latch. For example, as shown, element 671 may be angled distally to form an acute angle with the outer surface of dilator 670. This latch, in turn, prevents the distal end of segment 652 from detaching from the dilator in a funnel-shaped manner, as shown.

[0149] Figure 5C Another invertible expandable tip 651 of catheter 650 is depicted in a deployed configuration with dilator 670. As shown, dilator 670 may include an inner lumen 675, a distal segment 677 having a distal end 678 located distal to proximal segment 676, and a larger diameter than proximal segment 676. The diameter may gradually change to form an elliptical or other curved shape. Distal segment 677 may include a contact element 671 extending radially outward from distal segment 677 and configured to contact and translate pull ring 654 proximally until it aligns at or near the distal end of proximal segment 655. It can be seen that element 671 may be an outwardly angled latch. For example, as shown, element 671 may be angled distally to form an acute angle with the outer surface of dilator 670. This latch, in turn, prevents the distal end of segment 652 from detaching from the dilator in a funnel-shaped manner, as shown.

[0150] Figure 5CAnother invertible expandable tip 651 of catheter 650 is depicted in a deployed configuration with dilator 670. As shown, dilator 670 may include an inner lumen 675, a distal segment 677 having a distal end 678 located distal to proximal segment 676, and a larger diameter than proximal segment 676. The diameter may gradually change to form an elliptical or other curved shape. Distal segment 677 may include a contact element 671 extending radially outward from distal segment 677 and configured to contact and translate pull ring 654 proximally until it aligns at or near the distal end of proximal segment 655. It can be seen that element 671 may be an outwardly angled latch. For example, as shown, element 671 may be angled distally to form an acute angle with the outer surface of dilator 670. This latch, in turn, prevents the distal end of segment 652 from detaching from the dilator in a funnel-shaped manner, as shown.

[0151] However, element 671 is not limited thereto and may be substantially orthogonal relative to the outer surface of dilator 670. Element 671 may also be located distal to the proximal end 653 of segment 652, whereby end 653 may be positioned on the outer surface of segment 655. In some examples, the midpoint of distal segment 652 in the collapsed state transitions to the distal-most petal end of the funnel shape in the expanded state that is located distal to catheter 650. In this regard, system 600 may include one continuous petal or multiple radially separated distal-most petal ends forming the funnel shape. In other examples, compared to Figures 5A to 5B In contrast to the rounded funnel shape of FIG60 , the funnel shape of system 600 may be more pointed or less atraumatic.

[0152] Figure 6A Another invertible expandable tip 751 of a catheter 750 of the present disclosure is depicted in a deployed configuration with a dilator 770. As shown, a contact element 771 of the dilator 770 is located distal to and attached to the tip 751 and provides a relatively smooth transition for clot capture and / or the use of a stent retriever therein. By positioning the dilator 770 as shown relative to the tip 751, the inner diameter of the system 700 is reduced due to the distal end 758 of the segment 752 being positioned at least partially within the inner diameter of the system 700. Advantageously, the proximal face of the pull ring 754 abuts the distal face of the catheter body 750, and a membrane / frame can be attached beneath the pull ring 754. In this example, the proximal membrane structure is attached to the OD of the catheter 750, which allows the membrane to smoothly taper distally when inverted.

[0153] Figure 6BDepicted is another inverted expandable end 851 in expanded configuration with dilator 870 of catheter 850 of the present disclosure.As shown, the contact element 871 of dilator 870 is positioned at the distal end of end 851 and is attached to this end.Here, because the end 858 of segment 852 is coaxial with segment 855 in the funnel shape that expands, the internal diameter between segment 855,852 is similar (if unequal) basically.As shown, compared with end 751, end 851 can also comprise relatively sharper edge in funnel shape.Here, advantageously, the proximal side of ring 854 abuts the distal end of catheter body 850, and film / frame is attached to the distal end of ring 854.In addition, this causes the sharper inversion of funnel and the proximal membrane structure that is attached to the OD of catheter 750.

[0154] Figure 6C Another invertible expandable tip 951 of a catheter 950 of the present disclosure is depicted with a dilator 970 in a deployed configuration. As shown, a contact element 971 of the dilator 970 is located distal to the tip 951 and attached thereto. Specifically, the distal contact element 971 extends radially outward from a distal segment 977 and is configured to contact and proximally translate a pull ring 954 until aligned at or near the proximal end 953 of the distal tip 951. The proximal end surface of element 971 can be arranged to contact a ring 954, which can be located distal to the distal end 958 of segment 952. Here, the proximal surface of the ring 954 abuts the distal surface of the catheter body 950, and the membrane / frame is attached to the distal surface of the ring 954, creating a relatively sharper inversion of the funnel.

[0155] As shown, the end 958 may have an offset bend that facilitates contact between the ring 954 and the end 958. In the funnel-shaped configuration shown, the bend may extend proximally before returning distally to force the ring 954 to couple with the proximal side of the element 971. In some examples, the element 971 may include or may be an outwardly extending annular member. The element 971 may also include a semicircular shape.

[0156] 7A to 7C The end 851 is shown, but it has the same Figure 6B The modified, more pointed funnel shape described in Figure 7A The collapsed tubular state changes to Figure 7C Specifically, the expander 870 is coupled to the ring 854 at its respective contact elements. Figure 7B The expander 870 is shown having been retracted a first distance such that the segment 852 begins its expansion as its mid-portion begins to invert. Figure 7CRing 854 is shown having been translated proximally by dilator 870 until it contacts the distal face of segment 855. Segment 852 is then fully inverted into a funnel shape. Here, ring 854 has a similar diameter to segment 855, such that in the expanded state, abutment is formed between ring 854 and segment 855. Advantageously, this minimal difference in inner and outer diameters between the proximal and distal ends of catheter 850 optimizes the catheter's relatively low outer profile and large inner diameter.

[0157] Figures 8A to 8C Another expandable invertible tip 1051 of the catheter 1050 of the present disclosure is shown deployed by inverting in conjunction with a dilator 1070 according to aspects of the present disclosure. Specifically, the tip 1051 is shown as being expanded from Figure 8A The collapsed tubular state changes to Figure 8C The proximal side of element 1071 is connected to ring 1054. Figure 8B The expander 1070 is shown retracted a first distance such that the segment 1052 begins its expansion as its mid-portion begins to invert. Figure 8B In the state, segment 1052 may include a generally conical shape prior to inversion. Figure 8C Ring 1054 is shown having been translated proximally by expander 1070 until disposed proximal to the distal face of segment 1055 (eg, here within segment 1055). Segment 1052 is then fully inverted. Figure 8C The ring 1054 may have a diameter that is smaller than the inner diameter of the segment 1055, such that an abutment is formed between the ring 1054 and the inner surface of the segment 1055 in the expanded state.

[0158] In some examples, segments 1077 of expander 1070 may be ultra-soft to provide sufficient interference with pull ring 1054 to transmit a radial force sufficient to expand and invert segment 1052, as in Figures 8A to 8C In some examples, segment 1076 can be highly flexible so that it does not significantly increase the stiffness of the system. To achieve this, segment 1076 can include relatively thin walls and can include longitudinal rope fibers to prevent it from stretching under tension.

[0159] In some examples, once the Figure 8C If the dilator 1070 is not in the inverted funnel shape shown, the interference force between the dilator 1070 and the ring 1054 may not be sufficient to move the ring 1054 more proximally, and the end of the dilator 1070 (e.g., segment 1077) squeezes through the ring 1054. When the segment 1077 is sized to have a small gap with the lumen of segment 1055, the segment 1077 can be easily retracted through the catheter system 1000. In some examples, the dilator 1070 can be re-advanced to push the ring 1054 distally and invert the funnel shape. Figure 8AIn some examples, although not shown, a second, more rigid dilator may be provided for collapsing the tip 1051 once inverted and expanded within the vessel, where the first dilator 1070 may be present.

[0160] Figures 9A to 9B Another expandable and invertible end 1151 of the catheter 1150 is shown. Specifically, Figure 9A Tip 1151 is shown in an expanded, funnel-shaped configuration with dilator 1170 . Figure 9B 11. The distal end 1151 is shown in the same configuration, but with the dilator 1170 retracted and removed from the distal end 1151. Here, the distal face of element 1171 is coupled to the proximal face of the distal end 1158, such that the distal end 1151 is compressed through the loop 1154. The inner diameter of the distal end 1158 is then coupled to the loop 1154. In this example, coupling the distal end 1158 to the loop 1154 as described and shown allows the distal end 1151 to form a gradually smooth curve for entry of aspirated clots and / or stent retriever devices. Furthermore, sizing the loop 1154 to be smaller than the main catheter body inner diameter of the segment 1155 allows the pull ring 1054 to wedge or lock into place when the segment 1177 of the dilator 1170 is compressed through the loop.

[0161] FIG. 10A to FIG. 10B An end 1251 is shown according to aspects of the present disclosure, whereby Figure 10A The distal end 1251 is shown extended in a tubular configuration, and Figure 10B is a close-up of the tip 1251 after the ring 1254 has been retracted so that the segment 1252 is expanded and inverted into a funnel shape. The ring 1254 may include an outer taper that mates with an inner taper 1259 positioned at the distal end of the segment 1255. Figure 10B As shown more clearly in FIG, corresponding tapered portions can be coupled and / or locked together. FIG. 10A to FIG. 10B Only tapered surfaces are shown, but it is contemplated that other interlocking surfaces may be used as needed or desired.

[0162] Figures 11A to 11B Another expandable end 1351 of the catheter 1350 is depicted, which is Figure 11A Starting with a first tubular configuration having a dilator 1370, and then to Figure 11B The expander 1370 may include a contact element 1371 having a maximum diameter of the expander 1370 and then tapering distally therefrom for gradual radial compression of the clot. Here, the ring 1354 may have a diameter similar to that of the segment 1355 such that the abutment therebetween prevents the ring 1354 from moving proximally into the lumen of the segment 1355, as shown. Figure 11BThe distal end 1358 of segment 1352 is attached within the inner diameter of ring 1354, which provides an interference fit between the end 1358 and / or ring 1354 and element 1371 of dilator 1370. Advantageously, in this example, the difference in inner diameter between segment 1355 and ring 1354 is small, making it less restrictive for clots to enter the lumen of segment 1355.

[0163] Additionally, as shown, by folding segment 1352 to extend distally from the inner diameter of ring 1354 and inverting to extend proximally on the outer diameter of ring 1354, segment 1353 can expand and invert to form a rounded feature for an atraumatic funnel that is configured to interact with and seal against the vessel wall.

[0164] If tip 1351 were made rigid, it would form an overly rounded profile and could kink when collapsed for delivery through an external balloon guide or long introducer sheath. This kink could also prevent tip 1351 from forming a gradual taper in the expanded, funnel-shaped configuration and could create a snag point for the stent retriever in the catheter lumen during retraction. Therefore, configuring tip 1351 with a flexible portion allows it to initially form a soft, compressible, rounded feature in the collapsed configuration that will recover to form a gradual taper extending distally from the inner diameter of ring 1354 to help compress the clot during aspiration and provide an unobstructed path for the stent retriever to collapse during retraction into the catheter lumen.

[0165] Figure 12A An exemplary configuration of an expandable, invertible tip 1451 is depicted, which may include a braid having a proximal segment 1447, an intermediate segment 1445, and a distal segment 1443. The intermediate segment 1445 may include filaments extending from proximally to a transition point with the distal segment 1443, which then invert to extend back proximally, thereby forming a braided pattern. The distal segment 1443 may include filaments extending from proximally to distally in a helical configuration and / or may have sufficient radial force to urge the proximal segment 1447 radially outward while conforming and accommodating various vessel sizes in an atraumatic manner. The helical pattern may allow for a wider range of vessel sizes than a braid, as the helical line creates a helical pattern that is more easily adjustable than a braided pattern. The distal segment 1443 may extend circumferentially at or around the transition between segments 1445, 1443 to help define a less rounded inverted seam at the vessel wall.

[0166] 12B to 12D Depicted is a view of the tip 1451 previously expanded and inverted into a funnel shape according to the present disclosure. Specifically, Figure 12C is a side plan view of tip 1451 with an exemplary coating (although a coating is not necessarily required), and Figure 12D is a front plan view of segment 1451, and Figure 12B is a rear plan view of segment 1451. Figure 12D As shown, segment 1443 and its helical configuration can convert segment 1443 into a helix during inversion. Figure 12C It is also apparent in FIG. 1 that the inverted seam along the lower dashed line depicts a more pointed inverted seam design as compared to a rounded inverted seam that may interact with the vessel wall during use. Figure 12B Segments 1447 and 1445 are shown forming the integrity of the braid and providing an inverted hinge at the transition point between segments 1445, 1443. Although not shown, it is contemplated that a coating or film as described herein may be used with end 1451 as needed or desired.

[0167] Figure 13 An exemplary configuration of an expandable inverted tip 1551 is depicted, which may include a braid having a proximal segment 1547, a middle segment 1545, and a distal segment 1543, whereby the braid of the tip 1551 may extend from a proximal end to a distal end. The tip 1551 may provide a more rounded inverted seam that may interact with a vessel wall during use.

[0168] Figure 14A An exemplary configuration of an expandable, invertible tip 1651 is depicted, which may include a braid having a proximal segment 1647, a middle segment 1645, and a distal segment 1643. Segment 1639 is proximal to segment 1647, and portions 1641 represent the transitions between each segment. Segment 1647 may be relatively rigid, segment 1645 may be relatively flexible, and segment 1643 may include a helical configuration relative to its filaments. Middle segment 1645, in turn, may be configured to distribute radial forces over a larger area during the inversion step of tip 1651. The relatively flexible middle segment 1645 in the middle portion may also reduce structural bending forces during inversion, particularly under the additional constraints of thin vessels, thereby reducing radial forces exerted by the structure and potential vascular trauma.

[0169] 14B to 14D Depicted is a view of the tip 1651 previously expanded and inverted into a funnel shape according to the present disclosure. Specifically, Figure 14C is a side plan view of the end 1651, and Figure 14D is the front plan of section 1651, and Figure 14B This is the rear plan view of section 1651. Figure 14D As shown, segment 1543 and its helical configuration can convert segment 1543 into a helix during inversion. Figure 14C It is also apparent in FIG. 16 that the inverted seam of the rounded lower corner segment 1645 can interact with the vessel wall during use. Figure 14BSegments 1647 and 1645 are shown forming the integrity of the braid and providing an inverted hinge at the transition point between segments 1645, 1643. The inverted hinge can be applied by heat setting the filament to have a larger diameter at the center than the proximal and distal ends to facilitate deformation, the film having sufficient resistance to expansion to maintain the enlarged diameter in a substantially tubular shape consistent with the proximal and distal segments in the collapsed configuration. This can be accomplished with non-shape memory materials by using an oversized braid and reducing the distal and proximal diameters (e.g., a backflow jacket material, adhesive, or by a restriction ring) by attaching means to the distal pull ring and proximal catheter body, respectively. Although not shown, it is contemplated that a coating or film as described herein can be used with tip 1651 as needed or desired.

[0170] Figures 15A to 16F Depicted is a view of an expandable invertible tip 1751 according to the present disclosure. Figure 15A 1752. Segment 1752 may include a proximal portion 1751 and a distal portion 1759, each having a braid pattern (e.g., the same pattern or a different pattern). A transition portion 1753 may be positioned between segment 1755 and segment 1752. In some examples of tip 1751, the braid may be looped around loop 1754 to allow the braid to rotate around loop 1754 during inversion, which may facilitate complete inversion of distal segment 1752. For illustrative purposes, Figure 15A Strictly represented as sections A, B, and C. It should be understood that the braided wire can be looped from A to C and back to A. However, segment 1751 is not limited to this, and the braided wire can also be looped from A to B and back to A. In other examples, the braided wire can be looped from A to B and then to A to C and back to A. In other examples, the braided wire can be looped from A to C, as well as any combination of these various braided wire looping configurations. In some examples, at least one braided wire of end 1751 can be twisted just proximal to loop 1754 to hold loop 1754 in place.

[0171] Go to Figure 15B , a close-up of tip 1751 is shown in an expanded, inverted, funnel-shaped configuration. Here, it can be seen that segment 1752 has inverted and expanded as ring 1754 has translated proximally, as shown in previous exemplary distal tips of the present disclosure. Figure 15C yes Figure 15B , but with the core shaft and / or dilator removed, leaving only the tip 1751 in an expanded, inverted funnel-shaped configuration.

[0172] Figure 16A yes Figure 15A A close up view of portion A of , showing the braided wire as previously described. Figure 16B yes Figure 15A A close up view of portion B of , showing the braid density or PPI variation as previously described. Figure 16C yes Figure 15A A close up view of portion C of the sectional view ... Figure 16D yes Figure 15A 1754. FIG. 1754 is a close-up cross-sectional view of section C along the centerline of FIG. 1754, wherein an exemplary expander 1770 is coupled to the ring 1754. As shown, the expander 1770 has circumferential ribs to grip the pull ring 1754. Figure 16E yes Figure 15A 1754 , where another exemplary expander 1770 is coupled to the ring 1754 , whereby the expander 1770 includes abutment features that fold distally to facilitate radial compression to squeeze through the ring 1754 after a predetermined force is reached. Figure 16F yes Figure 15A , showing a braided wire looped as previously described and coupled to loop 1754. The filaments in this example can extend from the proximal side to the distal side and can be looped back at the distal end. Loop 1754 can be passed through the looped end so that when inverted, the looped filaments rotate around loop 1754 to invert the outward-facing face to face radially inward, thereby forming a distally facing funnel, as shown.

[0173] Visibility during deployment of any of the catheter systems disclosed herein can be aided by the addition of alloying elements (such as palladium, platinum, gold, etc.), by applying radiopaque compounds, or by placing radiopaque markers on one or more of the catheters and devices. Suitable practices are frequently used in conjunction with other devices and implants and are well known in the art. For example, a radiopaque compound can be incorporated into a cover that can be incorporated into the distal tip, or one or more radiopaque markers can be added at, on, and / or near the distal end of the tip. In addition, one or more of the braided wires can include a DFT wire comprising a platinum core (for radiopacity) with a NiTi outer layer. Using such markers, the physician will be able to visually confirm that the opening has been fully inverted and expanded to the vessel wall.

[0174] The suction source used in the catheter systems of the present disclosure can be a manual syringe or a small-displacement vacuum pump, and suction is directed to the distal tip of any of the catheter systems disclosed herein. Effective suction can be achieved through the sealing action of the inverted funnel shape of the distal tip against the vessel wall, the inner wall of the outer catheter, and / or through the use of a flow restrictor / seal. However, in some cases, it is not possible to dislodge or completely retrieve a clot using suction alone with any catheter system to date. In this regard, it is contemplated that a thrombectomy device can be used with the catheter systems of the present disclosure and can be any of a number of commercially available products that can be supplied with or separately from the suction clot retrieval catheter. Using a thrombectomy device in conjunction with the expanded-opening catheter systems of the present disclosure has several benefits for increasing the likelihood of first-pass success. The thrombectomy device can support the lumen of the vessel during suction, making it less likely to collapse under negative pressure, and if the clot consists of a series of rigid and flexible portions that would otherwise fragment, the thrombectomy device will hold the clot together. The thrombectomy device also allows the user to clamp a clot that would otherwise not fully enter the lumen of the clot retrieval catheter between the catheter tip and the thrombectomy device. When the clot retrieval catheter, clot, and thrombectomy device are retracted as a single unit through the vasculature and outer catheter, the clamped clot is less likely to dislodge from the clot retrieval catheter.

[0175] Figure 17 The flowcharts each include method steps for performing a procedure using a system of the present disclosure. The method steps can be implemented by any of the exemplary systems, devices, and / or apparatus described herein or by methods known to those of ordinary skill in the art.

[0176] See also Figure 17 In method 1700 as outlined in FIG. 1 , step 1710 includes advancing any catheter of the present disclosure to a target site. Step 1720 includes retracting the distal tip of the catheter through a dilator at least partially within the lumen of the catheter, and preferably removing the dilator to maximize the suction flow rate and force on the clot retracted into the catheter, thereby causing the distal tip to expand and invert into a funnel shape.

[0177] In some examples of method 1700, the dilator can be withdrawn and suction can then be applied through the catheter, depending on how the user has deployed the flow restriction and / or seal, to stimulate the clot to enter the opening of the catheter. If suction alone is not sufficient to dislodge and capture the clot, or if additional gripping of the clot is required during the initial suction and removal, a microcatheter with a mechanical thrombectomy clot retrieval device can be advanced to the target. The mechanical thrombectomy device can then be deployed to capture the clot using any method generally known in the art. Suction can continue throughout this step or at intervals selected by the user to prevent blood reflux and maintain a tight grip on the clot. In some examples, aspirating and pulling the clot with a stent retriever may be optimal to increase the chances of first-pass success.

[0178] In some examples of method 1700, the captured clot and clot retrieval catheter may be withdrawn from the patient, or the clot retrieval catheter may be left in place to maintain access while the mechanical thrombectomy clot retrieval device is withdrawn from the patient along with the clot. If the clot is observed in the suction source and / or thrombectomy device and flow in the clot retrieval catheter is not blocked, this step may also involve carefully injecting contrast agent at low pressure through the system using known techniques to determine whether the vessel is patent. If the vessel is patent, the clot retrieval catheter may be removed. If obstruction persists, aspiration, thrombectomy, or a combination thereof may be repeated multiple times until the vessel is patent.

[0179] The present disclosure is not necessarily limited to the examples described, the configuration and details of which may vary. The terms "distal" and "proximal" are used throughout the foregoing description and refer to positions and directions relative to a treating physician or user. Similarly, "distal" or "distally" refers to a position away from the physician or in a direction away from the physician. Similarly, "proximal" or "proximal" refers to a position close to the physician or in a direction toward the physician. In addition, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" include plural references.

[0180] As used herein, the term "about" or "approximately" referring to any numerical value or range indicates a suitable dimensional tolerance that allows the component or collection of elements to achieve its intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of ±20% of the recited value, for example, "about 90%" can refer to a range of values ​​from 71% to 99%.

[0181] In describing the exemplary embodiments, terminology has been employed for the sake of clarity. It is intended that each term be given its broadest meaning as understood by those skilled in the art, and include all technical equivalents that operate in a similar manner to achieve similar purposes, without departing from the scope and spirit of the present disclosure. It should also be understood that reference to one or more steps of a method does not exclude the presence of additional method steps or intermediate method steps between those clearly identified steps. Some steps of the method may be performed in an order different from that described herein, without departing from the scope of the disclosed technology. Similarly, it should also be understood that some of the method steps may be omitted.

[0182] Reference to one or more components in a device or system does not exclude the presence of additional components or intermediate components between those explicitly identified. For the sake of clarity and conciseness, not all possible combinations are listed, and such modifications are generally obvious to those skilled in the art and are intended to fall within the scope of the appended claims.

Claims

1. A catheter system capable of being actuated to a deployed state, comprising: a catheter body, the catheter body comprising a lumen; a dilator positioned at least partially within the lumen, the distal end of the dilator being releasably connected to the distal tip of the catheter body, the dilator being retractable to expand and invert the distal tip and form a funnel shape in the deployed state, wherein the distal tip comprises: a proximal segment; and a distal segment extending from the proximal segment and being substantially flexible, a proximal end of the distal segment extending from the proximal segment, and the catheter system further comprising a pull ring adjacent to and / or connected to the distal end of the distal segment, and Wherein the proximal end of the distal tip and the pull ring each include mating surfaces configured to snap-lock together.

2. The system of claim 1 , wherein the midpoint of the distal segment in the collapsed state transitions to a distal-most atraumatic end of the funnel shape in the expanded state that is distal to the catheter body.

3. The system of claim 1, wherein the distal segment in the collapsed state is substantially tubular and in the expanded state comprises the funnel shape, the funnel shape forming an air cushion between the distal end and the pull ring.

4. The system of claim 1, the distal segment being divided into a proximal braid portion and a distal helical portion.

5. The system of claim 1 , wherein the expander comprises: proximal segment; a distal segment located distal to the proximal segment, the distal segment having a larger diameter than the proximal segment, the distal segment including a contact element extending radially outward from the distal segment and configured to contact and translate the pull ring proximally until aligned at or near the proximal end of the distal segment.

6. The system of claim 5, the contact element comprising an interference fit with the distal end of the distal tip of the catheter body.

7. The system of claim 5, the distal segment of the dilator having a maximum diameter at the contact element and gradually decreasing from the contact element to the distal end of the distal segment.

8. The system of claim 5, the distal section of the dilator having a maximum diameter at the contact element and tapering from the contact element to a junction between the proximal and distal sections.

9. The system of claim 5, the proximal section of the dilator being highly flexible or significantly more flexible than the distal section of the dilator.

10. The system of claim 9, further comprising: A substantially flexible segment extends distally of the more rigid distal segment, the substantially flexible segment being a short nose.

11. The system of claim 5, the proximal section of the dilator comprising a fiber reinforcement system to resist elongation.

12. The system of claim 1, wherein the proximal end of the distal tip and the pull ring lock together in the deployed state.

13. The system of claim 1, the distal tip being configured to initially expand to a substantially conical shape prior to inverting to form the funnel shape.

14. The system of claim 1 , wherein the distal tip comprises a braid comprising a proximal portion, a middle portion, and a distal portion, wherein the braid comprises filaments extending in a helical configuration from the proximal portion to the distal portion, wherein the distal portion comprises sufficient radial force to urge the proximal portion radially outward while being configured to accommodate various vessel sizes in an atraumatic manner.

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