Recovery catheter

Abstract

A catheter system for recovering substances or objects from a living body tube. The system includes a catheter having an outer tube covering a long trap, and the lumen of the outer tube forms a conduit for applying a suction force to the distal opening of the long trap when the long trap is deployed from the outer tube.

Description

Technical Field

[0001] Background The present invention relates to a catheter for retrieving a substance or an object from a living body tube, and a system and method for using the same. Embodiments of the present invention relate to a thrombus capture catheter configured to retrieve using suction, the thrombus capture catheter being configured to be able to compensate for collapse of the trap during suction.

Background Art

[0002] Vascular diseases caused by vascular occlusion are a major cause of mortality and morbidity in the United States.

[0003] Cerebral embolism is an occlusion in a blood vessel in the brain or an artery supplying blood to the brain. The occlusion can be caused by a blood clot, a fat globule, or an air pocket in the artery. Cerebral embolism causes embolic stroke, which accounted for one in six deaths due to vascular diseases in the United States in 2020.

[0004] Interventional procedures are routinely used to treat vascular diseases, and are particularly advantageous for treating vascular occlusions located in narrow and distant blood vessels such as vascular occlusions in the blood vessels in the brain.

[0005] Minimally invasive retrieval of cerebral emboli is usually performed using a retrieval catheter designed to capture and retrieve emboli using a mechanical trap and / or suction.

[0006] Such retrieval devices may be effective in retrieving small blood clots, but by using suction to retrieve large blood clots, the trap may collapse because the blood clot material blocks the trap opening. Due to such collapse, blood clot retrieval is often incomplete and the blood clot becomes fragmented.

[0007] To overcome the limitations of clot retrieval using such suction, the operator often disconnects the suction source (syringe or pump) to reverse the crush, reapplies suction to attempt to retrieve the clot, or completely withdraws the system from the vasculature to remove the trap and repeats the procedure. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Therefore, there is still room for improvement in the clot retrieval system, particularly in the complete retrieval ability of the system that utilizes suction. MEANS FOR SOLVING THE PROBLEMS

[0009] SUMMARY According to one aspect of the present invention, there is provided a system for retrieving a substance or an object from a living tube, including a catheter having an outer tube covering a long trap, wherein the lumen of the outer tube forms a conduit for applying a suction force to the distal opening of the long trap when the long trap is deployed from the outer tube.

[0010] According to an embodiment of the present invention, when deployed from the outer tube, the proximal portion of the long trap forms a fluid-tight seal with the inner wall of the outer tube.

[0011] According to an embodiment of the present invention, the proximal portion is externally coated with a polymer capable of maintaining a fluid-tight seal.

[0012] According to an embodiment of the present invention, the long trap is formed from a braided structure that is radially expandable or extensible when deployed.

[0013] According to an embodiment of the present invention, the braided structure is internally coated with a polymer.

[0014] According to an embodiment of the present invention, the distal portion of the outer tube is more flexible than its proximal portion.

[0015] According to an embodiment of the present invention, the outer tube includes a wire braid in the proximal portion.

[0016] According to an embodiment of the present invention, the outer tube includes a wire helix in the distal portion.

[0017] According to an embodiment of the present invention, when radially expanded, the coated braided structure is conical with a chamfered distal end.

[0018] According to an embodiment of the present invention, the system further includes a probe that can be positioned within the elongated trap, and the probe is for identifying the presence of substances or objects within the elongated trap.

[0019] According to an embodiment of the present invention, the probe includes a radiopaque marker.

[0020] According to an embodiment of the present invention, the system further includes a pressure probe.

[0021] According to an embodiment of the present invention, the pressure probe is a strain sensor.

[0022] According to an embodiment of the present invention, the system further includes a rod or wire for moving the braided structure relative to the outer tube.

[0023] According to an embodiment of the present invention, the rod or wire is attached to the wall of the outer tube or positioned within a channel formed within the wall.

[0024] According to an embodiment of the present invention, the elongated trap includes a chamfered opening at its proximal end.

[0025] According to an embodiment of the present invention, the wire or rod is attached to the side of the chamfered opening.

[0026] According to an embodiment of the present invention, the system further includes a suction source fluidly connected to the outer tube.

[0027] According to an embodiment of the present invention, the system further includes an element for restricting the bending radius of the braided structure along its longitudinal axis.

[0028] According to an embodiment of the present invention, this element is a support column that interconnects the braided structure and the wire or rod.

[0029] According to an embodiment of the present invention, this element is designed to limit the bending radius of the braided structure to 1 mm or more.

[0030] According to an embodiment of the present invention, the system further includes a suction source connected to the inner cavity of the outer tube, a pressure sensor for detecting the pressure in the inner cavity or the elongated trap, and a control unit for controlling the pressure of the suction source.

[0031] According to an embodiment of the present invention, when the sensor detects an increase in pressure, the control unit can automatically reduce the pressure applied to the inner cavity by the suction source.

[0032] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described below. In case of conflict, the present patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0033] Brief Description of the Drawings In this specification, the present invention will be described by way of example only with reference to the accompanying drawings. Here, referring specifically and in detail to the drawings, it is emphasized that the details shown are for purposes of illustration only, and are presented merely for the purpose of providing an exemplary consideration of the preferred embodiments of the present invention, and for providing what is considered to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt has been made to show the structural details of the present invention in more detail than is necessary for a basic understanding of the present invention, and the description using the drawings will make it clear to those skilled in the art how some forms of the present invention can actually be embodied.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0035] DETAILED DESCRIPTION The present invention relates to a catheter, a system, and a method that can be used to retrieve substances / objects such as blood clots and plugs from a living body tube such as a blood vessel in the brain.

[0036] The principles and operations of the present invention can be better understood with reference to the drawings and the accompanying description.

[0037] Before detailing at least one embodiment of the present invention, it should be understood that the present invention is not limited in detail to what is shown in the following description or illustrated by the examples in its application. The present invention is capable of other embodiments or of being practiced or carried out in various ways. It should also be understood that the terminology and phraseology employed herein are for the purpose of description and should not be regarded as limiting.

[0038] In the art, catheters for capturing and extracting thrombus substances are well known. Such catheters use suction force to entrap and capture embolic substances and remove them from the body.

[0039] One problem that is often faced with such devices is that the trap collapses due to blockage of the distal opening of the trap while it is being aspirated. In such situations, the physician often has to withdraw the system, unplug it, and repeat the procedure.

[0040] During the implementation of the present invention, the inventors experimented with several catheter designs to minimize or compensate for such collapses.

[0041] Accordingly, according to one aspect of the present invention, a catheter system for retrieving a substance or an object from a body conduit is provided.

[0042] As used herein, the term "substance" refers to biological substances such as those characterizing thrombi / emboli, and the term "object" refers to implants such as stents, stent grafts, etc.

[0043] The present system can be used to access and treat any body conduit, examples of which include conduits of the circulatory system (e.g., arteries, veins, lymphatic vessels), conduits of the urinary tract (e.g., urethra, ureter), and conduits of the lymphatic system. The present catheter system is particularly suitable for use in cerebrovascular (venous - arterial) vessels.

[0044] The system of the present invention includes a catheter, and the catheter is attached to an elongate trap configured to be deployed from the lumen of the catheter (a trap that can form a tubular or conical sleeve when deployed). When deployed from the catheter lumen (by advancing the trap from the catheter and / or pulling the catheter to expose the trap), the shape of the elongate trap is determined by the diameter of the tube. When the trap is expanded within a tube smaller than the outer diameter of the catheter, the trap takes on a tubular shape. When the trap is expanded within a tube larger than the outer diameter of the catheter, the trap takes on a conical shape with a diameter that tapers from the distal end to the proximal end. The elongate trap can be a coated braided structure that is self-expanding, in which case at least a portion of it self-expands to a final diameter limited by the diameter of the tube (and to a diameter limited by the braided structure and the deployment range from the catheter sheath).

[0045] The elongate trap includes a lumen that is open at both the distal and proximal ends. The distal end opening can be circular in shape and perpendicular to the longitudinal axis of the catheter, or can be elliptical in shape and inclined / angled (oblique) with respect to the longitudinal axis of the catheter (also referred to herein as a "shovel configuration"). The proximal opening can be circular in shape and perpendicular to the longitudinal axis of the catheter, or can be elliptical in shape and inclined / angled (oblique) with respect to the longitudinal axis of the catheter.

[0046] When collapsed within the catheter, the elongate trap is a thin cylindrical body having a lumen with a diameter of 0.9 to 4 mm (sufficient to pass a guide wire and / or a microcatheter through and sufficient for aspiration of substances).

[0047] According to one embodiment of the present invention, the elongate trap can be manufactured from metal (e.g., stainless steel or nitinol) or polymer (e.g., PTFE) wires braided in alternating helical and reverse helical directions. The braid can be (fully or partially) coated with a polymer such as TPU, silicone, or polyurethane so that a vacuum can be applied to the lumen (internal volume) of the elongate trap. Such a coating can be internal or external. The internal coating is advantageous in that the uncoated outer surface does not completely seal against the blood vessel wall and does not completely block the flow. In addition, the internal coating results in a smaller outer shape of the packing because the folds of the coating are tightly packed inside the braided structure.

[0048] The diameter of the wire can be from 0.02 to 0.25 mm, and the braiding angle between the wires can range from 50 to 140 degrees. The elongate trap can be manufactured by winding the wires in an alternating helical pattern using a mandrel of a suitable size. For example, one wire can be looped, and the tail of the loop can be wound around the mandrel in a helical pattern to form a cross pattern (1×1 pattern) for all the wires along the length of the mandrel or a cross pattern (2×1 pattern) for every two wires. A braided structure can be formed using several (12 to 64) wires. An example of such a braid is provided in International Publication No. WO 2019 / 064306. The elongate trap can include a wire loop at its distal end (surrounding the opening of the expanded elongate trap). The wire loop provides axial support and forms leaflets that reduce the compression of the braid when the elongate trap contacts a blood clot (thereby minimizing the accordion effect that can occur when the braided structure is pushed against the blood clot). The wire loop also forms a soft tip that minimizes trauma to the tube during deployment.

[0049] The parameters and dimensions of the catheter and the elongate trap are determined by the application and the type of the tube. When used in the intracranial artery in ischemic stroke, the size of the target artery can vary from 1.5 to 4.5 mm. The diameter of the elongate trap must be at least slightly larger than the diameter of the blood vessel in order to block the blood flow, and thus ranges from 2 to 7 mm. The length of the elongate trap is long enough to support receiving a long blood clot within the lumen, but can be made short enough so that the elongate trap can be deployed by being pushed out from the outer tube of the catheter or pulled in from the sheath.

[0050] The catheter of the present system is used to deliver and deploy the trap. According to one embodiment of the present invention, the catheter system includes a single (outer) tube (forming the catheter body / shaft) and an elongate trap. The elongate trap is positioned within the lumen of the outer tube and is pushed out to be deployed via a wire / rod attached to the proximal end of the elongate trap. The wire is attached to the proximal end offset from the opening. When the proximal end is chamfered, the wire is attached to the most proximal tip of the chamfered portion. The proximal portion of the elongate trap includes an outer coating (e.g., PEBAX, Pellethane, Carbothane, nylon) selected to form a seal with the inner wall of the outer tube and prevent the proximal opening from collapsing when a suction force is applied through the lumen of the outer tube. As shown in Figure 3D, the distal end of the coating can be inclined to minimize the friction with the outer tube when the elongate trap is inserted into and removed from the outer tube.

[0051] The catheter system may also include a suction source (e.g., a syringe, a peristaltic pump) capable of applying a suction force to the lumen (internal volume) of the elongate trap through the lumen of the outer tube. Thus, the outer tube forming the catheter body functions both to cover the elongate trap and to provide a suction force to its lumen. Such a configuration is advantageous in that it provides a relatively large-diameter lumen through which a suction force can be applied to the relatively small proximal opening of the elongate trap.

[0052] When the long - shaped trap is (at least partially) deployed from the outer tube, the inner cavity of the outer tube forms a seal with the outer wall of the long - shaped trap. To strengthen such a seal, the proximal portion of the long - shaped trap includes a coating that forms a seal with the inner wall of the outer tube.

[0053] By applying a suction force through the inner cavity of the outer tube, an equal suction force is generated at the distal opening of the long - shaped trap when it is deployed. By adopting the outer tube as the suction conduit, it is ensured that any collapse of the long - shaped trap during suction does not break the seal between the inner cavity of the outer tube and the outer (coated) wall of the long - shaped trap. When this seal is broken, the suction force is directed at least partially into the space between the outer wall of the long - shaped trap and the tube wall, i.e., the space filled with biological fluid (e.g., blood). As a result, the suction force into the trap lumen decreases, fluid is suctioned from the space between the trap and the tube wall, and thus a pressure equalization occurs that leads to the re - expansion of the long - shaped trap. Thereby, the trap can be resealed against the outer tube lumen, and a full recovery of the suction into the trap lumen becomes possible. Due to such automatic (repeatable several times) “pulsations”, the substances remaining at the distal opening of the trap can be advanced proximally.

[0054] While experimenting with several trap designs, the inventors have identified trap parameters that allow the collapse - expansion cycle described above. For example, the trap can have a conical shape when expanded, the diameter ratio of the distal end to the proximal end is 2.3, the length of the trap is three times the diameter of the distal end, the thickness of the coating is 25 μm or less, and the radial collapse pressure is about 7 - 14 PSI.

[0055] The system may further include at least one of a pressure sensor (positioned within the catheter lumen, within the lumen wall, or in the pump), an element for limiting the bending radius of the trap to minimize kinking of the trap when advancing through tortuous anatomical structures, a radiopaque marker, and a plug / object detection probe (positionable within the trap). These optional and individually applicable features are further described below with reference to the figures.

[0056] Referring now to the drawings, FIGS. 1 - 4C illustrate a catheter system of the present invention, hereinafter referred to as system 10.

[0057] System 10 includes a catheter body / shaft 12 that forms an outer tube 14 (FIG. 1C) surrounding a lumen 16. A long trap 18, used to capture and / or retrieve substances or objects (into lumen 19) from a body tube (e.g., an artery), is positionable within lumen 19 and deployable therefrom for retrieval. The trap 18 shown in the figures is a coated braided structure 20 (FIG. 1C), although alternative trap configurations such as a polymer tube, an umbrella structure, etc. are contemplated herein.

[0058] Lumens 16 and 19 can be used to position system 10 on a guidewire, or alternatively, the wall of lumen 16 can include a dedicated guidewire lumen. System 10 can be configured for standard over-the-wire or rapid exchange delivery. In the latter configuration, the catheter body 12 can include a guidewire opening along its length.

[0059] The coated braided structure 20 can be constructed using several wires with different degrees of rigidity. The braid forms a dense network of thin wires that serves as a substantial support for the encompassing polymer coating. By integrating thick wires, important regions such as the distal and proximal openings are reinforced, and the overall structure is strengthened against suction forces. The ratio of the bending rigidity of the thin wires to the thick wires can be in the range of 1:2 to 1:3.

[0060] The coated braided structure 20 can include a combination of 24 50-μm diameter Nitinol (NiTi) wires with 4 64-μm diameter NiTi wires or a combination of 16 50-μm diameter NiTi wires with 8 64-μm diameter NiTi wires. It is a DFT wire having a 1×1 braided pattern at an angle of 125°. The braid is internally coated with polyurethane.

[0061] The lumen 19 of the trap 18 includes a distal opening and a proximal opening (22 and 24, respectively). When the braided structure 20 is coated, the proximal opening 24 can be surrounded by a radiopaque marker band 57, which can be fixed by crimping to the proximal end of the trap 18 and the distal end of the wire / rod 26 used for deployment of the trap 18 (to be further described later). In addition, the proximal portion of the braided elongate trap 18 can also include an outer coating 25 of a polymer such as PEBAX, Pellethane, TPU, or nylon (FIGS. 1C and 3D), thereby preventing the proximal portion and the opening 24 from collapsing during the application of suction and also strengthening the seal between the proximal portion and the inner wall of the outer tube 14.

[0062] A catheter shaft 12 of suitable length, diameter, and flexibility for the intended treatment site is selected. The distal flexibility and the proximal flexibility are used for the implementation of tracking. A jacket of a soft material (PEBAX, polyurethane, or polyamide composite materials of various durometer ratings) is braided at the proximal portion and coiled at the distal portion to achieve the distal flexibility (for advancing / positioning the trap 18 within tortuous anatomical structures) and the proximal stiffness (for pushability).

[0063] Figure 3A shows a flexible tube for pushing and pulling a trap inside an outer tube. Figure 3B shows the interface between the flexible tube and the trap connection. The distal end of the flexible tube can be made from a thin-walled metal hypo-tube having horizontal notches that allow for flexible sections, and each notch section can have a different shape for different flexible sections (more flexible distally and pushable proximally). The distal end of the flexible tube also has notches (horizontal and vertical) for connecting the trap to the flexible tube with various mechanical connections (e.g., adhesive or stitching) to form a strong connection that still maintains flexibility and kink resistance.

[0064] The catheter shaft 12 can be 130 - 150 cm in length and 0.2 - 0.8 mm in outer diameter. The inner lumen 16 can be 0.9 - 2.0 mm in diameter, and the elongated trap can be 0.9 - 2.0 mm in diameter when collapsed within the inner lumen 16 and 2.0 - 7.0 mm in diameter when deployed from the inner lumen 16. The trap 18 can be 10 - 30 mm in length.

[0065] The system 10 can also include, for example, a pull wire for closing the trap 18 following the capture of a thrombus.

[0066] The pull wire extends from the proximal end through the lumen or wall of the catheter body / shaft 12 and through the lumen of the trap 18 (optionally in a helical pattern) and is attached to the distal end of the trap 18 (e.g., to a wire loop forming the distal end of the trap with a coated braided structure 20).

[0067] Closure can be by constriction (e.g., purse-string suture) or by deflection by pulling an extended portion (shovel tip) of the distal end towards the base of the shovel (in the configuration of the shovel). Alternatively, the shovel tip can be tilted downward by 10 - 30 degrees and the closure wire pulled and lifted, thereby changing the height of the shovel to detach the thrombus from the vessel wall.

[0068] The catheter body / shaft 12 of the system 10 is attached to the handle 40, which includes a mechanism for deploying the trap 18 and optionally a closure wire for closing the distal end of the trap 18, along with a port 42 for attaching the syringe 44 (I in FIGS. 1A and 1B) or the pump 46 and the control unit 48 (II in FIGS. 1A and 1B).

[0069] The syringe 44 or the pump 46 is fluidly connected to the lumen 16 and can apply a suction pressure of -1 to -15 psi at a flow rate of 400 to 600 ml / min to the lumen 16 (and thus the lumen 19 of the deployed trap 18).

[0070] The syringe 44 is used manually by the operator, while the pump 46 (and the attached / built-in control unit 48) is motor-driven (e.g., a peristaltic pump). The pump 46 can be operated in an open-loop configuration or a closed-loop configuration. In the latter case, the control unit 48 can be connected to a pressure sensor positioned within the lumen 16, the wall of the lumen 16, the pump 46, or the port 42. The control unit 48 can include software for adjusting the suction force applied by the pump 46 according to the suction pressure measurement from the pressure sensor.

[0071] For example, due to clogging of the trap 18 in the suction state, the pressure detected by the pressure sensor can increase, and this increase in pressure can lead to the collapse of the trap 18. To avoid or correct such a collapse (e.g., in a configuration of the system 10 that does not automatically compensate for such a collapse via the formation of an alternative suction path), the software of the control unit 46 automatically reduces the suction pressure from the pump 44 to re-expand the trap 18. When re-expansion (indicated by the pressure sensor) occurs, the software can increase the suction pressure applied to the blood clot from the pump 44. Such suction "pulses" can improve the ability of the system to collect blood clots.

[0072] FIG. 4A shows two optional positions of the pressure sensor 43. The pressure sensor 34 can be, for example, a strain gauge element embedded or attached to the wall of the catheter body 12, or a piezoresistive or differential pressure sensor positioned within the port 42 or the pump 44.

[0073] The handle 40 also includes a mechanism for deploying the trap 18 (to the state shown in FIG. 1B). This mechanism can pull back the catheter body / shaft 12 via a wire / rod or push the trap 18 forward. The rod can be hollow and can include sidewall notches for flexibility.

[0074] For example, the deployment of the trap 18 can be performed using a wire / rod 26 attached to the proximal end of the trap 18 (FIG. 1C). By using the wire / rod 26 and pushing the wire / rod 26 forward, the trap 18 can be advanced out of the lumen 16. The wire / rod 26 is connected to the trap 18 at a position around the proximal opening 24 (a side position, a position off-center). When the proximal opening 24 is chamfered, the wire / rod 26 is attached, for example, at the nearest point of the chamfered portion via crimping 57 or welding (FIGS. 1C, 3D).

[0075] The proximal end of the wire / rod 26 is attached to the handle 40 of the system 10. The handle 40 includes a mechanism for pushing / pulling the wire / rod 26 (and / or pulling / pushing the catheter body 12). Such a mechanism can be a rotary wheel, a slider button, or a ratchet trigger. This mechanism can provide the user with a visual or audible indication of deployment and the degree of deployment, and prevent uncontrolled movement of the wire / rod due to internal friction of the system.

[0076] System 10 may further include a probe 50 for detecting the presence of a substance / object in or at trap 18. FIGS. 2D and 4C show one configuration of such a probe 50 attached to wire 54. In such a configuration, detection depends on visualization of the radiopaque movement of the probe position in fluoroscopy. In the case of a flexible wire with a marker band attached to the distal end, when the probe encounters a substance or object, the flexible wire deflects the probe proximally.

[0077] Since system 10 can be used in tortuous tubes (e.g., cerebral blood vessels), by positioning trap 18 within such a tube to collect a blood clot, when the radius of curvature of the tube is relatively small (e.g., less than 1 mm), trap 18 may collapse or kink. In such cases, trap 18 may include an element 52 for restricting / suppressing its bending radius. An example of such an element 52 is shown in FIG. 4B. Element 52 can be a bent wire passing through trap 18, the bent wire having its end fixed proximally of trap 18 and its distal end being free. Element 52 has a bending modulus of elasticity greater than that of trap 18, which restricts / suppresses the bending radius of trap 18.

[0078] FIGS. 2A - 2D show the deployment of trap 18 from catheter body 12 and blood clot collection.

[0079] System 10 is delivered over a guide wire from an access site (e.g., transfemoral artery, transradial artery) to blood clot 60 (FIG. 2A) under fluoroscopic imaging using standard over - the - wire or rapid - exchange delivery techniques. The guidance of system 10 can be monitored using radiopaque markers 55 (FIG. 3C) attached to trap 18 and / or catheter body 12.

[0080] Trap 18 is deployed immediately adjacent to blood clot 60, and suction is applied through lumen 16 to lumen 19. If blood clot 60 occludes the distal opening 22 of trap 18 (as shown in FIG. 2B), due to the radial elastic properties of trap 18, trap 18 will collapse under the suction force (FIG. 2C), and an alternative suction path (S in FIG. 2D) will be formed between the outer wall 62 of trap 18 and the inner wall 64 of catheter body 12. By applying suction to the space formed between trap 18 and the wall of the tube (not shown), the pressure will equalize between the lumen 19 of trap 18 and the surrounding space, and trap 18 will re-expand. As a result, the suction path to lumen 19 will be re-formed, and the suction force will be directed towards blood clot 60 again. Such an automatic compensation mechanism effectively pulsates blood clot 60 into trap 18 (in a peristaltic-like action), enabling complete entrapment of blood clot 60.

[0081] When retrieved, trap 18 containing blood clot 60 can be retracted into catheter body 12, and the entire system can be removed from the body. Alternatively, blood clot 60 can be suctioned from lumen 16 into syringe 42 or pump 44 and expelled outside the body without removing system 10.

[0082] As used herein, the term "about" refers to ±10%.

[0083] Additional objects, advantages, and novel features of the present invention will become apparent to those skilled in the art upon examination of the following examples, which are not intended to be limiting.

Examples

[0084] Example Reference is now made to the following examples, which, together with the above description, illustrate the invention without limitation.

[0085] Prototype Test A prototype constructed according to one embodiment of the present invention was bench-tested for occlusion probability and suction effect.

[0086] The prototype includes a single-lumen catheter body and a self-expanding trap constructed of a wire braid coated with polyurethane (Figs. 5A and 5B). A deployment rod was connected eccentrically to the proximal end of the trap and used to deploy the trap from the catheter lumen. The lumen of the catheter body had its inner wall sealed against the outer surface of the trap and served as a suction lumen. When the trap collapsed during suction, a secondary suction path was formed between the inner wall of the lumen and the outer surface of the trap, thereby equalizing the pressure and restoring the shape of the trap. This pressure equalization resulted in a pulsatile effect, thereby facilitating the suction of blood clots occluding the distal opening of the trap (peristaltic-like effect).

[0087] The trap was beveled and had open ends. Fig. 5A shows the expanded trap with the beveled distal end. Fig. 5B shows the beveled proximal end with the rod connected (crimped) to the most proximal end of the beveled opening (the attachment point projects approximately 2 mm proximally).

[0088] Materials and Methods A silicone replica model of the Circle of Willis (manufactured by New England Center for Stroke Research, University of Massachusetts) was connected to a flow loop driven by a peristaltic pump delivering a flow rate of 140 ml / min. Soft, elastic lamb blood clots were used to occlude the MCA trunk.

[0089] To mimic peripheral resistance, the MCA trunk was constricted distal to the thrombus. The system was run at a flow rate and pressure of 100 mmHg. A 6Fr introducer catheter sheath was placed proximal to the occlusion in the ICA, and the prototype was advanced through it proximal to the thrombus. The prototype was partially deployed, and the self-expanding trap was expanded to the MCA diameter. Suction was applied via a Vac-Lok 30cc syringe connected to the catheter tube body.

[0090] Results Induction and exposure in the clot were successful, and the clot was aspirated in one pass. The clot was broken down into two fragments. The first fragment occluded the trap but was completely aspirated by the pulsations resulting from pressure equalization following collapse of the trap. After the first fragment entered the trap, the second fragment followed. The clot disintegrated, but no distal embolization occurred because the trap sealed the artery.

[0091] Conclusion In prior art catheter designs, multiple passes are often required to retrieve clots that occlude and collapse the catheter trap. This prototype catheter demonstrated a significant improvement in retrieving clots that can occlude and collapse the trap by completely aspirating soft clots into the syringe in a single pass.

[0092] It is understood that specific features of the invention described in connection with separate embodiments may be provided in combination in a single embodiment for clarity. Conversely, various features of the invention described in connection with a single embodiment for brevity may be provided separately or in any suitable subcombination.

[0093] Although the invention has been described in connection with its specific embodiments, it will be apparent to those skilled in the art that many alternative, modification, and variation are possible. Therefore, the invention is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims. All publications, patents, and patent applications mentioned herein are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. Additionally, any reference citation or identification in this application should not be construed as an admission that such reference is available as prior art to the present invention.

Claims

1. A device for removing blockages from a subject's blood vessels, A flexible catheter, The proximal part and, A distal portion configured for transluminal advancement into the blood vessel, comprising a distal portion having a catheter rim, The lumen extends from the proximal portion to the catheter rim, A flexible catheter having, It's a trap, Formed from a set of braided wires covered with a covering, The distal end of the trap has a distal opening, and the distal opening is A first shovel formed from the set of wires, comprising a first shovel protruding distally, An opposing shovel defined by the set of wires, which is located on the opposite side of the first shovel and protrudes distally, Define the area, The proximal end of the trap is chamfered and defines a proximal opening that defines the trap rim, The distal opening is biased to be in a more expanded state than the proximal opening and the catheter rim. A trap that is compressible within the lumen, with the distal opening being narrower than when it is in the expanded state, A device including a device.

2. The apparatus according to claim 1, wherein the first shovel protrudes distally beyond the opposing shovel.

3. The apparatus according to any one of claims 1 to 2, wherein the first shovel is longer than the opposing shovel.

4. The apparatus according to claim 1, wherein each set of wires has a different rigidity.

5. The apparatus according to claim 1, wherein the distal opening is a non-circular ellipse located obliquely to the longitudinal axis of the trap, and the first shovel and the opposing shovel spread out away from the ellipse.

6. The distal opening is chamfered, the apparatus according to claim 1.

7. The aforementioned set of wires is A first subset of wires defining the first thickness, A second subset of wires defining a second thickness smaller than the first thickness, The apparatus according to claim 1, which defines the following.

8. The apparatus according to claim 7, wherein a first subset of the wires extends around the distal end of the trap and defines the distal opening.

9. The apparatus according to claim 1, wherein the first shovel extends distal to the distal opening in a shovel-like manner.

10. The apparatus according to claim 9, wherein the opposing shovel extends distal to the distal opening in a shovel-like manner.

11. The apparatus according to claim 1, wherein the first shovel and the opposing shovel are in contact at exactly two joints.

12. The apparatus according to claim 1, wherein the first shovel is externally tangent to only a portion of the distal opening.

13. The apparatus according to claim 1, wherein the opposing shovel is externally tangent to only a portion of the distal opening.

14. The apparatus according to claim 1, wherein the first shovel and the opposing shovel spread outward so as to be separated from each other and away from the longitudinal axis of the trap.

15. The apparatus according to claim 1, wherein the first shovel and the opposing shovel are in contact at a first position and define a first node, and are in contact at a second position and define a second node, and each of the first node and the second node is proximal to the opposing shovel.

16. The proximal end is chamfered, the apparatus according to claim 1.

17. The apparatus according to claim 1, wherein the first shovel is defined by a wire loop that extends distally and partially circumsects the distal opening.

18. The apparatus according to claim 17, wherein the wire loop extending distally is angled outward to form the first shovel.

19. The apparatus according to claim 1, further comprising a wire attached to the proximal end of the trap and extending proximal through the lumen of the catheter.

20. The aforementioned proximal end is chamfered, The apparatus according to claim 19, wherein the wire is attached to the nearest tip of the chamfered portion.

21. The apparatus according to claim 19, further comprising a handle in the proximal portion of the catheter, the handle comprising an actuator, the actuator being operably connected to a flexible wire such that manual operation of the actuator causes the apparatus to progressively transition between (i) a delivery state in which the trap is in the compressed state within the catheter and (ii) an unfolded state in which the trap is in the expanded state and the distal opening is exposed from the distal portion of the catheter.

22. The apparatus according to claim 21, wherein the actuator is a ratchet mechanism.

23. The apparatus according to claim 21, wherein the actuator is a slider, and the actuator is operable by sliding the slider.

24. The apparatus according to claim 21, wherein the actuator is a wheel, and the actuator is operable by rotating the wheel.

25. The apparatus according to claim 21, wherein the handle is configured to provide a visual indication of the deployment of the trap.

26. The apparatus according to claim 21, wherein the handle is configured to provide an audible indication of the deployment of the trap.

27. The apparatus according to claim 21, wherein the handle is configured to prevent uncontrolled movement of the wire within the lumen.

28. The apparatus according to claim 21, wherein the proximal portion of the catheter is attached to the handle.

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