Improved catheter and devices and systems incorporating same

Abstract

A catheter is provided that includes a sheath defining a lumen and including at least some along a length of the sheath a helical support enclosed by the sheath material, the catheter including at least a proximal portion and a distal portion having a distal end, the distal portion having a corrugated outer surface over at least some of a length of the distal portion, wherein the helical support is enclosed in the corrugations of the outer surface in this portion; the sheath including an inner liner defining the lumen, and the inner liner including a ePTFE tubular layer in the distal portion and a PTFE tubular layer in the proximal portion, and a transition section in which the inner liner tubular layers contact without overlapping, or contact through a lap joint in which the tubular layers are concentric.

Description

[0001] This application is a divisional application of the invention patent application filed on December 14, 2018, with application number 201880081023.6 and entitled "Improved catheter and device and system for incorporating such catheter". Technical Field

[0002] This application relates to catheters and devices and systems for incorporating such catheters, as well as methods of using them. One example is a flexible catheter for endovascular surgery. Background Technology

[0003] Most endovascular procedures require the use of flexible catheters, such as for contrast agent injection, delivery of implantable devices, vascular surgery, or aspiration. Due to the tortuous nature of the vascular system, it is important that the catheter possesses sufficient flexibility to pass through vessels without excessive force. However, a trade-off is typically struck between catheter diameter, traceability, flexibility, and torsion resistance. Increasing the catheter diameter tends to increase catheter stiffness, thereby reducing traceability and potentially dangerously increasing vascular shear forces. Increased flexibility tends to increase the catheter's tendency to torsion as it is pushed through the vascular system, limiting the catheter to vessels with gentle curves. Generally, reducing wall thickness increases flexibility and allows access to more tortuous vessels, requiring a trade-off between bending stiffness and torsion resistance.

[0004] The present invention aims to provide a catheter with improved properties of bending stiffness and flexibility, thereby allowing use in difficult locations, such as in locations with significant bends and small dimensions in a patient's blood vessels. Summary of the Invention

[0005] The catheter has a sheath defining a chamber and a helical support. The catheter has a proximal portion and a distal portion, the distal portion having a corrugated outer surface over at least some of its length. The transition portion has a greater bending stiffness than the distal portion but less than the proximal portion. The transition portion provides an optimal transition in bending stiffness through features of the sheath, including the geometry of the sheath corrugations or overlapping tubular layers. In some examples, the distal end of the distal portion may have an extension of padding material folded up to provide a particularly soft tip. In other examples, the padding terminates before the distal tip. This catheter is particularly suitable for suction devices with a flow restrictor and the distal portion of the flow restrictor. The suction system can use the catheter with a pump that dynamically applies negative or positive pressure to optimally aspirate clots.

[0006] In one aspect, we describe a catheter comprising a sheath defining a chamber and including at least some helical supports in the sheath material along the length of the sheath. The catheter includes at least a proximal portion and a distal portion, the distal portion having a corrugated outer surface over the length of at least some of the distal portion. The catheter preferably includes a transition portion between the proximal and distal portions, the transition portion having a bending stiffness greater than that of the distal portion and less than that of the proximal portion. The transition portion preferably has a corrugated outer surface, wherein at least some of the corrugations on the corrugated outer surface have a smaller depth and / or width than the corrugations on the surface of the distal portion.

[0007] Other aspects of the catheter are presented below.

[0008] We also describe a method of manufacturing a conduit according to any embodiment, wherein a sheath is formed in at least some regions by: positioning a membrane over a helical structure, applying heat to allow the membrane to recirculate, causing the membrane to form around the helical structure, winding a tensioned binding wire around the outside of the membrane to force the membrane material into the grooves between each loop of the helical structure, heat-setting the membrane to fix the corrugations in place, and unwinding the tensioned binding wire, leaving the corrugations.

[0009] The sheath may comprise a fluoropolymer, which may bond to each other and / or to other polymers at the bonding interface. The interface may be chemically treated using an etching solution. The etched fluoropolymer may be coated with a thin layer of urethane (e.g., Chornoflex), which flows and functions when heat is applied to bond the fluoropolymer to a second etched fluoropolymer layer or different polymer layers.

[0010] On one hand, the method includes: providing a helical support within a polymer sheath, which is bonded to a liner to form a base assembly; placing an outer liner, not bonded to the polymer sheath, over a sheathed coil; helically winding a binding wire around the outside of the outer liner under tension, thereby applying a corrugated geometry; heating to reflow or anneal the material to set the material into a corrugated geometry; cooling the assembly; removing the binding wire; and stripping the outer liner.

[0011] We also describe a suction device comprising a conduit and a flow restrictor according to any of the embodiments described herein, wherein a distal portion is distal to the flow restrictor. The conduit may include a transition portion between the proximal and distal portions, the transition portion having a bending stiffness greater than that of the distal portion and less than that of the proximal portion, and at least a portion of the transition portion extending distally to the flow restrictor.

[0012] A flow restrictor may include a balloon, which is configured to inflate to block blood flow before the clot is aspirated into the distal portion of the catheter. Alternatively, a flow restrictor may be used to block blood flow before precisely delivering an embolic agent to an area of ​​the vascular system, tumor, or organ.

[0013] In one case, the length of the distal portion is adapted to reach a specific anatomical location, such as the distal internal carotid artery, the terminal portion of the internal carotid artery, the proximal MI, the distal MI, the proximal M2, the distal M2, the basal or vertebral vessels, wherein the flow restrictor is maintained in or near the C1 segment of the ICA.

[0014] The various aspects of the suction device are described below.

[0015] We also describe a method of using the aspiration device according to any embodiment, the method comprising the steps of: deploying the aspiration device in a patient's blood vessel; directing the distal portion to the clot in the blood vessel; using a flow restrictor to stop blood flow; and applying a vacuum to the catheter to aspirate the clot to the distal portion.

[0016] In one example, the method includes:

[0017] Angiography is performed to determine the location of the occlusion and the distance between the petrous or cavernous segment of the carotid artery and the occlusion.

[0018] Select a catheter whose distal portion is of suitable length to reach the clot causing the occlusion, while ensuring that the flow restrictor is not positioned outside the carotid artery.

[0019] Guide the distal portion of the catheter to the clot.

[0020] Activate the flow limiter to impede flow and minimize alternative flow paths that could reduce pumping efficiency.

[0021] A vacuum is applied to the chamber of the catheter to aspirate the clot.

[0022] If a clot is collected, another angiography will be performed via a balloon guiding catheter or diagnostic catheter, and

[0023] Remove the catheter.

[0024] We also describe an aspiration system comprising a catheter according to any embodiment, a pump connected to a proximal portion of the catheter, and a controller configured to vary the aspiration pressure during clot aspiration. The system may include a chamber pressure sensor, and the controller is configured to vary the aspiration pressure based on sensed pressure within the catheter chamber.

[0025] The system may include a chamber fluid flow sensor, and the controller is configured to change the suction pressure based on the sensed fluid displacement in the chamber.

[0026] The controller can be configured to improve aspiration efficiency by preventing catheter blockage, and / or to promote the softening and deformation of the clot so that the clot can travel through the chamber.

[0027] The various aspects of the suction system are described below.

[0028] We also describe a method using a suction system according to any embodiment, in which a controller changes the suction pressure during clot suction. A chamber pressure sensor may be present, and the controller changes the suction pressure based on the sensed pressure within the catheter chamber. A chamber fluid flow sensor may be present, and the controller changes the suction pressure based on the sensed fluid flow rate within the chamber. Preferably, the controller improves suction efficiency by preventing catheter blockage and / or promotes softening and deformation of the clot to allow it to travel through the chamber. Furthermore, the controller may provide a vacuum or positive pressure based on measured pressure and change direction to alter the pressure and fluid flow rate.

[0029] The controller may have upper and lower limits for pressure or displacement to determine whether to apply vacuum or pressure, and / or the controller may cause the catheter to periodically take in and, if necessary, expel at least some of the clot, thereby deforming the clot to improve suction efficiency and prevent catheter blockage. The controller may begin to create some vacuum to measure negative pressure, which, in the absence of occlusion or partial occlusion at the catheter tip, will be the nominal reading indicating free flow of fluid through the catheter, and an increase in vacuum will be observed once the catheter advances and engages with the clot.

[0030] The controller can increase the vacuum to draw in more clots and reverse at the lower pressure limit, which is set such that during the vacuum period, a portion of the clots has been drawn in, but not so much that the clots become irreversibly blocked. The lower vacuum limit can be set above the full vacuum pressure to prevent the draw in of excessively large clots that could block the conduit.

[0031] Other aspects of the operation of the suction system are set below. For example, the controller may be set with a lower limit between -100 mmHg and -200 mmHg, preferably between -200 mmHg and -300 mmHg, more preferably between -400 mmHg and -500 mmHg, and even more preferably between -600 mmHg and -700 mmHg; and this may cause the direction of fluid discharge from the pump to reverse, thereby increasing the measured pressure and unloading the clumps. Attached Figure Description

[0032] The invention will be more clearly understood through the following description of some embodiments of the invention given by way of example only with reference to the accompanying drawings, in which:

[0033] Figure 1 This is a schematic cross-sectional view of the distal end of the catheter;

[0034] Figure 2 It is a cross-sectional view of a portion of the conduit wall with varying corrugation depth;

[0035] Figure 3 Show Figure 1 The outer surface of the catheter shown;

[0036] Figure 4 yes Figure 1 The cross-sectional view of the entire catheter shown;

[0037] Figure 5 This is a schematic cross-sectional view of a portion of the catheter wall, which has an outer tubular layer that is connected to an inner tubular layer.

[0038] Figure 6 It is a schematic cross-sectional view of the transition between the distal and proximal wall portions;

[0039] Figure 7 This is a schematic cross-sectional view of another transition between the distal and proximal wall portions;

[0040] Figure 8 The force measured with a displacement of 1 mm is shown in a 3-point bending test in a conventional catheter design (0.80A urethane sheath on top of a 0.005 in NiTi coil, and a 0.005 in NiTi coil on top of a 0.001 in PTFE liner) and a highly flexible corrugated ePTFE design.

[0041] Figure 9 This demonstrates the behavior of a conventional catheter under compression when pushed towards a constraint, and Figure 10 This illustrates the behavior of a corrugated conduit under compression when pushed toward a constraint.

[0042] Figure 11 The use of a catheter is shown in the distal portion toward the proximal part, in the distal end of the catheter wall, in a gradually more flexible (or less "pushable") section.

[0043] Figure 12 It is a cross-sectional view through the outer wall and inner lining with a corrugated surface;

[0044] Figure 13 A cross-sectional view through the catheter is shown, wherein the liner terminates before the distal end of the catheter;

[0045] Figure 14 A cross-section of the catheter is shown, in which the helical support is not exposed in the inner chamber of the catheter;

[0046] Figure 15 Further structural details of the catheter wall are shown to achieve the desired flexibility at the proximal and distal portions;

[0047] Figure 16 The outer tubular layer added to the outside of the corrugated structure is shown, which is embedded with a helical support to further increase the stiffness of the proximal segment of the conduit toward the distal end.

[0048] Figure 17 The manufacturing steps of a corrugated conduit segment with a polymer sheath are shown.

[0049] Figure 18 The diagram shows a conduit portion having a liner, coils, an inner tubular layer and an outer tubular layer, and filler for increasing stiffness;

[0050] Figure 19 This shows that the thickness of both the inner and outer tubular layers is increased; in this case, the coil can float or be constrained between the outer layer and the inner liner.

[0051] Figure 20 The diagram shows a conduit portion having a pad, an outer sheath layer below the coil, and two layers outside the coil; in this case, the coil can float or be constrained within the sheath material.

[0052] Figure 21 This illustrates how multiple layers are overlapped to achieve precise levels of stiffness in order to achieve controlled variations in the stiffness of the distal end; in this case, the coil can float or be constrained within the sheath material.

[0053] Figure 22 This is a graph showing the results of a three-point bending test to evaluate stiffness;

[0054] Figure 23 The farthest end of the distal portion is shown, which is completed by inverting the inner liner over the helical support to form a continuous element; in this case, the coil can float or be constrained in the sheath material;

[0055] Figure 24 The distal portion is shown, wherein flexibility is enhanced by extending the inner and outer tubular layers beyond the final coil of the helical support; in this case, the coil can float or be constrained within the sheath material.

[0056] Figure 25A and Figure 25B Another example of a catheter arrangement is shown, in which the inner liner is inverted to return as a continuous element; in this case, the coil can float or be constrained within the sheath material.

[0057] Figure 26The diagram shows a catheter with a proximal and intermediate portion, with an inner tubular layer of ePTFE material extending along the entire length of the catheter, including the distal end, the inner tubular layer bending backward at the distal end for continuity;

[0058] Figure 27 The inner tubular layer is shown, which has ePTFE in the distal portion of the catheter and PTFE in the more proximal portion of the catheter; a butt joint is used, in which the proximal liner is concentric within the distal liner;

[0059] Figure 28 The proximal region of the rib and concave corrugation is shown, which has an outer tubular layer made of polymer material and a distal liner transitioning to a different material; an overlap joint is used in which the distal liner is concentric within the proximal liner;

[0060] Figure 29 This shows that the ePTFE is concentric within the PTFE over a distance;

[0061] Figure 30 Another arrangement of the helical support in the sheath is shown, wherein the helical support is composed of a tubular layer of nitinol or other material over a non-transmissive material (e.g., platinum); in this case, the coil can be floating or embedded.

[0062] Figure 31 The catheter shown has radiopaque markers at various locations along its length;

[0063] Figure 32 This is a series of figures illustrating typical prior art setups of balloon guiding catheters for providing proximal flow occlusion during thrombectomy procedures;

[0064] Figure 33 This illustrates a balloon catheter with an enhanced flexible segment at the distal end, and

[0065] Figure 34 It is shown Figure 33 Diagram of the layers and chambers of a double-lumen balloon catheter;

[0066] Figure 35 and Figure 36 The bellows tip used to enhance flexibility is shown;

[0067] Figure 37 The left image shows an angiography image of the external carotid artery, common carotid artery, and internal carotid artery (ICA) including segments C1 and C2, while the right image shows an acceptable balloon location.

[0068] Figure 38The diagram shows a proximal shaft and a distal shaft with the same outer diameter, and a proximal shaft with two concentric chambers, wherein the diameter of the central chamber is smaller than the diameter of the flexible distal end.

[0069] Figure 39 A catheter with a balloon and a distal portion is shown, the outer diameter of which is smaller than the outer diameter of the proximal portion;

[0070] Figure 40 The catheter shown has a non-corrugated proximal region in the distal segment;

[0071] Figure 41 The catheter device shown has a radiopaque marker at the distal end of the flexible distal tip;

[0072] Figure 42 The diagram illustrates the setup of a mother-daughter catheter, where the larger catheter is used to block the inflow to the target blood vessel, while the smaller catheter is used to collect the clot.

[0073] Figure 43 The left figure illustrates the inability of a small catheter to reach the distal target vessel during drug or embolization delivery (right); and the resulting undesirable delivery to a non-target vessel (upper left vessel); while the right figure illustrates a method in which a highly flexible, large-diameter catheter is selected to effectively occlude the target vessel, and the large-diameter catheter can be placed outside the non-target vessel, thus delivering the embolization only to the target vessel; preferably, the catheter is wedged into the target vessel;

[0074] Figures 44(a) to 44(e) are schematic diagrams outlining the relationship between pressure and clot behavior in the catheter chamber during aspiration;

[0075] Figure 45 A mechanism for using a pump to draw clots or other substances from the body is shown;

[0076] Figure 46 It is a flowchart showing the steps, including pressure monitoring, to determine whether the pump should apply vacuum or pressure during the suction process;

[0077] Figures 47(a) to 47(n) are diagrams illustrating the operation of the clot removal apparatus in each example;

[0078] Figures 48(a) to 48(c) show the pressure signals that vary between the two vacuum levels;

[0079] Figure 49 It is a flowchart showing the method steps for using positive oscillation or vibration signals;

[0080] Figures 50(a) and 50(b) are graphs showing the vibration signals;

[0081] Figures 51(a) and 51(b) are flowcharts and related diagrams for vacuum and positive oscillation;

[0082] Figures 52(a) and 52(b) are flowcharts and related diagrams for positive and negative pump modulation; and

[0083] Figures 53(a) and 53(b) are pictures of the pump and its components, including the housing, connecting pipe, on / off switch, battery pack, pulsating pump and motherboard, wherein a pressure sensor is connected to the pipe (or “chamber”), which is connected to the conduit, thereby allowing the pressure inside the conduit to be measured. Detailed Implementation

[0084] For illustrative purposes, various embodiments are depicted in the accompanying drawings, and should in no way be construed as limiting the scope of the embodiments. Furthermore, various features of different disclosed embodiments can be combined to form other embodiments, as is part of this application.

[0085] the term

[0086] "Sheath" refers to the catheter wall, and these terms are interchangeable. The sheath may be corrugated in all or some areas along its length (longitudinal direction). The sheath may include any or all helical supports (or "coils") and liner surrounded by sheath material. The liner (where present) defines the chamber, but in other respects other sheath materials define the chamber. The liner (where present) may terminate at certain locations within the catheter.

[0087] The "tubular layer" is the material layer of the sheath.

[0088] "Propellability" is understood as the transmission of force and / or displacement applied along the length of the duct from the proximal portion to the more distal portion. Higher bending stiffness results in greater propulsion.

[0089] "Waves" are the geometric shapes of ribs and recesses on the outer surface of a conduit, usually in a spiral pattern.

[0090] "Distal" refers to the side that is farther from the clinician during use and closer to the catheter tip in the longitudinal direction, while "proximal" refers to the side that is closer to the clinician.

[0091] Description of Implementation

[0092] Figure 1An embodiment of a highly flexible, torsion-resistant catheter 1 is shown. The catheter 1 includes a distal portion 3, a proximal portion 2, a central chamber 5, and a reinforcing structure extending along the length of the catheter, such as a helical support 6. In various embodiments, the proximal portion and the transition portion between the proximal and / or distal portions may include any corresponding features of the catheter described in U.S. Application No. 15 / 647,763, filed July 12, 2017, entitled “HIGH FLEXIBILITY, KINK RESISTANT CATHETER SHAFT,” which is appended to the appendix. The inner and / or outer tubular layers may include PTFE, ePTFE, electrospun PTFE, silicone, latex, TecoThane, nylon, PET, Carbothane (Bionate), SIBS, Tecoflex, Pellethane, PGLA or Kynar, polyethylene and cyclic olefin copolymers, and PEEK.

[0093] At least in the distal portion, the inner tubular layer and the outer tubular layer ( Figure 1 The tubular layer 11 can be formed from a single segment of material or from multiple segments of similar or different materials. In this embodiment, the outer tubular layer 11 of the distal portion is formed of polyurethane (e.g., Pellethane 80AE), while the inner tubular layer 5 is formed of ePTFE and / or PTFE.

[0094] In this configuration, the catheter sheath comprises an inner liner 5 and an outer tubular layer 11 with helical supports 6. The highly flexible distal portion 3 (left side) of the catheter is formed by creating corrugations 15 in the outer surface of the outer tubular layer 11. Figure 1 As shown, the helical support 6 is encapsulated between the corrugations of the outer tubular layer 11 and the outer side of the smooth inner tubular layer 5. The corrugated wall structure formed during bending provides flexibility while reducing the likelihood of twisting. The corrugated outer surface also reduces resistance when the outer surface of the catheter contacts the vessel wall. The depth of the corrugations can be adjusted to provide the desired stiffness variation along the length of the catheter, such as... Figure 2 As shown.

[0095] like Figure 1 As shown, parameter "D" is the depth of the corrugations, and parameter "W" is the width of the corrugations. The width is not the distance from peak to peak, but rather the effective width of the troughs. In practice, for many implementations, this is provided through the manufacturing process: tensioning a binding wire around the tubular layer, heat treatment, and removing the binding wire to provide a corrugated surface. In this case, the width W is approximately equal to the diameter of the binding wire. The depth D is not necessarily uniform because the pressure applied by the binding wire can vary along the length of the conduit, resulting in deeper notches in some locations than in others.

[0096] Figure 2 A cross-section is shown through the wall of the conduit tip 50, which has an inner layer 51, a helical coil support structure 52, and an outer layer 53 with a corrugated surface 53. The corrugation depth A on the left-hand side is greater than the corrugation depth B on the right-hand side. The section with the lower corrugation depth B can be used as a transition region before the tip (left-hand side) with greater flexibility.

[0097] exist Figure 1 and Figure 3 In the example, the coil is embedded in the sheath; movement relative to the surrounding sheath material is restricted.

[0098] Additionally, variations in pitch or corrugation width can be used to locally control flexibility within corrugated areas. Similarly, flexibility can be configured during manufacturing by selecting coils of a certain length that are embedded in or floated within the sheath; areas with floating coils exhibit greater flexibility. In the case of floating coils, the coil is situated within the tubular sheath layer, attached to the space between the corrugated ribs, such as the space between the tubular sheath layer and the gasket.

[0099] The outer tubular layer may extend at least along the proximal (mid) length of the highly flexible distal portion or extend beyond the distal portion by a certain distance, or the outer tubular layer may extend the entire length of the duct, such as... Figure 3 and Figure 4 As shown (it is shown) Figure 1 (The entire length of the catheter). Extending the outer tubular layer beyond the highly flexible distal portion of the catheter by at least a certain length allows for a controlled stiffness transition between the distal and proximal portions of the catheter and allows for a robust joint between the outer tubular layer and any additional outer sheath material. Similarly, flexibility can be established during manufacturing by selecting coils of a certain length to be embedded in the sheath or to float them, as referenced. Figure 3 or Figure 4 The same applies to any of the described implementations.

[0100] To create corrugations in a tubular membrane, the membrane is first placed on a helical reinforcing structure. Upon application of heat, the outer tubular membrane recirculates, forming around the helical structure. Tensile wire is then wound around the outside of the tubular membrane, pressing a portion of the membrane into grooves between the rings supporting the helical structure. The tubular membrane can then be heat-set to fix the corrugations in place. After this process, the tensioned wire can be unwound, leaving the corrugations.

[0101] The inner tubular layer can extend into the proximal portion of the catheter to provide an uninterrupted chamber and to engage or enhance the engagement strength between the highly flexible distal portion of the catheter and the proximal portion. The diameter of the inner tubular layer can be constant (e.g., a smooth surface). Figure 4As shown, the inner tubular layer can form at least part or all of the liner. The inner tubular layer can be made of a low-friction material such as ePTFE or PTFE.

[0102] As described above, at least the distal portion of the outer tubular layer is formed of polyurethane (e.g., Pellethane 80AE), while the inner tubular layer is formed of ePTFE and / or PTFE liner. These layers need to be attached together, which is difficult to achieve because the fluoropolymer does not form a strong bond with other materials.

[0103] To facilitate bonding between fluoropolymers (e.g., ePTFE and PTFE) and between fluoropolymers and other polymers (such as polyurethane, e.g., Pellethane), the outer or bonding surfaces of the fluoropolymers can be chemically treated using a sodium-based etching solution (e.g., FluoroEtch). The etching solution removes fluorine atoms from the surface of the fluoropolymer, making it ready for bonding.

[0104] Then, a thin layer of urethane, such as ChronoFlex, can be coated onto the etched fluoropolymer. When heat is applied, this ChronoFlex layer flows and acts to bond the fluoropolymer to a second etched fluoropolymer layer or another different polymer layer, such as... Figure 5 As shown. This incorporates a coil.

[0105] This figure shows a portion of the cross-section of the catheter at the distal portion 150. This includes a liner 151 of ePTFE or PTFE, and an adhesive layer 152 of urethane or FEP tape or FEP powder. Additionally, Nitinol is present in the outer sheath 154 made of ePTFE or urethane material. TM Coil 153. The Nitinol coil 153 is encapsulated between an outer tubular corrugated layer and a smooth inner tubular layer 151. An adhesive layer 151 is used to attach the gasket 151 to the outer sheath material. If the gasket is ePTFE material, the gasket needs to be etched to remove fluorine atoms so that the gasket and adhesive layer can form a better bond.

[0106] Furthermore, flexibility can be achieved during manufacturing by selecting coils of a certain length to be embedded in or floated within the sheath, as shown in the following reference. Figure 6 and Figure 7 The situation of any of the described implementations.

[0107] ChronoFlex TMThe adhesive layer 152 is very thin and does not cause any significant change in wall thickness. Another form of adhesive layer includes the use of FEP. Fluoropolymers can be sputtered with FEP powder, which forms a bond between the coated fluoropolymer layer and the second layer under heat and pressure. Ultra-thin FEP tapes can also be used in the same application.

[0108] like Figure 5 As shown, a helical support is encapsulated between a corrugated outer tubular layer and a smooth inner tubular layer. The inner and outer tubular layers are bonded together in the space between adjacent rings of the helical support via a mechanism such as an adhesive layer. The helical support is bonded within a helical channel formed by the corrugated outer tubular layer; that is, the helical support is molecularly or physically attached to the outer tubular layer. The helical support can also be bonded to the outer surface of the smooth inner tubular layer. Due to the inherent advantages of the corrugated outer structure and the use of materials with appropriate stiffness and thickness, the distal portion of the conduit maintains high flexibility and resistance to torsion.

[0109] In this configuration, the pitch of the helical support can vary along the entire length of the conduit to affect its bending stiffness. For example, the helical support can have a different pitch at the proximal ring compared to the distal ring.

[0110] If the outer tubular layer of the distal portion of the catheter is formed of a fluoropolymer such as ePTFE or PTFE, while the outer tubular layer of the proximal portion is formed of a different polymer, achieving good bonding can be difficult, especially resisting delamination during tracking. Figure 6 As shown, this problem can be solved by sandwiching the outer layer of the proximal portion of the catheter between the inner tubular layer and the outer tubular layer of the distal portion of the catheter.

[0111] Figure 6 A portion 200 of the catheter is shown, having a padded inner chamber 201, an outer layer 203 of Pellethane 80AE material, and a Nitinol coil 206. On the right-hand side, the catheter has a smooth outer surface 203, and distally in the transition section, the catheter has shallow corrugations 204, and deeper corrugations 205 towards the distal side for greater flexibility. This arrangement, with a transition section between the proximal and distal sections, can be referred to as a "clamping arrangement."

[0112] If the inner tubular layer of the distal portion of the duct is formed of a different material or a different material segment than the inner tubular layer of the proximal portion, the tubular layers can be joined by forming a small slit or window in one tubular layer and pulling the splice length of another tubular layer through that slit or window, such as... Figure 7 As shown. Then, the spiral support is wound around the outside of these layers to hold them together.

[0113] Figure 7 The diagram shows a duct segment 250 having a proximal end 251, a transition section 252 and a distal end 253, and a spliced ​​adjacent layer 260 having a window 261.

[0114] In various embodiments, the helical support is physically attached by being constrained or embedded in the conduit wall to move together with the wall material surrounding the conduit wall. Such embedding can be achieved at the interface between the coil and only the sheath material, or at a combination of the interface between the sheath material and the gasket.

[0115] Embedding is achieved through a very tight fit between the coil and the surrounding material. Typically, there are no gaps between the coil and the surrounding wall material. Due to the three-dimensional geometry of the coil, it cannot move independently while embedded in the surrounding material.

[0116] Because of the manufacturing technology that allows the material to be molded around the coil, there is no gap between the coil and the sheath, meaning it cannot move independently. In other words, the coil is stationary unless the surrounding sheath material moves or deforms simultaneously.

[0117] This lack of clearance and tight fit means that there is interfacial friction between the coil and the surrounding material, which further provides constraint, meaning that the coil and the surrounding material must move together.

[0118] In other embodiments, the coil can be floating, meaning there is no tight fit between the material in the sheath and the helical coil. In these cases, there will be some gap between the helical support and the sheath. This is especially true when the sheath material surrounding the helical support is made of ePTFE. In this case, even with a relatively tight geometric fit, the material is quite flexible and allows the helical support to move relative to the ePTFE.

[0119] Generally, the following are some preferred parameter ranges for catheters.

[0120] For at least some lengths of the catheter, the width of the corrugations shall not exceed 50% of the corrugation pitch.

[0121] For at least some length of the catheter, the width of the corrugations is between 5% and 49% of the corrugation pitch, and more preferably, the width of the corrugations is between 15% and 45% of the corrugation pitch.

[0122] For at least some length of the catheter, the width of the corrugations is between 20% and 45% of the corrugation pitch.

[0123] For at least some length of the catheter, the width of the corrugations is at least 10% of the sheath thickness.

[0124] For at least some length of the catheter, the width of the corrugations is at least 20% of the sheath thickness.

[0125] At the farthest region of the distal portion, the width of the corrugations is at least 60% of the sheath thickness.

[0126] At the farthest region of the distal portion, the width of the corrugations is at least 60% of the wall thickness, and the depth of the corrugations is at least 70% of the wall thickness.

[0127] In at least one region of the conduit, the ratio of the width of the corrugations to the depth of the corrugations is at least 0.5.

[0128] In the embodiments described below, unless otherwise stated, the coil may be embedded or floated in some or all areas of the conduit.

[0129] Referring again to the catheter structure configuration, we obtained a catheter with a highly flexible distal tip to ensure a smooth transition in bending stiffness and maneuverability between the flexible distal and proximal portions of the catheter. This smooth transition can be of a more conventional structure. The smooth transition prevents stress and strain concentration areas within the catheter axis. Such areas could lead to catheter twisting, delamination of material layers, and / or damage to critical bonds within the catheter.

[0130] Benchmark tests show a significant difference in stiffness between conventional catheter tip designs and highly flexible corrugated designs. Successfully bridging this gap presents a technical challenge.

[0131] Figure 8 The diagram illustrates both conventional catheter designs (0.80A urethane sheath, situated above a 0.005 in NiTi coil, which is positioned at a pitch of 0.018 in (0.45 mm) above a 0.001 in (0.025 mm) PTFE liner) and highly flexible corrugated ePTFE designs (0.002 in (0.05 mm) ePTFE for both inner and outer walls, with a density of 0.9 g / cm³). 3 The force was measured with a displacement of 1 mm in a 3-point bending test with a 0.005 in (0.125 mm) NiTi coil and a 0.018 in (0.45 mm) pitch.

[0132] It should be understood that while excellent catheter axis flexibility allows the catheter to travel with low force in extremely tortuous bends and reduces the likelihood of vascular injury, this may also lead to some trade-offs in propulsion. For clarity, propulsion is understood as the transmission of force and / or displacement applied at the proximal portion of the catheter to the distal portion along the entire length of the catheter.

[0133] Catheter flexibility can limit the transfer of displacement applied at the proximal portion of the catheter to the distal portion. This means that a portion of the displacement is absorbed through overall catheter deformation, such as... Figure 9 As shown. Figure 9 This illustrates the behavior of a standard catheter under compression when pushed towards a constraint. In this example, the length of catheter 600 remains unchanged. Typically, this type of shortening occurs in catheters with a standard construction.

[0134] Figure 10 This illustrates the behavior of the corrugated catheter 650 under compression when pushed towards a restriction. With a corrugated outer sheath having thin inner and outer tubular layers, deformation can be accommodated by the catheter wall. The inner and / or outer tubular layers of the catheter can deform locally, particularly in recesses, meaning a reduction in overall length. (As shown...) Figure 9 As shown, some overall deformation of the catheter is also to be expected.

[0135] This soft compression behavior is advantageous at the distal tip because the ability to move the catheter tip forward to cause vascular injury or dissection is limited. However, in cases where the distal tip is very long, it is preferable to add some propulsion in the proximal portion of the tip to allow the physician to guide the catheter as intended, both distally and proximally.

[0136] In one configuration, there are one or more regions with different propulsion and flexibility at the tip of the duct, the one or more regions being composed of one or more regions with rib and recess structures. Figure 11 This illustrates a progressively more flexible or less kinetic segment of the catheter wall 701 distal to the proximal portion 702 within the catheter 700. In one configuration, the most flexible region is at the distal tip of the catheter.

[0137] These areas of increased / decreased propulsion / bending stiffness are achieved through a number of features, such as embedding helical supports, altering the inner and outer tubular layers (where the helical supports may or may not float between the inner and outer tubular layers), or using filler materials.

[0138] Changing stiffness or propulsion through transition regions can be done gradually or via multiple steps. Stepped or gradual changes can be achieved by terminating specific tubular layers, or by altering the degree of corrugation or changing the material.

[0139] It is conceivable that any or all of these methods can be combined on some or all of the catheter axis. Examples are as follows:

[0140] A distal end, at least some of which is a corrugated material embedded with helical supports, wherein the degree of corrugation gradually changes proximally to achieve an increase in stiffness. The distal region may or may not have a gasket. The gasket is ePTFE, transitioning to PTFE in the more proximal regions. The closest portion may not be corrugated.

[0141] A distal end, wherein at least some of it comprises floating coils between layers of ePTFE with a corrugated design, wherein the thickness of the ePTFE material gradually increases or steps towards the proximal side. This can be achieved by increasing the wall layer thickness or by adding layers of material. The ePTFE liner transitions to PTFE in the more proximal region. The closest portion may not have corrugations.

[0142] The distal region may include floating coils between corrugated ePTFE layers, a corrugated embedded portion closer to the edge, and a non-corrugated portion even closer to the edge. The ePTFE liner transitions to PTFE in the closer region. The distal corrugated region may be combined with a closer corrugated region with increased wall thickness, or an additional layer of material may be added to the wall to increase stiffness. The closest portion may not be corrugated.

[0143] In one configuration, the helical support is embedded by being bonded to a sheath made of, for example, ePTFE material. This has the effect of stiffening the duct wall structure compared to a floating helical support, thereby reducing flexibility and increasing propulsion.

[0144] In one configuration, within the conduit portion 750, a helical support 752 is embedded in a matrix 753 of a continuous porous flexible material (such as ePTFE). The outer wall has a corrugated surface, such as... Figure 12 As shown. An inner tubular layer or liner 751 may not be necessary, as... Figure 12 As shown.

[0145] ePTFE not only provides a very soft and flexible material in ductal structures, but it is also compressible due to its porosity. Furthermore, when used as a thin tubular layer that is easily deformable locally, macroscopic propulsion may be compromised if the ductal region is hindered, especially at the distal tip. To improve propulsion while maintaining high flexibility, incompressible flexible materials can be used instead of porous materials such as ePTFE for embedding. This means that porous materials are more adaptable to deformation compared to non-porous materials.

[0146] The corrugations allow for localized deformation, while the continuous, incompressible material areas ensure the efficient transmission of axial forces and displacements along the length of the conduit. By reducing the depth of the corrugations and correspondingly increasing the thickness of the continuous material, the conduit's propulsionability can be increased while reducing flexibility. This can be described as a corrugated sheath design.

[0147] In one embodiment, the inner tubular layer is made of ePTFE. In one configuration, the helical support is offset from the liner so that it is not exposed to the liner. This is to prevent the helical support from moving or detaching and to prevent it from applying localized stress or strain to the liner of the conduit. The corrugated geometry can be semi-circular, U-shaped, V-shaped, or square.

[0148] In one configuration, the width of the corrugations at the surface of the conduit is at least 5% of the wall thickness. Preferably, in at least one section, the width of the corrugations at the surface of the conduit is at least 10% of the wall thickness. Preferably, in at least one region of the distal tip, the width of the corrugations at the surface of the conduit is at least 30% of the wall thickness.

[0149] In one embodiment, the corrugation depth is between 5% and 95% of the catheter wall thickness. In one configuration, the corrugation depth is at least 20% of the catheter wall thickness in at least one section of the catheter.

[0150] In one embodiment, the corrugation depth varies along the corrugated region of the catheter from a greater depth distally to a smaller depth proximally. In another embodiment, the corrugation width varies along the corrugated region of the catheter from a greater depth distally to a smaller depth proximally. In yet another embodiment, the corrugation depth varies from a greater depth distally to a smaller depth proximally, while the width remains substantially constant along the length of the corrugated section of the catheter.

[0151] In one embodiment, the corrugations are manifested as imprints of a circular spiral wire, the imprints of which range from a depth and width of no imprint, i.e., no corrugations winding to a depth of at least 50% of the wall thickness. In that case, it should be understood that the width of the corrugations varies from 0 to a maximum width equal to the diameter of the spiral wire, or from 0 to an imprint that remains after the spiral wire is removed.

[0152] It should be understood that tension needs to be applied to the wound, bound helical wire to create corrugations. For example, winding a 0.005-inch round cross-section 304 stainless steel wire with a 1N tension around an 80A sheath with an inner diameter of 0.088 inches and a wall thickness of 0.006 inches with a force of 1N will achieve a corrugation depth of 10-20%. Increasing the tension to 7N while winding with a 1N tension will achieve a corrugation depth of 40-70%. Different levels of force will cause different degrees of corrugation. It should be understood that, as Figure 1 The high-depth D corrugations shown will allow the catheter segment to flex with relatively small forces. This is because the overall bending of the catheter is actually concentrated within the recesses of the corrugations.

[0153] However, if the corrugations have a very small width, even very deep and numerous corrugations will limit the degree of bending the conduit can accommodate. This is because adjacent corrugations will begin to contact each other. Therefore, the bending stiffness will remain low until adjacent corrugations contact each other or "bottom out," at which point the bending stiffness will increase. Bending will then be accommodated by deformation of the rest of the conduit wall (and no longer primarily within the recesses).

[0154] This bottoming out means that the guide shaft has a lower limit to its bending radius, which can be achieved through deformation within the recess. Further bending deformation beyond the bottoming-out limit is possible, but cannot be accommodated by deformation at the recess of the corrugations; this deformation is accommodated by pressing adjacent corrugations against each other. This typically involves very high forces compared to deformation occurring with a lower bending radius when the deformation is concentrated in the recess.

[0155] The width of the corrugations should be controlled to be large enough to accommodate sufficient deformation within the concave area, thereby achieving the desired lower limit of the bending radius with relatively low bending forces. This is important because physicians typically want to be able to guide the catheter with lower forces to reduce the possibility of vascular injury and to prevent the catheter from deforming the vessel as it moves forward.

[0156] While the width and depth of the corrugations contribute to the duct's bending stiffness, the width dominates the lower limit of the duct's deformable bending radius. Therefore, a larger corrugation width can achieve a smaller bending radius at lower bending forces.

[0157] Consider an example of a conduit with an inner diameter of 0.088 in (2.2 mm) and a wall thickness of 0.006 in (0.15 mm), featuring a Nitinol helical support with a diameter of 0.005 in (0.125 mm), embedded in an 80A tube at a pitch of 0.018 in, situated on an ePTFE liner. A sample with a corrugation width of 0.004 in (0.1 mm) and a corrugation depth of 0.006 in will generate a 3-point bending force of 0.05 N at a 1 mm deflection, and a bottoming-out bending radius of 5 mm. A sample with a corrugation width of 0.007 in (0.175) and a corrugation depth of 0.006 in will generate a similar force at 3-point bending, but with a bottoming-out bending radius of 3.5 mm.

[0158] To enable large catheters to safely enter cerebral blood vessels and accommodate bends with lower radii, such as those in the carotid siphon segment, the width of the corrugations should have a minimum relative to the pitch and / or wall thickness.

[0159] In one embodiment, the width of the corrugations is no greater than 50% of the corrugation pitch (the same as the pitch of the helical support). Preferably, the width of the corrugations is between 5% and 49% of the corrugation spacing. More preferably, the width of the corrugations is between 15% and 45% of the corrugations. Even more preferably, the width of the corrugations is between 20% and 45% of the corrugations.

[0160] In one embodiment, the width of the corrugations is at least 10% of the wall thickness. Preferably, the width of the corrugations is at least 20% of the wall thickness. In one embodiment, at the farthest end of the corrugations, the width of the corrugations is at least 60% of the wall thickness.

[0161] In one embodiment, in the farthest section at the tip, the width of the corrugations is at least 60% of the wall thickness, and the depth of the corrugations is at least 70% of the wall thickness.

[0162] In another embodiment, the ripples are manifested as the imprint of a circular spiral that extends from a depth and width without an imprint (i.e., without ripples) to a depth of at least 70% of the wall thickness.

[0163] In one configuration, the inner tubular layer (liner) terminates in a region near the distal end of the catheter. For corrugated or non-corrugated configurations, this further reduces the stiffness of the catheter. In this case, especially when the catheter wall is made of materials such as silicone, polyurethane, or Pebax, the unlined area may become sticky. In one embodiment, the inner chamber region of the unlined catheter has a hydrophilic or hydrophobic coating to improve lubrication. This is in… Figure 13 The image shows a catheter portion 760 having a helical support 761 embedded in an outer sheath 762, and wherein a liner 763 extends a portion of that length but terminates before the distal end (left side).

[0164] In one embodiment, the length of the unlined section is at least 1 cm, preferably at least 2 cm. The lining termination is advantageous in allowing for more flexible sections of the conduit. However, this can also lead to abrupt changes in bending stiffness and the location of possible torsional kinks or high stress or strain. This can be addressed by changing the corrugation parameters or thinning the lining. In another embodiment, the lining termination is a thin sheet or an angled cut.

[0165] In one configuration, the section of unpadded sheath material adjacent to the liner on the proximal side has less corrugation than the distal and proximal sections of the unpadded sheath. This can be achieved by reducing the corrugation depth. In another configuration, the corrugated section of the liner adjacent to the unpadded sheath has a longer pitch than the distal and proximal sections of the unpadded sheath.

[0166] In one configuration, the helical support is offset from the inner liner so that the helical support is not exposed within the catheter's inner lumen, such as... Figure 14 As shown, a helical support 771 is provided in the outer sheath 772. This is to prevent the helical support from popping out into the catheter chamber during catheter bending. In one embodiment, the distance from the inner chamber to the helical support is at least 0.005 mm.

[0167] Reference Figure 15 The conduit portion 780 contains a helical support 781, an outer sheath 782, and an inner liner 783. The outer sheath 783 has a non-corrugated proximal portion 784 and a corrugated distal portion 785. The inner liner 783 terminates proximally at the distal end 786. This is an example of a construction in which the most distal segment of the distal end is composed of a corrugated sheath without a liner, a more proximal segment is corrugated and includes a liner, at least one more proximal segment has larger corrugations, and at least one more proximal segment is again non-corrugated. In one embodiment, all segments of the sheath have the same material hardness. In one embodiment, the material is urethane with a hardness of 80A. In another embodiment, a more proximal sheath is made of a harder urethane or pebax. The liner is made of ePTFE. In the more proximal segments of the shaft, the liner may transition to PTFE. In one implementation, this transition is made with a material that is harder than the sheath of the corrugated distal tip.

[0168] In one embodiment, the conduit portion 800 has a liner 751, a helical support 752, and an outer sheath 753 in relation to the conduit portion 750. However, in this case, an outer tubular layer 801 is added to the outside of the corrugated structure, such as Figure 16 As shown, the outer tubular layer 801 is embedded in the helical support to further increase the stiffness of the distal-to-proximal conduit segment. The material of this layer may be the same as or different from the material used to encapsulate the helical support. In this case, a high-stiffness material, such as PET or Nylon pr PEEK or other polymers, can be used without significantly increasing the profile. In one embodiment, a PET layer is added, with a thickness of 0.05 mm or less, preferably 0.025 mm or less, more preferably 0.0125 mm or less.

[0169] Several methods can be used to manufacture corrugated catheter segments with polymer sheaths. The following steps can be used, such as... Figure 17 As shown:

[0170] A conventional catheter structure is established, comprising a coil 752 embedded within a polymer sheath 753, which is bonded to a PTFE liner 751 to form a base component.

[0171] Then, an outer liner 811 that does not bind to the polymer sheath is placed on the sheathed coil. A highly flexible fluoropolymer, such as FEP or PTFE, or more preferably, ePTFE, can be used.

[0172] Under tension, wire 810 is wound in a spiral shape around the outside of the outer pad to apply a corrugated geometry to the structure. This can be referred to as "bonded wire".

[0173] The structure is heated to reflow or anneal the material, thereby setting the structure into a corrugated geometry.

[0174] Cooling components.

[0175] Remove the binding cable 810.

[0176] The process is completed by peeling the outer liner 811 off the component.

[0177] Filler material can also be used to manage flexibility and increase propulsion, and can be used to embed coils when filler material is used. Figure 18 The conduit portion 850 is shown, which has a liner 851, a coil 852, an inner tubular layer and outer tubular layers 853 and 854, and filler for increasing stiffness.

[0178] In one implementation, the material is used only to partially fill the space around the helical support, such as Figure 18 As shown. In another embodiment, the filler material completely fills the helical channel surrounding the helical support between the inner and outer tubular layers. In yet another embodiment, the filler material is melted to form material layers on all surfaces within the helical channel.

[0179] In one embodiment, the outer tubular layer and the inner tubular layer are made of ePTFE or PTFE, and the filler material is PET, PEEK, or FEP.

[0180] The helical channel is formed using a helically wound wire (binding wire) temporarily placed on the outside of the outer tubular layer. To permanently form the helical channel, the structure can then be heated, causing the filler layer to melt and flow between the helical support, the outer tubular layer, and the inner tubular layer. After cooling and removing the helically wound binding wire from the outer tubular layer, the corrugated structure is maintained, and a chemical bond is achieved between the components via the filler material.

[0181] In one configuration, the filler material may be polyurethane, pebax, PET, silicone, latex, TecoThane, nylon, PET, Carbothane, SIBS, Tecoflex, Pellethane, PGLA or Kynar, polyethylene and cyclic olefin copolymer, PEEK.

[0182] In one configuration, the inner and outer tubular layers of ePTFE are bonded together by sintering. It must be recognized that, particularly when ePTFE or fluoropolymers of PTFE are used as the inner and outer tubular layers, the sintering temperature may exceed 500 °C. In such cases, filler materials with higher processing and degradation temperatures, such as PET, FEP, or PEEK, are preferred. Other materials, such as urethane or pebax, will degrade at lower temperatures and are therefore unsuitable.

[0183] Because PET is a relatively rigid material, it can be introduced in small amounts to stiffen the corrugated structure without significantly affecting the conduit profile or completely filling the helical channel. This provides space for both floating and embedded coils.

[0184] In a construction, propulsion or stiffness can be increased by varying the thickness of one or two tubular layers. Increasing the thickness increases the inherent stiffness of the wall. This also means reducing the available space for localized material bending and deformation. Therefore, flexibility may decrease. Furthermore, with increasing thickness, the axial cross-sectional area along the force transmission axis and the displacement along the duct increase.

[0185] In one implementation, such as Figure 19 As shown, compared to conduit portion 900, the thickness of both the inner and outer tubular layers is increased in conduit portion 950. Conduit portion 900 includes an inner liner 901, a coil 902, and an outer tubular layer 903. Conduit portion 950 includes a thicker inner liner 951, a thicker coil 952, and a thicker outer tubular layer 953. In another embodiment, only the thickness of the inner tubular layer is increased. In yet another embodiment, only the thickness of the outer tubular layer is increased.

[0186] In another construction, the total outer tubular layer wall thickness can be varied by adding one or more layers of the same material. (See reference...) Figure 20 The conduit portion 1000 has a liner 1001, an outer sheath layer 1002 below the coil 1005, and two layers 1003 and 1004 outside the coil 1005.

[0187] The total wall thickness of the inner tubular layer can be increased by adding one or more layers. These layers can be made of the same or different materials. In the case of ePTFE, the bond thickness of the unconstrained inner tubular layer can be between 0.025 mm and 0.3 mm, preferably between 0.05 mm and 0.2 mm.

[0188] In one configuration, the inner and outer tubular layers are composed of multiple layers of ePTFE, with at least one layer existing between the outer and inner tubular layers. The total thickness of the tubular layers (e.g., ePTFE) consisting of one or more layers can be between 0.025 mm and 0.3 mm, preferably between 0.05 mm and 0.2 mm. The density of the material (again, ePTFE) can be approximately 0.9 g / cm³. 3 Increasing or decreasing the density of a material will require a greater or lesser wall thickness to achieve the same effect.

[0189] In another embodiment, the thickness of the inner tubular layer is constant along the length of the duct tip, but the thickness of the outer tubular layer is greater in at least one region. In another embodiment, the thickness of the outer tubular layer increases at least once proximally along the length of the duct tip.

[0190] To achieve controlled variation of the stiffness of the distal extremities, such as Figure 21 As shown, multiple layers can be overlapped to achieve precise stiffness levels, with an additional outer layer 1010 present for a portion of the conduit section. This principle can be applied to any number of layers to achieve desired stiffness variations. Similarly, a single, thicker layer can be used proximally, while a thinner layer is connected to it on the more distal side to achieve the same effect.

[0191] In one embodiment, the tip has an outer tubular layer with a thickness of 0.025 mm to 0.075 mm spanning the length of the tip. A second additional outer tubular layer with a thickness of 0.025 mm to 0.075 mm is present in a more proximal region. A third additional outer tubular layer with a thickness of 0.025 mm to 0.075 mm is present in an even more proximal region. A fourth additional layer with a thickness of 0.025 mm to 0.075 mm is present in an even more proximal region.

[0192] In one embodiment, the distal tip includes an outer tubular layer with a length of 0.05 mm extending throughout the tip. A second additional outer tubular layer with a thickness of 0.05 mm is present in a more proximal region. A third additional outer tubular layer with a thickness of 0.05 mm is present in an even more proximal region. A fourth additional layer with a thickness of 0.05 mm is present in an even more proximal region.

[0193] In one construction, the tubular layers are bonded to each other. This bonding can be present throughout the entire interface of the tubular layers. Alternatively, the bonding can exist only at the recesses of the corrugations, in the region where the inner and outer tubular layers meet. In yet another embodiment, there is bonding between the layers at the ribs and recesses of the corrugations. In yet another embodiment, the material of the inner or outer tubular layers can be changed to have higher stiffness to increase the stiffness of the wall.

[0194] It should be noted that, due to the use of localized compression (pressure) to ensure a strong bond between the tubular layers, some thickness variations in the tubular layers may exist locally after the bonding of the inner and outer tubular layers or their constituent layers. This is especially true for ePTFE, as it is a porous, compressible material. This localized compression can reduce the wall thickness in that region.

[0195] To evaluate a subset of the above embodiments, an 8F conduit sample with an inner diameter of 0.088 in was constructed and tested using a 3-point bending test. The force at a displacement of 1 mm was measured using a 50 N load cell on a Zwick Roel tensile testing machine. The distance between the supports was 20 mm. Significant variations in stiffness can be achieved using the various configurations outlined above.

[0196] It is understood that the above-described embodiments can be used to change the stiffness of the catheter wall as needed. For comparison, the 6F Microvention Sofia Plus catheter for neurovascular systems is included. Figure 22 The results of a three-point bending test used to evaluate the stiffness of the various embodiments described above are shown.

[0197] In the neurovascular system, non-traumatic distal ends are crucial when accessing fragile vessels such as the M1, M2, ICA, vertebral artery, and basilar artery. Preferably, the most flexible segment of the distal end has a minimum length, allowing the catheter tip to deflect or absorb deformation rather than cause vascular damage.

[0198] In one embodiment, the distal and flexible sections of the catheter, designed with corrugated ribs and recesses, have a minimum length of 1 cm and consist of an inner and outer tubular layer with a corrugated structure, and have floating helical supports within the helical channel. In one embodiment of the distal tip of the 8F catheter, the force in a 3-point bending test with a span of 20 mm and a deflection of 1 mm should not exceed 0.1 N.

[0199] like Figure 23 As shown, in one configuration, the distal end 1050 of the distal portion is completed by inverting the inner tubular layer 1051 on the helical support to form a continuous element.

[0200] Reference Figure 24 In another embodiment, in the distal end 1060, the flexibility of the distal end is improved by extending the inner tubular layer and the outer tubular layers 1061 and 1062 beyond the last coil of the helical support.

[0201] like Figure 25AAs shown, in the distal portion 1070, the inner tubular layer 1071 is reversed at the distal end 1072 to return as a continuous element. The inner and outer tubular layers are made of the same material and are continuous. An extension of ePTFE is present at the end 1072 of the corrugated section to improve the flexibility of the tip. Preferably, the extension beyond the last coil is between 0.5 and 5.0 mm. More preferably, the extension beyond the last coil is between 1.0 and 0.3 mm. The distal portion 1070 also has an outer tubular layer 1073 terminating before the distal end 1072 and another concentric outer tubular layer 1074 surrounding layer 1073 for a portion of the length of layer 1073. This staggered overlapping arrangement provides a transitional portion with a stepped change in bending stiffness.

[0202] Figure 25B The distal portion 1080 of the catheter is shown, having an inner liner 1081 that extends at the distal tip to form an extension. In this case, overlapping, staggered outer tubular layers 1083 and 1084 are also present.

[0203] In catheter 1070, two or more layers are achieved by using the same piece of material that is reversed and returned along the length or a portion of the catheter. In one case, two pieces of ePTFE are used to achieve an inner tubular layer and three corrugated outer tubular layers.

[0204] In catheter 1080, additional layers are added discretely. In another embodiment, a combination of inverted continuous and discrete layers is used. The proximal portion of the catheter (shown as non-corrugated) can be corrugated or non-corrugated.

[0205] Compared to eTPFE, PTFE is a relatively rigid material, therefore its use as an inner tubular layer (liner) is preferred, especially in areas where significant bending occurs during passage through tortuous blood vessels. In one embodiment, such as Figure 26 As shown, in a catheter 1100 having a proximal end 1101 and a middle portion 1102, the inner tubular layer has an ePTFE material and extends along the entire length of the catheter including the distal end 1103, in which case the inner tubular layer bends backward to be continuous with the outer tubular layer.

[0206] In one configuration, the inner tubular layer is ePTFE in the distal portion of the catheter and PTFE in the more proximal portion, such as... Figure 27As shown, this is for a catheter 1150 having a proximal end 1151, a middle portion 1152, and a distal portion 1153. There is a transition region 1154 in which a layer of the outer sheath is incorporated into and coupled to the outer sheath of PTFE material in both the middle portion and the transition region. The transition from ePTFE to PTFE can be achieved via a "butt joint" in which the inner tubular layers of PTFE and ePTFE contact without overlapping.

[0207] In another embodiment, the transition from the inner tubular layer of ePTFE to the inner tubular layer of PTFE occurs in an area where the catheter does not undergo significant bending during use. In one configuration, the device is sized to fit within the neurovascular system including M2, M1 and the distal internal carotid artery. Preferably, the transition from ePTFE to PTFE occurs close to the petrous segment of the ICA. In one configuration, the transition from ePTFE to the inner tubular layer of PTFE occurs between 3 cm and 40 cm distal to the catheter, preferably between 5 cm and 30 cm distally, and more preferably at least 10 cm distally.

[0208] In one configuration, the transition from the inner tubular layer of ePTFE to the inner tubular layer of PTFE occurs in a region close to the area of ​​the ribs and corrugated recesses of the conduit. In another configuration, the transition from the inner tubular layer of ePTFE to the inner tubular layer of PTFE occurs near the most flexible region of the rib and corrugated recess design, but still within the region of the stiffer rib and corrugated recess design.

[0209] In one embodiment, the proximal regions of the ribs and concave corrugations have an outer tubular layer made of a polymer material, such as Figure 28 As shown. In one configuration, the polymer material is urethane or Pebax. In one embodiment, the polymer material is 80A urethane. Figure 40 A catheter 1200 is shown, having a proximal end 1201, a middle portion 1202, a distal portion 1203, and a transition region 1204. In the middle portion, within the corrugated section at the distal end, an ePTFE inner tubular layer (liner) 1207 transitions to a PTFE sheath 1205. An overlap joint is used, in which the PTFE tubular layer 1208 is concentric within the ePTFE tubular layer 1207.

[0210] In another embodiment, the transition from ePTFE to PTFE can be achieved via an "overlap" joint, in which tubular layers of ePTFE and PTFE overlap. In one configuration, the overlap length between PTFE and ePTFE is between 1 mm and 30 mm. The use of overlap increases the interfacial area available for bonding, thereby improving bond strength.

[0211] In one example, over a distance, the ePTFE is concentric within the PTFE, such as... Figure 29 As shown in the figure, the conduit 1250 has a proximal end 1251, an intermediate portion 1252, and a distal end 1253. An inner liner 1260 is bent at the distal end to form part of the outer sheath of the distal portion 1253. In the transition region between the intermediate portion 1252 and the distal portion 1253, the inner liner 1260 overlaps with the PTFE material tube 1261 for a length of at least 2 mm, preferably at least 5 mm. The tubular layer 1261 extends proximally within the sheath material 1262 in the intermediate portion 1252. This configuration provides a transition from the ePTFE inner tubular layer (liner) to the PTFE inner tubular layer in the corrugated section at the distal end. An overlap joint is used, in which the ePTFE tubular layer 1260 is concentric within the ePTFE tubular layer 1261.

[0212] In one configuration, a marker consisting of a platinum spiral coil is present at the distal end.

[0213] In one embodiment, the helical support may be made of a radiopaque material, such as platinum wire. In another embodiment, to take advantage of the superelasticity of radiopaque Nitinol, the helical support may be made of drawn Nitinol tubing filled with platinum or other radiopaque materials (e.g., Nitinol #1 DFT from Fort Wayne Metals). This would allow the surgeon to observe the behavior of the distal end under X-ray throughout the procedure. In one embodiment, the helical support tubing is composed of at least 10% platinum. Figure 30 In the illustrated configuration, the conduit portion 1280 has a non-transparent spiral coil 1281, a coating 1282 surrounding the spiral coil, and a tubular layer 1283 on the outer sheath.

[0214] In one construction, the ray impermeability of the distal tip is further enhanced by reducing the pitch of the helical support, thereby obtaining a region with a higher density of ray impermeability.

[0215] Figure 31 The catheter is shown with radiopaque markers 1270 at various locations along its length. An advantage and novel aspect is that it allows physicians to ensure that the stiffer areas of the catheter are not placed in more vulnerable areas of the vascular system. For example, at the origin of the flexible distal end, a proximal marker can be used to define the area of ​​the proximal catheter that should not be placed outside the C1 segment of the internal carotid artery. An intermediate marker can be further used to distinguish the distal end of the intermediate flexible area that should not be placed before, within, or outside the cavernous sinus segment C4. The area between the intermediate and distal markers establishes the most flexible area suitable for placement in the C4-C7 region of the internal carotid artery and further distal vessels.

[0216] In one embodiment, the device is adapted for placement in a neurovascular system, with the distal flexible terminal having a length of at least 10 cm and the unpadded distal segment having a length of at least 3 cm. In another embodiment, the device is adapted for placement in a peripheral vascular system.

[0217] Aspiration devices, including catheters.

[0218] Any example of a catheter can be used, for example, for thrombectomy.

[0219] Recent clinical data suggest that using a balloon-guided catheter for thrombectomy can improve outcomes. This is achieved through the following methods:

[0220] As the balloon approaches the clot in the ICA and expands, it reduces the flow to the clot. This reduced flow decreases the likelihood of distal embolism breakage or distal carryover during clot retrieval using a stent retrieval device or aspiration catheter.

[0221] Once the clot is captured by the stent thrombectomy device or aspiration catheter and pulled from the target site, it enters the BGC to provide a chamber for aspiration.

[0222] exist Figure 32 The diagram schematically illustrates a conventional setup for a balloon guiding catheter in thrombectomy procedures, the balloon guiding catheter having a balloon 1300 and a distal end 1301. Balloon guiding catheters used in thrombectomy procedures must facilitate insertion of microcatheters and distal access catheters. For this purpose, the inner diameter of the balloon guide must be in the range of 5F or larger. Additionally, the catheter typically has an outer diameter in the range of 8F or 9F.

[0223] At these dimensions, existing catheter technology is extremely rigid. This is due to the catheter materials, design, and construction used. Therefore, the distal tip of the balloon guiding catheter cannot be placed outside the petrous segment. Excessive rigidity means the catheter's flexibility is insufficient to track the tortuosity of the distal ICA and other target vessels where clots may reside, and the likelihood of vascular damage or perforation is high.

[0224] Ideally, the tip of the balloon guiding catheter should be as close as possible to the clot. This reduces the distance the clot must be dragged from the target vessel to the tip of the balloon guiding catheter. Since the catheter tip can now engage the clot, it also allows the physician to directly aspirate the clot locally.

[0225] In some scenarios, clots are aspirated remotely using a balloon-guided catheter while the balloon is inflating. Remote aspiration is a procedure that aspirates clots without bringing the catheter tip into contact with the clot. This is particularly effective in closed systems where there is no alternative flow path. The success of this technique is often limited by the fact that the distance between the catheter tip and the clot can be considerable.

[0226] Balloon catheters, whether used for PTA or embolization protection, typically have a double-lumen, double-layered structure along the proximal side of the balloon. This ensures two chambers: one for guiding the wire, catheter, or fluid through, and the other for expansion of the other chamber. This double-layered structure is not always as flexible as desired and is prone to twisting.

[0227] Therefore, there is a need for a balloon guiding catheter that can stop flow and also incorporate a very flexible distal portion that can be traced through tortuous blood vessels (e.g., distal ICA or up to MI or other vascular systems).

[0228] In one embodiment, an axis or segment with enhanced flexibility compared to the proximal segment is present distal to the balloon of the balloon catheter. This flexible segment allows the balloon tip to be positioned more distally within the vascular system. This segment enhancing flexibility can be of the type, corrugated structure, or other design described in U.S. Application No. 15 / 647763, filed July 12, 2017, entitled “HIGH FLEXIBILITY, KINK RESISTANT CATHETER SHAFT,” and U.S. Provisional Application No. 62 / 599560, filed December 15, 2017, entitled “HIGH FLEXIBILITY, KINK RESISTANT CATHETER SHAFT,” both included in the appendices.

[0229] The device can be designed such that the distal end is flexible enough to reach and contact the clot for vacuum suction. Components distal to the flow restrictor (such as a balloon) include at least some of a distal portion and preferably a transition portion. Some transition portions may also be present proximally to the flow restrictor.

[0230] The length of this flexible segment can be varied to allow it to reach specific anatomical locations, such as the distal internal carotid artery, the terminal portion of the internal carotid artery, proximal MI, distal MI, proximal M2, distal M2, basal or vertebral vessels. This length also helps ensure that the balloon does not traverse the cavernous or petrous segments of the ICA while the catheter tip reaches the target vessel. Balloon inflation beyond these segments can lead to vascular injury. The length of the flexible segment can be between 1 cm and 20 cm, preferably between 3 cm and 15 cm.

[0231] The outer diameter of the flexible tip can differ from the outer diameter of the proximal segment of the catheter. In one embodiment, the diameter of the distal segment is larger than that of the proximal segment. In another embodiment, the outer diameter is smaller than that of the proximal segment of the catheter. Variations in diameter, such as those of the distal segment, can also be used. Distal segments with different diameters can help ensure that the balloon is positioned within a specific blood vessel beyond the designated area.

[0232] Figure 33 A device 350 is shown having a flexible distal catheter tip 1351 extending from a balloon 1352, and a main catheter section 1353 extending from a Y-shaped member 1354 on the proximal side of the device 350. Figure 10 The inner inflation chamber 1360 and the outer inflation chamber 1361 of the balloon 352 are shown.

[0233] In one configuration, the outer layer of the balloon inflatable chamber can have enhanced flexibility, while the inner layer of the balloon inflatable chamber can be constructed of conventional structures, including monolayer materials, woven extrusions, coiled extrusions, or other structures. These layers in Figure 34 The inner layer 1360 and outer layer 1361 are schematically shown. In this way, the propulsionability of the conduit can be maintained by the inner layer, while the outer layer mitigates the compromise in terms of flexibility. Furthermore, this structure helps prevent kinking, as mechanics shows that resistance to kinking decreases as the ratio of the inner diameter to the outer diameter of the tube increases. The use of a reinforced flexible structure for the outer layer, which is traditionally more prone to kinking, would address this issue.

[0234] In another embodiment, the double-layered balloon catheter comprises both an inner and an outer layer of a balloon inflation chamber with a reinforced flexible structure. This would represent an ultra-flexible and torsion-resistant balloon catheter.

[0235] In other configurations, the proximal segment can utilize other structures to inflate the balloon, such as a single-chamber design with an exhaust port and leak-proof seal, a coaxial cavity, or other designs.

[0236] It should be noted that the balloon guiding catheter has a long, distal tip that can reach the clot, and such a balloon guiding catheter can be used as a thrombectomy device as described below:

[0237] Angiography is performed to determine the location of the occlusion and the distance between the petrous or cavernous segment of the carotid artery and the occlusion.

[0238] Choose a balloon catheter with a distal tip length suitable for reaching the clot, while ensuring that the balloon inflation does not localize outside the petrous or cavernous segment of the carotid artery.

[0239] Guide the distal tip of the catheter to the clot;

[0240] Inflate the balloon to stop the flow and minimize alternative flow paths that could reduce suction efficiency;

[0241] A vacuum is applied to the inner chamber of the catheter to aspirate the clot;

[0242] If a clot is collected, another angiography is performed via a balloon guiding catheter or diagnostic catheter;

[0243] Remove the balloon guiding catheter;

[0244] The surgery is complete.

[0245] It can be noted that in the above method, the use of a large-diameter distal end close to the target blood vessel will maximize the possibility of complete clot uptake.

[0246] In yet another embodiment, instead of an additional helical wire support, a simple tubular structure with a corrugated configuration is used, which achieves enhanced tube shaft flexibility and resistance to torsion. The corrugations can be defined as adjacent circular recesses within the tube wall thickness, or as... Figure 35 and Figure 36 The diagram shows a continuous spiral indentation. In these figures, the tip has an outer layer 1400 with corrugations 1401 (…). Figure 35 ) and an outer layer 1450 with shallower ripples to achieve the desired flexibility.

[0247] The device can be designed to have sufficient flexibility at the distal end to reach and contact the clot, thereby enabling vacuum aspiration. Typical target vessels are M1, M2, M3, and the distal ICA.

[0248] The distal tip should be long enough to reach the target vessel, while ensuring that the balloon does not pass through the petrous segment of the internal carotid artery (referred to as C2). This is because vessels and surrounding tissues beyond the petrous segment are susceptible to damage, which could have catastrophic consequences.

[0249] Preferably, the balloon should be positioned within the C1 segment of the carotid artery when inflated. It is also preferred that the balloon be positioned distal to the external carotid artery to ensure effective flow restriction and / or backflow. The length of the flexible segment can be between 1 cm and 20 cm, preferably between 3 cm and 20 cm.

[0250] Figure 37 The left image shows an angiographic image of the external carotid artery, common carotid artery, and internal carotid artery (ICA), including segments C1 and C2. The right image shows the acceptable positioning of balloon 2282 within catheter 2280 proximal to distal segment 2281. The balloon should not inflate beyond segment C2. The distal tip of the catheter should be long enough to reach the clot while ensuring a safe position within or proximal to segment C2 of the ICA.

[0251] Any or all of the implementations described above can be used to improve the transition of stiffness from the proximal portion to the distal portion of the distal tip.

[0252] The proximal shaft must have two functions and at least two chambers; one chamber for balloon inflation, and another main chamber for fluid and device delivery, as well as for aspiration. The flexible tip requires only one chamber and therefore may have a larger chamber than the proximal segment. In one embodiment, the inner diameter of the flexible tip is the same as the inner diameter of the proximal shaft.

[0253] In another embodiment, the proximal and distal shafts have the same outer diameter, and the proximal shaft has two concentric chambers, wherein the diameter of the central chamber is smaller than the diameter of the flexible distal tip, such as... Figure 38 As shown in the diagram, the balloon guiding catheter 2300 has a flexible corrugated distal tip 2302 and a balloon 2301. In this case, the inner diameter of the proximal axis chamber 2303 is smaller than the inner diameter of the flexible corrugated distal tip 2302. The proximal and distal axes have the same outer diameter.

[0254] In another embodiment, the inner diameter of the proximal shaft is the same as the inner diameter of the flexible distal tip. In yet another embodiment, the outer diameter of the distal tip is smaller than the outer diameter of the proximal shaft. The inner diameter of the distal tip may be equal to or smaller than the inner diameter of the proximal shaft. Figure 39 A catheter 1400 is shown having a balloon 2401 and a distal portion 2402, the outer diameter of which is smaller than the outer diameter of the proximal portion 2403.

[0255] In one configuration, the distal end consists of a flexible corrugated section on the distal side and a non-corrugated section on the proximal side. Figure 40 The catheter 1500 shown has a non-corrugated proximal region 2501 with a distal region 2502.

[0256] In a construction, such as Figure 41 As shown, for catheter device 2600, radiopaque markers are present at the distal end of the flexible distal tip. Markers are also present directly on the distal and / or proximal side of the balloon to define the balloon's position. Additional intermediate distal markers may be present within the distal tip to define a proximal region that increases stiffness, which is not suitable for distal placement in the C2 segment of the ICA.

[0257] In one configuration, the balloon catheter is adapted for use via direct access to the carotid artery. In this case, a shorter proximal axis improves ergonomics for the physician. In this configuration, the length of the catheter axis closest to the balloon does not exceed 40 cm, preferably not more than 30 cm.

[0258] Flow restriction via a larger diameter catheter inserted near the occlusion or wedging of the vessel

[0259] Compared to what can be achieved using conventional catheter techniques, the above-described implementation allows physicians to place larger-diameter catheters further distally. However, because the vessel diameter is smaller than the catheter itself, it may not be possible to place a larger catheter in the target vessel. In such cases, a larger catheter can be used to achieve flow restriction.

[0260] In some cases, there are additional vessels running throughout the treatment area. For example, in the case of the anterior cerebral artery, using a balloon-guided catheter placed in the ICA to achieve proximal occlusion does not prevent flow to the target treatment site. This is also a problem in posterior stroke, where there are two important inflow vessels (left and right vertebral arteries), and the target treatment site is the basilar artery or posterior communicating artery.

[0261] In one implementation, the system consists of a "mother" and a "daughter" catheter, wherein significant flow restriction or closure can be achieved by placing or wedging a large-diameter, highly flexible mother catheter into a vessel location close to the target treatment site. The smaller daughter catheter can then pass through the mother catheter to reach the treatment site. In this case, a proximal balloon for flow restriction is unnecessary. Proximity to vessel occlusion will also significantly reduce flow rate without wedging the catheter. Figure 42 As shown, there is a large conduit 2702 and a smaller conduit 2703 for aspirating the clot 2701. The large-diameter, highly flexible conduit can achieve flow cessation at the furthest end.

[0262] In other situations, such as embolization, flow restriction using a larger diameter catheter can also be advantageous. For example, in embolization, embolization of non-target vessels is a major issue, often requiring additional embolization procedures to occlude adjacent non-target vessels. Non-target embolization can lead to non-target vessel occlusion or drug delivery to non-target tissue. This can be avoided by placing the distal end of a larger diameter, highly flexible catheter in the vessel supplying the target area for embolization, causing the catheter tip to wedge. After injection of the embolization, the wedge-like position prevents retrograde embolization, thus preventing non-target embolization. Furthermore, the intravascular pressure gradient reflects the proximal injection pressure, rather than the hemodynamic pressure, allowing the physician complete control over embolization delivery.

[0263] Figure 43 This configuration is shown in catheter 2800 with a distal portion 2801. The left figure illustrates the use of a small catheter that cannot reach the distal target vessel (right vessel) during drug or embolization delivery, resulting in undesirable delivery to a non-target vessel (upper left vessel). The right figure illustrates a method in which a highly flexible, large-diameter catheter is selected to effectively occlude the target vessel, and the large-diameter catheter can be placed outside the non-target vessel, so that embolization delivery occurs only in the target vessel. Preferably, the catheter is wedged into the target vessel.

[0264] Furthermore, the distal nature of the target vessel in embolization procedures means that currently only microcatheters can typically access the vessel. This limits the types of emboli that can be used (e.g., a 018 microcoil might be necessary in cases where a larger 035 coil or plug is preferred, or it might be expected that the particles will become clogging in a microcatheter that is the only one capable of accessing the vessel). The technical success of these procedures (particularly embolization of BPH) is also limited by the inability to place larger support catheters distally.

[0265] Corrugated catheter segments, with or without transitional features, can be used as proximal segments of the catheter to provide flexibility around specific bends, for example, as an entry sheath to provide controlled flexibility around the iliac artery. This configuration can also be incorporated into more flexible urethral stent designs or Foley-type catheters, and for use with flexible endoscopes with corrugated walls.

[0266] This device can be used to stop blood flow before precisely delivering embolic agents to areas of the vascular system, tumors, or organs.

[0267] Suction system with pressure control pump

[0268] Aspiration has been proven safe for retrieving clots from cerebral blood vessels. However, the technique is subject to several limitations. In particular, it is often impossible to retrieve the clot at the target treatment site. This is especially true for harder, larger diameter, and longer clots.

[0269] If the clot is not completely removed, the doctor will attempt to extract the catheter and attached clot from the patient under continuous vacuum. This procedure is risky, very time-consuming, and means the doctor cannot access the target blood vessel.

[0270] If angiography determines that the target area has not been reperfused, additional attempts must be made to retrieve the clot. Typically, up to five attempts are required, known as a pass. On average, two attempts are needed. In 20% to 30% of cases, aspiration fails after multiple attempts, and the physician will switch to using a stent remover (Almandoz et al. 2015; Lapergue et al. 2017; Blanc et al. 2017; Möhlenbruch et al. 2016). This further increases the procedure time and cost.

[0271] When a physician withdraws the catheter proximally toward the entry site (usually the femoral or radial artery), some or all of the clot may rupture. These clot fragments are called emboli. Distal emboli result in poor reperfusion outcomes when evaluated on angiography or other imaging studies. Poor reperfusion is associated with poor patient outcomes according to the TICI classification.

[0272] Another limitation of aspiration techniques is that it's not always possible to guide the catheter tip to the surface of the clot. This is because patients can experience extreme tortuosity, meaning that usually only small-diameter catheters (e.g., microcatheters) can reach the clot. Larger-diameter catheters are known to have a greater potential for aspirating clots, but are often too stiff to be guided to the clot's surface. In such cases, the physician can use a smaller-diameter catheter, but the chances of successfully aspirating the clot are lower.

[0273] Depending on the catheter's inner diameter and the characteristics of the clot (diameter, length, strength / hardness, elasticity, etc.), the amount of clot that can be aspirated into the catheter chamber is limited. At this limit, the catheter can be described as blocked. Larger chamber catheters can attract more clots than smaller chamber catheters without becoming blocked. During aspiration, the limit on the amount of clot that can be aspirated can be reached before a complete vacuum is achieved. This means that applying further vacuum does not necessarily increase the amount of clot aspirated once a certain limit is reached. This is schematically illustrated in Figures 44(a) through 44(e) to show that the catheter tip 3500 is used to attempt to aspirate clot 3501. As shown, aspiration is incomplete. A limitation of existing vacuum technologies (vacuum pumps and syringes) is that the applied vacuum is not engineered to prevent blockage or maximize aspiration efficiency.

[0274] Based on the issues outlined above, it is desirable to be able to retrieve the clot at the target site in a single procedure. This would save time, reduce surgical complexity, and minimize the possibility of clot fragmentation during retrieval.

[0275] A pump is disclosed that is used in conjunction with a catheter, such as those described in any of the embodiments above, to aspirate clots or other substances from blood vessels or other areas of the body. The aspiration device is... Figure 45 The image schematically shows that the suction device has a conduit 3500, a guide 3502, a tubing 3503, and a pump and reservoir assembly 3504.

[0276] This invention utilizes the control and / or variation of vacuum pressure and / or fluid displacement during suction to improve suction efficiency. Variations in pressure and / or fluid displacement at the end of the conduit help achieve the following objectives:

[0277] - To prevent blockage of the catheter;

[0278] - Promotes the softening and deformation of the clot, so that the clot can move through the chamber;

[0279] Pump 3504 can provide negative fluid displacement, thereby reducing pressure (achieving vacuum), or positive displacement, thereby increasing pressure. The pump is connected to a conduit to apply positive or negative pressure to the conduit chamber. The pump incorporates a sensor that measures the pressure within the conduit chamber.

[0280] The magnitude of this pressure can be used to determine whether a vacuum or pressurization signal should be applied to the conduit. Based on the measured pressure, the pump can change direction, thus altering the pressure and fluid displacement.

[0281] exist Figure 46 In one embodiment, illustrated schematically in the form of a state diagram, the pump uses defined upper and lower limits to determine whether to apply a vacuum or pressure. These limits allow the conduit to periodically draw in and, if necessary, expel at least some of the clots. This deformation of the clots improves suction efficiency and prevents blockage of the conduit.

[0282] For ease of illustration, the initial pressure in all figures is defined as 0 in-Hg before the pump is turned on in Figure 47(a). In reality, there is a non-zero pressure due to blood pressure. This may be in the region of 60 to 120 mm-Hg (2.4–4.8 in-Hg).

[0283] During the procedure, the pump will continuously measure the pressure within the catheter chamber. If the pump is disconnected, this measurement will be the arterial pressure. Once the pump is switched on and vacuuming begins, a negative pressure will be measured, as shown in Figure 47(b). In the absence of occlusion or partial occlusion at the catheter tip, this will be the nominal reading, representing the free flow of fluid through the catheter. Once the catheter has advanced and engaged with the clot, an increase in vacuum can be observed, as shown in Figure 47(c).

[0284] Initially, when the pump is turned on, a vacuum is applied so that the conduit can draw in some of the clots, as shown in Figure 47(d). Although further increasing the vacuum will draw in more clots, as shown in Figure 47(e), the efficiency of drawing in more clots is reduced by increasing the vacuum pressure, as shown in Figure 47(f). Therefore, the pump will reverse at a certain lower pressure limit, as shown in Figure 47(g). The lower limit is defined such that during the vacuum period, a portion of the clots has been drawn in, but not so much that the clots will irreversibly clog the conduit. An important aspect is that the lower vacuum limit can be set much higher than a full vacuum pressure of -760 mmHg to prevent the draw in excessively large clots that could clog the conduit. In one embodiment, the lower limit is set between -100 mmHg and -200 mmHg. In another embodiment, the lower limit is set between -200 mmHg and -300 mmHg. In yet another embodiment, the lower limit is set between -400 mmHg and -500 mmHg. In another implementation, the lower limit is set between -600 mmHg and -700 mmHg.

[0285] Now, the direction of fluid displacement from the pump is reversed. During this reversal, the conduit will begin to be pressurized, thereby increasing the measured pressure, as shown in Figure 47(g). As the conduit is pressurized (vacuum reversed), the load applied to take up the clot will decrease, thereby unloading the clot and even allowing some or all of the clot to be pushed distally towards the end of the conduit, as shown in Figure 47(h). During this loading / unloading, the clot is softened and thus becomes more "free" within the conduit.

[0286] The pressure is further increased until a high limit is reached. In one embodiment, this high limit is defined as such that the ingested clots may not be completely expelled from the conduit.

[0287] Additional cycles between the lower and upper limits of the clot (Figs. 47(i) to 47(j)) further soften the clot, enabling a larger amount of clot to be taken up for the same lower vacuum limit (Fig. 47(m)), with the final complete take-up of the clot as shown in Fig. 47(n).

[0288] In one embodiment, the upper limit is negative pressure. In another embodiment, the upper limit may be 0 mmHg. In yet another preferred embodiment, the upper limit is positive pressure (Figures 48(a) to 48(c)).

[0289] In the absence of a pressure signal from the pump, the presence of intravascular blood pressure implies the presence of a force exerted by support material from the distal tip of the catheter towards the pump. In one implementation, an initial blood pressure reading can be obtained before the procedure begins. This reading can be used to calculate the required precise upper limit. Mean blood pressure, systolic pressure, or diastolic pressure can be used. A novel aspect of this pump system is the incorporation of feedback into the pump algorithm to produce a more efficient pressure cycle. That is, the pump's ability to measure conditions within the pump (e.g., pressure or fluid displacement) and to continue or modify pump behavior.

[0290] In one implementation, the applied pressure signal includes an oscillating or “vibrating” signal. A vibration signal means a pulse cycle applied between two pressure limits, as shown in Figures 50(a) and 50(b). This signal provides acute aspiration of the clot to cause deformation and / or breakage, thereby improving transport through the catheter. Another approach is to combine a rate-based cycle of negative and positive pressure signals. An oscillation frequency can be defined that may cause the elastic modulus of the clot to be exceeded, thereby breaking up the clot in the catheter and facilitating easier transport.

[0291] exist Figure 49 The increase in this oscillation is shown in the form of a state diagram.

[0292] In one implementation, a vibration signal can be initiated and sustained for a preset number of cycles. In another implementation, a vibration signal can be used until the pressure returns to normal. In this case, the material in the catheter can flow effectively without significant resistance. In yet another implementation, the vibration signal can be initiated based on a specific pressure indicating catheter occlusion or partial occlusion, and terminated based on the measurement of intracatheter pressure indicating free flow or partial occlusion.

[0293] Although these graphs typically depict pressure in the form of a triangular wave relative to time, it should be noted that this is not the actual situation. These graphs are intended to illustrate the directional change of pressure initiated and controlled by this invention. For example, depending on the characteristics of the flocculant and the pump's start-up or reversal speed, the signal may be more square, sawtooth, or sinusoidal. Furthermore, the resulting pressure-time relationship may not have any repeating units at all.

[0294] In one embodiment, the invention includes both an oscillation or vibration signal in a vacuum and a positive pressure signal. This is schematically illustrated in Figures 51(a) and 51(b). In yet another embodiment, the system may combine vacuum oscillation only.

[0295] Compared to static suction techniques, a defined range of low-pressure and high-pressure limits can improve clot transport efficiency. In one embodiment, a low-pressure limit is preferably specified such that the amount of clots that can be taken up in a single cycle is maximized. In another embodiment, a low-pressure limit is preferably specified such that the amount of clots taken up in a single cycle is not maximized, but rather represents an intermediate state between a small amount of clots taken up and a maximum amount of clots taken up. Actual data will be added experimentally in the future.

[0296] In another implementation, the lower limit can be defined in real time. In one implementation, the change in the rate of pressure change during a vacuum cycle can be used. For example, as a conduit becomes blocked, the vacuum pressure typically increases rapidly. This sudden change in vacuum pressure can be used as a signal to switch the pump direction. Similarly, the upper pressure can be defined based on a sudden change in pressure during a pressurization cycle. In one implementation, this can be defined to identify a condition where the conduit has been unblocked.

[0297] It should be understood that the upper and lower limits can be defined by a combination of pressure change rates, a combination of characteristic pressure values, or a combination of both.

[0298] In another configuration, a flow meter or displacement meter is incorporated. This can be used to define upper and lower limits to establish the direction of the pump (suction or vacuum). In one implementation, the flow meter can detect whether there is no fluid flow, which suggests a blockage in the conduit.

[0299] In another embodiment, the pump can use positive and negative fluid displacement to alternately inject and aspirate the conduit. In one embodiment, the injection-to-aspiration cycle ratio can be between 0.01 and 0.99. Preferably, this ratio is between 0.1 and 0.9, or more preferably between 0.4 and 0.9.

[0300] In one configuration, the pump is a sterile unit that can be used in a sterile area or on a patient table adjacent to the patient. This allows physicians to perform all procedures without the need for technicians outside the sterile area. The unit can be disposable or reusable.

[0301] In one configuration, the pump incorporates a peristaltic pump mechanism. This ensures that no blood comes into contact with the pump components. The pump can be combined with a reservoir for collecting the aspirated material. Figures 53(a) and 53(b) illustrate the pump and its components. The housing connecting tubing, on / off switch, battery pack, pulsating pump, and motherboard are shown. A pressure sensor is connected to a lumen chamber, which in turn connects to a catheter, thereby allowing the measurement of pressure within the catheter.

[0302] In one implementation, the pump incorporates a series of LEDs or indicators. These are designed to provide feedback to the physician based on the interaction between the catheter tip and the clot. This is provided by the pressure within the catheter. For example, pressure ranges associated with free flow, partial occlusion, complete occlusion, aspiration, or blockage within the catheter.

[0303] In addition, the indicator can be used to show the doctor that the pump is oscillating or vibrating.

[0304] A method is disclosed in which physicians use feedback from indicators to limit the required adjustments at the catheter tip.

[0305] Place the catheter tip close to the clot. Turn on the pump. If the pump indicates free flow is observed, the catheter should be moved distally to further engage the clot. If the catheter is aspirated in cases of partial or complete occlusion, the physician will wait until the pump is free flow again. The physician will then move the catheter tip distally again to engage the next clot. This allows for the clearing of clots throughout the vessel. If the pump becomes blocked, signal to the physician that conventional catheter aspiration techniques may be appropriate.

[0306] The embodiments described in this application are generally designed to enable physicians to access areas of the body with challenging anatomy using highly flexible, corrugated catheters. Catheter design is optimized through transitions and additional components such as flow restrictors and high-efficiency pumps. The ability to manufacture larger catheters while maintaining this type of controlled flexibility can improve treatment methods, such as clot removal and embolization delivery into the body.

[0307] The present invention is not limited to the described embodiments, but may vary in structure and details.

Claims

1. A catheter (1) comprising a sheath, the sheath comprising an inner liner and an outer tubular layer, the inner liner defining a lumen, and the outer tubular layer comprising helical supports in the sheath material along at least some of the length of the sheath, the catheter comprising at least a proximal portion (2) and a distal portion (3), the outer tubular layer having a corrugated outer surface (15) with corrugations along at least some of the length of the distal portion, wherein, A helical support is encapsulated between the corrugations and the outside of the inner liner; It is characterized in that, The inner liner comprises an ePTFE tubular layer (1207) in the distal portion and a PTFE tubular layer (1208) in the proximal portion, and a transition section in which the ePTFE tubular layer and the PTFE tubular layer contact without overlapping, or through a lap joint in which the ePTFE tubular layer and the PTFE tubular layer are concentric.

2. The catheter of claim 1, wherein, The inner liner has a thickness between 0.025 mm and 0.3 mm.

3. The catheter of claim 1 or 2, wherein, In the lap joint, the length of the overlapping portion of the PTFE tubular layer with the ePTFE tubular layer is between 1 mm and 30 mm.

4. The catheter of claim 1 or 2, wherein, The transition section is between 5 cm and 30 cm from the distal end of the catheter.

5. The catheter of claim 4, wherein, The transition section is at least 10 cm from the distal end.

6. The catheter of claim 1 or 2, wherein, The transition section is present in a region close to the region of the catheter having the corrugations.

7. The catheter of claim 1 or 2, wherein, In the distal portion, the width of the corrugations is at least 60% of the thickness of the sheath and the depth of the corrugations is at least 70% of the thickness of the sheath.

8. The catheter of claim 1 or 2, wherein, In at least one region of the catheter, the depth of the corrugations is between 5% and 95% of the thickness of the sheath.

9. The catheter of claim 1 or 2, wherein, The corrugations are imprints produced by winding a round helical tether wire on the sheath material during manufacturing.

10. The catheter of claim 1 or 2, wherein, The corrugations are imprints produced by winding a round helical tether wire on the sheath material during manufacturing from a depth and width that do not produce imprints to a depth of at least 50% of the thickness of the sheath.

11. The catheter of claim 1 or 2, wherein, The corrugations are imprints produced by winding a round helical tether wire on the sheath material during manufacturing from a depth and width that do not produce imprints to a depth of at least 70% of the thickness of the sheath.

12. The catheter of claim 1 or 2, wherein, The corrugations are imprints produced by winding a round helical tether wire on the sheath material during manufacturing from a depth and width that do not produce imprints to a depth of at least 95% of the thickness of the sheath.

13. The catheter of claim 1 or 2, wherein, Over at least some of the length of the catheter, the width of the corrugations is between 20% and 45% of the pitch of the corrugations.

14. The catheter of claim 1 or 2, wherein, At the distal most region of the distal portion, the width of the corrugations is at least 60% of the thickness of the sheath.

15. The catheter of claim 1 or 2, wherein, At the distal most region of the distal portion, the depth of the corrugations is at least 70% of the thickness of the sheath.

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