Delivery catheter with backflow prevention obturator and stretch prevention feature

Abstract

Delivery catheters for occluding aneurysms include a catheter tube extending a length. In some configurations, the catheter can include a reflux occluder section having a third diameter that is greater than a first diameter and a second diameter. The reflux occluder section is disposed along the length of the catheter tube between a proximal portion and a distal portion. Certain implementations of the catheter can include an inflatable section including a collapsed configuration having a first diameter and an inflated configuration having a second diameter sized to prevent reflux of glue within the blood vessel proximal of the inflatable section. Configurations of the catheter can include a circulation pump to create a column of fluid positioned proximate the distal end between the distal end and the glue to prevent reflux of the glue proximal of the distal end.

Description

[0001] Cross-references to related applications This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 548,004, filed November 10, 2023, and U.S. Provisional Patent Application No. 63 / 548,006, filed November 10, 2023. The entire contents of each of these patent applications are incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to devices and methods for delivering embolic gel or other fluid embolic agents to a treatment site. More specifically, this disclosure relates to catheters having an anti-backflow occlusion section, catheters having tensile strength features, and / or catheters having a circulating pulse to prevent backflow. Background Technology

[0003] Some vascular procedures require embolization of blood vessels to prevent blood from flowing to specific areas of the body. In neurovascular procedures, such embolization may involve placing an embolic device or material in a target vessel to block blood flow to, for example, an aortic aneurysm, an arteriovenous malformation (AVM), a chronic subdural hematoma (CSDH), or other malformations. Precise placement of the embolic device or material is crucial to prevent unintended migration, which can lead to serious problems, including stroke if a non-target vessel is occluded.

[0004] One method of embolizing a target vessel is to deliver a fluid embolic agent, such as cyanoacrylate glue (e.g., n-butyl cyanoacrylate (NBCA)), to the target vessel. These types of glue polymerize upon contact with blood, thereby blocking flow and creating a flexible embolism. As mentioned above, ensuring that the glue is delivered to the precise target site and remains there is crucial for the procedure. Problems can arise when the cyanoacrylate glue refluxes proximal to the delivery catheter. This can cause the glue to migrate into non-target areas of the vascular system and may also make removal of the delivery catheter difficult. Even if the glue does not reflux through the delivery catheter, there is still a risk of glue polymerization and the distal end of the catheter becoming lodged in the glue, making catheter retrieval more difficult after embolization. These and other problems exist. Summary of the Invention

[0005] The purpose of this design is to provide an apparatus and method for overcoming the aforementioned problems. One aspect of this disclosure provides a delivery catheter. The proximal portion of the catheter conduit may have a first diameter, and the distal portion of the catheter conduit may have a second diameter. The delivery catheter may include a reflux occluder section having a third diameter greater than the first and second diameters. This reflux occluder section may be disposed along the length of the catheter conduit between the proximal and distal portions.

[0006] The first diameter of the catheter conduit may be larger than the second diameter of the catheter conduit. The reflux occluder segment may be a protrusion in the catheter conduit. The reflux occluder segment may be compressible for insertion into a blood vessel and may expand to a third diameter. The catheter conduit may include a braid extending along its length. The distal end of the braid may be positioned within the proximal portion of the catheter conduit. The distal end of the braid may be positioned within the reflux occluder segment. The distal end of the braid may be positioned within the distal portion of the catheter conduit. The distal end of the braid may include a braid attachment. The braid attachment may be a loop with an atraumatic distal end. The braid attachment may contain a radiopaque material.

[0007] The backflow occluder section may be one or more baffles extending from the conduit. These baffles may include helical baffles spirally arranged about the longitudinal axis of the delivery conduit. The one or more baffles may include a first helical baffle and a second helical baffle radially offset from the first helical baffle. The one or more baffles may include an annular baffle extending radially from the conduit. These one or more baffles may include a first annular baffle having a first baffle diameter and a second annular baffle having a second baffle diameter. The first baffle diameter may be smaller than the second baffle diameter.

[0008] The catheter conduit may include a braided material extending along the length of the catheter conduit. The third diameter may be smaller than the diameter of the target blood vessel.

[0009] One aspect of this disclosure provides a delivery catheter. The delivery catheter may include a catheter conduit extending a length and including a braid extending along the length of the catheter conduit. The delivery catheter may include a reflux occluder section disposed along the length of the catheter conduit between a proximal and a distal portion of the catheter conduit, wherein a distal end of the braid is positioned within the reflux occluder section. The catheter conduit may include axial fibers.

[0010] One aspect of this disclosure provides a method. The method may include positioning a reflux occluder segment proximally to a target site, such that the reflux occluder segment extends radially from the catheter conduit of a delivery catheter and contacts the vessel wall near the target site. The method may include delivering adhesive through the catheter conduit. The method may include restricting adhesive flow proximally to the reflux occluder segment via the reflux occluder segment. The method may include withdrawing the delivery catheter from the main vessel. The reflux occluder segment may have an occluder diameter larger than the proximal diameter of the proximal portion of the catheter conduit, and the occluder diameter may be larger than a third diameter of the distal portion of the catheter conduit.

[0011] Another aspect of this disclosure provides a delivery catheter. The delivery catheter includes a catheter conduit of a certain length. The delivery catheter includes a non-inflatable segment positioned along its length. The delivery catheter includes an inflatable segment disposed distal to the non-inflatable segment along its length. The delivery catheter includes a restrictor disposed within the lumen of the catheter conduit distal to the inflatable segment. The inflatable segment includes a collapse configuration having a first diameter and an expansion configuration having a second diameter. The second diameter is sized to restrict backflow of fluid embolic agent proximal to the inflatable segment within the blood vessel. The catheter conduit, the non-inflatable segment, and the inflatable segment share a single lumen.

[0012] Another aspect of this disclosure provides a delivery catheter. The delivery catheter includes a catheter conduit of a certain length. The delivery catheter includes an expandable segment positioned along its length. The expandable segment includes a fixed proximal collar and a membrane having an open end. The expandable segment includes a collapse configuration having a first diameter and an expansion configuration having a second diameter. The second diameter is sized to restrict the backflow of fluid embolic agents proximal to the expandable segment within the blood vessel.

[0013] Another aspect of this disclosure provides a delivery catheter. The delivery catheter includes a catheter conduit having a distal end. The delivery catheter includes a drug conduit in fluid communication with the distal end of the catheter conduit. The delivery catheter includes a drug pump to drive a fluid embolic agent through the drug conduit. The delivery catheter includes a fluid conduit in fluid communication with the distal end of the catheter conduit. The delivery catheter includes a circulation pump to drive a second fluid to the distal end of the catheter conduit via circulating pulses. The circulating pulses generate a fluid column positioned near the distal end between the distal end and the fluid embolic agent to limit proximal backflow of the fluid embolic agent at the distal end. The second fluid is a different material from the fluid embolic agent.

[0014] Other aspects of this disclosure will become apparent after viewing the following detailed description in conjunction with the accompanying drawings. As will be understood and appreciated by those skilled in the art, additional features or manufacturing and usage steps may be included. Attached Figure Description

[0015] The foregoing and other aspects of this disclosure will be further discussed with reference to the following description and in conjunction with the accompanying drawings, in which similar numbers indicate similar structural elements and features in various figures. The drawings are not necessarily drawn to scale, but rather focus on illustrating the principles of this disclosure. The drawings depict one or more specific embodiments of the apparatus of the invention by way of example only and not by way of limitation. It is anticipated that those skilled in the art will be able to conceive of and combine elements from the various drawings to better meet the needs of the user.

[0016] Figure 1 This is a diagram of a delivery catheter being advanced through a vascular system according to various aspects of this disclosure; Figure 2A This is a side view of a delivery conduit having a backflow occluder section and a braid extending proximal to the backflow occluder section, according to various aspects of this disclosure. Figure 2B This is a side view of a delivery conduit having a backflow occluder section and a braid extending to the backflow occluder section, according to various aspects of this disclosure. Figure 2C This is a side view of a delivery conduit having a backflow occluder section and a braid extending distal to the backflow occluder section, according to various aspects of this disclosure. Figure 3A This is a perspective view of a delivery conduit having a backflow occluder section with a spiral baffle, according to various aspects of this disclosure. Figure 3B This is a perspective view of a delivery conduit having a backflow occluder section with an annular baffle, according to various aspects of this disclosure. Figure 3C Based on all aspects of this disclosure Figure 3B A cross-sectional view of the reflux occluder section of the delivery catheter; Figure 4 This is a perspective view of a delivery catheter having proximal braid and axial fibers according to aspects of this disclosure; Figure 5 This is a flowchart illustrating an example method of using a delivery catheter according to various aspects of this disclosure; Figure 6 This is a diagram of another example of a delivery catheter being advanced through a vascular system according to various aspects of this disclosure; Figure 7A It is based on various aspects of this disclosure and has expandable sections. Figure 6 A side sectional view of an exemplary delivery catheter; Figure 7B Based on all aspects of this disclosure Figure 7A End view of the delivery catheter.

[0017] Figure 7C Based on all aspects of this disclosure Figure 7A A side view of the delivery catheter, in which the expandable section expands; Figure 8A This is a side view of a delivery catheter having an umbrella-shaped expandable section according to various aspects of this disclosure; Figure 8B Based on all aspects of this disclosure Figure 8A A side view of the delivery catheter, in which the expandable section expands; Figure 8C Based on all aspects of this disclosure Figure 8B A radial cross-sectional view of the delivery catheter along line 8B-8B; Figure 8D This is a side view of another delivery conduit having an umbrella-shaped expandable section according to various aspects of this disclosure, the umbrella-shaped expandable section having a frame having an open end, the expandable section being in an expandable configuration. Figure 8E Based on all aspects of this disclosure Figure 8D A radial cross-sectional view of the delivery catheter along line 8E-8E; Figure 8F Based on all aspects of this disclosure Figure 8D A side view of the delivery conduit, in which the expandable portion is in a collapsed configuration; Figure 8G This is an example frame for an umbrella-shaped expandable section according to various aspects of this disclosure; and Figures 9A to 9E This is a side view of a conduit that utilizes a fluid column to prevent backflow of fluid embolic agents according to various aspects of this disclosure. Figure 9A This is a side view of the catheter; Figure 9B This is a side view of the catheter for injecting fluid embolizing agent; Figure 9C This is a side view of the conduit from which the fluid column is discharged; Figure 9D This is a side view of the catheter, where the fluid column is interrupted; and Figure 9E This is a side view of a conduit having a port that allows fluid to exit the conduit proximally at the distal end of the conduit. Detailed Implementation

[0018] Specific examples of this disclosure will now be described in detail with reference to the accompanying drawings, wherein like reference numerals denote functionally similar or identical elements. These examples address many of the shortcomings associated with conventional clot retrieval aspiration catheters, such as the inability to properly or accurately deploy to the target site and ineffective clot removal.

[0019] This design addresses catheters used in embolization procedures that employ adhesives (such as butyl cyanoacrylate (NBCA) or other cyanoacrylate adhesives), other liquid embolic agents (such as copolymers like Onyx, Squid, and PHIL), or other particles to occlude blood vessels. This design offers several advantages over previous catheter designs. For example, a typical rubber or non-rubber catheter can simply be a cylindrical tube extending along its length. While such catheters can be inserted into the treatment site to deliver the embolic adhesive, problems exist. First, existing catheters have poor maneuverability and are prone to stretching and breakage if the tip becomes stuck in the polymerized adhesive. Furthermore, because previous catheter systems were simply cylindrical tubes, there was nothing in this design to prevent backflow of the adhesive along the catheter's length. The design described herein provides improvements to the catheter system to mitigate problems with maneuverability, retraction, and / or backflow.

[0020] Access to various intravascular vessels (whether coronary, pulmonary, or cerebral) involves well-known procedural procedures and the use of many routinely available commercially available accessory products. These products, such as angiographic materials, mechanical thrombectomy devices, microcatheters, and guidewires, are widely used in laboratory and medical procedures. Their function and exact construction are not described in detail when used in conjunction with the devices described below. While this specification is presented in many cases within the context of intracranial artery thrombectomy, this disclosure is also applicable to other procedures and other bodily pathways.

[0021] Switch to the attached image. Figure 1 A possible sequence of approaches to a target site 16 via a delivery catheter 100 through a main vessel 10 is illustrated. In the example shown, the target site 16 is one or more vascular branches distal to a non-target site 14, meaning that occlusion at the location of the distal end of the delivery catheter 100 will prevent blood flow proximal to that site. In this example, the target site 16 shows another vascular branch, so that branch will be unaffected by occlusion distal to that site. The delivery catheter 100 may include a highly flexible catheter conduit 120, enabling it to navigate M1 or other tortuous areas of the neurovascular system to reach the vicinity of the target site 16. As will be described in more detail herein, the delivery catheter 100 may include a backflow occluder segment 102 having a diameter that helps to limit or prevent backflow of adhesives that can be delivered via the catheter. Any reference to “adhesive” in this disclosure is not limiting, as the delivery catheters described herein can prevent backflow of many types of fluid embolic agents. Therefore, fluid embolizing agents may include adhesives (such as butyl cyanoacrylate (NBCA) or other cyanoacrylate adhesives), other agents (such as copolymers (such as Onyx, Squid, and PHIL)), or other particles for occluding blood vessels. Therefore, when the term "adhesive" is used herein, it should be understood that other fluid embolizing agents may be used in place of "adhesive." In some examples, the reflux occluder segment 102 may contact the vessel wall 12 to limit the backflow of adhesive near the reflux occluder segment 102. It is also conceivable that, since the adhesive may be more viscous than other fluids at the target site, complete peripheral contact may not be necessary to limit the backflow of adhesive proximal to the reflux occluder segment 102, so the diameter of the reflux occluder segment 102 may be slightly smaller than the diameter of the blood vessel in that region.

[0022] Figures 2A to 2C A delivery catheter 100 with a reflux occluder section 102 is depicted, which is a protrusion 202 in the catheter conduit 120. For illustrative purposes, the delivery catheter 100 may be considered to have a length of 500, which includes a proximal portion 220 near the reflux occluder section 102 and a distal portion 240 far from the reflux occluder section 102. Figures 2A to 2CThe delivery catheter 100 shown illustrates an example where the proximal portion 220 has a proximal diameter 800 larger than the distal diameter 810 of the distal portion 240; and the reflux occluder segment 102 has a diameter 820 larger than both the proximal diameter 800 and the distal diameter 810 (i.e., the protrusion 202). By having a conduit with a larger diameter in the proximal portion 220 than in the distal portion 240, the distal portion 240 can act as a bottleneck for the adhesive flowing through the lumen 114 of the delivery catheter 100. This bottleneck can generate positive pressure within the reflux occluder segment 102 as the adhesive is pushed through the catheter, thereby allowing the reflux occluder segment 102 to expand to contact the vessel wall 12 (see [link to documentation]). Figure 1 In other examples, the proximal diameter 800 and the distal diameter 810 can be the same diameter.

[0023] Figures 2A to 2C Another feature of the delivery catheter 100 shown is that the reflux occluder section 102 (i.e., the protrusion 202) may be formed with only a single lumen 114, which extends along the length 500 of the catheter through each of the proximal portion 220, the reflux occluder section 102, and the distal portion 240. This is in contrast to conventional balloon catheters, which have multiple lumens, one for inflating the balloon and another for delivering the instrument distal to the balloon. Figures 2A to 2C In the example shown, a separate lumen is not required because lumen 114 is used to deliver the glue to the distal end 110 of the delivery catheter 100. In some examples, the protrusion 202 can be made with low radial force so that it can collapse if advanced into a vessel slightly smaller than its diameter 820. The internal pressure of the glue injection prevents the collapseable protrusion 202 from collapsing under the external pressure of the glue, which may attempt to return proximally to the reflux occluder segment 102. This is Figures 2A to 2C Another advantage of the system shown is that it surpasses traditional balloon catheters because the delivered material generates positive pressure that prevents the same material from flowing back proximally.

[0024] Now for specific reference Figure 2AThe figure illustrates an example delivery catheter 100 with a reflux occluder section 102 having a braid 104 extending proximally to the reflux occluder section 102. The braid 104 can provide axial strength to the catheter conduit 120 to increase its maneuverability through the vascular system. The braid 104 can be made of a reinforcing material such as metal wire (e.g., stainless steel, nitinol, etc.), para-aramid, glass fiber, carbon fiber, etc. The distal end 112 of the braid 104 can include a braid attachment 106, which can be a loop surrounding the catheter conduit 120 to securely attach the braid 104 to the conduit and provide automatic contouring at the end of the braid 104. In some cases, the braided attachment 106 may contain a radiopaque material that allows an operator (such as a physician) to determine, via radiography, where the proximal end of the reflux occluder segment 102 is located within the vascular system. The radiopaque material may include high-density materials such as gold or platinum.

[0025] Figure 2B This is a side view of a delivery conduit 100 with a backflow occluder section 102, wherein a braid 104 extends into the backflow occluder section 102. The braid 104 may be substantially similar to that described above for... Figure 2A The braided fabric, but the distal end 112 of the braided fabric is positioned within the region of the protrusion 202. The braided fabric 104 may terminate within the region of the protrusion 202 as shown. The delivery conduit 100 may include a braided fabric attachment 106, which may also act as a means to prevent the protrusion 202 from expanding beyond a predetermined diameter under the internal pressure of the glue injection (e.g., Figure 2A The component shown has a diameter of 820 (as shown). In other examples, Figures 2A to 2C Any of the examples shown may additionally or alternatively include another expansion-limiting feature, such as fibers embedded in the wall of the protrusion 202. In some cases, the woven attachment 106 may contain a radiopaque material that allows an operator (such as a physician) to determine, by radiography, where the protrusion 202 of the reflux occluder segment 102 is located within the vascular system.

[0026] Figure 2C This is a side view of a delivery conduit 100 having a reflux occluder section 102, wherein a braid 104 extends distally to the reflux occluder section 102. The braid 104 may be substantially similar to that described above for... Figure 2A and Figure 2B The braided fabric, but the distal end 112 of the braided fabric 104 is positioned distal to the protrusion 202. The braided fabric material can serve to prevent the protrusion 202 from expanding beyond a predetermined diameter under the internal pressure of the glue injection (e.g., Figure 2AThe component shown has a diameter of 820 mm. In some cases, the braided attachment 106 may contain a radiopaque material that allows an operator (such as a physician) to determine, via radiography, where the distal end of the reflux occluder segment 102 is located within the vascular system. In some examples, the braid 104 may extend close to the distal end 110 of the reflux occluder segment 102, thereby allowing an operator to determine, via radiography, where the distal end of the delivery catheter 100 is located within the vascular system.

[0027] Figures 3A to 3C A delivery conduit 100 is depicted having a reflux occluder section 102 including one or more baffles. Figures 3A to 3C The delivery catheter 100 in the example shown has a length of 500, which includes a proximal portion 220 near the reflux occluder section 102 and a distal portion 240 distal to the reflux occluder section 102. Similar to the protrusion 202 described above, when at the target site 16 (see...) Figure 1 When applying adhesive to the proximal side of the reflux blocker section 102, the baffle of the reflux blocker section 102 can also limit or prevent the adhesive from flowing back to the proximal side of the reflux blocker section 102.

[0028] For details, please refer to the following: Figure 3A The reflux occluder section 102 may include one or more helical baffles 306 that are helical about the longitudinal axis 550 of the delivery catheter 100. One or more helical baffles 306 extend laterally from the catheter conduit 120 and proximity to the vessel wall 12 (see [link to original text]). Figure 1 The spiral baffle 306 not only restricts or prevents backflow proximal to the reflux occluder segment 102, but also helps to center the distal end 110 of the catheter within the relevant vessel.

[0029] In some cases, the backflow occluder section 102 may have a single helical baffle, for example, a first helical baffle 302 that helices around the longitudinal axis 550 of the delivery conduit 100. In other examples, the backflow occluder section 102 includes a second helical baffle 304 that is radially offset from the first helical baffle 302, such as... Figure 3A As shown. The first helical baffle 302 and the second helical baffle 304 are collectively referred to herein as helical baffle 306. This example with two separate helical baffles 306 can create a greater contact area on the vessel wall 12 (see...). Figure 1 The helical baffle 306 may be formed of the same material as the catheter conduit 120. In other examples, the helical baffle 306 may be made of a more flexible and resilient material than the catheter conduit 120 in order to provide improved surface contact with the associated vessel wall 12.

[0030] Now for reference Figure 3B and Figure 3C The backflow occluder section 102 may include one or more annular baffles 314 extending radially from the conduit 120. The annular baffles 314 operate in a manner similar to the protrusions 202 and the spiral baffles 306 described above, as they can limit or prevent backflow of adhesive on the proximal side of the backflow occluder section 102. The one or more annular baffles 314 may include a first annular baffle 308 having a first baffle diameter 830 and a second annular baffle 310 having a second baffle diameter 840. The first annular baffle 308 and the second annular baffle 310 are collectively referred to herein as annular baffles 314, and for clarity, the first annular baffle 308 may be considered as... Figure 3C The farthest side baffle in the middle.

[0031] like Figure 3C As shown in the cross-section, the diameter 830 of the first baffle can be smaller than the diameter 840 of the second baffle. In other words, the diameter of the annular baffle 314 increases as it moves from the distal end to the proximal end within the reflux occluder section 102. This change in diameter helps accommodate target vessels with different diameters. Furthermore, the smaller diameter 830 allows the adhesive to flow around the baffle in the larger vessel, while the adhesive cannot flow around the larger diameter 840. Therefore, excess adhesive can be trapped between the first annular baffle 308 and the second annular baffle 310, allowing excess adhesive to be withdrawn when the delivery catheter 100 is retracted from the vessel. Figure 3B and Figure 3C As shown, the annular baffle 314 may also have the following configuration: the farthest annular baffle (e.g., the first annular baffle 308) has a small diameter, the most central annular baffle (e.g., the second annular baffle 310) has a large diameter, and then the annular baffle gradually tapers downwards again, such that the nearest annular baffle (e.g., Figure 3C The third annular baffle (312) also has a smaller diameter. Of course, there can be more than three annular baffles. Figure 3B and Figure 3C The image shown illustrates six annular baffles, but additional annular baffles can be combined with them.

[0032] Figure 4 This is a perspective view of a delivery catheter 100, which has a proximal braid 104 and axial fibers 402 extending along a length 500 of the catheter conduit 120, although... Figure 4 The example shown does not have the large backflow blocker section as shown in the previous figure, but Figure 4 The braid 104 and axial fiber 402 shown can be applied to any of the examples in the preceding examples. As mentioned above, if the distal end of the conduit becomes stuck in the polymer, that end is prone to stretching and breaking. Figure 4The example delivery catheter 100 provides improved retractability by including an axial fiber 402 that extends or fully extends from the distal end 110 of the catheter conduit 120. The axial fiber 402 can be a material with higher tensile strength than the catheter conduit 120, allowing the catheter conduit 120 to be flexible but also resistant to stretching when pulled proximally to retract from the vessel. The axial fiber 402 can comprise liquid crystal polymer (LCP), polyethylene naphthalate (PEN), ultra-high molecular weight polyethylene (UHMWPE), para-aramid, glass fiber, metal wire (e.g., stainless steel, nitinol, etc.), directionally expanded polytetrafluoroethylene (ePTFE), etc.

[0033] exist Figure 4 In another embodiment of the catheter shown, catheter 100 includes an inner liner 602 made of highly oriented polytetrafluoroethylene (PTFE) and an outer polymer sheath 604. The orientation of the polymer chains in the PTFE liner makes the axial stiffness (or elongation) of the PTFE liner significantly greater than that of the outer polymer sheath 604, eliminating the need for axial fibers to provide tensile strength to the catheter. The encapsulated PTFE liner is an example of such a liner material. Specifically, the preferred inner liner 602 has an elastic modulus greater than 1,000 MPa (N / mm²), and preferably greater than 1,500 MPa, and most preferably close to or greater than 2,000 MPa. Because the inner liner 602 can be made with very thin walls and is located inside the catheter 100, its negative impact on the lateral flexibility of the catheter 100 can be minimized. The outer catheter sheath 604 has a large diameter and wall thickness, and is therefore geometrically configured to have a large area quadratic moment. However, because the outer sheath 604 can be made of a polymer with a much lower elastic modulus than the inner liner 602, its contribution to the axial and lateral stiffness of the catheter is reduced. Specifically, the elastic modulus of the preferred outer sheath 604 is less than 10% of the elastic modulus of the inner liner 602, and preferably, it is close to or less than 1% of the elastic modulus of the inner liner 602. A significant advantage of this construction is that the resulting catheter is extremely flexible and also very tensile-resistant, so that if the distal end 110 becomes lodged in the vessel 10 after embolization, it can be safely pulled out without the risk of the catheter 100 breaking and remaining partially in the patient's body.

[0034] The liner 602 described above can be used in any design of the catheter 100 disclosed herein to provide advantages similar to those described above. In some embodiments, the liner may extend to the very tip of the catheter, while in other embodiments, the liner 602 may stop before the catheter tip. For example, in Figure 1 In the catheter described in Figure 2, the liner 602 may stop at or just near the expanded reflux occluder section 102.

[0035] As described throughout this disclosure, the delivery catheter 100 may include a proximal portion 220 and a distal portion 240. In some embodiments, the braid 104 may be provided only on the proximal portion 220 to increase maneuverability. The distal portion 240 may be without the braid 104 to allow the distal end of the delivery catheter 100 to reach the tortuous distal regions of the neurovascular system softly, flexibly, and non-invasively. Furthermore, the pressure of the embolic injection may be lower at the distal end of the delivery catheter 100 (e.g., toward the distal end 110), resulting in less need for reinforcement in that distal segment. However, the braid 104 may also extend all the way to the distal portion 240. In some cases, the braid 104 may extend to the distal end 110. The ends of the axial fibers 402 may be secured to the catheter conduit 120 via attachments (e.g., the aforementioned braid attachment 106). The braided attachment 106 may contain a radiopaque material that allows an operator (such as a physician) to determine via radiography where the distal end (e.g., distal tip 110) is located within the vascular system. The radiopaque material may include a high-density material such as gold or platinum. The delivery catheter 100 may additionally or alternatively include a separate radiopaque marker 108 near the distal tip 110 of the catheter conduit 120.

[0036] Figure 5 This is a flowchart illustrating an example method 900 of using the delivery catheter 100 according to various aspects of this disclosure. Method 900 includes advancing 902 of the distal end 110 of the delivery catheter 100 through the main vessel 10 to a position distal to a non-target site 14 and proximal to a target site 16. This step may be assisted by a braided attachment 106 at the end of the braid 104 (for the delivery catheter 100 including the braid 104), and / or by a separate radiopaque marker 108 positioned near the distal end 110 of the delivery catheter 100.

[0037] Method 900 includes positioning a reflux occluder segment 102 904 proximally to a target site 16 such that the reflux occluder segment 102 extends radially from the catheter conduit 120 of the delivery catheter 100 and contacts at least a portion of the vessel wall 12 near the target site 16. The reflux occluder segment 102 may have an occluder diameter 820 that is larger than the proximal diameter 800 of the proximal portion 220 of the catheter conduit 120 and larger than the distal diameter 810 of the distal portion 240 of the catheter conduit 120.

[0038] Method 900 includes delivering a fluid embolic agent 906 through catheter conduit 120. Method 900 includes restricting the proximal backflow of the fluid embolic agent 908 via a backflow occluder segment 102. Method 900 includes withdrawing the delivery catheter 100 from the main vessel 10 910. If the delivery catheter 100 includes axial fibers 402, the withdrawal step 910 may further include preventing axial stretching of the catheter conduit 120.

[0039] The specific examples described below address many of the drawbacks associated with conventional clot retrieval aspiration catheters, such as poor or inaccurate deployment to the target site and ineffective clot removal.

[0040] Figure 6 A possible sequence for approaching a target site 16 via the main vessel 10 using another example delivery catheter 200 is illustrated. In the example shown, the target site 16 is one or more vascular branches distal to a non-target site 14, meaning that occlusion at the distal end of the delivery catheter 200 would prevent blood flow proximal to that site. In this example, the target site 16 shows another vascular branch, so that branch would be unaffected by occlusion distal to that site. The delivery catheter 200 may include a highly flexible catheter conduit 202, enabling it to navigate M1 or other tortuous areas of the neurovascular system to reach the vicinity of the target site 16. As will be described in more detail herein (see, for example...). Figure 7A The delivery catheter 200 may include expandable sections 204, 304 disposed along a length 250 of the catheter 200. In some examples, the expandable sections 204, 304 may contact the vessel wall 12 to prevent or limit backflow of the adhesive near the expandable sections 204, 304. Any reference to “adhesive” in this disclosure is not limiting, as the delivery catheters described herein can prevent backflow of many types of fluid embolizing agents. Thus, fluid embolizing agents may include adhesives (such as n-butyl cyanoacrylate (NBCA) or other cyanoacrylate adhesives), other agents (such as copolymers (such as Onyx, Squid, and PHIL)), or other particles for occluding vessels. Therefore, when the term “adhesive” is used herein, it should be understood that other fluid embolizing agents may be used instead of “adhesive.”

[0041] Figures 7A to 7C A delivery catheter 200 having an expandable section 204 is shown according to various aspects of this disclosure. Figures 7A to 7C The delivery conduit 200 has a length 250 of conduit 202, and the conduit 202 has a non-inflatable section 212 and an inflatable section 204 disposed distal to the non-inflatable section along the length 250. The inflatable section 204 includes a collapse structure having a first diameter 252 (see [link to documentation]). Figure 7A ) and an expansion structure with a second diameter of 254 (see Figure 7C The second diameter 254 is sized to engage the vessel wall 12 and prevent or limit backflow of adhesive proximal to the expandable segment 204 within the vessel 10. The catheter conduit 202, the non-expandable segment 212, and the expandable segment 204 each share a single lumen 210.

[0042] The expandable section 204 comprises an elastomeric material that allows it to stretch outward under positive pressure (e.g., radially from the longitudinal axis 216). To generate positive pressure, the delivery conduit 200 may include a restrictor 206 positioned near the distal end 208 of the conduit 202, and the expandable section 204 may be positioned proximal to the restrictor 206. Figure 7B An end view illustrating the restrictor 206 is provided. The restrictor 206 restricts flow (e.g., fluid embolic agent flow) through the lumen 210, which in turn generates positive pressure at the expandable section 204 to cause the expandable section 204 to expand. In some specific embodiments, the delivery catheter 200 includes a radiopaque strip 214 positioned near the distal end of the delivery catheter 200. In some examples, the radiopaque strip 214 is positioned along the length 250 of the catheter conduit 202 between the expandable section 204 and the restrictor 206, as shown. Figure 7A As shown. In this example, the radiopaque strip 214 allows a user (such as a surgeon) to observe the location of the distal end of the expandable segment 204 under fluoroscopic guidance. Alternatively or additionally, the radiopaque strip 214 may be located distal to the restrictor 206, i.e., closer to the distal end 208. The radiopaque material may include a high-density material, such as gold or platinum. Referring again to the expandable segment 204, this segment may include expansion-limiting features, such as radial fibers 218 embedded in the wall of the catheter conduit 202 at the expandable segment 204. The radial fibers 218 may be a material with a higher tensile strength than the catheter conduit 202, which will prevent the expandable segment 204 from radially expanding beyond a predetermined diameter. The radial fibers 218 may comprise liquid crystal polymers (LCP), polyethylene naphthalate (PEN), ultra-high molecular weight polyethylene (UHMWPE), para-aramid, glass fiber, metal wire (e.g., stainless steel, nickel-titanium, etc.), oriented expanded polytetrafluoroethylene (ePTFE), etc.

[0043] Referring again to the non-inflatable section 212, this section may be manufactured such that when the expandable section 204 expands within the lumen 210 under a first positive pressure, this section does not expand under the first positive pressure. In some embodiments, the non-inflatable section 212 may be made of an elastomeric material that is harder than the expandable section 204, such that the non-inflatable section 212 resists radial tension, while the expandable section 204 resists radial tension. Alternatively or additionally, the non-inflatable section 212 may have a thicker section of conduit 202 than the expandable section 204 to resist expansion when the expandable section 204 expands. In some embodiments, additionally or alternatively, the non-inflatable section 212 may include reinforcing material along the length 250 of the conduit 202. This reinforcing material may be placed around the conduit 202 like a sleeve and / or placed within the wall of the conduit 202 (e.g., embedded within the material of the conduit 202). In some embodiments, and as... Figure 7A As shown, reinforcement 220 is positioned along the non-expandable section 212. Reinforcement 220 can be a braid made of materials such as metal wire (e.g., stainless steel, nitinol, etc.), para-aramid, glass fiber, carbon fiber, etc. Alternatively, reinforcement 220 can be a coil made of materials such as metal wire (e.g., stainless steel, nitinol, etc.), para-aramid, glass fiber, carbon fiber, etc. A second reinforcement 222 is also envisioned to be positioned along a length 250 of the conduit 202 distal to the expandable section 204 to ensure that the conduit 202 resists expansion both proximal and distal to the expandable section 204. The second reinforcement 222 can be similar to the first reinforcement 220, but it is also envisioned that the first and second reinforcements can comprise different materials.

[0044] exist Figures 7A to 7CIn some specific embodiments of the catheter shown, catheter 200 includes an inner liner 602 and an outer polymer sheath 604 made of highly oriented PTFE. The orientation of the polymer chains in the PTFE liner makes the axial stiffness (or elongation) of the PTFE liner significantly greater than that of the outer polymer sheath 604, eliminating the need for axial fibers to provide tensile strength to the catheter. The encapsulated PTFE liner is an example of such a liner material. Specifically, the preferred inner liner 602 has an elastic modulus greater than 1,000 MPa (N / mm²), and preferably greater than 1,500 MPa, and most preferably close to or greater than 2,000 MPa. Because the inner liner 602 can be made with very thin walls and is located inside the catheter 200, its negative impact on the lateral flexibility of the catheter 200 can be minimized. The outer catheter sheath 604 has a large diameter and wall thickness, and is therefore geometrically configured to have a large area quadratic moment. However, because the outer sheath 604 can be made of a polymer with a much lower elastic modulus than the inner liner 602, its contribution to the axial and lateral stiffness of the catheter is reduced. Specifically, the elastic modulus of the preferred outer sheath 604 is less than 10% of the elastic modulus of the inner liner 602, and preferably, it is close to or less than 1% of the elastic modulus of the inner liner 602. A significant advantage of this construction is that the resulting catheter is extremely flexible and also very tensile-resistant, so that if the distal end 208 becomes lodged in the vessel 10 after embolization, it can be safely pulled out without the risk of the catheter 200 breaking and remaining partially in the patient's body.

[0045] Now for reference Figures 8A to 8F The design therein provides a delivery conduit 300 having an umbrella-shaped expandable section 304 according to various aspects of this disclosure. For example, Figures 8A to 8F The delivery catheter 300 has a length 350 of catheter conduit 302, and an expandable section 304 is positioned along this length. As described above, catheter conduit 302 may include a central lumen 310 disposed therethrough. Figures 8A to 8F The expandable section 304 in the example includes a fixed proximal collar 324 and a membrane 322 having an open end 320. The expandable section 304 includes a collapse structure having a first diameter 352 (see [link to example]). Figure 8F ) and an expansion structure with a second diameter of 354 (see Figure 8D ,or Figure 8E (Radial cross-sectional view in the diagram). The second diameter 354 is sized to prevent backflow of the adhesive proximal to the expandable segment 304 within the vessel 10. As shown, a fixed proximal collar 324 is attached to the catheter conduit 302, and the open end 320 of the membrane 322 extends distally such that any backflow of the fluid embolic agent from the distal end 308 is trapped within the membrane 322.

[0046] Figure 8AAn expandable segment 304 with a bulbous shape is shown, wherein the opening end 320 of the membrane 322 has an opening diameter 356 smaller than a second diameter 354, which is closer to the center (longitudinal) of the expandable segment 304. Therefore, the expandable segment 304 can contact the vessel wall 102, and the opening diameter 356 can taper slightly inward to facilitate insertion. The radial force provided by the expandable segment 304 allows for insertion from the proximal end (from...) Figure 8A When pressure is applied (as shown on the left side of the image), membrane 322 may collapse. This pressure, for example, can originate from fluid injection through the intermediate conduit. The delivery conduit 300 may also include a transmissive strip 314 disposed near the distal end 308, and the transmissive strip 314 may resemble the one referenced above. Figures 7A to 7C The non-transmissive band 214 is discussed. Figure 8B Provided Figure 8A A side sectional view of the catheter in the middle, and Figure 8C yes Figure 8B The radial cross-sectional view of the conduit along line 8C-8C.

[0047] Refer again Figures 8D to 8F In this example, the expandable segment 304 includes a frame 326 extending from a fixed proximal collar 324. The frame 326 includes a sliding distal collar 328 distal to the fixed proximal collar 324. The sliding distal collar 328 is movable to allow the expandable segment 304 to collapse in a configuration (see...). Figure 8F The expandable section 304 has a collapse length of 376 and an expansion structure (see [reference]). Figure 8D The expandable segment 304 transitions between expansion lengths 374 and expansion lengths 374. The membrane 322 is attached to the frame 326 and expands and collapses together with the frame 326. The membrane 322 may comprise silicone, polyurethane, polypropylene, polyethersulfone, etc. The material used for the membrane 322 is flexible, allowing it to be opened when the expandable segment 304 opens from a collapsed configuration to an expanded configuration. In some examples, and as... Figures 8D to 8F As shown, frame 326 may include a plurality of axial rods 330 extending (e.g., along longitudinal axis 316) between a fixed proximal collar 324 and a sliding distal collar 328. Membrane 322 may be attached to the axial rods 330. To provide the open end 320 of membrane 322, membrane 322 does not need to extend distally to the sliding distal collar 328 completely. Alternatively, membrane 322 may extend distally from the fixed proximal collar 324 to a midpoint between the fixed proximal collar 324 and the sliding distal collar 328, for example, at a point such that… Figure 8D The midpoint shown.

[0048] Now for reference Figure 8G Frame 326 may have Figures 8D to 8F Alternative designs shown Figures 8D to 8F A rod 330 is shown that extends axially along the longitudinal axis 316 and terminates at the sliding distal collar 328. Figure 8G The example frame 326 shown provides a solution in which frame 326 does not include a sliding distal collar 328. In this example, two adjacent axial rods 330 are integrally formed distally via annular ends 334, thereby providing a non-invasive distal profile for the expandable segment 304. Frame 326 may be made of a material that can automatically return to its shape once unshuffled into its expanded configuration. This material may be in various forms, such as wire, strip, sheet, or tubular. In some examples, frame 326 may contain, but is not limited to, nitinol, stainless steel, MP35N, tungsten, etc., or any combination or alloy thereof. In some examples, the material may be made of a shape-memory material (such as nitinol), and the expanded configuration of the expandable segment 304 may be achieved by heat-shaping the material into an expanded configuration (e.g., Figure 8G It is made by means of (as shown in the figure), and then the expandable section 304 can expand when positioned at the treatment site.

[0049] Figures 9A to 9E This is a side view of a catheter 400 that utilizes a fluid column 454 to prevent backflow of the fluid embolizing agent 452 according to various aspects of this disclosure. The example catheter 400 shown in the figure utilizes a circulating pulse of a second fluid other than gel. The second fluid may include, for example, saline, or another fluid such as a dextran solution (e.g., a medical 5% dextran solution). By cyclically pulsating the second fluid, a pulsating effect can be used to prevent the fluid embolizing agent 452 from flowing proximally. The fluid column 454 can act as a barrier and then close, thereby allowing the catheter 400 to be removed while the shaped fluid embolizing agent 452 remains in place. The catheter 400 includes a catheter conduit 402 extending to a distal end 408, wherein the fluid embolizing agent 452 and the fluid column 454 can exit the catheter 400 near the distal end 408. Figures 9A to 9D The progress made in using fluid column 454 to prevent backflow is shown. Figure 9A This is a side view of catheter 400 prior to delivery of fluid embolization agent 452 or a second fluid (e.g., saline); Figure 9B This is a side view of catheter 400 discharging fluid embolic agent 452; Figure 9C This is a side view of the catheter 400 discharging a fluid column 454 to block the backflow of the fluid embolizing agent 452; and Figure 9D This is a side view of catheter 400, with the fluid embolizing agent 452 away from the distal end 408, because in this view, the fluid embolizing agent 452 has been injected at the treatment site and catheter 400 can be withdrawn.

[0050] The catheter 400 may include a pharmaceutical conduit 456 in fluid communication with the distal end 408 of the catheter conduit 402 to provide a fluid embolic agent 452; the catheter 400 may also include a fluid conduit 458 in fluid communication with the distal end 408 of the catheter conduit 402 to provide fluid for a fluid column 454. The catheter 400 may include a pharmaceutical pump 462 to drive the fluid embolic agent 452 through the pharmaceutical conduit 456; the catheter 400 may include a circulation pump 464 to drive a second fluid to the distal end 408 of the catheter conduit 402 via a circulating pulse. Referring now to the circulating pulse, the catheter 400 may alternate between driving the fluid embolic agent 452 and driving the fluid for the fluid column 454. The pharmaceutical pump 462 and the circulation pump 464 alternately inject the adhesive and fluid (e.g., saline or another fluid) to ensure that the adhesive continues to receive distal force from the fluid to avoid backflow. In some embodiments, fluid conduits 458 and pharmaceutical conduits 456 may converge at a conduit junction 460, which is in fluid communication with conduit 402 at its distal end and includes fluid communication with both fluid conduits 458 and pharmaceutical conduits 456 at its proximal end. In some embodiments, conduit 400 may simultaneously drive fluid embolizing agent 452 and fluid for fluid column 454, thereby generating a surging effect to accompany the delivery of fluid embolizing agent 452.

[0051] The medication pump 462 may be connected to a reservoir (e.g., vial or bag) that includes the fluid embolic agent 452. Alternatively or additionally, the medication pump 462 may be a positive displacement pump configured to continuously drive the fluid embolic agent 452 through the medication line 456 during a cyclic pulse. The circulation pump 464 may be in fluid communication with the fluid reservoir 466 (e.g., a sterile saline bag). The circulation pump 464 may also be a syringe that includes fluid 459 to form a fluid column 454. This syringe design also allows the circulation pump 464 to provide a degree of vacuum to the treatment area; for example, the syringe may be pressed inward to deliver fluid and pulled out to provide a slight vacuum to prevent excess fluid 459 (e.g., saline or another fluid) from accumulating proximally to the injected fluid embolic agent 452. It is also conceivable that the circulation pump 464 may have a vacuum connection 468 to an external vacuum source, which is available in most operating room environments.

[0052] Now for reference Figure 9EThe design shown provides an example of how the fluid column 454 does not need to be limited to the distal end 408 of the conduit 402. In some examples, a drug conduit 456 may be disposed within the fluid conduit 458, such that fluid 459 for the fluid column 454 flows within and around the drug conduit 456. The distal end of the fluid conduit 458 may include one or more orifices 470 positioned near the distal end of the fluid conduit 458 to allow fluid 459 to exit the conduit proximal to the end of the conduit 402. The orifices 470 may be positioned from 1 mm to 10 mm (e.g., 5 mm) from the end to allow the formation of a fluid column 454 along the end of the conduit 402, preventing or limiting the proximal backflow of the fluid embolic agent 452. The orifice 470 may include a hole in the conduit 202, which may be a circular hole or any other shape of hole, to allow fluid to flow out through the conduit 202.

[0053] The design aspects described herein can be achieved through any of the following numbered clauses: Clause 1: A delivery catheter (100) comprising: a catheter conduit (120) extending for a length (500), a proximal portion (220) of the catheter conduit (120) having a first diameter (800) and a distal portion (240) of the catheter conduit (120) having a second diameter (810); and a reflux occluder section (102) having a third diameter (820) greater than the first diameter (800) and the second diameter (810), the reflux occluder section (102) being disposed along the length (500) of the catheter conduit (120) between the proximal portion (220) and the distal portion (240).

[0054] Clause 2: The delivery catheter (100) as described in Clause 1, wherein the first diameter (800) of the catheter conduit (120) is greater than the second diameter (810) of the catheter conduit (120).

[0055] Clause 3: The delivery catheter (100) according to Clause 1 or 2, wherein the reflux occluder section (102) is a protrusion in the catheter conduit (120), and the reflux occluder section (102) is compressible to be inserted into the blood vessel (10) and is expandable to the third diameter (820).

[0056] Clause 4: The delivery conduit (100) as described in Clause 3, wherein the conduit (120) includes a braid (104) extending along the length (500) of the conduit (120).

[0057] Clause 5: The delivery catheter (100) according to Clause 4, wherein the distal end (112) of the braid (104) is positioned within the proximal portion (220) of the catheter conduit (120).

[0058] Clause 6: Delivery catheter (100) as described in Clause 4, wherein the distal end (112) of the braid (104) is located within the reflux occluder section (102).

[0059] Clause 7: The delivery catheter (100) according to Clause 4, wherein the distal end (112) of the braid (104) is positioned within the distal portion (240) of the catheter conduit (120).

[0060] Clause 8: The delivery catheter (100) according to Clause 4, wherein the distal end (112) of the braid (104) includes a braid attachment (106) which is a loop having a non-invasive distal end.

[0061] Clause 9: The delivery catheter (100) as described in Clause 8, wherein the braided attachment (106) comprises a non-transparent material.

[0062] Clause 10: Delivery conduit (100) as described in Clause 1 or 2, wherein the backflow occluder section (102) is one or more baffles (306 / 314) extending from the conduit (120).

[0063] Clause 11: The delivery catheter (100) according to Clause 10, wherein the one or more baffles (306 / 314) include a helical baffle (306) that is helical about the longitudinal axis (550) of the delivery catheter (100).

[0064] Clause 12: The delivery conduit (100) according to Clause 10 or 11, wherein the one or more baffles (306 / 314) include a first helical baffle (302) and a second helical baffle (304) radially offset from the first helical baffle (302).

[0065] Clause 13: The delivery conduit (100) according to Clause 10, wherein the one or more baffles (306 / 314) include an annular baffle (314) extending radially from the conduit (120).

[0066] Clause 14: The delivery conduit (100) according to Clause 10 or 13, wherein the one or more baffles (306 / 314) include a first annular baffle (308) having a first baffle diameter (830) and a second annular baffle (310) having a second baffle diameter (840), the first baffle diameter (830) being smaller than the second baffle diameter (840).

[0067] Clause 15: Delivery catheter (100) according to any one of the preceding clauses, wherein the catheter conduit (120) includes a braid (104) extending along the length (500) of the catheter conduit (120).

[0068] Clause 16: Delivery catheter (100) according to any one of the preceding clauses, wherein the third diameter (820) is smaller than the diameter of the target blood vessel (10).

[0069] Clause 17. The delivery catheter (100) according to any one of the preceding clauses, wherein the catheter conduit (120) includes an inner liner (602) and an outer sheath (604), wherein the inner liner (602) comprises highly oriented polytetrafluoroethylene (PTFE), and wherein the elastic modulus of the outer sheath (604) is less than 10% of the elastic modulus of the inner liner (602).

[0070] Clause 18: A delivery catheter (100) comprising: a catheter conduit (120) extending a length (500) and including a braid (104) extending along the length (500) of the catheter conduit (120); and a reflux occluder section (102) disposed along the length (500) of the catheter conduit (120) between a proximal portion (220) and a distal portion (240) of the catheter conduit (120), wherein a distal end (112) of the braid (104) is positioned within the reflux occluder section (102).

[0071] Clause 19: The delivery catheter (100) as described in Clause 18, wherein the catheter conduit (120) includes axial fibers (402).

[0072] Clause 20: The delivery catheter (100) according to Clause 18 or 19, wherein: the proximal portion (220) of the catheter conduit (120) has a first diameter (800), and the distal portion (240) of the catheter conduit (120) has a second diameter (810); and the reflux occluder section (102) has a third diameter (820) greater than the first diameter (800) and the second diameter (810).

[0073] Clause 21: A method comprising: advancing a distal end (110) of a delivery catheter (100) through a main vessel (10) to a location distal to a non-target site (14) and proximal to a target site (16); positioning a reflux occluder segment (102) proximal to the target site (16) such that the reflux occluder segment (102) extends radially from the catheter conduit (120) of the delivery catheter (100) and contacts the vessel wall (12) adjacent to the target site (16); delivering via the catheter conduit (120) The fluid embolizing agent is delivered; the proximal reflux of the fluid embolizing agent in the reflux occluder section (102) is restricted via the reflux occluder section (102); and the delivery catheter (100) is removed from the main vessel (10), wherein the reflux occluder section (102) has an occluder diameter (820) that is larger than the proximal diameter (800) of the proximal portion (220) of the catheter conduit (120) and also larger than the distal diameter (810) of the distal portion (240) of the catheter conduit (120).

[0074] Clause 22: A delivery catheter (200) comprising: a length (250) of a catheter conduit (202); a non-inflatable section (212) positioned along the length (250); an inflatable section (204) disposed distal to the non-inflatable section (212) along the length (250); and a limiter (206) disposed at the conduit (202) distal to the inflatable section (204). Within the lumen (210), the expandable segment (204) includes a collapse structure having a first diameter (252) and an expansion structure having a second diameter (254), the second diameter (254) being sized to restrict the backflow of fluid embolic agent within the blood vessel (10) proximal to the expandable segment (204), and wherein the catheter conduit (202), the non-expandable segment (212), and the expandable segment (204) share a single lumen (210).

[0075] Clause 23: The delivery conduit (200) according to Clause 22, wherein the restrictor (206) is a material ring within the lumen (210) that reduces the flow of fluid embolic agent through the lumen (210), and wherein the reduction of flow generates positive pressure at the expandable section (204) to cause the expandable section (204) to expand from the collapsed structure to the expanded structure.

[0076] Clause 24: The delivery conduit (200) according to Clause 22, wherein the non-inflatable section (212) includes reinforcing material disposed within the non-inflatable section (212) along the conduit conduit (202), the reinforcing material providing radial support to the conduit conduit (202) within the non-inflatable section (212) to prevent or reduce expansion of the non-inflatable section (212).

[0077] Clause 25: The delivery conduit (200) as described in Clause 24, wherein the reinforcing material (220) is a first braid or a first coil.

[0078] Clause 26: The delivery conduit (200) as described in Clause 25, wherein the reinforcing material (220) is embedded within the conduit channel (202).

[0079] Clause 27: The delivery catheter (200) as described in Clause 22 further includes a nontransparent strip (214) positioned along the length (250) near the limiter (206).

[0080] Clause 28: The delivery catheter (200) according to Clause 27, wherein the non-transparent strip (214) is positioned along the length (250) between the expandable section (204) and the limiter (206).

[0081] Clause 29: The delivery conduit (200) as described in Clause 22, wherein the conduit (202) includes a second reinforcing material (222) positioned around the limiter (206).

[0082] Clause 30: The delivery catheter (200) according to Clause 22, wherein the catheter conduit (202) includes an inner liner (602) and an outer sheath (604), wherein the inner liner (602) comprises highly oriented polytetrafluoroethylene (PTFE), and wherein the elastic modulus of the outer sheath (604) is less than 10% of the elastic modulus of the inner liner (602).

[0083] Clause 31: A delivery catheter (300) comprising: a length (350) of a catheter conduit (302); and an expandable segment (304) positioned along the length (350), the expandable segment (304) comprising: a fixed proximal collar (324); and a membrane (322) having an open end (320), wherein the expandable segment (304) includes a collapse configuration having a first diameter (352) and an expansion configuration having a second diameter (354), the second diameter (354) being sized to restrict backflow of a fluid embolic agent within the blood vessel (10) proximal to the expandable segment (304).

[0084] Clause 32: The delivery catheter (300) according to Clause 31, wherein the expandable segment (304) includes a frame (326) extending from the fixed proximal collar (324), the frame (326) including a sliding distal collar (328) movable to allow the expandable segment (304) to transition between the collapsed configuration and the expanded configuration.

[0085] Clause 33: The delivery catheter (300) according to Clause 32, wherein the frame (326) includes a plurality of axial rods (330) extending between the fixed proximal collar (324) and the sliding distal collar (328), and wherein the membrane (322) is attached to the axial rods (330).

[0086] Clause 34: The delivery catheter (300) according to Clause 33, wherein the open end (320) is positioned between the fixed proximal collar (324) and the sliding distal collar (328).

[0087] Clause 35: The delivery conduit (300) according to Clause 33, wherein two adjacent axial rods (330) are integrated distally via annular ends (334).

[0088] Clause 36: The delivery catheter (300) according to Clause 31, wherein the open end (320) has an opening diameter (356) smaller than that of the second diameter (354).

[0089] Clause 37: A delivery catheter (400) comprising: a catheter conduit (402) having a distal end (408); a drug conduit (456) in fluid communication with the distal end (408) of the catheter conduit (402); a drug pump (462) for driving a fluid embolic agent (452) through the drug conduit (456); and a fluid conduit (458) in flow with the distal end (408) of the catheter conduit (402). Body connection; circulation pump (464) for driving a second fluid to the distal end (408) of the conduit (402) in a circulating pulse, wherein the circulating pulse generates a fluid column (454) positioned between the distal end (408) and the fluid embolizer (452) near the distal end (408) to limit the backflow of the fluid embolizer (452) to the proximal side of the distal end (408), and wherein the second fluid is a different material from the fluid embolizer (452).

[0090] Clause 38: The delivery catheter (400) according to Clause 37 further includes a conduit junction (460) communicating at a first end with the conduit conduit (402) and at a second end with (i) the drug conduit (456) and (ii) the fluid conduit (458).

[0091] Clause 39: According to the delivery conduit (400) of Clause 37, the circulation pump (464) is configured to circulate between driving the second fluid and providing suction through the distal end (408) of the conduit (402).

[0092] Clause 40: The delivery catheter (400) as described in Clause 37, wherein the circulation pump (464) is a syringe that includes the second fluid.

[0093] Clause 41: The delivery conduit (400) according to Clause 37, wherein the agent pump (462) is a positive displacement pump configured to drive the fluid embolic agent (452) continuously through the agent conduit (456) during the cyclic pulse.

[0094] This disclosure is not necessarily limited to the described examples, the construction and details of which may vary. The terms “distal” and “proximal” are used throughout the foregoing description and refer to position and orientation relative to the treating physician. Similarly, “distal” or “towards distal” refers to a position away from the physician or in a direction away from the physician. Likewise, “proximal” or “towards proximal” refers to a position closer to the physician or in a direction toward the physician. Furthermore, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the / described” include plural references.

[0095] As used herein, the term “about” or “approximately” for any numerical value or range indicates appropriate dimensional tolerances that allow a collection of parts or components to achieve the intended purpose as described herein. More specifically, “about” or “approximately” may refer to a range of ±20% of the enumerated value; for example, “about 90%” may refer to a range of values ​​from 70.1% to 109.9%.

[0096] In describing the example embodiments, terminology is used for clarity. Therefore, not all possible combinations are listed, and such variations are generally obvious to those skilled in the art and are intended to fall within the scope of the following claims. Without departing from the scope and spirit of this disclosure, each term is intended to be contemplated for the broadest meaning understood by those skilled in the art, and includes all technical equivalents that operate in a similar manner to achieve a similar purpose. It should also be understood that reference to one or more steps of the method does not exclude the presence of additional method steps or intermediate method steps between those expressly identified steps. Similarly, without departing from the scope of the disclosed technology, some steps of the method may be performed in an order different from that described herein.

Claims

1. A delivery catheter, the delivery catheter comprising: A catheter extending a length, the proximal portion of the catheter having a first diameter and the distal portion of the catheter having a second diameter; and A reflux occluder section having a third diameter greater than the first and second diameters, the reflux occluder section being disposed along the length of the conduit between the proximal and distal portions.

2. The delivery catheter of claim 1, wherein the first diameter of the catheter conduit is larger than the second diameter of the catheter conduit.

3. The delivery catheter of claim 1, wherein the reflux occluder section is a protrusion in the catheter conduit, and the reflux occluder section is compressible for insertion into a blood vessel and expandable to the third diameter.

4. The delivery catheter of claim 3, wherein the catheter conduit includes a braid extending along the length of the catheter conduit; wherein the distal end of the braid is positioned within: (i) the proximal portion of the catheter conduit; (ii) the reflux occluder section; or (iii) the distal portion of the catheter conduit.

5. The delivery catheter of claim 4, wherein the distal end of the braid includes a braid attachment, the braid attachment being a loop having a non-invasive distal end.

6. The delivery catheter of claim 1, wherein the reflux occluder section comprises one or more baffles extending from the catheter conduit; wherein the one or more baffles comprise: (i) a spiral baffle that spirals about the longitudinal axis of the delivery conduit; (ii) a first spiral baffle and a second spiral baffle that is radially offset from the first spiral baffle; (iii) an annular baffle that extends radially from the conduit; or (iv) a first annular baffle having a first baffle diameter and a second annular baffle having a second baffle diameter, wherein the first baffle diameter is smaller than the second baffle diameter.

7. The delivery catheter of claim 1, wherein the catheter tubing comprises an inner liner and an outer sheath, wherein the inner liner comprises highly oriented polytetrafluoroethylene (PTFE), and wherein the elastic modulus of the outer sheath is less than 10% of the elastic modulus of the inner liner.

8. The delivery catheter of claim 7, wherein the catheter conduit comprises axial fibers.

9. A method of using the delivery catheter according to claim 1, wherein the method comprises the following steps: The distal end of the delivery catheter is advanced through the main blood vessel to a position distal to the non-target site and proximal to the target site; Position the reflux occluder segment proximal to the target site such that the reflux occluder segment extends radially from the catheter conduit of the delivery catheter and contacts the vessel wall near the target site; Fluid embolic agent is delivered through the catheter; The fluid embolizing agent is restricted from refluxing proximal to the refluxing blocker section via the refluxing blocker section; and The delivery catheter is withdrawn from the main blood vessel. The reflux occluder section includes an occluder diameter that is larger than the proximal diameter of the proximal portion of the conduit and also larger than the distal diameter of the distal portion of the conduit.

10. A delivery catheter, the delivery catheter comprising: A conduit or tubing of one length; and An expandable segment, positioned along the length, comprising: Fixed proximal collar; and A membrane with an open end, The expandable segment has a collapse structure and an expansion structure, the collapse structure having a first diameter and the expansion structure having a second diameter, the second diameter being sized to restrict the backflow of the fluid embolic agent within the blood vessel proximal to the expandable segment.

11. The delivery catheter of claim 10, further comprising: A non-expandable segment, wherein the non-expandable segment is positioned along the length; and A limiter disposed within the lumen of the conduit distal to the expandable section; The conduit, the non-expandable section, and the expandable section share a single lumen.

12. The delivery catheter of claim 11, wherein the restrictor is a material ring within the lumen that reduces the flow of fluid embolic agent through the lumen, and wherein the reduction in flow generates positive pressure at the expandable section to cause the expandable section to expand from the collapsed configuration to the expanded configuration.

13. The delivery catheter of claim 11, further comprising a non-transparent strip positioned along the length near the limiter.

14. The delivery catheter of claim 10, wherein the expandable segment includes a frame extending from the fixed proximal collar, the frame including a sliding distal collar movable to allow the expandable segment to transition between the collapsed configuration and the expanded configuration.

15. The delivery catheter of claim 14, wherein the frame includes a plurality of axial rods extending between the fixed proximal collar and the sliding distal collar, and wherein the membrane is attached to the axial rods.

16. The delivery catheter of claim 15, wherein the open end is positioned midway between the fixed proximal collar and the sliding distal collar.

17. The delivery catheter of claim 15, wherein two adjacent axial rods are integrally formed distally via annular ends.

18. The delivery catheter of claim 10, wherein the opening end has an opening diameter smaller than the second diameter.

19. A delivery catheter, the delivery catheter comprising: A catheter conduit having a distal end; A pharmaceutical conduit, which is in fluid communication with the distal end of the conduit; A pharmaceutical pump that drives a fluid embolizing agent through the pharmaceutical conduit; A fluid conduit, which is in fluid communication with the distal end of the conduit; and A circulation pump that drives a second fluid to the distal end of the conduit with circulating pulses. The cyclic pulse generates a fluid column positioned between the distal end and the fluid embolizing agent near the distal end to limit backflow of the fluid embolizing agent proximal to the distal end. The second fluid is a material different from the fluid embolizing agent.

20. The delivery catheter of claim 19, wherein the circulation pump is a syringe comprising the second fluid; and the drug pump is a positive displacement pump configured to continuously deliver the fluid embolic agent during the circulation pulse.

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