Balloon catheter with improved characteristics

Abstract

A balloon catheter is disclosed with the feature of reducing balloon adhesiveness to ensure a more uniform inflation profile. In some embodiments, a balloon guide catheter is disclosed that includes a conduit or passage for an additional catheter or device.

Description

Technology Field

[0001] This document relates to a balloon catheter with improved characteristics. Background Technology

[0002] Balloon catheters can be used in various vascular procedures, including flow cessation, flow reversal, and occlusion, as scaffolds for subsequently delivered medical devices, and as part of aspiration or thrombus recovery procedures to block blood flow to prevent blood clots or thrombi from leaving the target site during recovery. Some balloon catheters are designed for neurovascular applications, and these catheters have a small size to track smaller vessels in the area. The associated balloon must generally be very soft or flexible to prevent vascular damage and to follow the shape of the vessel.

[0003] Balloon catheters, particularly double-lumen balloon catheters, can face the problem of the uninflated balloon inadvertently adhering or sticking to parts of the catheter (e.g., the lumen or passage of the internal guidewire) during inflation. This effect is pronounced when the balloon is very soft or flexible, which is a general characteristic of balloons used for neurovascular applications due to the small size of the vessels, as well as to enhance flexibility to reach smaller and more distal vessels.

[0004] Such adhesion or careless adhesion can lead to incomplete balloon inflation, causing the inflated balloon to have an asymmetrical or incomplete expansion shape within the patient's blood vessel being treated, potentially limiting the effectiveness of the therapeutic procedure. For example, in a flow stop procedure, if the balloon is not fully filled (e.g., when blood flow is stopped proximal to aid in performing the procedure), blood still reaches the treatment site, making the procedure more difficult. In one example, a balloon may be used as part of an aspiration or mechanical thrombus recovery procedure, where it is used for proximal flow stop to help prevent blood clots or thrombi from being removed downstream during the procedure. However, adhesion of the balloon causes it to adopt an incomplete profile, preventing the flow stop from functioning as intended, and allowing blood clots or thrombi to dislodge or escape downstream.

[0005] Doctors may attempt to compensate for these problems by overfilling the balloon with additional inflation medium to alleviate asymmetry or ensure it adopts a fully inflated shape; however, this results in excessive pressure, which can cause vascular trauma to the patient or lead to the rupture of the balloon.

[0006] One possible solution to this problem is to use a more rigid balloon material to reduce balloon compliance / softness. However, a major drawback is that more rigid balloons are less flexible and consequently cannot adaptively accommodate complex vascular geometries, which can cause vascular trauma. Such balloons can also cause complications in specific small blood vessels (e.g., those of the neurovascular system).

[0007] Rigir materials also affect the traceability of balloon catheters and make it difficult to track the catheter around curved bends. In one scenario, a balloon catheter used in neurovascular procedures must typically be tracked through a carotid siphon, which involves U- or S-shaped bends in the carotid artery. During endovenous procedures such as vascular occlusion, aspiration, reflux, or thrombus recovery, it may be desirable to use a balloon catheter to access the cerebral blood vessels beyond the carotid siphon. However, designing a balloon catheter to be flexible enough to navigate curved bends (e.g., a carotid siphon) can be challenging, and potential balloon adhesion issues may arise, particularly when a soft, flexible balloon is required.

[0008] Therefore, there is a need for a balloon catheter capable of satisfying at least these minimum requirements: flexibility to track curved bends, and the ability to use a soft, flexible balloon that does not stick to the catheter.

[0009] Many medical procedures utilize guide catheters as conduits for smaller catheters (e.g., microcatheters) used to access target areas or deliver therapeutic devices used in the procedure. Guide catheters are larger and more rigid than the smaller catheters through which they are delivered, and they are intended to act as supporting structures for the smaller catheters / devices delivered through them. An ideal guide catheter can be flexible enough to navigate curved anatomical structures (e.g., the aforementioned carotid siphon) and strong enough to withstand anatomical pulsating pressures to provide sufficient structural strength to support the placement of the device through the smaller catheter or device.

[0010] For example, a balloon guide catheter containing a balloon that can provide a proximal stop to enhance therapeutic procedures (e.g., thrombus recovery via aspiration or mechanical thrombectomy) and has a passage large enough to accommodate a catheter or additional medical devices can offer significant advantages. However, such devices can be difficult to design. For instance, the inclusion of a balloon significantly increases the complexity of the guide catheter, as it requires a balloon that can greatly increase the rigidity of the guide catheter due to a separate expansion lumen and additional components. This increased rigidity can impair the traceability of the guide catheter through curved anatomical structures, such as carotid siphons. Additionally, while there are advantages to using flexible / compliant balloons (e.g., in neurovascular spaces), such as non-traumatic damage to the vessel wall during expansion, these balloons can cause stickiness or adhesion issues as described above.

[0011] Furthermore, these catheters require a balance of flexibility and rigidity / strength. If a balloon guide catheter is too rigid, it cannot navigate curved anatomical structures (e.g., carotid siphon) and may end up being placed too far from the desired destination to provide any benefit (e.g., flow stoppage for optimal thrombus recovery). This distance may also require the physician to track the thrombus from a greater distance into the guide catheter, which can introduce complexity by increasing the risk of the thrombus fragmenting or falling out during the recovery procedure. On the other hand, if the balloon guide catheter is too flexible, it may not be rigid enough to support a smaller catheter or treatment device delivered through its lumen, potentially preventing the physician from completing the procedure.

[0012] Therefore, there is a need for a balloon guide catheter capable of satisfying at least these minimum requirements: flexibility to track curved bends, the ability to use a soft, flexible balloon that does not adhere to the catheter, and sufficient structural strength for the catheter or device delivered through the passage of the balloon guide catheter.

[0013] In one embodiment, a balloon guide catheter is disclosed. The balloon guide catheter utilizes an inner assembly serving as a passage for a subsequently delivered therapeutic or procedure device / material (e.g., guidewire, catheter, thrombectomy device, aspiration / suction, embolus coil and / or liquid embolus) and an outer assembly delivering an inflatable fluid to the balloon. In one embodiment, the inner assembly of the balloon guide catheter includes a passage for a smaller catheter used as a conduit for a subsequently delivered therapeutic or procedure device / material (e.g., thrombectomy device, aspiration / suction, embolus coil, liquid embolus, embolus mesh, embolus or drug-containing beads, a smaller procedure balloon catheter, etc.).

[0014] In one embodiment, a balloon guide catheter having a flexible balloon and a mechanism for preventing balloon adhesion is disclosed. In one embodiment, the mechanism for preventing balloon adhesion—as a method to prevent this problem—can be used not only with balloon guide catheters but also with balloon catheters of various sizes and functions.

[0015] In one embodiment, the mechanism is one or more grooves located along the outer portion of the inner assembly of the balloon catheter. In one embodiment, one or more grooves are arranged longitudinally around the perimeter of the inner assembly of the balloon catheter. In one embodiment, one or more grooves are arranged surrounding the perimeter of the inner assembly of the balloon catheter. In one embodiment, one or more grooves are arranged spirally around the perimeter of the inner assembly of the balloon catheter.

[0016] In one embodiment, the mechanism is one or more elevations located along the outer portion of the inner assembly of the balloon catheter. In one embodiment, one or more elevations are arranged longitudinally and / or radially. In one embodiment, one or more elevations are spot elevations or spot projections located at multiple positions along the outer portion of the inner assembly of the balloon catheter.

[0017] In one embodiment, the mechanism is one or more depressions located along the outer portion of the inner assembly of the balloon catheter. In one embodiment, one or more depressions are arranged longitudinally and / or radially. In one embodiment, one or more depressions are spot depressions located at multiple positions along the outer portion of the inner assembly of the balloon catheter.

[0018] In one embodiment, the mechanism is one or more radially oriented elevations / projections or indentations / depressions / grooves located along the internal assembly of the balloon catheter. In one embodiment, radially oriented elevations or grooves are created by coiled elements. In one embodiment, radially oriented elevations or grooves are created by mesh elements.

[0019] In one embodiment, the balloon guide catheter utilizes a membrane on the distal portion of the balloon catheter, wherein the membrane is substantially non-sticky to prevent balloon adhesion. In one embodiment, the membrane includes a gapped or incised area so as to expose a portion of the surface of the catheter underneath, and a mechanism to prevent balloon adhesion (such as those described above) is used along the exposed surface of the catheter to help prevent balloon adhesion.

[0020] In one embodiment, the balloon guide catheter utilizes a membrane on the distal portion of the balloon catheter and a purge or escape passage located below or radially adjacent to the membrane within the internal assembly of the balloon guide catheter, the purge or escape passage providing escape of gas from the balloon. In one embodiment, the membrane may include pores of a size that allow the passage of gas but block the passage of liquid (e.g., an inflating medium such as a contrast agent or saline solution), thereby keeping the balloon in an inflated state.

[0021] In one embodiment, a balloon guide catheter for performing a procedure around the carotid artery is disclosed. In one embodiment, a balloon guide catheter for performing a procedure around the internal carotid artery is disclosed. In one embodiment, a balloon guide catheter of size and configuration for navigating through a carotid siphon to perform a procedure around the cavernous body or clinoid segment of the internal carotid artery of the neurovascular system is disclosed. In one embodiment, the balloon guide catheter has an outer diameter of about 0.09 inches to 0.12 inches and an inner diameter / passage size of about 0.08 inches to 0.09 inches to accommodate a catheter smaller than the inner diameter of the internal assembly.

[0022] In one embodiment, a manufacturing method for preventing balloon adhesion is disclosed. In one embodiment, the method comprises the action of placing one or more longitudinal shouldering paths along the outer surface of a balloon catheter tubular element (e.g., an inner assembly of a balloon catheter). In one embodiment, the method comprises the action of placing one or more coils or meshes around the outer surface of a balloon catheter tubular element (e.g., an inner assembly of a balloon catheter), and in one embodiment, one or more coils or meshes are removed to leave an imprinted surface. In one embodiment, the method comprises the action of creating one or more ridged interfaces along the outer surface of a balloon catheter tubular element (e.g., an inner assembly of a balloon catheter). In one embodiment, the method comprises the action of creating one or more depressed, recessed, or indented interfaces along the outer surface of a balloon catheter tubular element (e.g., an inner assembly of a balloon catheter).

[0023] In one embodiment, a method for reducing adhesion to the balloon in a balloon catheter is disclosed. In one embodiment, the method includes the action of creating one or more longitudinal paths along the outer surface of a balloon catheter tubular element (e.g., an inner assembly of the balloon catheter) using a soldering iron. In one embodiment, the method includes the action of placing one or more coils wound around the outer surface of a balloon catheter element (e.g., an inner assembly of the balloon catheter) — in one embodiment, one or more coils are removed to leave an imprinted surface. In one embodiment, the method includes the action of placing one or more meshes around the outer surface of a balloon catheter element (e.g., an inner assembly of the balloon catheter) — in one embodiment, one or more meshes are removed to leave an imprinted surface. In one embodiment, the method includes the action of creating one or more ridged boundaries along the outer surface of a balloon catheter tubular element (e.g., an inner assembly of the balloon catheter). In one embodiment, the method comprises the action of creating one or more depressed, recessed, or indented interfaces along the outer surface of a balloon catheter tubular element (e.g., an inner assembly of a balloon catheter). In one embodiment, the method comprises the action of placing a membrane element around the outer surface of a portion of the balloon catheter tubular element (e.g., an inner assembly of a balloon catheter), wherein the membrane element is substantially non-adhesive. In one embodiment, a tubular band element is subsequently placed on the distal portion of the membrane element. In one embodiment, one or more raised interfaces are placed along the exposed surface of the balloon catheter tubular element (e.g., an inner assembly of a balloon catheter) to create an interface that prevents adhesion or bonding.In one embodiment, one or more depressed, recessed, or indented interfaces are positioned along the exposed portion of the balloon catheter tubular element corresponding to the gap of the upper membrane.

[0024] In one embodiment, a method for performing a vascular procedure is disclosed. In one embodiment, the method comprises the action of providing a balloon catheter (e.g., a balloon guide catheter) having a substantially non-sticky membrane element along a distal portion of a balloon catheter, the action of delivering the balloon catheter to a target treatment site, and the action of delivering an expansion fluid to the balloon to inflate the balloon, wherein the substantially non-sticky membrane element prevents the balloon from sticking and promotes proper inflation.

[0025] In one embodiment, a method for performing a vascular procedure is disclosed. In one embodiment, the method comprises providing a balloon catheter (e.g., a balloon guide catheter) having one or more raised interfaces along a distal portion of the balloon catheter, delivering the balloon catheter to a target treatment site, and delivering an expansion fluid to the balloon to inflate the balloon, wherein the raised interfaces prevent the balloon from adhering and promote proper inflation.

[0026] In one embodiment, a method for performing a vascular procedure is disclosed. In one embodiment, the method comprises the action of providing a balloon guide catheter and the action of tracking the balloon guide catheter through at least a portion of a carotid artery siphon, the action of inflating the balloon (e.g., to stop blood flow), and the action of positioning the catheter at a target treatment site to perform the procedure through the balloon guide catheter. In one embodiment, the procedure is aspiration and utilizes aspiration or vacuum through a catheter delivered through the balloon guide catheter. In one embodiment, the procedure is thrombectomy and utilizes a mechanical thrombus recovery device delivered through a catheter delivered through the balloon guide catheter. In one embodiment, the procedure is liquid embolus delivery and utilizes a liquid embolus delivered through a catheter delivered through the balloon catheter. In one embodiment, the procedure is embolus delivery and utilizes one or more embolus devices (e.g., embolus coils) delivered through a catheter delivered through the balloon catheter.

[0027] In one embodiment, a method for performing a vascular procedure is disclosed. In one embodiment, the method includes the action of providing a balloon guide catheter and the action of tracking the balloon guide catheter through at least a portion of a carotid artery siphon, the action of inflating the balloon (e.g., for stopping blood flow) and the action of using the lumen inside the balloon guide catheter to aspirate or place an instrument or material (e.g., a mechanical thrombus recovery device, a liquid embolus, or an embolization device) to a treatment site located near the balloon guide catheter.

[0028] In one embodiment, a method for performing a vascular procedure is disclosed. In one embodiment, the method comprises the action of providing a balloon guide catheter and the action of tracking the balloon guide catheter through at least a portion of a cavernous segment of the internal carotid artery, the action of inflating the balloon (e.g., to stop blood flow), and the action of using the lumen inside the balloon guide catheter to aspirate or place an instrument or material (e.g., a mechanical thrombus recovery device, a liquid embolus, or an embolization device) to a treatment site located near the balloon guide catheter.

[0029] In one embodiment, a method for performing a vascular procedure is disclosed. In one embodiment, the method comprises the action of providing a balloon guide catheter and the action of tracking the balloon guide catheter through at least a portion of the internal carotid artery, the step of inflating the balloon (e.g., to stop blood flow), and the action of using the lumen inside the balloon guide catheter to aspirate or place an instrument or material (e.g., a mechanical thrombus recovery device, a liquid embolus, or an embolization device) to a treatment site located near the balloon guide catheter. In one embodiment, the balloon guide catheter is tracked through at least one of the cervical (C1) segment, petrous (C2) segment, lacerum (C3) segment, cavernous (C4) segment, or clinoid (C5) segment of the internal carotid artery. Brief explanation of the drawing

[0030] These and other aspects, features, and advantages of the embodiments of the present invention may become apparent and clear from the following description of the embodiments of the present invention and the reference provided in the accompanying drawings, which are: Figure 1 shows a balloon attached to a part of a balloon catheter. Figure 2 shows a balloon with an incomplete profile formed by a balloon attached to a part of a balloon catheter. FIG. 3 illustrates a balloon catheter (e.g., a balloon guide catheter) according to one embodiment. FIG. 4 is a cross-sectional view of the balloon catheter of FIG. 3 according to one embodiment. FIG. 5 illustrates the distal region of the balloon catheter of FIG. 3 according to one embodiment. FIGS. 6a-6b illustrates a distal region of a balloon catheter comprising a non-sticky mechanism according to one embodiment. FIG. 6c is a cross-sectional view of a balloon catheter using a projecting surface according to one embodiment. FIG. 6d is a cross-sectional view of a balloon catheter using an indented surface according to one embodiment. FIG. 6e is a cross-sectional view of a balloon catheter using a projecting surface and an indented surface according to one embodiment. FIG. 6f is a cross-sectional view of a balloon catheter using a projecting surface and an indented surface according to one embodiment. FIG. 6g is a cross-sectional view of a balloon catheter using a plurality of projecting surfaces according to one embodiment. FIG. 6h is a cross-sectional view of a balloon catheter using a plurality of indented surfaces according to one embodiment. FIG. 6i is a cross-sectional view of a balloon catheter using a plurality of projecting surfaces and a plurality of indented surfaces according to one embodiment. FIG. 6k is a cross-sectional view of a balloon catheter using a plurality of spot projecting surfaces and a plurality of spot indented surfaces according to one embodiment. FIG. 61 is a cross-sectional view of a balloon catheter using a coil element used to create a helical grooved indentation according to one embodiment. FIG. 7 illustrates a distal region of a balloon catheter including a membrane and a purge passage according to one embodiment. FIG. 8 illustrates a balloon guide catheter used as a conduit for a smaller procedure catheter, according to one embodiment. Specific details for implementing the invention

[0031] This application claims priority to US No. 62 / 934,423, provisional application titled 'Non-stick Balloon Catheter', filed on November 12, 2019, and the entire contents of said application are incorporated herein by reference.

[0032] Specific embodiments are described below with reference to the attached drawings. However, the present invention may be implemented in a number of different forms and should not be interpreted as being limited to the embodiments described herein; rather, these embodiments are provided to ensure that the disclosure is thorough and complete and to sufficiently convey the scope of the invention to those skilled in the art. The terms used in the detailed description of the embodiments illustrated in the attached drawings are not intended to limit the embodiments. In the drawings, similar numbers refer to similar elements.

[0033] Here, proximal and distal directions may be referred to. Proximal refers to the direction toward the outside of the body, toward the physician performing the procedure, and away from the treatment site. Distal refers to the direction closer to the vascular system and closer to the target treatment site. In this way, medical devices being pushed in the distal direction (e.g., balloon catheters) are delivered closer to the treatment site, while devices being pulled in the proximal direction retract or move away from the treatment site.

[0034] As described above in the background technology section, balloon catheters may have a problem where the balloon adheres to a portion of the catheter. This adhesion occurs for various reasons. For example, if the balloon is soft and flexible, which is a common characteristic of neurovascular balloons, or in the case of balloons used in smaller or more sensitive vascular regions, this softness and compliance can cause such adhesion or stickiness to a portion of the balloon catheter (e.g., an internal portion located diametrically within the balloon).

[0035] Adhesion is primarily a problem in its undiffusing state, where a portion of the balloon can adhere to a part of the catheter. During inflation, the balloon region continues to adhere to the catheter surface, causing the balloon to become incompletely inflated or adopt an incompletely inflated shape.

[0036] FIG. 1 illustrates one such severe example where the balloon (102) adheres to a portion of the inner element / guidewire port (106) of the balloon catheter, causing a gap (108) that exposes a portion of the inner element (106), and thus the balloon does not fully inflate. The specific type of balloon catheter illustrated may be known as a double-lumen balloon catheter and utilizes one outer element that functions as an inflating lumen used to inflate the balloon and one inner element that functions as a guidewire port. One advantage of the double-lumen system is that the guidewire can be used to advance the balloon catheter to the treatment site using the inner element (106), where the balloon catheter is tracked on the guidewire. Procedures without such a guidewire port require the action of traversing the guidewire to the treatment site, the action of tracking the upper cover or guide catheter on the guidewire, the action of fully pulling out the guidewire, and then pushing the balloon catheter into the treatment site through the cover or guide catheter—this is a more laborious and time-consuming process.

[0037] In other examples, the balloon may adhere to other parts of the balloon catheter, such as the expansion lumen used to inflate the balloon. Such adhesion may occur in the aforementioned double-lumen device (including a guidewire port) or single-lumen balloon catheter (using only the external element / inflation lumen). FIG. 2 illustrates an example in which the adhesion of the balloon (102) causes the balloon to adopt an incomplete or asymmetrical shape (110).

[0038] The adhesiveness or adhesion of the balloon to parts of the balloon catheter can cause various complications, as described above in the background technology section. For example, this issue may prevent the balloon from adopting a complete profile (e.g., a complete circular, elliptical, or oval profile), which may reduce the effectiveness of the balloon during endovascular procedures.

[0039] Balloon catheters can be used in various procedures. For example, they can be used to create a proximal barrier to create flow stoppage or to increase suction force in aspiration procedures, to create a proximal barrier in liquid embolization procedures (e.g., to prevent the embolus from dissipating outside the treatment area), and as a scaffold or backstop in embolization procedures (e.g., vascular occlusion coils). If the balloon does not adopt a fully inflated shape, the effectiveness of these procedures may be reduced because the balloon is not completely sealed against the blood vessel. For example, in thrombectomy or aspiration procedures (where thrombectomy uses a mechanical thrombus recovery device and aspiration uses suction or vacuum to remove the thrombus), if the balloon does not adopt a completely / fully inflated shape to occlude the blood vessel, the thrombus may escape or the suction effect of the aspiration procedure may be reduced. In vascular occlusion procedures where a balloon acts as a scaffold, if the balloon fails to fully inflate, the vascular occlusion coil or device may dislodge from the treatment site (e.g., part of an aneurysm or occluded vessel), thereby reducing the effectiveness of the procedure or creating a risk of thrombosis if the device migrates to another location. In liquid embolization delivery procedures, if the balloon fails to fully inflate due to adhesiveness, the liquid embolus may reflux from the treatment site, potentially causing a risk of thrombosis or stroke in a proximal location, or blood may push the embolus distally, thereby treating the risk of thrombosis or stroke located distally. Liquid embolizers are generally used, for example, to occlude vascular occlusions or arteriovenous malformations (AVMs).

[0040] Balloon catheters and double-lumen balloon catheters including such balloon catheters for neurovascular treatment are disclosed in U.S. Patents No. 9,884,172 and No. 10,786,659, all of which are incorporated herein by reference in their entirety.

[0041] Doctors can address balloon adhesion problems by attempting to overinflate the balloon to force a fully inflated shape by inserting additional inflation medium. However, such over-inflation can cause the balloon to rupture or rapidly increase pressure on the blood vessel wall, leading to rupture over time or causing trauma to the blood vessel.

[0042] The embodiments presented in this document solve this problem by solving the balloon adhesion or bonding problem.

[0043] FIG. 3 illustrates a double lumen balloon catheter (200) according to one embodiment, which comprises an inflatable balloon (202), an outer assembly (204) having a passage (204a) that acts as a conduit for an inflating fluid to inflate the balloon, and an inner assembly (206) having its own passage within it. In one example, a liquid inflating medium, such as a contrast agent or saline solution, is used to inflate the balloon (202), wherein the inflating medium is delivered through the passage (204a) of the outer assembly (204).

[0044] Each of the inner (206) and outer (204) assemblies is tubular (e.g., each tubular assembly) and is arranged concentrically such that the inner assembly (206) is positioned concentrically within the outer assembly (204). Each of the inner (206) and outer (204) assemblies may be considered as tubular assemblies (e.g., inner tubular assembly (206) and outer tubular assembly (204)). Each of the inner (206) and outer (204) assemblies includes a passage, a channel, or an elongated lumen (206a, 204a) extending along its entire length. The outer assembly (204) includes a lumen (204a) formed therein, which is partially occupied by the inner assembly (206) positioned throughout the outer assembly (204) as illustrated in FIG. 3, and extends distally beyond the outer assembly (204).

[0045] The inner assembly (206) and the outer assembly (204) may each be composed of various combinations of polymer layers and metal reinforcing layers (e.g., metal coils or braids). In one example, each assembly (204, 206) utilizes multiple polymer layers. In one example, each assembly (204, 206) utilizes multiple polymer layers, and at least one of the assemblies (204, 206) may additionally utilize at least one metal reinforcing layer to provide additional structural strength. Different regions of the inner assembly (206) and the outer assembly (204) may be composed of different combinations of structural layers, for example, the more proximal region may use a stronger material (e.g., a harder polymer), while the more distal region may use a more flexible material (e.g., a softer polymer).

[0046] A cross-sectional view of a balloon catheter illustrating an inner (206) and outer (204) assembly is illustrated in more detail in FIG. 4. The inner assembly (206) includes a lumen (206a), which in one embodiment functions as a passage for a catheter in which a double lumen balloon (200) functions as a balloon guide catheter. The outer assembly (204) includes an expansion lumen (204a) formed in the space between the inner wall of the outer assembly (204) and the outer wall of the expansion lumen (204a), which represents an open space between the inner assembly (206) and the outer assembly (204).

[0047] The proximal end of the balloon catheter (200) comprises a hemostatic or y-shaped adapter (not shown) having two ports (each port forming a y-shaped branch), the first port communicating with an expansion lumen (204a) to deliver an expansion fluid (e.g., saline or contrast agent) distally to the balloon (202), and the second port communicating with an internal lumen or passage (206a) to deliver a substance through it (e.g., a catheter containing a medical device or a catheter serving as a passage for suction).

[0048] The distal portion of the inner assembly (206) utilizes a mechanism to prevent the balloon from adhering to the outer surface of the inner assembly (206). As shown in FIG. 3, the inner assembly (206) extends along the entire length of the balloon catheter (200), including the entire length of the balloon (202). The distal portion of the balloon catheter (200) is illustrated in more detail in FIG. 5, where the approximate location of the mechanism (208) is shown.

[0049] The balloon (202) is joined proximally to the outer assembly (204) at locations (202c, 202d)—this joining may be made on the outer surface of the outer assembly (204) (shown in FIG. 5) or along the inner wall of the outer assembly (204). The balloon (202) is joined distally to the inner assembly (206) at locations (202a, 202b) along the outer / outer surface of the inner assembly (206). As shown in the drawings, the balloon (202) does not inflate at these joining locations (202a-202d) because the balloon is joined to the inner (206) or outer (204) assembly (e.g., via adhesive) at these locations. In other words, a portion of the balloon (202) between these joining locations inflates or deflates, while the balloon (202) remains fixed and does not inflate at the joining locations (202a-202d).

[0050] The region (208) of the balloon catheter (200) is illustrated in more detail in FIGS. 6a-6b. The left side facing to the right is considered to be the proximal side facing to the distal side, and therefore the right side is considered to be the distal end of the balloon catheter. The membrane (210) is placed over the outer surface of the inner assembly (206). An elongated fuzzy passage or channel (212) is located within the structural layer or wall of the inner assembly (206) and further located beneath the membrane (210). A marker band (216) is located distally and includes a gap (216) to accommodate the channel (212).

[0051] The membrane (210) is positioned on and around the internal assembly (206). In one embodiment, the membrane (210) is a sheet of material having a circumference that is generally smaller (or similar) to the circumference of the internal assembly (206) when the ends of the sheet meet in a curled state. Consequently, the ends of the sheet may not be paired with each other when positioned on the internal assembly (206). This forms a gap between the two ends of the membrane (210) when positioned on the internal assembly (206). This gap forms an exposed area (218) of the internal assembly (206) that is not covered by the membrane (210). In one embodiment, the membrane (210) is placed on the internal assembly (206) and a portion of the membrane (210) is cut or removed to create an exposed area (218) of the internal assembly (206). The membrane (210) is bonded to the internal assembly (206), for example, through an adhesive or by the mechanism of a marker band (216) located over the distal portion of the membrane (210) according to one example.

[0052] Since the membrane (210) covers the periphery of a part of the internal assembly (206), the membrane (210) can also be considered, for example, as an upper layer (for example, a layer covering the periphery of a part of the internal assembly (206)), an upper element, a part of the periphery layer / element, a radial outer layer / element, and an outer layer / element.

[0053] The outer or external surface of the inner assembly (206) comprises an exposed area (218) (meaning not covered by the membrane (210)) and one or more elements (220) are located in this exposed area (218). The elements (220) consist of a roughened area, a projecting surface, or a recessed surface and serve to create a non-flat boundary surface to prevent the balloon from adhering when the balloon is in a deflated state. The created boundary surface prevents the balloon from adhering or sticking to the surface of the inner assembly (206) (e.g., along the exposed portion (218)).

[0054] FIG. 6a illustrates one view (e.g., top view) of a region (208) of a balloon catheter (200), in which an elongated fuzzy passage or channel (212) is located within the internal assembly (206) and beneath the membrane (210) along this top view. FIG. 6b illustrates another view (e.g., bottom view) of the region (208), in which an exposed region (218) and one or more elements (220) along this exposed region (218) are present, which will be described in more detail below. In one example, the channel (212) and the elements (220) are opposite each other by 180 degrees. In another example, they are offset from each other by a certain number of perimeter directions (e.g., 5-180 degrees or 90-180 degrees).

[0055] In one embodiment, the element (220) includes one or more indented, grooved, or recessed regions protruding from the surface of the internal assembly (206). These indentations can be made in various ways, for example, a wire or mandrel can be placed on the surface of the internal assembly (206) and heated along its length to be imprinted on the surface of the internal assembly (206) (e.g., through a soldering iron). The wire or mandrel is then drawn out and leaves an imprinted shape forming an indented, grooved, or recessed surface (e.g., see Fig. 6d). If multiple indented surfaces are created, this technique may utilize multiple wires spread around the exposed area (218) of the internal assembly (206). In one embodiment, an indented, grooved, or recessed area is created by a heating element passing along the surface of the internal assembly (206), thereby leaving a concave surface along the length of the heating element's path to the surface of the internal assembly (206). In one embodiment, the process of creating the indented area will move material from the indented area to an area adjacent to the indentation, thereby leaving an indentation and a raised area immediately adjacent to the indentation where the moved material moves.

[0056] In one embodiment, the element (220) includes one or more projecting regions that project outward from the surface of the internal assembly (206) (e.g., as shown in FIG. 6c). The projecting regions may be formed, for example, by using an additional amount of flux from a soldering iron to create a surface that projects along the path of the soldering iron.

[0057] In one embodiment, the indented or projecting area forms one or more continuous lines. In one embodiment, the indented or projecting area is essentially spiral (e.g., extending in a spiral or coil-like path along the surface of the internal assembly (206)). In one embodiment, the indented or projecting area is essentially spotted or point-shaped, where the indented or projecting surface is applied to local points along the surface of the internal assembly (206).

[0058] In some embodiments, various additional techniques such as deposition, 3D printing, and additional elements (e.g., elements attached to or physically attached to the outer surface of the inner assembly (206)) may be used to create a protruding surface. In some embodiments, techniques such as deposition, 3D printing, and reduction techniques (e.g., using pin elements or rigid elements to remove an outer area of ​​the inner assembly (206)) may be used to create an indented or recessed surface along the inner assembly (206).

[0059] FIG. 6c illustrates a cross-sectional view in which the membrane (210) is partially positioned around / on top of a portion of the internal assembly (206), leaving an exposed area (218), and further utilizes a surface (220a) protruding along the internal assembly (206). One or more protruding surfaces (220a) may be utilized along the exposed area (218). Additionally, the projection (220a) may be combined with a recessed, indented, or depressed surface (shown in FIG. 6d), where, for example, the projection surface may be positioned next to or adjacent to the indented, recessed, or depressed surface as shown in FIG. 6d—as shown in FIG. 6e and 6f.

[0060] FIGS. 6c-6e help to illustrate how protruding (220a) or recessed surfaces (220b) help prevent balloon adhesion. Without the inclusion of these elements (220a or 220b), the entire exposed portion (218) of the internal assembly (206) could potentially be in contact with a portion of the balloon (220), creating an extended area of ​​potential adhesion. However, the inclusion of the elements (220a or 220b) creates a roughened or uneven surface, reducing the total surface area that can be in contact with the balloon (200) in an uninflated state and thereby reducing the risk of the balloon becoming adhered or bonded. For example, if a raised surface (220a) is used, the balloon (200) in an uninflated state may only come into contact with the "top" portion of the raised surface (200a) and may have less contact with adjacent areas as the balloon "lifts" relative to the rest of the exposed surface (218). If an indented surface (220b) is used, the balloon (200) in an uninflated state may only come into contact with a portion of the "lifted" surface next to the indented surface (220b), but may not come into contact with the indented surface itself (220b). In other words, the inclusion of the element (220a or 220b) reduces the total surface area that can come into contact with the balloon (200) in an uninflated state, thereby reducing the risk of adhesion as the balloon (200) inflates.

[0061] In one example, a plurality of projections (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) are formed in equidistant spaces surrounding the distal portion of the inner assembly. In one embodiment, the projections are applied only along the exposed portion (218) of the inner assembly (206). One advantage of this configuration is that the manufacturing step of creating the projections needs to be applied only to the exposed portion (218) of the assembly (206) (i.e., the portion of the inner assembly (206) not covered by the membrane (210)), rather than the entire perimeter of the inner assembly (206), thereby facilitating the manufacturing and assembly process. In another embodiment, these projections are applied along the entire perimeter of the distal portion of the inner assembly (206), and the membrane (210) is placed over the inner assembly (206) where grooves are exposed only along the exposed portion (218).

[0062] FIG. 6d illustrates a cross-sectional view in which a membrane (210) is partially positioned around / on a portion of an internal assembly (206), leaving an exposed area (218), and further utilizes a recessed, indented, or depressed surface (220b) along the internal assembly (206). The surface (220b) may be considered a groove. One or more recessed, indented, or depressed surfaces (220b) may be utilized along the exposed area (218). Additionally, the recessed, indented, or depressed surface (220b) may be combined with a protruding surface (shown in FIG. 6c), wherein, for example, the protruding surface may be positioned next to or adjacent to the indented or recessed surface as shown in FIG. 6d.

[0063] In one example, a plurality of grooves (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) are formed in equidistant spaces surrounding the distal portion of the inner assembly. In one embodiment, these grooves are applied only along the exposed portion (218) of the inner assembly (206). One advantage of this configuration is that the manufacturing step of creating the grooves needs to be applied only to the exposed portion (218) of the inner assembly (206) (i.e., the portion of the inner assembly (206) not covered by the membrane (210)) rather than the entire perimeter of the inner assembly (206), thereby facilitating the manufacturing and assembly process. In another embodiment, these grooves are applied along the entire perimeter of the distal portion of the inner assembly (206), and the membrane (210) is placed over the inner assembly (206) where the grooves are exposed, only along the exposed portion (218).

[0064] In one embodiment, one or more longitudinal grooves / indented surfaces are formed along the outer surface of the inner assembly (206) by placing a metal mandrel or wire (70) along the surface of the inner assembly (206). The mandrel or wire is heated and pressed against the surface of the inner assembly (206) using a soldering iron. The soldering iron is moved down the length of the mandrel or wire to ensure uniform heating and depression into the inner assembly (206). Once the groove is formed, the mandrel is removed and repositioned to create another longitudinal groove on a different perimeter of the inner assembly (206) (if more than one groove is required).

[0065] Another embodiment of the element (220) may utilize one or more spot divots (i.e., indented, depressed, or recessed, or surface) or one or more spot projections created by placing a soldering iron or piercing element (e.g., a pin) over various parts of the internal assembly (206) to create a plurality of different surfaces or textures across the exposed portion (218) of the internal assembly (206).

[0066] Various embodiments presented for creating surface features on the surface of a catheter (e.g., grooves, indentations, ridges, projections, depressions, recesses, etc.) are used to create a non-smooth surface to prevent balloon adhesion or sticking. As such, these elements (e.g., grooves, indentations, ridges, projections, depressions, recesses, etc.) may be considered as surface features, roughened areas, surfaces with various shapes or profiles, or substantially non-smooth surfaces to achieve this goal. Additionally, if these elements protrude from the surface of the catheter (e.g., internal assembly 206), they may be considered as surface projections, surface ridges, etc. If these elements extend indented into the surface of the catheter (e.g., the inner assembly (206)), they may be considered as surface grooves, surface indentations, surface depressions, surface recesses, etc. In the manner described herein, surface features reduce the contact area between the inner part of the balloon (200) and the inner assembly (206) (e.g., the exposed part (218) of the inner assembly (206)), thereby reducing or eliminating the risk of balloon adhesion or bonding.

[0067] In one embodiment, the membrane (210) is non-sticky or substantially non-sticky so that the balloon cannot adhere to the membrane when it is in a contracted state. In one example, the membrane (210) is composed of expanded polytetrafluoroethylene (ePTFE). In this way, the balloon (202) is prevented from adhering to the surface of the internal assembly (206) by both the non-stickiness of the membrane (210) and the element (220) that prevents adhesion or sticking along the gap portion (218) not covered by the membrane (210). Since one of the factors affecting balloon adhesion is the relative softness of the material in contact with the balloon (202), it is preferable that the membrane (210) be composed of a material that is harder than the balloon (202).

[0068] In one embodiment, the membrane (210) extends for a length of about 1-50, 5-30, 5-15, 5-10, or about 7-8 millimeters from the distal tip of the inner assembly (206). In one example, the element (220) (e.g., protrusion (220a), depression (220b)) extends for a length of about 1-50, 5-30, 5-15, 10-15, or about 13 millimeters from the distal tip of the inner assembly (206). In these embodiments, the membrane (210) and the element (220) do not extend for the entire length of the balloon (202). One reason is that balloon adhesion is generally more of a problem in the distal region of the balloon. To improve the flexibility of the distal region of the catheter, the inner assembly (206) (described below) utilizes a soft polymeric element in the distal tip region that creates or contributes to potential adhesion problems. Additionally, the inner part of the balloon (202) (e.g., further from the bonding location (202a-202d) shown in FIG. 5) does not need to be placed directly or adjacent to the surface of the inner assembly (206) when the balloon is in a deflated state, which means that balloon adhesion or stickiness is a more significant factor along the distal region of the balloon (202).

[0069] In other embodiments, a membrane (210) and / or elements (220) may be used along the surface of an inner assembly (206) corresponding to substantially the entire length of the balloon (202) or a large portion of the balloon (202). If the membrane (210) and / or elements (220) are located along substantially the entire length of the balloon (202), this will correspond to the substantial entire length of the portion of the inner assembly (206) located distal to the outer assembly (204), since the balloon (202) is connected to the balloon (202) proximal to the outer assembly (204) and distal to the inner assembly (206)—as illustrated in FIG. 5.

[0070] The membrane (210) contains a number of pores (e.g., a large number of small pores to create a porous profile), and the pores provide another important function in that they allow gas to pass into the channel (212) below the membrane; accordingly, the channel (212) can be considered a purge channel or a de-airing channel. The pores of the membrane (210) are large enough for gas to pass into the channel below but too small for liquid to pass through. Accordingly, the membrane allows gas to pass through but retains liquid, which allows the user to de-air or de-gas the balloon before an endovascular procedure. To prepare the balloon for an endovascular procedure, the user sends an inflating medium (e.g., saline or contrast agent) to the balloon, where the inflating medium will replace the retained gas or air and be pushed out of the membrane and into the channel (212) through the pores. When the inflation medium begins to inflate the balloon, the user can see that all air or gas has been removed from the balloon, and the user pulls proximally against the syringe plunger or uses a vacuum system to extract the inflation medium from the balloon (202) again to deflate the balloon.

[0071] The channel (212) extends completely to the distal tip of the balloon catheter (200) (i.e., exits the distal tip of the internal assembly (206)), and thus the channel (212) allows gas or air to be discharged distally from the balloon catheter (200) / balloon (202). In another example, the channel (212) ends at a location proximal to the distal tip, but the portion of the catheter internal assembly (206) using the channel (212) is thicker than the distal extremity of the internal assembly (206) lacking this channel (e.g., a small, concave distal tip portion is located distally to the portion using the channel (212), and accordingly, the channel (212) still discharges gas or air from the internal assembly (206).

[0072] In one example, the membrane (210) is an ePTFE layer with a thickness of about 0.0006"–0.0007" and a pore size of about 0.4–0.6 microns. Pores in this size range block the passage of liquids (e.g., saline solution or contrast agent) but allow the passage of air / gas. The membrane polymer can be processed in various ways to impart pores of an appropriate size to create the membrane. In one preferred embodiment, the polymer is heat-treated to make the polymer elastic, stretch the polymer to create multiple pores inside, and reheat to fix a specific stretched shape. In another embodiment, a chemical is used, and the chemical penetrates through the polymer to create the membrane. In yet another embodiment, an e-spun process can be used to create a spider-web-like structure with pores of an appropriate size. In yet another embodiment, the membrane is a porous foam material.

[0073] As described above, the membrane (210) (e.g., ePTFE) is substantially non-adhesive and may not adhere to the balloon material. The balloon (202) is preferably formed of a soft material useful for neurovascular applications. In one embodiment, the balloon (202) is formed of Polyblend 45A or other polymer elastomer material. The balloon (18) may have a diameter of approximately 15 millimeters or less and a length in the range of 5 to 50 millimeters, preferably in the range of 10 to 20 millimeters.

[0074] Two soft surfaces may have a tendency to adhere or stick to each other. The balloon catheter (200) includes a softer distal tip segment using a soft polymer material (e.g., low-density polyethylene, or low-hardness Pebax) at the distal tip segment of the inner assembly (206), which is located beneath the outer surface of the inner assembly (206) and the membrane (210). The softer distal interface helps to improve flexibility along the distal portion of the balloon catheter (200). The membrane (210) (e.g. using ePTFE) is at least slightly harder than the soft polymer material beneath the inner assembly (206), and accordingly, the increased relative hardness of the membrane (210) reduces adhesion between the balloon (202) and the membrane. In addition, the pores of the membrane (210) create a number of small, non-uniform elements across the surface of the membrane (210), create a non-uniform surface, and further contribute to the non-stick properties of the membrane (210).

[0075] An additional advantage of using a softer distal tip segment in the internal assembly (206) (e.g., through low-density polyethylene or low-hardness Pebax distal elements) is that, since the distal tip of the internal assembly represents the distal end or distal end of the balloon catheter (200), the softer the tip, the less potential damage the balloon catheter (200) may cause to the blood vessel. As a result, the softer distal tip causes less trauma to the blood vessel.

[0076] FIG. 7 illustrates a different view of the distal portion of the balloon catheter (200) and illustrates the membrane (210) and the purge passage (212) in more detail, where the right side illustrates the more distal portion of the balloon catheter (200). The internal assembly (206) consists of a polymer inner liner (226) (e.g., PTFE) and a structural polymer layer (228) placed on top. The membrane (210) is positioned on the polymer layer (228), and the outer surface of the membrane (210) faces the inner surface of the balloon (202). In this way, when the balloon (202) is not inflated, the balloon rests on the membrane (210), and when the balloon (202) is inflated, it adopts the shape illustrated in FIG. 7. FIG. 7 illustrates that the distal region of the balloon (202) is joined to the distal portion of the membrane (210), where the balloon is joined proximally and distally as previously discussed (e.g., joined proximally to the distal portion of the outer assembly (204) and distally to the distal portion of the inner assembly (206)).

[0077] An elongated fuzzy passage or channel (212) is created by placing a thin mandrel rod within the polymer layer (228) during the assembly process. After assembly, the mandrel rod is removed, leaving the elongated passage (212) shown in FIG. 7. A membrane (210) is positioned over the polymer layer (228) (containing the elongated passage (212)). As described above, the membrane (210) surrounds the outside of a portion of the perimeter of the polymer layer (228) of the inner assembly (206), leaving a perimeter gap corresponding to the exposed portion (218) of the inner assembly (206), as shown in FIG. 6b-6d.

[0078] In one embodiment, the polymer layer (228) is a relatively soft material (e.g., low-density polyethylene or low-hardness Pebax), and thereby the addition of a harder membrane (210) (e.g., if the membrane (210) uses a higher hardness polymer or a higher density ePTFE molecular profile) or a higher density ePTFE molecular profile on the polymer layer (228) helps to alleviate any adhesion between the extremely compliant / soft balloon (202) and the internal assembly (206).

[0079] In one embodiment, the polymer layer (228) is a harder / rigider polymer (e.g., high-density polyethylene or high-hardness Pebax) and an additional soft material layer (e.g., low-density polyethylene or low-hardness Pebax) is placed over this layer along the distal segment of the inner assembly (206) (e.g., along the segment of the inner assembly (206) below the membrane (210)) to increase flexibility along the distal region of the inner assembly (206) to increase traceability of the balloon catheter (200).

[0080] FIG. 7 also illustrates a purge port (224) that acts as a conduit between the balloon and the purge passage or channel (212). The port (224) functions as a conduit for gas exiting the balloon as the balloon passes through the pores of the membrane (210) and then proceeds into and through the purge passage (212).

[0081] The above-described embodiment (e.g., illustrated in FIG. 6b) describes the use of an element (220) within an exposed portion of an internal assembly (206) not covered by a membrane (210) to provide a mechanism to prevent balloon adhesion or bonding, particularly in an area not covered by the membrane (210). As described above, the element (220) may take various configurations including a raised surface or a projection surface, an indentation / groove / depressed / recessed surface, etc. Other embodiments of these elements (220) may utilize different configurations to create a roughened, unsmooth, or uneven shape to resist balloon adhesion to the surface. In one embodiment, a coil (e.g., a metal coil shape) is placed on the outer surface of the inner assembly (206) and subsequently removed to imprint the coil shape. The coil leaves a linear circular imprint or spiral groove at the position where it was placed. This creates a roughened and imprinted or recessed shape in the area where the coil was previously located, and creates a raised or protruding surface in the adjacent area (raised relative to the area where the coil was located). In another embodiment, a braid may be used to create a more complex imprinted surface shape. Due to the inclusion of the upper membrane (210) (where only a portion (218) of the inner assembly (206) is exposed), the element (220) is located not only under the membrane (21) but also along the exposed portion (218) of the inner assembly (206)—however, since the element (220) is only exposed, it provides a functional advantage of reducing adhesion or tackiness along the exposed surface (218).

[0082] In one embodiment, a wire is wrapped around the outer surface of an inner assembly (206) and heated. Then, a heat-shrink tubing is placed around the wiring and heat is applied so that the tubing shrinks over the wire, thereby pressing the heated wire outward from the inner tubular element to form a number of grooves. When cooled, the shrink wrap is separated from the inner assembly (206) and the wire is removed, leaving a number of grooves. A membrane (210) is then positioned over a portion of the inner assembly (206), leaving an exposed grooved surface positioned over an exposed gap area (218).

[0083] In one embodiment, a braided mesh tube may be used in a similar manner to form a different pattern. The distal end of the inner assembly (206) is placed within the braided tube, the tube is stretched to reduce the diameter around the inner assembly (206), and the tube is heated to a temperature that softens the catheter material. A separate heat shrink tube may be applied to press the braided tube into the catheter to create a patterned impression on the outer surface of the inner assembly (206). The membrane (210) is positioned over a portion of the inner assembly (206), as described above.

[0084] Another embodiment may use a membrane (210) placed around the entire periphery of the distal portion of the inner assembly (206) (e.g., without an exposed area (218) of the inner assembly (206) by this). The non-adhesiveness of the membrane (210) to the inner surface of the balloon (202) will prevent balloon adhesion.

[0085] Other embodiments may completely exclude the use of a membrane (210). Instead, longitudinal grooves / depressions, longitudinal protrusions, spot divots, spot protrusions, spiral grooves, spiral protrusions, etc., as discussed in the embodiments presented above, are arranged to surround the outer portion of the inner assembly (206). One advantage of a system in which a membrane is not used and instead one or more longitudinal grooves or depressions are arranged to surround the inner assembly (206) is that if these grooves or depressions extend over a significant length of the balloon (202), they can be used to help create a more uniform or consistent inflation process by delivering an inflation fluid (e.g., a contrast agent or agent) to the distal portion of the balloon (202). The grooves or depressions (e.g., 220b) leave a channel surface that allows the passage of the inflation fluid, where as more inflation fluid is added to the balloon, the inflation fluid is pushed distal and ensures a more uniform inflation profile, particularly along the distal portion of the balloon. In one example, during the preparation procedure for removing air from the balloon, the inflating medium initially pushes air out of the balloon through the balloon and into the purge passage (212) (as previously described and illustrated in FIG. 6a). The depression may also create a channel for air to be pushed up to the purge passage (212) and membrane of the balloon catheter (200) to be purged from the balloon.

[0086] This concept is illustrated in FIGS. 6g-6i, where a membrane is not used and different combinations of protrusions (220a) and depressions (220b) are used. Although a straight shape is illustrated, in some embodiments (including the use of a membrane (210)), the shape may be essentially round or pointed. A more pointed shape (220a, 220b) is illustrated in FIG. 6j. FIG. 6k illustrates a plurality of spot protrusions (220a) and spot divots / depressions (220b) randomly spread across the surface of the inner assembly (206). FIG. 6l illustrates the above-described configuration in which a coil (236) is initially placed on the surface of the inner assembly (206) and then removed, leaving a spiral groove / depression along the surface of the inner assembly (206) that reflects the placement of the coil (236).

[0087] Here, even when the membrane (200) is used (thus, the protruding area (220a) or the recess (220b) has a functional advantage along the exposed portion (218) of the internal assembly (206), the recess (220b) will still have an advantage in providing a channel for an air passage during the air purging step and a channel for an expansion fluid passage distally along the exposed area (218) of the internal assembly (206), and thus will also provide such procedural advantages.

[0088] The above examples described various mechanisms for reducing balloon adhesion in balloon catheters. In some examples, these mechanisms are used as part of a balloon guide catheter.

[0089] The background technology described the various challenges of balloon guide catheter design and the advantages of such systems. Currently, balloon catheters are delivered via upper guide catheters. When used for neurovascular procedures or interventions in or near the carotid artery, the guide catheter must be able to navigate the carotid siphon, which is a highly curved U or S-shaped bend, ideally in the carotid artery or the more distal portion of the internal carotid artery.

[0090] The carotid siphon provides access to the neurovascular system. If the guide catheter lacks sufficient flexibility to navigate the carotid siphon, it becomes unable to navigate this bend, and a smaller procedure catheter (e.g., a microcatheter, a distal access catheter, or a procedure balloon catheter) may be left unshielded when navigating the target treatment site.

[0091] The guide catheter is important because it is larger and rigid to support the smaller procedure catheter, but it must also be flexible enough to navigate tortuous anatomical structures such as the carotid siphon. While possessing sufficient flexibility to navigate the carotid siphon, the guide catheter must also be strong enough not to bend due to the curved and pulsating nature of the vascular structure, and strong enough to support the smaller catheter delivered through it.

[0092] The use of a balloon guide catheter can be particularly advantageous because the balloon guide catheter can be used as a support structure and can be accessed through a passage to a smaller procedure catheter (e.g., a microcatheter, a distal-access catheter, or a balloon catheter for a smaller procedure—where the smaller catheter delivered through the balloon guide is used as a conduit for medical devices, delivering therapeutic substances, or for aspiration / suction). The balloon guide can be used to provide proximal flow stop at the procedure site, for example, to provide proximal flow stop to restrict blood flow to the treatment site, after the smaller procedure catheter has been placed through the lumen of the balloon catheter.

[0093] Balloon guide catheters can be particularly advantageous for certain procedures. For example, in the case of aspiration procedures or thrombectomy procedures used to recover blood clots, a balloon guide catheter can be used to provide a proximal seal (via the balloon) to restrict blood flow to the treatment site as the clot recovery procedure takes place. The internal passage of the balloon guide catheter is used as a passage for a smaller catheter (e.g., a microcatheter or distal-access catheter) that serves as the aspiration conduit, or for the thrombectomy device performing the procedure.

[0094] FIG. 8 illustrates an example in which a balloon guide catheter (300) is used to deliver a mechanical thrombectomy device. As understood by those skilled in the art, the properties of the embodiments discussed above may be applied to other systems including balloon guide catheters, for example, as disclosed in this document.

[0095] The passage (306a) of the internal assembly (306) is used as a passage for a procedure catheter (330) (e.g., a microcatheter) containing a thrombectomy device (334) for a smaller procedure catheter (330) (e.g., the microcatheter of the example in FIG. 8). In one example, the thrombectomy device (334) is configured like a stent but is a stent-type device also known as a stenter used for thrombus capture, and includes an open end sized to capture a clot or thrombus and a closed proximal end connected to a delivery pusher (332) used to deliver the device to the treatment site (i.e., to push the thrombectomy device (334) out of the microcatheter (330)). The balloon (302) may be inflated during the delivery procedure (as shown in FIG. 8), or after the procedure catheter (330) (e.g., a microcatheter) and the thrombectomy device (334) have been delivered to the treatment site to perform a blood clot / thrombus recovery procedure. In one example, the thrombectomy device comprises a plurality of fastening members used to fasten blood clots or thrombi, such as the device described in U.S. Patent No. 9,211,132, the whole of which is incorporated herein by reference.

[0096] In one embodiment, the procedure catheter (330) acts as a suction conduit, and a suction / vacuum source (e.g., a vacuum pump) is connected in close proximity to the procedure catheter (330) to suction blood clots / thrombus at the treatment site. The balloon guide catheter (300) is navigated through (and optionally through) at least a portion of the carotid siphon to access the area of ​​the neurovascular system. The procedure catheter (330) (e.g., a microcatheter, a distal access catheter, or a smaller balloon catheter) is navigated through the internal passage (306a) of the balloon guide catheter (300) to the target treatment site. The balloon (302) of the balloon guide catheter (300) is inflated to provide proximal flow stoppage and restrict blood flow to the target treatment site, and the procedure catheter (330) is used to perform a suction procedure so that blood clots or thrombi are sucked or aspirated into the procedure catheter (330).

[0097] The above example is used exemplarily because various devices, such as vascular-occlusion coils, liquid embolisms, embolisms or drug-containing beads / microspheres, and embolism mesh stents, can be delivered through the procedure catheter (330). In one example, the procedure catheter (330) is a smaller balloon catheter delivered through the balloon guide catheter (300) that can provide proximal flow stop near the carotid siphon, whereas the smaller balloon catheter delivered through the balloon guide catheter (300) can provide flow stop closer to the treatment site.

[0098] Some of the examples described above illustrate the use of proximal flow blockage through the balloon (302) of the balloon guide catheter (300). This is useful for several reasons. Inflating the balloon (302) fills or occludes the area around the catheter (300) with the inflated balloon, acting as a flow barrier for blood flowing distally. While the balloon guide catheter (300) is placed proximal to the treatment site (e.g., near the carotid artery, e.g., to or around the carotid siphon), the procedure catheter (330) at the treatment site, where the balloon (302) of the balloon guide catheter (300) is inflated, helps to restrict blood flow to the target treatment site. This restricted blood flow is useful, for example, in preventing the clot / thrombus from moving to a more downstream location during a retrieval procedure (e.g., when the clot or thrombus may fragment during aspiration or retrieval by a mechanical thrombectomy device). In this way, flow cessation helps prevent blood clots or thrombi from moving or moving further downstream during the recovery procedure.

[0099] Stopping flow through the inflation of the balloon (302) of the balloon guide catheter (300) is also useful in other procedures. For example, the balloon guide catheter (300) itself can be used for aspiration, where the internal assembly (306) functions as a conduit for aspiration / vacuum through which the aspiration is delivered via the internal assembly passage (306a). This procedure can be used, for example, when a blood clot or thrombus is located proximal or slightly distal to the carotid artery siphon, in contrast to more distal and smaller neurovascular regions (e.g., where the balloon guide catheter (300) can be easily tracked). In this way, the balloon (302) can provide an immediate proximal flow barrier for the aspiration procedure, where the aspiration procedure takes place using the balloon guide catheter (300) itself.

[0100] In other procedures where the procedure catheter (330) is delivered via the balloon guide catheter (300) for other purposes (e.g., delivery of a vascular-occlusive coil or mesh, delivery of a liquid embolus, delivery of an embolus / drug-containing bead, etc.), the balloon (302) provides proximal flow cessation at the treatment site and helps prevent blood from pushing away the therapeutic material delivered via the procedure catheter (330) during the delivery procedure. In this way, the balloon (302) is selectively inflated during the procedure, whereby after the therapeutic material is delivered via the procedure catheter (330), the procedure catheter (330) is deflated into the balloon guide catheter (330), the balloon (302) of the balloon guide catheter (300) is deflated, and the balloon guide catheter (300) is withdrawn from that position.

[0101] The necessary characteristics of a properly functioning balloon-guided catheter have been described previously. They must possess sufficient flexibility to pass through more curved vascular structures (e.g., carotid siphons) and be strong enough to serve as a passage for smaller catheters (e.g., microcatheters and distal access catheters) delivered through the balloon guide.

[0102] The additional mechanism required for a balloon catheter (e.g., expansion lumen, balloon) can significantly increase the rigidity of the balloon guide catheter compared to a conventional guide catheter, and poses a unique design problem in that the balloon guide catheter may need to be much rigider than a conventional guide catheter because it includes the balloon and the material required for balloon inflation. To reduce the rigidity of the balloon guide catheter and increase its flexibility, specific features can be utilized. For example, the inclusion of a softer polymer segment at the distal end of the balloon catheter, such as low-density polyethylene or low-hardness Pebax, as discussed in the previously presented examples. However, including a softer system may cause the balloon to become adhesive (e.g., because the balloon (302) itself is soft). Therefore, to alleviate the balloon sticking problem, the use of the mechanism described in the embodiment (e.g., some configurations shown in FIG. 6a-6c) (e.g., through the use of a membrane (210) and an element (220) positioned along the surface of the internal assembly (206)) helps to make the assembly (206) a usable balloon guide catheter.

[0103] In one embodiment, the balloon guide catheter (300) has an outer diameter of about 0.09 inches to 0.12 inches and includes an inner assembly having an inner diameter of about 0.08 inches to 0.09 inches (meaning the size of the passage (306a) of the inner assembly (306)) so as to accommodate a catheter smaller than the inner diameter of the inner assembly. The indicated size is useful for a specific target vascular area (e.g., exploration of the carotid siphon area of ​​the vascular system), but the size of the balloon guide catheter can be increased or decreased as needed.

[0104] The passage (306a) of the internal assembly (306) of the balloon guide catheter (300) has a specific function of being used as a conduit for a procedure catheter (330) (e.g., a smaller catheter such as a microcatheter or a distal access catheter) that can be used to deliver a subsequent item (e.g., a medical device, aspiration, therapeutic material, etc.). In one example, the procedure catheter (330) is a distal access catheter and is subsequently used as a conduit for a smaller catheter (e.g., a microcatheter) that is used for delivering a subsequent item (e.g., a medical device, aspiration, therapeutic material, etc.). In one example, the distal access catheter itself is used for delivering a subsequent item (e.g., a medical device, aspiration, therapeutic material, etc.).

[0105] In one example, the passage (306a) of the internal assembly (306) of the balloon guide catheter (300) is initially used as a conduit for a guidewire, which is a small access wire used to guide the guide catheter to the vicinity of the treatment site (e.g., the carotid siphon area). In one example, the balloon guide catheter is fixed distally to the carotid siphon or beyond, the guidewire is navigated through this area to the treatment site, and the procedure catheter (330) is navigated to the treatment site via the guidewire. Then the guidewire is removed.

[0106] In various embodiments, a method of use or a method of procedure is described. In one embodiment, the method comprises the action of a user tracing a balloon guide catheter through at least a portion of the carotid siphon region of the vascular system; the action of positioning a procedure catheter (e.g., a microcatheter or a distal access catheter) to a treatment site through an internal assembly or internal passage of the balloon guide catheter and the distal portion of the balloon guide catheter; the action of inflating the balloon of the balloon guide catheter to provide flow stop near the target treatment site; and the action of performing a procedure using the procedure catheter. In various embodiments, the procedure may be aspiration, mechanical thrombectomy, or embolization delivery in which the procedure catheter is a conduit for aspiration, a mechanical thrombectomy device, or embolization material. The mechanical thrombectomy device may be a thrombus recovery device or a stentriever. The embolization material may include a liquid embolus, an embolization mesh, or an embolus / vascular-occlusion coil. In one embodiment, the method comprises the action of further tracking a guidewire through an internal passage of a balloon guide catheter, the action of using the guidewire to guide the balloon guide catheter to a specific location, and the action of subsequently using the guidewire to guide the procedure catheter to a treatment location (e.g., when the treatment location is distal from the balloon guide catheter location). When the guidewire reaches the target treatment location, it is pulled.

[0107] In one embodiment, the method comprises the action of navigating or tracking a balloon guide catheter through at least a portion of the carotid artery siphon region of the vascular system, the action of inflating a balloon in the balloon guide catheter, and the action of using the internal passage of the balloon guide catheter to perform a vascular procedure. In one embodiment, the vascular procedure is aspirating, suction, or vacuum aspirating a clot or blood clot delivered through the internal passage of the balloon guide catheter.

[0108] As described above, balloon guide catheters are particularly useful for navigating curved bends, such as the carotid siphon of the internal carotid artery. Since the carotid siphon connects to the neurovascular artery, it is a curved or bent section that must be navigated to access the neurovascular system. The internal carotid artery consists of several segments. From proximal (away from the neurovascular system) to distal (toward the neurovascular system), these segments consist of the cervical segment (C1), petrous segment (C2), lacerum segment (C3), cavernous segment (C4), clinoid segment (C5), ophthalmic segment (C6), and communicating segment (C7). The carotid siphon is located along the distal portion of the cavernous segment (C4), where the clinoid segment (C5) is located distal to the carotid siphon.

[0109] In describing a balloon-guided catheter capable of navigating the carotid siphon, this implies that it can be moved into the carotid siphon region through the cavernous segment, thus allowing movement through at least the cavernous segment of the internal carotid artery or the C4 segment. Depending on the size of the vessel and the relevant flexibility of the balloon-guided catheter (e.g., various embodiments described for methods to increase flexibility), the user can guide the balloon-guided catheter to a more distal region, such as the clinoside C5 segment or more potentially the ophthalmic C6 segment and connecting segment C7. In other words, the balloon-guided catheter can potentially be used in a more distal region of the vascular system. Similarly, the embodiments presented herein can be scaled up or down as needed to create a balloon-guided catheter or balloon catheter capable of operating in larger or smaller arteries.

[0110] In some examples, the balloon guide catheter (300) may be used procedurally within other segments of the internal carotid artery, such as the C1-C4 segment.

[0111] As described above and disclosed in this document, the method of use can be understood as exploring various regions of a vascular structure such as the internal carotid artery, as well as the action of exploring a relevant segment of the internal carotid artery to place a balloon guide catheter. In this way, when the user places a balloon guide catheter or a balloon catheter through at least a portion of the carotid siphon, this involves the action of exploring the catheter through the C1-C3 segment and, since the carotid siphon is located along this C4 segment, at least a substantial portion of the cavernous C4 segment.

[0112] In one embodiment, a method for performing a vascular procedure includes the action of navigating a balloon guide catheter through the internal carotid artery through the cavernous segment of the internal carotid artery through at least a portion of a carotid artery siphon, the action of inflating the balloon, and the action of performing a vascular procedure using the internal passage of the balloon guide catheter. In one embodiment, the procedure further includes the action of passing a procedure catheter through the internal passage of the balloon guide catheter and the action of performing a procedure (e.g., device delivery or aspiration) using the procedure catheter. In one embodiment, the procedure includes the action of using the internal passage of the balloon guide catheter for aspiration near the balloon guide catheter. In one embodiment, the actions disclosed herein may also be used with a balloon catheter. In one embodiment, the balloon guide catheter or the balloon catheter uses an element (e.g., a membrane (210) and / or an element (220)) that reduces balloon adhesion. In one embodiment, as described herein, the method is used to perform a procedure along another segment of the internal carotid artery (e.g., C1, C2, or C3, C5, C6, or C7 segments). When the procedure is performed distally beyond the cavernous C4 segment (e.g., C5-C7 segments), the procedure includes the action of fully traversing the catheter through a carotid siphon. In some embodiments, a balloon guide catheter or balloon catheter may be traversed through any curved region of the vascular system using the method described herein, wherein the catheter may be sized and intended accordingly (e.g., to a sufficient level of strength and flexibility).

[0113] Here, where the carotid siphon leads to the neurovascular system, a balloon guide catheter can navigate the carotid siphon and provide flow stoppage (via the inflated balloon), and the passage of the balloon guide catheter is used as a conduit for a procedure catheter (e.g., a microcatheter or a distal access catheter) used to perform the procedure. In one example, the procedure catheter (e.g., a distal access catheter) is used to perform aspiration in a more distal region of the neurovascular system (meaning distal to the location of the balloon guide catheter), where the inflated balloon of the balloon guide catheter helps perform the procedure by reducing blood flow to the target site. In one example, the passage of the balloon guide catheter itself is used to perform the aspiration procedure near the balloon guide catheter. This latter example is useful when there is a blood clot or thrombus in an area that can be explored by a balloon-guided catheter (e.g., the C1-C5, C3-C5, or C4-C5 segments of the internal carotid artery).

[0114] While the explanation here focuses primarily on methods to reduce stickiness and how to apply these concepts to create usable balloon guide catheters, these concepts can be applied to other balloon catheters (e.g., not just balloon guide catheters) to create more useful balloon catheters. As such, the described balloon catheters can be scaled larger or smaller as needed by incorporating the ideas presented here for use in various scenarios.

[0115] Although the present invention has been described in terms of specific embodiments and applications, those skilled in the art may make additional embodiments and modifications without departing from the spirit of the claimed invention or exceeding the scope of the claimed invention in light of such teachings. Accordingly, it should be understood that the drawings and descriptions in this specification are provided as examples to facilitate understanding of the invention and should not be interpreted as limiting the scope of the invention.

Claims

Claim 1 A balloon catheter comprising: an outer assembly including an expansion lumen; an inner assembly extending along the length of the outer assembly and extending distally past the outer assembly; a balloon connected proximally to the outer assembly and distally to the inner assembly; the balloon communicating with the expansion lumen of the outer assembly; a layer disposed on a distally portion of the inner assembly, wherein the layer is partially located around the distally portion of the inner assembly and the inner assembly comprises an exposed portion not covered by the layer; the exposed portion of the inner assembly comprises one or more surface projections or surface indentations, and the layer comprises a plurality of pores of a size that allows the passage of gas but blocks the passage of liquid. Claim 2 A balloon catheter according to claim 1, wherein one or more surface protrusions or surface depressions extend longitudinally along the exposed portion of the internal assembly. Claim 3 A balloon catheter in paragraph 2, wherein one or more surface protrusions or surface depressions extend longitudinally beyond the exposed portion of the internal assembly. Claim 4 A balloon catheter according to claim 1, wherein the one or more surface protrusions or surface depressions include one or more grooves, and the one or more grooves are arranged longitudinally around the perimeter of the internal assembly. Claim 5 A balloon catheter according to claim 1, wherein one or more surface protrusions or surface depressions extend in a manner that surrounds the exposed portion of the internal assembly. Claim 6 A balloon catheter according to claim 1, wherein the one or more surface protrusions or surface depressions comprise one or more elevations located along the outer part of the inner assembly. Claim 7 In claim 6, the exposed portion of the internal assembly comprises one or more surface protrusions and one or more surface depressions, wherein the one or more surface protrusions are adjacent to the one or more surface depressions, a balloon catheter. Claim 8 A balloon catheter according to claim 1, wherein the layer is substantially a non-sticky membrane. Claim 9 A balloon catheter according to claim 1, wherein the one or more surface protrusions or surface depressions comprise one or more depressions located along the outer part of the internal assembly. Claim 10 delete Claim 11 delete Claim 12 A balloon catheter comprising: an outer assembly including an expansion lumen; an inner assembly extending distally over the length of the outer assembly and extending distally through the outer assembly; a balloon connected proximally to the outer assembly and distally to the inner assembly; the balloon communicating with the expansion lumen of the outer assembly; a layer disposed on a distally portion of the inner assembly, wherein the layer is partially located around the distally portion of the inner assembly and the inner assembly comprises an exposed portion not covered by the layer; the exposed portion of the inner assembly comprises one or more surface projections or surface indentations, wherein the layer is radially disposed outside an elongated purge passage, and the elongated purge passage is disposed within the inner assembly and configured to discharge gas from the balloon. Claim 13 A balloon catheter comprising: an outer assembly including an expansion lumen; an inner assembly extending distally over the length of the outer assembly and extending distally through the outer assembly; a balloon connected proximally to the outer assembly and distally to the inner assembly; the balloon communicating with the expansion lumen of the outer assembly; a layer disposed on a distally portion of the inner assembly, wherein the layer is partially located around the distally portion of the inner assembly and the inner assembly comprises an exposed portion not covered by the layer; the exposed portion of the inner assembly comprises one or more surface projections or surface indentations, and the balloon is joined proximally to an outer surface or along an inner wall of the outer assembly. Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete Claim 24 delete Claim 25 delete Claim 26 delete Claim 27 delete Claim 28 delete Claim 29 delete Claim 30 delete Claim 31 delete Claim 32 delete Claim 33 delete Claim 34 delete Claim 35 delete Claim 36 delete Claim 37 delete Claim 38 delete Claim 39 delete Claim 40 delete Claim 41 delete Claim 42 delete Claim 43 delete Claim 44 In claim 1, the balloon is a balloon catheter distally bonded to the outer surface of the inner assembly. Claim 45 A balloon catheter according to claim 1, wherein the balloon is attached proximally to the outer assembly at the first and second positions, the balloon is attached distally to the inner assembly at the third and fourth positions, and the balloon is not inflated at the first position, the second position, the third position, and the fourth position. Claim 46 A balloon catheter according to claim 1, wherein one or more surface depressions are formed as coils or meshes that are imprinted on the surface of the internal assembly.

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