Balloon catheter with improved properties

Abstract

Balloon catheters are described with features that ensure a more uniform inflation shape by reducing balloon sticking. In some embodiments, balloon guide catheters are described with conduits or passageways for additional catheters or devices.

Description

Related Applications

[0001] This application claims priority to U.S. Provisional Application No. 62 / 934,423, filed November 12, 2019, entitled Non-Stick Balloon Catheter, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Balloon catheters can be used for a variety of procedures in the vascular system, including blood flow arrest, blood flow reversal, and occlusion, and serve as a framework for subsequently delivered medical devices, as well as part of an aspiration or clot retrieval procedure that stops blood flow to prevent a clot or thrombus from detaching from the target area during the retrieval procedure. Some balloon catheters are configured for neurovascular applications, and these balloon catheters are small in size to pass through the smaller blood vessels in that area, and the associated balloons generally need to be very soft or malleable to prevent vessel damage and to conform to the shape of the vessel.

[0003] Balloon catheters, particularly dual lumen balloon catheters, tend to encounter problems where the uninflated balloon unintentionally adheres or sticks to portions of the catheter (e.g., the internal guidewire lumen or passageway) during inflation. This phenomenon is more pronounced when the balloon is very soft, i.e., highly compliant, a common feature of balloons used in neurovascular applications due to the small size of the vessels and increased flexibility required to reach these smaller, more distally located vessels.

[0004] Such sticking or undesired adhesion can result in incomplete inflation of the balloon, causing the inflated balloon to have an asymmetrical or incompletely inflated shape within the patient's vessel being treated, thereby potentially limiting the effectiveness of the therapeutic procedure. For example, during a blood flow stasis procedure (e.g., when blood flow is stasis proximally to assist in performing the procedure), if the balloon is not completely filled, blood can still reach the treatment site, making the procedure more difficult. In one example, a balloon can be used as part of an aspiration or mechanical clot retrieval procedure, in which the balloon is used for proximal blood flow stasis to help ensure that clots or thrombi do not migrate downstream during the procedure. However, balloon sticking can result in the balloon having an incomplete shape, which prevents blood flow stasis from functioning as intended and can result in the clot or thrombus migrating or being expelled downstream.

[0005] A physician may attempt to correct such a problem by attempting to reduce the asymmetry or by overfilling the balloon with additional inflation medium to force the balloon into its fully inflated shape, but this can result in excessive pressure being applied, potentially causing vascular trauma to the patient or causing the balloon to burst.

[0006] One possible way to avoid such problems is to use a stiffer balloon material to reduce the balloon's compliance / flexibility. However, one major drawback is that stiffer balloons are less compliant and therefore less adaptable to complex vascular geometries, which may cause vascular trauma. Such balloons may also cause complications in certain small vessels (e.g., those in the neurovasculature).

[0007] Additionally, stiffer materials can affect the trackability of the balloon catheter, making it more difficult to navigate around tortuous bends. For example, balloon catheters used in neurovascular procedures typically must navigate through the carotid siphon, a U- or S-shaped bend in the carotid artery. It may be desirable to use a balloon catheter to access the cerebral vasculature beyond the carotid siphon during intravenous procedures such as vascular occlusion, aspiration, blood flow reversal, and clot retrieval. However, constructing a balloon catheter that is flexible enough to navigate through tortuous bends (e.g., the carotid siphon) can be challenging, especially when the need for a soft, or compliant, balloon can create potential balloon sticking issues.

[0008] Therefore, there is a need for a balloon catheter that can balance at least these requirements, namely, flexibility to navigate through tortuous bends and the ability to use a soft or compliant balloon that does not stick to the catheter.

[0009] Many medical procedures utilize a guide catheter as a conduit for a smaller catheter (e.g., a microcatheter) used to access the area of ​​interest or to deliver a therapeutic device used in the procedure. The guide catheter is larger and more rigid than the smaller catheter that is delivered therethrough, and the guide catheter is intended to act as a support structure for the smaller catheter / device that is delivered therethrough. An ideal guide catheter would be flexible enough to navigate through tortuous anatomical structures (e.g., the aforementioned carotid siphon), yet strong enough to withstand the pulsatile pressures of the anatomy and provide sufficient structural strength to support the placement of the smaller catheter or device therethrough.

[0010] For example, balloon guide catheters with balloons capable of providing proximal blood flow arrest to supplement therapeutic procedures (e.g., aspiration or clot retrieval by mechanical thrombectomy) and with passageways large enough to accommodate catheters or additional medical devices may offer significant advantages. However, these devices can be difficult to construct. For example, the inclusion of a balloon significantly increases the complexity of the guide catheter by requiring a separate inflation lumen and balloon, and the additional components can dramatically increase the stiffness of the guide catheter. This increased stiffness can impair the guide catheter's trackability through tortuous anatomical structures such as the carotid siphon. Additionally, while the use of flexible / compliant balloons (e.g., in neurovascular spaces) offers the advantage of not damaging the vessel wall when inflated, such balloons can also suffer from sticking or adhesion issues, as discussed above.

[0011] Furthermore, these catheters require a balance of flexibility and stiffness / strength. If the balloon guide catheter is too stiff, it will be unable to navigate tortuous anatomical structures (e.g., the carotid siphon) and will therefore ultimately be placed too far from the desired destination to achieve any benefit (e.g., too far to achieve optimal blood flow arrest for the clot retrieval procedure). This distance can also create complications, as the physician may have to track the clot proximally over a longer distance into the guide catheter, increasing the risk that the clot may fragment or migrate during the retrieval procedure. On the other hand, if the balloon guide catheter is too flexible, it may not be stiff enough to provide support for smaller catheters or therapeutic devices delivered through the balloon guide catheter's lumen, preventing the physician from completing the procedure.

[0012] Therefore, there is a need for a balloon guide catheter that can balance at least these requirements: flexibility to navigate through tortuous bends, the ability to use a soft or compliant balloon that does not stick to the catheter, and sufficient structural strength for the catheter or device being delivered through the passage of the balloon guide catheter. Summary of the Invention

[0013] In one embodiment, a balloon guide catheter is provided that utilizes an inner assembly that serves as a passageway for subsequently delivered therapeutic or procedural devices / substances (e.g., guidewire, catheter, thrombectomy device, suction / suction, embolic coil, and / or liquid embolus) and an outer assembly that delivers inflation fluid to the balloon. In one embodiment, the inner assembly of the balloon guide catheter provides a passageway for a smaller catheter that is used as a conduit for subsequently delivered therapeutic or procedural devices / substances (e.g., thrombectomy device, suction / suction, embolic coil, liquid embolus, embolic mesh, embolic or drug-containing beads, smaller procedural balloon catheter, etc.).

[0014] In one aspect, a balloon guide catheter is provided with a compliant balloon and a balloon anti-sticking mechanism that can be applied to balloon guide catheters as well as balloon catheters of various sizes and capabilities as a way to prevent the problem of balloon sticking.

[0015] In one embodiment, the feature is one or more grooves disposed along an outer portion of the balloon catheter inner assembly. In one embodiment, the one or more grooves are disposed longitudinally around the outer circumference of the balloon catheter inner assembly. In one embodiment, the one or more grooves are disposed circumferentially around the outer circumference of the balloon catheter inner assembly. In one embodiment, the one or more grooves are disposed helically around the outer circumference of the balloon catheter inner assembly.

[0016] In one embodiment, the features are one or more ridges disposed along the outer portion of the inner assembly of the balloon catheter. In one embodiment, the one or more ridges are disposed longitudinally and / or radially. In one embodiment, the one or more ridges are spot-like ridges or spot-like protrusions disposed at multiple locations along the outer portion of the inner assembly of the balloon catheter.

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

[0018] In one embodiment, the features are one or more radially oriented ridges / protrusions or depressions / indentations / grooves disposed along the inner assembly of the balloon catheter. In one embodiment, the radially oriented ridges or grooves are formed by helical elements. In one embodiment, the radially oriented ridges or grooves are created by mesh elements.

[0019] In one aspect, the balloon guide catheter utilizes a membrane on the distal portion of the balloon catheter that is substantially non-adhesive to prevent balloon sticking. In one aspect, the membrane includes a gap or cutout portion such that a portion of the underlying balloon catheter surface is exposed, and a balloon sticking prevention mechanism (such as those described above) is applied along the exposed balloon catheter surface to help prevent balloon sticking.

[0020] In one aspect, the balloon guide catheter employs a membrane at the distal portion of the balloon catheter and a purge or relief passageway below or radially adjacent to the membrane within the inner assembly of the balloon guide catheter, which provides an escape route for gas from the balloon. In one aspect, the membrane has pores sized to allow the passage of gas but not liquid (e.g., an inflation medium such as contrast or saline) to maintain the balloon in an inflated state by allowing gas to pass through the balloon while preventing the passage of liquid.

[0021] In one embodiment, a balloon guide catheter for performing procedures around the carotid artery is provided. In one embodiment, a balloon guide catheter for performing procedures around the internal carotid artery is provided. In one embodiment, a balloon guide catheter is provided that is sized and configured to be advanced through the carotid siphon to perform procedures around the cavernous or clinoid segments of the internal carotid artery of the neurovasculature. In one embodiment, the balloon guide catheter has an outer diameter of approximately 0.09 inches to 0.12 inches and includes an inner assembly having an inner diameter / channel sized to accommodate a catheter smaller than the inner diameter of the inner assembly, the inner diameter being approximately 0.08 inches to 0.09 inches.

[0022] In one embodiment, a manufacturing method for preventing balloon sticking is provided. In one embodiment, the manufacturing method comprises placing one or more longitudinal soldering paths along the outer surface of a balloon catheter tubular element (e.g., a balloon catheter inner assembly). In one embodiment, the manufacturing method comprises placing one or more coils or one or more meshes around the outer surface of the balloon catheter tubular element (e.g., a balloon catheter inner assembly), which in one embodiment then removes the one or more coils or meshes, leaving an imprinted surface. In one embodiment, the manufacturing method comprises creating one or more raised surfaces along the outer surface of the balloon catheter tubular element (e.g., a balloon catheter inner assembly). In one embodiment, the manufacturing method comprises creating one or more recessed, recessed, or concave surfaces along the outer surface of the balloon catheter tubular element (e.g., a balloon catheter inner assembly).

[0023] In one aspect, a method for inhibiting balloon sticking in a balloon catheter is described. In one aspect, the method comprises using a soldering iron to create one or more longitudinal paths along the outer surface of a tubular element of a balloon catheter (e.g., an inner assembly of a balloon catheter). In one aspect, the method comprises placing one or more coils wound around the outer surface of a balloon catheter element (e.g., an inner assembly of a balloon catheter), and in one aspect, the one or more coils are then removed, leaving an imprinted surface. In one aspect, the method comprises placing one or more meshes around the outer surface of a balloon catheter element (e.g., an inner assembly of a balloon catheter), and in one aspect, the one or more meshes are then removed, leaving an imprinted surface. In one aspect, the method comprises creating one or more raised surfaces along the outer surface of a tubular element of a balloon catheter (e.g., an inner assembly of a balloon catheter). In one aspect, the method comprises creating one or more recessed, recessed, or concave surfaces along the outer surface of a tubular element of a balloon catheter (e.g., an inner assembly of a balloon catheter). In one aspect, the method comprises disposing a membrane element circumferentially around a partial outer surface of a tubular element of a balloon catheter (e.g., an inner assembly of a balloon catheter), the membrane element being substantially non-adhesive. In one aspect, a tubular band element is then disposed over a distal portion of the membrane element. In one aspect, one or more raised surfaces are disposed along the exposed surface of the tubular element of the balloon catheter (e.g., an inner assembly of a balloon catheter) to create a sticking or adhesion-preventing surface. In one aspect, one or more recessed, recessed, or concave surfaces are disposed along the exposed portion of the tubular element of the balloon catheter corresponding to gaps in the covering membrane.

[0024] In one aspect, a method of performing a vascular procedure is presented, comprising providing a balloon catheter (e.g., a balloon guide catheter) having a substantially non-adhesive membrane element along a distal portion thereof, delivering the balloon catheter to a target treatment site, and delivering an inflation fluid to the balloon to inflate the balloon, wherein the substantially non-adhesive membrane element promotes proper inflation by preventing the balloon from sticking.

[0025] In one aspect, a method of performing a vascular procedure is described, comprising providing a balloon catheter (e.g., a balloon guide catheter) having one or more raised surfaces along a distal portion of the balloon catheter, delivering the balloon catheter to a target treatment site, and delivering an inflation fluid to the balloon to inflate the balloon, wherein the raised surfaces promote proper inflation by preventing the balloon from sticking.

[0026] In one embodiment, a method of performing a vascular procedure is described. In one embodiment, the method comprises providing a balloon guide catheter and navigating the balloon guide catheter through at least a portion of the carotid siphon, inflating the balloon (e.g., to stop blood flow), and positioning a catheter through the balloon guide catheter at a target treatment location to perform the procedure. In one embodiment, the procedure is aspiration, using suction or vacuum via a catheter delivered through the balloon guide catheter. In one embodiment, the procedure is thrombectomy, using a mechanical clot retrieval device delivered through a catheter delivered through the balloon guide catheter. In one embodiment, the procedure is liquid embolic delivery, using a liquid embolic delivered through a catheter delivered through the balloon catheter. In one embodiment, the procedure is embolic delivery, using one or more embolic devices (e.g., embolic coils) delivered through a catheter delivered through the balloon catheter.

[0027] In one aspect, a method of performing a vascular procedure is presented, comprising providing a balloon guide catheter, navigating the balloon guide catheter through at least a portion of the carotid siphon, inflating the balloon (e.g., to stop blood flow), and using the inner lumen of the balloon guide catheter for aspiration or to deploy a device or substance (e.g., a mechanical clot retrieval device, a liquid embolization, or an embolic device) at a treatment site located proximate the balloon guide catheter.

[0028] In one aspect, a method of performing a vascular procedure is presented, comprising providing a balloon guide catheter, navigating the balloon guide catheter through at least a portion of the corpus cavernosum segment of the internal carotid artery, inflating the balloon (e.g., to stop blood flow), and using the inner lumen of the balloon guide catheter for aspiration or to deploy a device or substance (e.g., a mechanical clot retrieval device, a liquid embolization, or an embolic device) at a treatment site located proximate the balloon guide catheter.

[0029] In one aspect, a method of performing a vascular procedure is described. In one aspect, the method includes providing a balloon guide catheter, tracking the balloon guide catheter through at least a portion of the internal carotid artery, inflating the balloon (e.g., to stop blood flow), and using the inner lumen of the balloon guide catheter for aspiration or to deploy a device or substance (e.g., a mechanical clot retrieval device, a liquid embolization device, or an embolic device) at a treatment site located near the balloon guide catheter. In one aspect, the balloon guide catheter tracks through at least one of the neck segment (C1), petrous segment (C2), foramen ovale segment (C3), corpus cavernosum segment (C4), or clinoid segment (C5) of the internal carotid artery. [Brief explanation of the drawings]

[0030] These and other aspects, features, and advantages enabled by practices of the present invention will be apparent and made clear from the following description of embodiments of the invention, which proceeds with reference to the accompanying drawings.

[0031] [Figure 1] FIG. 1 shows a balloon affixed to a portion of a balloon catheter.

[0032] [Figure 2] FIG. 10 shows a balloon with an incomplete profile due to the balloon being stuck to a portion of the balloon catheter.

[0033] [Figure 3] 1 illustrates a balloon catheter (e.g., a balloon guide catheter) according to one embodiment.

[0034] [Figure 4] FIG. 4 illustrates a cross section of the balloon catheter of FIG. 3, according to one embodiment.

[0035] [Figure 5] FIG. 4 illustrates a distal portion of the balloon catheter of FIG. 3, according to one embodiment.

[0036] [Figure 6a-6b] 1A-1C illustrate a distal portion of a balloon catheter incorporating an anti-sticking mechanism, according to one embodiment.

[0037] [Figure 6c] FIG. 1 illustrates a cross section of a balloon catheter with a protruding surface applied, according to one embodiment.

[0038] [Figure 6d] FIG. 1 illustrates a cross section of a balloon catheter with a recessed surface applied, according to one embodiment.

[0039] [Figure 6e]FIG. 1 illustrates a cross section of a balloon catheter with protruding and recessed surfaces applied, according to one embodiment.

[0040] [Figure 6f] FIG. 1 illustrates a cross section of a balloon catheter with protruding and recessed surfaces applied, according to one embodiment.

[0041] [Figure 6g] FIG. 1 illustrates a cross section of a balloon catheter with multiple protruding surfaces applied, according to one embodiment.

[0042] [Figure 6h] FIG. 1 illustrates a cross section of a balloon catheter with multiple recessed surfaces applied, according to one embodiment.

[0043] [Figure 6i] FIG. 1 illustrates a cross section of a balloon catheter with multiple protruding and multiple recessed surfaces applied, according to one embodiment. [Figure 6j] FIG. 10 shows a cross section of a balloon catheter with multiple protrusions and multiple depressions applied, according to one embodiment.

[0044] [Figure 6k] FIG. 1 illustrates a cross section of a balloon catheter with multiple spot-shaped protruding surfaces and multiple spot-shaped recessed surfaces applied, according to one embodiment.

[0045] [Figure 6l] FIG. 10 shows a cross section of a balloon catheter with the application of coiled elements used to create spiral groove depressions, according to one embodiment.

[0046] [Figure 7] 1A-1C illustrate a distal portion of a balloon catheter incorporating a membrane and purge passage, according to one embodiment.

[0047] [Figure 8]FIG. 10 illustrates a balloon guide catheter used as a conduit for a smaller treatment catheter, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0048] Specific embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments shown in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

[0049] It should be noted that proximal and distal directions may be referenced. Proximal refers to a direction toward the outside of the body, toward the treating physician, and away from the location of the treatment. Distal refers to a direction closer to the vasculature and closer to the intended treatment site. Thus, a medical device (e.g., a balloon catheter) being pushed distally is being advanced closer to the treatment site, and a device being pulled proximally is being pulled away from or across the treatment site.

[0050] As mentioned in the Background section, balloon catheters can have the problem of the balloon potentially sticking to parts of the balloon catheter. Such sticking can occur for a variety of reasons. For example, if the balloon is soft and compliant, which is a common feature of neurovascular balloons or balloons used in smaller or more delicate areas of the vasculature, this softness and compliance can cause such sticking or adhesion to parts of the balloon catheter (e.g., the inner portion that is radially disposed within the balloon).

[0051] Such sticking is primarily a problem when the balloon is in an uninflated state, and a portion of the balloon may stick to a portion of the catheter while in this uninflated state. This area of ​​the balloon will remain adhered to the surface of the catheter during inflation, causing the balloon to be in an incompletely inflated state or shape.

[0052] FIG. 1 illustrates one such severe example, where the balloon 102 is not fully inflated due to adhesion of the balloon 102 to a portion of the balloon catheter's inner element / guidewire port 106, creating a gap 108 that exposes a portion of the inner element 106. The particular type of balloon catheter illustrated is known as a dual-lumen balloon catheter, which uses one outer element that functions as an inflation lumen used to inflate the balloon and one inner element that functions as a guidewire port. One advantage of a dual-lumen system is that a guidewire can be used to advance the balloon catheter to the treatment site using the inner element 106, allowing the balloon catheter to track over the guidewire. Procedures without such a guidewire port require navigating the guidewire to the treatment site, moving a sheath or guide catheter over the guidewire to track over the guidewire, completely withdrawing the guidewire, and then pushing the balloon catheter through the sheath or guide catheter to the treatment site, which is a more tedious and time-consuming process.

[0053] In another example, the balloon may stick to another portion of the balloon catheter, such as the inflation lumen used to inflate the balloon. Such sticking may occur in the dual lumen devices (including the guidewire port) described above, or in single lumen balloon catheters (using only the outer element / inflation lumen). Figure 2 shows an example where sticking of the balloon 102 results in the balloon having an imperfect or asymmetric shape 110.

[0054] Such sticking or adhesion of the balloon to portions of the balloon catheter can cause various complications, as discussed in the Background section. For example, this problem can reduce the effectiveness of the balloon in intravascular procedures by preventing the balloon from assuming a perfect shape (e.g., a perfect circular, elliptical, or oval shape).

[0055] Balloon catheters can be used in a variety of procedures. For example, they can be used to create a hemostasis or proximal barrier to increase suction force in aspiration procedures, to create a proximal barrier in liquid embolic delivery procedures (e.g., to prevent emboli from dissipating outside the treatment area), and as a framework or support member in embolic (e.g., vaso-occlusive coil) delivery procedures. The inability of the balloon to assume a fully inflated shape can reduce the effectiveness of these procedures because the balloon cannot completely seal against the vessel. For example, in thrombectomy or aspiration procedures (thrombectomy uses a mechanical clot retrieval device, and aspiration utilizes suction or vacuum to remove a clot), the inability of the balloon to assume a fully / sufficiently inflated shape to occlude the vessel can result in clot migration or reduced aspiration effectiveness in the aspiration procedure. In vascular occlusion procedures where the balloon serves as a framework, the inability of the balloon to assume a fully inflated shape can cause the vaso-occlusion coil or vaso-occlusion device to detach from the treatment site (e.g., an aneurysm or portion of the occluded blood vessel), reducing the effectiveness of the procedure or causing the device to migrate to another location, creating a risk of blood clots. In liquid emboli delivery procedures, the inability of the balloon to assume a fully inflated shape due to sticking can cause the liquid emboli to backflow away from the treatment site, creating a risk of blood clot formation or stroke at a proximal location, or the blood can push the emboli distally, creating a risk of blood clot formation or stroke at a distal location. Liquid emboli are commonly used, for example, to block blood vessels or occlude arteriovenous malformations (AVMs).

[0056] Balloon catheters and dual lumen balloon catheters, including balloon catheters for neurovascular treatment, are described in U.S. Patent Nos. 9,884,172 and 10,786,659, both of which are incorporated herein by reference in their entireties.

[0057] Physicians may attempt to address the problem of balloon sticking by attempting to over-inflate the balloon by forcing additional inflation media into the balloon to force it into its fully inflated shape. However, such over-inflation can cause the balloon to burst or can dramatically increase the pressure of the balloon against the vessel wall, potentially causing rupture over time and potentially trauma to the vessel.

[0058] The embodiments presented herein address these problems by addressing the issue of balloon sticking or adhesion.

[0059] 3 illustrates a dual lumen balloon catheter 200 according to one embodiment, including an inflatable balloon 202, an outer assembly 204 having a passageway 204a therein that serves as a conduit for inflation fluid to inflate the balloon, and an inner assembly 206 having its own passageway therein. In one example, a liquid inflation medium, such as contrast or saline, is used to inflate the balloon 202, and the inflation medium is delivered through the passageway 204a in the outer assembly 204.

[0060] Each of the inner assembly 206 and the outer assembly 204 is tubular (e.g., a tubular assembly) and is arranged such that the inner assembly 206 is concentrically positioned within the outer assembly 204. Each of the inner assembly 206 and the outer assembly 204 can be considered a tubular assembly (e.g., the inner tubular assembly 206 and the outer tubular assembly 204). The inner assembly 206 and the outer assembly 204 each include a passageway, channel, or elongated lumen 206a and lumen 204a extending along their respective lengths. The outer assembly 204 has a lumen 204a formed therein that is partially occupied by the inner assembly 206, which extends along the entire length of the outer assembly 204 and distally extends past the outer assembly 204, as shown in FIG. 3 .

[0061] The inner assembly 206 and the outer assembly 204 can each be constructed from various combinations of polymer layers and metal reinforcing layers (e.g., metal coils or metal braids). In one example, the outer assembly 204 and the inner assembly 206 each use multiple polymer layers. In one example, the outer assembly 204 and the inner assembly 206 each use multiple polymer layers, and at least one of the outer assembly 204 and the inner assembly 206 can further use at least one metal reinforcing layer for additional structural strength. Different portions of the inner assembly 206 and the outer assembly 204 can be constructed from various combinations of structural layers; for example, more proximal portions can use stronger materials (e.g., harder polymers) while more distal portions can use more flexible materials (e.g., softer polymers).

[0062] A cross section of the balloon catheter showing the inner assembly 206 and outer assembly 204 is shown in more detail in Figure 4. The inner assembly 206 includes a lumen 206a, which in one embodiment serves as a passageway for the dual lumen balloon 200, functioning as a balloon guide catheter. The outer assembly 204 includes an inflation lumen 204a formed in the space between the inner wall of the outer assembly 204 and the outer wall of the inner assembly 204, representing the open space between the inner and outer assemblies 206, 204.

[0063] The proximal end of the balloon catheter 200 is provided with a hemostatic adapter or Y-adapter (not shown) having two ports (each port forming a Y-branch), one port communicating with the inflation lumen 204a for transporting inflation fluid (e.g., saline or contrast agent) distally toward the balloon 202, and the other port communicating with the inner lumen or passageway 206a for transporting an object (e.g., a catheter containing a medical device or a catheter serving as a passageway for suction).

[0064] The distal portion of inner assembly 206 utilizes a mechanism to prevent the balloon from adhering to the outer surface of inner assembly 206. As shown in Figure 3, inner assembly 206 spans the entire length of balloon catheter 200, including the entire length of balloon 202. The distal portion of balloon catheter 200 is shown in more detail in Figure 5, where the approximate location of the mechanism is indicated.

[0065] Balloon 202 is proximally coupled to outer assembly 204 at locations 202c and 202d, either to the outer surface of outer assembly 204 (as shown in FIG. 5) or along the inner wall of outer assembly 204. Balloon 202 is coupled distally to inner assembly 206 at locations 202a and 202b along the outer surface of inner assembly 206. As shown, balloon 202 is attached to inner assembly 206 or outer assembly 204 (e.g., via adhesive) at these coupling locations 202a-202d, and therefore does not expand at these coupling locations. In other words, the portions of balloon 202 between these coupling locations expand or contract, but balloon 202 is fixed and does not expand at coupling locations 202a-202d.

[0066] Region 208 of balloon catheter 200 is shown in more detail in Figures 6a and 6b. Note that viewing from left to right in the figures is from proximal to distal, with the right side considered to be the distal end of the balloon catheter. A membrane 210 overlies the outer surface of inner assembly 206. An elongated purge passage or channel 212 is disposed in a structural layer or wall of inner assembly 206 and is located below membrane 210. Distal to the membrane 210 is a marker band 214 that includes a gap 216 corresponding to channel 212.

[0067] The membrane 210 is disposed around the outer surface of the inner assembly 206. In one embodiment, the membrane 210 is made from a sheet of material that, when the edges of the sheet are curled together, has an overall circumference that is smaller than (or similar to) the circumference of the inner assembly 206. As a result, the edges of the sheet do not bond together when disposed around the circumference of the inner assembly 206. This creates a gap between the two ends of the membrane 210 when the membrane 210 is disposed around the circumference of the inner assembly 206. This gap creates an exposed portion 218 of the inner assembly 206 that is not covered by the membrane 210. In one embodiment, the membrane 210 is disposed around the circumference of the inner assembly 206, and then a portion of the membrane 210 is cut or removed to create the exposed portion 218 of the inner assembly 206. The membrane 210 is bonded to the inner assembly 206, for example, via an adhesive or by a mechanism such as a marker band 214 disposed on a distal portion of the membrane 210.

[0068] Because membrane 210 covers a partial circumferential portion of inner assembly 206, membrane 210 can also be considered, for example, as an overlaid layer (e.g., covering a partial circumferential portion of inner assembly 206), an overlaid element, a partial circumferential layer / element, a radially outer layer / element, or an outer layer / element.

[0069] The outer, or exterior, surface of inner assembly 206 has an exposed portion 218 (meaning not covered by membrane 210), and one or more elements 220 are disposed in exposed portion 218. Elements 220 are configured as irregularities, protruding surfaces, or recessed surfaces that function to create an uneven surface to prevent the balloon from sticking when the balloon is in a deflated state. The created surface prevents the balloon from sticking or adhering to the surface of inner assembly 206 (e.g., along exposed portion 218).

[0070] FIG. 6a is a view (e.g., a top view) of region 208 of balloon catheter 200, showing an elongated purge passageway or channel 212 disposed within inner assembly 206 and beneath membrane 210. FIG. 6b is another view (e.g., a bottom view) of region 208, showing exposed portion 218 and one or more elements 220 along exposed portion 218, which will be described in more detail below. In one example, channel 212 and element 220 are circumferentially opposed at 180 degrees. In another example, they are circumferentially offset by an angle (e.g., between 5 and 180 degrees or between 90 and 180 degrees).

[0071] In one embodiment, element 220 comprises one or more recessed, grooved, or concave regions extending inward from the surface of inner assembly 206. These recesses can be created in a variety of ways, for example, by placing a wire or mandrel on the surface of inner assembly 206 and then heating it along its length (e.g., via a soldering iron or other soldering iron) to imprint the surface of inner assembly 206. The wire or mandrel is then removed, leaving behind the imprinted shape to form the recessed, grooved, or concave surface (e.g., as shown in FIG. 6d). To create multiple recessed surfaces, this approach can use multiple wires arranged around exposed portion 218 of inner assembly 206. In one embodiment, the recessed, grooved, or concave regions are created by a heating element threaded along the surface of inner assembly 206, causing melting inward from the surface of inner assembly 206 and leaving concave surfaces along the path of the heating element. In one embodiment, the process for creating the recessed region involves displacing material from the recessed region to an area adjacent to the recess, leaving a recess and a raised area of ​​displaced material immediately adjacent to the recess.

[0072] In one embodiment, element 220 comprises one or more protruding regions that protrude outwardly from a surface of inner assembly 206 (e.g., as shown in FIG. 6c), which may be formed, for example, by utilizing flux from a soldering iron in an additional volume to create a protruding surface along the path of the soldering iron.

[0073] In one embodiment, the recessed or protruding regions form one or more continuous lines. In one embodiment, the recessed or protruding regions are substantially helical (e.g., extending in a spiral or coiled path along the surface of the inner assembly 206). In one embodiment, the recessed or protruding regions are substantially spot-like or punctate, with the protruding or recessed surface applied at localized points along the surface of the inner assembly 206.

[0074] In some embodiments, various additive techniques such as deposition, 3D printing, and additive elements (e.g., elements glued or physically attached to the outer surface of the inner assembly 206) can be used to create protruding surfaces. In some implementations, techniques such as deposition, 3D printing, and subtractive techniques (e.g., using pin or rigid elements to remove outer portions of the inner assembly 206) can be used to create recessed or concave surfaces along the inner assembly 206.

[0075] 6c shows a cross section where membrane 210 is partially positioned outside around a portion of inner assembly 206, leaving exposed portion 218, and further applying protruding surface 220a along inner assembly 206. Note that more than one protruding surface 220a can be applied along exposed portion 218. Furthermore, protruding surface 220a can be combined with a recessed, concave, or recessed surface (as shown in FIG. 6d), for example, a protruding surface can be positioned adjacent to or adjacent to a recessed, concave, or recessed surface, as shown in FIGS. 6e and 6f.

[0076] 6c-6e are useful in illustrating how the protruding surface 220a or recessed surface 220b contributes to preventing balloon sticking. Without these elements 220a or 220b, the entire exposed portion 218 of the inner assembly 206 would be able to contact a portion of the balloon 220, creating a large area of ​​potential sticking. However, the inclusion of elements 220a or 220b creates an uneven or bumpy surface, reducing the total surface area available for contact with the balloon 200 in its uninflated state, thereby reducing the risk of balloon sticking or adhesion. For example, with the use of the raised surface 220a, the uninflated balloon 200 may only contact the “top” portion of the raised surface 220a, and is less likely to contact adjacent areas as the balloon 200 “lifts” relative to the remainder of the exposed portion 218. With recessed surface 220b, balloon 200 in an uninflated state may only contact a portion of the "elevated" surface adjacent to recessed surface 220b, but not recessed surface 220b itself. In other words, the inclusion of element 220a or element 220b reduces the total surface area accessible to balloon 200 when uninflated, thereby reducing the risk of sticking when balloon 200 is inflated.

[0077] In one example, a plurality of protrusions (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) are formed equidistantly circumferentially around the distal portion of inner assembly 206. In one embodiment, these protrusions are applied only along exposed portion 218 of inner assembly 206. One advantage of such a configuration is that the manufacturing process to create the protrusions only needs to be applied to exposed portion 218 of inner assembly 206 (i.e., the portion of inner assembly 206 not covered by membrane 210) rather than the entire circumference of inner assembly 206, thereby facilitating the manufacturing and assembly process. In another embodiment, these protrusions are applied along the entire circumference of the distal portion of inner assembly 206, where membrane 210 is disposed around the periphery of inner assembly 206 and the grooves are exposed only along exposed portion 218.

[0078] 6d shows a cross section in which membrane 210 is partially positioned outside around a portion of inner assembly 206, leaving exposed portion 218, and further applying a recessed, concave, or recessed surface 220b along inner assembly 206. Surface 220b can also be thought of as a groove. Note that more than one recessed, concave, or recessed surface 220b can be applied along exposed portion 218. Furthermore, recessed, concave, or recessed surface 220b can be combined with a protruding surface (shown in FIG. 6c), for example, a protruding surface can be positioned adjacent to or adjacent to a recessed or recessed surface.

[0079] In one example, a plurality of grooves (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) are formed at equidistant circumferential intervals around the distal portion of inner assembly 206. In one embodiment, the grooves are applied only along exposed portion 218 of inner assembly 206. One advantage of such a configuration is that the manufacturing process to create the grooves only needs to be applied to exposed portion 218 of inner assembly 206 (i.e., the portion of inner assembly 206 not covered by membrane 210) rather than the entire circumference of inner assembly 206, thereby facilitating the manufacturing and assembly process. In another embodiment, the grooves are applied along the entire circumference of the distal portion of inner assembly 206, where membrane 210 is disposed around the periphery of inner assembly 206 and the grooves are exposed only along exposed portion 218.

[0080] In one embodiment, one or more longitudinal grooves / recesses 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 then heated and forced inward from the outer surface of the inner assembly 206 using a soldering iron. The soldering iron is moved along the length of the mandrel or wire to ensure uniform heating and forcing into the inner assembly 206. Once the grooves are formed, the mandrel is removed and repositioned to create another longitudinal groove in another circumferential portion of the inner assembly 206 (if multiple grooves are desired).

[0081] Another embodiment of element 220 may apply one or more spot-like recesses (i.e., concave, recessed, or recessed surfaces) or one or more spot-like protrusions, created, for example, by placing a soldering iron or a piercing element (e.g., a pin) on various portions of the outer surface of inner assembly 206 to form several different surfaces or structures across exposed portion 218 of inner assembly 206.

[0082] It should be noted that the various embodiments presented for creating surface features (e.g., grooves, depressions, ridges, protrusions, indentations, recesses, etc.) on the surface of the catheter are used to create a non-smooth surface to prevent balloon sticking or adhesion. Thus, these elements (e.g., grooves, depressions, ridges, protrusions, indentations, etc.) may be considered surface features, irregular areas, surfaces with varying shapes or contours, or substantially non-smooth surfaces to achieve such purposes. Furthermore, when these elements protrude from the surface of the catheter (e.g., inner assembly 206), they may be considered surface protrusions, surface ridges, etc. When these elements recess from the surface of the catheter (e.g., inner assembly 206), they may be considered surface grooves, surface dimples, surface recesses, surface recesses, etc. As described herein, the surface features reduce or eliminate the risk of balloon sticking or adhesion by reducing the contact area between the inner portion of the balloon 200 and the inner assembly 206 (e.g., the exposed portion 218 of the inner assembly 206).

[0083] In one embodiment, membrane 210 is non-sticky or substantially non-sticky, preventing the balloon from adhering to the membrane in its deflated state. In one example, membrane 210 is constructed of ePTFE. In this manner, balloon 202 is prevented from adhering to the surface of inner assembly 206 by both the non-sticky nature of membrane 210 and anti-adhesion elements 220 along gap portions 218 not covered by membrane 210. One factor affecting balloon adhesion is the relative softness of the materials in contact with balloon 202; therefore, membrane 210 is preferably constructed of a harder material than balloon 202.

[0084] In one embodiment, membrane 210 extends from the distal end of inner assembly 206 by approximately 1-50 mm, 5-30 mm, 5-15 mm, 5-10 mm, or approximately 7-8 mm. In one example, elements 220 (e.g., protrusions 220a, depressions 220b) extend from the distal end of inner assembly 206 by approximately 1-50 mm, 5-30 mm, 5-15 mm, 10-15 mm, or approximately 13 mm. In these embodiments, membrane 210 and elements 220 do not extend the entire length of balloon 202. One reason for this is that balloon sticking is generally more of a problem in the distal region of the balloon. To increase flexibility in the distal region of the catheter, inner assembly 206 (as described below) uses soft polymer elements in the distal end region that create or contribute to potential sticking problems. Additionally, the more inward portions of balloon 202 (e.g., portions further away from bonding locations 202a-202d shown in FIG. 5) do not necessarily rest directly against or adjacent to the surface of inner assembly 206 when the balloon is in a deflated state, meaning that balloon sticking or adhesion is a greater factor along the distal region of balloon 202.

[0085] In another embodiment, membrane 210 and / or elements 220 may be used along substantially the entire length of balloon 202, or along a surface of inner assembly 206 corresponding to a majority of balloon 202. When membrane 210 and / or elements 220 are disposed along substantially the entire length of balloon 202, this corresponds to substantially the entire length of the portion of inner assembly 206 that is disposed distal to outer assembly 204, since balloon 202 is coupled proximally to outer assembly 204 and distally to inner assembly 206, as shown in FIG.

[0086] Membrane 210 contains numerous pores (e.g., numerous small pores that create a porous structure) that serve another important function in that they allow gas to pass through the membrane into the underlying channels 212; in this way, channels 212 can be considered purge or degassing passages. The pores in membrane 210 are large enough to allow gas to pass into the underlying channels, but too small to allow liquid to pass through. In this manner, the membrane allows gas to pass through while retaining liquid, allowing a user to deflate or degas the balloon prior to an intravascular procedure. To prepare the balloon for an intravascular procedure, a user pumps an inflation medium (e.g., saline or contrast agent) into the balloon, allowing the inflation medium to expel any retained gas or air, which is forced out of the membrane through the pores and into channels 212. Once the inflation media begins to inflate the balloon, the user knows that all air or gas has been removed from the balloon, and the user can then pull the syringe plunger proximally or use a vacuum system to pull the inflation media back from the balloon 202, causing it to deflate.

[0087] The channel 212 extends completely to the distal end of the balloon catheter 200 (i.e., opens at the distal end of the inner assembly 206), and thus the channel 212 allows gas or air to escape distally from the balloon catheter 200 / balloon 202. In another example, the channel 212 terminates at a location proximal to the distal end, but the portion of the inner assembly 206 to which the channel 212 is applied is thicker than the distal end portion of the inner assembly 206 lacking the channel (e.g., a small recessed distal end portion is located distal to the portion to which the channel 212 is applied), such that the channel 212 still escapes gas or air from the inner assembly 206.

[0088] In one example, membrane 210 is a layer of ePTFE having a thickness of approximately 0.0006-0.0007 inches and a pore size of approximately 0.4-0.6 μm. Pores in this size range prevent the passage of liquids (e.g., saline or contrast media) while allowing the passage of air / gas. The polymer of the membrane can be treated in a number of different ways to impart pores of the appropriate size to create the membrane. In one preferred embodiment, the polymer is heat-treated to make it stretchable, then stretched to create several pores therein, and then reheated to set the specific stretched shape. In another embodiment, a chemical is used that penetrates and erodes the polymer to create the membrane. In another embodiment, an electrospinning process can be used to create a web-like structure with pores of the appropriate size. In another embodiment, the membrane is a porous foam.

[0089] The membrane 210 (e.g., ePTFE), as described above, is substantially non-sticky and will not adhere to the balloon material. The balloon 202 is preferably formed from a soft material useful for neurovascular applications. In one embodiment, the balloon 202 is formed from a polyblend 45A or other polymeric elastomeric material. The balloon 202 may have an outer diameter of up to about 15 mm and a length ranging from 5 to 50 mm, preferably from 10 to 20 mm.

[0090] Two flexible surfaces tend to stick or adhere to each other. The balloon catheter 200 includes a softer distal end portion of the inner assembly 206, made of a soft polymer material (e.g., low-density polyethylene or low-durometer Pebax), which is positioned around the outer periphery of the inner assembly 206 and underneath the membrane 210. The softer distal surface contributes to increased flexibility along the distal portion of the balloon catheter 200. The membrane 210 (e.g., made of ePTFE) is at least slightly harder than the underlying soft polymer material of the inner assembly 206, thereby reducing sticking between the membrane 210 and the balloon 202 due to the increased relative hardness of the membrane 210. Furthermore, the pores in the membrane 210 create numerous small irregularities across the surface of the membrane 210, creating an uneven surface that further helps prevent the membrane 210 from sticking.

[0091] An additional advantage of using a softer distal tip portion for the inner assembly 206 (e.g., with a low density polyethylene or low durometer Pebax distal element) is that since the distal end of the inner assembly becomes the distal end or terminus of the balloon catheter 200, the softer the tip, the less damage the balloon catheter 200 can potentially cause to the blood vessel. In this manner, a softer distal end is less traumatic to the blood vessel.

[0092] FIG. 7 is another view of the distal portion of the balloon catheter 200, illustrating the membrane 210 and purge passage 212 in more detail, with the distal portion of the balloon catheter 200 shown on the right. The inner assembly 206 is comprised of a polymeric inner liner 226 (e.g., PTFE) and an overlying structural polymer layer 228. The membrane 210 is disposed on top of the polymer layer 228, with the outer surface of the membrane 210 facing the inner surface of the balloon 202. Thus, when the balloon 202 is uninflated, it rests against the membrane 210, and when the balloon 202 is inflated, it assumes the configuration shown in FIG. 7. The distal portion of the balloon 202 is bonded to the distal portion of the membrane 210 as shown in FIG. 7, and as previously described, the balloon is proximally and distally bonded (e.g., proximally bonded to the distal portion of the outer assembly 204 and distally bonded to the distal portion of the inner assembly 206).

[0093] The elongated purge passages or channels 212 are formed during the assembly process by placing a thin mandrel rod within the polymer layer 228. After assembly, the mandrel rod is removed, leaving the elongated passages 212 shown in FIG. 7. The membrane 210 is placed over the polymer layer 228 (including the elongated passages 212). The membrane 210, as previously described, wraps around a portion of the outer periphery of the polymer layer 228 of the inner assembly 206, leaving a circumferential gap corresponding to the exposed portion 218 of the inner assembly 206, as shown in FIGS. 6b-6d.

[0094] In one embodiment, the polymer layer 228 is a relatively soft material (e.g., low density polyethylene or low durometer Pebax), whereby the addition of a harder membrane 210 (e.g., a higher durometer polymer or a denser ePTFE molecular profile is used for the membrane 210) on top of the polymer layer 228 can be useful in reducing any sticking between the highly compliant / soft balloon 202 and the inner assembly 206.

[0095] In one embodiment, the polymer layer 228 is a harder / stiffer polymer (e.g., high density polyethylene or high durometer Pebax), and then an additional layer of softer material (e.g., low density polyethylene or low durometer Pebax) is placed over this polymer layer 228 along the distal portion of the inner assembly 206 (e.g., along the portion of the inner assembly 206 that underlies the membrane 210) to increase flexibility along the distal region of the inner assembly 206 to improve the trackability of the balloon catheter 200.

[0096] 7 also shows purge ports 224, which act as conduits between the balloon and purge passages or channels 212. Purge ports 224 act as conduits for gas to escape from the balloon as it flows through the pores in membrane 210 and into purge passages 212.

[0097] Previously illustrated embodiments (e.g., shown in FIG. 6b ) specifically address the application of elements 220 within exposed portions of the inner assembly 206 not covered by the membrane 210 to provide a mechanism for preventing balloon sticking or adhesion in those portions not covered by the membrane 210. Elements 220 can have a variety of configurations, including raised or protruding surfaces, recessed / grooved / concave / recessed surfaces, etc., as previously described. In alternative embodiments of these elements 220, various configurations can be used to create uneven, non-smooth, or non-uniform shapes to prevent balloon sticking to the surface. In one embodiment, a coil (e.g., coiled metal) is placed on the outer surface of the inner assembly 206 and later removed, imprinting the coil shape onto the outer surface. The coil leaves a linear array of circular imprints, i.e., helical grooves, where the coil was located. This creates a bumpy, imprinted, or recessed shape in the area where the coil was previously located, and a raised or protruding surface (more raised than the area where the coil was located) in adjacent areas. In another embodiment, braiding can be used to create more complex imprinted surface shapes. With an overlying membrane 210 (only a portion 218 of the inner assembly 206 is exposed), element 220 is positioned along the entire exposed portion 218 of the inner assembly 206 and also underneath membrane 210, but element 220 is only exposed, thus providing the functional effect of inhibiting sticking or adhesion along exposed portion 218.

[0098] In one embodiment, a wire is wrapped around the outer surface of inner assembly 206 and then heated. A tube of heat shrink tubing is then placed around the wire and heat is applied, causing the tube to shrink onto the wire, forcing the heated wire against the outer surface of the inner tubular element and forming the grooves. Upon cooling, the shrunk tube is removed from inner assembly 206, and the wire is then removed, leaving the grooves. Next, membrane 210 is placed over a portion of inner assembly 206, leaving an exposed grooved surface located in exposed gap portion 218.

[0099] In one embodiment, a braided braided tube may be used in a similar manner to form different patterns. The distal end of the inner assembly 206 is placed within the braided tube, which is stretched to reduce its diameter around the inner assembly 206, and then the braided tube is heated to a temperature that softens the catheter material. Another heat shrink tube can then be applied to press the braided tube into the catheter, forming patterned impressions on the outer surface of the inner assembly 206. Then, as described above, the membrane 210 is placed around a portion of the inner assembly 206.

[0100] In another embodiment, membrane 210 may be used that is positioned around the entire distal portion of inner assembly 206 (e.g., so that there are no exposed portions 218 of inner assembly 206). The non-stick properties of membrane 210 to the inner surface of balloon 202 will prevent the balloon from sticking.

[0101] Another embodiment can avoid the use of membrane 210 entirely. Instead, longitudinal grooves / dimples, longitudinal protrusions, spotted recesses, spotted protrusions, spiral grooves, spiral protrusions, etc., as described in the previously illustrated embodiments, are circumferentially disposed along the outer portion of inner assembly 206. One advantage of a system that uses one or more longitudinal grooves or dimples circumferentially disposed along inner assembly 206 without using a membrane is that, if these grooves or dimples span a significant length of balloon 202, they can be used to transport inflation fluid (e.g., contrast agent or medication) distally to balloon 202, which can be useful for achieving a more uniform or consistent inflation process. The grooves or dimples (e.g., 220b) provide a grooved surface that allows the inflation fluid to pass through, and as more inflation fluid is applied to the balloon, the inflation fluid is pushed distally, thereby ensuring a more uniform inflation shape, particularly along the distal portion of the balloon. In one example, during preparation to remove air from the balloon, inflation medium is first transferred through the balloon to force air out of the balloon and into the purge passage 212 (described above and shown in FIG. 6a), and the depression will force air distally into the membrane of the balloon catheter 200 and into the purge passage 212, creating a passage for the air to escape from the balloon.

[0102] These concepts are illustrated in Figures 6g-6i, where a membrane is not used and various combinations of protrusions 220a and depressions 220b are used. While straight shapes are shown, in some embodiments (including those using membrane 210), the shapes can be substantially rounded or even pointed. A more pointed shape 220a, 220b is shown in Figure 6j. Figure 6k shows multiple spot-like protrusions 220a and spot-like depressions / indentations 220b randomly distributed across the surface of the inner assembly 206. Figure 6l shows the same configuration in which a coil 236 is first placed on the outer surface of the inner assembly 206, and then the coil 236 is removed, leaving a spiral groove / indentation along the surface of the inner assembly 206 that mirrors the placement of the coil 236.

[0103] It should be noted that even when membrane 210 is used (in which case protrusion 220a or depression 220b has a functional effect along exposed portion 218 of inner assembly 206), depression 220b is still effective in providing a passage for the passage of air during the air evacuation procedure and for the passage of inflation fluid distally along exposed portion 218 of inner assembly 206, thereby providing such procedural benefits.

[0104] The previous embodiments have described various mechanisms for inhibiting balloon sticking in balloon catheters. In some embodiments, these mechanisms are used as part of a balloon guide catheter.

[0105] The Background section discussed various challenges in constructing balloon guide catheters as well as the advantages of such systems. Typically, balloon catheters are delivered through an external guide catheter. When used for neurovascular procedures or procedures in or near the carotid artery, the guide catheter ideally must be able to navigate the carotid siphon, a highly tortuous U- or S-shaped bend in the more distal portion of the carotid artery, particularly the internal carotid artery.

[0106] The carotid siphon provides access to the neurovasculature. If a guide catheter is not flexible enough to navigate through the carotid siphon, it may be unable to navigate this bend, leaving a smaller procedural catheter (e.g., a microcatheter, distal access catheter, or procedural balloon catheter) unprotected when attempting to navigate to the target treatment location.

[0107] Guide catheters are important because they are larger and more rigid, providing support for smaller treatment catheters, but they must be flexible enough to navigate through tortuous anatomical structures such as the carotid siphon. Also, while the guide catheter is flexible enough to navigate the carotid siphon, it must be strong enough not to buckle under the tortuosity and pulsation of the vasculature, and strong enough to act as a support for the small catheters fed through it.

[0108] The use of a balloon guide catheter is particularly advantageous because the guide catheter with its balloon can be used as a support structure and access passageway for a smaller treatment catheter (e.g., a microcatheter, distal access catheter, or smaller treatment balloon catheter fed through the balloon guide catheter to deliver a medical device or therapeutic substance or as a conduit for suction / aspiration). The balloon guide catheter can then be used to perform blood flow stasis proximal to the treatment site, and after placing the smaller treatment catheter through the lumen of the balloon catheter, the balloon can be used to perform, for example, proximal blood flow stasis to restrict blood flow to the treatment area.

[0109] Balloon guide catheters can also be particularly advantageous for certain procedures. For example, in aspiration or thrombectomy procedures used to retrieve a blood clot / thrombus, 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 / thrombectomy procedure is performed. The inner passage of the balloon guide catheter can be used as a conduit for a smaller catheter (e.g., a microcatheter or distal access catheter) to provide a suction conduit or a passage for a thrombectomy device to perform the procedure.

[0110] 8 illustrates an example in which a balloon guide catheter 300 is used to deliver a mechanical thrombectomy device. As will be appreciated by those skilled in the art, the attributes of the above-described embodiments may be applied to other systems, including, for example, balloon guide catheters as disclosed herein.

[0111] The passageway 306a of the inner assembly 306 is used as a passageway for a smaller treatment catheter 330 (e.g., a microcatheter in the example of FIG. 8 ), which houses a thrombectomy device 334. In one example, the thrombectomy device 334 is a stent-like device, also known as a stentreaver, configured like a stent but used to capture blood clots, with an open distal end sized to capture the 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., push the thrombectomy device 334 out of the microcatheter 330). The balloon 302 can be inflated during the delivery procedure (as shown in FIG. 8 ) or can be inflated after the treatment catheter 330 (e.g., a microcatheter) and thrombectomy device 334 have been delivered to the treatment site to perform the clot / thrombectomy procedure. In one example, the thrombectomy device includes multiple engagement members that are used to engage the clot or thrombus, such as the device described in U.S. Pat. No. 9,211,132, which is incorporated herein by reference in its entirety.

[0112] In one exemplary embodiment, treatment catheter 330 serves as a conduit for aspiration, such that a suction / vacuum source (e.g., a vacuum pump) is coupled proximally to treatment catheter 330 to aspirate clots / thrombi at the treatment location. Balloon guide catheter 300 is navigated through (and, if necessary, past) at least a portion of the carotid siphon to access a region of the neurovasculature. Treatment catheter 330 (e.g., a microcatheter, distal access catheter, or smaller balloon catheter) is then navigated through inner passage 306a of balloon guide catheter 300 to the target treatment location. Balloon 302 of balloon guide catheter 300 is inflated to create proximal blood flow stasis and restrict blood flow to the target treatment site, and treatment catheter 330 is then used to perform an aspiration procedure, thereby aspirating or aspirating clots or thrombi into treatment catheter 330.

[0113] The above examples are used for illustrative purposes, as a variety of devices, such as vaso-occlusive coils, liquid emboli, embolic or drug-containing beads / microspheres, embolic mesh stents, etc., can be delivered through treatment catheter 330. In one embodiment, treatment catheter 330 is a smaller balloon catheter, where balloon guide 330 can create proximal flow stasis near the carotid siphon, and this smaller balloon catheter delivered through balloon guide catheter 300 creates flow stasis closer to the treatment location.

[0114] Some of the preceding examples have described the use of proximal blood flow arrest via the balloon 302 of the balloon guide catheter 300. This is useful for several reasons. Inflation of 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. When the balloon guide catheter 300 is positioned proximal to the treatment location (e.g., near the carotid artery, i.e., at or around the carotid siphon), the treatment catheter 330 at the treatment location helps restrict blood flow to the targeted treatment location when the balloon 302 of the balloon guide catheter 300 is inflated. Such blood flow restriction is useful, for example, to prevent clot / thrombus migration further downstream during a retrieval procedure (e.g., when a clot or thrombus may fragment during aspiration or retrieval by a mechanical thrombectomy device). In this manner, blood flow arrest is useful in preventing clots or thrombus from migrating or being dislodged further downstream during a retrieval procedure.

[0115] The cessation of blood flow by 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, with the inner assembly 306 acting as a conduit for aspiration / vacuum, with aspiration being applied through the inner assembly passageway 306a. Such a procedure could be used, for example, when a clot or thrombus is located proximal or slightly distal to the carotid siphon (e.g., where the balloon guide catheter 300 can be easily tracked) rather than in more distal and smaller neurovascular regions. In this way, the balloon 302 provides a proximal blood flow barrier for aspiration procedures when the aspiration procedure is performed using the balloon guide catheter 300 itself.

[0116] In other procedures where treatment catheter 330 is delivered through balloon guide catheter 300 for another purpose (e.g., delivery of vaso-occlusive coils or mesh, delivery of liquid emboli, delivery of embolic / drug-containing beads, etc.), balloon 302 provides proximal blood flow stasis near the treatment site and helps prevent the blood from expelling the therapeutic substance delivered through treatment catheter 330 during the delivery procedure. In this manner, during the procedure, balloon 302 is inflated as needed during the procedure, and after the therapeutic substance has been delivered through treatment catheter 330, treatment catheter 330 is retracted into balloon guide catheter 330, balloon 302 of balloon guide catheter 300 is deflated, and balloon guide catheter 300 is withdrawn from its position.

[0117] The necessary characteristics of a properly functioning balloon guide catheter have been previously described, including sufficient flexibility to navigate the more tortuous anatomical structures of the vasculature (e.g., the carotid siphon) while also having sufficient strength to act as a passageway for smaller catheters (e.g., microcatheters and distal access catheters) that are delivered through the balloon guide catheter.

[0118] The additional features required for a balloon catheter (e.g., inflation lumen, balloon) present unique construction challenges in that the stiffness of a balloon guide catheter can be significantly increased compared to a typical guide catheter, and the inclusion of the balloon and the materials required to inflate the balloon can make the balloon guide catheter significantly stiffer than conventional guide catheters. Certain features can be used to reduce the stiffness and increase the flexibility of a balloon guide catheter. For example, as described in the previously illustrated embodiments, the balloon catheter can be provided with a softer distal polymer portion, such as low-density polyethylene or low-durometer Pebax. However, providing softer features can result in balloon sticking (e.g., due to the softness of the balloon 302 itself). Therefore, using features described in the above-described embodiments (e.g., some configurations are shown in FIGS. 6a-6c) to mitigate the problem of balloon sticking (e.g., through the use of membrane 210 or elements 220 disposed along the surface of inner assembly 206) can be useful in constructing a usable balloon guide catheter.

[0119] In one embodiment, the balloon guide catheter 300 has an inner assembly sized to accommodate a catheter having an outer diameter of approximately 0.09 to 0.12 inches, an inner diameter (referring to the size of the passageway 306a of the inner assembly 306) of approximately 0.08 to 0.09 inches, and a diameter smaller than the inner diameter of the inner assembly. It should be noted that the sizes shown are useful for the particular vasculature region of interest (e.g., when navigating the carotid siphon region of the vasculature), but the balloon guide catheter can be sized larger or smaller as needed.

[0120] The passageway 306a of the inner assembly 306 of the balloon guide catheter 300 has a particular function when used as a conduit for a treatment catheter 330 (e.g., a smaller catheter such as a microcatheter or distal access catheter) that can be used to deliver subsequent items (e.g., medical devices, suction, therapeutic substances, etc.). In one example, the treatment catheter 330 is a distal access catheter, which is then used as a conduit for an even smaller catheter (e.g., a microcatheter) used for delivery of subsequent items (e.g., medical devices, suction, therapeutic substances, etc.). In one example, the distal access catheter itself is used for delivery of subsequent items (e.g., medical devices, suction, therapeutic substances, etc.).

[0121] In one example, the passageway 306a of the inner assembly 306 of the balloon guide catheter 300 is first used as a conduit for a guidewire, which is a small access wire used to navigate the guide catheter to the vicinity of the treatment location (e.g., the carotid siphon region). In one example, the balloon guide catheter is anchored at or distally beyond the carotid siphon, the guidewire is navigated through this region to the treatment location, and the treatment catheter 330 is navigated over the guidewire to the treatment location. The guidewire is then removed.

[0122] In various embodiments, a method of use or treatment is provided. In one embodiment, the method includes a user navigating a balloon guide catheter through at least a portion of the carotid siphon region of the vasculature; positioning a treatment catheter (e.g., a microcatheter or distal access catheter) at a treatment site through the inner assembly or inner passageway of the balloon guide catheter and the distal portion of the balloon guide catheter; inflating the balloon of the balloon guide catheter to cause blood flow stasis proximal to the intended treatment site; and performing the treatment using the treatment catheter. In various embodiments, the treatment can be aspiration, mechanical thrombectomy, or embolic delivery, and the treatment catheter is a conduit for aspiration, a mechanical thrombectomy device, or an embolic material. The mechanical thrombectomy device can be a clot retrieval device or a stentreaver. The embolic material can consist of a liquid embolus, an embolic mesh, or an embolic / vaso-occlusive coil. In one embodiment, the method further comprises the steps of: moving a guidewire through an internal passageway of the balloon guide catheter; using the guidewire to guide the balloon guide catheter to a particular location; and then using the guidewire to guide a treatment catheter to a treatment location (e.g., where the treatment location is distal to the location of the balloon guide catheter). Once the guidewire reaches the intended treatment location, it is retracted.

[0123] In one embodiment, the method comprises navigating or following a balloon guide catheter through at least a portion of the carotid siphon region of the vasculature, inflating a balloon of the balloon guide catheter, and performing a vascular procedure using the internal passage of the balloon guide catheter. In one embodiment, the vascular procedure is aspiration of a blood clot or thrombus, wherein suction, suction, or vacuum is provided through the internal passage of the balloon guide catheter.

[0124] As mentioned above, balloon guide catheters are particularly useful for navigating tortuous or curved sections of the internal carotid artery, such as the carotid siphon. The carotid siphon is a tortuous or curved section that must be navigated to access the neurovasculature because it connects to the neurovascular arteries. The internal carotid artery is composed of several segments. From proximal (away from the neurovasculature) to distal (toward the neurovasculature), these segments include the cervical segment (C1), petrous segment (C2), foramen ovale segment (C3), corpus cavernosum segment (C4), clinoid process segment (C5), ophthalmic artery segment (C6), and C7 (communicating segment). The carotid siphon is located along the distal portion of the corpus cavernosum segment (C4), and the clinoid process segment (C5) is located distal to the carotid siphon.

[0125] When we speak of a balloon guide catheter capable of navigating the carotid siphon, this means that it can be navigated through the corpus cavernosum segment up to the carotid siphon region, and thus has the ability to navigate at least the cavernous segment of the internal carotid artery, i.e., the C4 segment. Depending on the size of the vessel and the flexibility associated with the balloon guide catheter (e.g., embodiments describing various methods for increasing flexibility), a user may be able to navigate the balloon guide catheter to more distal regions, including, for example, the clinoid process C5 segment, or possibly even the ophthalmic artery C6 segment and communicating segment C7. In other words, the balloon guide catheter may be used in more distal regions of the vasculature in some cases. Similarly, the embodiments described herein may be scaled up or down as needed to provide balloon guide catheters or balloon catheters operable in larger or smaller arteries.

[0126] In some instances, the balloon guide catheter 300 can be used for procedures within other segments of the internal carotid artery, such as the C1-C4 segments.

[0127] As previously described herein, methods of use can be understood to refer to the placement of a balloon guide catheter through various portions of the vascular system, such as the internal carotid artery, as well as through relevant portions of the internal carotid artery. Thus, when a user places a balloon guide catheter or balloon catheter through at least a portion of the carotid siphon, this entails advancing the catheter through the C1-C3 segments and at least a substantial portion of the C4 segment, since the carotid siphon is located along the cavernous C4 segment.

[0128] In one embodiment, a method for performing a vascular procedure comprises advancing a balloon guide catheter through the internal carotid artery, through a corpus cavernosum segment of the internal carotid artery, and through at least a portion of the carotid siphon; inflating the balloon; and performing the vascular procedure using the internal passage of the balloon guide catheter. In one embodiment, the method further comprises advancing a procedure catheter through the internal passage of the balloon guide catheter and performing a procedure (e.g., device delivery or aspiration) using the procedure catheter. In one embodiment, the procedure comprises using the internal passage of the balloon guide catheter to perform aspiration near the balloon guide catheter. In one embodiment, the steps described herein can be used with a balloon catheter. In one embodiment, the balloon guide catheter or balloon catheter uses an element (e.g., membrane 210 and / or element 220) to inhibit balloon sticking. In one embodiment, the method described herein is used to perform a procedure along another segment of the internal carotid artery (e.g., the C1, C2, or C3, C5, C6, or C7 segments). If the procedure is performed distally beyond the C4 segment of the corpus cavernosum (e.g., in the C5-C7 segments), the procedure comprises advancing the catheter completely through the carotid siphon. In some embodiments, the methods described herein allow for the advancement of a balloon guide catheter or balloon catheter through any tortuous portion of the vasculature, and the catheter can be sized and targeted (e.g., provided with a sufficient level of strength and flexibility) accordingly.

[0129] It should be noted that, given that the carotid siphon opens into the neurovasculature, it is particularly useful to have a balloon guide catheter advanced through the carotid siphon and be able to effect blood flow cessation (via an inflated balloon) while the balloon guide catheter passageway is used as a conduit for a treatment catheter (e.g., a microcatheter or distal access catheter) used to perform the procedure. In one example, the treatment catheter (e.g., a distal access catheter) is used to perform aspiration in a more distal region (meaning distal to the location of the balloon guide catheter) within the neurovasculature, with the inflated balloon of the balloon guide catheter assisting in the performance of the procedure by helping to reduce blood flow to the target region. In one example, the balloon guide catheter passageway itself is used to perform an aspiration procedure in the vicinity of the balloon guide catheter. This latter example is useful, for example, when a blood clot or thrombus is located in an area where a balloon guide catheter can be advanced (e.g., the C1-C5, C3-C5, or C4-C5 segments of the internal carotid artery).

[0130] It should be noted that while the focus herein has been primarily on methods for inhibiting sticking and using these concepts to create useful balloon guide catheters, these concepts can also be applied to other balloon catheters (e.g., not just balloon guide catheters) to create more useful balloon catheters. Thus, the balloon catheters discussed can incorporate the ideas presented herein for use in a variety of settings and can be sized larger or smaller as needed.

[0131] While the present invention has been described with respect to particular embodiments and applications, those skilled in the art will be able to generate further embodiments and modifications in light of the present teachings without departing from the spirit or scope of the claimed invention. Accordingly, it should be understood that the drawings and descriptions herein are provided by way of example to facilitate understanding of the invention and should not be construed as limiting the scope of the invention.

Claims

1. an outer assembly having an inflation lumen; an inner assembly extending lengthwise of the outer assembly and extending distally beyond the outer assembly; a balloon connected proximally to the outer assembly and distally to the inner assembly, the balloon communicating with the inflation lumen of the outer assembly; a layer covering a partial circumferential portion of the inner assembly; an exposed portion of the inner assembly not covered by the layer; and one or more surface protrusions or one or more surface depressions on the exposed portion of the inner assembly; Balloon catheter.

2. The balloon catheter of claim 1 , wherein the one or more surface protrusions or the one or more surface depressions extend longitudinally along the exposed portion of the inner assembly.

3. The balloon catheter of claim 2 , wherein the one or more surface protrusions or the one or more surface depressions extend longitudinally beyond the exposed portion of the inner assembly.

4. 2. The balloon catheter of claim 1, wherein the one or more surface protrusions or the one or more surface depressions comprise one or more grooves, the one or more grooves being longitudinally disposed around the circumference of the inner assembly.

5. The balloon catheter of claim 1 , wherein the one or more surface protrusions or the one or more surface depressions extend circumferentially along the exposed portion of the inner assembly.

6. The balloon catheter of claim 1 , wherein the one or more surface protrusions or the one or more surface depressions comprise one or more ridges disposed along an outer portion of the inner assembly.

7. 7. The balloon catheter of claim 6, wherein the exposed portion of the inner assembly includes both the one or more surface protrusions and the one or more surface depressions, and the one or more surface protrusions are adjacent to the one or more surface depressions.

8. The balloon catheter of claim 1 , wherein the layer is a substantially non-adhesive membrane.

9. The balloon catheter of claim 1 , wherein the one or more surface protrusions or the one or more surface depressions comprise one or more indentations disposed along an outer portion of the inner assembly.

10. The balloon catheter of claim 1 , wherein the layer comprises a plurality of pores sized to allow the passage of gases while preventing the passage of liquids.

11. 2. The balloon catheter of claim 1, wherein the layer is disposed radially outward of an elongated purge passage located within the inner assembly and configured to release gas from the balloon.

12. The balloon catheter of claim 1 , wherein the balloon is proximally bonded to an outer surface of the outer assembly or along an inner wall of the outer assembly.

13. The balloon catheter of claim 1 , wherein the balloon is distally bonded to an outer surface of the inner assembly.

14. 2. The balloon catheter of claim 1, wherein the balloon is coupled proximally to the outer assembly at first and second positions and distally to the inner assembly at third and fourth positions, and the balloon is not inflated in the first, second, third, and fourth positions.

15. The balloon catheter of claim 1 , wherein the one or more surface depressions are formed from a coil or mesh imprinted on a surface of the inner assembly.

16. The balloon catheter of claim 1 , wherein the layer is secured to the inner assembly.

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