Adhesive-free bonded balloon for balloon guide catheter with minimal profile - Patent Application 20070122997

Abstract

To provide a balloon guide catheter.SOLUTION: A balloon guide catheter comprises: a catheter shaft 125 having an outer layer made of a reflowable material; and a balloon having a bond interface area 110, 115 with a plurality of punctures 120 defined therein, the balloon being secured about the outer layer of the catheter shaft via seepage of the reflowable material of the outer layer into the plurality of punctures forming a radially outward reflow bond between the catheter shaft and the balloon without the use of an adhesive. One or more reflow jackets made of a reflowable material may also be disposed about the bond interface area of the balloon seeping into the plurality of punctures forming a radially inward reflow bond.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] Intravascular catheters with flexible inflatable balloons can be used to stop blood flow during capture and retrieval of intravascular thrombi, obstructions, or clots. The balloon and outer surface of the catheter shaft of the balloon guide catheter of the present invention are secured together with an adhesive-free bond interface, thereby minimizing profile / diameter while optimizing bond strength. [Background technology]

[0002] Acute ischemic stroke is primarily caused by a thrombotic or embolic obstruction (e.g., blockage) in an artery of the brain. The obstruction is typically caused by a blood clot that has broken away from another part of the body and travels antegrade (in the direction of normal blood flow) through the blood vessels, eventually lodges in a neurovascular artery, where it blocks blood flow to a particular area of ​​the brain.

[0003] A procedure known as thrombectomy can be used to remove thrombi, obstructions, blockages, or clots lodged within a blood vessel using a mechanical retrieval device. In a thrombectomy procedure or treatment, a physician or interventionalist introduces a guidewire and microcatheter together into the blood vessel through the vasculature in an artery typically located in the groin or arm, or by direct access through the carotid artery. The guidewire and microcatheter are advanced together to a location proximal to the targeted clot, blockage, or occlusion. The guidewire is then advanced across the clot, followed by the microcatheter. While in a compressed state, a mechanical thrombectomy device can be guided through the lumen of the microcatheter to the target site. After exiting the microcatheter, the mechanical thrombectomy device typically self-expands to its original, expanded state. Mechanical thrombectomy devices are typically made of self-expanding biocompatible materials, such as nickel-titanium. Suction through the catheter may be used in conjunction with or in place of the mechanical retrieval device to remove the clot.

[0004] During thrombectomy procedures, balloon guide catheters are often used to stop blood flow by introducing inflation fluid into a flexible, inflatable balloon. During the manufacture of balloon guide catheters, bonding of the flexible, inflatable balloon to the outer surface of the catheter shaft has two competing criteria: maximizing bond strength and integrity, while simultaneously minimizing the profile / diameter at the bond interface where the balloon attaches to the catheter shaft. Summary of the Invention [Problem to be solved by the invention]

[0005] It would be desirable to design an improved balloon guide catheter with an adhesive-free bond interface where the balloon (e.g., flexible, semi-compliant, or non-compliant) is secured to the outer surface of the catheter shaft to achieve optimal bond strength and integrity while minimizing the profile or outer diameter. [Means for solving the problem]

[0006] One aspect of the present invention is directed to an improved balloon guide catheter in which the balloon is bonded without the use of adhesives, resulting in maximized bond strength and integrity, while minimizing the profile or outer diameter.

[0007] Another aspect of the present invention is directed to a balloon guide catheter comprising: a catheter shaft having an outer layer made of a reflowable material; and a balloon having a bonded interface region with a plurality of punctures defined therein, the balloon being secured around the outer layer of the catheter shaft via penetration of the reflowable material of the outer layer into the plurality of punctures to form a radially outer reflow bond between the catheter shaft and the balloon, the balloon being secureable to the catheter shaft without the use of adhesive.

[0008] Yet another aspect of the present invention is directed to a method for assembling a balloon guide catheter. A plurality of punctures are drilled in a bonding interface region of a balloon that is securable to an outer layer of a catheter shaft made of a reflowable material. The balloon, with the plurality of punctures drilled therein, is disposed around the outer layer of the catheter shaft. Along the bonding interface region, the reflowable material of the outer layer of the catheter shaft is exposed to heat to penetrate into the plurality of punctures and form a radially outward reflow bond between the outer layer of the catheter shaft and the balloon. Thus, the balloon can be secured to the catheter shaft without the use of adhesives. [Brief explanation of the drawings]

[0009] These and other features of the present invention will become more readily apparent from the following detailed description and drawings which illustrate the invention, and in which like reference numerals refer to like elements throughout the several views. [Figure 1] FIG. 1 is a side view of an exemplary flexible inflatable balloon according to the present invention prior to assembly around a catheter shaft, the flexible inflatable balloon having a proximal bonded interface region and an opposing distal bonded interface region, each bonded interface region having a plurality of puncture holes defined therethrough. [Figure 2A] FIG. 2 is a partial side view of an assembled balloon guide catheter including the compliant inflatable balloon of FIG. 1 and a catheter shaft having an outer layer of reflow material that reflows into a plurality of puncture holes defined in the compliant inflatable balloon to form a radially outer reflow bond, the compliant inflatable balloon being shown in an uninflated state. [Figure 2B] 2B is a longitudinal cross-sectional view of the assembled balloon guide catheter of FIG. 2A showing a radially outward reflow bond formed by penetration of the outer layer of reflow material into a plurality of puncture holes defined in the flexible inflatable balloon. [Figure 3] FIG. 2B is a radial cross-sectional view of the outer layer of the catheter shaft of FIG. 2A. [Figure 4A]FIG. 10 is a partial longitudinal cross-sectional view of an alternative configuration in which two reflow jackets / sleeves are axially separated from one another to form a 360° radial gap between them, each reflow jacket / sleeve secured to the outer layer of the catheter shaft below respective proximal and distal bond interface regions of the compliant inflatable balloon, the compliant inflatable balloons being shown in an uninflated state. [Figure 4B] FIG. 4B is a side view of the assembled catheter of FIG. 4A. [Figure 5A] FIG. 10 is a partial longitudinal cross-sectional view of yet another design with a single reflow jacket / sleeve having cutouts or openings defined therein aligned with a flexible inflatable balloon patch secured to the catheter shaft below, the flexible inflatable balloon shown in an uninflated state. [Figure 5B] FIG. 5B is a top view of the assembled catheter of FIG. 5A. DETAILED DESCRIPTION OF THE INVENTION

[0010] The terms "distal" or "proximal" are used in the following description with reference to a location or direction relative to the treating or interventional physician. "Distal" or "distally" is a location or direction away from the physician or interventional physician. "Proximal" or "proximally" or "adjacent" is a location or direction closer to the physician or interventional physician. The terms "occlusion," "clot," or "blockage" are used interchangeably.

[0011] The balloon is typically bonded to the outer surface of the catheter shaft of an assembled balloon guide catheter via an adhesive. The use of adhesive to secure the balloon has several drawbacks, including an increased adhesive profile and difficulty in controlling / constraining the boundary where the adhesive remains. Therefore, one aspect of the present invention is to eliminate the use of adhesive (adhesive-free bonding or non-adhesive bonding) where the flexible inflatable balloon is secured to the outer layer of the catheter shaft without sacrificing bond integrity or strength.

[0012] During thrombectomy procedures, balloon guide catheters are often used to stop blood flow by introducing an inflation fluid into a compliant, inflatable balloon made from an elastomeric material, such as polyurethane, polyblend, or latex, rather than by pressure inflation. Due to their ability to conform to the shape of vascular structures, compliant, inflatable balloons are particularly well-suited for use in stopping blood flow. For other applications, such as dilating blood vessels or opening blockages, balloon guide catheters may employ non-compliant or semi-compliant balloons that are inflated by pressure rather than using an inflation fluid. Specifically, non-compliant balloons are typically made from polyester or nylon when inflated with high pressure to dilate blood vessels or open blockages, while semi-compliant balloons made from materials such as Pebax or higher durometer polyurethanes are more flexible than non-compliant balloons when inflated with pressure, providing greater flexibility during delivery. Regardless of the type of balloon (flexible, semi-flexible, or non-flexible), bonding of the balloon to the outer surface of a catheter shaft during manufacture involves two competing criteria: maximizing bond strength and integrity, while simultaneously minimizing the profile / diameter at the bond interface where the balloon attaches to the catheter shaft. By way of example, the balloon guide catheter of the present invention is illustrated and described using a flexible, inflatable balloon for arresting blood flow through a blood vessel. It is understood that the present invention is applicable for use with any type of balloon (e.g., flexible, semi-flexible, or non-flexible). Figure 1 is a side view of a flexible, inflatable balloon sleeve 105 according to the present invention prior to assembly around a catheter shaft. The flexible, inflatable balloon 105 has a proximal bond interface region 110 and an opposing distal bond interface region 115, and the flexible, inflatable balloon 105 is securable around a catheter shaft 125 along the proximal and distal bond interfaces 110, 115. The proximal and distal bond boundaries each have a plurality of punctures 120 (eg, through-holes, holes, or openings) created, for example, with a fine punch tool or other mechanical device.The axial length of each of the proximal and distal bonding interface regions 110, 115 having the plurality of punctures defined therein is preferably between about 2 mm and about 3 mm.

[0013] A flexible, inflatable balloon 105 having multiple punctures 120 made in each of the proximal and distal bond boundaries 110, 115 is positioned externally around a catheter shaft 125, as shown in Figures 2A and 2B. A radial cross-section through an exemplary catheter shaft 125 showing its outer layer 130 is shown in Figure 3. The catheter shaft outer layer 130 is made of a reflowable material, preferably a material comprising medical-grade thermoplastic polyurethane (TPU) (e.g., Tecoflex®—a medical-grade aliphatic polyether-based thermoplastic polyurethane). The catheter shaft 125 may be designed to include any number of inner layers, one or more, positioned radially inward of the outer layer 130, if desired.

[0014] Preferably, certain regions of the flexible inflatable balloon 105, limited only to the area to be bonded to the catheter shaft (e.g., the proximal and distal bond interface regions 110 and 115 of the balloon sleeve, or the periphery of the balloon patch), are exposed to heat (e.g., thermally and / or laser-generated) to cause the outer layer 130 of the catheter shaft 125 to reflow / melt, which permeates / oozes upward through the punctures 120 (perforations, holes, openings) to form a radially outward reflow bond therebetween. As an illustrative example, heated jaws may be applied only around the perimeter of the area of ​​the flexible inflatable balloon to be bonded, thereby limiting the heating to a specific area or distance.

[0015] To further strengthen the bond of the balloon to the catheter shaft, an additional step may be performed in sequence or simultaneously with the formation of the radially outer reflow bond to form a complementary radially inner reflow bond using one or more reflow jackets / sleeves made of a reflow material, preferably a material comprising medical-grade thermoplastic polyurethane (TPU). Preferably, the reflow material of the one or more reflow jackets / sleeves and the reflow material of the outer layer of the catheter shaft are the same to ensure reflow of both materials upon exposure to heat at a predetermined temperature. Thus, reflow bonds are formed both radially inner and radially outer of the proximal and distal boundary bond regions of the flexible inflatable balloon. That is, upon heating, the reflowed / melted outer layer 130 of the catheter shaft 125 penetrates radially outward through the punctures 120 forming a radially outer reflow bond, while the reflowed / melted reflow jacket / sleeve 135, 140 seeps radially inward through the punctures 120 forming a radially inner reflow bond. The reflowed / melted material of the reflow jacket / sleeve 135, 140 and the enhanced reflow bonds (radially inner and radially outer) formed between the outer layer 130 of the catheter shaft 125 and into the punctures 120 on either side of the flexible inflatable balloon 105 optimizes bond integrity and strength while minimizing the possibility of leakage without increasing the outer diameter / profile.

[0016] 4A and 4B, two reflow jackets / sleeves are used, one disposed around each of the proximal and distal bond interface regions 110, 115 of the flexible inflatable balloon sleeve 105. That is, proximal reflow jacket / sleeve 135 is disposed around the flexible inflatable balloon coincident with / covering the proximal bond interface region 110, and distal reflow jacket / sleeve 140 is positioned around the flexible inflatable balloon coincident with / covering the distal bond interface region 115. The dashed lines in the side view of FIG. 4B indicate the proximal and distal edges 109, 114 of the flexible inflatable balloon 105, respectively, that are covered by the proximal and distal reflow jacket / sleeve 135, 140. A 360° radial gap 145 is formed between the proximal reflow jacket / sleeve 135 and the distal reflow jacket / sleeve 140, which are axially / longitudinally separated from one another. Preferably, the two reflow jackets / sleeves are each made of the same material as the outer layer 130 of the catheter shaft 125 to ensure reflow when heated to a predetermined temperature. When inflated with an inflation fluid, the exposed 360° radial area of ​​the flexible inflatable balloon patch 105 expands through the 360° radial gap 145 forming a radial bulge or radial expansion (e.g., a tire).

[0017] An alternative design using a single reflow jacket / sleeve 137 having cutouts or openings 138 defined therein is illustrated in the longitudinal cross-sectional and top views of FIGS. 5A and 5B, respectively. In this configuration, because a single reflow jacket / sleeve 137 is used, the cutouts or openings 138 defined in its axial / longitudinal sides extend radially less than 360°. The dimensions of the cutouts or openings 138 (both axial / longitudinal and radial / lateral) are slightly smaller than the circumference of the flexible inflatable balloon patch 105′. During assembly, the single reflow jacket / sleeve 137 is aligned with and positioned radially outward of the flexible inflatable balloon patch 105′, exposing a central region of the flexible inflatable balloon patch 105′ through the cutouts or openings 138. When inflated with inflation fluid, the exposed central region of the flexible inflatable balloon patch 105' expands through the cutouts or openings 138 to form lateral bulges or lateral expansions.

[0018] The various aspects, features, designs, and configurations of the present invention can be combined as desired for a given intravascular catheter, with the intended goal of improving the integrity and strength of the bond between the balloon and the catheter shaft while minimizing the profile or outer diameter of the assembled catheter.

[0019] Thus, while the essential novel features of the present invention as applied to the preferred embodiments thereof have been shown, described, and pointed out, those skilled in the art will recognize that various omissions, substitutions, and changes in the form and details of the illustrated systems / devices, and in their operation, may be made without departing from the spirit and scope of the present invention. For example, all combinations of elements and / or steps that perform substantially the same function in substantially the same way to achieve the same result are expressly intended to be encompassed within the scope of the present invention. Also, substitutions of elements from one described embodiment to another are fully intended and anticipated. It should also be understood that the drawings are not necessarily drawn to scale and are merely conceptual. It is therefore intended to be limited only by the scope of the appended claims.

[0020] All issued patents, pending patent applications, publications, articles, books, or other references cited herein are each incorporated herein by reference in their entirety.

[0021] [Embodiment] (1) A balloon guide catheter, a catheter shaft having an outer layer made of a reflowable material; a balloon having a bonded interface with a plurality of punctures defined therein, the balloon secured around the outer layer of the catheter shaft via penetration of the reflowable material of the outer layer into the plurality of punctures to form a radially outer reflow bond between the catheter shaft and the balloon; A balloon guide catheter, wherein the balloon is secured to the catheter shaft without adhesive. (2) A balloon guide catheter as described in embodiment 1, wherein the reflowable material of the outer layer comprises medical grade thermoplastic polyurethane. (3) A balloon guide catheter as described in embodiment 1, wherein the balloon is a sleeve, the bonded boundary region includes a proximal bonded boundary region and an opposite distal bonded boundary region, and the multiple punctures are radially arranged 360° within the proximal bonded boundary region and the distal bonded boundary region of the balloon sleeve. (4) A balloon guide catheter as described in embodiment 3, wherein each of the proximal and distal bonded boundary regions of the balloon sleeve having the multiple punctures defined therein is approximately 2 mm in the axial direction. (5) a proximal reflow jacket disposed around the balloon covering the proximal bond interface; a distal reflow jacket disposed around the balloon covering the distal bond interface, the distal reflow jacket being axially separated from the proximal reflow jacket to form a 360° radial gap between the distal reflow jacket and the proximal reflow jacket, with a portion of the balloon exposed; each of the proximal reflow jacket and the distal reflow jacket is made of a reflowable material, and the proximal reflow jacket and the distal reflow jacket are securable to the balloon via the reflowable material of the proximal outer jacket and the distal outer jacket that can penetrate into the plurality of punctures to form a radially inner reflow bond; 4. The balloon guide catheter of claim 3, wherein the proximal reflow jacket and the distal reflow jacket are secured to the balloon without adhesive.

[0022] (6) A balloon guide catheter as described in embodiment 5, wherein the reflowable material of the proximal reflow jacket and the distal reflow jacket is the same as the reflowable material of the outer layer of the catheter shaft. (7) A balloon guide catheter as described in embodiment 1, wherein the balloon is a patch or a sleeve. (8) A balloon guide catheter as described in embodiment 7, further comprising a single reflow jacket made of a reflowable material, the single reflow jacket having an opening defined therein aligned with the balloon, and the single reflow jacket being secured to the balloon along the bonding boundary region around the opening in the balloon by penetrating the reflowable material of the single reflow jacket into the multiple punctures in the balloon to form a radially inner reflow bond. (9) A balloon guide catheter according to embodiment 8, wherein the reflowable material of the single reflow jacket is the same as the reflowable material of the outer layer of the catheter shaft. (10) A method for assembling a balloon guide catheter, comprising: Drilling a plurality of punctures into a bonding interface region of the balloon that can be secured to an outer layer made of a reflowable material of the catheter shaft; placing the balloon having the plurality of punctures therein about the outer layer of the catheter shaft; and exposing the catheter shaft to heat along the bond interface to cause the reflowable material of the outer layer of the catheter shaft to penetrate into the plurality of punctures and form a radially outer reflow bond between the outer layer of the catheter shaft and the balloon; The method wherein the balloon is secured to the catheter shaft without adhesive.

[0023] 11. The method of claim 10, wherein the reflowable material of the outer layer comprises a medical-grade thermoplastic polyurethane. (12) The method of embodiment 10, wherein the balloon is a sleeve, the bonded boundary region includes a proximal bonded boundary region and an opposing distal bonded boundary region, and the plurality of punctures are radially arranged 360° within the proximal bonded boundary region and the distal bonded boundary region of the balloon sleeve. (13) The method of embodiment 12, wherein each of the proximal and distal bonded boundary regions of the balloon sleeve having the plurality of punctures defined therein is approximately 2 mm in the axial direction. (14) Positioning a proximal reflow jacket disposed around the balloon covering the proximal bond interface region and a distal reflow jacket disposed around the balloon covering the distal bond interface region, the distal reflow jacket is axially separated from the proximal reflow jacket to form a 360° radial gap between the distal reflow jacket and the proximal reflow jacket, with a portion of the balloon exposed; positioning the proximal reflow jacket and the distal reflow jacket, each made of a reflowable material; 14. The method of claim 13, further comprising: further securing the balloon to the outer layer of the catheter shaft by heating the reflow material of the proximal reflow jacket and the distal reflow jacket to penetrate into the plurality of punctures to form a radially inner reflow bond. 15. The method of claim 14, wherein the reflowable material of the proximal reflow jacket and the distal reflow jacket is the same as the reflowable material of the outer layer of the catheter shaft.

[0024] (16) positioning a single reflow jacket made of a reflowable material disposed around the balloon covering the bonded interface, the single reflow jacket having an opening defined therein aligned with the balloon; 16. The method of claim 15, further comprising: fixing the single reflow jacket to the balloon by heating the reflowable material of the single reflow jacket and causing it to infiltrate into the multiple punctures in the balloon along the bond boundary area around the openings in the balloon, thereby forming a radially inner reflow bond. 17. The method of claim 16, wherein the reflowable material of the single reflow jacket is the same as the reflowable material of the outer layer of the catheter shaft.

Claims

1. A balloon guide catheter, a catheter shaft having an outer layer made of a reflowable material; a balloon having a bonded interface with a plurality of punctures defined therein, the balloon secured around the outer layer of the catheter shaft via penetration of the reflowable material of the outer layer into the plurality of punctures to form a radially outer reflow bond between the catheter shaft and the balloon; the balloon is a balloon patch and is secured to the catheter shaft without adhesive; A balloon guide catheter further comprising a single reflow jacket made of a reflowable material, the single reflow jacket having an opening defined therein aligned with the balloon, and the single reflow jacket being secured to the balloon along the bonding boundary area around the opening in the balloon by penetrating the reflowable material of the single reflow jacket into the multiple punctures in the balloon to form a radially inner reflow bond.

2. The balloon guide catheter of claim 1 , wherein the reflowable material of the outer layer comprises a medical grade thermoplastic polyurethane.

3. The balloon guide catheter of claim 1 , wherein the reflowable material of the single reflow jacket is the same as the reflowable material of the outer layer of the catheter shaft.

4. 1. A method for assembling a balloon guide catheter, comprising: Drilling a plurality of punctures into a bonding interface region of the balloon that can be secured to an outer layer made of a reflowable material of the catheter shaft; placing the balloon having the plurality of punctures therein about the outer layer of the catheter shaft; and exposing the catheter shaft to heat along the bond interface to cause the reflowable material of the outer layer of the catheter shaft to penetrate into the plurality of punctures and form a radially outer reflow bond between the outer layer of the catheter shaft and the balloon; the balloon is a balloon patch and is secured to the catheter shaft without adhesive; positioning a single reflow jacket made of a reflowable material disposed around the balloon covering the bonded interface, the single reflow jacket having an opening defined therein that is aligned with the balloon; and fixing the single reflow jacket to the balloon by heating the reflowable material of the single reflow jacket and causing it to infiltrate into the multiple punctures in the balloon along the bond boundary area around the openings in the balloon to form a radially inner reflow bond.

5. The method of claim 4 , wherein the reflowable material of the outer layer comprises a medical grade thermoplastic polyurethane.

6. The method of claim 4 , wherein the reflowable material of the single reflow jacket is the same as the reflowable material of the outer layer of the catheter shaft.

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