Balloon guide catheter with increased balloon bond strength and minimized external profile

Abstract

The present invention is entitled "Balloon guide catheter with increased balloon bond strength and minimized external profile." The present invention provides a balloon guide catheter having a balloon bonded thereto to maximize bond strength and integrity while minimizing external profile. A return sheath is fused / embedded into a braided support structure of the catheter fixed beneath the balloon. Radially disposed apertures and / or recesses can be defined in the balloon through which adhesive can permeate upward when secured about the catheter shaft. Proximal and distal bond interface regions of the balloon can be square cut into two segments each extending radially 180°. Proximal and / or distal edges of the balloon can be inverted inward prior to being secured to the catheter shaft to form respective proximal and / or inverted bond portions. During preparation of the catheter, residual air can be vented from the balloon through a vent defined in the compliant balloon or a vent tube fixed between an outer surface of the catheter shaft and the balloon.

Description

BACKGROUND TECHNICAL FIELD

[0001] In procedures to capture and retrieve a thrombus, obstruction, or clot in a blood vessel using an intravascular catheter, a balloon can be used to stop blood flow or to dilate the blood vessel. The balloon is affixed to the catheter shaft of the balloon guide catheter of the present invention at a bonding interface region with minimal external profile / diameter and optimal bonding strength.

[0002] Related Art

[0003] Acute ischemic stroke is primarily caused by a thrombotic or embolic occlusion (e.g., blockage) in an artery of the brain. The occlusion is usually caused by a blood clot released from another part of the body that travels in an antegrade direction (in the direction of normal blood flow) through the blood vessels and eventually becomes lodged in an artery of the nervous system at a location where it blocks blood flow to an area of the brain.

[0004] A procedure known as thrombectomy can be used to remove a thrombus, obstruction, blockage, or clot lodged in a blood vessel using a mechanical retrieval device. During a thrombectomy procedure or treatment, a physician or interventionalist introduces a guidewire and microcatheter together through the vasculature endovascularly, usually in an artery located in the groin or arm, or directly through the carotid artery. The guidewire and microcatheter are advanced together to a location proximal to the target clot, blockage, or obstruction. The guidewire is then advanced through the clot, followed by the microcatheter. While in a compressed state, a mechanical thrombectomy device can be directed through the lumen of the microcatheter to the target site. Upon exiting the microcatheter, the mechanical thrombectomy device typically automatically expands to its initial enlarged state. The mechanical thrombectomy device is typically made of a self-expanding biocompatible material such as nickel titanium. Aspiration through the catheter can accompany or be used in place of the mechanical retrieval device to remove the clot.

[0005] During a thrombectomy procedure, a balloon guide catheter is often employed to stop blood flow by introducing inflation fluid into a compliant inflatable balloon made of an elastomeric material (e.g., polyurethane, polymer blend, or latex) rather than by pressurized inflation. The ability of a compliant inflatable balloon to conform to the shape of the vasculature makes it particularly suitable for use in stopping blood flow. In other applications, such as dilating a blood vessel or opening an obstruction, a balloon guide catheter can employ a non-compliant or semi-compliant balloon that inflates by pressurization rather than using inflation fluid. Specifically, a non-compliant balloon, typically made of polyester or nylon, dilates a blood vessel or opens an obstruction when inflated under high pressure; while a semi-compliant balloon, made of a material such as Pebax or higher durometer polyurethane, is more compliant than a non-compliant balloon when inflated by pressurization, thereby providing greater flexibility during delivery. Regardless of the type of balloon (compliant, semi-compliant, or non-compliant), there are two competing criteria in the manufacturing process of bonding the balloon to the outer surface of the catheter shaft, namely, minimizing the external profile / diameter at the bond interface region where the balloon is mounted to the catheter shaft, while maximizing the bond strength and integrity.

[0006] It is desirable to design an improved balloon guide catheter having a bond interface region between the balloon and the outer surface of the catheter shaft to achieve optimal bond strength and integrity while minimizing the external profile or outer diameter. SUMMARY

[0007] One aspect of the present invention relates to an improved balloon guide catheter having a balloon (compliant, semi-compliant, or non-compliant) bonded to the catheter with maximized bond strength and integrity while minimizing the external profile or outer diameter.

[0008] Another aspect of the present invention relates to a balloon guide catheter having a catheter shaft with a central lumen longitudinally defined therein and an inflation lumen substantially parallel to the central lumen; the catheter shaft having a braid supporting the central lumen and the inflation lumen. A balloon is disposed about the braid. At least one backflow sheath made of a material capable of backflowing into the braid secures the balloon to the catheter shaft, wherein an exposed portion of the balloon is not covered by the at least one backflow sheath.

[0009] Another aspect of the present invention relates to a balloon guide catheter comprising a catheter shaft and a balloon disposed about the catheter shaft. The balloon is secured to the catheter shaft at a distal bond interface region and an opposing proximal bond interface region, wherein the balloon has a plurality of radially arranged apertures and / or recesses defined in each of the distal bond interface region and the proximal bond interface region of the balloon. An adhesive disposed about the outer surface of the catheter shaft is capable of penetrating upward into the plurality of radially arranged apertures and / or recesses in the balloon.

[0010] Yet another aspect of the present invention relates to a balloon guide catheter comprising a catheter shaft having an outer surface and a balloon disposed about the outer surface of the catheter shaft. The balloon has a turned distal bond interface region comprising a turned distal edge and / or an opposite turned proximal bond interface region comprising a proximal edge. The turned distal bond region and / or the interface turned proximal bond interface region of the balloon are secured to the outer surface of the catheter shaft by an adhesive.

[0011] Still another aspect of the present invention relates to a balloon guide catheter comprising a catheter shaft and a balloon sleeve disposed about the catheter shaft. The balloon is secured to the catheter shaft at a cut distal bond interface region and / or an opposite cut proximal bond interface region. The cut distal bond interface region and / or the cut proximal bond interface region of the balloon are secured to the catheter shaft by an adhesive.

[0012] Another aspect of the present invention relates to a balloon guide catheter comprising a catheter shaft having an outer surface and a balloon disposed about the catheter shaft. The balloon is secured to the catheter shaft with a vent tube secured between the compliant inflatable tube and the outer surface of the catheter shaft.

[0013] Still another aspect of the present invention relates to a balloon guide catheter comprising a catheter shaft and a balloon disposed about the catheter shaft. The balloon is secured to the catheter shaft at a distal bond interface region and an opposite proximal bond interface region; wherein the balloon has a vent hole defined between the proximal bond interface region and the distal bond interface region. The balloon is transformable into an inflated state wherein a portion of the balloon is extendable over at least one of the respective proximal bond interface region and the distal bond interface region into physical contact with the outer surface of the catheter shaft thereby sealing the vent hole. BRIEF DESCRIPTION OF DRAWINGS

[0014] The above-described and other features of the present invention will become more apparent from the following detailed description and accompanying drawings, in which:

[0015] FIG. 1A is a partial axial section view of a first configuration of the balloon catheter of the present invention in which the distal and proximal edges of the compliant inflatable balloon sleeve (shown in a non-inflated state) are secured under respective distal and proximal reflux sheaths / sleeves that are axially separated from one another to form a 360° radial gap therebetween to expose a portion of the compliant inflatable balloon guide sleeve;

[0016] FIG. 1B is a radial section view through the proximal reflux sheath / sleeve in FIG. 1A is a radial section view through the proximal reflux sheath / sleeve in

[0017] FIG. 1C is a radial cross-sectional view taken along line I(C)-I(C) in FIG. 1A , the sheath / sleeve securing the distal edge of the compliant inflatable balloon sleeve to the outer surface of the catheter shaft;

[0018] FIG. 2A is a partial axial cross-sectional view of another configuration of the balloon guide catheter of the present invention, wherein the compliant inflatable balloon (shown in non-inflated state) is secured beneath a single backflow sheath / sleeve having a cutout or opening defined therein, thereby exposing a portion of the compliant inflatable balloon;

[0019] FIG. 2B is a top view of the balloon guide catheter of FIG. 2A , wherein the compliant inflatable balloon is in a non-inflated state;

[0020] FIG. 2C is a distal perspective view of the balloon guide catheter of FIG. 2B , wherein the compliant inflatable balloon is in an inflated state, thereby protruding radially outward through the cutout or opening defined in the single backflow sheath / sleeve;

[0021] FIG. 3 is a partial longitudinal cross-sectional view of another configuration of the balloon guide catheter of the present invention, wherein the braid configured as an "8" shape (braided above and below the inflation lumen and surrounding the central lumen) terminates proximal to the distal end of the inflation lumen so as not to coincide with the single backflow sheath / sleeve, thereby minimizing the external profile;

[0022] FIG. 4A is a partial side view of the proximal junction interface region of the compliant inflatable balloon having a plurality of radial slits defined therein, wherein the balloon is shown in an inflated state;

[0023] FIG. 4B is a partial proximal end perspective view of the compliant inflatable balloon of FIG. 4A ;

[0024] FIG. 4C is a partial side view of the proximal junction interface region of the compliant inflatable balloon having a plurality of radially arranged apertures defined therein, wherein the balloon is shown in an inflated state;

[0025] FIG. 4D is a longitudinal cross-sectional view of the compliant inflatable balloon of FIG. 4A , assembled onto a catheter shaft;

[0026] FIG. 5Ais a partial longitudinal section view of a prior art balloon guide catheter having a compliant inflatable balloon sleeve secured to the outer surface of the catheter shaft along its non-inverted proximal bond interface region and non-inverted distal bond interface region using adhesive;

[0027] FIG. 5B is a partial longitudinal section view of a balloon guide catheter of the present invention having a compliant inflatable balloon sleeve secured to the outer surface of the catheter shaft along its inverted proximal bond interface region and inverted distal bond interface region using adhesive;

[0028] FIG. 5C is a partial longitudinal section view of a balloon guide catheter of the present invention having a compliant inflatable balloon sleeve secured to the outer surface of the catheter shaft along its non-inverted proximal bond interface region and inverted distal bond interface region using adhesive;

[0029] FIG. 6A is a partial side view of yet another configuration of a balloon guide catheter of the present invention showing a truncated proximal bond interface region of a compliant inflatable balloon sleeve including a truncated proximal bond first segment extending radially less than 360° (preferably about 180°) around the circumference of the catheter shaft, and a truncated proximal bond second segment extending radially less than 360° (preferably about 180°) around the circumference of the catheter shaft;

[0030] FIG. 6B is a radial section view of the truncated proximal bond first segment of the truncated proximal bond interface region of the compliant inflatable balloon of FIG. 6A

[0031] FIG. 6C is a radial section view of the truncated proximal bond second segment of the truncated proximal bond interface region of the compliant inflatable balloon of FIG. 6A

[0032] FIG. 6D shows a flattened truncated proximal bond interface region of the compliant inflatable balloon of FIG. 6A

[0033] FIG. 6E ​​​A substitute design for the flat cut proximal junction interface region of a compliant inflatable balloon is shown that includes: (i) a cut proximal junction first segment that extends less than 360° (preferably about 180°) radially around the circumference of the catheter shaft; (ii) a cut proximal junction second segment that extends less than 360° (preferably about 180°) radially around the circumference of the catheter shaft; and (iii) a non-cut proximal junction third segment disposed between the cut proximal junction first and second segments that extends 360° radially around the circumference of the catheter shaft;

[0034] FIG. 7 is a partial longitudinal section view of a marker band physically curled around a proximal reflux sheath / sleeve that secures the proximal edge of the compliant inflatable balloon sleeve to the outer surface of the catheter shaft;

[0035] FIG. 8A is a partial longitudinal section view of a compliant inflatable balloon with a longitudinal vent tube secured between the proximal junction interface region of the compliant inflatable balloon and the outer surface of the catheter shaft, wherein the balloon is shown in an inflated state;

[0036] FIG. 8B is a partial longitudinal section view of a compliant inflatable balloon with a vent hole defined in the compliant inflatable balloon proximal to the non-inverted proximal junction interface region of the compliant inflatable balloon secured to the outer surface of the catheter shaft, wherein the compliant inflatable balloon is shown in a partially inflated state;

[0037] FIG. 8C is a partial longitudinal section view of the compliant inflatable balloon of FIG. 8B in a further inflated state, showing a portion of the compliant inflatable balloon extending in a proximal direction over the non-inverted proximal junction interface region and in physical contact with the outer surface of the catheter shaft, thereby sealing the vent hole and preventing inflation fluid from exiting the vent hole;

[0038] FIG. 8D is a partial longitudinal section view of another configuration of a compliant inflatable balloon with a vent hole defined in the compliant inflatable balloon proximal to the inverted proximal junction interface region, wherein the compliant inflatable balloon is secured to the outer surface of the catheter shaft, wherein the balloon is shown in a partially inflated state; and

[0039] FIG. 8E is a partial longitudinal section view of the compliant inflatable balloon of FIG. 8D in a further inflated state, showing a portion of the compliant inflatable balloon extending in a proximal direction over the inverted proximal junction interface region and in physical contact with the outer surface of the catheter shaft, thereby sealing the vent hole and preventing inflation fluid from exiting the vent hole. DETAILED DESCRIPTION

[0040] The terms "distal" or "proximal" are used in the following description in relation to position or orientation relative to a treating physician or medical interventionist. "Distal" or "distally" is a position away from or in a direction away from the physician or interventionist. "Proximal" or "proximally" or "proximate" is a position close to or in a direction toward the physician or medical interventionist. The terms "occlusion," "embolus," or "embolization" are used interchangeably.

[0041] The present invention relates to several different features, designs, and configurations for an intravascular catheter having a balloon for blocking blood flow through or dilating a blood vessel, wherein the integrity and strength of the bond between the fixed balloon and the catheter shaft is optimized while the external profile / diameter is minimized. As an illustrative example, the balloon-guided catheter of the present invention is shown and described as having a compliant inflatable balloon. However, it is within the contemplation of the present invention for the balloon-guided catheter of the present invention to employ any type of balloon (compliant, semi-compliant, or non-compliant).

[0042] The compliant inflatable balloon can be a sleeve or patch that is fixed or captured to the outer surface of the catheter shaft beneath one or more backflow sheaths or sleeves. FIGS. 1A-1C A first design of the balloon-guided catheter of the present invention is shown, wherein the opposing edges of the compliant inflatable balloon sleeve 130 are fixed or captured to the outer surface of the catheter shaft 105 by separate, respective backflow sheaths / sleeves 120, 125. In this design, the backflow sheaths / sleeves 120, 125 are fixed or captured to the outer surface of the catheter shaft 105 by a plurality of circumferentially spaced apart fasteners 150, 155. FIG. 1A A partial longitudinal cross-sectional view of the balloon-guided catheter 100 according to this first configuration is shown in FIG. 1. The catheter shaft 105 includes an inner liner or lining 107 that forms an axially extending central lumen 106. A support layer 110 (e.g., braid, mesh, cage, or hypotube) is disposed radially outwardly and surrounds the inner liner or lining 107, providing support and kink resistance for the central lumen 106 and an inflation lumen 115 that extends substantially parallel thereto. In the example shown in the figures, the support layer is a braid 110. Preferably, the braid 110 encircles the central lumen 106 and is woven in an "8" shaped configuration above and below the inflation lumen 115, as shown in the radial cross-sectional view of FIG. 2. The braid 110 encircles the entire length of the central lumen 106 (FIG. 2). FIG. 1B FIG. 1C The braid 110 around the catheter shaft 105 is provided with an inflatable compliant balloon sleeve 130 having a proximal edge 135 disposed proximally and opposite a distal edge 140.

[0043] ​Two reflow shrouds or sleeves are disposed about the catheter shaft. Specifically, a distal reflow shroud / sleeve 125 is arranged distally of the proximal reflow shroud / sleeve 120 and is axially spaced therefrom by a predetermined distance, defining a 360° radial gap 116 therebetween. The proximal reflow shroud / sleeve 120 and the distal reflow shroud / sleeve 125 are positioned to cover respective proximal and distal edges 135, 140 of the compliant inflatable balloon sleeve 130, while a central radial portion of the compliant inflatable balloon sleeve 130 remains exposed through the 360° radial gap 116. In the illustrated example embodiment, the proximal reflow shroud / sleeve 120 is radially outwardly disposed so as to cover the proximal edge 135 of the compliant inflatable balloon sleeve 130, while the distal reflow shroud / sleeve 125 is radially outwardly disposed so as to cover the distal edge 140 of the compliant inflatable balloon sleeve 130. Multiple proximal reflow shrouds / sleeves can be stacked in a radially outward direction so as to cover the proximal edge 135 of the compliant inflatable balloon sleeve 130 and reflow onto (embed within) the braid 110, while multiple distal reflow shrouds / sleeves can be stacked in a radially outward direction so as to cover the distal edge 140 of the compliant inflatable balloon sleeve 130 and reflow onto (embed within) the braid 110. In the case of multiple reflow shrouds / sleeves covering each of the proximal and distal edges of the compliant inflatable balloon, each reflow shroud / sleeve can be independently reflowed, with each reflow shroud / sleeve being positioned and heated sequentially one after the other. That is, a first or inner reflow shroud / sleeve (proximal and distal) is heated to reflow onto (embed within) the braid 110 after being positioned about the respective proximal and distal edges of the compliant inflatable balloon. Thereafter, a second or outer reflow shroud / sleeve (proximal and distal) is heated to reflow onto the respective first reflow shroud / sleeve after being positioned thereabout. Alternatively, a single reflow process can be employed whereby the first (inner) and second (outer) reflow shrouds / sleeves are heated simultaneously once positioned, simultaneously causing the material to reflow. FIG. 1A In the illustrated example embodiment, a single proximal reflow shroud / sleeve 120 is radially outwardly disposed so as to cover the proximal edge 135 of the compliant inflatable balloon sleeve 130, while a single distal reflow shroud / sleeve 125 is radially outwardly disposed so as to cover the distal edge 140 of the compliant inflatable balloon sleeve 130. Multiple proximal reflow shrouds / sleeves can be stacked in a radially outward direction so as to cover the proximal edge 135 of the compliant inflatable balloon sleeve 130 and reflow onto (embed within) the braid 110, while multiple distal reflow shrouds / sleeves can be stacked in a radially outward direction so as to cover the distal edge 140 of the compliant inflatable balloon sleeve 130 and reflow onto (embed within) the braid 110. In the case of multiple reflow shrouds / sleeves covering each of the proximal and distal edges of the compliant inflatable balloon, each reflow shroud / sleeve can be independently reflowed, with each reflow shroud / sleeve being positioned and heated sequentially one after the other. That is, a first or inner reflow shroud / sleeve (proximal and distal) is heated to reflow onto (embed within) the braid 110 after being positioned about the respective proximal and distal edges of the compliant inflatable balloon. Thereafter, a second or outer reflow shroud / sleeve (proximal and distal) is heated to reflow onto the respective first reflow shroud / sleeve after being positioned thereabout. Alternatively, a single reflow process can be employed whereby the first (inner) and second (outer) reflow shrouds / sleeves are heated simultaneously once positioned, simultaneously causing the material to reflow.

[0044] During assembly, the compliant inflatable balloon sleeve 130 is positioned around the catheter shaft 105. Thereafter, the proximal backflow sheath / sleeve 120 and the distal backflow sheath / sleeve 125 are positioned over the compliant inflatable balloon sleeve 130 to cover the respective proximal edge 135 and distal edge 140, while the central 360° radial portion of the compliant inflatable balloon sleeve 130 remains exposed through the 360° radial gap 116. During backflow, a protective covering (e.g., tape) is positioned to cover at least the 360° radial gap 116 to protect the exposed portion of the compliant inflatable balloon sleeve 130 (i.e., the portion of the compliant inflatable balloon sleeve that is not covered by the backflow sheath / sleeve) from heat exposure during backflow. Preferably, the protective covering extends beyond the balloon, e.g., the protective covering sleeve extends in the axial direction beyond the proximal and distal edges on both sides of the compliant inflatable balloon. The protective covering is preferably a heat resistant material, e.g., heat shrink material (e.g., polyethylene terephthalate (PET), fluorinated ethylene propylene (FEP)) whose properties ensure that it remains in place. Non-heat shrink materials (e.g., polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK)) can be used as the protective covering, which is secured in place, e.g., by an external tape or sleeve made of heat shrink material. The assembled catheter shaft is then heated using heat and / or laser, causing the proximal backflow sheath / sleeve 120 and the distal backflow sheath / sleeve 125 to backflow melt together with the respective proximal edge 135 and distal edge 140 of the compliant inflatable balloon 130, thereby forming a leak-proof seal with the braid 110 of the catheter shaft 105. After backflow, the protective covering is removed. Injection of a biocompatible inflation fluid (e.g., contrast saline solution) through the inflation lumen 115 causes the compliant inflatable balloon to inflate only within the 360° radial gap 116. Thus, a 360° radial inflation bulge (e.g., a tire-like portion) of the compliant inflatable balloon is created in the 360° radial gap 116 between the proximal backflow sheath / sleeve 120 and the distal backflow sheath / sleeve 125.

[0045] FIGS. 2A-2C A minor variation of the foregoing configuration of the present balloon guide catheter is depicted in FIGS. 1A-1C instead of employing two (e.g., proximal and distal) backflow sheaths / sleeves that are axially separated to define a 360° radial gap, a single backflow sheath / sleeve 223 is employed that has a cutout or opening 216 (e.g., a side opening) defined therein that extends radially less than 360°. In FIG. 2AA partial longitudinal cross-sectional view of a balloon guide catheter 200 according to this improved construction is shown in FIG. 1. The catheter shaft 205 includes an inner liner or liner 207 that forms an axially extending central lumen 206. A support layer 210 (e.g., braid, mesh, cage, or hypotube) is disposed radially outward and encloses the inner liner or liner 207, supporting the central lumen 206 and an inflation lumen 215 that are disposed generally parallel to each other. In the example shown in the figure, the support layer is a braid 210 of similar construction to that in FIGS. 1A-1C A compliant inflatable balloon patch 230 having a circumference is placed over the braid 210 of the catheter shaft 205. A single backflow sheath or sleeve 223 defines a cutout or opening 216 therein that extends less than 360° radially, which is generally aligned with the compliant inflatable balloon patch 230. The cutout or opening 216 is sized to be less than the circumference of the compliant inflatable balloon patch 230, exposing only a portion of the balloon patch through the cutout or opening. A rectangular cutout or opening 216 is shown, but any desired shape can be used, such as but not limited to a square, circular, or oval. FIG. 2B is a top view of the assembled balloon guide catheter 200, showing the cutout or opening 216 in the single backflow sheath / sleeve 223, exposing a portion of the compliant inflatable balloon 230 (shown in a non-inflated state - its outer perimeter is represented by a dashed line). Injection of a biocompatible inflation fluid (e.g., contrast saline) through the inflation lumen 215 causes the fixed compliant inflatable balloon 230 to inflate only within the cutout or opening 216. Thus, an inflated "side" bulge (i.e., a "side inflation bulge" that extends less than 360° radially) of the compliant inflatable balloon is created in the cutout or opening 216 of the backflow sheath / sleeve 223. Once the catheter is inserted into a blood vessel at a target site, the balloon is inflated, creating a deflected inflation ("side bulge") to block blood flow through, while minimizing an increase in the external profile or outer diameter of the assembled catheter.

[0046] In the backflow sheath / sleeve constructions shown and described above FIGS. 1A-1C and FIGS. 2A-2C in FIGS. 1-4, each of the central lumen and the inflation lumen are supported by the braid 210 (e.g., support layer) that extends to their respective distal ends. Referring to FIG. 1, the braid 110 supports (i.e., braids above and below) the inflation lumen 115 to its distal end (e.g., discharge port), which coincides with the 360° radial gap 116 between the two separate distal backflow sheaths / sleeves 120 and the proximal backflow sheath / sleeve 125. Similarly, in FIG. 4, the braid 410 supports (i.e., braids above and below) the inflation lumen 415 to its distal end (e.g., discharge port), which coincides with the 360° radial gap 416 between the two separate distal backflow sheaths / sleeves 420 and the proximal backflow sheath / sleeve 425. FIG. 1A FIG. 2A ​In this case, the braid 210 supports (i.e., braids over and under) the inflation lumen 215 to its distal end (e.g., the discharge port), which coincides with the cutout or opening 216 defined in the single reflux sheath / sleeve 223. In either design, this support provided by the braid to the distal end of the inflation lumen disadvantageously increases the overall outer profile (outer diameter) of the compliant inflatable balloon at the proximal interface junction region fixed to the reflux sheath / sleeve.

[0047] Referring to FIG. 3 In this case, the braid 210 supports (i.e., braids over and under) the inflation lumen 215 to its distal end (e.g., the discharge port), which coincides with the cutout or opening 216 defined in the single reflux sheath / sleeve 223. In either design, this support provided by the braid to the distal end of the inflation lumen disadvantageously increases the overall outer profile (outer diameter) of the compliant inflatable balloon at the proximal interface junction region fixed to the reflux sheath / sleeve. FIG. 3 In this case, the portion of the distal end of the inflation lumen 315 that extends in the proximal direction from the discharge port 312 (distal tip or end) to the proximal edge of the single reflux sleeve / sheath 323 is not braided (e.g., supported by a braid) (not supported by a braid). That is, the shortening of the “upper” braid 310 (i.e., the braid that braids over and under the inflation lumen) in the distal direction is such that it does not coincide with the single reflux sheath / sleeve 323 (i.e., stops before reaching or upon reaching the reflux sheath / sleeve). Note that the illustrated embodiment is of a single reflux 323 sheath / sleeve in which a cutout or opening 316 is defined; however, this feature of the inflation lumen not being supported at its coincidence with the reflux sheath / sleeve also applies to designs employing two reflux sheaths / sleeves that are axially separated to form a 360° radial gap therebetween (as shown in FIGS. 1A-1C therefore, in either design (e.g., single reflux sheath / sleeve with a single opening or two reflux sheaths / sleeves axially separated to form a 360° radial gap therebetween), in the region of coincidence with the reflux sheath / sleeve, the inflation lumen 315 is not supported by the braid 310 (i.e., the braid 310 is not braided over and under the inflation lumen), thereby minimizing the overall outer profile (outer diameter) of the assembled balloon guide catheter. Unlike the inflation lumen 315, the central lumen 306 is preferably supported by the braid 310 from the proximal end to the distal end.

[0048] By defining a plurality of apertures (radial slits, holes, or other geometries) and / or recesses (dimples) radially disposed in each of the proximal and distal junction interface regions of the compliant inflatable balloon fixed to the outer surface of the catheter shaft, improved wetting and bond strength can be achieved. FIG. 4A and FIG. 4Brespectively, of a compliant inflatable balloon sleeve proximal end with a plurality of openings (e.g., radial slits 401) defined therethrough in the proximal bond interface region 487 (the distal bond interface region has a similar plurality of openings defined therein). The shape of each opening can be a radial slit 401 (as shown in FIG. 4A and FIG. 4B ) or a circular hole 401'(as shown in FIG. 4C ) or any other geometry defined by the balloon. All of the plurality of openings can have the same shape and size, but variations in shape and / or size are also possible. Any number of one or more rows of radially arranged openings can be provided, where adjacent rows can be radially offset or aligned with one another.

[0049] Prior to assembly, the plurality of openings are formed in the respective proximal and distal bond interface regions of the compliant inflatable balloon sleeve 430 using drilling, firing, laser etching, etc. Thereafter, when in the uninflated state, the compliant inflatable balloon sleeve 430 is positioned around the outer surface of the catheter shaft 405. The respective proximal and distal edges of the compliant inflatable balloon 430 are rolled toward one another, thereby exposing the underlying outer surface of the catheter shaft 405. A biocompatible adhesive 433 is applied around the exposed outer surface of the catheter shaft 405, and then the proximal and distal edges of the compliant inflatable balloon 430 are unrolled over the applied biocompatible adhesive 433, or the adhesive wicks up through the openings 401 defined in the compliant inflatable balloon 430, as shown in the longitudinal cross-sectional view of FIG. 4D It is also possible for the adhesive 433 to wick beyond the radial thickness of the openings, or to penetrate into the compliant inflatable outer surface balloon sleeve 430 in the regions adjacent to the openings. In the configuration shown in FIGS. 4A-4C , a plurality of openings (e.g., radial slits or circular holes) are defined through the compliant inflatable balloon (extending from the inner surface to the outer surface of the balloon). Alternatively, the compliant inflatable balloon can be designed to have a plurality of recesses (dimples) defined along the inner surface of the compliant inflatable balloon that do not extend through to the outer surface of the compliant inflatable balloon (closed at the outer surface). The recesses can be sufficient to allow the adhesive to pool therein, but since they are closed at the outer surface of the compliant inflatable balloon, the adhesive is prevented from flowing onto the outer surface. In another possible configuration, a combination of openings and recesses can be defined in the inflatable compliant balloon. The openings and / or recesses can extend a predetermined length in the longitudinal direction to constrain / limit / control the bond length / dimension by the adhesive flowing / pooling therein. Thus, during the manufacturing process, the adhesive is only pooled within the openings and / or recesses, which allows the bond length to be controlled without increasing the bonded outer profile.

[0050] Another aspect of the balloon catheter of the present invention is to maintain the integrity and maximum strength of the bond formed between the compliant inflatable guide balloon and the outer surface of the catheter shaft. Delamination of the fixed proximal and / or distal edges of the compliant inflatable balloon sleeve upon inflation is problematic and can result in reduced bond integrity and, in turn, failure. FIG. 5A A conventional non-inverted bond of a compliant inflatable balloon sleeve to the outer surface of a catheter shaft in the prior art is shown. Upon over-inflation, the compliant balloon can expand or inflate under this conventional non-inverted bond, resulting in possible undesirable delamination along such bond. To minimize the occurrence of delamination during inflation, the compliant inflatable outer surface balloon sleeve of the present invention is preferably adhered to the catheter shaft by an inverted bond along the proximal edge, the distal edge, or both edges. Due to the inverted bond, any expansion of the compliant inflatable balloon due to over-inflation does not result in delamination. FIG. 5B is an exemplary configuration of a compliant inflatable balloon sleeve 530, whose proximal and distal edges are inverted (e.g., retracted, inverted, folded, or bent inward) prior to being affixed to the outer surface of a catheter shaft 505 by a biocompatible adhesive 533. However, FIG. 5C is an alternative configuration in which only a single edge (e.g., the distal bond or the proximal bond) of the compliant inflatable outer surface balloon sleeve 530 is inverted (e.g., turned over, folded inward) prior to being affixed to the catheter shaft 505 by the adhesive 533. In both configurations, FIG. 5B and 5C), the compliant inflatable balloon sleeve 530 has an inner / inside surface (radially inward toward the catheter shaft) and an outer / outside surface (radially outward away from the catheter shaft) during the assembly process initially positioned around the outer surface of the catheter shaft. Next, the proximal portion (including the proximal edge) and / or the distal portion (including the distal edge) of the compliant inflatable balloon sleeve 530 are turned inside out, inverted, folded, tucked, bent or tucked inward onto itself, whereupon the turned inside out, inverted, folded, tucked or tucked inward portion (now radially inward toward the catheter shaft) is adhered to the outer surface of the catheter shaft, thereby forming a turned inside out junction. The two opposing turned inside out portions of the compliant inflatable interface balloon sleeve are referred to as a proximal turned inside out junction region and a distal turned inside out junction region, which are each secured to the outer surface of the catheter shaft by adhesive, thereby forming a turned inside out proximal junction and a turned inside out distal junction. Preferably, the turned inside out proximal junction interface region of the compliant inflatable balloon includes the proximal edge and is about 1 mm in length in the axial direction; and the turned inside out distal junction interface region of the compliant inflatable balloon includes the distal edge and is about 1 mm in length in the axial direction. Any desired length of each turned inside out junction interface region (proximal or distal) in the axial direction can be selected depending on the desired outer profile or outer diameter of the assembled catheter. That is, the shorter the axial length of the turned inside out junction interface region (proximal or distal), the greater the outer profile or outer diameter. The length of each turned inside out junction interface region (proximal or distal) in the axial direction can be the same, but need not be. Residual air in the balloon can be purged in different ways. One way is to have a vent hole or air release hole in the balloon near the turned inside out junction, which expands outward over the vent hole when the balloon is inflated, thereby creating a seal. Other preparatory steps for purging residual air can be employed, such as repeatedly inflating / deflating the balloon (typically holding the catheter with the balloon pointing downward, sometimes requiring flicking the balloon) until sufficient residual air is expelled.

[0051] As FIG. 5B and FIG. 5CThe overexpansion, as indicated by the downward arrow in FIG. 6, causes the compliant inflatable balloon sleeve to increase in size with the increase in pressure therein, exerting a downward force on the inverted bond interface region (distal and / or proximal) pushing the inverted portion of the balloon against the outer surface of the catheter shaft, thereby minimizing delamination. This inverted bond configuration enhances the integrity of the bond, wherein the increase in the outer profile or outer diameter of the assembled catheter is negligible. Furthermore, positioning the distal inverted bond proximate the distal tip of the catheter can advantageously result in the inflated compliant balloon protruding distally beyond the distal tip of the catheter, which is particularly suitable for certain treatments. When the compliant inflatable balloon extends to or beyond the distal tip of the catheter, protection can be provided during delivery, as the flexible compliant balloon material is now the leading edge of the catheter shaft, rather than a harder, less flexible, less compliant material. Furthermore, if suction through the primary guidewire lumen of the catheter is employed during clot extraction, the inflated portion of the balloon extending beyond the distal tip acts as a funnel to direct clots into the primary lumen of the shaft, to minimize shearing, occlusion, or occlusion of the clots.

[0052] Another configuration requires a beveled bond interface region between the compliant inflatable balloon and the outer surface of the catheter shaft. As an illustrative example, FIG. 6A The balloon depicted in FIG. 6 is a compliant inflatable balloon, however, this configuration is suitable for other types of balloons (e.g., semi-compliant or non-compliant). The compliant inflatable interface balloon sleeve 630 is affixed to the outer surface of the catheter shaft 605 along a beveled proximal bond region 610 (inverted relative to FIG. 6A as shown in the side view of FIG. 6) and / or an opposing beveled distal bond interface region (inverted relative to FIG. 6A as shown in the mirror image of FIG. 6) wherein each beveled proximal and / or distal bond interface region is beveled at a right angle (in the axial / longitudinal direction). FIG. 6A The beveled proximal bond interface region 610 of the exemplary compliant inflatable balloon sleeve 630 shown in FIG. 6 is divided into two segments, a beveled proximal bond first segment 615 disposed proximally of a beveled proximal bond second segment 620. Specifically, the beveled proximal bond first segment 615 extends radially less than 360° (preferably about 180°) around the circumference of the catheter shaft 605 (as shown in the radial cross-sectional view of FIG. 6), and the beveled proximal bond second segment 620 extends radially less than 360° (preferably 180°) around the circumference of the catheter shaft 605 (as shown in the radial cross-sectional view of FIG. 6). The beveled proximal bond second segment 620 preferably comprises the proximal edge of the compliant inflatable balloon 630 and extends in the distal direction toward the beveled proximal bond first segment 615. The beveled proximal bond first segment 615 and second segment 620 are radially offset relative to one another, preferably with minimal or no radial overlap between the adjoining bond segments (as shown in the radial cross-sectional view of FIG. 6). FIG. 6B FIG. 6C FIG. 6D ​​The middle is clearly visible, which shows FIG. 6A the flat cut proximal bonding interface portion 610) of the compliant inflatable balloon. Referring to the radial cross-sectional view in FIG. 6B the cut proximal first portion 615 radially covers 180° around the outer surface of the catheter shaft 605, leaving the remaining 180° of the catheter shaft 605 exposed (not covered). Likewise, FIG. 6C the radial cross-sectional view in FIG. 6B and FIG. 6C the biocompatible adhesive 633 is only applied to those areas on the outer surface of the catheter shaft 605 that are covered by the respective cut proximal bonding first and second segments 615 and 620. To further enhance the bonding, the cut proximal bonding first and second segments can be treated with heat bonding or laser bonding. By way of example, FIGS. 6A-6C shows that each bonding interface region (proximal and distal) includes two cut segments, each cut segment radially extending 180° around the circumference of the catheter shaft. There can be more than two cut segments at each bonding interface region, such as three cut segments, each cut segment radially extending 120° around the circumference of the catheter shaft; or four cut segments, each cut segment radially extending 90° around the circumference of the catheter shaft.

[0053] slightly different from FIGS. 6A-6C to further enhance the bonding between the balloon and the catheter shaft, each cut proximal and distal bonding interface region can include a non-cut third radial segment 618 that radially extends 360° around the outer surface of the catheter shaft. By way of illustrative example, the non-cut third radial segment 618 can be disposed in the axial / longitudinal direction between the cut first and second radial segments 615 and 620, which respectively radially extend 180° around the circumference of the catheter shaft. FIG. 6EA flattened proximal bond region 610' of a compliant inflatable balloon having this alternative design is shown. The axial length "AL" of the non-cut third radial segment 618 is very small (e.g., less than or equal to about 0.5 mm), representing a negligible increase in the outer profile or outer diameter of the assembled catheter, with no appreciable negative impact during use of the catheter. Thus, the non-cut third radial segment 618 provides enhanced 360° radial bonding between the compliant inflatable balloon and the outer surface of the catheter shaft, with negligible enlargement of the outer profile or outer diameter of the assembled catheter. The positioning or placement of the non-cut third radial segment extending 360° around the outer surface of the catheter shaft can vary. The cut first and second radial segments can abut one another, with the non-cut third radial segment abutting the free edge of one of the cut first or second radial segments, rather than being disposed between the cut first and second radial segments 615', 620' (as shown, for example, in FIGS. 6A-6C). These radially staggered or offset cut portions of each of the proximal and distal bond interface regions minimize the outer profile or outer diameter of the assembled catheter, while cumulatively maintaining 360° secure bonding around the outer surface of the catheter shaft. FIG. 6E These radially staggered or offset cut portions of each of the proximal and distal bond interface regions minimize the outer profile or outer diameter of the assembled catheter, while cumulatively maintaining 360° secure bonding around the outer surface of the catheter shaft.

[0054] To further reduce the occurrence of peeling, the non-inverted bond between the balloon and the outer surface of the catheter shaft can be subjected to a heat, laser, and / or mechanical bonding process, as an alternative to the inverted bond configuration (as shown, for example, in FIGS. 6A-6C). FIG. 5B and FIG. 5C Further enhancement of bond integrity can be achieved by a mechanical device (e.g., a tape, preferably a marker tape) physically crimped around the outer surface of the heat shrink sleeve. FIG. 7 is a partial longitudinal cross-sectional view of a configuration in which the proximal bond interface region of the balloon 730 (e.g., compliant, semi-compliant, or non-compliant) and the outer surface of the catheter shaft 705 are subjected to a heat bonding (e.g., heat shrink of the return sleeve / sheath 720) and mechanical bonding (e.g., a physically crimped metal marker tape 750) process.

[0055] Prior to placement in the body, the catheter is first "primed" by expelling any residual air from the compliant inflatable balloon. Several different configurations for purging residual air from the inflatable compliant balloon are contemplated. FIG. 8AA possible design is shown in which the vent tube or exhaust tube 875 is a separate component from the catheter shaft 805. The diameter of the vent tube or exhaust tube 875 is chosen to block the passage of inflation fluid (e.g., a contrasted saline solution) and only allow residual air to be purged or expelled. Factors to be considered in choosing the diameter of the vent tube include the pressure in the balloon and the inflation fluid in the balloon (e.g., the ratio of the mixture of contrast and saline). The vent tube or exhaust tube 875 is affixed between the outer surface of the catheter shaft 805 and the balloon 830 (under the proximal or distal bond interface region) using an adhesive 833. The vent outlet or exit 880 of the vent tube 875 is disposed within the cavity defined by the balloon 830 and the outer surface of the catheter shaft 805. Preparation of the balloon 830 (i.e., purging of residual air from the balloon) is achieved by injecting inflation fluid (e.g., a contrasted saline solution) into the balloon 830 via the inflation lumen 890 in the catheter shaft wall, such that the residual air is expelled via the vent tube or exhaust tube 875 without the need to apply a vacuum.

[0056] A separate vent tube or exhaust tube can not be needed at all, but rather the residual air is purged through a vent hole defined in the compliant inflatable balloon. FIG. 8B and FIG. 8C A compliant inflatable balloon 830' is shown affixed to the outer surface of a catheter shaft 805' using a biocompatible adhesive 833 through a non-inverted proximal bond 886 and a distal bond 887 (i.e., bonds formed between the inner surface of the compliant inflatable balloon and the outer surface of the catheter shaft), respectively. In this example, the proximal bond 886 is formed by the adhesive 833 between the outer surface of the catheter shaft 805' and the inner surface of the compliant inflatable balloon 830' at the proximal end of the balloon. The distal bond 887 is formed by the adhesive 833 between the outer surface of the catheter shaft 805' and the inner surface of the compliant inflatable balloon 830' at the distal end of the balloon. FIG. 8B and FIG. 8C In the example shown, the vent or exhaust hole 876 in the compliant inflatable balloon 830' is located proximal and distal to the non-inverted proximal bond 886. Specifically, the location of the vent or exhaust hole 876 is such that as the compliant inflatable balloon 830' continues to inflate, the portion of the compliant inflatable balloon in which the vent hole 876 is defined extends over the non-inverted proximal bond 876 and comes into physical contact with the outer surface of the catheter shaft 805', thereby sealing the vent hole and blocking the passage of inflation fluid through the vent hole. Reference is made to FIG. 8B During preparation of the catheter, injection of inflation fluid through the inflation lumen 890 defined in the outer wall of the catheter shaft 805' causes the compliant inflatable balloon 830' to inflate and the residual air therein to be expelled through the vent hole 876. As the compliant inflatable balloon 830' continues to inflate, the portion of the compliant inflatable balloon in which the vent hole 876 is defined extends over the non-inverted proximal bond 886 and comes into physical contact with the outer surface of the catheter shaft 805', thereby sealing the vent hole and blocking the passage of inflation fluid through the vent hole. FIG. 8CAs shown, continuous inflation causes a portion of the compliant inflatable balloon 830', in which a vent 876 is defined, to extend over the non-inverted proximal junction 886 and physically contact the outer surface of the catheter shaft 805'. The increased pressure within the compliant inflatable balloon causes the balloon to expand radially inward, applying a radially inward force to the extended portion of the balloon, sealing the vent 876 against the outer surface of the catheter shaft, preventing the inflation fluid from passing through the vent, while minimizing dislodgement.

[0057] FIG. 8D and FIG. 8E Another possible catheter configuration is shown for removing residual air through a vent or exhaust port 876' in a compliant inflatable balloon 830", which is secured to the outer surface of the catheter shaft 805" by a biocompatible adhesive 833' via a flipped proximal junction 886' and a distal junction 887' (i.e., a junction formed between the flipped proximal and distal portions of the compliant inflatable balloon and the outer surface of the catheter shaft). FIG. 8D and FIG. 8E In this design, the vent or exhaust port 876' is depicted as the proximal and distal sides of a flipped proximal junction between the outer surfaces of the compliant inflatable balloon 830" and the catheter shaft 805". Specifically, the vent or exhaust port 876' is positioned such that, with continued inflation, the portion of the compliant inflatable balloon 830" defining the exhaust port extends over the flipped proximal junction 876' and physically contacts the outer surface of the catheter shaft 805", thereby sealing the vent and preventing the expansion fluid from passing through it. (See reference...) FIG. 8D During preparation, inflatable fluid is injected through an inflatable cavity 890' defined in the outer wall of the catheter shaft, causing the compliant inflatable balloon 830" to inflate, and residual air is expelled through a vent 876' defined in the balloon. FIG. 8E As shown, continuous inflation causes a portion of the balloon, in which the vent 876' is defined, to extend over the non-inverted proximal junction 886' and physically contact the outer surface of the catheter shaft 805'. The increased pressure within the compliant inflatable balloon exerts a radially inward force on the extended portion of the balloon against the outer surface of the catheter shaft 805', thereby sealing the vent 876' and preventing the inflation fluid from passing through the vent.

[0058] For a given intravascular catheter, different aspects, features, designs, and constructions of the present invention can be combined as needed, with the intended goal of enhancing the integrity and strength of the connection between the balloon and the catheter axis while minimizing the external profile or outer diameter of the assembled catheter.

[0059] Thus, although there have been shown, described and pointed out fundamental novel features of the application as applied to the preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form of the detail of

[0060] Each published patent, pending patent application, publication, journal article, book or any other reference cited herein is each hereby incorporated by reference in its entirety.

Claims

1. A balloon guide catheter comprising: a catheter shaft having a central lumen longitudinally defined therein and an inflation lumen parallel to the central lumen; the catheter shaft having a braid supporting the central lumen and the inflation lumen, the braid being woven over and under the inflation lumen and surrounding the central lumen; a balloon disposed about the braid; and at least one backflow sheath disposed about the balloon; the backflow sheath made of a material capable of backflowing into the braid securing the balloon to the catheter shaft; wherein an exposed portion of the balloon is uncovered by the at least one backflow sheath.

2. The balloon guide catheter of claim 1, wherein the braid is configured in an 8- shape. wherein the proximal backflow sheath and the distal backflow sheath extend radially 360° around a circumference of the catheter shaft and are separated from each other in an axial direction forming a 360° radial gap therebetween, thereby exposing the exposed portion of the balloon; 3. The balloon guide catheter of claim 1, wherein the balloon has a distal edge and an opposite proximal edge; and wherein the balloon guide catheter has two backflow sheaths, including a proximal backflow sheath that overlaps the proximal edge of the balloon and a distal backflow sheath that overlaps the distal edge of the balloon; and wherein in an inflated state, the exposed portion of the balloon protrudes radially outward in the 360° radial gap.

4. The balloon guide catheter of claim 1, wherein the balloon guide catheter has a single backflow sheath extending radially 360° around a circumference of the catheter shaft; the single backflow sheath having an opening coinciding with but smaller in size than a circumference of the balloon, thereby exposing the exposed portion of the balloon through the opening.

5. The balloon guide catheter of claim 1, wherein a distal portion of the inflation lumen coinciding with the at least one backflow sheath is not supported by the braid.

6. The balloon guide catheter of claim 1, wherein a distal portion of the inflation lumen coinciding with the at least one backflow sheath is supported by the braid. ​

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