News Column

"Balloon Catheter" in Patent Application Approval Process

May 8, 2014

By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors Miller, John (Redwood City, CA); Dieck, Martin (Cupertino, CA); Aboytes, Maria (East Palo Alto, CA); Pierce, Ryan K. (Mountain View, CA), filed on October 9, 2013, was made available online on April 24, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application is assigned to Concentric Medical, Inc.

The following quote was obtained by the news editors from the background information supplied by the inventors: "This invention is a medical device. In particular it is a balloon catheter having at least two lumens. One of the lumens is a large working lumen. The inventive catheter is especially useful as a guide catheter or a micro catheter and may be used in a variety of therapeutic and diagnostic procedures variously in the neuro-, peripheral, and coronary vasculature. In particular, it has value in treating neurovascular embolic strokes in combination with other devices which are delivered to the stroke site through the working lumen. The remainder of the lumens typically are used to inflate and to deflate the balloon. It is highly preferable that the balloon or inflatable member be situated in a recess in the outer wall of the inventive catheter. The distal end of the catheter past the balloon may be tapered. The inventive device has a very low profile as compared to other catheters of the balloon catheter genre. It may include other features such as variable stiffness along the axis of the device and anti-kinking components. The balloon may be compliant in nature.

"When intended for use in treating embolic stroke, the inventive catheter may be a component of a kit including a clot retriever. Further, amongst other procedures, the invention includes methods of temporarily blocking a vascular lumen, of removing coronary, neurovascular, or peripheral emboli. Other procedures, where diagnosis or treatment is needed in a vascular space and a large working lumen is desired, are suitable procedures for the inventive balloon catheter.

"This invention relates generally to medical balloon catheters, their structures, and methods of using them. In particular, the present invention relates to the construction of both large and small diameter, typically braid-reinforced balloon catheters having controlled flexibility, a soft distal tip and a typically elastomeric balloon near the distal tip for the partial or total occlusion of a vessel. This catheter has a comparatively large working lumen and carries at least one inflation lumen independent of the working lumen. The inventive catheter may be used for a wide variety of medical applications, such as interventional cardiological, peripheral, or neuroradiology procedures, but is particularly useful in support of intercranial selective catheterization.

"Medical catheters are used for a variety of purposes, including interventional therapy, drug delivery, diagnosis, perfusion, and the like. Catheters for each of these purposes may be introduced to target sites within a patient's body by guiding the catheter through the vascular system, and a wide variety of specific catheter designs have been proposed for different uses.

"Examples of the present invention are large lumen balloon catheters used in supporting procedures that, in turn, use small diameter tubular access catheters. Such procedures include diagnostic and interventional neurological techniques, such as the imaging and treatment of aneurysms, tumors, arteriovenous malformations, fistulas, and the like. Practical treatment of embolic stroke is novel.

"The neurological vasculature places a number of requirements on the small catheters to be used there. The catheters should be quite fine. The blood vessels in the brain are frequently as small as several millimeters, or less, requiring that the intervening catheters have an outside diameter as small as one French (0.33 mm). In addition to small size, the brain vasculature is highly tortuous, requiring neurological catheters to be very flexible, particularly at the distal ends, to pass through the regions of tortuosity. The blood vessels of the brain are quite fragile, so it is desirable that the catheter have a soft, non-traumatic exterior to prevent injury.

"Similarly, catheters used in supporting these procedures have similar requirements. Balloon catheters used in directing the smaller neurovascular catheters desirably have thin walls and are easily maneuverable. The central, or 'working' lumen desirably is quite large to assist in effecting the procedures.

"Although the peripheral and coronary vasculature is typically not as small nor as tortuous as is the neurovasculature, the advances in neurovascular catheter technology is quite applicable in advancing these procedures as well.

"Typical of balloon guide catheters are those shown in U.S. Pat. No. 5,628,754, to Kranys; U.S. Pat. No. 5,833,659, to Kranys; U.S. Pat. No. 5,836,912, to Kusleika; U.S. Pat. No. 5,681,336, to Clement et al; and U.S. Pat. Nos. 5,759,173 and 5,728,063, both to Preissman et al. None of these patents show the structure disclosed herein."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "This invention involves a balloon catheter. The balloon is situated distally on the catheter body. The inventive catheter typically has a large working lumen extending from one end of the catheter to the other. The outer surface of the balloon may have a substantially constant outside diameter. The balloon is situated in a recessed region at the distal end often just proximal of a soft, tapered tip.

"An example of the inventive balloon catheter is made up of an outer or first elongate tubular member having an outer surface, a proximal end, and a distal end. In this variation the first elongate member has the noted substantially constant diameter and the radially recessed region near the distal end containing the balloon. As an example, the balloon may be a longitudinally stretched inflatable member situated within the radially recessed region. The balloon, may be compliant, is connected to at least one fluid supply lumen that is independent of the working lumen. When compliant, the balloon may be stretched longitudinally at least 10%, perhaps 15% or more, upon attachment to the first elongate tubular member. Exemplary materials for the balloon include natural and synthetic rubbers and silicone materials. Chlorinated Neoprene materials such as Chronoprene or C-Plex are suitable balloon materials.

"The balloon itself may be coated with various materials. For instance, the balloon may be coated with a hydrophilic material. One exemplified hydrophilic coating comprises sodium hyaluronic salt. Similarly, coatings based upon polyvinylprolidone (PVP) or polyurethane may be used. Hydrophilic coating materials such as SLIP-COAT, GLIDE-COAT, GRAFT-COAT by STS Biopolymers Inc., SLIPSKIN by MCTec, HYDRO-SLIP C by CT Biomaterials, a division of Cardio Tech International, ARMORGLIDE from ARROW, and the like are suitable.

"In this variation, a second (or inner) elongate tubular member that is substantially concentric with the first elongate tubular member forms an annular lumen between the two for supplying fluid to the balloon. The interior surface of the inner elongate member forms the working lumen.

"The first elongate member joins the second elongate tubular member distal of the balloon.

"The second elongate tubular member generally contains a stiffener member situated in its wall to provide kink resistance and torqueability to the balloon catheter. The stiffener member may be a coil or a braid. The inner member may have varying stiffness between its distal and its proximal end, being formed of segments of polymers having different stiffnesses.

"In other variations of the inventive catheter, the first elongate tubular member has a wall that contains one or more fluid supply lumens for inflating the balloon. Those fluid supply lumens may be within tubing, perhaps spirally embedded in the wall or perhaps a woven braid embedded in the wall. The tubing may be square tubing or round tubing or other convenient shape. The tubing may be polymeric or metallic. The metallic tubing may be a superelastic alloy.

"Ancillary features, e.g., radio-opaque marker bands distal of said inflatable member and fluid fittings, are included.

"The second elongate tubular member may include a lubricious, polymeric tubular inner-most tubing member.

"Another subgeneric variation of the inventive catheter has the fluid supply lumens in the wall of the first tubing member. The lumens may be integral with the wall, e.g., passageways integral in or grooved into the first elongate tubular member and closed by an inner lubricious tubing.

"Although the inventive balloon catheter desirably is used as a guide catheter, it may be designed with a flexibility, length, and diameter appropriate for use as a neurovascular, coronary, or peripheral microcatheter.

"The outer member may be formed of polymeric tubing, but may also include a braid or helically wound coil of wire or ribbon.

"An independent portion of the invention includes a braided tubular structure made up of a plurality of component tubular members each having longitudinal lumens, woven radially in and out to form the substantially tubular braided structure, potentially ending at one end in a plenum. The braided tubular structure may be made up of, e.g., polymeric tubing, metallic tubing (perhaps a superelastic alloy of nickel and titanium, such as nitinol). The braided tubular structure may also include at least one polymeric tubular member on its exterior. The size and shape may be useful in devices suitable for introduction into a human blood vessel.

"Although the inventive balloon catheters may be independently chosen for use with any number of procedures, they may also be incorporated into one or more kits tailored for a specific procedure. For instance, a kit might contain, e.g., a dilator having a lumen extending from a proximal end of the dilator to a distal end of the dilator and having a diameter closely fitting within the balloon catheter lumen; a microcatheter having a microcatheter lumen; a guidewire slideable within either the dilator lumen or the microcatheter lumen; and a clot retrieval device adapted to fit within the lumen of the balloon catheter with a retrieved clot. The microcatheter may be a balloon catheter.

"Another desirable kit includes a microballoon catheter having a flexibility, length, and diameter appropriate for a neurovascular microcatheter, a guidewire slideable within the microcatheter lumen, and a clot retrieval device adapted to fit within the lumen of the balloon catheter and extend to a radially expanded state.

"The catheter may be used in a variety of procedures such as removing an embolus from a vascular lumen, e.g., in sites as varied as the middle cerebral artery, the periphery, or the coronary vessels, by the steps of: introducing the balloon catheter to a position proximal said embolus, extending a microcatheter from the distal end of said balloon catheter to penetrate the embolus, extending a clot removal device through the embolus past the microcatheter, inflating the balloon of the balloon catheter to temporarily occlude the vascular lumen, withdrawing the microcatheter, the clot removal device, and the embolus into or adjacent the balloon catheter, deflating the balloon, and withdrawing the retriever and embolus into the balloon catheter. In any of these procedures, the microcatheter may be a balloon microcatheter.

"Other clot removal devices may be used in combination with the inventive catheter.

"The inventive catheter may be used for treating a site in a vascular lumen or performing a diagnostic step in a vascular lumen by the steps of introducing the balloon catheter to a position in the lumen, inflating the balloon of said balloon catheter to temporarily occlude the vascular lumen, treating the site or performing a diagnostic step at the site, deflating the balloon, and withdrawing the balloon catheter.

"Another variation of the present invention is a balloon catheter having an inflatable member mounted to both the inner and outer tubular members. In this variation, a proximal portion of the inflatable member is mounted to a radially recessed region of the outer tubular member. A distal portion of the inflatable member or balloon is mounted to the inner tubular member at a location distal to the distal end of the outer tubular member. The balloon may mounted to the tubular members such that, when deflated, the balloon is in a stretched state. Also, the outer and inner tubular members may be fixed together using glue to prevent 'telescoping' movements between the members.

"Another variation of the present invention includes a balloon catheter having an inner tubular member comprising a braided reinforcement layer extending from the proximal end to a point proximal the distal end of the inner tubular member. The braided reinforcement member, in this variation, terminates at a point 3 cm or less from said distal end of the inner tubular member. This inner tubular member is useful in the variations described above that do not exclude such a configuration.

"The balloon or inflatable member in any of these variations may have a spherical shape when inflated or maybe a non-spherical when inflated.


"FIG. 1 shows a kit of devices including the inventive balloon catheter (used as a guide catheter) suitable for treating embolic stroke.

"FIG. 2A shows, in partial longitudinal cross section, a variation of the inventive catheter. FIG. 2B shows in cross section, the variation found in FIG. 2A.

"FIGS. 3A-3E show, in partial longitudinal cross-section, details of the wall construction of the outer tubular member.

"FIGS. 4A and 4B show, in partial longitudinal cross section, details of the inflatable member construction.

"FIG. 4C shows, in partial longitudinal cross-section, another variation of the distal section of a catheter in accordance with the present invention.

"FIG. 4D shows, in another partial longitudinal cross-section, yet another variation of the distal section of a catheter in accordance with the present invention. FIG. 4E shows in cross section, the variation found in FIG. 4D.

"FIGS. 5, 6, and 7 show variations of the interior tubular member.

"FIG. 8A shows a partial longitudinal cross section of a desirable variation using woven tubing as the inflation lumen for the balloon. FIG. 8B shows a cross section of the catheter shaft shown in FIG. 8A.

"FIG. 9 shows a further variation of a catheter shaft having one or more rectangular tubes as delivery lumen for the inflatable balloon.

"FIGS. 10, 11, 12, 13, and 14 show integrated variations of catheter shafts suitable for use in the inventive balloon catheter assembly.

"FIG. 15 shows one procedure for using the inventive catheter and the allied kit for treatment of an embolism in an artery."

URL and more information on this patent application, see: Miller, John; Dieck, Martin; Aboytes, Maria; Pierce, Ryan K. Balloon Catheter. Filed October 9, 2013 and posted April 24, 2014. Patent URL:

Keywords for this news article include: Stroke, Surgery, Legal Issues, Therapeutics, Cardio Device, Guide Catheter, Medical Devices, Balloon Catheter, Surgical Technology.

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Source: Politics & Government Week

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