News Column

Researchers Submit Patent Application, "Guidewire Stop", for Approval

August 28, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors SPENSER, Benjamin (Hof Karmel, IL); ROSENSCHEIN, Uri (M.P. Merkaz, IL); OFIR, Gil (Even Yehuda, IL), filed on September 30, 2013, was made available online on August 14, 2014.

The patent's assignee is Gardia Medical Ltd.

News editors obtained the following quote from the background information supplied by the inventors: "Transcatheter procedures are employed in increasing numbers for opening stenosed or occluded blood vessels. Such minimally invasive procedures have proven to be advantageous compared to traditional surgical procedures, such as open heart surgery. Stenosis in arteries and other blood vessels can be treated by permanently or temporarily introducing a stent into the stenosed region to open the lumen of the vessel.

"However, embolic material may be released into the blood stream during implantation of a stent or another prosthetic device, placing the patient at great risk. Embolic material formed of calcium deposits, intimal debris, pieces of artheromatous plaque and/or thrombi has the potential of migrating downstream and causing distal tissue damage, for example stroke or myocardial infarction (see Topol, E.J. .and Yadov, J.S., 'Recognition of the Importance of Embolization in Athereosclerotic Vascular Disease', Circulation 2000, 101:570). Embolic material which can potentially damage the distal tissue is often released during vascular intervention procedures, such as stenting of an artheromatous region. To alleviate this problem, an embolic filter may be advanced to a site distal to the treatment site to filter and capture undesired embolic material from the blood. The filter is typically formed from a mesh material mounted on an expansion frame adapted to open from a contracted (or collapsed) state to a deployed (or open) state. The filter is typically inserted over or together with a guidewire using a delivery catheter. Following the treatment procedure, the filter is collapsed and removed from the body over the guidewire or together with the guidewire. Additional treatment devices, such as balloons and stents, can be inserted and removed via the same guidewire.

"The filter should be positioned at a location as close as possible distal of the treatment site to ensure that most or all of the embolic debris is trapped by the filter. On the other hand, the guidewire should extend as far as possible into the body lumen to stabilize the treatment site. It is extremely difficult to achieve both these objectives simultaneously when using a built-in filter stop, because accurate placement of the stop relative to the treatment site by fluoroscopic observation is very difficult.

"Therefore, there is a need for a guidewire stop capable of being stopped/locked on a bare guidewire, i.e. a guidewire section devoid of a preformed or fixedly attached stop. There is also a need for an intravascular treatment device capable of being stopped and/or locked on the guidewire at any user-selectable position following deployment of the treatment device in the body lumen."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "The present invention relates to a user-actuatable guidewire stop which can be used to stop and/or lock a medical device on a guidewire advanced through a body lumen. It will be appreciated that this provides the user with a significant advantage, since instead of the medical device being preassembled onto the guidewire as is known in the art, the present invention allows for the user to determine precisely where the medical device is to be placed after the guidewire has been introduced into the body. This is of particular significance, especially when dealing with occluded blood vessels where it is crucial to place an embolic filter at a location where virtually all embolic debris will be trapped. The term 'guidewire' as employed in the present disclosure is intended to refer to any elongated member used to facilitate the advancement of other elements through body lumens. The guidewire may be any standard, non-dedicated guidewire known in the art. There is no need for dedicated guidewire. After the guidewire stop is locked onto the guidewire, the proximal length of the guidewire is available for use for any other purpose or with additional medical devices. While some embodiments of the invention will be described with reference to an embolic filter, it will be appreciated that the guidewire stop of the invention may be useful for any medical device that is designed to be introduced into a body lumen through the use of a guidewire. Thus, the medical device may be adapted for temporary or permanent implantation into any of the body's systems, such as, but not limited to, urological, neurological, or cardiological. It is also appreciated that the state of the art is such that new medical devices are continuously being developed which are designed for implantation into a body lumen via a transcatheter procedure. The guidewire lock of the present invention provides a unique solution for the positioning of such devices with respect to a guidewire. According to one aspect of the invention, an actuatable guidewire stop configured to limit movement of an intravascular device relative to a guidewire includes a coil spring having an inner lumen with a first diameter configured to slideably and rotationally receive the guidewire in an unlocked configuration, and to frictionally engage the guidewire in a locked configuration, wherein in the locked configuration the inner lumen has a second diameter smaller than the first diameter.

"According to another aspect of the invention, an actuatable guidewire stop configured to limit movement of an intravascular device relative to a guidewire includes a tubular member having one or more resilient members formed in a peripheral opening thereof and exerting a radially inward bias force, the tubular member surrounding the guidewire, and a restraining member interposed between the tubular member and the guidewire to maintain the guidewire stop in an unlocked configuration on the guidewire. Upon removal of the restraining member from a space between the tubular member and the guidewire, the resilient member frictionally engages the guidewire and locks the guidewire stop to the guidewire.

"According to yet another aspect of the invention, an intravascular filter device includes a filter frame disposed about a guidewire, a filter membrane operatively coupled to the filter frame, and a coil spring attached to the filter frame. The coil spring has an inner lumen with a first diameter configured to slideably and rotationally receive the guidewire in an unlocked configuration, and frictionally engage the guidewire in a locked configuration, wherein in the locked configuration the inner lumen has a second diameter smaller than the first diameter. In this embodiment, a medical device is connected to the guidewire stop such that locking of the stop onto the guidewire causes the medical device to become locked to the guidewire as well. In other embodiments, the guidewire stop may be independent from the medical device.

"The invention is further directed to a method for locking a guidewire stop onto a guidewire at a desired location along the length of the guidewire, with the steps of advancing a guidewire stop configured as a coil spring having an inner lumen with a first diameter configured to slideably and rotationally receive the guidewire in an unlocked configuration to the desired location, and removing a restraining member which maintains the coil spring in the unlocked configuration, thereby causing the coil spring to frictionally engage the guidewire in a locked configuration and lock the guidewire stop on the guidewire, wherein in the locked configuration the inner lumen has a second diameter smaller than the first diameter.

"Embodiments of the invention may include one or more of the following features. In certain embodiments, the inner lumen of the coil spring may have the first diameter when a longitudinal or radially outward force is applied to the coil spring, and the inner lumen may have a second diameter without an external force being applied to the coil spring.

"In certain embodiments, the guidewire stop may include a restraining member configured to urge the coil spring into the unlocked configuration, wherein the coil spring assumes the locked configuration upon removal of the restraining member. The restraining member may be a tubular member disposed between an inner surface of the coil spring and the guidewire, with an inner diameter of the tubular restraining member being greater than an outside diameter of the section of the guidewire. In other embodiments, the restraining member may be disposed between adjacent turns of the coil spring, wherein the restraining member urges the adjacent turns apart so that the coil spring assumes the unlocked configuration, and wherein the coil spring assumes the locked configuration upon removal of the restraining member. The restraining member may be implemented as a wire or filament.

"In still other embodiments, the restraining member may be disposed along turns of the coil spring and may include at least one protrusion on a turn adapted for engagement with a corresponding recess of an adjacent turn, wherein the protrusion interlocks with the corresponding recess to maintain the coil spring in the unlocked configuration. The recess may have a predetermined undercut angle.

"In other embodiments, the restraining member may include a wire or filament disposed external to and in an axial direction of the coil spring, wherein the wire or filament is affixed to turns of the coil spring by a connection having a rated break point so as to maintain the coil spring in the unlocked configuration, and wherein removal of the wire or filament causes the coil spring to assume the locked configuration on the guidewire. The wire or filament may have a doubled-over configuration with respect to the coil spring and may be affixed to the coil spring by welding spots.

"In certain embodiments, the guidewire stop may include an actuator operatively coupled to a proximal portion of the coil spring for changing the coil spring from the unlocked configuration to the locked configuration. In other embodiments, the actuator may be operatively coupled to a proximal portion of the tubular member for proximally removing the tubular member to change the coil spring from the unlocked configuration to the locked configuration.

"The locking element, for example, the coil spring or tubular member, may be formed from an elastic material or a shape-memory material such as Nitinol.

"The guidewire stop may further include an actuator implemented as a pulling wire, wherein the actuator can be withdrawn together with the restraining member from the body and such that the proximal length of the guidewire is unobstructed and can be used for other purposes.

"These and other features and advantages of the present invention will become more readily appreciated from the detailed description of the invention that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

"The following figures depict certain illustrative embodiments of the invention in which like reference numerals refer to like elements. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way.

"FIGS. 1a and 1b show schematically in a perspective view an exemplary embodiment of a guidewire stop according to the invention, wherein the guidewire stop locking element comprises a single coil spring;

"FIGS. 2a and 2b show schematically in cross section other exemplary embodiments of a guidewire stop according to the invention using a coil spring;

"FIGS. 3a and 3b show schematically another exemplary embodiment of a guidewire stop according to the invention;

"FIG. 3c shows a detail of the guidewire stop of FIGS. 3a and 3b;

"FIGS. 4a and 4b show schematically in a perspective view another exemplary embodiment of a guidewire stop according to the invention;

"FIG. 5a shows schematically in a perspective view another exemplary embodiment of a guidewire stop;

"FIG. 5b shows planar views of the surface of the tubular locking element of FIG. 5a;

"FIG. 5c shows engagement between the guidewire stop of FIG. 5a and the guidewire;

"FIG. 6 shows schematically the guidewire stop of FIGS. 1a with an attached embolic protection filter; and

"FIGS. 7a and 7b show schematically the guidewire stop of FIG. 2a with an attached embolic protection filter."

For additional information on this patent application, see: SPENSER, Benjamin; ROSENSCHEIN, Uri; OFIR, Gil. Guidewire Stop. Filed September 30, 2013 and posted August 14, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=1568&p=32&f=G&l=50&d=PG01&S1=20140807.PD.&OS=PD/20140807&RS=PD/20140807

Keywords for this news article include: Angiology, Blood Vessels, Cardio Device, Intravascular, Medical Devices, Gardia Medical Ltd., Cardiovascular System.

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Source: Politics & Government Week


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