Patent Description:
Various catheters employ different kinds of mechanisms for maneuvering the catheter distal end. For example, <CIT> describes a catheter to be used without a guidewire. The catheter includes a support wire shaft formed of metal, a balloon mounted on a distal portion of the catheter, and an inflation shaft for inflating the balloon, wherein a core wire may be interchangeably inserted into the support wire shaft when the catheter is within a human body to change the stiffness and improve control thereof.

As another example, <CIT> describes a medical device for treating a defective heart valve. The medical device comprises a distal anchoring member for disposing in a blood vessel, a proximal anchoring member for disposing in or at an entrance of the blood vessel, and a telescoping assembly coupling at a first end to the distal anchoring member and at a second end to the proximal anchoring member. The telescoping assembly is deployable into the blood vessel. The telescoping assembly reduces a distance between the distal anchoring member and the proximal anchoring member, wherein the telescoping assembly comprises of at least two members capable of sliding into each other giving the telescoping assembly adjustable lengths.

<CIT> describes a circumferential ablation catheter having a moveable tube that extends through a lumen of an inner support member and through the catheter body. The moveable tube is longitudinally moveable relative to the inner support member and catheter body and has a distal end that extends beyond the distal end of the inner support member. An inflatable balloon is provided generally in surrounding relation to the circumferential ablation element. The inflatable balloon has a proximal end attached, directly or indirectly, to the distal end of the catheter body and a distal end attached, directly or indirectly, to a portion of the moveable tube that extends beyond the distal end of the inner support member. Longitudinal movement of the moveable tube relative to the catheter body and inner support member causes movement of the distal end of the balloon relative to the proximal end of the balloon to thereby change the length and shape of the expanded balloon. First and second off centered puller-wires are provided for deflection of the catheter body.

<CIT> describes a steerable catheter, which is adapted to be inserted into a body lumen. The catheter comprises a symmetrical cylindrical control handle, an elongate tubular catheter body, and a flexible catheter tip having a lumen offset from the axis of the catheter tip. The control handle comprises a housing having a piston chamber at its distal end. A piston is mounted in the piston chamber and is afforded lengthwise movement. The proximal end of the catheter body is fixedly attached to the distal end of the piston. A puller-wire made of nickel-titanium alloy having shape memory is attached to the housing and extends through the piston, through and coaxial with the catheter body and into the offset lumen of the catheter tip where it is attached to the wall of the catheter tip. Lengthwise movement of the piston relative to the housing results in deflection of the catheter tip.

<CIT> describes a deflectable catheter whose puller member connections are accomplished with minimal, if any, surface deformation which could otherwise accelerate breakage under tension. The catheter includes a molded member that encases an end of a puller member to enable connection of the end to a fixed or movable structure in the control handle without significant surface deformation in the puller member. The molded member is of a thermoplastic material that encases a preformed end of the puller member, which may be a puller-wire or a high modulus fiber material. The molded member may be configured as desired, for example, as a screw that is fastened to a structure in the control handle. Alternatively, the preformed end of the puller member, for example, a puller-wire, can be directly connected to and jointly encased in the molded member with another preformed end of a second puller member, for example, a high modulus fiber material. Such a connected puller member whose distal portion is the puller-wire and whose proximal portion is the high modulus fiber material can be well suited for control handle that employs pulleys for increased throw capacity.

<CIT> describes methods and devices for biasing a balloon catheter. A described medical device includes a catheter shaft and a balloon assembly coupled to a distal region of the catheter shaft. The balloon assembly defines a chamber configured to be inflated and deflated using a fluid supplied from the catheter shaft. A biasing member may be positioned in the chamber of the balloon assembly and may be configured to bias the balloon assembly to a longitudinally extended state without obstructing an exhaust lumen of the catheter shaft. The biasing member may be a spring or a coiled portion of a fluid supply line.

The present invention is defined in claims <NUM> and <NUM>, and further defined in the dependent claims <NUM>-<NUM>.

An embodiment of the present invention provides a medical instrument including a shaft, a distal-end assembly and a puller-wire. The shaft is configured for insertion into a body of a patient. The distal-end assembly, which is coupled to the shaft, includes a telescopic assembly, configured to elongate so as to collapse the distal-end assembly, and to compress so as to expand the distal-end assembly. The distal-end assembly further includes an elastic element, coupled to self-elongate and thus elongate the telescopic assembly. The distal-end assembly also includes an inflatable balloon, which is coupled to the telescopic assembly and is configured to collapse by the telescopic assembly elongating, and to expand by the telescopic assembly compressing. The puller-wire runs through the shaft and is connected to a distal end of the telescopic assembly, and is configured, when pulled, to compress the telescopic assembly.

In some embodiments, the inflatable balloon includes a distal end connected to a distal section of the telescopic assembly, and a proximal end connected to a proximal section of the telescopic assembly. In some embodiments, the elastic element includes one or more springs. In an embodiment, the elastic element includes one or more elastic splines. In another embodiment, the medical instrument further includes a handle, which is located outside the body and is configured to pull the puller-wire.

There is also provided, in accordance with an embodiment of the present invention, a method, including fitting at a distal end of a shaft a distal-end assembly, which includes a telescopic assembly, configured to elongate so as to collapse the distal-end assembly, and to compress so as to expand the distal-end assembly, an elastic element, coupled to self-elongate and thus elongate the telescopic assembly, and wherein the distal-end assembly further includes an inflatable balloon, which is coupled to the telescopic assembly and is configured to collapse by the telescopic assembly elongating, and to expand by the telescopic assembly compressing. The method further includes running a puller-wire through the shaft and connecting the puller-wire to a distal end of the telescopic assembly such that pulling the puller-wire compresses the telescopic assembly.

Embodiments of the present invention that are described hereinafter provide improved methods and mechanisms for expanding and collapsing a balloon at a distal end of a medical instrument, e.g., a cardiac ablation catheter. The medical instrument comprises a telescopic assembly fitted at a distal end of a shaft, an elastic element coupled to retain the telescopic assembly in an elongated state, a puller-wire connected to compress the telescopic assembly under control of a physician. An inflatable balloon is coupled to be retained in an elongated, collapsed state by the telescopic assembly being in an elongated state, and to be prepared for inflation and expand due to the telescopic assembly being compressed.

The puller-wire may be thin and highly flexible (e.g., as there is no need for the wire to be stiff as for example pusher-wires need to). The puller-wire is connected to the telescopic assembly such that pulling the puller-wire compresses the telescopic assembly. The elastic element, such as a spring, is coupled to the telescopic assembly such that when it self-elongates it elongates the telescopic assembly. In some embodiments, an inflatable balloon is coupled to the telescopic assembly such that the compression of the telescopic assembly facilitates the inflation of the balloon, while elongating the telescopic assembly assists collapsing the balloon.

The compression and extension of the telescopic assembly may be realized by causing one or more sections of the telescopic assembly to telescopically slide into one another. Various realizations and variations of a telescopic motion that compresses the telescopic assembly by pulling a puller-wire, and elongating the telescopic assembly by a self-elongating elastic element applying an opposing force, are possible.

As an example, the telescopic assembly may be compressed by pulling proximally a distal section, or by pulling distally a proximal section, or by a combination thereof, depending on detailed alternative designs of elements such as transmission mechanisms of the puller-wire and arrangements of one or more opposing elastic elements. Hence, embodiments that are provided hereinafter serve to exemplify several possible realizations, whereas potentially many more may occur to persons skilled in the art.

In various embodiment, any relevant implementation of (a) a telescopic assembly (b) an elastic element, and (c) a puller-wire, which together enable the elongation and compression of the telescopic assembly as describes herein. It is therefore to be understood that certain mechanical parts and/or principles may be included or omitted in possible realizations, and that the principles provided by the disclosed embodiments can be implemented using numerous other possible realizations.

In some embodiments, the telescopic assembly includes a movable distal section and a proximal section fixed to a shaft. The telescopic motion between the distal section and the fixed proximal section either compresses or elongates the overall length of the two-section telescopic assembly.

In some embodiments an inflated balloon is coupled to the telescopic assembly. A distal end of the inflated balloon is coupled to the distal end of the distal section, while a proximal end of the balloon is coupled to the proximal end of the proximal section. With this configuration, motion of the distal section in the distal direction, which elongates the telescopic assembly, elongates the balloon so as to assist its collapsing by evacuating the saline from the interior of the balloon. By the same token, motion of the distal section in the proximal direction, which compresses the telescopic assembly, contracts the balloon in a longitudinal direction (i.e., parallel to the telescopic motion) and by doing so allows the balloon to be inflated.

In some embodiments, the elastic element retains the telescopic assembly in a normally-elongated state. A puller-wire running through the shaft is connected to the distal section. When the puller-wire is pulled in the proximal direction by the physician, the puller-wire pulls the distal section proximally so as to compress the telescopic assembly. The compression of the telescopic assembly contracts the balloon from its elongated state and thus expands the balloon to make room for inflating the balloon (e.g., by filling the balloon with saline solution), in preparation of performing some diagnostics and/or a therapy.

In some embodiments, the elastic element comprises one or more self-elongating splines or springs, which elongate the telescopic assembly. In some embodiments, the one or more splines or springs are fixed at their proximal ends to the proximal section and are fixed at their distal ends to the distal section. The splines or springs have a preformed shape that is an elongated one. As a result of their induced inherent tendency to self-elongate, the splines or springs force the distal section of the telescopic assembly to move distally so as to elongate the telescopic assembly to its maximal designed length. In order for the elongation to occur, the pulling force by which the puller-wire is pulled or held should be weaker than the force that the splines or springs exert on the distal section. The inflatable balloon coupled to the telescopic assembly will be correspondingly elongated (and thus the telescopic assembly assists in bringing the balloon to a collapsed state).

Once the physician decides to retract the balloon assembly, he or she releases some or all of the pulling tension in the puller-wire. The splines then self-elongate and push the distal section distally to assist the balloon in collapsing. When the balloon is collapsed and fully elongated, the physician can safely retract the balloon assembly into the catheter sheath and maneuver the catheter out of the patient's body.

When using the disclosed configurations, the puller-wire may be very thin and highly flexible. This feature is in contrast to solutions based on pusher-wire, in which the pusher-wire must be rigid and therefore thick and less flexible. As such, the disclosed techniques, enable highly flexible catheter designs capable of performing sharp turns. A highly flexible balloon catheter using the disclosed telescopic assembly assisted by a puller-wire may thus particularly maneuverable via sharp deflections of blood vessels, and by so overcoming an obstacle that may otherwise hinder catheterization. Moreover, the overall catheter diameter may be reduced.

<FIG> is a schematic, pictorial illustration of a balloon catheterization system <NUM> comprising a telescopic balloon assembly <NUM>, in accordance with an embodiment of the present invention. System <NUM> comprises a catheter <NUM>, wherein, as an inset <NUM> shows, a distal end of shaft <NUM> of the catheter is inserted through a sheath <NUM> into a heart <NUM> of a patient <NUM> lying on a table <NUM>. The proximal end of catheter <NUM> is connected to a control console <NUM>. In the embodiment described herein, catheter <NUM> may be used for any suitable therapeutic and/or diagnostic purposes, such as electrical sensing, balloon angioplasty and ablation of tissue in heart <NUM>, to name just few possible medical usages of inflatable balloon catheters.

Physician <NUM> navigates the distal end of shaft <NUM> to a target location in heart <NUM> by manipulating shaft <NUM> using a manipulator <NUM> near the proximal end of the catheter and/or deflection from the sheath <NUM>. During the insertion of shaft <NUM>, telescopic balloon assembly <NUM> is maintained in a collapsed configuration by sheath <NUM>. By containing telescopic balloon assembly <NUM> in an elongated (and thus collapsed) configuration, sheath <NUM> also serves to minimize vascular trauma along the way to target location.

Control console <NUM> comprises a processor <NUM>, typically a general-purpose computer, with suitable front end and interface circuits <NUM> for receiving signals from catheter <NUM>, as well as for applying treatment via catheter <NUM> in heart <NUM> and for controlling the other components of system <NUM>. Processor <NUM> typically comprises a general-purpose computer, which is programmed in software to carry out the functions described herein. The software may be downloaded to the computer in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and/or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory.

The example configuration shown in <FIG> is chosen purely for the sake of conceptual clarity. The disclosed techniques may similarly be applied using other system components and settings. For example, system <NUM> may comprise other components and perform non-cardiac treatments.

<FIG> are schematic, pictorial illustrations of telescopic balloon assembly <NUM> in elongated and compressed states, in accordance with an embodiment of the present invention.

<FIG> show telescopic balloon assembly <NUM> in an elongated state fitted at the distal end of shaft <NUM>. As seen, a proximal section <NUM> and a distal section <NUM> are assembled into a two-part structure of telescopic assembly <NUM>. In some embodiments proximal section <NUM> and a distal section <NUM> comprise a tube, but many other, non-cylindrical cross-sections, may be used. Proximal section <NUM> is coupled to shaft <NUM>, while distal section <NUM> can move telescopically inside proximal section <NUM>, i.e., its motion is either proximally or distally along a direction parallel to shaft <NUM>. As seen, balloon <NUM> is coupled at its distal end to distal section <NUM> by an anchor <NUM> and is coupled at its proximal end to proximal section <NUM> by an anchor <NUM>.

The elongation of telescopic balloon assembly <NUM> is caused by splines <NUM> self-elongating towards their preshaped lengths. As seen, inflatable balloon <NUM> is retained in an elongated state by telescopic assembly <NUM> being in an elongated state.

A puller-wire <NUM> runs through shaft <NUM> and within the two-part telescopic assembly and is connected to distal section <NUM> at a distal edge of section <NUM>. In an embodiment, puller-wire <NUM> is operated (e.g., pulled or relaxed) from a handle of catheter <NUM>. When physician <NUM> is ready to inflate balloon <NUM>, the physician command compressing telescopic balloon assembly <NUM>, which is performed by pulling of puller-wire <NUM>. As seen in <FIG>, the two-part telescopic assembly <NUM> is compressed by pulling puller-wire <NUM> proximally forcefully enough for distal section <NUM> to force one or more elastic splines <NUM> to bend. In an embodiment, a stopper <NUM> limits the motion of distal section <NUM> to the required length. As seen in <FIG>, balloon <NUM> is longitudinally contracted and so as to being ready to be inflated, for example, by pressurized saline solution.

When the physician command the elongation of telescopic balloon assembly <NUM>, the force at which puller-wire <NUM> is pulled proximally is reduced sufficiently by a pulling apparatus (not described) to let splines <NUM> to self-elongate. Correspondingly, inflatable balloon <NUM> is elongated, making the balloon ready for retraction into sheath <NUM>.

The example illustrations shown in <FIG> are chosen purely for the sake of conceptual clarity. Elastic splines <NUM> may have different shapes and may be made from various materials. Other telescopic arrangements are possible. For example, distal section <NUM> may encompass proximal section <NUM> from the outside. As another example, the telescopic assembly may comprise more than two sections. Stopper <NUM> is brought by way of example only, the limit over distal section <NUM> motion may be realized, among other options, electronically, by using for example, a proximity sensor. As another example, the limit over of the motion of distal section <NUM> can be realized by setting the pulling force (transmitted by puller-wire <NUM>) such it is balanced by the resistance elastic splines <NUM> at a given bend of splines <NUM>, which brings the telescopic assembly into static equilibrium at a given pre-designed length.

<FIG> are schematic, pictorial illustrations of telescopic balloon assembly <NUM> in elongated and compressed states, in accordance with another embodiment of the present invention.

In the embodiment exemplified by <FIG>, a spiral (helical) spring <NUM>, which is enclosed in proximal section <NUM> and pressed against distal section <NUM>, is used for pushing distal section <NUM> to elongate telescopic balloon assembly <NUM>. As seen in <FIG>, pulling puller-wire <NUM> compresses telescopic balloon assembly <NUM> and by so longitudinally contracts balloon <NUM> to enable the inflation of balloon <NUM>. The example illustration shown in <FIG> is brought mainly to demonstrate that various designs are possible for achieving the same end result elaborated above of compressing and elongating telescopic balloon assembly <NUM>. Additional designs with vast options for of elements and materials may occur to persons skill in the art.

<FIG> is a flow-chart that schematically illustrates a method for telescopically compressing and elongating telescopic balloon assembly <NUM> using puller-wire <NUM>, the telescopic balloon assembly <NUM> being in accordance with an embodiment of the present invention.

The process may begin with physician <NUM> advancing telescopic balloon assembly <NUM> while being held collapsed in sheath <NUM>, at a balloon advancement step <NUM>. Physician <NUM> may advance sheath <NUM> through sharp deflections of blood vessels, as such pose less of an obstacle to the highly flexible shaft <NUM> of catheter <NUM> (a flexibility attributed largely to the high flexibility of puller-wire <NUM> within shaft <NUM>).

After physician <NUM> navigated telescopic balloon assembly <NUM> to its target location in heart <NUM>, physician <NUM> retracts sheath <NUM> or advances balloon assembly <NUM>, exposing the elongated telescopic balloon assembly <NUM>. Physician <NUM> then commands the pulling of puller-wire <NUM>, so as to telescopically compress telescopic balloon assembly <NUM> and by so longitudinally contracting balloon <NUM> to enable inflating balloon <NUM>, at a pulling step <NUM>. Physician <NUM> inflates balloon <NUM>, at an inflation step <NUM>, and performs the required clinical procedure, at a clinical step <NUM>.

Once physician <NUM> wishes to deflate balloon <NUM>, physician <NUM> commands then a relaxation of tension which puller-wire <NUM> transmits, allowing splines <NUM> to self-elongate so as to telescopically elongate telescopic balloon assembly <NUM> and correspondingly elongate balloon <NUM>, at an elongation step <NUM>. The elongation of balloon <NUM> assists deflating and collapsing balloon <NUM>. The physician can then safely retract the elongated and collapsed telescopic balloon assembly <NUM> back into sheath <NUM>, in retraction step <NUM>.

The example flow chart shown in <FIG> is chosen purely for the sake of conceptual clarity. The operation method of telescopic balloon assembly <NUM> is to serve only as an illustrative example of a puller-wire method disclosed. For example, physician <NUM> may perform additional steps prior, during or after clinical step <NUM>.

Although the embodiments described herein mainly address cardiac applications, the methods and systems described herein can also be used in other applications, such as otolaryngology or neurology procedures.

Claim 1:
A medical instrument, comprising:
a shaft (<NUM>) for insertion into a body of a patient;
a distal-end assembly (<NUM>), which is coupled to the shaft (<NUM>) and comprises:
a telescopic assembly (<NUM>, <NUM>), configured to elongate so as to collapse the distal-end assembly, and to compress so as to expand the distal-end assembly;
an elastic element (<NUM>), coupled to self-elongate and thus elongate the telescopic assembly; and
an inflatable balloon (<NUM>), which is coupled to the telescopic assembly (<NUM>, <NUM>) and is configured to collapse by the telescopic assembly elongating, and to expand by the telescopic assembly compressing; and
a puller-wire (<NUM>), which runs through the shaft and is connected to a distal end of the telescopic assembly (<NUM>, <NUM>), and which is configured, when pulled, to compress the telescopic assembly (<NUM>, <NUM>).