Patent Description:
The disclosure relates to the field of medical devices, and in particular relates to the field of catheters.

In some procedures, there is a problem withdrawing a catheter that has a wire extended out of a side port of the catheter when the wire is pushed into the side of the catheter distal of the side port such that there is not enough space (or too much friction between the wire and catheter) to retract the catheter while maintaining wire position. The problem may be addressed by a catheter disclosed herein which is sufficiently radially collapsible distal of the side port to yield to the wire such that there is enough space to withdraw the catheter without altering the position of the wire. Such a catheter is described in claim <NUM>. Claims <NUM>-<NUM> describe embodiments of the invention.

In one broad aspect, embodiments of the present invention include a catheter comprising a catheter body, the catheter body defining at least a primary catheter lumen and at least one side-port in communication with the primary catheter lumen, a distal portion of the catheter extending distal to the at least one side-port, the side-port being configured to allow travel of a device (a wire or other component) therethrough, wherein the distal portion of the catheter is radially collapsible.

As a feature of this broad aspect, the distal portion of the catheter body is operable to collapse inwardly into the primary catheter lumen and thereby temporarily adopt a reduced profile in a collapsed configuration when force is applied to an outer surface of the distal portion of the catheter body.

As a feature of other embodiments of this broad aspect, the distal portion of the catheter body is operable to collapse inwardly into the primary catheter lumen, and thereby temporarily adopt a reduced profile in a collapsed configuration, when a controlled force is applied to the distal portion of the catheter body.

In order that the invention may be readily understood, embodiments of the invention are illustrated by way of examples in the accompanying drawings, in which:.

A surgical procedure, such as, for example, a percutaneous transluminal angioplasty (PTA) of a challenging occlusion, may include a guide-wire being advanced and taking a sub-intimal path, intentionally or unintentionally. A physician has the option of using a re-entry catheter with a side-port to gain access to the true lumen (i.e. the lumen of the vessel containing the occlusion) distal of the occlusion. There is more than one way to gain access to the true lumen using a side-port of a re-entry catheter. For example, the catheter could be a deflecting catheter that deflects an advancing wire, or alternatively, a directable/steerable wire (e.g. an angled guide-wire) could be directed through a passive side-port (i.e. the side-port of a non-deflecting catheter). The advancing wire may have a sharp tip for cutting, or alternatively, it may have an atraumatic tip with an electrode for delivering energy for puncturing.

Once access to a true lumen has been gained, a wire advanced into the true lumen may be used as a rail to advance devices, such as balloons or stents, into the true lumen. Prior to using a wire that has been advanced from the sub-intimal space into the true lumen as a rail, the re-entry catheter is typically withdrawn while avoiding pulling the wire back into the sub-intimal space.

Withdrawing a catheter that has a wire extended out of a side-port of the catheter poses a challenge when the wire and catheter are contained in a region of tissue, lumen or other structure where movement is restricted. For example, when withdrawing a catheter having a wire extended through a side-port thereof, while retaining a position of the wire in a tissue, a portion of the catheter distal to the side-port is retracted alongside the wire. In some such situations, unhindered retraction of the catheter is prevented due to the structure through which the catheter has been positioned, i.e. there are limited, if any, gaps between the outer surface of the catheter and the surrounding structure. Under such circumstances, as the catheter is retracted, the wire extending through the side-port is forced against the outer surface of the portion of the catheter distal of the side-port whereby friction between the wire and catheter may cause the catheter to pull the wire out of position.

Challenges such as described above may occur, for example, in a lumen having a diameter less than the total of the catheter outer diameter and the wire outer diameter, whereby there is insufficient space to allow for unimpeded or unhindered retraction of the catheter alongside the wire. In one specific example, a re-entry catheter has a profile that is too large for it to be withdrawn through a 6F introducer while maintaining the wire position. Alternatively, such challenges may occur when the re-entry catheter is positioned sub-intimally through a vessel wall.

As will be further described hereinbelow, the present inventors have conceived of and reduced to practice an embodiment of a catheter configured to be sufficiently radially collapsible or deformable distal of the side-port in order to yield to forces applied thereto, for example by a wire positioned alongside, to thereby adopt a reduced profile distal of the side-port. Such an embodiment allows for reduced friction between the wire and catheter, which in turn enables withdrawal or retraction of the catheter while avoiding significantly altering the position of the wire.

In some such is examples which are not part of the invention, the radially collapsible or deformable portion of the disclosed catheter is able to temporarily adopt a lower or reduced profile without any direct user control of collapsibility. In such embodiments, the radially collapsible portion of the catheter distal of the side-port may be described as having passive collapsibility or passive radial flexibility.

In the invention, the distal portion of the catheter body is operable to collapse inwardly into the primary catheter lumen, and thereby temporarily adopt a reduced profile in a collapsed configuration, when a controlled force (i.e. a force controlled by a user) is applied to the distal portion of the catheter body. In such embodiments, the radially collapsible portion of the catheter distal of the side-port may be described as having controlled or active collapsibility.

Typically, embodiments of the disclosed catheter are used in a sheath and the sheath defines the lumen containing the catheter. In alternative applications, embodiments of the catheter are used without a sheath, or advanced forward of a sheath whereby an anatomical feature, such as a vessel wall, defines the structure containing the catheter.

An exemplary embodiment is illustrated in <FIG>, which shows a cross-sectional view of a sheath <NUM> containing a catheter body <NUM> and a wire <NUM> that has previously been advanced through a side-port of the catheter. When a wire has been advanced through the side-port of a catheter defining a lumen, the portion of the catheter lumen distal to the side-port is understood to be "empty" i.e. the wire is absent from that portion of the catheter. <FIG> illustrates wire <NUM> pressing against the side of the catheter <NUM> as the catheter is being withdrawn through sheath <NUM> whereby the illustrated portion of catheter <NUM> (i.e. the portion distal of the side-port) is collapsed or deformed. The collapsible nature of this portion of the catheter assists in reducing friction between the wire <NUM> and catheter <NUM>, thereby ensuring that a position of the wire within the true lumen is substantially maintained. In the context of the present invention, and as would be understood by one skilled in the art, it is acceptable for wire <NUM> to be withdrawn a limited distance as catheter <NUM> is retracted, so long as a distal end of wire <NUM> remains in the true lumen whereby the wire is operable to function as a bridge or rail for advancing devices thereover.

In some particular embodiments, the portion of the catheter distal of the side-port is collapsible when a guide-wire is absent from a lumen defined therethrough, i.e. when it is not containing a guide-wire (or another type of wire or wire-shaped device), but retains a non-collapsed or non-deformed configuration when housing a wire or other structure therein.

In some embodiments, the distal tip of the catheter defines a distal end opening or aperture whereby the catheter is operable to be advanced over the guide-wire as an over-the-wire device, or alternatively, a guide-wire may be advanced or withdrawn through the distal end opening of the catheter. As noted above, in some such embodiments, when the portion of the catheter distal of the side-port contains a wire, the wire provides structural (radial) support to the catheter, whereby the distal portion of the catheter housing the wire is operable (has sufficient column strength) to be advanced over the wire and through the anatomy of a patient without ovalization of the catheter, i.e. the catheter retains a non-collapsed configuration.

Thus, the present inventors have conceived and reduced to practice a collapsible tip catheter with a side-port that may be used for re-entry procedures or for advancing into bifurcations. The catheter is sufficiently radially collapsible distal of the side port whereby it has a collapsed configuration which allows the catheter to be withdrawn without altering the position of a wire which is extending through the side-port.

With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of certain embodiments of the present invention only.

<FIG> illustrates an embodiment of a catheter <NUM> including a catheter body <NUM> defining a lumen <NUM> (a primary catheter lumen), a side-port <NUM> in fluid communication with lumen <NUM>, a distal portion <NUM> of catheter body <NUM>, a distal tip <NUM> defining an end opening <NUM> which is in fluid communication with lumen <NUM>, and a marker <NUM>. Distal portion <NUM> is the portion of catheter body <NUM> distal of side-port <NUM>. The marker <NUM> of <FIG> includes a marker band 16a and a marker backbone 16b. In the illustrated embodiment, marker band 16a is proximal of side-port <NUM>, and marker backbone 16b is substantially parallel and opposite to side-port <NUM>. Side-port <NUM> is typically elongated. A wire braid layer <NUM>, shown in the left side of the drawing, ends proximally of side-port <NUM>. Wire braid layer <NUM> is covered by proximal sleeve <NUM>. The embodiment of <FIG> includes side-port <NUM> located in a recess in the outer surface of the catheter, unlike the embodiment of <FIG> (described below) which does not include a recess. In some embodiments, side-port <NUM> is capsule-shaped, having a straight elongate portion with a length about <NUM> ± <NUM> inches (<NUM> ± <NUM>) and curved end portions, each with a radius of about <NUM> ± <NUM> inches (<NUM> ± <NUM>). Some embodiments of the catheter have a shaft length of about <NUM> to <NUM> inches (<NUM> to <NUM>). In a particular embodiment, catheter <NUM> has a shaft length of about <NUM> ± <NUM> inches (about <NUM> ± <NUM>).

In the embodiment of <FIG>, the inner diameter of catheter body <NUM> is about <NUM> ± <NUM> inches (about <NUM> ± <NUM>) at the distal end of wire braid layer <NUM> and is about <NUM> ± <NUM> inches (<NUM> ± <NUM>) at the distal tip of the catheter (i.e. at or about end opening <NUM>). The outer diameter of catheter <NUM> is about <NUM> ± <NUM> inches (<NUM> ± <NUM>) at the distal end of wire braid layer <NUM>. The distance from the proximal end of marker band 16a to the distal tip of the catheter is about <NUM> ± <NUM> inches (<NUM> ± <NUM>). The distance from the distal end of side-port <NUM> to the distal tip of the catheter is about <NUM> ± <NUM> inches (<NUM> ± <NUM>).

Some embodiments of the catheter may be used with a guide-wire with a <NUM> inch (<NUM>) outer diameter (OD), in a 6F introducer sheath with an inner diameter of about <NUM> inches (about <NUM>). When the embodiment of catheter <NUM> of <FIG> is used with a <NUM> inch (<NUM>) guide-wire, the inner diameter of about <NUM> ± <NUM> inches (<NUM> ± <NUM>) at end opening <NUM> will provide a close or tight fit to the guide-wire. The relatively larger inner diameter of about <NUM> ± <NUM> inches (about <NUM> ± <NUM>) at the distal end of wire braid layer <NUM> will provide for trackability over the guide-wire as the larger diameter provides for space around wire <NUM>, which reduces friction and binding.

<FIG> a diagrammatic cut away view of a distal portion of the disclosed catheter illustrating materials of an embodiment of the device. The example of <FIG> comprises a braided shaft <NUM> including a wire braid layer <NUM>. The distal end of braided shaft <NUM> is proximal of side-port <NUM>. In typical embodiments, wire braid layer <NUM> is comprised of a metal, for example, stainless steel or Nitinol. Alternative embodiments of wire braid layer <NUM> are comprised of a polymer such as, for example, nylon, Teflon®, or carbon based thread. Wire braid layer <NUM> is covered by proximal sleeve <NUM>, which in typical embodiments is a polymer, such as, for example, Pebax® (a thermoplastic elastomer) or another type of nylon. In the embodiments of <FIG>, a Pebax layer <NUM> extends distally of braided shaft <NUM> and ends proximal of side-port <NUM>. The distal end of Pebax layer <NUM> abuts Grilamid® layer <NUM> (a plastic comprising a polyamide), which extends distally to Grilamid distal end 12a. Grilamid distal end 12a is between the proximal and distal ends of side-port <NUM> such that there is a transition in the material comprising catheter body <NUM> from Grilamid layer <NUM> to nylon layer <NUM> at the side-port.

In some alternative embodiments, Pebax layer <NUM> is replaced by another polymer, for example, another type of nylon. In some other alternative embodiments, Grilamid layer <NUM> is replaced by another polymer, for example, Pebax or another type of nylon.

The embodiment of <FIG> also illustrates a polytetrafluoroethylene (PTFE) liner extending substantially the entire length of lumen <NUM> (a primary catheter lumen) to facilitate travel over a guide-wire. PTFE liner <NUM> has a substantially constant thickness of about <NUM> ± <NUM> inches (<NUM> ± <NUM>), and in comparison to nylon layer <NUM> and Grilamid layer <NUM>, is relatively flexible (it has modulus of elasticity typically ranging from about <NUM> to <NUM> gigapascals (GPa)), whereby it does not have a substantially significant effect on the rigidity of catheter <NUM>.

Examples of the catheter which are not part of the invention are operable to passively collapse or deform distal of the side-port <NUM>, as described above, as well as being operable to be advanced over a wire without compromising integrity and without experiencing ovalization. Avoidance of ovalization is achieved, for example, by distal portion <NUM> being configured to be sufficiently axially stiff (i.e. having sufficient column strength) to be advanceable (for example, over a guide-wire) while still being sufficiently radially flexible to be passively collapsible. To satisfy the requirements of axial stiffness and radial flexibility, the distal portion of the catheter (distal of the side-port) comprises a layer of material (nylon layer <NUM>) that is stiff enough to provide adequate column strength and, in the disclosed embodiments, is thin enough to provide collapsibility.

Referring to the embodiments of <FIG> and <FIG>, nylon layer <NUM>, which forms a significant part of distal portion <NUM>, is typically a VESTAMID® nylon having stiffness (a modulus of elasticity) of about <NUM> ± <NUM> GPa. Nylon layer <NUM> tapers distally in thickness from about <NUM> ± <NUM> inches (<NUM> ± <NUM>) to about <NUM> ± <NUM> inches (<NUM> ± <NUM>) and in outer diameter from about <NUM> ± <NUM> inches (<NUM> ± <NUM>) to about <NUM> ± <NUM> inches (<NUM> ± <NUM>). As nylon layer <NUM> forms an outer layer of distal portion <NUM>, an outer diameter of nylon layer <NUM> is also an outer diameter of catheter <NUM>. As previously described, in typical embodiments, nylon layer <NUM> is sufficiently stiff such that distal portion <NUM> of catheter <NUM> is advancable over a wire without experiencing ovalization, i.e. while retaining a substantially non-collapsed or non-deformed configuration.

In use, when a catheter <NUM>, for example as described hereinabove, is withdrawn or retracted within a sheath after a wire is extended through side-port <NUM>, distal portion <NUM> will collapse, i.e. will adopt a collapsed or deformed configuration, when force is applied against an outer surface thereof, for example when the wire pushes against it, whereby, in a manner previously described, the catheter can be withdrawn or retracted without substantially retracted the wire <NUM> positioned therethrough. In typical embodiments, distal portion <NUM> is also sufficiently resilient to return to a non-collapsed or non-deformed configuration when the wire is retracted into the catheter lumen, i.e. when the force applied by the wire to the outer surface of distal portion <NUM> is removed.

The embodiment of <FIG> further includes a marker <NUM> comprising radiopaque marker band 16a and marker backbone 16b which may be used to visualize the location of side-port <NUM> under imaging. Marker <NUM> is typically comprised of a radiopaque metal, for example, stainless steel, platinum, or a mixture of platinum and iridium. A proximal portion of marker <NUM>, marker band 16a, is proximal of side-port <NUM> such that marker band 16a may be used for longitudinal positioning of side-port <NUM>. Marker backbone 16b is substantially opposite to side-port <NUM>, i.e. aligned at about <NUM>° relative to the side-port, such that marker backbone 16b is operable to facilitate rotational positioning of side-port <NUM>. Marker backbone 16b may also be used for longitudinal positioning.

In the embodiment of <FIG>, there is a transition in material at or about a location of the side-port <NUM>. Marker backbone 16b extends from marker band 16a (which is proximal of side-port <NUM>) to a location distal of the side-port <NUM> thereby providing support to catheter body <NUM> to compensate, at least in part, for structural weaknesses caused by the side-port and transition of material at that location. Furthermore, Grilamid ® layer <NUM> is stiffer than both Pebax® layer <NUM> and nylon layer <NUM>, thereby providing further support to catheter body <NUM> proximally of the side-port <NUM>, as well as to a portion of the catheter body located at a proximal portion of the side-port <NUM> itself i.e. Grilamid layer <NUM> functions as a support layer. Marker backbone 16b is positioned or embedded in catheter body <NUM> substantially opposite side-port <NUM> and, in some embodiments, extends somewhat distally beyond the side-port <NUM> while avoiding interfering with (i.e. reducing) the collapsibility of distal portion <NUM> of catheter body <NUM>.

<FIG> is an enlarged side cutaway view of marker <NUM>. In the particular illustrated embodiment, the length of marker <NUM> is about <NUM> ± <NUM> inches (<NUM> ± <NUM>), the length of marker backbone 16b is about <NUM> ± <NUM> inches (<NUM> ± <NUM>), the thickness of marker backbone 16b is about <NUM> ± <NUM> inches (<NUM> ± <NUM>), the length of marker band 16a is about <NUM> ± <NUM> inches (about <NUM> ± <NUM>), and the outer diameter of marker band 16a is about <NUM> ± <NUM> inches (<NUM> ± <NUM>). In some alternative embodiments, the length of the length of marker backbone 16b is about <NUM> ± <NUM> inches (<NUM> ± <NUM>).

<FIG> shows an end cutaway or cross-sectional view of the marker of <FIG> through marker band 16a, which has an outer diameter of about <NUM> ± <NUM> inches (<NUM> ± <NUM>) and an inner diameter of about <NUM> ± <NUM> inches (<NUM> ± <NUM>). In some alternative embodiments, marker band 16a has an outer diameter of about <NUM> ± <NUM> inches (<NUM> ± <NUM>) and an inner diameter of about <NUM> ± <NUM> inches (<NUM> ± <NUM>).

<FIG> illustrates a cross-sectional view of a sheath <NUM> containing a catheter body <NUM> and a wire <NUM> extending through a side-port (not shown) of the catheter. Typical embodiments of a catheter body <NUM> have a substantially circular cross sectional shape, and a substantially constant wall thickness, when the catheter is not bent or distorted. Some alternative embodiments have a non-circular cross sectional shape.

<FIG> is a side cutaway view of an alternative embodiment of catheter body <NUM> having elongate support members <NUM> in distal portion <NUM>. Such embodiments of the catheter comprise at least two elongate support members <NUM> for providing longitudinal support while allowing the distal portion to still be collapsible or inwardly deformable. In typical embodiments, elongate support members <NUM> are comprised of a metal, but alternative embodiments could be comprised of other materials having the appropriate support strength.

<FIG> is a cross-sectional view of the embodiment of <FIG> at cut-away line bb illustrating the elongate support members <NUM> arranged in a substantially circular configuration surrounding the primary catheter lumen, lumen <NUM>. In some embodiments, polymer <NUM> is comprised of a biocompatible stretchable polymer, for example, silicone elastomers or polydimethylsiloxane (PDMS). The polymer can be thinner and more deformable relative to an embodiment without elongate support members <NUM> since the elongate support members are providing column strength. Some embodiments further comprise a radiopaque material which coats elongate support members <NUM>.

In the invention, distal portion <NUM> of catheter body <NUM> is operable to collapse inwardly into the primary catheter lumen (lumen <NUM>) and thereby temporarily adopt a reduced profile in a collapsed configuration when a controlled force is applied to the distal portion of the catheter body. <FIG> is a side cutaway view of such an embodiment, wherein catheter body <NUM> has a shape memory element <NUM>. Shape memory element <NUM> can comprise any appropriate structure, for example, a stent or a coil, wherein the shape memory element is configured to produce said controlled force when heated. Wire <NUM> connects shape memory element <NUM> to a source of heat. Some embodiments further comprise a radiopaque material coating the shape memory element. In some such embodiments, polymer <NUM> of the distal portion comprises a biocompatible stretchable polymer.

Some alternative embodiments of catheter <NUM> having a shape memory element <NUM> include a distal portion <NUM> which comprises a shape memory element <NUM>, wherein the shape memory element is configured to expand and produce an expanding force in distal portion <NUM> when heated, whereby the distal portion expands (i.e. adapts an expanded configuration) to thereby allow advancement of the distal portion over a guide-wire. In such embodiments, distal portion <NUM> of catheter body <NUM> is operable to collapse inwardly into the primary catheter lumen when shape memory element <NUM> not heated, thereby adopting a reduced profile in a collapsed configuration.

Embodiments of the present invention may be used, for example, when withdrawing or retracting a re-entry catheter (either through a lumen or through tissue) having a wire positioned through a side-port of the catheter (into a true vessel lumen) or when withdrawing a bifurcation catheter having a wire positioned through a side-port of the catheter (into a branch artery or vein).

One embodiment of the invention is for a method of using the catheter of <FIG> or <FIG>, wherein distal portion <NUM> has an outer diameter which tapers from about <NUM> ± <NUM> inches (<NUM> ± <NUM>) to about <NUM> ± <NUM> inches (<NUM> ± <NUM>), and the catheter is used with a guide-wire with a <NUM> inch (<NUM>) outer diameter and a 6F introducer sheath (with an inner diameter of about <NUM> inches or about <NUM>), wherein the method comprises withdrawing the catheter from the sheath with the guide-wire extending through the side-port.

Example <NUM> - A catheter comprising a catheter body, the catheter body defining at least a primary catheter lumen and at least one side-port in communication with the primary catheter lumen, and a distal portion of the catheter extending distal to the at least one side-port, the side-port being configured to allow travel of a device (a wire or other component) therethrough, wherein the distal portion of the catheter is radially collapsible.

Example <NUM> - The catheter of example <NUM>, wherein the distal portion of the catheter body is operable to collapse inwardly into the primary catheter lumen and thereby temporarily adopt a reduced profile in a collapsed configuration when force is applied to an outer surface of the distal portion of the catheter body.

The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.

Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Claim 1:
A catheter (<NUM>) for use with a wire (<NUM>) or other component comprising a catheter body (<NUM>), the catheter body (<NUM>) defining at least a primary catheter lumen (<NUM>) and at least one side-port (<NUM>) in communication with the primary catheter lumen (<NUM>), a distal portion (<NUM>) of the catheter body (<NUM>) extending distal of the at least one side-port (<NUM>),
characterized in
that the side-port (<NUM>) is configured to allow travel of a wire (<NUM>) or other component therethrough, wherein the distal portion (<NUM>) of the catheter body (<NUM>) is operable to collapse inwardly into the primary catheter lumen (<NUM>) and thereby temporarily adopt a reduced profile in a collapsed configuration when a force is applied to an outer surface of the distal portion (<NUM>) of the catheter body (<NUM>), the collapsed configuration allowing for the catheter to be withdrawn without altering the position of the wire (<NUM>) or other component extending through the side-port (<NUM>).