Patent Description:
Chronic total occlusions (CTO] can be found in coronary angiography, occurring in approximately <NUM>-<NUM>% of patients with documented coronary artery disease. Percutaneous revascularization (angioplasty] is attempted in less than <NUM>% of CTOs. Approximately <NUM>% of cases undergo bypass surgery, while the majority (approximately <NUM>%] are treated medically. The main reasons for not attempting percutaneous revascularization include the frequent presence of multi-vessel disease, and the complexity and time requirements of performing these technically challenging percutaneous procedures.

About <NUM>% of percutaneous revascularization procedures are successful. This is primarily due to the difficulty in crossing the occlusion with guidewires in the antegrade direction. A challenge is crossing the fibrotic and often calcified material that is occluding the artery and then re-entering the true lumen beyond the occluded segment. In some cases, the guidewire immediately re-enters the true lumen at the end of the CTO (just past the distal end], which is known as true-true crossing. However, in many cases, the guidewire cannot cross the occlusion, but is in a subintimal position after the occlusion and has to re-enter the true lumen further downstream - so called true to false to true. In some cases, downstream re-entry can be done by reshaping the tip of CTO specialty guidewires advanced through a central lumen microcatheter (such as finecross or corsair] and directing the guidewire back into the true lumen. Also, angulated microcatheters can be used, but control of the angle of the tip can be challenging in the subintimal space.

More recently, a specialized CTO device has been introduced that first involves advancing a catheter (known as the CrossBoss], which is a proximal torque device that utilizes bidirectional rotation with a fast-spin technique, in order to advance across the occlusion as the spin reduces the push required. Although this catheter can be advanced within the luminal space, it is usually advanced within the subintimal space and then the CrossBoss catheter is replaced with a special flat balloon that has two holes at different orientations (Stingray balloon] through which the operator advances a very stiff guidewire (Stingray wire] to re-enter the artery. This is a technically challenging procedure that requires extensive training and has been restricted so far to highly expert operators.

Subintimal positioning of the guidewire (i.e. inside the wall of the coronary artery rather than the true lumen] after crossing the occlusion is a major problem and common failure more in CTO PCI, and highlights the need for additional options to facilitate re-entry into the true lumen of the artery after the occlusion. <CIT> discloses a catheter for recanalizing a blood vessel having an occlusion therein via a subintimal pathway. The catheter includes a catheter shaft having an inflatable balloon mounted to the distal end portion of the catheter shaft. A flexible tubular member extends from the catheter shaft and along an exterior of the inflatable balloon Inflation of the inflatable halloon deflects the flexible tubular member into a deflected configuration away from a longitudinal axis of the catheter shaft to effect re-entry into the true lumen distal of the occlusion. International patent application publication No. <CIT> discloses a method for thermal bonding of an inverted balloon neck on a catheter, including placing an inverted balloon neck on a shaft of a catheter, and characterized by applying heat at an internal hollow of the shaft where the inverted balloon neck is placed, while applying internal pressure to attach an external surface of the shaft (<NUM>) to the inverted balloon neck. <CIT> discloses a method and apparatus for crossing an obstruction in a tubular member, and more particularly to a medical device method for crossing of a chronic occlusion in a subintimal or interstitial space of an artery.

The present invention is defined in independent claim <NUM> and subsequent dependent claims <NUM> - <NUM>.

The present disclosure addresses the aforementioned challenges by providing a catheter device designed for lumen re-entry, which may be used for percutaneous CTO revascularization and other applications, such as angioplasty procedures where it can be challenging to position a guidewire in a side branch vessel with a difficult angulation.

It is an aspect of the present disclosure to provide a catheter that includes a catheter shaft having a tubular wall that extends from a proximal end to a distal end along a longitudinal axis to define a lumen. The tubular wall having formed therein an inner lumen that extends from the proximal end to the distal end of the catheter shaft. The catheter device also includes a deflection member coupled to the distal end of the catheter shaft and in fluid communication with the inner lumen such that fluid provided to the inner lumen causes the deflection member to expand from a first volume to a second volume that is larger than the first volume. When the deflection member is in the second volume, it extends from a surface of the tubular wall towards the longitudinal axis of the catheter shaft to provide a surface for deflecting an interventional device extending through the lumen and outward from the distal end of the catheter shaft at a deflection angle.

The foregoing and other aspects and advantages of the disclosure will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the disclosure. Such embodiment does not necessarily represent the full scope of the disclosure, however.

By way of overview and introduction, a catheter device that can provide subintimal orientation and re-entry into a lumen is generally illustrated in <FIG>. As will be described, one advantageous clinical use of the catheter device is treatment of chronic total occlusions ("CTO"]. The catheter device can also be used for other vascular treatment applications, such as the placement of stents and angioplasty balloons, deflection of guidewires into angulated side branches from an intraluminal position, orientation of a guidewire at the beginning of occlusion to engage a CTO proximal to the CTO and at an angle that is not parallel to the artery, and non-vascular treatment applications. Generally, the catheter device can include an orientation subsystem and a re-entry subsystem. Embodiments of the re-entry subsystem will be described with respect to <FIG>. Embodiments of the orientation subsystem will be described with respect to <FIG>.

Referring now to <FIG>, the catheter <NUM> includes a catheter shaft
<NUM> extending from a proximal end <NUM> to a distal end <NUM> along a longitudinal axis <NUM> to define a lumen <NUM>. A deflection member <NUM> is coupled to the shaft <NUM> at the distal end <NUM> of the catheter <NUM>. The deflection member <NUM> generally includes an expandable membrane that when filled with a fluid expands from a first volume (e.g., a deflated volume] to a second volume (e.g., an inflated or expanded volume]. When expanded to the second volume, the deflection member <NUM> provides a surface for deflecting a guidewire, or other interventional device, extending through the lumen <NUM> outward through a distal opening <NUM> of the catheter shaft <NUM>. As will be described below, the expanded volume of the deflection member <NUM> provides a surface that will deflect the guidewire, or other interventional device, a deflection angle, θ , when exiting the opening <NUM> at the distal end <NUM> of the catheter <NUM>.

The wall of the catheter shaft <NUM> has formed therein an inner lumen <NUM> extending from the proximal end <NUM> to the distal end <NUM> of the catheter <NUM>. The inner lumen <NUM> receives a hypotube <NUM> that is in fluid communication with the deflection member <NUM>. The deflection member <NUM> generally spans an aperture <NUM> formed as the distal end of the inner lumen <NUM>, or any hypotube <NUM> provided to the inner lumen <NUM>. The aperture <NUM> can be formed in the distal end of the inner lumen <NUM>, as shown in <FIG> and IB, or alternatively can be formed along the outer surface of the inner lumen <NUM> and through the catheter shaft <NUM> such that the deflection member <NUM> can be operated in a side-firing arrangement into the interior lumen <NUM> of the catheter shaft <NUM>. Providing a fluid to the hypotube <NUM> causes the deflection member <NUM> to expand from the first volume to the second volume. By controlling the amount of fluid provided to the deflection member <NUM> via the hypotube <NUM>, the second volume, and thereby the deflection angle, Θ , provided by the deflection member <NUM>, can be similarly controlled. Thus, by controlling the expanded volume of the deflection member <NUM>, a guidewire, or other interventional device, can be deflected into the true lumen of a blood vessel when the catheter <NUM> is positioned in the subintimal space.

In some other embodiments, more than one deflection member <NUM> can be provided at the distal end <NUM> of the catheter <NUM>. In these configurations, a similar number of inner lumens <NUM> are formed in the wall of the catheter shaft <NUM> such that a different hypotube <NUM> may be provided to each inner lumen <NUM> to be in fluid communication with one of the deflection members <NUM>.

In some embodiments, the wall of the catheter shaft <NUM> does not include an inner lumen <NUM>; rather, the hypotube <NUM> is provided to the interior surface of the lumen <NUM> of the catheter shaft <NUM>. In such configurations, it will be appreciated that more than one hypotube <NUM> can be similarly provided to the interior surface of the lumen <NUM> of the catheter shaft <NUM>. It will also be appreciated that in some embodiments a hypotube <NUM> can be provided to both an inner lumen <NUM> formed in the wall of the catheter shaft <NUM>, and to the interior surface of the lumen <NUM> of the catheter shaft <NUM> itself.

The wall of the catheter shaft <NUM> can be chamfered or beveled such that the wall slopes proximally toward the distal opening <NUM> of the catheter <NUM>, thereby defining an angled surface <NUM>. The angled surface <NUM>, in turn, defines a maximum deflection angle at which a guidewire, or other interventional device, can be deflected upon exiting the opening <NUM> at the distal end <NUM> of the catheter <NUM>. In some configurations, the exterior surface of the catheter shaft <NUM> may be inwardly tapered distal to a taper line <NUM> towards the distal end <NUM> of the catheter <NUM>.

As mentioned above, and as shown in <FIG> and IB, the catheter <NUM> can receive a guidewire <NUM> that can be fed through the lumen <NUM> from the proximal end <NUM> to the distal end <NUM> of the catheter <NUM>. The guidewire <NUM> can be directed through the opening <NUM> at the distal end <NUM> of the catheter <NUM> via contact with the deflection member <NUM> and the angled surface <NUM> of the catheter shaft <NUM>. That is, the guidewire <NUM> is deflected by contact with the deflection member <NUM> so as to extend outward from the distal opening <NUM> at the deflection angle.

The deflection member <NUM> is generally constructed as an expandable membrane that spans the aperture <NUM> in the catheter shaft <NUM> formed by the inner lumen <NUM>. In some other configurations, the deflection member <NUM> can be constructed as an expandable membrane that spans the opening of the hypotube <NUM>. That is, the deflection member <NUM> can be coupled to the catheter shaft <NUM> or to the hypotube <NUM>. As described above, fluid is provided to the deflection member <NUM> via the hypotube <NUM> to expand the deflection member from a first volume to a second volume. The deflection member <NUM> can have a partially spherical shape; although, other shapes can also be implemented, such as partially ellipsoidal shapes and the like. The deflection member <NUM> can extend outwardly from the distal end <NUM> of the catheter <NUM> along a direction perpendicular, or nearly perpendicular, to the angled surface <NUM> of the catheter shaft <NUM>.

In some embodiments, the deflection member <NUM> can be constructed as an extruded sleeve that spans the aperture <NUM> in the catheter shaft <NUM> formed by the inner lumen <NUM>. Alternatively, the extruded sleeve can span a first aperture that is formed in the hypotube <NUM>, which is aligned with a suitable second aperture in the catheter shaft <NUM>, such as aperture <NUM>. An example of this configuration in an undeployed state is shown in <FIG> and in a deployed state in <FIG>. In this example, the aperture <NUM> in the catheter shaft <NUM> formed by the inner lumen <NUM> terminates on the inner surface of the catheter shaft <NUM> such that the deflection member <NUM> will be deployed in a side-firing configuration. The deflection member <NUM> is also shown in this example as a balloon that is inflated when fluid is provided through the hypotube <NUM> to the interior volume of the deflection member <NUM> in its undeployed state. As noted, the deflection member <NUM> in this example can be constructed as an extruded sleeve <NUM>. The deflection member <NUM> can also be constructed by dipping the catheter shaft <NUM> or hypotube <NUM> in a suitable material to form the deflection member <NUM> in its undeployed state. The deflection member <NUM> can be composed of silicon, polyurethane, silicone polypropylene , PEBAX® (Arkema; Colombes, France], or other suitable expandable material, which may include a polymer, elastomer, or so on.

In some other embodiments, the deflection member <NUM> can be constructed as a patch <NUM> made by an extruded sleeve that spans the aperture <NUM> in the catheter shaft <NUM> formed by the inner lumen <NUM>. Alternatively, the patch <NUM> can span a first aperture that is formed in the hypotube <NUM>, which is aligned with a suitable second aperture in the catheter shaft <NUM>, such as aperture <NUM>. The patch <NUM> can also be formed by dipping the catheter shaft <NUM> or hypotube <NUM> in an expandable material that spans the aperture <NUM> in the catheter shaft, or an aperture formed in the hypotube <NUM>. An example of this configuration is shown in an undeployed state in <FIG> and in a deployed state in <FIG>. In this example, the aperture <NUM> in the catheter shaft <NUM> formed by the inner lumen <NUM> terminates on the inner surface of the catheter shaft <NUM> such that the deflection member <NUM> will be deployed in a side-firing configuration. The patch <NUM> can span a portion of the circumference of the catheter shaft <NUM> or hypotube <NUM>, as shown in FIG. The deflection member <NUM> is also shown in this example as a balloon that is inflated when fluid is provided through the hypotube <NUM> to the interior volume of the deflection member <NUM> in its undeployed state. As noted, the deflection member <NUM> in this example can be constructed as a patch <NUM> made by an extruded sleeve or by dipping the catheter shaft <NUM> or hypotube <NUM> in a suitable material to form the deflection member <NUM> in its undeployed state. The deflection member <NUM> can be composed of silicon, polyurethane, silicone polypropylene, PEBAX® (Arkema; Colombes, France], or other suitable expandable material, which may include a polymer, elastomer, or so on.

As described above, when a fluid is provided to the deflection member <NUM> via the hypotube <NUM>, the deflection member <NUM> expands from the first volume to a second volume. When the deflection member <NUM> has the second volume it partially extends into the opening <NUM> at the distal end <NUM> of the catheter <NUM>, thereby providing a surface that will deflect a guidewire, or other interventional device, passing through the opening <NUM> at the distal end <NUM> of the catheter <NUM>. As one non-limiting example, when the deflection member <NUM> has the first volume, the deflection member <NUM> has a substantially flat shape. That is, the deflection member <NUM> can be relatively flat against the angled surface <NUM> of the catheter shaft <NUM>. In some other embodiments, the deflection member <NUM> can be partially protruding from, or partially recessed relative to, the angled surface <NUM> of the catheter shaft <NUM>. As the pressure supplied to the deflection member <NUM> by the fluid is decreased, the deflection member <NUM> can begin to compress and transition from the expanded shape at the second volume to the flatter shape against the angled surface <NUM> at the first volume. It should be appreciated that the deflection member <NUM> can be partially expanded, thereby expanding the deflection member <NUM> into an intermediate position.

In some embodiments, the catheter <NUM> is constructed to be a microcatheter. As one example, the catheter <NUM> can be constructed as a microcatheter for use in coronary arteries. Thus, in some non-limiting examples, the catheter <NUM> can be sized at <NUM> Fr (<NUM>] or less. As another example, the catheter <NUM> can be constructed to be a microcatheter for use in peripheral arteries, which can allow a larger outer diameter than in coronary microcatheter implementations.

Referring to <FIG>, a view looking down the catheter shaft <NUM> from the distal end <NUM> of the catheter <NUM> is shown with the deflection member <NUM> at the first volume (<FIG>] and at the second volume (<FIG>]. As shown, the catheter shaft <NUM> can be a tubular structure that defines the lumen <NUM> within the tubular structure of the catheter shaft <NUM>. The catheter shaft <NUM> is generally composed of a medical device class VI approved polymer material, such as, for example, polyethylene terephthalate ("PET"]; however, other polymer materials could also be employed, such as other related PET formulations, polyethylene naphthalate ("PEN"], polyether ether ketone ("PEEK"], and polyether block amide ("PEBA"], such as PEBAX® (Arkema; Colombes, France].

In some embodiments, the catheter can be composed of more than one material. As one example, the catheter shaft can have first layer composed of a first material and a second layer composed of a second material. In such embodiments, the first layer can correspond to the inner surface of the catheter shaft <NUM> and the second layer can correspond to the outer surface of the catheter shaft <NUM>. The first layer can be thin, such as <NUM>", and the second layer can be molded around the first layer and any hypotubes <NUM> positioned in the wall of the catheter shaft <NUM>. As one benefit, this two- layered composition can facilitate creating a varied outer diameter for the catheter shaft <NUM>, such as creating a tapered outer surface for the catheter shaft <NUM>, as described above. In these embodiments, the deflection member <NUM> can be molded into the first layer. In other embodiments, the deflection member <NUM> can be formed by applying a thin membrane (e.g., a thin membrane of latex plastic or other such material] across a hypotube <NUM>.

Referring to <FIG>, another example of a catheter <NUM> of the present disclosure is illustrated. In this example, the catheter <NUM> generally includes a catheter shaft <NUM> extending from a proximal end <NUM> to a distal end <NUM> along a longitudinal axis <NUM> to define a lumen <NUM>. In this example, the catheter <NUM> is generally constructed such that the catheter shaft <NUM> includes a single inner lumen <NUM>. As shown, the inner lumen <NUM> is generally positioned on a first side <NUM> of the catheter shaft <NUM>. In some configurations, the second side <NUM> of the catheter shaft <NUM> can have a thinner outer wall than the first side <NUM>. As mentioned above, in some embodiments the hypotube <NUM> may be provided to the interior surface of the lumen <NUM> of the catheter shaft <NUM> rather than an inner lumen <NUM> formed in the wall of the catheter shaft <NUM>.

The catheter shaft <NUM> can be constructed to have an extended portion <NUM> of the wall of the catheter shaft <NUM> that extends distally beyond the opening <NUM>. As shown, the extended portion <NUM> of the wall of the catheter shaft <NUM> extends more distal on the first side <NUM> of the catheter shaft. The portion of the wall of the catheter shaft <NUM> that does not include the extended portion <NUM> may be tapered to a thinner thickness than an opposing portion of the wall of the catheter shaft <NUM>. The extended portion <NUM> of the catheter shaft <NUM> can span one-half of a circumference of the catheter shaft <NUM>, or may span more or less than one-half of the circumference of the catheter shaft <NUM>.

In these embodiments, the inner lumen <NUM> terminates in the extended portion <NUM> of the catheter shaft <NUM> without opening to the distal end <NUM> of the catheter shaft <NUM>. However, an aperture <NUM> is formed on the inner surface of the catheter shaft <NUM>, such that the inner lumen <NUM> is open to the inner surface of the catheter shaft <NUM> by way of the aperture <NUM>. The deflection member <NUM> in this configuration can be coupled to the inner surface of the catheter shaft <NUM> and can be made to span the aperture <NUM> such that the deflection member <NUM> is in fluid communication with a hypotube <NUM> provided to the inner lumen <NUM>. The deflection member <NUM> can have a generally hemi-spherical shape that provides a deflection member <NUM> that is "side-firing" in the sense that the deflection member <NUM> expands into the lumen <NUM> of the catheter shaft <NUM> towards the longitudinal axis <NUM> of the catheter <NUM> when expanding from the first volume to the second volume.

The deflection member <NUM> is coupled to the aperture <NUM>, such that the aperture <NUM> provides fluid communication between the deflection member and the hypotube <NUM> positioned in the inner lumen <NUM> to provide a fluid to the deflection member <NUM>. The fluid provided to the deflection member <NUM> can facilitate expansion of the deflection member <NUM> to the second volume as described above. The deflection member <NUM> at the second volume partially extends into the distal opening <NUM> of the catheter <NUM> to provide a surface that will deflect a guidewire or other interventional device extending through the lumen <NUM> of the catheter shaft <NUM> by a projection angle, Θ. At the first volume, the deflection member <NUM> can have a substantially flat shape. As fluid is removed from the deflection member <NUM> its volume will decrease again from the second volume to the first volume. It should be appreciated that the deflection member <NUM> can be partially expanded, thereby expanding the deflection member <NUM> to an intermediate volume.

One example of the embodiment of the catheter <NUM> as described above can be sized at <NUM> Fr (<NUM>]. In such embodiments, the catheter <NUM> can be a referred to as a microcatheter. In some implementations, the catheter <NUM> may be sized for use in coronary arteries, and in some other implementations the catheter <NUM> may be sized for use in peripheral arteries.

In another embodiment, the catheter shaft <NUM> can be constructed to be angled at its distal end <NUM>, as shown in <FIG>, such that the catheter shaft <NUM> extends distally farther on one side <NUM> than on the other side <NUM> forming a sloped outer surface to the distal end <NUM> of the catheter shaft <NUM>. In these instances, the inner lumen <NUM> may terminate within the wall of the catheter shaft <NUM>. Like the embodiments described with respect to <FIG>, an inward facing aperture <NUM> is formed in the wall of the catheter shaft <NUM> to provide fluid communication between the inner lumen <NUM> and a deflection member <NUM> coupled to the aperture <NUM>. As described above, a hypotube <NUM> can be provided in the inner lumen <NUM>, or the lumen <NUM> of the catheter shaft <NUM>, to facilitate providing a fluid to the deflection member <NUM> to adjust the volume of the deflection member <NUM> between the first volume and the second volume. In the configuration shown in <FIG>, the deflection member <NUM> is arranged opposite the lower side <NUM> of the catheter shaft <NUM> at its distal end <NUM>.

In another embodiment of the catheter <NUM>, a positioning member <NUM> can be coupled to the catheter shaft <NUM> at the distal end <NUM> of the catheter <NUM>, as shown in <FIG>. The positioning member <NUM> can be coupled adjacent a deflection member <NUM>, such that expanding the deflection member <NUM> from a first volume to a second volume will deflect or otherwise articulate the positioning member <NUM> from a first position to a second position. As an example, in the second position the positioning member <NUM> can provide a surface for deflecting a guidewire or other interventional device by a deflection angle.

As one example of the embodiments described above, the catheter <NUM> can be sized at <NUM>. 5Fr (<NUM>]. In some implementations, the catheter <NUM> may be sized for use in coronary arteries, and in some other implementations the catheter <NUM> may be sized for use in peripheral arteries.

In operation, the catheter <NUM> should be properly oriented within the subintimal space, so as to ensure that the guidewire, or other interventional device, extending through the lumen <NUM> of the catheter <NUM> will be deflected back into the true lumen of the blood vessel. To this end, the catheter <NUM> can be constructed to include a radiopaque orientation marker that uniquely indicates the orientation of the catheter shaft <NUM> within the subintimal space. The catheter <NUM> can also include a realignment assembly that can be used to reorient the catheter <NUM> while it resides in the subintimal space, such that the deflection of the guidewire, or other interventional device, will be made into the true lumen of the blood vessel.

Referring now to <FIG>, one example of a radiopaque orientation marker <NUM> that is disposed on the catheter shaft <NUM> of the catheter <NUM> is shown. The radiopaque orientation marker <NUM> can be positioned on the catheter shaft <NUM> proximal to a taper line <NUM>, such as those described above. The radiopaque orientation marker <NUM> is composed of a radiopaque material and generally has an asymmetrical shape around the outer surface of the catheter shaft <NUM>. The asymmetrical shape provides an indication of the orientation of the catheter <NUM> based on the shape displayed to a user. The catheter <NUM> can be rotated as will be discussed below, and the rotation of the catheter <NUM> changes a view of the radiopaque marker <NUM>. As shown in <FIG>, the radiopaque orientation marker <NUM> may be shaped such that when oriented in a first orientation and viewed along a particular line-of-sight the radiopaque orientation marker <NUM> will be displayed as a "C- shaped" object in an x-ray image. When the radiopaque orientation marker <NUM> is rotated to a second orientation and viewed along the same line-of-sight, the radiopaque orientation marker <NUM> will be displayed as a "Z-shaped" object in an x-ray image. Thus, based on the unique shape of the radiopaque orientation marker <NUM>, a user can visualize the current orientation of the catheter in an x-ray image. It will be appreciated that the radiopaque orientation marker <NUM> could also be composed of a material that renders it visible in images acquired with other medical imaging modalities, such as magnetic resonance imaging.

To adjust the orientation of the catheter <NUM>, a realignment assembly can be implemented. As shown in <FIG>, the realignment assembly <NUM> can generally include a rod <NUM> that is provided to the catheter shaft <NUM> of the catheter <NUM>. The rod <NUM> interfaces with a receiving portion <NUM> in the catheter shaft <NUM>, at which the rod <NUM> becomes coupled to the catheter shaft <NUM>. When interfaced with the receiving portion <NUM> of the catheter shaft <NUM>, rotation of the rod <NUM> will result in a rotation of the catheter shaft <NUM>, at least at the distal end <NUM> of the catheter <NUM>, thereby providing a realignment, or reorientation, of the catheter shaft <NUM>.

In the embodiment shown in <FIG>, the receiving portion <NUM> includes protrusions <NUM> disposed on the interior wall of the catheter shaft <NUM>. These protrusions <NUM> create a decreased diameter of the lumen <NUM> of the catheter shaft <NUM>. The protrusions <NUM> may be curved or otherwise shaped to provide a reduced diameter of the lumen <NUM> of the catheter shaft <NUM>. The protrusions <NUM> can be semi-deformable. When the rod <NUM> is provided to the receiving portion <NUM>, the protrusions <NUM> will contact the distal end of the rod <NUM>, thereby creating an interference fit between the rod <NUM> and the receiving portion <NUM>. In this arrangement, the rod <NUM> becomes mechanically coupled to the catheter shaft <NUM> such that when the rod <NUM> is rotated it provides a rotation of the catheter shaft <NUM>.

In one embodiment, shown in <FIG>, the realignment assembly
<NUM> can include a rod <NUM> that is tapered at its distal end. The receiving portion <NUM> of the catheter shaft <NUM> is similarly tapered to receive the tapered rod <NUM>. The tapering of the receiving portion <NUM> provides a tapered fit with the rod <NUM> such that the rod <NUM> becomes mechanically coupled to the catheter shaft <NUM> when interfaced with the receiving portion <NUM>. As such, when the rod <NUM> is rotated it provides a rotation of the catheter shaft <NUM>.

In another embodiment shown in <FIG>, the realignment assembly <NUM> can include a rod <NUM> that is shaped at its distal end to mate with the receiving portion <NUM> of the catheter shaft <NUM>. For example, the rod <NUM> and receiving portion <NUM> can collectively define a "lock and key" mechanism. The receiving portion <NUM> can include an annular stopper <NUM> coupled to the inner wall of the catheter shaft <NUM> and having one or more notched recesses <NUM> that receive similarly shaped protrusions <NUM> extending distally from the distal end of the rod <NUM>. In some configurations, such as the one shown in <FIG>, the notched recesses can be mirrored curved recesses that are recessed from the proximal surface of the stopper <NUM> opposite each other. The keyed end of the rod <NUM> can have a cylindrical central member <NUM> and opposing curved protrusions <NUM> that are shaped to interface with the recesses <NUM> and the annular stopper <NUM>. When the keyed end of the rod <NUM> is interfaced with the recesses <NUM> in the annular stopper <NUM>, the rod <NUM> becomes mechanically coupled to the catheter shaft <NUM> such that when the rod <NUM> is rotated it provides a rotation of the catheter shaft <NUM>.

Referring to <FIG>, at its proximal end the rod <NUM> can have a handle <NUM> that is cylindrical in shape with a tapered distal end that tapers radially inward to meet the rod <NUM>. The outer surface of the handle <NUM> can feature a plurality of ribs <NUM> having a raised profile and extending along a length of the outer surface of the handle <NUM>. The rod <NUM> can be generally cylindrical in shape and can extend to any appropriate length to its distal end. Referring to <FIG>, as another example, the handle <NUM> of the rod <NUM> can be generally cone-shaped being tapered radially inward to meet the rod <NUM> at a distal end of the handle <NUM>. Referring to <FIG>, as another example, handle <NUM> of the rod <NUM> can have a proximal body <NUM> that is generally spherical in shape and a distal body <NUM> that is generally cylindrical in shape and interfaces with the rod <NUM>.

Having generally described the features of the various embodiments of the catheter <NUM>, a discussion of its general mode of operation is provided. By way of example, the operation of the various embodiments of the catheter <NUM> will be described with respect to treatment of chronic total occlusions in a patient. The catheter <NUM> can be configured as a re-entry component for re-entering a true lumen of a patient once the catheter <NUM> has been oriented at a desired orientation in the subintimal space. In percutaneous revascularization therapy, it is desirable to have the catheter <NUM> positioned after the chronic total occlusionfs] prior to re-entry in order to facilitate the procedure. As noted above, it should be appreciated by those skilled in the art that the catheter <NUM> can be employed for other procedures.

The catheter <NUM> can be positioned in the subintimal space of a patient near an occlusion designated for treatment. The deflection member <NUM> receives fluid from a hypotube <NUM> disposed within the inner lumen <NUM> or provided to the interior surface of the lumen <NUM> of the catheter shaft <NUM>, and the fluid causes the deflection member <NUM> to expand from the first volume to the second volume. The fluid supplied to the deflection member <NUM> can be controlled by a user at a proximal end <NUM> of the catheter <NUM>. As one example, the fluid can be supplied via a syringe, similar to those used in balloon catheters.

When the deflection member <NUM> is expanded to the second volume, it partially extends into the distal opening <NUM> of the catheter <NUM> to provide a surface that will deflect a guidewire or other interventional instrument by a projection angle, Θ. It will be appreciated that during a percutaneous revascularization procedure multiple different guidewires can be interchangeably used with the catheter <NUM>. For instance, the guidewire can be changed for a stiffer or slippery guidewire to penetrate through the subintimal tissue to facilitate reentry into the vessel lumen. The deflection surface can be positioned on an interior side of the deflection member <NUM> such that when the guidewire <NUM> extends through the distal opening <NUM> of the lumen <NUM> of the catheter <NUM>, , the guidewire <NUM> will make contact with and be deflected by the surface of the deflection member. Contact between the surface of the deflection member <NUM> and the guidewire <NUM> deflects the guidewire <NUM> through the distal opening <NUM> along the projection angle, Θ. The guidewire <NUM> may also contact the angled surface <NUM> that provides proximal support to the guidewire <NUM> when deflected through the distal opening <NUM>. The guidewire <NUM> can extend distally from the distal end <NUM> of the catheter device along the projection angle, Θ. The projection angle, θ , can be determined by a user pre-operatively or during operation in order to facilitate re-entry into the true lumen beyond the occlusion and can be selectively controlled by adjusting the volume of the deflection member <NUM> as needed. The catheter <NUM> can then be advanced over the guidewire <NUM> into the true lumen beyond the occlusion.

During revascularization therapy using the catheter devices described in the present disclosure, it is generally desirable for the user to understand an orientation of the catheter device in order to determine the proper projection angle and to ensure the catheter device is oriented properly such that the projection angle is positioned for re-entry into the true lumen. Accordingly, the radiopaque orientation marker <NUM> described above and shown in <FIG> can be used to assist in alignment of the catheter <NUM>. The asymmetrical shape of the radiopaque orientation marker <NUM> provides an indication of the orientation of the catheter <NUM> based on the appearance of the shape of the radiopaque orientation marker <NUM> displayed in an x-ray or other medical image of the catheter <NUM>.

Rotation of the catheter <NUM> to a desired orientation can be achieved using the realignment assembly described above. By causing rotation of the rod <NUM> while it is interfaced with the receiving portion <NUM> of the catheter shaft, the catheter <NUM> can be rotated between different orientations. The rod <NUM> can be stiff and allow for increased translation of rotation applied by a user at the handle <NUM> located at the proximal end of the rod <NUM>. The rod <NUM> can also provide support along the length of the catheter shaft <NUM> to rotate the catheter shaft <NUM> without kinking. Once the desired orientation is achieved, the rod <NUM> can be removed from the lumen <NUM> of the catheter shaft <NUM> and then be replaced with a guidewire for re-entry into the true lumen as discussed above.

Thus, as one non-limiting example of its use, the catheter <NUM> will be oriented in the proper direction beyond the occlusion using the radiopaque orientation marker <NUM> and the orientation rod <NUM>. A guidewire will be advanced to the tip of the catheter <NUM>, beside the uninflated deflection member <NUM>. The deflection member <NUM> will then be expanded, angling the guidewire into the vessel lumen. The guidewire will then be advanced into the true lumen beyond the occlusion. The catheter <NUM> will then be advanced over the guidewire and into the true lumen to secure the position. After the guidewire has been advanced into the distal lumen, the catheter <NUM> in the subintimal space may be exchanged for a balloon catheter or different microcatheter while maintaining the wire position in the distal lumen.

As described, the catheter <NUM> can be used in CTO interventions, specifically directing a guidewire from the subintimal space towards the true lumen. The catheter <NUM> can also be used for directing a guidewire down a difficult to access side branch (in narrowed but not occluded arteries], for example.

Referring now to <FIG>, an example method for using the catheter <NUM> described in the present disclosure for a subintimal re-entry procedure is shown. A section of an artery with a chronic total occlusion is shown in <FIG>. A surgeon positions a guidewire to enter the subintimal space proximal to the occlusive plaque, as shown in <FIG>. The microcatheter is then tracked over the guidewire into the subintimal space, as shown in <FIG>. The microcatheter is in the correct orientation for re-entry to the true lumen, as indicated by the "C" shaped marker facing towards the true lumen. If, however, the microcatheter is tracked over the guidewire into the subintimal space and catheter is not in the correct orientation for re-entry to the true lumen, as shown in <FIG> and indicated by the backwards "Z" shaped marker facing towards the true lumen, the orientation rod is inserted into the microcatheter to re-orient the microcatheter until the "C" shaped marker faces towards the true lumen. The guidewire is then pulled back inside the microcatheter until just the distal tip of the guidewire protrudes out of the opening, as shown in <FIG>. The expandable membrane of the deflection member is then inflated to angulate the distal tip of the guidewire, which can then be advanced to re-enter the true lumen, as shown in <FIG>. The catheter is then advanced over the guidewire into the true lumen, as shown in <FIG>. Alternatively, the guidewire is advanced into the distal lumen, and the microcatheter is withdrawn and can be replaced with a different catheter.

Referring now to <FIG>, an example method for using the catheter
<NUM> described in the present disclosure for accessing a difficult to reach side branch is shown. In this example, the difficult to reach side branch is in an atherosclerotic right coronary artery, as shown in <FIG> OA. A surgeon positions a guidewire to enter the right coronary artery, but cannot access the side branch, as shown in <FIG>. The microcatheter is tracked over the guidewire, as shown in <FIG>. In this example, the microcatheter is in the correct orientation for angulating the guidewire into the side branch, as indicated by the "C" shaped marker facing towards the side branch. If, however, the microcatheter is tracked over the guidewire and is not in the correct orientation for angulating the guidewire into the side branch, as shown in <FIG> and indicated by the backwards "Z" shaped marker facing towards the side branch, then the orientation rod is inserted into the microcatheter to re-orient the microcatheter until the "C" shaped marker faces towards the side branch. The guidewire is then pulled back inside the microcatheter until just the distal tip of the guidewire protrudes out of the opening, as shown in <FIG>. The expandable membrane of the deflection member is inflated to angulate the distal tip of the guidewire, which can then be advanced to enter the side branch, as shown in <FIG> OF. When the guidewire successfully accessed the side branch, the microcatheter can either be advanced over the guidewire, or replaced with a different catheter, as shown in <FIG>.

One advantage of the catheter <NUM> described in the present disclosure is that the configuration can be constructed to maintain the outer dimensions of a microcatheter, and will have a lower risk of causing harm to the artery or the subintimal space when used in the coronary arteries. That is, the deflection member <NUM> and other components of the catheter <NUM> described in the present disclosure are located within the catheter shaft <NUM>, and the dimensions of these components can thus be sized so as not to exceed the microcatheter outer diameter. The ability of the catheter <NUM> to direct the guidewire out of the distal tip also allows for the catheter <NUM> to be advanced across a lesion without requiring the catheter <NUM> to be replaced.

The catheter <NUM> described in the present disclosure can enable cardiologists to successfully perform percutaneous coronary interventions for complex chronic total occlusions. The catheter <NUM> can allow for an alternative method for directing a guidewire from the subintimal space into the true lumen that can reduce procedural costs and have a lower risk of complications as compared to current devices. Another advantage is that because the catheter <NUM> stays in place throughout the subintimal entry, little to no blood will track through the subintimal plane of tissue, which can otherwise occur when the a device (e.g., the CrossBoss described above] is removed and replaced with another device (e.g., the Stingray described above]. As a result, the subintimal space will be prevented from filling up with blood and compressing the true lumen. In turn, the subintimal entry is made easier because the true lumen beyond the CTO is maintained. If the true lumen is compressed by blood tracking in the subintimal space, the distal lumen may become very difficult to visualize.

Claim 1:
A catheter (<NUM>) comprising:
a catheter shaft (<NUM>) having a tubular wall that extends from a proximal end (<NUM>) to a distal end (<NUM>) along a longitudinal axis (<NUM>) to define a lumen (<NUM>), the tubular wall having formed therein an inner lumen (<NUM>) that extends from the proximal end to the distal end of the catheter shaft;
a deflection member (<NUM>) coupled to the distal end of the catheter shaft and in fluid communication with the inner lumen such that fluid provided to the inner lumen causes the deflection member to expand from a first volume to a second volume that is larger than the first volume;
wherein when the deflection member is in the second volume it extends from a surface of the tubular wall towards the longitudinal axis of the catheter shaft to provide a surface for deflecting an interventional device extending through the lumen and outward from the distal end of the catheter shaft at a deflection angle; and
wherein the distal end of the tubular wall includes an angled surface (<NUM>) that is angled from an outer surface of the tubular wall proximally towards an inner surface of the tubular wall.