Patent Description:
A chronic total occlusion in a coronary artery, peripheral artery, vein, dialysis fistula or other types of vasculature represents a challenge for percutaneous treatment. Percutaneous treatments are generally preferred revascularization options as compared to bypass surgery. Continuing improvements in equipment specifically developed for chronic total occlusions have allowed success rates to improve. Although the success rates for these types of procedures have improved, the procedures for percutaneous treatments still suffer from several drawbacks. Patients without a successful percutaneous treatment may need to undergo bypass surgery or experience continuing symptoms from the occlusions.

A major obstacle within a chronic total occlusion may often be encountered while attempting to advance a guidewire across the chronic total occlusion in a vasculature. A maximum resistance may be met at the most proximal point of the lesion, i.e. the firm, fibrous cap. While being advanced, a guidewire may tend to deflect away from the fibrous cap towards the adventitial layer, often entering a false lumen. This off-axis displacement of the guidewire often may result in a procedural failure.

Successful passage of the guidewire may also be obstructed by randomly located calcified regions of atherosclerotic plaque within the mass of the lesion. Microchannels within the obstruction may be desirable targets for the tip of the guidewire. However, these soft spots within the lesion are difficult to identify angiographically and are dispersed randomly within the matrix of the lesion.

Coronary arteries and other vasculatures tend to be non-linear conduits, often coursing over the surface of the epicardium and other tissues. The success of current technology is limited by this type of geometry. In current systems, a guidewire or currently available catheter is advanced down a vasculature to the level of the obstruction. At the point of the obstruction, the guidewire advancem ent may tend to proceed along the outer, greater curvature of the vasculature. Even a guidewire centered within the vasculature at the proximal edge of the chronic total occlusion may tend to proceed toward the outer, greater curvature of a vasculature.

As a result, only a minor portion of the surface area of the obstruction may be encountered with sufficient force to allow passage of the guidewire. On many occasions, the angle of encounter and/or the force applied to the fibrous cap may not be sufficient for crossing the fibrous cap with the guidewire. If the tip of the guidewire is curved prior to placement through the support catheter, direct longitudinal force may be compromised as the wire is advanced off axis. If a rapid exchange catheter system is used as catheter support, the guidewire may buckle within the guide-catheter resulting in suboptimal longitudinal guidewire force.

At times, a single lumen angioplasty balloon may be inflated just proximal to the chronic total occlusion in an attempt to center the guidewire in the vessel lumen and provide additional support for the guidewire. Atherosclerotic lesions tend to be asymmetric with an eccentric true lumen. Therefore, attempts to limit the guidewire to the central axis of the vessel lumen may result in lower rates of procedural success.

Generally, needs exist for improved apparatus and methods for treating vasculatures. More specifically, needs exist for improved apparatus and methods for efficiently and effectively passing a guidewire through a chronic total occlusion in a vasculature.

<CIT> relates to a steerable distal support system for accessing stenosis, partial occlusions, or complete occlusions within a body lumen. The steerable distal support system generally includes an elongate member that comprises a proximal portion, a more flexible intermediate portion and a deflectable distal tip. The deflectable distal tip is at a distal end of the elongate body to facilitate directionality and positioning of the steerable distal support system to the target site. Optionally, an expandable centering assembly may be disposed on the steerable support assembly to center and anchor the steerable support assembly within the body lumen.

<CIT> relates to devices and methods for fabricating and deploying an implantable device within the body. The invention is particularly suitable for delivering and deploying a stent, graft or stent graft device within a vessel or tubular structure within the body, particularly where the implant site involves two or more interconnecting vessels. The delivery and deployment system utilizes a plurality of strings which are releasably attached to the luminal ends of the implantable device.

Embodiments of the present invention solve many of the problems and/or overcome many of the drawbacks and disadvantages of the prior art by providing an apparatus for treating vasculatures.

The present disclosure includes an apparatus for efficiently and effectively passing a guidewire through a chronic total occlusion in a vasculature.

The apparatus may have a flexible shaft, one or more guidewire lumens passing longitudinally through the shaft, and a positioning means for positioning distal ends of the one or more guidewires relative to an inner wall of an external lumen.

The positioning means may be an expansible scaffold initially in a non-expanded state. A retractable sheath may surround the expansible scaffold and the retractable sheath may be retracted for expanding the expansible scaffold.

The positioning means may also be one or more balloons where the one or more balloons are inflated through an inflation port running longitudinally in the shaft. The positioning means may also include guidewire lumens coupled to or otherwise disposed within the expansible scaffold. The positioning means may also include inflatable means surrounding distal ends of the guidewire lumens. The inflatable means may or may not be located within an expansible scaffold.

The positioning means may also be a rotatable core within the shaft. The positioning means may also include a deflectable tip on the catheter. The positioning means may also include a shape-memory material integrated with the guidewire lumens.

A method of operating a catheter apparatus (not claimed) may include providing a catheter apparatus including a flexible shaft, one or more guidewire lumens passing longitudinally through the shaft, one or more guidewires within the one or more guidewire lumens, and a positioning means, inserting a guide catheter into a vasculature with a chronic total occlusion, inserting the catheter apparatus into the guide catheter, activating the positioning means for positioning the one or more guidewires relative to the chronic total occlusion, and advancing the one or more guidewires through the one or more guidewire lumens and into contact with the chronic total occlusion.

The one or more guidewires may be passed through the chronic total occlusion. The catheter apparatus may be withdrawn from the vasculature while leaving the one or more guidewires in place. The one or more guidewires may be withdrawn from contact with the chronic total occlusion and the one or more guidewires may be advanced through the one or more guidewire lumens into contact with the chronic total occlusion repeatedly until a suitable site for passing the one or more guidewires through the chronic total occlusion is found. The positioning means may be activated before each advancing the one or more guidewires through the one or more guidewire lumens into contact with the chronic total occlusion.

The present disclosure further includes a catheter apparatus including a multi-lumen main shaft; one or more guidewire lumens extending from a distal end of the multi-lumen shaft with lumens within the one or more guidewire lumens contiguous with at least one of the multi-lumens of the multi-lumen main shaft; an expansible support structure coupled to the distal end of the multi-lumen shaft; one or more loops corresponding to each of the one or more guidewire lumens, wherein the one or more loops corresponding to each of the one or more guidewire lumens are coupled to the expansible support structure, and wherein the one or more loops corresponding to each of the one or more guidewire lumens project inward from the plane of the expansible support structure; and wherein the one or more guidewire lumens are threaded through the corresponding one or more loops.

Additional features and advantages are set forth or apparent from consideration of the following detailed description, drawings and claims.

Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate examples of the disclosure and together with the detailed description serve to explain the principles of the disclosure. In the drawings:.

Examples of the present disclosure may include apparatus and methods for advancing one or more guidewires through chronic total occlusions in vasculatures.

Examples of the present disclosure may incorporate several features to successfully pass one or more guidewires through a chronic total occlusion. Features of the present disclosure may include multiple lumens constructed within a catheter shaft, expansion or activation of a distal tip of a catheter apparatus for creating a scaffold effect, and/or decentralization of the guidewire lumens after activation or distal catheter repositioning for allowing multiple sections of a fibrous cap to be forcefully engaged by a guidewire. Examples of the present disclosure may optimize advancement of the one or more guidewires into multiple sections of a fibrous cap of a chronic total occlusion with reasonable force.

In examples of the present disclosure one or more over-the-wire lumens may be constructed within a shaft of a catheter apparatus. Examples of the present disclosure may preferably use two or more lumens. Larger vasculatures, such as coronary arteries, may accommodate higher profile catheters and allow use of additional lumens. Each lumen may accommodate at least a <NUM>" diameter guidewire. Other sized lumens and guidewires may be accommodated based upon the desired end use. Standard off-the-shelf or customized guidewires may be used. For example, in addition to traditional guidewires, examples of the present disclosure may be used with guidewires including, but not limited to, steerable, hydrophilic, Teflon-coated, heparin-coated, ball-tip, J -tip, spiral tip, angulated wire and others.

Examples of the present disclosure may be combined with other types of catheter devices. The positioning systems and methods of the present disclosure may be to deliver and/or direct other catheters towards a desired position. For example, a vibrating catheter or other specialized catheter may be directed towards a chronic total occlusion or other location in a vasculature. A microcatheter with a distal positioning device, including, for example, one or more balloons that may be inflated individually, sequentially or simultaneously, or other features, may be placed in proximity to a chronic total occlusion. A positioning system may steer the microcatheter away from a wall of a vessel, as it probes a cap of a chronic total occlusion. Microcatheters with angulation or other features may be placed in proximity to a chronic total occlusion where the angulation steers away from a wall of a vessel, probes a cap of a chronic total occlusion or otherwise changes directions. A catheter portion and/or sheath of examples of the present disclosure may be large enough to deliver and/or position specialized catheters to a desired location. Positioning devices may then be used to position the specialized catheters in a beneficial manner for a procedure.

In particular, examples of the present disclosure may deliver energy via the guidewires through radio frequencies and/or lasers. Furthermore, other types of energy may be delivered such as direct conductive heat energy, infrared or other types of energy that may be useful in particular applications. Various types of guidewires and/or delivering energy via guidewires may allow for various types of treatments. The external diameter of a catheter apparatus of the present disclosure may allow passage through a standard guide catheter. The outer surface of a catheter apparatus of the present disclosure may be coated with hydrophilic material to allow easier passage through the guide catheter. With alternate dimensions, the catheter apparatus of the present disclosure may be used in peripheral vessels. In this situation, a guide catheter may not be necessary to insert the device into the vasculature.

IA - IK show a self-expanding catheter apparatus <NUM>. The external diameter of the self-expanding catheter apparatus <NUM> may pass through a sheath <NUM>.

The sheath <NUM> may be a separate element surrounding the distal end of the catheter apparatus <NUM> to maintain the catheter apparatus <NUM> in an inactive state. The sheath <NUM> may have a rounded or tapered end for facilitating passage through a vasculature. Other end configurations are possible depending on particular uses.

Additional examples of the sheath may be shown in Figs. A sheath <NUM>, <NUM> may be used to lower a profile of a self-expanding distal portion <NUM> of the catheter apparatus <NUM>, which may preferably be a nitinol component, during insertion and removal of the catheter apparatus <NUM> from a vasculature. A sheath <NUM> may have a shorter configuration, as shown in Fig. IJ, covering at least a distal self-expanding component, preferably a nitinol element, on the catheter apparatus <NUM>. The sheath <NUM>, however, may preferably be long enough to correspond to the length of the treated vasculature, i.e., long enough to cover the portion of the catheter extending outside of a guide catheter and into the vasculature. This sheath configuration may function by insertion through a guide catheter and advancement into a treated vasculature. The sheath <NUM> may be attached <NUM> to a solid core guidewire and/or flexible device <NUM>. The solid core guidewire and/or flexible device <NUM> may be long enough to traverse a guide catheter. The solid core guidewire and/or flexible device <NUM> may be a solid structure with no internal lumens and may preferably be made of plastic or similar materials. The solid core guidewire and/or flexible device <NUM> may be manipulated from outside the body, preferably by means of an expanded element <NUM> at a proximal end of the solid core guidewire and/or flexible device <NUM>. The solid core element <NUM> may parallel the catheter apparatus <NUM> through a guide catheter. A distal portion <NUM> of the sheath <NUM> may be flared to fit a self-expanding portion <NUM> of the catheter apparatus device <NUM>. The distal portion <NUM> may also have one or more radiopaque or other types of markers <NUM>. The sheath <NUM> may have a stop point to allow withdrawal of the sheath <NUM> to a predetermined position, which may also facilitate resheathing of the catheter apparatus <NUM>.

Alternatively, as shown in Fig. IK, a sheath <NUM> may have a longer length, completely surrounding an intravascular portion of the catheter apparatus <NUM> during insertion and removal. The sheath <NUM> may be a flexible with a roughly cylindrical shape. The sheath <NUM> may preferably be made of plastic or other similar materials. This sheath configuration may have a larger profile element <NUM> at an extra-vascular, proximal end, allowing for easier handling and movement of the sheath <NUM>. A distal portion <NUM> of the sheath <NUM> may be flared to fit a self-expanding portion <NUM> of the catheter apparatus device <NUM>. The distal portion <NUM> may also have one or more radiopaque or other types of markers <NUM>. The sheath <NUM> may have a stop point to allow withdrawal of the sheath <NUM> to a predetermined position, which may also facilitate resheathing of the catheter apparatus <NUM>. The sheath <NUM> may be used in conjunction with a guide catheter or may function without a guide catheter in a non-coronary vasculature.

A body or shaft <NUM> of the catheter apparatus <NUM> may be made of a flexible plastic material or any other similar substance. A hydrophilic coating may or may not be added to the outer surfaces of the catheter apparatus <NUM>. One or more hubs <NUM> corresponding to one or more guidewires <NUM> and one or more lumens <NUM> may be disposed at a proximate end <NUM> of the catheter apparatus <NUM>.

The one or more hubs <NUM> may be marked, color-coded, numbered or may otherwise differentiate between one another. Identification of individual guidewire lumens may allow more effective use of examples of the present disclosure. With marking, users may improve their ability to identify which guidewire lumen may be preferably used during a procedure. For example, if a particular guidewire lumen is in a preferable location relative to other guidewire lumens an operator may desire a quick and reliable method of inserting a guidewire through that particular guidewire lumen. Marking may save time and effort by eliminating trial and error to determine a desired guidewire lumen. Alternatively, marking may be useful for applications other than treatment of occluded vasculatures, such as steering guidewires through vasculatures via various lumens. For example, marking can allow examples of the present disclosure to be used in other areas and/or conditions of a vasculature, such as traversing the tortuous coronary arteries. Distal and proximal ends of the guidewire lumens may be similarly marked to identify the guidewire lumens. Distal ends or structures on distal ends of the guidewire lumens may be marked such that the user may identify a preferred guidewire lumen while the catheter apparatus is within a patient. Marking with radiopaque or other types of markers may include temporary structures within the guidewire lumens. For example, markers may be present on stylets within the guidewire lumens. The stylets may be removed if desired to reduce mass or otherwise improve efficiency of a procedure.

The one or more hubs <NUM> may allow introduction of stylets or other structures that run through the catheter apparatus to render it stiff or to remove debris from its lumen. The one or more hubs <NUM> may also allow passage of one or more guidewires <NUM>.

Generally, a distal portion <NUM> of the catheter apparatus <NUM> may function as a scaffold-type structure. The distal portion <NUM> of the catheter apparatus <NUM> may stabilize the catheter apparatus <NUM> within a vasculature lumen as one or more guidewires <NUM> are advanced into a chronic total occlusion. One or more guidewires <NUM> may be threaded through one or more lumens <NUM> within the catheter apparatus <NUM>.

The distal portion <NUM> of the catheter apparatus <NUM> is preferably self-expanding. <FIG> shows the distal end <NUM> of the catheter apparatus <NUM> in an expanded state. <FIG> shows a cross section of the catheter apparatus <NUM> with a retractable sheath <NUM> surrounding the body <NUM>. The retractable sheath <NUM> may be retracted by moving the retractable sheath towards the proximate end <NUM> of the catheter apparatus <NUM>. The distal portion <NUM> of the catheter apparatus <NUM> may include an activated scaffold structure <NUM> to stabilize the catheter apparatus <NUM>. The activated scaffold structure <NUM> may expand to match a diameter of the vasculature lumen upon retraction of the retractable sheath <NUM>.

Nitinol and/or stainless steel may be incorporated into the scaffold structure <NUM>. Nitinol is an illustrative example of a shape memory alloy. Other shape memory alloys or other similar substances may be used. Generally, after a sample of a shape memory alloy has been deformed from its original crystallographic configuration, the shape memory alloy regains its original geometry by itself. This property of shape memory alloys may allow for expansion of the scaffold structure <NUM> after retraction of the retractable sheath <NUM>. The nitinol and/or stainless steel scaffold structure <NUM> may create a stent-like mesh. The scaffold structure <NUM> may form the surface of the distal portion <NUM> of the catheter apparatus <NUM>.

<FIG> shows an inactive scaffold structure <NUM>. The inactive scaffold structure <NUM> may be advanced over a guidewire into a chronic total occlusion with a retractable sheath <NUM> in place to constrain the self-expanding but inactive scaffold structure <NUM>. The retractable sheath <NUM> may cover the inactive scaffold structure <NUM>. When the inactive scaffold structure <NUM> is properly positioned, the retractable sheath <NUM> may be retracted by an appropriate retraction means. As the retractable sheath <NUM> is retracted, the inactive scaffold structure <NUM> of the catheter apparatus <NUM> may become active and may flare out. During a flare out process, the inactive scaffold structure <NUM> may self-expand to assume a larger diameter to roughly approximate the diameter of the vasculature in the location of the distal portion <NUM> of the catheter apparatus <NUM>.

The retraction of the retractable sheath <NUM> may be a continuous or step-wise process. For example, the retractable sheath <NUM> may be retracted in one operation by a user until the scaffold structure <NUM> is fully exposed. Alternatively, the retractable sheath <NUM> may be retracted in increments less than that required for full expansion of the scaffold structure <NUM>. Stop points during retraction of the retractable sheath <NUM> may allow for predetermined quantities of expansion of the scaffold structure <NUM>. For example, if a procedure required less than full expansion of the scaffold structure <NUM>, a stop point short of full retraction of the retractable sheath <NUM> may be chosen.

The conversion and expansion of the inactive scaffold structure <NUM> into an active scaffold structure <NUM> may create a relatively stable platform from which to advance the one or more guidewires <NUM> into multiple sections of the chronic total occlusion. The activated catheter apparatus <NUM> with the retractable sheath <NUM> retracted may have an activated scaffold structure shaped as a truncated cone or other suitable shape. A surface <NUM> of the expanded distal end <NUM> of the catheter apparatus <NUM> may consist of a "skin" of the scaffold structure <NUM>. An end cap <NUM> may or may not cover the distal end <NUM> of the catheter apparatus <NUM>. The end cap <NUM> may preferably be made of an impervious expandable polymer, but other similar substances may be used.

<FIG> shows an activated scaffold structure <NUM> that may be filled with an expandable polymer or similar material. The expandable polymer or similar material may fill the scaffold structure <NUM> to form a truncated, conical or other appropriate shape for securing the catheter apparatus <NUM> within the vasculature lumen. The expandable polymer may support distal portions of one or more guidewire lumens <NUM>. Upon expansion of the expandable polymer, the embedded lumen ends <NUM> may flare out correspondingly with the end cap <NUM>. <FIG> shows a cross section of the catheter apparatus <NUM> with the retractable sheath <NUM> surrounding the shaft <NUM>. <FIG> shows an end view of the expanded end cap <NUM> with embedded guidewire lumens <NUM>.

A skin <NUM> may surround the expandable polymer or similar material. The skin <NUM> may be a temporary metal "stent". The metal stent may be a mesh type structure. The metal stent may become a truncated conical shape after expansion or any other suitable shapes.

The a - b dimension <NUM> indicated in <FIG> may shorten when the retractable sheath <NUM> is removed from scaffold structure <NUM>. The degree of shortening of the a - b dimension <NUM> may vary depending on the degree of expansion, the materials used, etc..

The retractable sheath <NUM> may be retracted to a stop point. The stop point may prevent over-retraction of the retractable sheath <NUM>. A retractable sheath <NUM> at the stop point may facilitate re-sheathing of the scaffold structure <NUM>.

<FIG> shows multiple guidewire lumens <NUM> that may be suspended within a scaffold structure <NUM> without using an expansible polymer or similar filler. A skin <NUM> may be made of nitinol, stainless steel, or another expansible substance. The one or more guidewire lumens <NUM> may extend to the distal end <NUM> of the scaffold structure <NUM>. The scaffold structure <NUM> may begin roughly at a transition point <NUM>. The one or more guidewire lumens <NUM> may or may not be embedded in an end cap <NUM>. The end cap may an impervious plastic material.

<FIG> shows a catheter apparatus with an expandable skin <NUM> and a deflectable tip <NUM> according to the present invention. The deflectable tip <NUM> may be rotatable or otherwise moveable. The deflectable tip <NUM> may be rotatable with a rotator <NUM> or other similar device at the proximate end <NUM> of the catheter apparatus <NUM>. The example depicted in <FIG> preferably does not include and end cap <NUM>. The lack of an end cap <NUM> may allow for freedom of movement of the deflectable tip <NUM>. The distal portion <NUM> of the catheter apparatus <NUM> may flare after the retractable sheath <NUM> is retracted. A single, centrally located deflectable lumen <NUM> may allow a guidewire <NUM> to be advanced in numerous planes. The deflectable tip <NUM> may allow for controlled probing of the fibrous cap of a chronic total occlusion.

Other examples of the present disclosure may include one or more balloons at or near a distal end of a catheter apparatus. The one or more balloons may be circumferential. Alternatively, the one or more balloons may be offset and placed longitudinally. Other positions and arrangements are possible depending on particular situations.

<FIG> (and the following figures which are presented for illustration purposes only), shows an example of the present disclosure with a balloon <NUM> that may be placed longitudinally near a distal tip <NUM> of a catheter apparatus <NUM>. The balloon <NUM> may be parallel the long axis of a shaft <NUM> of the catheter apparatus <NUM>. Inflation of the balloon <NUM> may deflect the position of one or more guidewire lumens <NUM> relative to the fibrous cap of a chronic total occlusion. The balloon <NUM> may be inflated to a diameter that may buttress the catheter apparatus <NUM> against a wall of the vasculature lumen. The balloon <NUM> may then be deflated, the catheter apparatus <NUM> rotated, and the balloon <NUM> reinflated.

<FIG> shows a cross section of the catheter apparatus <NUM>. The balloon <NUM> may be inflated and deflated through an inflation port <NUM>. The inflation port <NUM> may pass through the shaft <NUM> to connect the balloon <NUM> to a proximate end <NUM> of the catheter apparatus <NUM>. This method may result in one or more guidewires <NUM> probing various sections of the fibrous cap. One or more hubs <NUM> at the proximate end <NUM> of the catheter apparatus <NUM> may allow passage of the one or more guidewires <NUM>. Stylets or other similar structures may be inserted or reinserted into the catheter apparatus <NUM> to facilitate rotation.

<FIG> shows an example of the present disclosure with a first longitudinal balloon <NUM> and a second longitudinal balloon <NUM> positioned near a distal end <NUM> of a catheter apparatus <NUM>. More balloons may be used for additional or different control of the catheter apparatus. The multiple balloons <NUM>, <NUM> may be inflated individually, simultaneously, alternatively or sequentially depending on the particular circumstances. The pattern of inflation and/or deflation of the multiple balloons <NUM>, <NUM> may allow redirection of a distal catheter tip <NUM> relative to a fibrous cap of a chronic total occlusion. Repositioning of the distal catheter tip <NUM> may permit more complete interrogation of the fibrous cap with one or more guidewires <NUM>. One or more hubs <NUM> at the proximate end <NUM> of the catheter apparatus <NUM> may allow passage of the one or more guidewires <NUM> through a shaft <NUM>.

<FIG> shows a cross section of the catheter apparatus <NUM>. One or more guidewire lumens <NUM> may pass through the catheter apparatus <NUM>. Examples of the present disclosure may be constructed with multiple inflation ports (not shown) or with one inflation port <NUM> servicing the multiple balloons <NUM>, <NUM>. If the later option is utilized, the balloon materials may be constructed to allow selective, and/or sequential inflations at increasing balloon pressures. The balloons <NUM>, <NUM> may be positioned at various angles relative to one another around the circumference of the shaft <NUM>.

<FIG> shows an example of the present disclosure with a balloon <NUM> with a distal surface <NUM> in a catheter apparatus <NUM>. The balloon <NUM> may be flat, cylindrical or any other suitable configuration. Additionally, the balloon <NUM> may be sectioned. One or more guidewire lumens <NUM> may be extruded through the balloon material. The balloon <NUM> may be inflated to match the inner diameter of the vasculature lumen. <FIG> shows an end view of the catheter apparatus <NUM>. As the balloon <NUM> expands, the one or more guidewire lumens <NUM> extruded through the balloon <NUM> may diverge relative to one another in reaction to expansion of the balloon <NUM>. The divergence may allow one or more guidewires <NUM> to probe various sections of the fibrous cap of the chronic total occlusion. One or more hubs <NUM> at the proximate end <NUM> of the catheter apparatus <NUM> may allow passage of the one or more guidewires <NUM>. <FIG> shows a cross section of the catheter apparatus <NUM>. A balloon inflation port <NUM> may pass through a shaft <NUM> with the one or more lumens <NUM> to inflate and/or deflate the balloon <NUM>.

<FIG> shows a catheter apparatus <NUM> with an inner core <NUM> within an outer core <NUM>. The inner core <NUM> may contain one or more lumens <NUM>. Examples of the present disclosure may preferably include two or more lumens <NUM>. <FIG> illustrates an example with two lumens placed at positions of <NUM> o'clock and <NUM> o'clock within the inner core <NUM>. Other quantities of lumens <NUM> and positions are contemplated for various applications and situations. The inner core <NUM> may be rotated within the outer shell <NUM> of the catheter apparatus <NUM> by turning or otherwise manipulating a rotator <NUM> at a proximate end <NUM> of the catheter apparatus <NUM>. The rotator <NUM> may be coupled <NUM> or otherwise connected to the inner core <NUM>. One or more guidewires <NUM> may be connected to one or more hubs <NUM> at the proximate end <NUM> of the catheter apparatus <NUM>. The one or more guidewires may extend from a distal end <NUM> of the catheter apparatus <NUM>.

A rotatable inner core <NUM> of catheter apparatus <NUM> may be used in conjunction with the various balloon configurations described above. For example, if constructed with a non-longitudinal stabilizing balloon, the shape of the distal tip balloon may be circumferential, i.e., doughnut-shaped.

<FIG> shows an example of the present disclosure with a single stabilizing balloon <NUM> and a deflecting tip <NUM> on a catheter apparatus <NUM>. The single stabilizing balloon <NUM> may be used in conjunction with a deflectable distal catheter tip <NUM> for eccentric placement of one or more guidewires <NUM>. The one or more guidewires <NUM> may be passed through one or more hubs <NUM> at a proximate end <NUM> of the catheter apparatus <NUM>. <FIG> shows a cross section of the catheter apparatus <NUM>. One or more lumens <NUM> may pass through a shaft <NUM>. An inflation port <NUM> may allow inflation and/or deflation of the stabilizing balloon <NUM>. The deflecting tip <NUM> may be located at various angles depending on the particular situation.

Catheter apparatus shafts <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> may be constructed with either a circular, oval or rectangular shape. Other shapes are possible depending on particular uses.

<FIG> shows an example of the present disclosure with an expansible portion <NUM> at a distal tip <NUM> of a catheter apparatus <NUM>. The expansible portion <NUM> may be a mesh or other similar configuration as described above. The expansible portion <NUM> may be expanded by retracting a retracting sheath <NUM> away from the distal tip <NUM> of the catheter apparatus <NUM>. The expansible portion <NUM> may be expanded into contact with a wall of a vasculature.

<FIG> shows a detail of the catheter apparatus <NUM>. A central core <NUM> may contain one or more guidewire lumens <NUM>. The central core <NUM> may or may not be expandable. The central core <NUM> may be rotatable to allow one or more guidewires <NUM> to probe various sections of a fibrous cap. One or more hubs <NUM> at the proximate end <NUM> of the catheter apparatus <NUM> may allow passage of the one or more guidewires <NUM>.

<FIG> shows an example of the present disclosure with an expansible portion <NUM> at a distal tip <NUM> of a catheter apparatus <NUM>. The expansible portion <NUM> may be a mesh or other similar configuration as described above. The expansible portion <NUM> may be expanded by retracting a retracting sheath <NUM> away from the distal tip <NUM> of the catheter apparatus <NUM>. The expansible portion <NUM> may be expanded into contact with a wall of a vasculature. One or more hubs <NUM> at the proximate end <NUM> of the catheter apparatus <NUM> may allow passage of the one or more guidewires <NUM>.

<FIG> shows a detail of the catheter apparatus <NUM>. One or more guidewire lumens <NUM> may be formed of extruded plastic or similar materials. The figures generally illustrate three guidewire lumens <NUM>, but other numbers and configurations may be desirable depending on particular uses. The one or more guidewire lumens <NUM> may have shape-memory alloys or other similar materials integrated into, surrounding or within the structure of the one or more guidewire lumens <NUM>. Preferably, the one or more guidewire lumens <NUM> may self-expand upon retraction of the retraction sheath <NUM> such that ends <NUM> of the one or more guidewire lumens are spaced apart and approximately halfway between the center point and the inner surface of a vasculature. The one or more guidewire lumens <NUM> may be configured to expand into various predetermined positions and configurations depending on particular applications. For example, <FIG> shows a triangular configuration for the guidewire lumens <NUM>. Other configurations are possible using three guidewire lumens <NUM>. Furthermore, different numbers of guidewire lumens may be used in various configurations.

Alternatively, the one or more guidewire lumens <NUM> may be coupled to an inner surface of the expansible portion <NUM>. The one or more guidewire lumens <NUM> may be adhered or integrally molded to the inner surface of the expansible portion <NUM>.

Expansion of the expansible portion <NUM> may cause the one or more guidewire lumens <NUM> to separate via a self-expanding shape-memory material. Alternatively, the one or more guidewire lumens <NUM> may not be coupled to the expansible portion <NUM> but may instead be positioned within the internal volume of the expansible section <NUM> to allow probing of a fibrous cap. Additionally, a self-expanding polymer may fill the expansible portion <NUM>. In an initial configuration the self-expanding polymer may be in a compressed state. As the expansible portion <NUM> is released from the retracting sheath <NUM>, the self-expanding polymer may expand as well. The one or more guidewire lumens <NUM> may be embedded in the self-expanding polymer and may be moved into a desired position by the expansion of the self-expanding polymer. The self-expanding polymer may expand by absorbing moisture or blood from within the vasculature or through other expansion mechanisms. The self-expanding polymer may then be removed after a procedure.

<FIG> illustrates the operation of the catheter apparatus <NUM> of <FIG> and <FIG>. Similar operational procedures may be used for other examples described herein. Step <NUM> of <FIG> shows the catheter apparatus <NUM> in an initial state with a retractable outside sheath <NUM> moved as far as possible distally from a guidewire lumen tube <NUM>. Steps <NUM> - <NUM> show incremental stages of retraction of the retractable outside sheath <NUM>. As the retractable outside sheath <NUM> is retracted back over the guidewire lumen tube <NUM>, the expansible portion <NUM> is incrementally exposed and allowed to expand. As the expansible portion <NUM> expands the one or more guidewire lumens <NUM> separate and are held in a desired position by the shape-memory allow materials or by coupling to the expansible portion <NUM>. Step <NUM> shows the expansible portion <NUM> in a fully deployed state. The end view of <FIG> shows the one or more guidewire lumens <NUM> in the fully deployed state. Step <NUM> shows a guidewire <NUM> inserted through a guidewire lumen <NUM>. <FIG> illustrates the operation of the catheter apparatus <NUM> as shown in <FIG> within a vasculature <NUM> with an occlusion <NUM>.

<FIG> shows an example of the present disclosure with one or more inflatable devices <NUM> surrounding one or more guidewire lumens <NUM> within an expansible portion <NUM> of a catheter apparatus <NUM>. The expansible portion <NUM> may be a mesh or other similar configuration as described above. The expansible portion <NUM> may be expanded by retracting a retracting sheath <NUM> away from a distal tip <NUM> of the catheter apparatus <NUM>. The expansible portion <NUM> may be expanded into contact with a wall of a vasculature. The expansible portion <NUM> may be omitted as shown in <FIG>.

The inflatable devices <NUM> may initially be in a deflated condition during insertion and positioning of the catheter. The inflatable devices <NUM> preferably are balloons, but may be any other expansible type of device. The balloons may surround the outer surface of the one or more guidewire lumens <NUM>. The balloons may be cylindrical or other shapes to position the one or more guidewire lumens <NUM> within the expansible portion <NUM>. The inflatable devices <NUM> may include one balloon for each guidewire lumen <NUM> or one balloon may correspond to several guidewire lumens <NUM>. For example, a single inflatable device <NUM> may be inflated to separate all of the guidewire lumens <NUM>. Alternatively, two separate inflatable devices <NUM> may be used to separate three or more guidewire lumens. The inflatable devices <NUM> may be bifurcated or trifurcated depending on the number of guidewire lumens <NUM> and the particular application. The expansible sheath <NUM> may assist in containing multiple, separate inflatable devices <NUM>, but may not be essential to the operation of the present disclosure.

One or more ports (not shown) may allow inflation or one or more of the inflatable devices <NUM> depending on the number of separate inflatable devices <NUM>. For example, one port may be used to inflate one inflatable device <NUM>. Alternatively, if two or more separate inflatable devices <NUM> are present, then two or more ports may be used to inflate and deflate the inflatable devices <NUM> serially or in parallel depending on a particular use or condition. Different numbers and combinations of inflatable devices and ports may be possible. Inflation of various combinations of inflatable devices <NUM> with various numbers and configurations of ports may allow for probing of a fibrous cap. If ends of the one or more guidewire lumens <NUM> or the inflatable devices <NUM> themselves are marked, a user may inflate specific inflatable devices <NUM> but not others to more accurately interrogate an occlusion. Each of the inflatable devices <NUM> may be inflated into contact with the expanded expansible portion <NUM> to secure the position of the one or more guidewire lumens <NUM>. Guidewires (not shown) may then be passed through the one or more guidewire lumens <NUM>. The inflatable devices <NUM> may be deflated prior to withdrawing the catheter apparatus <NUM>.

As shown in <FIG> an example of the present disclosure may include the inflatable devices <NUM> without the expansible portion <NUM>, as shown in <FIG>. The inflatable devices <NUM> may be exposed by withdrawing the retracting sheath <NUM>. Particularly if the inflatable devices <NUM> are unitary, the expansible portion <NUM> may not be needed. However, even if the inflatable devices <NUM> are separate the expansible portion <NUM> may be omitted.

Step <NUM> of <FIG> shows the catheter apparatus <NUM> in an initial state with a retractable outside sheath <NUM> moved as far as possible distally from a guidewire lumen tube <NUM>. Steps <NUM> - <NUM> show incremental stages of retraction of the retractable outside sheath <NUM> to expose the one or more guidewire lumens <NUM> with corresponding inflatable devices <NUM>. Steps <NUM> - <NUM> show incremental stages of inflation of the inflatable devices <NUM> into a final position with a vasculature <NUM> with an occlusion <NUM>. Step <NUM> shows the catheter apparatus <NUM> in a fully deployed state. Step <NUM> shows a guidewire <NUM> inserted through a guidewire lumen <NUM>.

<FIG> illustrates operation of a catheter apparatus <NUM> that may include shape-memory materials integrated with the one or more guidewire lumens <NUM>. Preferably, the one or more guidewire lumens <NUM> may be constructed out of extruded plastic or other similar materials. Shape-memory or other expansible materials may be integrated into, surround, be contained within or reinforce the one or more guidewire lumens <NUM>.

Step <NUM> of <FIG> shows the catheter apparatus <NUM> in an initial state with a retractable outside sheath <NUM> moved as far as possible distally from a guidewire lumen tube <NUM>. The one or more guidewire lumens <NUM> may be exposed by withdrawing the retracting sheath <NUM> from the distal end of a catheter apparatus <NUM> as shown in Steps <NUM> - <NUM>. The one or more guidewire lumens <NUM> may then assume a final spaced or relaxed configuration as shown in Step <NUM>. The guidewire lumens may move outward relative to one another a desired distance and/or into contact with inner walls of a vasculature <NUM> with an occlusion <NUM>. A guidewire <NUM> may then be threaded through the one or more guidewire lumens <NUM> as shown in Step <NUM>. After completion of a procedure, the retracting sheath <NUM> may be advanced towards the distal end of the catheter apparatus to compress the one or more guidewire lumens <NUM> into a compact arrangement for removal from the vasculature <NUM>. Alternatively, the one or more guidewire lumens <NUM> may be withdrawn into the distal end of the retracting sheath <NUM> before removal from the vasculature <NUM>.

<FIG> illustrates operation of a catheter apparatus <NUM> with expansible devices <NUM> surrounding one or more guidewire lumens <NUM>. Preferably, the expansible devices <NUM> are sponges or other materials that expand within the vasculature without input from a user. Each guidewire lumen <NUM> may have a separate expansible device <NUM> or multiple guidewire lumens may be incorporated into one expansible device <NUM>.

Step <NUM> of <FIG> shows the catheter apparatus <NUM> in an initial state with a retractable outside sheath <NUM> moved as far as possible distally from a guidewire lumen tube <NUM>. The one or more guidewire lumens <NUM> may be exposed by withdrawing the retracting sheath <NUM> from the distal end of a catheter apparatus <NUM> as shown in Steps <NUM> - <NUM>. As the retracting sheath <NUM> is withdrawn from the expansible devices <NUM>, the expansible devices <NUM> begin to expand. If the expansible devices <NUM> are sponges, the expansible devices <NUM> may absorb moisture from the vasculature to increase in volume. The one or more guidewire lumens <NUM> may then assume a final expanded configuration as shown in Step <NUM>. The guidewire lumens <NUM> embedded with the expansible devices <NUM> may move outward relative to one another a desired distance and/or into contact with inner walls of a vasculature <NUM> with an occlusion <NUM>. A guidewire <NUM> may then be threaded through the one or more guidewire lumens <NUM> as shown in Step <NUM>. After completion of a procedure, the retracting sheath <NUM> may be advanced towards the distal end of the catheter apparatus <NUM> to compress the one or more guidewire lumens <NUM> into a compact arrangement for removal from the vasculature <NUM>. Alternatively, the one or more guidewire lumens <NUM> may be withdrawn into the distal end of the retracting sheath <NUM> before removal from the vasculature <NUM>. Movement of the retracting sheath <NUM> may compress the expansible devices <NUM> into a position suitable for removal from the vasculature <NUM>. If the expansible devices <NUM> are sponges, the compression may force moisture out of the sponges.

Generally, after crossing a chronic total occlusion with a guidewire, the catheter apparatus may be resheathed and removed from the vasculature. The guidewire may be left in position.

One or more guidewires preferably remain in or near the longitudinal axis of the corresponding support catheter lumen. This positioning of the one or more guidewires may optimize the force of the one or more guidewires when engaged with the fibrous cap of the chronic total occlusion. Multiple eccentrically located guidewire lumens may improve the chance of success in passing one or more guidewires through a chronic total occlusion. The mass of the multi-lumen support catheter may provide additional support for the guidewire and prevents off- axis, i.e., lateral, displacement of portions of the one or more guidewires located in the guide catheter and in the vasculature. Eccentric distribution of the one or more guidewire lumens may allow engagement of multiple, eccentric sections of the fibrous cap. Examples of the present disclosure may permit simultaneous placement of multiple guidewires. Multiple guidewires may enhance available techniques such as "parallel guidewire" and "see-saw" wire.

<FIG> shows a catheter apparatus <NUM> with guidewire lumens <NUM>, <NUM>, <NUM> passing through loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The number and configuration of the loops or guidewire lumens <NUM>, <NUM>, <NUM> may be variable. Alternative numbers and configurations are possible. Guidewire lumens <NUM>, <NUM>, <NUM> may be guided into a predetermined position during expansion of an expansible support structure <NUM> by threading the guidewire lumens <NUM>, <NUM>, <NUM> through the inwardly projecting loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be coupled to the expansible support structure <NUM>. <FIG> illustrate an example of the present disclosure where each guidewire lumen <NUM>, <NUM>, <NUM> may pass through two loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Alternative examples may only use one loop for each guidewire lumen. Still other alternative examples may use three or more loops for each guidewire lumen. The operation of the loops and guidewire lumens in <FIG> are illustrative of the alternative examples. The guidewire lumens <NUM>, <NUM>, <NUM> are guided into position by passing through the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The expansible support structure <NUM> may be coupled to a main multi-lumen shaft <NUM> by any conventional means such as adhesive, welding, etc. In the current example of the disclosure, three guidewire lumens <NUM>, <NUM>, <NUM> are shown, but other numbers and configurations of lumens may be provided. A sheath <NUM> may hold the expansible support structure <NUM> in a compressed state prior to deployment of the expansible support structure <NUM>.

<FIG> shows a flat projection of the expansible support structure <NUM> with loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <FIG> show a five closed-cell configuration. Examples of the present disclosure may include different quantities of closed-cells depending on desired applications. <FIG> shows a first closed cell <NUM>, a first connector region <NUM>, a second closed cell <NUM>, a second connector region <NUM>, a third closed cell <NUM>, a third connector region <NUM>, a fourth closed cell <NUM>, a fourth connector region <NUM>, and a fifth closed cell <NUM>. In <FIG>, the first closed cell <NUM> may be at a distal end of the catheter apparatus <NUM> and the firth closed cell <NUM> may located towards a proximal end of the catheter apparatus <NUM>. In each closed cell, struts <NUM> may form a zigzag pattern to support the catheter apparatus <NUM>. Connectors <NUM> residing in the first connector region <NUM> may connect the first closed cell <NUM> to the second closed cell <NUM> by linking strut intersections <NUM> on the first closed cell <NUM> with strut intersections <NUM> on the second closed cell <NUM>. Connectors <NUM> may be thinner than struts <NUM> and the angular relationship between struts <NUM> and connectors <NUM> may change during expansion and compression of the expansible support structure <NUM>. Similar structures and interactions may be found in and between the remaining closed cells.

Loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be located at strut intersections <NUM>. Loops <NUM>,
<NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be coupled to the strut intersections <NUM> by loop supports <NUM>. Loop supports <NUM> may be tapered to reduce stress on the apparatus. Struts <NUM> may also be tapered to reduce stress on the apparatus. The loop supports <NUM> may be positioned at other locations along the struts <NUM> or connectors <NUM> if desired. Loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and inner shape cutouts may be circular, oval, oblong or any additional shapes to allow the guidewire lumens <NUM>, <NUM>, <NUM> to slide within the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Shapes other than circles may be beneficial when the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> lie at an angle other than perpendicular to the cylindrical plane of the expansible support structure <NUM>. Loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be shaped to correspond to guidewire lumens <NUM>, <NUM>, <NUM> and allow the guidewire lumens <NUM>, <NUM>, <NUM> to slide through the loop openings.

Each guidewire lumen <NUM>, <NUM>, <NUM> may pass through two loops in the example of <FIG>. For example, guidewire lumen <NUM> may pass through loops <NUM> and <NUM>, guidewire lumen <NUM> may pass through loops <NUM> and <NUM>, and guidewire lumen <NUM> may pass through loops <NUM> and <NUM>. Passing the guidewire lumens <NUM>, <NUM>, <NUM> through the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may position the guidewire lumens <NUM>, <NUM>, <NUM> in a desired position within the expansible support structure <NUM>. As indicated above, other numbers and configurations of loops are possible.

To prevent twisting and damage to the guidewire lumens <NUM>, <NUM>, <NUM>, the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> for each guidewire lumen are preferably located on every other closed cell. As shown in <FIG>, the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are located on the first closed cell <NUM> and the third closed cell <NUM>. The loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may also be located on, for example, the second closed cell <NUM> and the fourth closed cell <NUM>. If additional loops are present, then the loops may be located on closed cells separated by one closed cell. This alternating structure may prevent twisting during expansion and compression of the expansible support structure <NUM> that may damage or misalign the guidewire lumens <NUM>, <NUM>, <NUM>. Preferably, no loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be located on the fifth or proximal closed cell <NUM>. The fifth closed cell <NUM> may be adhered to the main tri-lumen shaft <NUM>. Thus, the fifth closed cell <NUM> may not fully expand during expansion of the expansible support structure <NUM> and may not be appropriate for holding loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Similarly, the fourth closed cell <NUM> may not fully expand and may also not be suitable for holding loops.

The expansible support structure <NUM>, the guidewire lumens <NUM>, <NUM>, <NUM>, and the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may initially be in a compressed state within a sheath <NUM> as described in previous examples. The sheath <NUM> may hold the expansible support structure <NUM> in a compressed state. The sheath 265may include a radiopaque marker at a distal end of the sheath <NUM> or another known location along the sheath <NUM>. The radiopaque marker may provide an indication of how much of the expansible support structure <NUM> is covered by the sheath <NUM>. This may allow for partial withdrawal of the sheath <NUM>.

The expansible support structure <NUM> may be made of Nitinol or another shape-memory material. The loop connectors <NUM> may also be made of Nitinol or another shape-memory material. The loop connectors <NUM> may be set to project inwardly from the cylindrical plane of the expansible support structure <NUM> at a given angle. The angle may be any angle, but is preferably approximately <NUM> degrees inward from the cylindrical plane. The angle or the length of the loop connectors <NUM> or both may be varied to create various positions of the guidewire lumens <NUM>, <NUM>, <NUM> within the expansible support structure <NUM>. The loops <NUM>, <NUM> corresponding to a guidewire lumen <NUM> may project in opposite directions, for example, loop <NUM> may project in a distal direction and loop <NUM> may project in a proximal direction.

When the sheath <NUM> is withdrawn from around the expansible support structure <NUM>, the expansible support structure <NUM> may expand to an expanded state. The sheath <NUM> may be partially or completely withdrawn from the expansible support structure <NUM>. During expansion of the expansible support structure <NUM>, the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may project inward from the cylindrical plane of the expansible support structure <NUM> to hold the guidewire lumens <NUM>, <NUM>, <NUM> in a predetermined position within the expansible support structure <NUM>. The guidewire lumens <NUM>, <NUM>, <NUM> may remain within the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> during expansion and compression of the expansible support structure <NUM>. Also during expansion, the angle of the connectors <NUM> relative to the closed cells may change. Placing the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> on closed cells separated by one closed cell may keep the guidewire lumens <NUM>, <NUM>, <NUM> from twisting. As the expansible support structure <NUM> expands, the guidewire lumens <NUM>, <NUM>, <NUM> may diverge into predetermined positions. The expanded catheter apparatus <NUM> may not block the vasculature.

Upon completion of a procedure, the expansible support structure <NUM> may be compressed and withdrawn from the vasculature. The sheath <NUM> may be slid distally over the expansible support structure <NUM>. Preferably, no parts of the catheter apparatus <NUM> extend outside of the cylindrical plane of the compressed expansible support structure <NUM> in the compressed state to facilitate withdrawal of the catheter apparatus <NUM>.

<FIG> shows another loop example of an expansible structure <NUM>. In contrast to the loop example <NUM> of <FIG>, the loop example of the expansible structure <NUM> of <FIG> may have loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> attached on any of closed cell <NUM>, <NUM>, <NUM>, <NUM>. The operation of the apparatus of the loop example of the expansible structure <NUM> is similar to the operation of the loop example <NUM> of <FIG>.

To prevent twisting and damage to guidewire lumens <NUM>, <NUM>, <NUM>, connecting members <NUM> may couple connection points <NUM> of struts <NUM> on a closed cell, such as <NUM>, to connection points <NUM> of struts <NUM> on an adjacent closed cell, such as <NUM>. The connection points <NUM>, <NUM> are preferably both distal or both proximal relative to the distal end of the catheter apparatus <NUM>. The number and configuration of the connecting members <NUM> may be variable. The connecting members <NUM> may have an upward bend <NUM> and a downward bend <NUM>. The bends <NUM>, <NUM> prevent twisting and damage to the guidewire lumens <NUM>, <NUM>, <NUM> during expansion and contraction of the expansible structure <NUM>. During expansion and contraction of the expansible structure <NUM>, the upward bend <NUM> and the downward bend <NUM> cancel and lateral movement of the loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The connecting members <NUM> of the expansible structure <NUM> may allow loops on each closed cell <NUM>, <NUM>, <NUM>, <NUM>. Loops <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> do not need to be on every other closed cell <NUM>, <NUM>, <NUM>, <NUM>. The example of <FIG> may provide for flexibility of the expansible structure <NUM> and may facilitate expansion and contraction during deployment and removal.

Claim 1:
A catheter apparatus (<NUM>) for advancing a guidewire through a chronic total occlusion in a vasculature comprising:
a shaft (<NUM>) having a distal portion (<NUM>);
an expansible scaffold structure (<NUM>, <NUM>) coupled to the distal portion (<NUM>) of the shaft (<NUM>); and
a single, centrally located deflectable lumen (<NUM>) passing centrally through the shaft (<NUM>) and through the expansible scaffold structure (<NUM>, <NUM>) and configured to pass over a guidewire (<NUM>), wherein the lumen (<NUM>) has a deflectable tip (<NUM>),
wherein the catheter apparatus (<NUM>) is removable from the vasculature, and
wherein the expansible scaffold structure (<NUM>, <NUM>) is configured to flare out upon a retraction of a retractable sheath (<NUM>) that covers the scaffold structure (<NUM>, <NUM>).