Patent Description:
Cardiovascular disease, including atherosclerosis, is a serious ailment for many people that may in some cases lead to death. One method for treating atherosclerosis and other forms of arterial lumen narrowing is percutaneous transluminal angioplasty, commonly referred to as "angioplasty" or "PTA," or "PTCA" when performed in the coronary arteries. The objective in angioplasty is to restore adequate blood flow through the affected artery, which may be accomplished by inflating a balloon of a balloon catheter within the narrowed lumen of the artery to dilate the vessel.

The anatomy of arteries varies widely from patient to patient. Often a patient's arteries are irregularly shaped, highly tortuous and very narrow. The tortuous configuration of the arteries may present difficulties to a clinician in advancement of the balloon catheter to a treatment site. In addition, in some instances, the extent to which the lumen is narrowed at the treatment site is so severe that the lumen is completely or nearly completely obstructed, which may be described as a total occlusion. Total or near-total occlusions in arteries can prevent all or nearly all of the blood flow through the affected arteries. If the occlusion has been established for a long period of time, the lesion may be referred to as a chronic total occlusion or CTO. Chronic total occlusions can occur in coronary as well as peripheral arteries. Chronic total occlusions are often characterized by extensive plaque formation and typically include a fibrous cap surrounding softer plaque material. This fibrous cap may present a surface that is difficult to penetrate with a conventional medical guidewire.

A number of devices have been developed and/or used for the percutaneous interventional treatment of CTOs, such as stiffer guidewires, low-profile balloons, laser light emitting wires, atherectomy devices, drills, drug eluting stents, and re-entry catheters. The factor that is most determinative of whether the physician can successfully recannalize a CTO is the physician's ability to advance a suitable guidewire from a position within the true lumen of the artery proximal to the CTO lesion, across the CTO lesion, i.e., either through the lesion or around it, and then back into the true lumen of the artery at a location distal to the CTO lesion.

In some cases, such as where the artery is totally occluded by hard, calcified atherosclerotic plaque, the guidewire may tend to deviate to one side and penetrate through the intima of the artery, thereby creating a neo-lumen called a "subintimal tract" i.e., a penetration tract formed within the wall of the artery between the intima and adventitia. In these cases, the distal end of the guidewire may be advanced to a position distal to the lesion but remains trapped within the subintimal tract. In such instances, it is then necessary to divert or steer the guidewire from the subintimal tract back into the true lumen of the artery at a location distal to the CTO lesion. The process of manipulating the guidewire to reenter the artery lumen is often difficult and solutions have been proposed utilizing various means for dealing with such a problem.

A number of catheter-based devices have been heretofore useable to redirect subintimally trapped guidewires back into the true lumen of the artery. <CIT> describes a subintimal re-entry catheter. <CIT> describes systems, apparatus and methods for treating blood vessels. <CIT> describes methods and apparatus for crossing vascular occlusions. Included among these are a variety of catheters having laterally deployable cannulae, i.e., hollow needles. For example, some catheter systems utilize a penetrator or needle that, thanks to the presence of an on-board imaging system (IVUS), exits through a side exit port of the catheter to puncture the intimal layer distal of the CTO to re-enter the true lumen of the vessel. A second guidewire is then passed through the laterally deployed needle and is advanced into the true lumen of the artery. However, a need in the art still exists for other medical catheters or systems that consistently and reliably direct subintimally advanced guidewires back into the true lumen of the artery for the treatment of a CTO.

Further aspects of the invention are defined in dependent claims <NUM>-<NUM>. Embodiments hereof are directed to an apparatus for bypassing an occlusion in a blood vessel. In an embodiment, the apparatus includes an outer shaft component, a needle component, and an inflatable balloon. The outer shaft component has a side port proximal to a distal end thereof. In addition, the outer shaft component includes a needle lumen there-through that includes a curved distal portion that bends from a longitudinal axis of the apparatus and terminates at the side port of the outer shaft component and an inflation lumen there-through configured to receive inflation fluid. The needle component is configured to be slidably disposed within the needle lumen of the outer shaft component and removable therefrom. The inflatable balloon is disposed at the distal end of the outer shaft component and is in fluid communication with the inflation lumen of the outer shaft component. The balloon includes a body portion that is disposed distal to the side port of the outer shaft component, and the body portion of the balloon has a flattened profile in an inflated state with first and second chambers that laterally extend from opposing sides of the outer shaft component for stabilizing the apparatus within a subintimal space.

In another example (not claimed) hereof, the apparatus includes an outer shaft component, a needle component, and an inflatable balloon. The outer shaft component has a side port proximal to a distal end thereof, a needle lumen there-through that includes a curved distal portion that bends from a longitudinal axis of the apparatus and terminates at the side port of the outer shaft component and an inflation lumen there-through configured to receive inflation fluid. The needle component is configured to be slidably disposed within the needle lumen of the outer shaft component and removable therefrom. The inflatable balloon is disposed at the distal end of the outer shaft component and is in fluid communication with the inflation lumen of the outer shaft component. The balloon includes an elongated proximal neck, a body portion, and a distal neck. The elongated proximal neck of the balloon is disposed proximal and distal to the side port of the outer shaft component and the body portion of the balloon is disposed distal to the distal end of the outer shaft component, the body portion of the balloon having a flattened profile in an inflated state with first and second chambers that laterally extend from opposing sides of the outer shaft component for stabilizing the apparatus within a subintimal space. At least one weld extends over the body portion of the balloon to form the first and second chambers thereof.

In another example (not claimed) hereof, the apparatus includes an outer shaft component, a needle housing, a needle component, an inflatable balloon, and a reinforced tubular component. The outer shaft component has a distal port at a distal end thereof and a side port proximal to the distal end thereof. The outer shaft component includes a needle lumen there-through that includes a curved distal portion that bends from a longitudinal axis of the apparatus and terminates at the side port of the outer shaft component, an inflation lumen there-through configured to receive inflation fluid, and a guidewire lumen that extends along at least a portion of the outer shaft component and terminates at the distal port of the outer shaft component. The guidewire lumen of the outer shaft component is configured to slidingly receive a guidewire there-through. The needle housing is disposed within the needle lumen of the outer shaft component, and includes a curved distal portion that defines the curved distal portion of the needle lumen and a transition proximal portion that has a variable flexibility along its length that decreases in a distal direction. The needle component is configured to be slidably disposed within the needle lumen of the outer shaft component and removable therefrom. The inflatable balloon is disposed at the distal end of the outer shaft component and is in fluid communication with the inflation lumen of the outer shaft component. The balloon includes a body portion that is disposed distal to the distal end of the outer shaft component, the body portion of the balloon having a flattened profile in an inflated state with first and second chambers that laterally extend from opposing sides of the outer shaft component for stabilizing the apparatus within a subintimal space. A reinforced tubular component is disposed adjacent to the distal end of the outer shaft component. The reinforced tubular component distally extends beyond the distal end of the outer shaft component through the balloon, and the reinforced tubular component defines a lumen in fluid communication with the guidewire lumen of the outer shaft component.

The method steps, in <FIG>, of use crossing an occlusion within a vessel are for illustrative purposes and do not form part of the claimed invention.

Specific embodiments of the present invention are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms "distal" and "proximal" are used in the following description with respect to a position or direction relative to the treating clinician. "Distal" or "distally" are a position distant from or in a direction away from the clinician. "Proximal" and "proximally" are a position near or in a direction toward the clinician.

Although the description of the invention is in the context of treatment of blood vessels such as smaller diameter peripheral or coronary arteries, the invention may also be used in any other body passageways where it is deemed useful. Although the description of the invention generally refers to an apparatus of bypassing a vessel blockage in a proximal-to-distal direction, i.e. antegrade or with the blood flow, the invention may be used equally well to bypass a vessel blockage in a distal-to-proximal direction, i.e. retrograde or against the blood flow, if access is available from that direction. In other terms, the apparatus and method described herein may be considered to bypass a vessel blockage from a near side of the blockage to a far side of the blockage.

Embodiments hereof relate to an apparatus for re-entering the true lumen of a vessel after subintimally bypassing an occlusion in a blood vessel such as a chronic total occlusion (CTO) of an artery. The apparatus includes an outer shaft component having a side port proximal to a distal end thereof, a needle component, and an inflatable balloon. In addition, the outer shaft component includes a needle lumen there-through that includes a curved distal portion that bends from a longitudinal axis of the apparatus and terminates at the side port of the outer shaft component and an inflation lumen there-through configured to receive inflation fluid. The needle component is configured to be slidably disposed within the needle lumen of the outer shaft component and removable therefrom. The inflatable balloon is in fluid communication with the inflation lumen of the outer shaft component and is disposed at a distal end of the outer shaft component, distally extending beyond the distal end of the outer shaft component and thereby forming the distal end of the occlusion bypassing apparatus. More particularly, the balloon includes a body portion that is disposed distal to the distal end of the outer shaft component and the body portion of the balloon has a flattened profile in an inflated state with laterally-extending first and second chambers for stabilizing the apparatus within a subintimal space.

More particularly, with reference to the figures, <FIG> illustrates a side view of an occlusion bypassing apparatus <NUM> in its deployed configuration, with <FIG> being cross-sectional views which are taken at different longitudinal locations along occlusion bypassing apparatus <NUM> as described in more detail herein. <FIG> is a perspective view of a distal portion of occlusion bypassing apparatus <NUM> (with the guidewires removed), and <FIG> is an exploded view of <FIG>. Occlusion bypassing apparatus <NUM> includes an outer shaft component <NUM> and a balloon <NUM> for stabilization or anchoring thereof. Outer shaft component <NUM> will first be described in more detail. Outer shaft component <NUM> includes a proximal end <NUM> and a distal end <NUM>. Outer shaft component <NUM> is a tubular or cylindrical element that defines a plurality of lumens formed by multi-lumen profile extrusion. More particularly, outer shaft component <NUM> includes a needle lumen <NUM> for housing a needle component <NUM>, a guidewire lumen <NUM> for housing a tracking guidewire <NUM>, and an inflation lumen <NUM> for receiving an inflation fluid.

Proximal end <NUM> of outer shaft component <NUM> extends out of the patient and is coupled to a hub <NUM> of a handle <NUM>. Inflation lumen <NUM> of outer shaft component <NUM> is in fluid communication with balloon <NUM> to allow inflation fluid received through hub <NUM> to be concurrently delivered to both lateral chambers 122A, 122B (see <FIG>) of balloon <NUM>, which will be described in more detail herein. As would be understood by one of ordinary skill in the art of balloon catheter design, hub <NUM> includes a hemostatic valve <NUM> to accommodate insertion of occlusion bypassing apparatus <NUM> and a luer <NUM> or other type of fitting that may be connected to a source of inflation fluid (not shown) and may be of another construction or configuration without departing from the scope of the present invention.

As will be explained in more detail herein, outer shaft component <NUM> has a side port <NUM> (see <FIG>) proximal to distal end <NUM> thereof. Needle lumen <NUM> includes a curved distal portion that bends from a longitudinal axis of occlusion bypassing apparatus <NUM> and terminates at side port <NUM> of outer shaft component <NUM>. A needle component <NUM> is slidably and removably disposed within needle lumen <NUM>. As used herein, "slidably" denotes back and forth movement in a longitudinal direction. While occlusion bypass apparatus <NUM> is stabilized or anchored within a subintimal space of a vessel via balloon <NUM>, a curved distal end <NUM> of needle component <NUM> is advanced out of side port <NUM> of outer shaft component <NUM> towards the true lumen of the vessel. In <FIG> and <FIG>, curved distal end <NUM> of needle component <NUM> is shown extended from side port <NUM> of outer shaft component <NUM> in a deployed configuration that is suitable for puncturing the vessel wall to gain access to the true lumen. Further, as will be described in more detail herein, needle component <NUM> is a tubular or cylindrical component that defines a lumen <NUM> there-through for slidably receiving a reentry guidewire <NUM>. As shown on <FIG>, when reentry guidewire <NUM> is introduced into occlusion bypassing apparatus <NUM>, reentry guidewire <NUM> extends proximally from handle <NUM> and extends distally from a distal tip <NUM> of needle component <NUM>.

Guidewire lumen <NUM> of outer shaft component <NUM> extends the entire length thereof for accommodating tracking guidewire <NUM> in a so-called over-the-wire configuration. As will be described in more detail herein, occlusion bypassing apparatus <NUM> includes a guidewire reinforcement component <NUM> (see <FIG>). Guidewire reinforcement component <NUM> defines a lumen <NUM> that is in fluid communication with guidewire lumen <NUM> of outer shaft component. Guidewire reinforcement component <NUM> distally extends from or beyond distal end <NUM> of outer shaft component <NUM>. In an embodiment hereof, a proximal end of guidewire reinforcement component <NUM> may be disposed adjacent to distal end <NUM> of outer shaft component <NUM> and may or may be in direct contact with distal end <NUM> of outer shaft component <NUM>. As will be described in more detail herein, a build-up tube <NUM> is disposed over or surrounds guidewire reinforcement component <NUM>. A flexible distal tip <NUM> is bonded or otherwise coupled to a distal end of build-up tube <NUM>. Flexible distal tip <NUM> forms a distal guidewire port <NUM>, as best shown on <FIG>. Thus, the guidewire lumen for occlusion bypassing apparatus <NUM> is collectively formed via guidewire lumen <NUM> of outer shaft component <NUM>, lumen <NUM> of guidewire reinforcement component <NUM>, and distal tip <NUM> that forms distal guidewire port <NUM>. The guidewire lumen for occlusion bypassing apparatus <NUM> is sized to slidingly receive tracking guidewire <NUM> so that occlusion bypassing apparatus <NUM> may be tracked thereover. As shown on <FIG>, when occlusion bypassing apparatus <NUM> is tracked over tracking guidewire <NUM>, tracking guidewire <NUM> extends proximally from handle <NUM> and extends distally from distal tip <NUM>. Tracking guidewire <NUM> is omitted from <FIG> and <FIG> in order to clearly show distal guidewire port <NUM>. In an embodiment, outer shaft component <NUM> may be sized to be used with a 5F introducer sheath with lumen <NUM> of guidewire reinforcement component <NUM> being sized to accommodate a guidewire having an outer diameter of <NUM>. As shown on the cross-sectional <FIG>, in an embodiment hereof, outer shaft component <NUM> is formed as a composite having a reinforcement layer incorporated within a polymeric body in order to enhance strength and/or flexibility and/or torquability. More particularly, outer shaft component <NUM> may include a braided or reinforcement layer <NUM> disposed thereover and a polymeric outer or external jacket <NUM> disposed over reinforcement layer <NUM>. More particularly, outer shaft component <NUM> may be formed of one or more polymeric materials, non-exhaustive examples of which include polyethylene, polyethylene block amide copolymer (PEBA), polyurethane (PU), polyamide and/or combinations thereof, either laminated, blended or co-extruded. Outer shaft component <NUM> may have a polymer hardness varying in the range of <NUM> to more than <NUM> Shore A units, including the variation of the nature of polymer. Suitable reinforcement layers for reinforcement layer <NUM> include braiding, wire mesh layers, embedded axial wires, embedded helical or coiled wires, hypotubes, and the like. In an embodiment, reinforcement layer <NUM> surrounds outer shaft component <NUM> and is a stainless steel braid reinforcement having a PPI (picks per inch of length) ranging between <NUM> to <NUM>. In an embodiment, the stiffness or flexibility of reinforcement layer <NUM> varies along its length such that a continuous variation of PPI results in a gradual variation of stiffness of outer shaft component <NUM>. Reinforcement layer <NUM> may include a stainless steel flat or ribbon wire having the thickness varying in the range <NUM> to <NUM> and a width in the range of <NUM> to <NUM>. In another embodiment, reinforcement layer <NUM> may include a round wire with diameter varying in the range of <NUM> to <NUM>. Further, the number of wires used for reinforcement layer <NUM> may vary and in one embodiment may range between <NUM> and <NUM>. Outer or external jacket <NUM>, which is disposed over or surrounds reinforcement layer <NUM>, holds down reinforcement layer <NUM> and provides a smooth outermost. Outer jacket <NUM> may be formed of one or more polymeric materials, non-exhaustive examples of which include polyethylene, polyethylene block amide copolymer (PEBA), polyurethane (PU), polyamide and/or combinations thereof, either laminated, blended or co-extruded. Although described herein as extending the full length of outer shaft component <NUM>, outer jacket <NUM> and reinforcement layer <NUM> may extend only over a portion of outer shaft component. In one embodiment, for example, at least a proximal portion of outer shaft component <NUM> may include outer jacket <NUM> and reinforcement layer <NUM>.

Other types of construction are suitable for outer shaft component <NUM>. In another embodiment (not shown), rather than a single inflation lumen that concurrently delivers inflation fluid to both first and second lateral chambers 122A, 122B of balloon <NUM> as described herein, the outer shaft component may include two inflation lumens that separately deliver inflation fluid to the first and second lateral chambers. Further, although embodiments of outer shaft component <NUM> are described above with a relatively long guidewire lumen in an over-the-wire configuration, embodiments hereof may be modified to have a rapid-exchange configuration in which the guidewire lumen extends only along a distal portion of the outer shaft component. For example, in order to provide a rapid-exchange configuration, the relatively long guidewire lumen of the above embodiment may be modified to extend only along a distal portion of the outer shaft component and may have a length between <NUM> and <NUM>.

Balloon <NUM> will now be described in more detail. As best shown on the cross-sectional view of <FIG> taken along line C-C of <FIG> and the perspective view of <FIG>, balloon <NUM> is formed such that upon inflation balloon <NUM> includes two lateral chambers 122A, 122B are disposed in parallel on opposing sides of occlusion bypassing apparatus <NUM>. Lateral chambers 122A, 122B have a flattened or laterally-extending profile when in an inflated state to anchor occlusion bypassing apparatus <NUM> within the anatomy, more particularly within the subintimal space of the vessel wall when utilized in the treatment of a CTO, so as to provide stability to occlusion bypassing apparatus <NUM>. Side port <NUM> of outer shaft component <NUM>, through which needle component <NUM> is advanced, is proximal to lateral chambers 122A, 122B of balloon <NUM>. Accordingly, lateral chambers 122A, 122B of balloon <NUM> are distal to the reentry point of needle component <NUM> in vivo. When inflated, balloon <NUM> acts as stabilization for needle component <NUM> and when deflated, balloon <NUM> is sufficiently flexible to permit maneuvering of the distal end of occlusion bypassing apparatus <NUM>. When inflated, balloon <NUM> varies the overall stiffness of the distal end of occlusion bypassing apparatus <NUM>, contributing to stabilize the apparatus during the deployment of needle component <NUM> in its most active stage. Balloon <NUM> further contributes to prevent axial dislodgement of occlusion bypassing apparatus <NUM>, as well as to orient of occlusion bypassing apparatus <NUM> towards the vessel true lumen during inflation thereof.

More particularly, as previously described, guidewire reinforcement component <NUM> distally extends beyond distal end <NUM> of outer shaft component <NUM>. With reference to <FIG> and <FIG>, guidewire reinforcement component <NUM> is a tubular or cylindrical composite element that defines lumen <NUM> there-through and includes a reinforcement layer <NUM> and a polymeric body or jacket <NUM> disposed over reinforcement layer <NUM>. Suitable reinforcement layers for layer <NUM> include braiding via a ribbon or round wire, wire mesh layers, embedded axial wires, embedded helical or coiled wires, hypotubes, and the like. Outer jacket <NUM> may be formed of one or more polymeric materials, non-exhaustive examples of which include polyethylene, polyethylene block amide copolymer (PEBA), polyurethane (PU), polyamide and/or combinations thereof, either laminated, blended or co-extruded. In an embodiment, reinforcement layer <NUM> is helical or coiled to prevent kinking and outer jacket <NUM> is a PI/PTFE composite tube to provide lubricity.

As best shown on the exploded view of <FIG> and stated above, occlusion bypassing apparatus <NUM> also includes build-up tube <NUM> disposed over or surrounding guidewire reinforcement component <NUM>. Build-up tube <NUM> is a tubular or cylindrical element that may be formed of one or more polymeric materials, non-exhaustive examples of which include polyethylene, polyethylene block amide copolymer (PEBA), polyurethane (PU), polyamide and/or combinations thereof, either laminated, blended or co-extruded. Build-up tube <NUM> functions to embed or cover guidewire reinforcement component <NUM>, and also provides a substrate for bonding or otherwise attaching balloon <NUM>. Build-up tube <NUM> ends in within distal tip <NUM>, which is bonded thereto.

As best shown on <FIG>, balloon <NUM> includes a body portion <NUM>, an elongated proximal neck <NUM>, a distal neck <NUM>, a proximal cone <NUM>, and a distal cone <NUM>. In an embodiment hereof, body portion <NUM> has a length that ranges between <NUM> and <NUM>, distal neck <NUM> has a length that ranges between <NUM> and <NUM>, and elongated proximal neck length has a length that ranges between <NUM> to <NUM>. When balloon <NUM> is inflated, body portion <NUM> of balloon <NUM> forms or includes lateral chambers 122A, 122B of balloon <NUM> as will be described in more detail herein with respect to <FIG>. Proximal cone <NUM> extends between elongated proximal neck <NUM> and body portion <NUM> of balloon <NUM>, while distal cone <NUM> extends between distal neck <NUM> and body portion <NUM> of balloon <NUM> such that body portion <NUM> of balloon <NUM> extends between or is sandwiched elongated proximal neck <NUM> and a distal neck <NUM>. When balloon <NUM> is inflated, each of proximal and distal cones <NUM>, <NUM>, respectively, extends between a <NUM> and <NUM> degree angle relative to the longitudinal axis of occlusion bypassing apparatus <NUM>. In an embodiment, distal cone <NUM> extends at a <NUM> degree angle relative to the longitudinal axis of occlusion bypassing apparatus <NUM> and proximal cone <NUM> extends at a <NUM> degree angle relative to the longitudinal axis of occlusion bypassing apparatus <NUM>. The relative angles of the proximal and distal cones may be differentiated to accomplish distally, a smoother transition to distal tip <NUM> using a <NUM> degrees distal cone <NUM>, and proximally to minimize the distance in between outer shaft component <NUM> and body portion <NUM> of balloon <NUM> with <NUM> or more degrees.

When assembled into occlusion bypassing apparatus <NUM>, elongated proximal neck <NUM> of balloon <NUM> is disposed over and bonded to outer shaft component <NUM> such that elongated proximal neck <NUM> is disposed or spans over both proximal and distal to side port <NUM> of the outer shaft component. Body portion <NUM> (and lateral chambers 122A, 122B thereof) are disposed distal to distal end <NUM> of outer shaft component and may be considered as forming the distal end of occlusion bypassing apparatus <NUM>. Distal neck <NUM> of balloon <NUM> is disposed over and bonded to build-up tube <NUM>. As best shown on <FIG>, build-up tube <NUM> and guidewire reinforcement component <NUM> disposed there-through extend through body portion <NUM> of balloon <NUM>, with lateral chambers 122A, 122B disposed in parallel on opposing sides of build-up tube <NUM> upon inflation of balloon <NUM>. Body portion <NUM> of balloon <NUM> thus has a flattened profile in an inflated state due to lateral chambers 122A, 122B that laterally extend from opposing sides of build-up tube <NUM> for stabilizing occlusion bypassing apparatus <NUM> within a subintimal space.

Formation of balloon <NUM> will now be discussed with reference to <FIG> is a schematic top view of the distal portion of the occlusion bypassing apparatus <NUM> with the guidewires removed. <FIG> is a schematic top view of the distal portion of the occlusion bypassing apparatus <NUM> with a mandrel <NUM> inserted therethrough to illustrate a manufacturing step of balloon <NUM>. In order to form lateral chambers 122A, 122B, at least one weld <NUM> extends over body portion <NUM> of balloon <NUM>. In an embodiment hereof, two welds <NUM> extend over opposing sides of body portion <NUM> of balloon <NUM> to form lateral chambers 122A, 122B thereof. Balloon <NUM> originates from a regular or known cylindrical balloon used for balloon angioplasty, i.e., a POBA or plain old balloon angioplasty balloon. When assembled over build-up tube <NUM>, a single cylindrical POBA balloon is positioned over build-up tube <NUM> such that the balloon circumferentially surrounds build-up tube <NUM>. The single cylindrical POBA balloon is laser welded to modify its shape to thereby form balloon <NUM>. More particularly, as shown in <FIG>, a fillet weld <NUM> is disposed over body portion <NUM> of balloon <NUM> to. Although not shown on the top view of <FIG>, a second fillet weld <NUM> is disposed over the opposing side of body portion <NUM> as well. During the welding step, mandrel <NUM> may be positioned through lumen <NUM> of guidewire reinforcement component <NUM> and an inflation fluid (represented by directional arrow <NUM>) is delivered as shown in <FIG>. Fillet welds <NUM> create a flat or flattened balloon profile with the top and bottom opposing sides of balloon <NUM> being attached or constrained to build-up tube <NUM> while the left and right opposing sides of balloon <NUM> are not attached or constrained to build-up tube <NUM>. In an embodiment, fillet welds <NUM> extend over the entire length of body portion <NUM> but do not extend over proximal and distal cones <NUM>, <NUM>, respectively. When inflated, the top and bottom sides of balloon <NUM> that are attached or constrained to build-up tube <NUM> remain fixed while the left and right sides of balloon <NUM> that are not attached or constrained to build-up tube <NUM> expand or inflate in opposing lateral directions away from build-up tube <NUM> to thereby form lateral chambers 122A, 122B. Lateral chambers 122A, 122B are in fluid communication with each other. When deflated, balloon <NUM> has a circular profile that conforms to build-up tube <NUM> for maneuvering occlusion bypassing apparatus <NUM> through a vasculature.

Occlusion bypassing apparatus <NUM> may include radiopaque markers in order to visually monitor the location of the apparatus in situ as well as the orientation of the apparatus. Each marker has an individual function or advantage, and collectively, the relative positioning of the multiple markers may be utilized to detect device orientation. As shown in the exploded view of <FIG> as well as the side and top views of <FIG>, respectively, cylindrical or ring first and second radiopaque markers 119A, 119B provide visibility of balloon <NUM> and thus assist in properly positioned the occlusion bypassing apparatus (balloon and outer shaft component are shown in phantom in <FIG> so that the components internal thereto are clearly shown). Markers 119A, 119B may be coupled to an annular lumen of the occlusion bypassing apparatus, such as the guidewire lumen. For example, in an embodiment, markers 119A, <NUM> are positioned over guidewire reinforcement component <NUM> to mark or indicate body portion <NUM> of balloon <NUM>. Markers 119A, 119B are positioned adjacent to proximal and distal cones <NUM>, <NUM>, respectively, of balloon <NUM>. Markers 119A, 119B indicate or mark the proximal and distal ends of body portion <NUM> of the balloon in order to provide the user with information about balloon position. Marker 119B is also positioned adjacent to distal tip <NUM> of occlusion bypassing apparatus <NUM>, and thus further provides visibility of the distal end of the apparatus during delivery and advancement thereof. Further, marker 119A functions to mark the maximum axial extension of the needle component when deployed. More particularly, marker 119A provides the user with information about the vessel portion that is potentially subject to contact the needle component when deployed.

Radiopaque marker <NUM>, which may be considered a third radiopaque marker, allows a user to properly position occlusion bypassing apparatus <NUM> across an occlusion or lesion in situ and unequivocally identify the position of side port <NUM>. <FIG> illustrates a perspective view of marker <NUM>. Marker <NUM> is an asymmetrical, S-shaped radiopaque marker that may be coupled to a distal portion of a needle housing <NUM>, which will be described in more detail herein. Marker <NUM> includes an annular or ring portion <NUM>, a first leg portion <NUM>, and a second leg portion <NUM>. Leg portions <NUM>, <NUM> extend from opposing sides of ring portion <NUM> and are <NUM> degrees offset from each other. As shown in the side and top views of <FIG>, respectively, marker <NUM> has a unique and distinctive shape depending upon the orientation of the occlusion bypassing apparatus. Due to the unique and asymmetrical shape of marker <NUM>, marker <NUM> allows a user to properly position the occlusion bypassing apparatus across an occlusion or lesion in situ and unequivocally identify the position and orientation of the side port. Collectively, the relative positioning of radiopaque markers 119A, 119B, <NUM> allow a user to identify or track the apparatus rotation across the lesion and proper needle orientation during deployment thereof. Further, markers 119A, 119B, <NUM> may be formed with different shapes, different dimensions, and/or different materials having different levels of radiopacity so that they may be distinguished from each other when in situ. Radiopaque markers 119A, 119B, <NUM> may be formed from Platinum-Iridium alloys, gold, tantalum, and/or loaded polymeric materials.

It will be understood by those of ordinary skill in the art that occlusion bypassing apparatuses described herein may utilize alternative radiopaque marker configurations and patterns in order to properly position the occlusion bypassing apparatus. For example, <FIG> illustrates another configuration of a radiopaque marker <NUM> that may be used in embodiments herein. Marker <NUM> may be coupled to a distal portion of needle housing <NUM>. Marker <NUM> is generally T-shaped and includes an annular or ring portion <NUM>, a first leg portion <NUM>, and a second leg portion <NUM>. Leg portions <NUM>, <NUM> extend from opposing sides of ring portion <NUM> but are not circumferentially offset from each other. Due to its asymmetry, marker <NUM> has a unique and distinctive shape depending upon the orientation of the occlusion bypassing apparatus. Due to the unique shape of marker <NUM>, marker <NUM> allows a user to properly position the occlusion bypassing apparatus across an occlusion or lesion in situ and unequivocally identify the position and orientation of the side port. Additional marker configurations may also be used in embodiments described herein, including but not limited to an L-shaped radiopaque marker <NUM> shown in <FIG>. Marker <NUM> may be coupled to a distal portion of needle housing <NUM>. Marker <NUM> includes an annular or ring portion <NUM> and a leg portion <NUM> extending from one end thereof. Due to its asymmetry, marker <NUM> has a unique and distinctive shape depending upon the orientation of the occlusion bypassing apparatus. Due to the unique shape of marker <NUM>, marker <NUM> allows a user to properly position the occlusion bypassing apparatus across an occlusion or lesion in situ and unequivocally identify the position and orientation of the side port.

Needle lumen <NUM> of outer shaft component <NUM> houses needle housing <NUM>. More particularly, needle housing <NUM> lays within needle lumen <NUM> of outer shaft component <NUM>, or stated another way is disposed within a distal portion of needle lumen <NUM> of outer shaft component <NUM>. Accordingly, with reference back to <FIG>, <FIG> is a cross-sectional view taken along line A-A of <FIG> that shows needle component <NUM> within needle lumen <NUM>, while <FIG> is a cross-sectional view taken along line B-B of <FIG> (which is taken at a more distal longitudinal location along occlusion bypassing apparatus <NUM>) that shows needle component <NUM> within needle housing <NUM>. Needle housing <NUM> is a tubular or cylindrical shaft component that is disposed at the distal portion of needle lumen <NUM>, with a proximal end thereof (i.e., the two proximal-most tabs thereof) being embedded into the polymeric material of outer shaft component <NUM>. Needle housing <NUM> defines a lumen sized and configured to slidably and removably receive needle component <NUM> there-through. When needle component <NUM> is positioned within occlusion bypassing apparatus <NUM>, needle component <NUM> is disposed or extends through needle lumen <NUM> of outer shaft component <NUM> and through lumen <NUM> (see <FIG>) of needle housing <NUM>.

In an embodiment hereof, needle housing <NUM> is a metallic tube of a relatively short length. Typically, the needle housing length is about <NUM>-<NUM>% of the needle lumen length. Needle housing <NUM> is preferably formed from a shape memory material such as nitinol to ensure high flexibility of occlusion bypassing apparatus <NUM> during advancement through the vasculature. Alternatively, needle housing <NUM> may be formed from a metallic resilient material such as steel or spring temper stainless steel.

With reference to <FIG>, needle housing <NUM> includes a proximal transition portion <NUM> with a variable flexibility and a curved distal portion <NUM> that bends from the longitudinal axis LA of occlusion bypassing apparatus <NUM>. <FIG> is a side view of needle housing <NUM>, wherein the needle housing is removed from occlusion bypassing apparatus <NUM> for illustrative purposes only. <FIG> is a top view of needle housing <NUM>. Curved distal portion <NUM> includes a pre-formed or pre-shaped bend or curve. A heat or thermal treatment of the selected material of needle housing <NUM> may be used to set the shape of curved distal portion <NUM>. More particularly, as shown in <FIG>, curved distal portion <NUM> extends, bends, or otherwise curves in a circular path while the remaining length of needle housing <NUM> is straight and extends parallel to the longitudinal axis LA of occlusion bypassing apparatus <NUM>. In an embodiment hereof, curved distal portion <NUM> extends in a circular path and forms a portion of a circle having a radius R. In an embodiment hereof, radius R is <NUM>. Typically, radius R is in the range from <NUM> to <NUM>. As best shown in the sectional views of <FIG>, distal portion <NUM> of needle housing <NUM> terminates at side port <NUM> of outer shaft component <NUM> The curved distal portion <NUM> of needle housing <NUM> functions as a guide to direct needle component <NUM> through side port <NUM> such that needle component <NUM> exits occlusion bypassing apparatus <NUM> in a stable configuration at a desired orientation for re-entry into a true lumen. As shown in <FIG>, in an embodiment, a distal end of curved distal portion <NUM> is angulated with respect to the longitudinal axis LA of occlusion bypassing apparatus <NUM>. In <FIG>, the distal end of curved portion <NUM> is angled at an angle of <NUM>° with respect to the longitudinal axis LA of occlusion bypassing apparatus <NUM>. In another embodiment hereof (not shown), a distal end of curved distal portion <NUM> is straight or parallel to the longitudinal axis LA of occlusion bypassing apparatus <NUM>.

In order to smooth or bridge the transition between flexible needle lumen <NUM> and relatively stiffer or less flexible needle housing <NUM>, needle housing <NUM> includes proximal transition portion <NUM>. Transition portion <NUM> has a variable flexibility along its length that decreases in a distal direction as indicated by directional arrow <NUM> (see <FIG>). Since the flexibility of transition portion <NUM> decreases in a distal direction, the transition portion allows for a gradual modulation of the flexibility between the flexible needle lumen <NUM> (located proximal to transition portion <NUM>) and relatively less flexible, or rigid, remaining length of needle housing <NUM> (located distal to transition portion <NUM>). The flexibility of occlusion bypassing apparatus <NUM> corresponds to the flexibility of needle housing <NUM>, with occlusion bypassing apparatus <NUM> being more flexible proximal to needle housing <NUM> and less flexible along needle housing <NUM>. Transition portion <NUM> similarly will provide occlusion bypassing apparatus <NUM> with a variable flexibility along its length that decreases in a distal direction.

In order to provide transition portion <NUM> of needle housing <NUM> with varying flexibility, transition portion <NUM> includes a plurality of apertures <NUM>, wherein pairs of apertures align with each other along a respective transverse axis of needle housing <NUM>. Each aperture is a cut-out portion or window that increases the flexibility of transition portion <NUM> as compared to the remaining length of needle housing <NUM>, i.e., straightening portion <NUM> of needle housing <NUM> and curved distal portion <NUM> which have no apertures or cut-out portions formed therein. As used herein, any respective pair of aligned apertures may be referred to singularly or collectively as a pair or pairs of aligned apertures <NUM>. Although shown with seven pairs of aligned apertures <NUM>, a greater or lesser number of pairs of aligned apertures <NUM> may be used to provide transition portion <NUM> with varying flexibility. As further described in <CIT> (Attorney Docket No. C00007385 USU1). each aperture in a pair of aligned apertures <NUM> has an hourglass shape and is disposed from the other aperture of the pair on an opposite side of the perimeter or outer surface of needle housing <NUM> so as to be diametrically opposed thereto. In order to provide transition portion <NUM> with varying flexibility along its length that decreases in a distal direction, the pitch or spacing between adjacent pairs of aligned apertures increases in a distal direction. The distance or spacing between adjacent pairs of aligned apertures <NUM> continues to increase such that distance or spacing between the most distal apertures is the greatest. Since a greater amount of metallic material extends between consecutive pairs of aligned apertures <NUM>, gradually increasing the pitch or spacing between axially adjacent pairs of aligned apertures <NUM> in the distal direction results in a gradual decrease of flexibility in the distal direction. In addition or in the alternative to varying the spacing between adjacent pairs of aligned apertures <NUM>, in another embodiment the size or area of adjacent pairs of aligned apertures <NUM> may be varied in order to result in a gradual decrease of flexibility along the length of transition portion <NUM> in the distal direction as further described in <CIT> (Attorney Docket No. C00007385 USU1).

<FIG> is an enlarged perspective view of a distal tip of needle housing <NUM>. More particularly, in order to improve embedding of needle housing <NUM> within outer shaft component <NUM>, a small opening or skive cut <NUM> is formed at the very distal tip of curved distal end <NUM>. Skive cut <NUM> grabs or embeds into the polymeric material of outer shaft component <NUM> and/or elongated proximal neck <NUM> of balloon <NUM> which encapsulates needle housing <NUM> within occlusion bypassing apparatus <NUM> to aid in securing needle housing <NUM> within outer shaft component <NUM>.

It will be understood by those of ordinary skill in the art that occlusion bypassing apparatuses described herein may utilize alternative needle housing configurations and patterns. More particularly, <FIG> is a side view of a needle housing <NUM> according to another embodiment hereof, wherein the needle housing is removed from an occlusion bypassing apparatus for illustrative purposes only. <FIG> is a top view of needle housing <NUM>. Needle housing <NUM> has a curved distal portion <NUM> which is similar to curved distal portion <NUM>. In order to provide needle housing <NUM> with varying flexibility, a proximal portion of needle housing <NUM> includes a tab <NUM> formed by a skive cut which has a variable flexibility along its length that decreases in a distal direction. Further, tab <NUM> is more flexible that the remaining length of needle housing <NUM> i.e., straightening portion <NUM> of needle housing <NUM> and curved distal portion <NUM> which have no cut-out portions formed therein. A width of tab <NUM> increases along its length such that a distal end thereof is wider than a proximal end thereof. At least a portion of tab <NUM> is configured to be embedded into the polymeric material of outer shaft component <NUM>. In an embodiment, the entire length of tab <NUM> is embedded into the polymeric material of outer shaft component <NUM>. Further, tab <NUM> provides proper orientation of the exit port of needle housing <NUM> during assembly of the needle housing into the outer shaft component.

<FIG> is a side view of a needle housing <NUM> according to another embodiment hereof, wherein the needle housing is removed from an occlusion bypassing apparatus for illustrative purposes only. <FIG> is a top view of needle housing <NUM>. Needle housing <NUM> has a curved distal portion <NUM> which is similar to curved distal portion <NUM>. In order to provide needle housing <NUM> with varying flexibility, a proximal portion of needle housing <NUM> includes an expandable stent <NUM> which is more flexible that the remaining length of needle housing <NUM> i.e., straightening portion <NUM> of needle housing <NUM> and curved distal portion <NUM> which have no apertures or cut-out portions formed therein. Stent <NUM> is self-expanding and is configured to expand into apposition with the polymeric material of outer shaft component <NUM>. More particularly, stent <NUM> is a tubular frame or scaffold that defines a plurality of diamond or kite-shaped openings, with each diamond-shaped opening being defined by four vertexes or vertices and four segments or struts extending or formed between vertexes. In this embodiment, stent <NUM> has a lattice or mesh configuration which is laser cut from a tube and is formed as a unitary structure or component. In embodiments hereof, stent <NUM> may be made from stainless steel, a pseudo-elastic metal such as a nickel titanium alloy or Nitinol, or a so-called super alloy, which may have a base metal of nickel, cobalt, chromium, or other metal.

<FIG> is a side view of a needle housing <NUM> according to another embodiment hereof, wherein the needle housing is removed from an occlusion bypassing apparatus for illustrative purposes only. <FIG> is a top view of needle housing <NUM>. Needle housing <NUM> has a curved distal portion <NUM> which is similar to curved distal portion <NUM>. In order to provide needle housing <NUM> with varying flexibility, a proximal portion of needle housing <NUM> includes an expandable stent <NUM> which is more flexible that the remaining length of needle housing <NUM> i.e., straightening portion <NUM> of needle housing <NUM> and curved distal portion <NUM> which have no apertures or cut-out portions formed therein. Stent <NUM> is a tubular frame or scaffold that defines a plurality of diamond or kite-shaped openings, with each diamond-shaped opening being defined by four vertexes or vertices and four segments or struts extending or formed between vertexes. In this embodiment, stent <NUM> has a lattice or mesh configuration which is laser cut from a tube and is formed as a unitary structure or component. Stent <NUM> is self-expanding and may be made from stainless steel, a pseudo-elastic metal such as a nickel titanium alloy or Nitinol, or a so-called super alloy, which may have a base metal of nickel, cobalt, chromium, or other metal. However, rather than being configured to expand into apposition with the polymeric material of the outer shaft component as described with respect to stent <NUM>, stent <NUM> is sized and configured to embrace or surround an outer surface of the outer shaft component. More particularly, as shown in <FIG>, and <FIG>, stent <NUM> becomes the distal end of a braided or reinforcement layer <NUM> disposed over an outer shaft component <NUM> and a polymeric external jacket (such as external jacket <NUM> described herein but not shown in <FIG>, and <FIG> for purposes of clarity) is over-molded onto stent <NUM> to secure or attach stent <NUM> and needle housing <NUM> to outer shaft component <NUM>. The remaining length of needle housing <NUM>, i.e., straightening portion <NUM> of needle housing <NUM> and curved distal portion <NUM> which have no apertures or cut-out portions formed aligns with a needle lumen <NUM> of outer shaft component <NUM> so stent <NUM> is eccentric with respect to straightening portion <NUM> of needle housing <NUM> and curved distal portion <NUM>. As shown in <FIG>, and <FIG>, needle component <NUM> (which defines lumen <NUM> for receiving reentry guidewire <NUM> as described herein) is slidingly disposed through aligned needle lumen <NUM> of outer shaft component <NUM> and the remaining length of needle housing <NUM>, i.e., straightening portion <NUM> of needle housing <NUM> and curved distal portion <NUM>. In this embodiment, a distal end <NUM> of outer shaft component <NUM> terminates within stent <NUM> and thus the occlusion bypassing system includes a first connection shaft <NUM> which extends within a distal portion of a guidewire lumen <NUM> and distally extends beyond distal end <NUM> of outer shaft component <NUM> to bridge or connect the guidewire lumen of the outer shaft component to a guidewire reinforcement component (such as guidewire reinforcement component <NUM> described herein but not shown in <FIG>, and <FIG>) and a second connection shaft <NUM> which extends within a distal portion of an inflation lumen <NUM> and distally extends beyond distal end <NUM> of outer shaft component <NUM> to bridge or connect the inflation lumen of the outer shaft component to the inlet or interior of a balloon (such as balloon <NUM> described herein but not shown in <FIG>, and <FIG>). First and second connection shafts <NUM>, <NUM> may be formed of poli-imide or other suitable polymeric materials.

Needle component <NUM>, which is shown removed from occlusion bypassing apparatus <NUM> in <FIG>, is a tubular or cylindrical element that is configured to be slidably disposed within lumens <NUM>, <NUM> of outer shaft component <NUM>, needle housing <NUM>, respectively, and removable therefrom. More particularly, needle component <NUM> is disposed within outer shaft component <NUM> and needle housing <NUM> such that there is sufficient space or room therebetween for needle component <NUM> to be movable or slidable in a longitudinal direction relative to outer shaft component <NUM> and needle housing <NUM>. In order to accommodate reentry guidewire <NUM> that may be utilized during a method of subintimally crossing an occlusion as will be discussed in more detail herein, needle component <NUM> may be a hypotube that defines a lumen <NUM> there-through as shown in the cross-sectional view of <FIG>. In an embodiment, lumen <NUM> of needle component <NUM> is sized to accommodate a guidewire having an outer diameter equal to or less than <NUM> such that occlusion bypassing apparatus <NUM> has a low profile. A proximal end of needle component <NUM> is housed within handle <NUM> and distal tip <NUM> of needle component <NUM> is configured to pierce or penetrate through a wall of a vessel when extended or deployed.

Needle component <NUM> includes an elongated first or proximal segment <NUM> that extends substantially parallel with longitudinal axis LA of occlusion bypassing apparatus <NUM> and curved distal end <NUM> distally extending from a distal end of proximal segment <NUM>. Curved distal end <NUM> is pre-formed in a bent or curved shape or configuration. More particularly, as shown in <FIG>, curved distal end <NUM> extends, bends, or otherwise curves in a circular path. In an embodiment hereof, curved distal end <NUM> extends in a circular path approximately <NUM>° from a distal end of proximal segment <NUM>, thereby forming a portion of a circle having a radius R. "Approximately" as used herein includes angles with a plus or minus <NUM>° error margin. In an embodiment hereof, radius R is <NUM>. At least curved distal end <NUM> of needle component <NUM> is formed from a biocompatible resilient metal such as spring temper stainless steel or nitinol, which utilizes the elastic properties of stress induced martensite, such that a heat or thermal treatment of the selected material may be used to set the shape of curved distal end <NUM>. In an embodiment, needle component <NUM> may be formed from more than one material, for e.g., with proximal segment <NUM> being formed of stainless steel and only curved distal end <NUM> being formed of nitinol. With additional reference to <FIG>, curved distal portion <NUM> of needle housing <NUM> is formed with the same curvature as curved distal end <NUM> of needle component <NUM> so that an automatic centering design is obtained. More particularly, curved distal portion <NUM> of needle housing <NUM> includes a bend or turn that corresponds with, matches or is the same as the bend or turn of curved distal end <NUM> of needle component <NUM>. The bend of curved distal portion <NUM> of needle housing <NUM> is formed with the same radius R as the bend of curved distal end <NUM> of needle component <NUM> so that the needle component <NUM> exits side port <NUM> of outer shaft component <NUM> at or with the correct orientation for re-entry of a true lumen of a vessel. By forming curved distal portion <NUM> of needle housing <NUM> and curved distal end <NUM> of needle component <NUM> with identical curvatures or radiuses, needle component <NUM> is very stable inside needle housing <NUM>, thus minimizing any rotation or relative movement between the two components, especially during the needle deployment.

In another embodiment hereof, the needle component may include a straight segment disposed between the curved distal end and the distal tip. More particularly, <FIG> is a side view of a distal portion of a needle component <NUM> according to another embodiment hereof, wherein the needle component includes a straight segment <NUM> disposed between curved distal end <NUM> and distal tip <NUM>. Straight segment <NUM> may range between <NUM> and <NUM> in length, and functions to improve the angulation of reentry guidewire <NUM> into the vessel true lumen. Stated another way, straight segment <NUM> improves the direction of reentry guidewire <NUM> so that reentry guidewire <NUM> exits from needle component <NUM> and is directed distal of the occlusion rather than being directed backward toward the occlusion.

In addition, the needle component may include a radiopaque marker to improve visibility thereof and allow a user to visually check and then correctly track the deployment of the needle component. For example, <FIG> is a side view of a distal portion of a needle component <NUM> according to another embodiment hereof, wherein the needle component includes an encapsulated radiopaque marker <NUM> proximal to distal tip <NUM> thereof. In an embodiment, marker <NUM> is a small gold pill can be inserted within a recess formed on an outer surface of needle component <NUM>. As another example, <FIG> is a side view of a distal portion of a needle component <NUM> according to another embodiment hereof, wherein the needle component includes a curved distal portion <NUM> and a distal tip <NUM>, wherein distal tip <NUM> and a portion of distal portion <NUM> is coated in a radiopaque coating <NUM>. Radiopaque coating <NUM> is a thin layer of material and may be formed by sputtering, dipping, or other suitable process.

With reference now to <FIG>, in a first or delivery configuration of the apparatus the curved distal end <NUM> of needle component <NUM> is held or restrained in a straightened form within needle housing <NUM>. Balloon <NUM> and inflation lumen <NUM> are not shown in <FIG> since the sectional view is taken approximately through the midline of occlusion bypassing apparatus <NUM> and proximal to distal end <NUM> of outer shaft component <NUM>. Needle housing <NUM> is formed from a relatively stiff or less flexible material as described above in order to effectively straighten curved distal end <NUM> of needle component <NUM>. More particularly, in an embodiment hereof, needle component <NUM> is pre-loaded within occlusion bypassing apparatus <NUM> and curved distal end <NUM> of needle component <NUM> is held or restrained in a straightened form within straightening portion <NUM> of needle housing <NUM> which has no apertures or cut-out portions formed therein. Since needle housing <NUM> is formed with varying flexibility, straightening portion <NUM> of needle housing <NUM> with no apertures or cut-out portions is relatively stiffer or less flexible to ensure straightening of curved distal end <NUM> of needle component <NUM>. Straightening portion <NUM> of needle housing <NUM> holds the curved distal end of the needle component in a straightened form during advancement of occlusion bypassing apparatus <NUM> in the human vasculature.

In the sectional view of <FIG>, curved distal end <NUM> of needle component <NUM> extends from side port <NUM> of outer shaft component <NUM> and bends or curves from longitudinal axis LA of the apparatus. Balloon <NUM> and inflation lumen <NUM> are not shown in <FIG> since the sectional view is taken approximately through the midline of occlusion bypassing apparatus <NUM> and proximal to distal end <NUM> of outer shaft component <NUM>. More particularly, when it is desired to distally advance needle component <NUM> through side port <NUM> of outer shaft component <NUM>, it must first be confirmed that side port <NUM> is positioned beyond or distal to the target occlusion and is oriented in the direction of the true lumen of the vessel. The position and orientation of occlusion bypassing apparatus may be monitored via radiopaque markers 119A, 119B, <NUM> of apparatus <NUM> described above. Once side port <NUM> is positioned and oriented as desired, needle component <NUM> is distally advanced relative to outer shaft component <NUM> such that curved distal end <NUM> is no longer constrained by needle housing <NUM> but rather is extended to protrude from side port <NUM> of outer shaft component <NUM>. When released from needle housing <NUM>, curved distal end <NUM> resumes its pre-formed shape or geometry by its own internal restoring forces. As described with respect to <FIG>, curved distal end <NUM> extends, bends, or otherwise curves in a circular path, thereby forming a portion of a circle having a radius R. When needle component <NUM> is distally advanced or extended as best shown in <FIG>, <FIG>, and <FIG>, distal tip <NUM> may be used to penetrate through the vessel wall and re-enter a true lumen of a vessel as described herein. As described above, by forming the bend of curved distal end <NUM> of needle component <NUM> with the same curvature or radius as the bend of curved distal portion <NUM> of needle housing <NUM>, deployed needle component <NUM> is very stable inside needle housing <NUM>, thus minimizing any rotation or relative movement between the two components. Balloon <NUM> may be expanded or inflated to anchor outer shaft component <NUM> within a subintimal tract either before or after the distal advancement of needle component <NUM>. In an alternative method of the present invention, according to the physician's experience during the procedure he may realize that the subintimal space is sufficiently narrow and suitably envelops the occlusion bypassing apparatus that the latter is properly anchored within the subintimal space. Therefore, in this case there could be no need for expanding the balloon.

Occlusion bypassing apparatus <NUM> may have handle <NUM> coupled thereto in order to assist in the manipulation of needle component <NUM> and outer shaft component <NUM>. As shown in <FIG> and <FIG>, handle <NUM> includes a knob or cogwheel <NUM> and a slider <NUM>. <FIG> is a perspective view of handle <NUM> with guidewires <NUM>, <NUM> removed, while <FIG> is a sectional perspective view of handle <NUM> with guidewires <NUM>, <NUM> removed. Hub <NUM>, previously described herein, extends between knob <NUM> and outer shaft component <NUM>. Knob <NUM> is coupled to outer shaft component <NUM> such that rotation of the knob results in rotation of the outer shaft, as well as any components attached thereto or incorporated therein such as needle housing <NUM>. More particularly, if a user needs to rotate outer shaft component <NUM> in order to orient side port <NUM> towards a true lumen of a vessel, the user turns knob <NUM> to manipulate outer shaft component <NUM> as desired. Slider <NUM> is attached to needle component <NUM> such that operation of slider <NUM> results in deployment or retrieval of the needle component. More particularly, when it is desired to deploy or retrieve needle component <NUM>, slider <NUM> is pushed or pulled within a recess <NUM> formed on handle <NUM>. Handle <NUM> also includes a tubular component <NUM> (shown in <FIG>) that houses needle component <NUM> within the handle in order to prevent kinking of the needle component. Further, handle <NUM> also includes a flushing luer <NUM> (shown in <FIG>) so that occlusion bypassing apparatus <NUM> may be flushed prior to use within the vasculature in accordance with techniques known in the field of interventional cardiology and/or interventional radiology. Flushing of occlusion bypassing apparatus <NUM> is described in more detail herein.

<FIG> is an enlarged perspective view of a proximal end of handle <NUM>, while <FIG> is an enlarged perspective view of the distal portion of the occlusion bypassing apparatus <NUM>. As best shown on <FIG>, flushing luer <NUM> is configured to permit exit of both tracking guidewire <NUM> and reentry guidewire <NUM> from the proximal end of handle <NUM>. As shown on <FIG>, tracking guidewire <NUM> exits from distal tip <NUM> of occlusion bypassing apparatus <NUM> while reentry guidewire <NUM> exits from distal tip <NUM> of needle component <NUM>. In another embodiment hereof, the flushing luer may be configured to only permit exit of reentry guidewire <NUM> and tracking guidewire <NUM> may exit distal to handle <NUM>. For example, <FIG> is an enlarged perspective view of a hub <NUM> that may be utilized in embodiments hereof, wherein the hub has an exit port <NUM> formed therein. In this embodiment, tracking guidewire <NUM> used to track occlusion bypassing apparatus <NUM> through the vasculature is intended to exit before handle <NUM>. Exit port <NUM> is a dedicated recess drawn within hub <NUM> which bridges or extends between handle <NUM> and the outer shaft component (not shown in <FIG>).

The handle may incorporate various additional features. For example, <FIG> is an enlarged perspective view of a hub <NUM> that includes a bail-out feature so that the hub may be disengaged or disconnected from the handle. Such a bail-out feature may be useful where, for any reasons, the handle and/or the apparatus fails such as but not limited to when retraction of needle component <NUM> cannot be accomplished. More particularly, handle <NUM> allows detachment of hub <NUM> that bridges or extends between handle <NUM> and the outer shaft component (not shown in <FIG>). Hub <NUM> includes threads <NUM> that mate with helical recesses <NUM> formed within a knob <NUM> of handle <NUM> to allow for separation or detachment of handle <NUM> from occlusion bypassing apparatus <NUM>. When handle <NUM> is manually separated or detached from occlusion bypassing apparatus <NUM>, needle component <NUM> is concurrently retracted within outer shaft component <NUM> since the needle component <NUM> is attached to the flushing luer at the proximal end of the handle (not shown on <FIG>). In this case, when a bail-out is required, the user pulls back handle <NUM> with one hand while keeping the other hand over hub <NUM> to detach or separate handle <NUM>, and needle component <NUM> is thereby retracted within outer shaft component <NUM>. <FIG> illustrates handle <NUM> while separating from hub <NUM>. Although shown as being detachably coupled via threads, handle <NUM> may be detachably coupled to hub <NUM> via other coupling features like detachable bonds or adhesives.

<FIG> is a side sectional view of a slider <NUM> that may be utilized in embodiments hereof, wherein the slider includes a built-in safety mechanism. Moreover, handle <NUM> includes a safety blockage of slider <NUM> to prevent unintended needle deployment while tracking through the vasculature. Slider <NUM> includes a radial extension or tab <NUM> on an underside surface thereof that engages or is received into a recess <NUM> formed on a housing or shell of handle <NUM>. Tab <NUM> secures slider <NUM> in a locked position until the user exerts a force onto slider <NUM> to disengage tab <NUM> from recess <NUM> when deployment of needle component <NUM> is desired.

<FIG> illustrate another handle feature that may be utilized in embodiments hereof. More particularly, handle <NUM> is configured to permit a two-stage needle deployment if desired. Handle <NUM> includes a removable stopper <NUM> built into the housing or shell of handle <NUM>. Stopper <NUM> is shown positioned on handle <NUM> in <FIG>, thus resulting in standard needle deployment depth, and stopper <NUM> is shown removed from handle <NUM> in <FIG>, thus resulting in additional or extra needle deployment depth. Stopper <NUM> is loaded or positioned onto handle <NUM> during assembly or packaging of the apparatus. When stopper <NUM> is positioned on handle <NUM> as shown in <FIG>, occlusion bypassing apparatus <NUM> is configured for a standard needle deployment depth of approximately <NUM>-<NUM>. When stopper <NUM> is removed as shown in <FIG>, slider <NUM> and needle component <NUM> may be further distally advanced and thus occlusion bypassing apparatus <NUM> is configured for an extra <NUM> needle deployment depth such that the total needle deployment depth is <NUM>-<NUM>. The extra needle deployment depth may be desirable depending upon application. For example, occlusion bypassing apparatus <NUM> may be designed or configured for treatment within a peripheral vasculature for use in SFA and Popliteal arteries. However, since from proximal SFA to distal popliteal the trunk size of the artery narrows down of some millimeters, the extra <NUM> needle deployment depth is designed to cover this gap. Stopper <NUM> may be removed after needle component <NUM> is deployed the standard deployment depth and it is determined that additional or extra depth is desired. Stopper <NUM> thus permits either a single-step needle deployment when the standard deployment depth is sufficient (and thus stopper <NUM> is not required to be removed), or a two-step needle deployment when additional or extra depth is desired (and thus stopper <NUM> is removed following the first step of needle deployment to the standard deployment depth).

<FIG> is a sectional view of the anatomy of an artery wall, which for purposes of this description is shown to consist essentially of three layers, the tunica intima I ("intima"), tunica media M ("media") which is the thickest layer of the wall, and the tunica adventitia A ("adventitia"). In some arteries an internal elastic membrane IEM is disposed between the media M and adventitia A. The adventitia A is made of collagen, vasa vasorum and nerve cells, the media M is made of smooth muscle cells, and the intima I is made up of a single layer of endothelial cells that provide a nonthrombogenic surface for flowing blood. Occlusion bypassing apparatus <NUM> is used as part of a system for creating a subintimal reentry tract within a wall of a blood vessel V to allow blood flow around an occlusion. <FIG> illustrate an exemplary method of using the above-described occlusion bypassing apparatus <NUM> to bypass a chronic total occlusion (CTO) according to an embodiment hereof. Although described in relation to bypassing a CTO, it should be understood that the methods and apparatus described herein may be used for bypassing any tight stenoses in arteries or other anatomical conduits and are not limited to total occlusions.

Prior to use of occlusion bypassing apparatus <NUM> within the vasculature, it may be desirable to flush the apparatus in accordance with techniques known in the field of interventional cardiology and/or interventional radiology. Flushing of occlusion bypassing apparatus <NUM> may be performed through lumen <NUM> of needle component <NUM>. More particularly, small openings or holes (not shown) may be provided on needle component <NUM>. In order to perform the initial flushing of occlusion bypassing apparatus <NUM>, side port <NUM> of outer shaft component <NUM> is occluded. Saline solution is introduced into a proximal end of lumen <NUM> of needle component <NUM> and flushes lumen <NUM>. Since side port <NUM> is occluded, the saline solution exits from the small holes formed on needle component <NUM> and flushes needle lumen <NUM> of outer shaft component and lumen <NUM> of needle housing <NUM>.

As shown in <FIG>, in accordance with techniques known in the field of interventional cardiology and/or interventional radiology, tracking guidewire <NUM> having a distal end <NUM> is transluminally advanced through the vasculature to a position upstream of a treatment site, which in this instance is shown as occlusion O within a true lumen TL of blood vessel V. Tracking guidewire <NUM> pierces the intima I and is advanced distally to create a subintimal tract by locally dissecting or delaminating intima I from media M or by burrowing through media M. In order to pierce the intima I, a clinician may manipulate distal end <NUM> of tracking guidewire <NUM> by prolapsing or bending-over the distal end of tracking guidewire <NUM> (not shown) and thereafter may use the stiffer arc or loop of the prolapsed distal end to pierce into the intima I to advance tracking guidewire <NUM> there through. The piercing of the intima I is aided by the fact that typically blood vessel V is diseased, which in some instances makes the intima I prone to piercing. Tracking guidewire <NUM> is distally advanced within the subintimal tract from a near side of occlusion O to a position where distal end <NUM> thereof is positioned in the subintimal tract on a far side of occlusion O.

Alternatively, another device other than tracking guidewire <NUM> initially may be used to create the subintimal tract. Those of ordinary skill in the art will appreciate and understand the types of alternative devices that may be used in this step including an apparatus known as an "olive", a laser wire, an elongate radiofrequency electrode, a microcatheter, or any other device suitable for boring or advancing through the vessel tissue. As another example, a guidewire other than tracking guidewire <NUM> may be utilized to create the subintimal tract. More particularly, a guidewire having a relatively larger outer diameter than tracking guidewire <NUM>, such as between <NUM>-<NUM>, may be utilized to create the subintimal tract because a larger guidewire has greater column strength to gain access to the subintimal space of vessel V. If an alternative device is used instead of tracking guidewire <NUM> to form the subintimal tract, such alternative device may be removed and replaced with tracking guidewire <NUM> after the subintimal tract has been formed.

After the subintimal tract is formed and guidewire <NUM> is in place as desired, occlusion bypassing apparatus <NUM> may be tracked over guidewire <NUM> and advanced such that distal tip <NUM> is adjacent to the far or downstream end of occlusion O as shown in <FIG>. In an embodiment, needle component <NUM> is pre-loaded within occlusion bypassing apparatus <NUM>. During the step of advancing occlusion bypassing apparatus <NUM> over guidewire <NUM>, curved distal end <NUM> of needle component <NUM> is held or restrained in a straightened form within needle housing <NUM> as described above. In another embodiment, needle component <NUM> is not positioned or disposed within occlusion bypassing apparatus <NUM> when occlusion bypassing apparatus <NUM> is initially advanced over guidewire <NUM> but rather is subsequently introduced into the apparatus. Utilizing the radiopaque markers of apparatus <NUM>, occlusion bypassing apparatus <NUM> should be positioned and oriented such that side port <NUM> of outer shaft component <NUM> is positioned beyond or distal to the target occlusion and is oriented in the direction of the true lumen of the vessel.

Once outer shaft component <NUM> is positioned as desired, balloon <NUM> may be expanded or inflated as shown in <FIG>, thus anchoring outer shaft component <NUM> in the subintimal tract. <FIG> illustrates a cross-sectional view of apparatus <NUM> within a vessel V having a true lumen TL and a subintimal space SS. The subintimal space SS may be described as having an arc, curve, or C shape. When inflated, lateral chambers 122A, 122B of balloon <NUM> expand into contact with the surrounding patient's anatomy to fill out or occupy the subintimal space SS to improve anchoring and to minimize damage to the surrounding anatomy. In addition, although balloon <NUM> is described herein for providing stabilization during distal advancement or deployment of needle component <NUM>, in another embodiment hereof (not shown) inflation of balloon <NUM> may also be used to create or assist in creating the subintimal tract. In such an embodiment, balloon <NUM> may be inflated multiple times in the subintima to initially support delivery of the occlusion bypassing apparatus across the lesion within the subintima and then subsequently during a re-entry procedure.

With reference to <FIG>, needle component <NUM> is then deployed through side port <NUM> of occlusion bypassing apparatus <NUM>. Needle component <NUM> is distally advanced relative to outer shaft component <NUM> and needle housing <NUM> until curved distal end <NUM> extends from or protrudes out of side port <NUM> of outer shaft component <NUM> such that distal tip <NUM> of the needle component penetrates the intima to gain access to the true lumen of the vessel distal to, i.e., downstream of, the CTO. More particularly, needle component <NUM> is distally advanced relative to outer shaft component <NUM> (as well as needle housing <NUM> housed within outer shaft component <NUM>) such that curved distal end <NUM> is no longer constrained by needle housing <NUM> but rather is extended to protrude from side port <NUM> of outer shaft component <NUM>. When released from needle housing <NUM>, curved distal end <NUM> resumes its pre-formed shape or geometry by its own internal restoring forces. As described with respect to <FIG>, curved distal end <NUM> extends, bends, or otherwise curves in a circular path, thereby forming a portion of a circle having a radius R. When needle component <NUM> is distally advanced or extended as in <FIG>, distal tip <NUM> may be used to penetrate through the vessel wall and re-enter a true lumen of a vessel. As described above, by forming the bend of curved distal end <NUM> of needle component <NUM> with the same curvature or radius as the bend of curved distal portion <NUM> of needle housing <NUM>, deployed needle component <NUM> is very stable inside needle housing <NUM>, thus minimizing any rotation or relative movement between the two components.

Reentry guidewire <NUM> may be advanced through lumen <NUM> of needle component <NUM> and into the true lumen TL of vessel V as shown in <FIG>. Reentry guidewire <NUM> has a relatively smaller outer diameter such as <NUM> in order to minimize the size of needle component <NUM> and subsequently, minimize the size of occlusion bypassing apparatus <NUM>. Additionally, occlusion bypassing apparatus <NUM> may be removed and reentry guidewire <NUM> may be left in place as shown in <FIG>, with reentry guidewire <NUM> extending in true lumen TL proximal to the CTO, through the subintimal tract, and back into true lumen TL distal to the CTO such that the CTO may now be successfully crossed via the pathway or conduit thus created.

Additionally, a covered or uncovered stent may be delivered over reentry guidewire <NUM> and implanted within the subintimal tract to facilitate flow from the lumen of the vessel upstream of the CTO, through the subintimal tract and back into the lumen of the vessel downstream of the CTO. <FIG> shows a distal end of a catheter <NUM> having a stent <NUM> mounted thereon being advanced over reentry guidewire <NUM> to a position where a distal end <NUM> of the radially collapsed stent <NUM> is in true lumen TL of vessel V downstream of chronic total occlusion CTO, a proximal end <NUM> of stent <NUM> is in true lumen TL of vessel V upstream of chronic total occlusion CTO, and a tubular body of stent <NUM> extends through the subintimal tract. Stent <NUM> is then deployed by either self-expansion or balloon inflation within the subintimal reentry tract to dilate the subintimal tract and compress the adjacent chronic total occlusion CTO. Stent <NUM> provides a scaffold which maintains the subintimal tract in an open condition capable of carrying blood downstream of chronic total occlusion CTO. Thereafter, reentry guidewire <NUM> and catheter <NUM> may be removed from the patient, leaving stent <NUM> in an expanded configuration and creating a radially supported, subintimal blood flow channel around chronic total occlusion CTO as seen in <FIG>. In some cases, it may be desirable to enlarge the diameter of the subintimal tract before advancing stent catheter <NUM> into and through it. Such enlargement of the subintimal tract may be accomplished by passing a balloon catheter over reentry guidewire <NUM> and inflating the balloon to dilate the tract, or may be any other suitable tract enlarging, dilating or de-bulking instrument that may be passed over reentry guidewire <NUM>.

Claim 1:
An apparatus (<NUM>) for bypassing an occlusion in a blood vessel comprising:
an outer shaft component (<NUM>) having a side port (<NUM>) proximal to a distal end (<NUM>) thereof, the outer shaft component (<NUM>) including a needle lumen (<NUM>) there-through that includes a curved distal portion that bends from a longitudinal axis of the apparatus and terminates at the side port (<NUM>) of the outer shaft component (<NUM>) and an inflation lumen (<NUM>) there-through configured to receive inflation fluid;
a needle component (<NUM>) configured to be slidably disposed within the needle lumen (<NUM>) of the outer shaft component (<NUM>) and removable therefrom; and
an inflatable balloon (<NUM>) disposed at the distal end (<NUM>) of the outer shaft component (<NUM>) and in fluid communication with the inflation lumen (<NUM>) of the outer shaft component (<NUM>), the balloon (<NUM>) including a body portion (<NUM>) that is disposed distal to the side port (<NUM>) of the outer shaft component (<NUM>), the body portion (<NUM>) of the balloon (<NUM>) having a flattened profile in an inflated state with first and second chambers (122A, 122B) that laterally extend from opposing sides of the outer shaft component (<NUM>) for stabilizing the apparatus within a subintimal space.