Patent Description:
Aspects of the present disclosure relate to guide catheter systems for accessing intravascular target sites, guide extension catheters useful with such systems.

Arteries of the heart, and more specifically coronary arteries, may sometimes be occluded or narrowed by atherosclerotic plaques or other lesions. These afflictions are generally referred to as coronary heart disease or stenosis, and result in inadequate blood flow to distal arteries and tissue. Heart bypass surgery may be a viable surgical procedure for certain patients suffering from coronary heart disease. However, traditional open heart surgery may inflict significant patient trauma and discomfort, and may require extensive recuperation times. Further, life threatening complications may occur due to the invasive nature of the surgery and the necessity for stoppage of the heart during such a surgery.

To address these concerns, efforts have been made to perform interventional cardiology procedures using minimally invasive techniques. In an example, percutaneous transcatheter (or transluminal) delivery and implantation of interventional coronary device are employed to overcome the problems presented by traditional open heart surgery. In such a procedure, a guide catheter is first interested through an incision into a femoral (transfemoral) or radial (transradial) artery of a patient. For example, the Seldinger technique may be utilized in either method for percutaneously introducing the guide catheter. In such methods, the guide catheter is advanced through the aorta and inserted into the opening of an ostium of a coronary artery. A guidewire, or other interventional coronary device, such as a catheter-mounted stent and/or balloon catheter, may be introduced through the guide catheter and maneuvered/advanced through the vasculature and the stenosis of the diseased coronary artery. However, when attempting to pass through a difficult stenosis, or when conducting a radial intervention using a small diameter guide catheter, the guide catheter may not have adequate back support, and continued application of force to advance the interventional coronary device through the stenosis may cause the distal end of the guide catheter to dislodge from the opening of the ostium of the coronary artery, resulting in potential damage to the surrounding tissue.

In order to prevent the guide catheter from dislodging, interventional cardiologists sometimes would deep seat the guide catheter into the coronary artery. The term "deep seat" or "deep seating" means that the guide catheter would be pushed farther downstream into the coronary artery. However, deep seating the guide catheter may risk the guide catheter damaging the coronary artery wall (e.g., dissection or rupture), occluding the coronary artery, or interfering with blood flow to the coronary artery.

One attempt to provide additional support to a guide catheter that has gained acceptance is the use of a guide extension catheter. Examples of guide extension catheters can be found in documents <CIT> or <CIT>. The guide extension catheter is deployed within a lumen of the guide catheter and extends distally from the distal end of the guide catheter into the coronary artery. Their smaller size, as compared to the guide catheter, allows the guide extension catheter to be seated more deeply in the coronary artery with less potential damage. The guide extension catheter provides additional support to the guide catheter to aid in delivery of interventional coronary devices. In cases with a difficult stenosis or radial interventions, the use of the guide extension catheter may reduce the risk of the guide catheter dislodging from the opening of the ostium of the coronary artery during treatment.

Some aspects of the present disclosure related to a guide extension catheter assembly according to claim <NUM> including a guide extension catheter and a support device. The guide extension catheter includes a shaft and a tubular member. The tubular member defines a proximal end opposite a distal end, and a lumen open to the proximal and distal ends. The shaft is coupled to the tubular member at the proximal end and extends proximally from the proximal end. The support device includes a push member and a shuttle member. The shuttle member defines a leading end opposite a trailing end. The push member is coupled to the shuttle member at the trailing end and extends proximally from the trailing end. The guide extension catheter assembly is configured to selectively provide a delivery state in which at least a portion of the shuttle member is disposed within the lumen, the leading end is distal the distal end, and the shuttle member is directly, physically connected to the tubular member. In the delivery state, a longitudinal distal force applied to the push member is transferred to the tubular member as a longitudinal distal force via the shuttle member. The guide extension catheter assemblies of the present disclosure can promote a two stage guide extension catheter deployment; the shuttle member promotes delivery of the tubular member and can then be removed with the tubular member then facilitating guide extension catheter procedures. In some embodiments, the guide extension catheter assembly includes complementary connection features that selectively provide direct, physical connection between the tubular member and the shuttle member. In some embodiments, the tubular member defines a plurality of perfusion holes and/or other features conducive to guide extension catheter procedures.

Other aspects of the present disclosure are directed toward a coronary treatment system including a guide catheter, a guide extension catheter assembly, and an interventional coronary device. The guide extension catheter assembly includes a guide extension catheter and a support device. The guide extension catheter includes a shaft and a tubular member. The tubular member defines a proximal end opposite a distal end, and a lumen open to the proximal and distal ends. The shaft is coupled to the tubular member at the proximal end and extends proximally from the proximal end. The support device includes a push member and a shuttle member. The shuttle member defines a leading end opposite a trailing end. The push member is coupled to the shuttle member at the trailing end and extends proximally from the trailing end. The guide extension catheter assembly is configured to selectively provide a delivery state in which at least a portion of the shuttle member is disposed within the lumen, the leading end is distal the distal end, and the shuttle member is directly, physically connected to the tubular member. In the delivery state, a longitudinal distal force applied to the push member is transferred to the tubular member as a longitudinal distal force via the shuttle member. In some embodiments, the guide catheter defines a lumen through sized to slidably receive the tubular member and the shuttle member in the delivery state, as well as a working end of the interventional coronary device. In other embodiments, the system further includes a guidewire in addition to the interventional coronary device.

Yet other aspects of the present disclosure are directed toward methods (not claimed) of percutaneously accessing an intravascular target region. The methods include positioning a distal side of a guide catheter adjacent to an ostium of a target vessel. A guide extension catheter assembly is arranged to a delivery state. The guide extension catheter assembly includes a guide extension catheter and a support device. The guide extension catheter includes a shaft and a tubular member. The tubular member defines a proximal end opposite a distal end, and a lumen open to the proximal and distal ends. The shaft is coupled to the tubular member at the proximal end and extends proximally from the proximal end. The support device includes a push member and a shuttle member. The shuttle member defines a leading end opposite a trailing end. The push member is coupled to the shuttle member at the trailing end and extends proximally from the trailing end. The delivery state includes at least a portion of the shuttle member disposed within the lumen, the leading end distal the distal end, and the shuttle member directly, physically connected to the tubular member. In the delivery state, a longitudinal distal force applied to the push member is transferred to the tubular member as a longitudinal distal force via the shuttle member. The guide extension catheter assembly is advanced in the delivery state through the guide catheter such that at least a region of the tubular member projects distally beyond the distal side of the guide catheter. The guide extension catheter assembly is transitioned from the delivery state, including removing the support device from the guide extension catheter. An interventional coronary device (e.g., a catheter-based device carrying a stent) is then advanced through the guide catheter and the tubular member. In some embodiments, the methods further include used of a guidewire to direct one or more of the guide catheter and the guide extension catheter assembly.

Specific embodiments of the present disclosure 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 present disclosure with respect to a position or direction relative to the treating clinician. "Distal" or "distally" refer to positions distant from or in a direction away from the clinician. "Proximal" and "proximally" refer to positions near or in a direction toward the clinician.

One embodiment of a guide extension catheter assembly <NUM> in accordance with principles of the present disclosure and useful with systems and methods of the present disclosure is shown in <FIG> and <FIG>, and includes a guide extension catheter <NUM> and a support device <NUM>. Details on the various components are provided below. In general terms, the guide extension catheter <NUM> includes a tubular member <NUM>, and the support device <NUM> includes a shuttle member <NUM>. In a delivery state of the guide extension catheter assembly <NUM> reflected by <FIG>, the shuttle member <NUM> is disposed within the tubular member <NUM>, and can promote delivery or advancement of the guide extension catheter assembly <NUM> through a tortuous path (e.g., vasculature). Once a desired location has been attained, the shuttle member <NUM> can be removed from the tubular member <NUM>, and the guide extension catheter <NUM> is available for other procedural steps. For example, the tubular member <NUM> can serve as an extension of a conventional guide catheter. With some guide extension catheter assemblies <NUM> of the present disclosure, attributes conducive to intravascular traversal can be incorporated into a design of the support device <NUM> (e.g., hoop strength, longitudinal push strength, etc.), whereas attributes conducive to guidance and delivery of an interventional coronary device (not shown) can be incorporated into a design of the guide extension catheter <NUM>. In some embodiments, complementary connection features are provided that provide direct, physical connection between the tubular member <NUM> and the shuttle member <NUM> in the delivery state as described below.

The guide extension catheter <NUM> can assume various forms, and includes the tubular member <NUM> and a shaft <NUM>. As described below, the shaft <NUM> is coupled to, and extends proximally from, the tubular member <NUM>. As a point of reference, in some non-limiting embodiments the guide extension catheter <NUM> can have a length on the order of <NUM> centimeters (cm), with the tubular member <NUM> being approximately <NUM> - <NUM> in length. However, this is not meant to limit the present disclosure, and the guide extension catheter <NUM> and/or the tubular member <NUM> thereof may be longer or shorter.

With reference between <FIG> and <FIG>, the tubular member <NUM> defines a proximal end <NUM> opposite a distal end <NUM>, and a lumen <NUM> open at the proximal and distal ends <NUM>, <NUM>. The lumen <NUM> is sized to receive a device, such as an interventional coronary device (not shown) as described below, for guiding the device along a longitudinal axis A of the tubular member <NUM>. Further, an outer diameter ODT of the tubular member <NUM> can be selected in accordance with a desired end use as described below (e.g., the outer diameter ODT can be selected such that the tubular member <NUM> can be slidably received within a guide catheter being employed with a particular end use procedure).

The tubular member <NUM> can be formed of various materials, non-limiting examples of which include polymers and braided polymers. In the representation of <FIG>, a structure of the tubular member <NUM> is illustrated as being defined by a wall <NUM>. The wall <NUM> can have a homogenous or monolithic construction as shown. In other embodiments, the wall <NUM> can be collectively formed by two or more continuous or discontinuous layers (e.g., an inner liner and outer jacket sandwiching one or more wires or other reinforcement bodies). Regardless, the wall <NUM> has a wall thickness TT and provides the tubular member <NUM> with physical attributes including hoop strength and longitudinal column rigidity or stiffness (i.e., extent to which the tubular member <NUM> resists deformation when subjected to a force along the longitudinal axis A).

In some embodiments, the tubular member <NUM> can be designed to incorporate attributes conducive to use of the tubular member <NUM> as an extension of a conventional guide catheter; in related embodiments, a design of the tubular member <NUM> need not directly account for or consider deliverability through a tortuous intravascular path (e.g., the tubular member <NUM> does not need to have or exhibit a hoop strength and/or longitudinal column rigidity normally considered necessary for intravascular delivery) due to provision of the support device <NUM> as described below. Thus, in some embodiments, the wall thickness TT can be less than the wall thickness conventionally employed with guide extension catheters. Along these same lines, <FIG> illustrates another tubular member <NUM>' useful with the assemblies, systems and methods of the present disclosure. The tubular member <NUM>' is akin to the tubular member <NUM> (<FIG>) described above, and includes the wall <NUM>. In addition, a plurality of perfusion holes <NUM> are defined by or formed in the wall <NUM>. The perfusion holes <NUM> can have wide variety of shapes and sizes, and can be formed in a number of different patterns. In general terms, the perfusion holes <NUM> are open to the lumen <NUM> (<FIG>) and are configured to aid in continuous perfusion during use of the tubular member <NUM>' as an extension of a conventional guide catheter. Although presence of the perfusion holes <NUM> might otherwise negatively affect deliverability of the tubular member <NUM>' as a standalone device, the support device <NUM> (<FIG>) serves to facilitate delivery of the tubular member <NUM>'. Other features can be incorporated into the tubular member <NUM>' that enhance performance as an extension of a conventional guide catheter.

Returning to <FIG> and <FIG>, the shaft <NUM>, also referred to as a pushwire or push member, defines a proximal side <NUM> opposite a distal side <NUM>. The distal side <NUM> is coupled to the tubular member <NUM> in a region of the proximal end <NUM>, and the shaft <NUM> is arranged to extend proximally from the tubular member <NUM> to the proximal side <NUM>. The shaft <NUM> may be formed of materials such as, but not limited to, stainless steel, nickel-titanium alloys (e.g., NITINOL), high performance alloys that are cobalt, chromium, molybdenum and/or nickel based (e.g., MP35N, L605, ELGILOY), or other materials suitable for the purposes described herein.

In some embodiments, the shaft <NUM> can be a solid body (e.g., a solid wire). In other embodiments, an internal passage can be defined along a portion or an entirety of the shaft <NUM>. In some embodiments, the shaft <NUM> can have a uniform cross-sectional shape (e.g., circular, square, etc.) from the proximal side <NUM> to the distal side <NUM>. In other embodiments, one or more variations in cross-sectional shape can be incorporated into the shaft <NUM> along a length thereof (e.g., the shaft <NUM> can have a varying thickness, the shaft <NUM> can have a more flattened shape proximate the tubular member <NUM>, etc.). Regardless, a maximum outer dimension ODSHAFT of the shaft <NUM> is less than the outer diameter ODT (<FIG>) of the tubular member <NUM>.

Coupling of the shaft <NUM> with the tubular member <NUM> can assume various forms appropriate for providing a robust connection. For example, in some non-limiting embodiments, a segment of the shaft <NUM>, including the distal side <NUM>, can be embedded into a thickness of the tubular member <NUM>. Alternatively, the shaft <NUM> can be secured (e.g., bonded) to an exterior or interior surface of the tubular member <NUM>. In yet other embodiments, a connecting member (not shown) can be provided that secures the shaft <NUM> relative to the tubular member <NUM>. For example, the shaft <NUM> can be attached to a collar that in turn is secured over an exterior of the tubular member <NUM>.

With specific reference to <FIG>, the support device <NUM> can assume various forms, and includes the shuttle member <NUM> and a push member <NUM>. As described below, the push member <NUM> is coupled to, and extends proximally from, the shuttle member <NUM>. As a point of reference, in some non-limiting embodiments the support device <NUM> can have a length on the order of <NUM>, with the shuttle member <NUM> being approximately <NUM> - <NUM> in length (and optionally slightly longer than the tubular member <NUM>. However, this is not meant to limit the present disclosure, and the support device <NUM> and/or the shuttle member <NUM> thereof may be longer or shorter.

With reference between <FIG> and <FIG>, the shuttle member <NUM> defines a leading end <NUM> opposite a trailing end <NUM>, and a passageway <NUM> (referenced generally in <FIG>). The passageway <NUM> is sized to receive a device, such as guidewire (not shown) as described below, and can be open to an exterior of the shuttle member <NUM> at the leading end <NUM> and in a region of the trailing end <NUM> for guiding the device along a longitudinal axis B of the shuttle member <NUM>.

The shuttle member <NUM> can be a continuous, homogenous body in some embodiments. In other embodiments, the shuttle member <NUM> can include two or more sections that are separately formed and subsequently assembled. Regardless, an interface region <NUM> of the shuttle member <NUM> includes, and extends proximally from, the leading end <NUM>. The interface region <NUM> has a length (i.e., dimension in a direction parallel with the longitudinal axis B) that is not less than a length of the tubular member <NUM>, and defines a maximum outer dimension (e.g., outer diameter) ODs in a direction transverse to the longitudinal axis B. The maximum outer dimension ODs corresponds with (e.g., is slightly less than) a size or diameter of the tubular member lumen <NUM> (<FIG>) such that the interface region <NUM> is configured to be readily received within the tubular member <NUM>. In some embodiments, one or more portions of the shuttle member <NUM> proximal the interface region <NUM> can have an outer dimension greater than the maximum outer dimension ODs as described below. With these and similar constructions, however, the maximum outer dimension ODs can be identified along the shuttle member <NUM> from the leading end <NUM> to a location not less than a length of the tubular member <NUM>. In other embodiments, an entirety of the shuttle member <NUM> has a maximum outer dimension approximating (e.g., slightly less than) a size or dimeter of the tubular member lumen <NUM>.

In some embodiments, the interface region <NUM> includes or is defined by a support section <NUM> and an optional tip section <NUM>. The support section <NUM> is configured to receive and support the tubular member <NUM>. For example, the support section <NUM> has a length (i.e., dimension in a direction parallel with the longitudinal axis B) that is not less than a length of the tubular member <NUM>, and has a substantially uniform (i.e., within <NUM> percent of a truly uniform construction) exterior shape and size in a direction of the length of the shuttle member <NUM>. In some embodiments, the support section <NUM> can define a circular exterior shape in transverse cross-section as shown in <FIG>, although other shapes are acceptable. Regardless, the support section <NUM> defines the maximum outer dimension (e.g., outer diameter) ODs.

The support section <NUM>, optionally an entirety of the shuttle member <NUM>, can be formed of various materials, non-limiting examples of which include polymers (e.g., thermoplastic elastomer such as a polyether block amide thermoplastic elastomer available from Arkema of Colombes, FR under the tradename PEBAX®) and braided polymers. In the representation of <FIG>, a structure of the support section <NUM> is illustrated as being defined by a wall <NUM>. The wall <NUM> can have a homogenous or monolithic construction as shown. In other embodiments, the wall <NUM> can be collectively formed by two or more continuous or discontinuous layers (e.g., an inner liner and outer jacket sandwiching one or more wires or other reinforcement bodies). Regardless, the wall <NUM> has a wall thickness Ts and provides the shuttle member <NUM> with physical attributes including hoop strength and longitudinal column rigidity or stiffness (i.e., extent to which the shuttle member <NUM> resists deformation when subjected to a force along the longitudinal axis B). In some embodiments, the shuttle member <NUM>, and in particular at least the support section <NUM>, incorporates one or more features or attributes that render the shuttle member <NUM> more conducive to intravascular delivery as compared to the tubular member <NUM>. For example, in some embodiments, the wall thickness Ts of the shuttle member <NUM> (at least along the support section <NUM>) is greater than the wall thickness TT (<FIG>) of the tubular member <NUM>, for example at least <NUM>% greater. Alternatively or in addition, a hoop strength of the shuttle member <NUM> along at least the support section <NUM> can be greater than the hoop strength of the tubular member <NUM>, for example at least <NUM>% greater. Alternatively or in addition, a longitudinal column rigidity or stiffness (i.e., extent to which the shuttle member <NUM> resists deformation when subjected to a force along the longitudinal axis B) of the shuttle member <NUM> along at least the support section <NUM> can be greater than the longitudinal column rigidity or stiffness of the tubular member <NUM>. While the support section <NUM> is generally illustrated as having a shape akin to the shape of the tubular member <NUM> (e.g., circular shape in transverse cross-section), other formats are also acceptable. For example, an outer or perimeter shape of the support section <NUM> in transverse cross-section can include one or more linear segments (e.g., square, hexagonal, etc.), can have an irregular shape, etc..

Where provided, the tip section <NUM> tapers in the proximal direction from the support section <NUM> to the leading end <NUM>, such that the tip section <NUM> promotes atraumatic interface with tissue. The atraumatic attributes of the tip section <NUM> can be further enhanced by forming the tip section <NUM> from a material differing from that of the support section <NUM>; for example, a material of the tip section <NUM> can be a softer and/or more compliant than a material of the support section <NUM>. In other embodiments, the shuttle member <NUM> need not include a tapered tip (e.g., the leading end <NUM> has the maximum outer dimension ODs).

Regardless of whether the shuttle member <NUM> includes a tapered tip, in some non-limiting embodiments, the shuttle member <NUM> can optionally further include or define a trailing region <NUM> extending proximally from the interface region <NUM>. The trailing region <NUM> may have an exterior size and/or shape differing from that of the interface region <NUM>, and in particular differing from the support section <NUM> (e.g., a portion of the trailing region <NUM> can have an outer dimension or diameter greater than the maximum outer dimension ODs of the support section <NUM>, can taper distally to the trailing end <NUM>, etc.).

The push member <NUM>, also referred to as a pushwire or a shaft, defines a leading side <NUM> opposite a trailing side <NUM>. The leading side <NUM> is coupled to the shuttle member <NUM> in a region of the trailing end <NUM>, and the push member <NUM> is arranged to extend proximally from the shuttle member <NUM> to the trailing side <NUM>. The push member <NUM> may be formed of materials such as, but not limited to, stainless steel, nickel-titanium alloys (e.g., NITINOL), high performance alloys that are cobalt, chromium, molybdenum and/or nickel based (e.g., MP35N, L605, ELGILOY), or other materials suitable for the purposes described herein.

In some embodiments, the push member <NUM> can be a solid body (e.g., a solid wire). In other embodiments, an internal passage can be defined along a portion or an entirety of the push member <NUM>. In some embodiments, the push member <NUM> can have a uniform cross-sectional shape (e.g., circular, square, etc.) from the leading side <NUM> to the trailing side <NUM>. In other embodiments, one or more variations in cross-sectional shape can be incorporated into the push member <NUM> along a length thereof (e.g., the push member <NUM> can have a varying thickness, the push member <NUM> can have a more flattened shape proximate the shuttle member <NUM>, etc.). Regardless, a maximum outer dimension ODR of the push member <NUM> is less than the maximum outer dimension ODs of the shuttle member <NUM>.

Coupling of the push member <NUM> with the shuttle member <NUM> can assume various forms appropriate for providing a robust connection. For example, in some non-limiting embodiments, a segment of the push member <NUM>, including the leading edge <NUM>, can be embedded into the shuttle member <NUM>. Alternatively, the push member <NUM> can be secured (e.g., bonded) to an exterior or interior surface of the shuttle member <NUM>. In yet other embodiments, a connecting member (not shown) can be provided that secures the push member <NUM> relative to the shuttle member <NUM>. For example, the push member <NUM> can be attached to a collar that in turn is secured over an exterior of the shuttle member <NUM> (with the collar optionally being considered as a part or component of the shuttle member <NUM> (e.g., the trailing region <NUM>)).

The push member <NUM> can be arranged relative to the shuttle member <NUM> in various manners. For example, <FIG> illustrates that in some non-limiting embodiments, the push member <NUM> can be approximately centered with or axially aligned with the shuttle member <NUM>. <FIG> further reflects that with these and other embodiments, the passageway <NUM> can be non-linear across a length of the shuttle member <NUM>. Another example support device <NUM>' is shown in <FIG> and includes a shuttle member <NUM>' and a push member <NUM>' akin to the descriptions above. The shuttle member <NUM>' defines a passageway <NUM>' (e.g., for slidably receiving a guidewire (not shown) that is linear across a length of the shuttle member <NUM>'. The push member <NUM>' extends proximally from the shuttle member <NUM>' and is off-set from central or longitudinal axis of the shuttle member <NUM>'. Other relationships between the shuttle member <NUM>', the push member <NUM>' and the passageway <NUM>' are also envisioned.

The guide extension catheter assembly <NUM> is transitioned to the delivery state of <FIG> by directing the leading end <NUM> of the shuttle member <NUM> into the lumen <NUM> (<FIG>) of the tubular member <NUM> at the proximal end <NUM>. The shuttle member <NUM> is then advanced distally relative to the tubular member <NUM> (and/or the tubular member <NUM> retracted proximally relative to the shuttle member <NUM>), locating a length of the tubular member <NUM> over the shuttle member <NUM>. Advancement and/or manipulation of the tubular member <NUM> and the shuttle member <NUM> relative to one another continues until the delivery state arrangement is achieved in which the leading end <NUM> of the shuttle member <NUM> is distal the distal end <NUM> of the tubular member <NUM>, and the shuttle member <NUM> is directly, physically connected to the tubular member <NUM>. In the delivery state, a longitudinal distal force applied to the push member <NUM> is transferred to the tubular member <NUM> as a longitudinal distal force via the shuttle member <NUM>. As described in greater detail below, in some embodiments the tubular member <NUM> and the shuttle member <NUM> incorporate complimentary connection features that provide the direct, physical connection. Thus, in some embodiments and as reflected in <FIG>, the tubular member <NUM> may be generally disposed over the shuttle member <NUM> but with sufficient clearance to allow for relatively easy withdrawal of the shuttle member <NUM> from the tubular member <NUM> when desired; with these and other embodiments, the complementary connection features provide the direct, physical connection between the tubular member <NUM> and the shuttle member <NUM> in a manner that provides an at least one directional "lock" between the tubular member <NUM> and the shuttle member <NUM> (e.g., in the delivery state, the tubular member <NUM> and the shuttle member <NUM> are locked relative to one another such that the shuttle member <NUM> cannot be further distally advanced relative to the tubular member <NUM> from the arrangement of <FIG>). Regardless, in the delivery state, the shuttle member <NUM> supports the tubular member <NUM>, providing physical and/or mechanical properties that promote ease of intravascular deliverability (and which physical and/or mechanical properties are not fully provided by the tubular member <NUM> in and of itself).

<FIG> depicts the tubular member <NUM> and the shuttle member <NUM> arranged in the delivery state, and further illustrates one example of complementary connection features in accordance with principles of the present disclosure. In particular, the shuttle member <NUM> includes or carries a shoulder <NUM>, and the proximal end <NUM> of the tubular member <NUM> is sized and shaped to abut the shoulder <NUM> with distal insertion of the shuttle member <NUM> through the lumen <NUM>. For example, an outer dimension or diameter of the support section <NUM> of the shuttle member <NUM> can approximate or be slightly less than a diameter of the lumen <NUM>; the shoulder <NUM> extends radially outward from the support section <NUM> to an outer dimeter greater than the diameter of lumen <NUM> and approximating an outer diameter of the tubular member <NUM>. In the delivery state, the shoulder <NUM> directly, physically contacts the proximal end <NUM> to achieve or provide a direct, physical connection between the tubular member <NUM> and the shuttle member <NUM> in distal direction of the shuttle member <NUM> relative to the tubular member <NUM>. That is to say, the direct, physical connection provided by the complementary connection features of the embodiment of <FIG> is such that a longitudinal distal force applied to the push member <NUM> is directly transferred onto the tubular member <NUM> as a distal longitudinal force via the abutting interface between the proximal end <NUM> of the tubular member <NUM> and the shoulder <NUM> of the shuttle member <NUM>. Similarly, a longitudinal proximal force applied to the tubular member <NUM> (e.g., when encountering an anatomical structure during a delivery procedure) is directly transferred onto the shuttle member <NUM> via the abutting interface between the proximal end <NUM> of the tubular member <NUM> and the shoulder <NUM> of the shuttle member <NUM>. In the presence of forces normally expected during a delivery procedure, once in the delivery state, the tubular member <NUM> will not move proximally relative to the shuttle member <NUM>, and the shuttle member <NUM> will not move distally relative to the tubular member <NUM>. The guide extension catheter assembly <NUM> can be transitioned from the delivery state to a released state by applying a pulling force in the proximal direction onto the shuttle member <NUM> while holding the tubular member <NUM> stationary. In the released state, the shuttle member <NUM> is free of direct, physical connection with the tubular member <NUM>.

Portions of an alternative guide extension catheter assembly <NUM> are shown in <FIG> and illustrate another example of complementary connection features of the present disclosure. The guide extension catheter assembly is <NUM> is arranged in a delivery state and includes a tubular member <NUM> and a shuttle member <NUM>. The tubular member <NUM> and the shuttle member <NUM> can have any of the forms described in the present disclosure. In this regard, the tubular member <NUM> defines a proximal end <NUM> and a lumen <NUM> bounded by an interior face <NUM>. The shuttle member <NUM> includes a support section <NUM> and a trailing region <NUM>. The support section <NUM> defines a support surface <NUM> sized and shaped to be slidably received within the lumen <NUM> as described above. The trailing region <NUM> defines a ramp surface <NUM> and a shoulder <NUM>. The ramp surface <NUM> extends proximally from the support surface <NUM>, expanding in diameter toward the shoulder <NUM>. Thus, an outer dimension or diameter of the ramp surface <NUM> increases or expands in the proximal direction, from a diameter less than a diameter of the lumen <NUM> at the support surface <NUM> to a diameter greater than the diameter of the lumen <NUM> adjacent the shoulder <NUM>. An outer dimension or diameter of the shoulder <NUM> can approximate or be greater than an outer diameter of the tubular member <NUM>.

The complimentary connection features associated with the guide extension catheter assembly <NUM> include a configuration of a diameter of the lumen <NUM> at or proximate the proximal end <NUM>, along with the ramp surface <NUM>. With initial insertion of the shuttle member <NUM> into the lumen <NUM> via the proximal end <NUM>, the shuttle member <NUM> is readily distally advanced relative to the tubular member <NUM> due to clearance between the interior face <NUM> and the support surface <NUM>. As the ramp surface <NUM> enters the lumen <NUM>, the ramp surface <NUM> is brought into direct, physical contact with the interior face <NUM> along those regions of the ramp surface <NUM> having a diameter greater than the diameter of the lumen <NUM>. In the delivery state illustrated in FIG. 6B, a tapered fit or connection between the ramp surface <NUM> of the shuttle member <NUM> and the interior face <NUM> of the tubular member <NUM> has been obtained. In some embodiments, a material of the tubular member <NUM> compresses in response to forces exerted thereon by the ramp surface <NUM> with distal advancement of the shuttle member <NUM> relative to the tubular member <NUM>. In other embodiments, a slight taper can be incorporated into a design of the tubular member <NUM> at the proximal end <NUM>, with this taper angle approximating a taper angle of the ramp surface <NUM>.

The direct, physical connection provided by the complementary connection features of the embodiment of <FIG> is such that a longitudinal distal force applied to the push member <NUM> (otherwise attached to the shuttle member <NUM>) is directly transferred onto the tubular member <NUM> as a distal longitudinal force via the abutting interface between the interior face <NUM> of the tubular member <NUM> and the ramp surface <NUM> of the shuttle member <NUM>. Similarly, a longitudinal proximal force applied to the tubular member <NUM> (e.g., when encountering an anatomical structure during a delivery procedure) is directly transferred onto the shuttle member <NUM> via the abutting interface between the interior face <NUM> of the tubular member <NUM> and the ramp surface <NUM> of the shuttle member <NUM>. In the presence of forces normally expected during a delivery procedure, once in the delivery state, the tubular member <NUM> will not move proximally relative to the shuttle member <NUM>, and the shuttle member <NUM> will not move distally relative to the tubular member <NUM>. The guide extension catheter assembly <NUM> can be transitioned from the delivery state to a released state by applying a pulling force in the proximal direction onto the shuttle member <NUM> while holding the tubular member <NUM> stationary.

Portions of another alternative guide extension catheter assembly <NUM> are shown in <FIG> and illustrate another example of complementary connection features of the present disclosure. The guide extension catheter assembly is <NUM> is arranged in a delivery state and includes a tubular member <NUM> and a shuttle member <NUM>. The tubular member <NUM> can generally have any of the forms described in the present disclosure. In this regard, the tubular member <NUM> defines a proximal end <NUM> and a lumen (hidden). Further, a slot <NUM> is formed through a wall of the tubular member <NUM>, extending from and open to the proximal end <NUM>. The slot <NUM> can have a first segment <NUM> and a second segment <NUM>. In some embodiments, the first segment <NUM> extends from the proximal end <NUM> in a generally longitudinal direction (e.g., parallel with a central longitudinal axis of the tubular member <NUM>). The second segment <NUM> extends from the first segment <NUM> opposite the proximal end <NUM>, defining a non-parallel angle relative to the first segment <NUM>. For example, an angle defined by the first and second segments <NUM>, <NUM> can be in the range of approximately <NUM> - <NUM> degrees, and in some embodiments, the second segment <NUM> extends in a circumferential fashion relative to a circumference of the tubular member <NUM>.

The shuttle member <NUM> can generally have any of the forms described in the present disclosure. In this regard, the shuttle member <NUM> includes a support section <NUM> defining a support surface <NUM> and a post <NUM>. The support surface <NUM> is sized and shaped to be slidably received within the lumen (not shown) of the tubular member <NUM> as described above. The post <NUM> projects radially outwardly from the support surface <NUM> and is sized and shaped to be slidably received within the slot <NUM>.

The complimentary connection features associated with the guide extension catheter assembly <NUM> include a configuration of the slot <NUM> and the post <NUM>. With initial insertion of the shuttle member <NUM> into the lumen (not shown) of the tubular member <NUM> via the proximal end <NUM>, the shuttle member <NUM> is readily distally advanced relative to the tubular member <NUM> due to clearance between the support surface <NUM> and the tubular member <NUM>. With continued distal advancement, as the post <NUM> approaches the proximal end <NUM>, the shuttle member <NUM> is rotationally oriented such that the post <NUM> is longitudinally aligned with the slot <NUM> at the proximal end <NUM>. With further distal advancement, then, the post <NUM> will enter the slot <NUM> and progress along the first segment <NUM>. Upon reaching the transition from the first segment <NUM> to the second segment <NUM>, the shuttle member <NUM> is rotated relative to the tubular member <NUM> such that the post <NUM> slides within the second segment <NUM> to the arrangement of <FIG>.

The direct, physical connection provided by the complementary connection features of the embodiment of <FIG> is such that a longitudinal distal force applied to the push member <NUM> (otherwise attached to the shuttle member <NUM>) is directly transferred onto the tubular member <NUM> as a distal longitudinal force via the abutting interface between a structure of the tubular member <NUM> surrounding the slot <NUM> and the post <NUM> of the shuttle member <NUM>. Similarly, a longitudinal proximal force applied to the tubular member <NUM> (e.g., when encountering an anatomical structure during a delivery procedure) is directly transferred onto the shuttle member <NUM> via the abutting interface between the tubular member <NUM> and the post <NUM> in a region of the slot <NUM>. In the presence of forces normally expected during a delivery procedure, once in the delivery state, the tubular member <NUM> will not move relative to the shuttle member <NUM>, and the shuttle member <NUM> will not move relative to the tubular member <NUM>. The guide extension catheter assembly <NUM> can be transitioned from the delivery state to a released state by reversing the above steps, such as rotating the shuttle member <NUM> relative to the tubular member <NUM> to move the post <NUM> to the first segment <NUM>, and then applying a pulling force in the proximal direction onto the shuttle member <NUM> while holding the tubular member <NUM> stationary.

The guide extension catheter assemblies of the present disclosure can be useful with a number of different procedures, such as procedures that entail percutaneously accessing an intravascular target region. With these and other procedures, the guide extension catheter assemblies of the present disclosure can be provided to a clinician as part of a coronary treatment system that further includes a guide catheter and an interventional coronary device. The guide catheter can have a conventional design. The interventional coronary device can be any device for treating, for example, an abnormal condition of a coronary artery, such as, but not limited to, a stenosis. Non-limiting examples of interventional coronary devices include guidewires, a catheter-based treatment device (e.g., a balloon catheter carrying an expandable stent, a catheter carrying a self-expanding stent, a fractional flow reserve (FFR) catheter), etc. In some embodiments, the coronary treatment systems of the present disclosure include at least one guidewire along with an additional or separate interventional coronary device that is not a guidewire.

With reference to <FIG>, some methods (not claimed) of the present disclosure can include delivering a treatment device to a desired treatment location, such as in a coronary artery CA that is accessed through the aorta AA. A guide catheter <NUM> can be utilized to access the aorta AA as shown. Generally, the guide catheter <NUM> includes a lumen sized to receive an auxiliary device or devices (e.g., a guide extension catheter assembly, an interventional coronary device, etc.). In some embodiments, a guidewire (not shown) can be deployed to assist in delivering the guide catheter <NUM> to the general arrangement of <FIG>. Regardless, the guide catheter <NUM> is arranged such that a distal side <NUM> thereof is at or adjacent an ostium O of the coronary artery CA.

A guide extension catheter assembly of the present disclosure is arranged into the delivery state and advanced through the guide catheter <NUM>. For example, <FIG> illustrates a portion of the guide extension catheter assembly <NUM> in the delivery state and being advanced within a lumen <NUM> of the guide catheter <NUM> that has otherwise been advanced through an intravascular passage <NUM> along with a guidewire <NUM>. The tubular member <NUM> is disposed over and supported by the shuttle member <NUM>, and the guidewire <NUM> is slidably received within the passageway <NUM> of the shuttle member <NUM>. Advancement of the guide extension catheter assembly <NUM> can be facilitated by a distal pushing forced applied by the clinician onto the push member <NUM>. In some embodiments, an additional distal pushing force can be applied onto the shaft <NUM>. Regardless, the shuttle member <NUM> provides mechanical and/or structural support to the tubular member <NUM> sufficient to facilitate delivery of the tubular member <NUM> through a tortuous intravascular pathway (e.g., the pathway <NUM> partially implicated by <FIG>).

With reference between <FIG> and <FIG>, distal advancement of the guide extension catheter assembly <NUM> relative to the guide catheter <NUM> continues, with the leading end <NUM> of the shuttle member <NUM> attaining and then advancing distally beyond the distal side <NUM> of the guide catheter <NUM>. The tubular member <NUM> and the shuttle member <NUM> thus pass through the ostium O and enter the coronary artery CA. The optional tapered tip section <NUM> of the shuttle member <NUM> promotes atraumatic contact with tissue/walls of the coronary artery. As reflected by <FIG>, distal advancement of the guide extension catheter assembly <NUM> continues until the tubular member <NUM> is located at a desired position relative to the guide catheter <NUM> and the coronary artery CA (e.g., a portion of the tubular member <NUM> is within the guide catheter <NUM> and a remainder of the tubular member <NUM> extends along the coronary artery CA).

With the tubular member <NUM> positioned as desired, the support device <NUM> is removed from the patient. For example, a proximal pulling force is applied by the clinician onto the push member <NUM> while at the same time a force resisting proximal movement is applied onto the shaft <NUM>. As a result, the shuttle member <NUM> is caused to retract proximally from the tubular member <NUM>, and the tubular member <NUM> remains relatively stationary relative to the guide catheter <NUM> and the coronary artery CA. Complete removal of the support device <NUM> is reflected by <FIG>, illustrating that the guide extension catheter <NUM>, and particular the tubular member <NUM>, has remained at the desired position.

The guide extension catheter <NUM> is then available to facilitate delivery of an interventional coronary device <NUM> as generally shown in <FIG>. With reference between <FIG> and <FIG>, the interventional coronary device <NUM> is delivered through the lumen <NUM> of the guide catheter <NUM> and then advanced through the lumen <NUM> of the tubular member <NUM>. A distal working end of the interventional coronary device <NUM> (e.g., a stent loaded over a balloon) is advanced distally beyond the distal end <NUM> of the tubular member <NUM>, and positioned as desired, for example to treat a stenosis <NUM>. <FIG> further reflects that in some embodiments, the tubular member <NUM> can include or define perfusion holes <NUM>.

The guide extension catheter assemblies, coronary treatment systems and methods of the present disclosure provide a marked improvement over previous designs. The shuttle member or delivery shuttle assists in navigating and delivering the guide extension catheter to the target site (e.g., diseased artery). Once in place, the delivery shuttle is removed and the guide extension catheter is left in place to facilitate delivery of additional devices such as a stent. As a purpose of the delivery shuttle is to deliver the guide extension catheter, it can be designed to maximize deliverability of the device, thus sacrificing the mechanical performance of the guide extension catheter if it was a standalone device. However, because the guide extension catheter is not a standalone device, it can be designed with specific or unique features well suited for a particular procedure such as multiple perfusion holes or a thinner wall to give a larger inner diameter/smaller outer diameter.

Claim 1:
A guide extension catheter assembly (<NUM>, <NUM>, <NUM>) comprising:
a guide extension catheter (<NUM>) including:
a shaft (<NUM>),
a tubular member (<NUM>, <NUM>', <NUM>, <NUM>) defining a proximal end (<NUM>, <NUM>, <NUM>) opposite a distal end (<NUM>) and a lumen (<NUM>, <NUM>) open to the proximal and distal ends,
wherein the shaft (<NUM>) is coupled to the tubular member (<NUM>, <NUM>', <NUM>, <NUM>) at the proximal end (<NUM>, <NUM>, <NUM>) and extends proximally from the proximal end (<NUM>, <NUM>, <NUM>); and
a support device (<NUM>) including:
a push member (<NUM>, <NUM>'),
a shuttle member (<NUM>, <NUM>', <NUM>, <NUM>) defining a leading end (<NUM>) opposite a trailing end (<NUM>),
wherein the push member (<NUM>, <NUM>') is coupled to the shuttle member (<NUM>, <NUM>', <NUM>, <NUM>) at the trailing end (<NUM>) and extends proximally from the trailing end (<NUM>);
wherein the guide extension catheter assembly (<NUM>, <NUM>, <NUM>) is configured to selectively provide a delivery state in which at least a portion of the shuttle member (<NUM>, <NUM>', <NUM>, <NUM>) is disposed within the lumen (<NUM>, <NUM>), the leading end (<NUM>) is distal the distal end (<NUM>), and the shuttle member (<NUM>, <NUM>', <NUM>, <NUM>) is directly, physically connected to the tubular member (<NUM>, <NUM>', <NUM>, <NUM>) such that a longitudinal distal force applied to the push member (<NUM>, <NUM>') is transferred to the tubular member (<NUM>, <NUM>', <NUM>, <NUM>) as a longitudinal distal force via the shuttle member (<NUM>, <NUM>', <NUM>, <NUM>).