Patent Description:
More particularly, the present invention pertains to stent delivery systems.

A wide variety of intracorporeal medical devices have been developed for medical use, for example, intravascular use. Some of these devices include stent delivery systems. These devices are manufactured by any one of a variety of different manufacturing methods and may be used according to any one of a variety of methods. Of the known stent delivery devices and methods for making and using the same, each has certain advantages and disadvantages. There is an ongoing need to provide alternative stent delivery devices as well as alternative methods for making and using stent delivery devices. <CIT> discloses all features of the introductory portion of claim <NUM>.

<CIT> discloses an intraluminal grafting system having a balloon catheter assembly, a capsule catheter assembly and capsule jacket assembly which is used for deploying in the vessel of an animal body a bifurcated graft having a plurality of attachment systems. The deployment catheters contain an ipsilateral capsule assembly, a contralateral capsule assembly and a distal capsule assembly, wherein the attachment systems of the bifurcated graft are disposed within the three capsule assemblies. A removable sheath of the capsule jacket assembly covers the bifurcated graft and capsule assemblies to provide a smooth transition along the length of the deployment catheters.

The subject-matter of the present invention is defined by the features of independent claim <NUM>. The invention provides stent delivery systems including a stent. Stent delivery systems and methods for making and using the same are disclosed.

An example stent delivery system may include an inner member having a proximal end. A sleeve may be coupled to the inner member adjacent to the proximal end. A deployment sheath may be disposed about the inner member. A gear rack assembly may be coupled to the deployment sheath. A stent may be disposed between the inner member and the deployment sheath. A handle may be coupled to the inner member and to the deployment sheath.

The handle may include an actuation member. The actuation member may be coupled to the gear rack assembly so that actuation of the actuation member shifts the longitudinal position of the gear rack assembly and the deployment sheath. An engagement mechanism may be coupled to the gear rack assembly. The engagement mechanism may be configured to engage the sleeve of the inner member so that proximal retraction of the gear rack assembly results in proximal retraction of the inner shaft.

The stent delivery system of the present invention includes an inner member having an enlarged proximal end and an atraumatic distal tip. A stent is disposed about the inner member. A deployment sheath is disposed about the inner member and the stent. A gear rack assembly is coupled to the deployment sheath. A handle is coupled to the inner member and to the deployment sheath. The handle includes a thumbwheel that is coupled to the gear rack assembly so that rotation of the thumbwheel proximally retracts the gear rack assembly and the deployment sheath. An engagement mechanism is coupled to the gear rack assembly. The engagement mechanism is configured to catch on the enlarged proximal end of the inner member after the deployment sheath is proximally retracted a distance, and proximally retract the inner member.

An example method for deploying a stent is also disclosed which includes providing a stent delivery system. The stent delivery system may include an inner member having an enlarged proximal end and an atraumatic distal tip. A stent may be disposed about the inner member. A deployment sheath may be disposed about the inner member and the stent. A gear rack assembly may be coupled to the deployment sheath. A handle may be coupled to the inner member and to the deployment sheath. The handle may include a thumbwheel that is coupled to the gear rack assembly so that rotation of the thumbwheel proximally retracts the gear rack assembly and the deployment sheath. An engagement mechanism may be coupled to the gear rack assembly. The engagement mechanism may be configured to catch on the enlarged proximal end of the inner member, after the deployment sheath is proximally retracted a first distance, and proximally retract the inner member. The method may also include advancing the stent delivery system through a body lumen to a position adjacent to an area of interest and rotating the thumbwheel to proximally retract the gear rack assembly the first distance. Retraction of the gear rack assembly the first distance may result in the engagement mechanism catching on the enlarged proximal end of the inner member.

The method may also include further rotating the thumbwheel to further proximally retract the gear rack assembly and to proximally retract the inner member.

The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present invention.

The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.

<FIG> illustrates an example stent delivery system <NUM>. System <NUM> may include an elongate shaft <NUM> and a handle <NUM> coupled to shaft <NUM>. In general, system <NUM> may be used to deliver a suitable stent, graft, endoprosthesis or the like to an area of interest within a body lumen of a patient. The body lumen may be a blood vessel located near the heart (e.g., within or near a cardiac vessel), within a peripheral vessel, within a neurological vessel, or at any other suitable location. Deployment of the stent may include the proximal retraction of a retraction sheath <NUM>, which overlies the stent. Retraction of sheath <NUM> may include the actuation of an actuation member <NUM> generally disposed at handle <NUM>. In the example illustrated in <FIG>, actuation member <NUM> is a thumb wheel that can be rotated by a clinician in order to accomplish proximal retraction of deployment sheath <NUM>. Numerous other actuation members are contemplated. A number of other structures and features of system <NUM> can be seen in <FIG> and are labeled with reference numbers. Additional discussion of these structures can be found below.

<FIG> illustrate at least some of the structural components that may be included as a part of system <NUM>. For example, system <NUM> may include an inner shaft or member <NUM> as illustrated in <FIG>. In at least some embodiments, inner member <NUM> may be a tubular structure and, thus, may include a lumen (not shown). The lumen may be a guidewire lumen that extends along at least a portion of the length of inner member <NUM>. Accordingly, system <NUM> may be advanced over a guidewire to the desired target location in the vasculature. In addition, or in alternative embodiments, the lumen may be a perfusion/aspiration lumen that allows portions, components, or all of system <NUM> to be flushed, perfused, aspirated, or the like.

Inner member <NUM> may include a stent receiving region <NUM> about which a stent (not shown, can be seen in <FIG>) may be disposed. The length and/or configuration of stent receiving region <NUM> may vary. For example, stent receiving region <NUM> may have a length sufficient for the stent to be disposed thereon. It can be appreciated that as the length of the stent utilized for system <NUM> increases, the length of stent receiving region <NUM> also increases.

Along or otherwise disposed adjacent stent receiving region <NUM> may be one or more perfusion ports <NUM>. Ports <NUM> may extend through the wall of inner member <NUM> such that fluid may be infused through the lumen of inner member <NUM> and may be flushed through ports <NUM>. This may be desirable for a number of reasons. For example, ports <NUM> may allow a clinician to evacuate air bubbles that may be trapped adjacent the stent by perfusing fluid through ports <NUM>. In addition, ports <NUM> may be used to aspirate fluid that may be disposed along inner member <NUM>. Ports <NUM> may also aid in sterilization and/or other preparatory processing steps that may be involved in preparing system <NUM> for sale.

A tip <NUM> may be attached to or otherwise disposed at the distal end of inner member <NUM>. Tip <NUM> may generally have a rounded or smooth shape that provides a generally atraumatic distal end to system <NUM>. For example, tip <NUM> may have a smooth tapered distal portion <NUM> that gently tapers. Tip may also include a proximal ridge <NUM> that is configured so that sheath <NUM> can abut therewith. Tip <NUM> may also include a tapered proximal portion <NUM>. Numerous other shapes and/or configurations are contemplated for tip <NUM>.

Tip <NUM> may also include one or more cutouts or flats <NUM> formed therein. For the purposes of this disclosure, flats <NUM> are understood to be cutouts or flattened portions of tip <NUM> where the outer dimension or profile of tip <NUM> is reduced. The name "flats" comes from the fact that these regions may have a somewhat "flat" appearance when compared to the remainder of tip <NUM>, which generally may have a rounded profile. The shape, however, of flats <NUM> is not meant to be limited to being flat or planar as numerous shapes are contemplated.

Flats <NUM> may allow for a gap or space to be defined between inner member <NUM> and deployment sheath <NUM> when sheath <NUM> abuts proximal ridge <NUM> of tip <NUM>. This gap may allow for fluid, for example perfusion fluid passed through ports <NUM>, to flow out from sheath <NUM>. Thus, flats <NUM> may be used in conjunction with ports <NUM> to allow portions or all of system <NUM> to be flushed or otherwise evacuated of air bubbles.

<FIG> illustrates inner member <NUM> with some additional structure of system <NUM>. In this figure, a stent <NUM> is disposed about inner member <NUM> (e.g., about stent receiving region <NUM> of inner member <NUM>). In some embodiments, stent <NUM> is a self-expanding stent. Accordingly, stent <NUM> may be biased to outwardly expand. Because of this, stent <NUM> may not be "loaded onto" inner member <NUM> in a strict sense but rather may be thought of as being disposed about or surrounding inner member <NUM>. Stent <NUM> may then be restrained within deployment sheath <NUM>. In alternative embodiments, however, stent <NUM> may be directly loaded onto inner member <NUM> via crimping or any other suitable mechanical holding mechanism.

An intermediate tube <NUM> may also be disposed over inner member <NUM>. In at least some embodiments, intermediate tube <NUM> may extend from a position adjacent to the proximal end of inner member <NUM> to a position proximal of the distal end of inner member <NUM>. Intermediate tube <NUM> may include a bumper <NUM>. In practice, bumper <NUM> may function by preventing any unwanted proximal movement of stent <NUM> during navigation and/or deployment of stent <NUM>.

Bumper <NUM> may have any suitable form. In some embodiments, bumper <NUM> may be defined by a relatively short tube or sleeve that is disposed about intermediate tube <NUM>. The material utilized for the sleeve may be the same or different from that of intermediate tube <NUM>. Intermediate tube <NUM> may have a tapered or otherwise smooth transition in outer diameter adjacent bumper <NUM>. For example, polymeric material may be disposed or reflowed adjacent bumper <NUM> (which may include disposing the polymeric material about a portion or all of bumper <NUM>) so as to define a gentle transition in outer diameter at bumper <NUM>. Other configurations are contemplated and may be utilized in alternative embodiments.

<FIG> illustrates additional structure of system <NUM>. Here deployment sheath <NUM> can be seen disposed over inner member <NUM>, intermediate tube <NUM>, and stent <NUM>. It can be appreciated that sheath <NUM> is configured to shift between a first position, for example as shown in <FIG>, where sheath <NUM> overlies stent <NUM> and a second position where sheath <NUM> is proximally retracted to a position substantially proximal of stent <NUM>. In general, the first position may be utilized during navigation of system <NUM> to the appropriate location within a body lumen and the second position may be used to deploy stent <NUM>.

Sheath <NUM> may include a flared portion <NUM> where the outer diameter of sheath <NUM> is increased. In portion <NUM>, the thickness of the tubular wall of sheath <NUM> may or may not be increased. Flared portion <NUM> may be desirable for a number of reasons. For example, flared portion <NUM> may allow sheath <NUM> to have an adequate inner dimension that is suitable so that sheath <NUM> may be disposed about stent <NUM> and bumper <NUM>.

In at least some embodiments, sheath <NUM> may include a reinforcing member <NUM> embedded or otherwise included therewith. Reinforcing member <NUM> may have any number of a variety of different configurations. For example, reinforcing member <NUM> may include a braid, coil, mesh, combinations thereof, or the like, or any other suitable configuration. In some embodiments, reinforcing member <NUM> may extend along the entire length of sheath <NUM>. In other embodiments, reinforcing member <NUM> may extend along one or more portions of the length of sheath <NUM>. For example, reinforcing member <NUM> may extend along flared portion <NUM>.

Sheath <NUM> may also include a radiopaque marker or band <NUM>. In general, marker band <NUM> may be disposed adjacent to the distal end <NUM> of sheath <NUM>. One or more additional marker bands <NUM> may be disposed along other portions of sheath <NUM> or other portions of system <NUM>. Marker band <NUM> may allow the distal end <NUM> of sheath <NUM> to be fluoroscopically visualized during advancement of system <NUM> and/or deployment of stent <NUM>.

<FIG> also illustrates the distal end <NUM> of sheath <NUM> abutting proximal ridge <NUM>. In this configuration, stent <NUM> can be flushed (e.g., to remove air bubbles) by infusing fluid through inner member <NUM> and through ports <NUM>. Because of flats <NUM>, fluid may be allowed to be flushed out of sheath <NUM> by passing through the gaps formed between inner member <NUM> and sheath <NUM> at flats <NUM>.

<FIG> illustrates a distal portion <NUM> of handle <NUM>. Here it can be seen that handle <NUM> is attached to an outer member <NUM>. Outer member <NUM> may be disposed about sheath <NUM> and extend along a portion of the length of sheath <NUM>. Thus, along at least a portion of the length of system <NUM>, system <NUM> may include four tubular structures that may be coaxially arranged - namely outer member <NUM>, deployment sheath <NUM>, intermediate tube <NUM>, and inner member <NUM>. In at least some embodiments, outer member <NUM> may provide system <NUM> with a number of desirable benefits. For example, outer member <NUM> may include or otherwise be formed from a lubricious material that can reduce friction that may be associated with proximally retracting sheath <NUM>. In addition, outer member <NUM> may comprise a surface that can be clamped or otherwise locked so that the position of system <NUM> can be maintained without negatively impacting the retraction of sheath <NUM> (which might otherwise be impacted if sheath <NUM> was to be clamped). Numerous other desirable benefits may also be achieved through the use of outer member <NUM>.

Sheath <NUM> may pass proximally through outer member <NUM> and extend proximally back within handle <NUM>. Intermediate tube <NUM> and inner member <NUM> both also extend back within handle <NUM> and are disposed within sheath <NUM>. The proximal end of sheath <NUM> may be attached to a gear rack assembly <NUM> with a fastener or clip <NUM> as illustrated in <FIG>. Thus, it can be appreciated that proximal movement of gear rack assembly <NUM> may result in analogous proximal movement of deployment sheath <NUM>. Gear rack assembly <NUM> may include a plurality of teeth or gears <NUM>. In practice, teeth <NUM> may be configured to engage with corresponding teeth or gears (not shown) on thumbwheel <NUM>. Consequently, rotation of thumbwheel <NUM>, via gearing thereof with gears <NUM>, can be utilized to proximally retract gear rack assembly <NUM> and, thus, sheath <NUM>. Other structural arrangements may be utilized to accomplish proximal retraction of gear rack assembly <NUM> through the actuation of thumbwheel <NUM> or any other suitable actuation member.

Gear rack assembly <NUM> may also include a flared proximal end <NUM>. When properly assembly, the main body of gear rack assembly <NUM> may be disposed within handle <NUM> and proximal end <NUM> may be disposed along the exterior of handle <NUM>. Gear rack assembly <NUM> may have a slot or groove <NUM> formed therein (not shown in <FIG>, can be seen in <FIG>). Groove <NUM> may extend the length of gear rack assembly <NUM>, including extending along proximal end <NUM>. Because proximal end <NUM> may be generally located near the proximal end of inner member <NUM>, the flared shape of proximal end <NUM> and the orientation of groove <NUM> may allow proximal end <NUM> to function as a guidewire introducer or funnel that may assist a clinician in placing, holding, removing, and/or exchanging a guidewire extending through inner member <NUM>.

In order to properly deploy stent <NUM>, the various components of system <NUM> may need to work in concert so that relative motion of sheath <NUM> can be accomplished relative to inner member <NUM>. In addition, to improve the accuracy of deployment, intermediate tube <NUM> may need to be configured so as to provide the desired longitudinal support necessary to limit proximal movement of stent <NUM>. In at least some embodiments, the proper configuration of these structures may be maintained, at least in part, through the use of a clip member <NUM> as illustrated in <FIG>.

In general, clip member <NUM> is disposed within handle <NUM> and is configured to be secured along the interior of handle <NUM>. Accordingly, clip member <NUM> allows the longitudinal position of one or more portions of system <NUM> to be fixed relative to handle <NUM>. In order to secure clip member <NUM> to handle <NUM>, clip member <NUM> may include one or more fasteners or legs 62a/62b. For example, handle <NUM> may have one or more slots, grooves, openings, or the like that are configured to seat legs 62a/62b such that the relative position of clip member <NUM> relative to handle <NUM> is fixed. In some embodiments, clip member <NUM> may be configured to "snap in" to handle <NUM>. This may desirably simplify manufacturing.

The orientation of clip member <NUM> may be such that it is positioned near one or more structures of system <NUM>. In at least some embodiments, clip member <NUM> may be configured so that at least a portion thereof is positioned within a groove <NUM> (not shown in <FIG>, can be seen in <FIG>) of gear rack assembly <NUM>. This may desirably place clip member <NUM> near inner member <NUM> and intermediate tube <NUM> (which may also extend through groove <NUM>) such that clip member <NUM> can be associated therewith.

Inner member <NUM> may be coupled with clip member <NUM> such that the longitudinal position of inner member <NUM> can be fixed relative to handle <NUM>. For example, clip member <NUM> may include one or more tubular sections, for example a tubular section <NUM>, through which inner member <NUM> may extend. In some embodiments, a sleeve or cuff <NUM> may be disposed about inner member <NUM> at a position proximal of the proximal end of clip member <NUM>. Sleeve <NUM> may substantially prevent any unwanted distal movement of inner member <NUM> via interference with clip member <NUM>.

When stent <NUM> is deployed, a clinician may actuate the actuation thumbwheel <NUM>. Because of the association of thumbwheel <NUM> with gear rack assembly <NUM>, relative rotation of thumbwheel <NUM> causes proximal movement of deployment sheath <NUM>. As deployment sheath <NUM> proximally retracts, stent <NUM> is "uncovered" and (if stent <NUM> is a self-expanding stent) can expand within the body lumen.

In typical stent delivery systems, the relative position of the inner member or structure (e.g., the structure about which the stent is disposed or is loaded on) remains fixed relative to the deployment sheath during stent deployment. In these systems, the inner member is removed from the body lumen by proximally retracting it after the stent is fully deployed. In other words, the deployment process in typical systems generally includes: (<NUM>) proximally retracting the deployment sheath to fully deploy the stent and then (<NUM>) proximally retracting the inner member and/or other components of the system by pulling the inner member proximally through the interior of the deployed stent and, ultimately, out from the body.

Because the inner member of typical stent delivery systems may be designed to include an atraumatic tip, the proximal retracting of the inner member through the interior of the stent also includes proximally retracting the tip through the interior of the stent. Such tips may have an outer profile that approximates the outer diameter of the deployment sheath. In other words, the outer profile of the tip may be relatively "enlarged" as compared to the inner member. Because of the relatively large profile of the tip, there may be a possibility that the tip could engage the stent when being proximally retracted. This could displace the position of the stent, disrupt the structure of the stent, or have any number of undesirable effects.

Stent delivery system <NUM> is designed to help reduce the possibility that tip <NUM> could "catch" on stent <NUM>. For example, system <NUM> is designed to proximally retract inner member <NUM> along with deployment sheath <NUM>. This, desirably, brings tip <NUM> proximally during stent <NUM> deployment and obviates the need for the clinician to pull tip <NUM> back through the full length of stent <NUM> after deployment. In use, a clinician may actuate thumbwheel <NUM> to begin proximally retracting deployment sheath <NUM>. After sheath <NUM> is retracted a relatively short distance, a structural feature of system <NUM> may interact with inner member <NUM> so that inner member <NUM> begins to also retract upon further retraction of deployment sheath <NUM>.

According to the invention, the structural feature of system that may result in proximal movement of inner member <NUM> includes a feature of gear rack assembly <NUM> (which is already associated with proximal movement of deployment sheath <NUM>). For example, gear rack assembly <NUM> may include a loop or catch <NUM> as shown in <FIG>. Loop <NUM> may be positioned a relatively short distance proximally of clip member <NUM>. Inner member <NUM> may extend through loop <NUM>. The short distance between loop <NUM> and clip member <NUM> may allow deployment sheath <NUM> to begin proximally retracting to uncover stent <NUM> and, if stent <NUM> is a self-expanding stent, for stent <NUM> to begin expanding. However, further retraction of deployment sheath <NUM> will ultimately lead to loop <NUM> engaging sleeve <NUM> on inner member <NUM>. Accordingly, any further proximal retraction of deployment sheath <NUM> will result in analogous proximal retraction of inner member <NUM> (and, thus, tip <NUM>). During the deployment, the relative position of intermediate tube <NUM> remains substantially stationary. For example, intermediate tube <NUM> (which is shown spaced from clip member <NUM> in <FIG> but in practice will abut clip member <NUM>) may be positioned so that it abuts clip member <NUM>. Because clip member <NUM> is fixed to handle <NUM>, intermediate tube <NUM> remains substantially fixed and, thus, prevents any unwanted proximal movement of stent <NUM> during deployment.

<FIG> schematically illustrate the deployment of stent <NUM> with system <NUM>. For example, <FIG> illustrates the relative position of the various structures of system <NUM> prior to deployment. With actuation of thumbwheel <NUM>, deployment sheath <NUM> beings to proximally retract (via gear rack assembly <NUM>) to uncover stent <NUM> as illustrated in <FIG>. After gear rack assembly <NUM> is proximally retracted a distance sufficient to result in loop <NUM> engaging sleeve <NUM> of inner member <NUM>, further proximal retraction of gear rack assembly <NUM> begins to also proximally retract inner member <NUM> and, thus, tip <NUM> as shown in <FIG>. Proximal retraction may continue until the full length of stent <NUM> is uncovered and, thus, stent <NUM> is deployed as shown in <FIG>. Because inner member <NUM> is proximally retracted along with deployment sheath <NUM>, tip <NUM> may be positioned near the proximal end of the stent <NUM> at the completion of deployment. This may include positioning proximal ridge <NUM> of tip <NUM> (which may be a possible "catch point" of tip <NUM>) at or near the proximal end of stent <NUM>. Because of this, tip <NUM> only needs to travel a relatively short distance in order to clear stent <NUM> as shown in <FIG>.

While the use of loop <NUM> may be one manner in which the structure of system <NUM> can proximally retract inner member <NUM> along with sheath <NUM>, it can be appreciated that a variety of other structural relationships may be utilized and are contemplated. For example, <FIG> illustrates a portion of another example gear rack assembly <NUM>, which can be used with system <NUM> as well as other systems disclosed and contemplated herein, that includes a projection <NUM> that can interact with sleeve <NUM>. In this embodiment, projection <NUM> may project outward from the inner surface of gear rack assembly <NUM> (e.g., along a portion or all of the interior of groove <NUM>). Projection <NUM> may be sufficiently large so that it can interfere with sleeve <NUM> and, thus, catch on sleeve <NUM> so as to proximally retract inner member <NUM>.

<FIG> illustrates a portion of another example gear rack assembly <NUM>, which can be used with system <NUM> as well as other systems disclosed and contemplated herein, that includes a horseshoe shaped clip <NUM> that can interact with sleeve <NUM>. Clip <NUM> is similar to loop <NUM> except that clip <NUM> does not form a full loop of material that surrounds inner member <NUM>. Such a configuration may be desirable for a number of reasons. For example, clip <NUM> may allow assembly of system <NUM> to include snapping inner member <NUM> into clip <NUM> rather than feeding inner member <NUM> through a complete loop structure. Other forms, shapes, and configurations are contemplated for clip <NUM>.

<FIG> illustrates a portion of another example gear rack assembly <NUM>, which can be used with system <NUM> as well as other systems disclosed and contemplated herein, that includes a loop assembly <NUM> that can interact with sleeve <NUM>. Loop assembly <NUM> may include loop 370a and a rod 370b that may be accessible along the exterior of handle <NUM> so that a user can manipulate the position of inner member <NUM> manually. It should be noted that loop 370a may be complete loop (e.g., similar to loop <NUM>) or a partial loop (e.g., similar to clip <NUM>). Other forms and configurations are contemplated for loop assembly <NUM>.

The materials that can be used for the various components of system <NUM> (and/or other systems disclosed herein) may include those commonly associated with medical devices. For simplicity purposes, the following discussion makes reference to shaft <NUM>, deployment sheath <NUM>, and inner member <NUM>. However, this is not intended to limit the invention as the discussion may be applied to other similar members and/or components of members or systems disclosed herein.

Shaft <NUM>, deployment sheath <NUM>, and inner member <NUM>, and/or other components of system <NUM> may be made from a metal, metal alloy, polymer (some examples of which are disclosed below), a metal-polymer composite, combinations thereof, and the like, or any other suitable material. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, <NUM>, and 316LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic and/or super-elastic nitinol; other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® <NUM>, UNS: N06022 such as HASTELLOY® C-<NUM>®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® <NUM>, NICKELVAC® <NUM>, NICORROS® <NUM>, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g., UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like); platinum enriched stainless steel; titanium; combinations thereof; and the like; or any other suitable material.

As alluded to above, within the family of commercially available nickel-titanium or nitinol alloys, is a category designated "linear elastic" or "non-super-elastic" which, although may be similar in chemistry to conventional shape memory and super elastic varieties, may exhibit distinct and useful mechanical properties. Instead, in the linear elastic and/or non-super-elastic nitinol, as recoverable strain increases, the stress continues to increase in a substantially linear, or a somewhat, but not necessarily entirely linear relationship until plastic deformation begins or at least in a relationship that is more linear that the super elastic plateau and/or flag region that may be seen with super elastic nitinol.

Both of these materials can be distinguished from other linear elastic materials such as stainless steel (that can also can be distinguished based on its composition), which may accept only about <NUM>-<NUM>% strain before plastically deforming.

In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy is an alloy that does not show any martensite/austenite phase changes that are detectable by DSC and DMTA analysis over a large temperature range. For example, in some embodiments, there may be no martensite/austenite phase changes detectable by DSC and DMTA analysis in the range of about -<NUM> to about <NUM> in the linear elastic and/or non-super-elastic nickel-titanium alloy. In other words, across a broad temperature range, the linear elastic and/or non-super-elastic nickel-titanium alloy maintains its linear elastic and/or non-super-elastic characteristics and/or properties and has essentially no yield point.

of Kanagawa, Japan. Some examples of nickel titanium alloys are disclosed in <CIT> and <CIT>.

In at least some embodiments, portions or all of shaft <NUM>, deployment sheath <NUM>, and inner member <NUM> may also be doped with, made of, or otherwise include a radiopaque material including those listed herein or other suitable radiopaque materials.

In some embodiments, a degree of MRI compatibility is imparted into system <NUM>. For example, to enhance compatibility with Magnetic Resonance Imaging (MRI) machines, it may be desirable to make shaft <NUM>, deployment sheath <NUM>, and inner member <NUM>, in a manner that would impart a degree of MRI compatibility. For example, shaft <NUM>, deployment sheath <NUM>, and inner member <NUM>, or portions thereof, may be made of a material that does not substantially distort the image and create substantial artifacts (artifacts are gaps in the image). Certain ferromagnetic materials, for example, may not be suitable because they may create artifacts in an MRI image. Shaft <NUM>, deployment sheath <NUM>, and inner member <NUM>, or portions thereof, may also be made from a material that the MRI machine can image. Some materials that exhibit these characteristics include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nitinol, and the like, and others.

Some examples of suitable polymers that may be used to form shaft <NUM>, deployment sheath <NUM>, and inner member <NUM>, and/or other components of system <NUM> may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example, DELRIN® available from DuPont), polyether block ester, polyurethane (for example, Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene/poly(alkylene ether) phthalate and/or other polyester elastomers such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example available under the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly paraphenylene terephthalamide (for example, KEVLAR®), polysulfone, nylon, nylon-<NUM> (such as GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS 50A), polycarbonates, ionomers, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. In some embodiments the sheath can be blended with a liquid crystal polymer (LCP). For example, the mixture can contain up to about <NUM>% LCP.

In some embodiments, the exterior surface of the system <NUM> may include a coating, for example a lubricious, a hydrophilic, a protective, or other type of coating. Hydrophobic coatings such as fluoropolymers provide a dry lubricity which improves device handling and exchanges. Lubricious coatings improve steerability and improve lesion crossing capability. Suitable lubricious polymers may include silicone and the like, polymers such as high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylene oxides, polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics, algins, saccharides, caprolactones, and the like, and mixtures and combinations thereof. Hydrophilic polymers may be blended among themselves or with formulated amounts of water insoluble compounds (including some polymers) to yield coatings with suitable lubricity, bonding, and solubility. Some other examples of such coatings and materials and methods used to create such coatings can be found in <CIT> and <CIT>.

Claim 1:
A stent delivery system (<NUM>), comprising:
an inner member (<NUM>) having an enlarged proximal end and an atraumatic distal tip (<NUM>);
a stent (<NUM>) disposed about the inner member (<NUM>);
a deployment sheath (<NUM>) disposed about the inner member (<NUM>) and the stent (<NUM>);
a gear rack assembly (<NUM>) coupled to the deployment sheath (<NUM>);
a handle (<NUM>) coupled to the inner member (<NUM>) and to the deployment sheath (<NUM>);
wherein the handle (<NUM>) includes a thumbwheel (<NUM>) that is coupled to the gear rack assembly (<NUM>) so that rotation of the thumbwheel (<NUM>) proximally retracts the gear rack assembly (<NUM>) and the deployment sheath (<NUM>); characterized in that the stent delivery system further comprises an intermediate tube (<NUM>) disposed between the inner member (<NUM>) and the deployment sheath (<NUM>), and
an engagement mechanism coupled to the gear rack assembly (<NUM>), the engagement mechanism being configured to catch on the enlarged proximal end of the inner member (<NUM>), after the deployment sheath (<NUM>) is proximally retracted a distance, and proximally retract the inner member (<NUM>).