Rapid exchange stent delivery system

Stent delivery systems and methods for making and using stent delivery systems are disclosed. An example stent delivery system may include a guide member having a proximal portion and a distal portion. A stent may be disposed about the distal portion of the guide member. The stent may have a wall having an opening formed therein. A pusher member may be disposed about the guide member and positioned proximal of the stent. A holding filament may be disposed at the opening and may extend to the proximal portion of the guide member. The holding filament may be configured to releasably secure the position of the stent relative to the pusher member. The holding filament may be releasable from the stent independently of movement of the guide member.

FIELD OF THE INVENTION

The present invention pertains to medical devices and methods for manufacturing medical devices. More particularly, the present invention pertains to medical devices for delivering stents to the biliary tract and/or the pancreatic tract.

BACKGROUND

BRIEF SUMMARY

The invention provides design, material, manufacturing method, and use alternatives for medical devices or components thereof. An example medical device may be a stent delivery system that includes a guide member having a proximal portion and a distal portion. A stent may be disposed about the distal portion of the guide member. The stent may have a wall having an opening formed therein. A pusher member may be disposed about the guide member and positioned proximal of the stent. A holding filament may be disposed at the opening and may extend to the proximal portion of the guide member. The holding filament may be configured to releasably secure the position of the stent relative to the pusher member. In addition, the holding filament may be releasable from the stent independently of movement of the guide member.

An example method for delivering a biliary or pancreatic stent may include providing a stent delivery system. The stent delivery system may include a guide member having a proximal portion and a distal portion. A stent may be disposed about the distal portion of the guide member. The stent may have a wall having an opening formed therein. A pusher member may be disposed about the guide member and positioned proximal of the stent. A filament may be disposed at the opening and may extend to the proximal portion of the guide member. The filament may be configured to releasably secure the position of the stent relative to the pusher member. In addition, the filament may be releasable from the stent independently of movement of the guide member. The method may also include advancing the stent delivery system along a body lumen to a position adjacent to an area of interest and releasing the filament from the stent.

An example delivery system for delivering a biliary or pancreatic stent may include a guide tube. A drainage stent may be disposed about the guide tube. The drainage stent may be tubular and may have a tube wall with an opening formed therein. A push catheter may be disposed about a portion of the guide member proximal of the drainage stent. The delivery system may also include filament for securing the position of the drainage stent relative to the push catheter. The stent may be configured to be in either a first configuration where the stent is releasably secured relative to the push catheter with the filament or a second configuration where the filament is released from the stent. The guide tube may extend through the stent in both the first and second configurations.

The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures and Detailed Description which follow more particularly exemplify these embodiments.

DETAILED DESCRIPTION

A wide variety of biliary, endoscopic, and/or endosurgical procedures have been developed for making medical treatments, diagnoses, and images of areas along the biliary tract and/or the pancreatic tract. For the purposes of this disclosure, the “biliary tract” and/or the “pancreatic tract” are understood to include various components of the digestive system and include, for example, the various ducts of the biliary tree between the liver and the duodenum as well as the various ducts between the pancreas and the duodenum. Numerous endoscopic and/or endosurgical devices have been developed for making medical treatments, diagnoses, and images of areas along the biliary and pancreatic tracts. Some of these device and/or procedures include biliary catheters, biliary guidewires, biliary stent delivery systems, and the like. In general, these devices are guided to the biliary and/or pancreatic tract by an endoscope (and/or a duodenoscope) that is disposed in the duodenum. Once positioned, various interventions can be performed depending on the needs of the patient and the type of device utilized. Other locations and/or uses are also contemplated for the systems disclosed herein including, for example, urinary tract interventions and/or urological interventions, gynecological interventions, etc.

When delivering a stent such as a drainage stent to the appropriate position within the anatomy, it may be desirable to hold or secure the position of the stent relative to a push catheter, which may be part of the stent delivery system. This allows the clinician to position and deploy the stent accurately at the intended location. One way that the stent may be secured to the push catheter may be with the use of a suture. Conventionally when a suture is utilized to secure a stent to a push catheter, the suture is formed into a loop that is wrapped around the guide catheter (which may extend through the lumen of the push catheter). The suture then extends through one of the barbed openings or flaps formed in the stent and it may be pulled snugly and attached or tied to the end of the push catheter, for example at a hole or opening formed at the distal end of the push catheter. As long as the position of the guide catheter is held stationary relative to the push catheter, this arrangement holds the position of the stent and effectively secures the stent to the push catheter. To release the stent, the guide catheter can be proximally retracted to a point where it exits and is disposed proximally of the loop formed in the suture. When no longer wrapped around the guide catheter, the loop or looped end of the suture is free to simply exit the opening at the barbed flap of the stent such that the stent is released from the push catheter.

While effective, the above-described conventional use of a suture to secure the stent relative to the push catheter is dependent on the manipulation of the guide catheter in order to deploy the stent. Furthermore, should the clinician desire to reposition the stent after deployment (e.g., due to improper or undesirable placement), additional manipulation steps may be required including further manipulation of the guide catheter.

Disclosed herein are a number of delivery systems for delivery a stent (e.g., a drainage stent) to an appropriate position within the anatomy. The delivery systems may use a holding filament or structure such as a suture to secure the position of the stent relative to a push member or catheter. Deployment or release of the stent from the push catheter, however, can be accomplished independently of movement of the guide catheter. Furthermore, the delivery systems disclosed herein may also allow the clinician to “resecure” the sent to the push catheter or otherwise allow for the clinician to reposition the stent, again independently of movement of the guide catheter. Some additional details regarding these and other features of a number of different example stent delivery systems are provided below.

Referring now toFIGS. 1 and 2, there is shown an example medical device, illustrated as a delivery system10for delivering, for example, a stent20such as a drainage stent to a suitable target location such as, for example, a target along the biliary and/or pancreatic tree. The system10may also be used at any other suitable location. The stent20may be used to bypass or drain an obstructed lumen, for example along the biliary and/or pancreatic tree, and can be configured for long-term positioning within the body. It should be understood that the terms “drainage stent”, “drainage catheter” and “stent” can be used interchangeably with reference to the devices and systems disclosed herein.

The delivery system10may be designed for use with a conventional guidewire2and may include a guide catheter12, a push catheter14, and a handle assembly16. The guidewire2may extend into a lumen22of the guide catheter12, through a distal guidewire port24, and out a proximal guidewire port26formed in a sidewall of the push catheter14, providing the delivery system10with single-operator-exchange (SOE) capabilities. Other embodiments are also contemplated, however, where the delivery system10is an over-the-wire (OTW) system.

The guide catheter12may be slidably disposed within the lumen28of the push catheter14and may extend distally from the distal end of the push catheter14. The stent20may be positioned on a distal portion of the guide catheter12, which may be located distal of the push catheter14, and the stent20may abut the distal end30of the push catheter14. The system10may also include a holding filament or suture44for releasably connecting the push catheter14to the stent20. Some additional details regarding the holding filament44and/or the connection of the stent20with the push catheter14(and/or other structures of the system10) are provided below. When the stent20has been properly placed, the stent20may be disconnected from the push catheter14such that the stent20remains in the anatomy or body lumen when the push catheter14is withdrawn.

The proximal end32of the push catheter14may be attached to the handle assembly16. For example, the proximal end32may include a female luer lock connector34threadably coupled to a threaded male connector36of the handle assembly16. It may be understood, however, that the push catheter14may be attached to the handle assembly16and extend distally therefrom by other means, such as adhesive bonding, welding, friction fit, interlocking fit, or other suitable means.

The guide catheter12may include a distal tubular portion38and a proximal elongate wire40, such as a pull wire, coupled to the distal tubular portion38. In some instances, the elongate wire40may be a wire, filament, thread, portion of a catheter wall, fabric, web, or similar elongate structure. The elongate wire40may be coupled to the distal tubular portion38at a rotatable connection that may allow rotatable movement between the tubular portion38and the elongate wire40of the guide catheter12. The elongate wire40may extend through the lumen28of the push catheter14to the handle assembly16. In some embodiments, the elongate wire40may extend through the handle assembly16to a location proximal of the handle assembly16. The proximal end of elongate wire40may terminate at a knob42which may be grasped by an operator to manipulate the guide catheter12.

As shown inFIG. 2, the elongate wire40may share the lumen28of the push catheter14with the guidewire2along a portion of the length of the elongate wire40. Thus, a portion of the elongate wire40may extend proximally from the tubular portion38along the side of the guidewire2through the lumen28of the push catheter14up to a location where the guidewire2exits the proximal guidewire port26of the push catheter14.

As indicated above, the holding filament44may secure the stent20to the push member. In at least some embodiments, the holding filament44is a suture. However, this is not intended to be limiting as the holding filament44may take the form of any suitable structure such as a wire, cord, braid, coil, or the like. Indeed, the holding filament44may be a mono-filament structure (e.g., made from a singular filament) or multi-filament structure (e.g., made from a plurality of filaments that may or may not be the same). The holding filament may be made from any suitable material including polymers, natural materials, metals, catgut, cotton, and the like, combinations thereof, or any other suitable material including those materials disclosed herein. In some embodiments, more than one holding filaments44may be utilized. It should be understood that the terms “holding filament” and “suture” can be used interchangeably with reference to the devices and systems disclosed herein.

The stent20may include one or more anchors46that are generally disposed near an opening50in the stent20. Anchors46, for example, may project radially outward from the stent20and help to secure or “anchor” the position of the stent20within the anatomy when deployed. In at least some embodiments, the anchors46are defined by a skived cut in the stent20and take the form of a barb or barb-like flap. Other configurations are contemplated.

In at least some embodiments, the suture44may wrap around the anchor46. Such a configuration may also be described as the suture44being disposed in the opening50, at the opening50, or adjacent the opening50of the stent20. The suture44, rather than being tied to the push catheter14, may extend proximally along the push catheter14to a position adjacent the handle assembly16. For example, the suture44may extend to a control or actuation member, shown generally at reference number48. In other embodiments, the ends of the suture44may extend back toward the handle assembly16and be accessible to the user such that the control48is optional or may be omitted. In general, the suture44may be free of attachment or securement to the push catheter14.

The control48, which may or may not be secured to the handle assembly16, may allow the clinician to manipulate and/or alter the attachment of the stent20to the push catheter14. For example, the control48may allow the user to release one end of the suture44(e.g., when the suture is formed as a loop so that two ends extend to the control48) and pull the other end so that the suture44is proximally retracted until the suture44is no longer wrapped around the anchor46. This essentially “frees” the stent20from the pusher member14. If the control48is not being utilized, the same thing can be accomplished by the user releasing one of the ends of the suture44and proximally retracting the other end until the suture44is no longer wrapped around the anchor46. In other embodiments, the user may actuate the control48or otherwise pull on the suture such that sufficient force is generated to sever the suture44(e.g., break, cut, or otherwise become dissociated with the anchor46) and effect release of the stent20. For example, the suture44may be predisposed to break at a predetermined force by altering the suture by thinning (e.g., in diameter) a portion thereof, by omitting structure that might otherwise strengthen or support the suture (e.g., braids, etc.), notching, making the suture44brittle (e.g., brittle at a pre-determined location), etc. Other configurations are contemplated for releasing the stent20from the pusher member14.

In addition to being configured to release the stent20from the pusher member14and/or to deploy the stent20, the holding filament/suture44may also be used to reposition the stent20. For example, the suture44may be partially actuated. For the purposes of this disclosure, partially actuating the suture44may be understood to be “loosening” or otherwise be manipulating the suture44so as to create enough slack therein that the pusher member14can be moved a relatively short distance away from to the stent20. This may allow the stent20to at least partially deploy or be placed within the anatomy. The user may then observe or visualize the position of the stent20. If the user decides that the position of the stent20needs to be altered, the slack in the suture20can be removed (e.g., the suture20can be “tightened”) so that the stent20once again become secured to the pusher member14and the stent20can be repositioned (e.g., urged distally and/or proximally, as desired). Once the user is satisfied with the position of the stent20, the suture44can be “fully actuated” (e.g., in one of the manners disclosed herein or any other suitable manner) so that the stent20is deployed and the delivery device10can be removed from the anatomy.

FIG. 3illustrates another example arrangement for the suture44that may be utilized with the delivery device10. In this embodiment, the suture44be wrapped around the anchor46and be tied into a knot52. According to this embodiment, only a singular “end” of the suture44(rather than two opposite ends) may extend to the control48or otherwise be accessible to the user. To release the stent20, sufficient force may be exerted onto suture44so as to sever the suture44(e.g., at or adjacent the knot52) and release the stent20. Alternatively, the knot52may be a slip-type knot so that the knot52can be untied by pulling on the end of the suture44. In still other embodiments, a secondary suture (not shown) may be coupled to the knot52and, for example, extend proximally to the handle assembly16. The secondary suture may be actuated to release the knot52. Numerous other configurations are contemplated.

FIGS. 4-5illustrates additional example arrangements for the suture44that may be utilized with the delivery device10. In the embodiment illustrated inFIG. 4, the suture44again wraps around the anchor46. However, instead of being disposed along the exterior of the push catheter14, for example as shown inFIGS. 1-3, the suture44extends along the interior of the push catheter14, for example through the lumen28of the push catheter14or otherwise between the push catheter14and the guide catheter12. In the embodiment illustrated inFIG. 5, the suture44may extend through the opening50in the stent22and tied into a knot52, and the singular end may extend proximally through the lumen28of the push catheter14or otherwise between the push catheter14and the guide catheter12.

Other embodiments are also contemplated where the suture44may extend through the opening50of the stent20. According to these embodiments, one end of the suture44may extend along the exterior of the push catheter14. The other end of the suture44may extend along the interior of the push catheter14or the other end of the suture44may follow the interior of the stent20, extend between the proximal end of the stent20and the distal end30of the push catheter14, and then extend along the exterior of the push catheter14. Alternatively, one end of the suture44may extend along the interior of the push catheter14and the other end of the suture44may either extend along the interior of the push catheter14or it may follow the exterior of the stent20, extend between the proximal end of the stent20and the distal end30of the push catheter14, and then extend along the interior of the push catheter14.

FIG. 6-7illustrate additional example arrangements for the suture44that may be utilized with the delivery device10. In the embodiment illustrated inFIG. 6, the stent120has an opening151formed therein. The opening151is different from the opening150formed at the anchor146. For example, the opening151may be positioned adjacent to the anchor146, proximal of the anchor146, or at any other suitable location. Indeed, in some embodiment, the stent120may not have an opening at the anchor146. This may be true in this or any other embodiment disclosed herein. The suture44may be looped through the opening151and then the suture44may along the exterior of the push catheter14, for example, to the control48. In the embodiment illustrated inFIG. 7, the suture44may be looped through the opening151and tied into a knot52. The end of the suture44may extend along the exterior of the push catheter14to the control48.

FIGS. 8-9illustrates additional example arrangements for the suture44that may be utilized with the delivery device10. In the embodiment illustrated inFIG. 8, the suture44is again looped through the opening151in the stent120and then extends along the interior of the push catheter14, for example through the lumen28of the push catheter14or otherwise between the push catheter14and the guide catheter12. In the embodiment illustrated inFIG. 9, the suture44is again looped through the opening151in the stent120and tied into a knot52and the singular end extends along the interior of the push catheter14, for example through the lumen28of the push catheter14or otherwise between the push catheter14and the guide catheter12.

FIGS. 10-12illustrates alternative example push catheters that may be utilized with the delivery system10. In general, these push catheters have one or more openings or lumens formed in the wall of the push catheter. The suture44may pass through the lumen(s) to a position adjacent the handle assembly16so that the suture44may be associated with the control48or otherwise accessible to the user. The use of such push catheters having one or more lumens in the wall may be desirable for a number of reasons. For example, the use of push catheters having one or more lumens in the wall may allow the suture44to extend proximally back toward the handle assembly16without being either exposed to either the exterior of the push catheter14or the interior the push catheter14(e.g., between the push catheter14and the guide catheter12) where the suture44could get caught on, break, or otherwise disrupt other structures of the delivery system10and/or interrupt proper delivery of the stent (e.g., the stent20/120).

FIG. 10illustrates the push catheter214having a single opening or lumen254formed in the wall256thereof. In embodiments such as those shown inFIGS. 1-2,4,6, and8, where the two opposite ends of the suture44may extend back toward the handle assembly16, the single lumen254allows both ends of the suture44(which are shown inFIG. 10and bear reference numbers44a/44b) to extend proximally through a singular channel. In embodiments such as those shown inFIGS. 3,5,7, and9, where the suture44is tied into a knot52and a singular “end” extends back toward the handle assembly16, the single lumen254may allow this singular end of the suture to extend proximally toward the handle assembly as shown inFIG. 11. In the embodiment shown inFIG. 12, a pair of lumens354a/354bare formed in the wall of the push catheter314. According to this embodiment, each of the ends44a/44bof the suture44can extend through its own lumen354a/354b.

FIGS. 13-14illustrate additional contemplated push catheters. For example,FIG. 13illustrates the push catheter414having a groove458. In this embodiment, the groove458is formed in the outer surface of the push catheter414. The groove458may act as a guide for the suture or holding filament. The groove458may extend along one or more discrete portions of the length of the push catheter414or along essentially the full length thereof. Similarly,FIG. 14illustrates the push catheter514with a groove558formed along an inner surface. Just like groove458, groove558may extend along one or more discrete portions of the length of the push catheter514or along essentially the full length thereof. Either or both of the grooves458/558may be utilized in any of the embodiments disclosed herein.

FIGS. 15-19illustrate additional example arrangements for a holding filament that may be utilized with a stent delivery system including any of those disclosed herein. For example, inFIG. 15the holding filament644includes a first portion660, which may take the form of a looped wire, and a second portion661, which may also take the form of a looped wire. The portions660/661may loop or otherwise intersect with one another at an intersection662and they may extent around the anchor46. Similarly, inFIG. 16the holding filament744includes a first portion760taking the form of a loop and a second portion761taking the form of a single filament. The portions760/761may be joined at a knot752and they may extend around the anchor46. Finally, as shown inFIG. 17the holding filament844may include a first portion860taking the form of a single filament tied with a knot852ato form a loop and a second portion861also taking the form of a single filament tied with a knot852bto form a loop. The loops may join together at an intersection862and the portions860/861may extend around the anchor46. Any of the holding filaments and/or arrangements of holding filaments may be utilized with any of the systems disclosed herein.

FIGS. 18-19illustrate additional holding filament arrangements that may also be used with any of the systems disclosed herein. For example, one example holding filament944, as shown inFIG. 18, may include a first portion944aand a second portion944bjoined together with a bond952. In some embodiments, the bond952may be an adhesive. Other bonds may also be utilized. Similarly,FIG. 19illustrates another example holding filament1044that includes a first looped portion1044aand a second looped portion1044bjoined together with a bond1052. The bond1052, just like the bond952, may include adhesive or any other suitable bonding material.

The materials that can be used for the various components of the delivery system10may include those commonly associated with medical devices. For simplicity purposes, the following discussion makes reference to the push catheter14. However, this is not intended to limit the devices and methods described herein, as the discussion may be applied to any of the other structures and/or components of the delivery devices disclosed herein.

In some embodiments, a degree of Magnetic Resonance Imaging (MRI) compatibility is imparted into the delivery device10. For example, to enhance compatibility with MRI machines, it may be desirable to make the push catheter14, or other portions of the delivery device10, in a manner that would impart a degree of MRI compatibility. For example, the push catheter14, or portions thereof, may be made of a material that does not substantially distort the image and create substantial artifacts (i.e., gaps in the image). Certain ferromagnetic materials, for example, may not be suitable because they may create artifacts in an MRI image. The push catheter14, 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.

In some embodiments, the exterior surface of the delivery device10may be sandblasted, beadblasted, sodium bicarbonate-blasted, electropolished, etc. In these as well as in some other embodiments, a coating, for example a lubricious, a hydrophilic, a protective, or other type of coating may be applied over portions or all of the delivery device10. Hydrophobic coatings such as fluoropolymers provide a dry lubricity which improves guidewire handling and device exchanges. Lubricious coatings improve steerability and improve lesion crossing capability. Suitable lubricious polymers are well known in the art and may include silicone and the like, hydrophilic 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 U.S. Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein by reference.

The coating and/or sheath may be formed, for example, by coating, extrusion, co-extrusion, interrupted layer co-extrusion (ILC), or fusing several segments end-to-end. The layer may have a uniform stiffness or a gradual reduction in stiffness from the proximal end to the distal end thereof. The gradual reduction in stiffness may be continuous as by ILC or may be stepped as by fusing together separate extruded tubular segments. The outer layer may be impregnated with a radiopaque filler material to facilitate radiographic visualization. Those skilled in the art will recognize that these materials can vary widely without deviating from the scope of the present invention.

The arrangement of the various structures of the delivery system10may vary. In some embodiments, the system10may include any of the structures or utilize any of the arrangements of structures that are disclosed in U.S. Pat. Nos. 5,152,749; 5,334,185; 5,921,952; 6,248,100; 6,264,624; and 6,562,024, the entire disclosures of which are herein incorporated by reference.

It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed.