US20020120323A1 - Implant delivery system with interlock - Google Patents

Abstract

An implant delivery system is disclosed. The delivery system includes an elongated member having an implant mounting location. A self-expandable implant is mounted at the implant mounting location. The implant is held in a compressed orientation by a retractable sheath. An interlock structure prevents the implant from deploying prematurely as the sheath is retracted.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation-in-part of U.S. patent application Ser. No. 09/795,047 entitled Implant Delivery System with Interlock, that was filed on Feb. 26, 2001.[0001]
BACKGROUND OF THE INVENTION
• 1. Field of Invention[0002]
• This invention pertains to a system for delivering an implant to a site in a body lumen. More particularly, this invention pertains to a delivery system for a self-expandable implant such as a stent.[0003]
• 2. Description of the Prior Art[0004]
• Stents are widely used for supporting a lumen structure in a patient's body. For example, stents may be used to maintain patency of a coronary artery, other blood vessels or other body lumen.[0005]
• Stents are commonly metal, tubular structures. Stents are passed through a body lumen in a collapsed state. At the point of an obstruction or other deployment site in the body lumen, the stent is expanded to an expanded diameter to support the lumen at the deployment site.[0006]
• In certain designs, stents are open-celled tubes that are expanded by inflatable balloons at the deployment site. This type of stent is often referred to as a “balloon expandable” stent. Other stents are so-called “self-expanding” stents. Self-expanding stents do not use balloons to cause the expansion of the stent. An example of a self-expanding stent is a tube (e.g., a coil tube or an open-celled tube) made of an elastically deformable material (e.g., a superelastic material such a nitinol). This type of stent is secured to a stent delivery device under tension in a collapsed state. At the deployment site, the stent is released so that internal tension within the stent causes the stent to self-expand to its enlarged diameter. Other self-expanding stents are made of so-called shape-memory metals. Such shape-memory stents experience a phase change at the elevated temperature of the human body. The phase change results in expansion from a collapsed state to an enlarged state.[0007]
• A delivery technique for elastically deformable stents is to mount the collapsed stent on a distal end of a stent delivery system. Such a system would include an outer tubular member and an inner tubular member. The inner and outer tubular members are axially slideable relative to one another. The stent (in the collapsed state) is mounted surrounding the inner tubular member at its distal end. The outer tubular member (also called the outer sheath) surrounds the stent at the distal end.[0008]
• Prior to advancing the stent delivery system through the body lumen, a guide wire is first passed through the body lumen to the deployment site. The inner tube of the delivery system is hollow throughout its length such that it can be advanced over the guide wire to the deployment site.[0009]
• The combined structure (i.e., stent mounted on stent delivery system) is passed through the patient's lumen until the distal end of the delivery system arrives at the deployment site within the body lumen. The deployment system may include radiopaque markers to permit a physician to visualize positioning of the stent under fluoroscopy prior to deployment.[0010]
• At the deployment site, the outer sheath is retracted to expose the stent. The exposed stent is now free to self-expand within the body lumen. Following expansion of the stent, the inner tube is free to pass through the stent such that the delivery system can be removed through the body lumen leaving the stent in place at the deployment site.[0011]
• In prior art devices, the stent may prematurely deploy as the outer tube is retracted. Namely, with the outer tube partially retracted, the exposed portion of the stent may expand resulting in the remainder of the stent being squeezed out of the outer tube. This can result in the stent being propelled distally beyond a desired deployment site. Also, once the stent is partially unsheathed, it is sometimes determined that the stent placement needs to be adjusted. With existing systems, this is difficult since the stent has a tendency to force itself out of the sheath thereby making adjustments difficult. What is needed is a system that retains the stent on the catheter even when a majority of the stent has been exposed by retraction of the sheath. What is also needed is a system that allows a stent to be re-sheathed even after a majority of the stent has been exposed by retraction of the sheath.[0012]
SUMMARY OF THE INVENTION
• One embodiment of the present invention relates to an implant delivery system that provides enhanced placement control of the implant.[0013]
• A variety of advantages of the invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.[0014]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a side elevation view of a stent delivery system according to the present invention;[0015]
• FIG. 2A is an enlarged cross-sectional view of detail A of FIG. 1 with the stent in a compressed orientation;[0016]
• FIG. 2B is an enlarged cross-sectional view of detail A of FIG. 1 with the stent in a deployed (i.e., expanded) orientation;[0017]
• FIG. 3 is an enlarged cross-sectional view of detail B of FIG. 1;[0018]
• FIG. 4 is an enlarged cross-sectional view of detail C;[0019]
• FIG. 5 is a cross-sectional view of the inner and outer tubular members of the stent delivery system of FIG. 1 taken along section line[0020]5-5 of FIG. 3;
• FIG. 6A is a plan view of a first stent having an interlock structure that interlocks with an interlock structure of a mating collar, the stent and the collar are shown cut longitudinally and laid flat with an axial separation between the stent proximal end and the mating collar;[0021]
• FIG. 6B is the view of FIG. 6A with the stent proximal end and mating collar shown interlocked;[0022]
• FIG. 6C is an end view of the stent of FIGS. 6A and 6B in its tubular configuration;[0023]
• FIG. 7 is a laid flat, plan view of a second stent having an interlock structure that interlocks with an interlock structure of a mating collar, the collar includes rotational positioning indicators;[0024]
• FIG. 8 is a laid flat, plan view of a third stent having an interlock structure that interlocks with an interlock structure of a mating collar, the collar includes rotational positioning notches;[0025]
• FIG. 9 is a laid flat, plan view of a fourth stent having an interlock structure that interlocks with an interlock structure of a mating collar, the stent and the collar include a rotational alignment key and keyway;[0026]
• FIG. 10 is a laid flat, plan view of a fifth stent having an interlock structure that interlocks with an interlock structure of a mating collar;[0027]
• FIG. 11 is a laid flat, plan view of a sixth stent having an interlock structure that interlocks with an interlock structure of a mating collar;[0028]
• FIG. 12 is a laid flat, plan view of a seventh stent having an interlock structure that interlocks with rectangular posts formed on an inner body of a catheter;[0029]
• FIG. 13 is a laid flat, plan view of a eighth stent having an interlock structure that interlocks with an interlock structure of a mating collar;[0030]
• FIG. 14A is a laid flat, plan view of a ninth stent having an interlock structure that interlocks with outwardly projecting line-like projections formed on the inner body of a catheter;[0031]
• FIG. 14B shows the stent of FIG. 14A interlocked with the line-like projections;[0032]
• FIG. 15A is a laid flat, plan view of a tenth stent having an interlock structure that interlocks with outwardly projecting posts formed on the inner body of a catheter;[0033]
• FIG. 15B shows the stent of FIG. 15A interlocked with the posts; and[0034]
• FIGS. 16A and 16B show another delivery system that is an embodiment of the present invention.[0035]
DETAILED DESCRIPTION
• With reference now to the various drawing figures in which identical elements are numbered identically throughout, a description of a preferred embodiment of the present invention will now be provided.[0036]
• With initial references to FIGS.[0037]1-4, astent delivery system10 is shown. Thestent delivery system10 is for delivery of astent12 to a deployment site in a body lumen of a patient's body. By way of non-limiting, representative example, thestent12 may be a self-expanding stent having a construction such as that shown in U.S. Pat. No. 6,132,461. In one non-limiting embodiment, the stent can be made of a superelastic metal such as nitinol, or the like. Thestent12 may also be a coil stent or any other self-expanding stent. Thestent12 includes aproximal end12aand adistal end12b. Another representative stent is shown in U.S. patent application Ser. No. 09/765,725, filed Jan. 18, 2001 and entitled STENT, which is hereby incorporated by reference.
• The[0038]stent12 is carried on thestent delivery system10 in a collapsed (or reduced diameter) state as shown in FIG. 2A. Upon release of thestent12 from the stent delivery system10 (as will be described), thestent12 expands to an enlarged diameter (see FIG. 2B) to abut against the walls of the patient's lumen in order to support patency of the lumen.
• The[0039]stent delivery system10 includes an inner tubular member14 (i.e., also referred to as an elongated member) and anouter tubular member16. Both of the inner and outertubular members14 and16 extend from proximal ends14a,16atodistal ends14b,16b.
• The outer[0040]tubular member16 is sized to be axially advanced through the patient's body lumen. Thetubular member16 is preferably sufficiently long for thedistal end16bto be placed near the deployment site in the patient's body lumen with theproximal end16aremaining external to the patient's body for manipulation by an operator. By way of example, the outer tubular member16 (also referred to as a sheath) may be a braid-reinforced polyester of tubular construction to resist kinking and to transmit axial forces along the length of thesheath16. The outertubular member16 may be of widely varying construction to permit varying degrees of flexibility of the outertubular member16 along its length.
• As shown in FIG. 3, the[0041]proximal end16aof the outertubular member16 is bonded to amanifold housing20. Themanifold housing20 is threadedly connected to alock housing22. Astrain relief jacket24 is connected to themanifold housing20 and surrounds the outertubular member16 to provide strain relief for the outertubular member16.
• The[0042]inner tubular member14 is preferably formed of nylon but may be constructed of any suitable material. As shown in FIG. 2B, theinner tubular member14 defines a stent attachment location26 (i.e., a stent mounting location). Theinner tubular member14 also includesmarkers27,28 that are attached to an outer surface of the inner tubular member14 (e.g., by techniques such as adhesive, heat fusion, interference fit, fasteners, intermediate members or other techniques). Theattachment location26 is positioned between themarkers27,28. Theradiopaque markers27,28 permit a physician to accurately determine the position of thestent attachment location26 within the patient's lumen under fluoroscopic visualization. As will be described later in the specification, in some embodiments, at least one of themarkers27,28 forms a collar including a geometry that interlocks with thestent12 to prevent axial movement of thestent12 relative to the inner tubular member during transport and deployment of thestent12. Materials for making the radiopaque marker should have a density suitable for visualization through fluoroscopic techniques. Exemplary materials comprise tanalum, platinum, gold, tungsten and alloys of such metals. In some embodiments, the markers can be coated with a radiopaque material or filled with a radiopaque filler.
• A tapered and flexible[0043]distal tip member30 is secured to thedistal end14bof theinner tubular member14. The highly flexibledistal tip member30 permits advancement of thestent deployment system10 through the patient's lumen and minimizes trauma to the walls of the patient's lumen. As shown in FIG. 2B, theinner tubular member14 preferably extends completely through thestent12 when thestent12 is mounted at theattachment location26.
• As best shown in FIGS. 3 and 4, the[0044]inner tube14 passes through both themanifold housing20 and lockhousing22. Astainless steel jacket32 surrounds and is bonded to theinner tubular member14.
• At the inner tube[0045]proximal end14a, aport housing34 is bonded to thestainless steel jacket32. Theport housing34 has a taperedbore36 aligned with aninner lumen38 of thetubular member14. Theinner lumen38 extends completely through theinner tubular member14 so that theentire delivery system10 can be passed over a guide wire (not shown) initially positioned within the patient's lumen. Opposing surfaces of the inner and outertubular members14 and16, define a first lumen40 (best seen in FIG. 5). As described in U.S. patent application Ser. No. 09/765,719 filed on Jan. 18, 2001 and entitled STENT DELIVERY SYSTEM WITH SPACER MEMBER, which is hereby incorporated by reference, splines18 can be provided between the inner and outertubular members14 and16.
• As shown in FIG. 3, the[0046]manifold housing20 carries anadmission port42 for injecting a contrast media into the interior of themanifold housing20. The interior of themanifold housing20 is in fluid flow communication with thefirst lumen40. Discharge ports41 (shown in FIGS. 2A and 2B) are formed through the outertubular member16 to permit contrast media to flow from thefirst lumen40 into the patient's body lumen.
• As shown in FIG. 3, an O-[0047]ring44 surrounds thestainless steel jacket32 between themanifold housing20 and lockhousing22. Upon threaded connection of themanifold housing20 to thelock housing22, the O-ring44 compresses against thestainless steel jacket32 in sealing engagement to prevent contrast media from flowing in any path other than through thefirst lumen40.
• As shown in FIGS. 1 and 3, the[0048]lock housing22 carries a threaded locking member (or lock nut)46 which can be turned to abut thestainless steel jacket32. Thelock nut46 can be released to free the stainless steel jacket to move axially. According, when thelock nut46 engages thejacket32, the jacket32 (and attached inner tubular member14) cannot move relative to thelock housing22,manifold housing20 or the outertubular member16. Upon release of thelock nut46, theinner tubular member14 and outertubular member16 are free to slide axially relative to one another between a transport position and a deploy position.
• First and[0049]second handles48,50 are secured to thelock housing22 andjacket32, respectively. In the transport position (shown in FIG. 2A), thehandles48,50 are spaced apart and the distal end of the outertubular member16 forms a sheath that covers thestent attachment location26 to prevent premature deployment of thestent12. When thehandle48 is pulled rearwardly toward thehandle50, the outertubular member16 slides rearwardly or proximally relative to theinner tubular member14. Preferably, the outertubular member16 slides rearwardly a distance sufficient to fully expose thestent attachment location26 and permit thestent12 to freely expand toward its fully expanded diameter (see FIG. 2B). After such expansion, the stent delivery system can be proximally withdrawn through the expanded stent and removed.
• As shown in FIG. 3, the[0050]first handle48 is rotatably mounted on aflange22aof thelock housing22. Thefirst handle48 surrounds thestainless steel jacket32 and is freely rotatable about the longitudinal axis of thejacket32 and freely rotatable about theflange22a. Thefirst handle48 is axially affixed to thelock housing22 such that axial forces applied to thefirst handle48 are transmitted through thelock housing22 andmanifold housing20 to the outertubular member16 to axially move theouter tubular16. However, rotary action of thefirst handle48 about the axis of thestainless steel jacket32 is not transmitted to thehousings20,22 or to the outertubular member16 by reason of the free rotation of thefirst handle48 onflange22a.
• As shown in FIG. 4, the[0051]second handle50 is mounted on ananchor52 that is bonded to thestainless steel jacket32 through any suitable means (such as by use of adhesives). Theanchor52 includes aflange52athat is radial to the axis of thestainless steel jacket32. Thesecond handle50 is mounted on theflange52aand is free to rotate on theanchor52 about the axis of thestainless steel jacket32. However, axial forces applied to thehandle50 are transmitted to thestainless steel jacket32 which, being bonded to theinner tubular member14, results in axial movement of theinner tubular member14.
• With the handle construction described above, relative axial movement between the[0052]handles48,50 results in relative axial movement between the inner and outertubular members14,16. Rotational movement of either of thehandles48,50 does not affect rotational positioning of the inner or outertubular members14,16 and does not affect axial positioning of the inner andouter tubes14,16.
• The free rotation of the[0053]handles48,50 results in ease of use for a physician who may position his or her hands as desired without fear of interfering with any axial positioning of the inner and outertubular members14,16. The spacing between thehandles48,50 is equal to the stroke between the transport position and the deploy position of thetubular members14,16. As a result, the spacing permits the operator to have ready visual indication of the relative axial positioning between the inner and outertubular members14,16. This relative axial positioning can be fixed by engaging thelock nut46. In any such positioning, contrast media can be injected through theadmission port42 into thechamber40 with the contrast media flowing out of theside ports41 into the body lumen to permit visualization under fluoroscopy.
• With stent deployment systems having premounted stents of various axial lengths, the positioning of the[0054]second handle50 on thestainless steel jacket32 can be selected at time of assembly so that a spacing S (see FIG. 1) between thehandles48,50 corresponds to the length of thestent12 carried on the stent deployment system. For example, in a preferred embodiment, the spacing S is about10 millimeters longer than the deployed length of the stent. Accordingly, the user will know that the outertubular member16 has been fully retracted when thehandles48,50 have been pushed completely together to completely release thestent12. Also, the freely rotatable handles48,50 are easy to hold from any angle without slippage. Thelock nut46 ensures that thestent12 will not deploy prematurely.
• A concern with existing delivery systems for self-expanding stents is control of stent delivery. For example, due to their elastic characteristics, self-expanding stents have a tendency to propel themselves axially outwardly from their restraining sheaths before the sheaths have been completely retracted. When this occurs, control of stent placement is compromised since the stent may overshoot the desired deployment site. Further, once the stent has been completely deployed, subsequent adjustment of the stent deployment location can be difficult because re-sheathing typically cannot be readily accomplished.[0055]
• To address the above concerns, the[0056]delivery system10 is preferably equipped with an interlock configuration that constrains relative axial movement between thestent12 and theinner tube14 until after thesheath16 has been fully retracted. For example, when thestent12 is mounted on theinner tube14 and restrained in the compressed orientation by thesheath16 as shown in FIG. 2A, a first interlock geometry (e.g.,male interlock structures82 as shown in FIG. 2A) located at the proximal end of thestent12 interlocks with a second interlock geometry (e.g.,female interlock structures84 as shown in FIG. 2A) defined by the proximal marker27 (also referred to as a collar). The interlock geometries remain interlocked to constrain axial movement of thestent12 until after the sheath has been retracted beyond a predetermined location (e.g., theproximal-most end12aof the stent12). When thesheath12 has been retracted beyond the predetermined location, the interlock geometry of thestent12 is allowed to expand. As the interlock geometry of the stent expands, the interlock geometry of the stent disengages from the interlock geometry of themarker27 thereby allowing theinner tube14 of the catheter to be moved axially relative to the stent without interference from the interlock geometries.
• FIGS. 6A and 6B illustrate the[0057]proximal end12aof thestent12 in relation to themarker27 located at the proximal end of theattachment location26. In FIGS. 6A and 6B, thestent12 and themarker27 have been cut longitudinally and laid flat. Thestent12 has a length L and a circumference C. In FIG. 6A, themarker27 and thestent12 are shown disengaged from one another. In FIG.6B marker27 and thestent12 are shown interlocked. In both FIGS. 6A and 6B, the stent is in the reduced diameter configuration. Similarly, the stents depicted in FIGS.7-15B are shown in the reduced diameter orientation.
• Referring to FIG. 6A, the[0058]stent12 includes a plurality of struts86 (i.e., reinforcing members). At least some of thestruts86 have free terminal ends that define the proximal and distal ends12aand12bof thestent12. Male interlock structures82 (i.e., keys) are provided at the free terminal ends of thestruts86. As shown in FIG. 6A, themale interlock structures82 include enlargements in the form of circular projections. The circular projections includeinterlock portions88 that project outwardly from thestruts86 in a circumferential direction (i.e., in a direction coinciding with the circumference C of the stent12). Theinterlock portions88 include interlock surfaces90 that face in an axial direction. The phrase “face in an axial direction” will be understood to mean that least a vector component of thesurface90 is perpendicular with respect to a longitudinal axis AA of thestent12. Thus, thesurface90 need not be completely perpendicular relative to the longitudinal axis of thestent12 to be construed as facing in an axial direction. In other words, a surface aligned at oblique angle relative to the longitudinal axis of thestent12 shall also be construed as facing in an axial direction since such surface has a vector component that is perpendicular relative to the longitudinal axis of the stent.
• As best shown schematically in FIG. 6C, the[0059]male interlock structures82 are preferably positioned within a region defined between an inner diameter D1 and an outer diameter D2 of thestent12. This is preferably true regardless of whether thestent12 is in the expanded diameter orientation or the reduced diameter orientation. Preferably, at least portions of the interlock surfaces90 are located within 5 millimeters of theproximal end12aof thestent12. More preferably, at least portions of the interlock surfaces90 are located within 3 millimeters of theproximal end12aof thestent12. Most preferably, at least portions of the interlock surfaces90 are located within 2 millimeters of theproximal end12aof thestent12.
• Referring to FIG. 6A, the[0060]stent12 includes a lumen reinforcing structure including a plurality ofstruts13 adapted to define open cells15 (best shown in FIG. 2B) when thestent12 is deployed. Preferably, themale interlock structures82 are located within 5 millimeter of thestruts13 that define theopen cells15. More preferably, themale interlock structures82 are located within 4, 3 or 2 millimeters of thestruts13 that define theopen cells15. Most preferably, themale interlock structures82 are located within 1 millimeter of thestruts13 that define theopen cells15. Because themale interlock structures82 are located relatively close to the structure defining theopen cells15, during deployment of thestent12, themale interlock structures82 will expand radially outwardly simultaneously with the radial expansion of at least a portion of the cell defining structure. When thestent12 is expanded, theinterlock structures82 are preferably maintained generally within a boundary defined by the inner and outer diameters of the cell defining portion of the stent, and preferably theinterlock structures82 are not biased or angled radially outwardly relative to the cell defining portion.
• Still referring to FIGS. 6A and 6B, the[0061]marker27 has an axialdistal edge29 facing theproximal end12aofstent12. Female interlock structures84 (i.e., sockets, openings, keyways, etc.) are defined by themarker27 adjacent theedge29. Thefemale interlock structures84 are configured to have a complimentary mating geometry with respect to themale interlock structures82 of thestent12. For example, similar to themale interlock structures82, thefemale interlock structures84 are shown having generally rounded or circular shapes. Each of thefemale interlock structures84 includes interlock surfaces92 that face in an axial direction.
• The geometry of the[0062]female interlock structures84 is selected to mate with the predetermined geometry of the stentproximal end12asuch that thestent12 and themarker27 can be axially coupled or interlocked when thestent12 is compressed at the mountinglocation26. When the male andfemale interlock structures82 and84 are interlocked, the interlock surfaces90 and92 oppose and circumferentially overlap one another (see FIG. 6B) such that the stent is restricted from distal movement relative to themarker27.
• With the specific embodiment shown, the[0063]stent12 andcollar27 are rotary coupled such that thestent12 andcollar27 are restricted from relative rotary motion (i.e., about axis X-X) when thestent12 is in the collapsed state. The predetermined stent geometry of theinterlock structures82 and the complementary mating geometry of thecollar27 do not restrict relative radial motion. Namely, as the self-expandingstent12 expands radially, themale interlock structures82 are free to radially move out of thefemale interlock structures84. After such motion, thestent12 is no longer coupled to thecollar27 and thestent12 andcollar27 are free to move axially, radially or transversely to one another.
• With the embodiment thus described, the mating features of the[0064]stent12 andcollar27 prevent premature discharge of thestent12 from astent attachment location26. As theouter sheath16 is retracted, the sheathdistal end16bexposes thedistal end12bof thestent12. At this point, the exposeddistal end12bof thestent12 is free for limited expansion restrained by the remainder of thestent12 being covered by thesheath16 and by the attachment of the stentproximal end12ato theproximal marker27.
• Further retraction of the[0065]sheath16, permits still further expansion of thestent12. As the sheathdistal end12bapproaches the stentproximal end12a, the expansion of the stent material tends to urge thestent12 to squeeze out of the small portion of thesheath16 now covering thestent12. However, this propensity is overcome by the attachment of the stentproximal end12ato thecollar27 since any such ejection of thestent12 would require axial separation of thestent12 andcollar27. Such movement is prevented by themale interlock structures82 and thefemale interlock structures84.
• Therefore, as long any portion of the[0066]sheath16 overlies the male andfemale interlock structures82 and84, theproximal end12aof thestent12 cannot expand and cannot axially move away from thecollar27. Accordingly, thestent12 is not released from theattachment location26 until the physician has fully retracted thesheath16 with the sheathdistal end16bretracted proximal to the proximal end ofstent attachment location26. The sheathdistal end16bis provided with amarker16b′ (shown in FIGS. 2A and 2B) to permit visualization of the relative position of the sheathdistal end12band themarkers27,28 of thestent attachment location26.
• With the structure and operation thus described, the physician has greater control of the release of the[0067]stent12. More accurate stent positioning is attained. As long as even a small portion of thesheath16 is not fully retracted (e.g., at least 1 mm extends distally to theproximal end12aof the stent12) the axial position of thestent12 can be adjusted by advancing or retracting theinner tubular member14. Also, as long as a small portion of thesheath16 remains covered by the sheath16 (e.g., at least 1 mm), thestent12 can be readily re-sheathed by moving thesheath16 in a distal direction.
• In the embodiment of FIGS. 6A and 6B, the female and[0068]male interlock structures82 and84 have complementary mating geometries. It will be appreciated that in alternative embodiments, the female and male interlock structures need not have complementary/identical shapes. Instead, to provide an interlock, it is only necessary for a portion of the male interlock to be received in the female interlock such that mechanical interference or overlap between the interlocks prevents the interlocks from being axially separated. This can be accomplished without having identical mating shapes.
• As described above, the[0069]interlock structure84 of theinner tube14 is provided on theproximal marker27. It will be appreciated that theinterlock structure84 need not be the same element as the marker but could be a separate part. As a separate part, the interlock structure could be integrally formed/connected with the exterior of theinner tube14, connected to the outer surface of the inner tube by conventional techniques (e.g., adhesive, fasteners, fusion bonding, etc.), or be connected to the outer surface of theinner tube14 by one or more intermediate members. Further, the embodiment of FIGS. 6A and 6B shows that the interlock between thestent12 and thetube14 is provided at theproximal end12aof thestent12b. It will be appreciated that for certain embodiments, the interlock between theinner tube14 and thestent12 can be provided at thedistal end12bof the stent12 (e.g., for a distally retractable sheath). Moreover, while the embodiment of FIGS. 6A and 6B shows interlock structures provided at all of the proximal ends of thestruts86, the invention is not so limited. For example, in some embodiments, only some of thestruts86 may include interlock structures. While in certain embodiments it may be desirable to use only one interlock structure at the end of thestent12, it is preferable to use at least two separate/discrete interlock structures uniformly spaced about the circumference of the stent. It is more preferable to use at least 4 separate/discrete interlock structures that are preferably uniformly spaced about the circumference of the stent.
• The[0070]collar27 may be provided with indicia to indicate to a physician the position of the collar27 (and hence the stent12) when the combination is in a patient's vessel and is being visualized under fluoroscopy. In the embodiment of FIGS. 6A and 6B, the indicia is shown ascutouts15 in thecollar27. FIG. 7 shows acollar27′ having indicia in the form ofproximal projections15′ off of the proximal edge of thecollar27′. FIG. 8 shows acollar27′ having indicia in the form oftriangular notches15′ defined at the proximal edge of thecollar27′. In the embodiments shown, theindicia15,15′ and15″ are spaced apart circumferentially on theirrespective collars27,27′ and27″ so that the indicia are 180 degrees apart.
• In the embodiment of FIGS. 6A and 6B, the pattern and shape of the[0071]male interlock structures82 and thefemale interlock structures84 are symmetrical about the stent axis X-X. As a result, thestent12 can be affixed to thecollar27 in any one of a plurality of rotary alignments about axis X-X.
• FIG. 9 illustrates an embodiment of a[0072]collar127 andstent112 where the symmetrical pattern is interrupted. In the example of FIG. 9, a single unique key117 is provided (which, in the example shown, has a square geometry compared to the circular geometry of remaining male interlock structures182). Similarly, thecollar127 has aunique keyway117ato mate with the unique key117. As a result, thestent112 can only be affixed to thecollar127 in one rotary alignment.
• In all of the above embodiments, once the position of a stent is fixed to a collar, a non-symmetrical stent feature (e.g., an opening for placement at a bifurcation in a vessel) can be aligned with the indicia (or, if desired, a single indicia can be provided on the collar). Therefore, a physician can easily visualize the position of any non-symmetrical stent feature.[0073]
• FIG. 10 illustrates an embodiment of a[0074]stent212 andradiopaque collar227 having another interlock configuration. Thecollar227 hascircumferential slots228 for assisting in adhesively bonding thecollar227 to the outer surface of theinner tube14. Thestent212 has proximal anddistal ends212aand212b. The stent also includes proximal end struts286ahaving free ends at whichmale interlock structures282 are formed. Themale interlock structures282 are formed by notches cut into the proximal end struts286a. Themale interlock structures282 include axially facing interlock surfaces290 that face in a distal direction. Preferably, thesurfaces290 are located within 5 millimeters of theproximal end212aof thestent212, and within 1, 2, 3, 4 or 5 millimeters of a cell defining portion of the stent.
• The[0075]collar227 includesfemale interlock structures284 in the form of sockets. The sockets are partially defined by projections adapted to fit within the notches cut into the proximal end struts286a. The projections define axially facing interlock surfaces292 that face in a proximal direction. When the male andfemale interlock structures282 and284 are interlocked, thesurfaces290 and292 oppose one another to prevent themale interlock structures282 from being axially withdrawn from thefemale interlock structures284.
• FIG. 11 illustrates an embodiment of a[0076]stent312 andradiopaque collar327 having another interlock configuration. Thecollar327 hascircumferential slots328 for assisting in adhesively bonding thecollar327 to the outer surface of theinner tube14. Thestent312 has proximal anddistal ends312aand312b. The stent also includes proximal end struts386ahaving free ends at whichmale interlock structures382 are formed. Themale interlock structures382 are formed by enlarged heads (i.e., protuberances or keys) located at the ends of the end struts386a. Themale interlock structures382 include axially facing interlock surfaces390 that face in a distal direction. Preferably, thesurfaces390 are located within 5 millimeters of theproximal end312aof thestent312, and within 1, 2, 3, 4 or 5 millimeters of a cell defining region of the stent. Thecollar327 includesfemale interlock structures384 in the form of sockets. Thefemale interlock structures384 include axially facing interlock surfaces392 that face in a proximal direction. When the male andfemale interlock structures382 and384 are interlocked, thesurfaces390 and392 oppose one another to prevent themale interlock structures382 from being axially withdrawn from thefemale interlock structures384.
• FIG. 12 illustrates an embodiment of a[0077]stent412 includingfemale interlock structures484. Thefemale interlock structures484 preferably include distally facing interlock surfaces492 located within 5 mm of aproximal end412aof thestent412 and within 1, 2, 3, 4 or 5 millimeters of a cell defining region of the stent. Thefemale interlock structures484 are sized to receivemale interlock structures482 in the form of rectangular posts. Preferably, the posts are connected to the outer surface of the inner tube14 (e.g., integrally or otherwise). The posts define proximally facing interlock surfaces490. When the female andmale interlock structures484 and482 are coupled, thesurfaces490 and492 engage each other to prevent distal movement of thestent412 relative to the posts.
• FIG. 13 illustrates an embodiment of a[0078]stent512 includingmale interlock structures582 in the form of hooks. Themale interlock structures582 preferably include distally facing interlock surfaces590 located within 5 mm of aproximal end512aof thestent512 and within 1, 2, 3, 4 or 5 millimeters of a cell defining region of the stent. Themale interlock structures582 are sized to fit within female interlock structures584 defined by acollar527. The female interlock structures584 define proximally facing interlock surfaces592. When the female andmale interlock structures584 and582 are coupled, thesurfaces590 and592 engage each other to prevent distal movement of thestent512 relative to thecollar527.
• FIGS. 14A and 14B illustrate an embodiment of a[0079]stent612 includingfemale interlock structures684 in the form of longitudinal slots between or within struts. Thefemale interlock structures684 preferably include distally facing interlock surfaces692 (e.g., defined by the proximal ends of the slots) located within 5 mm of aproximal end612aof thestent612 and within 1, 2, 3, 4 or 5 millimeters of a cell defining region of the stent. Thefemale interlock structures684 are sized to receivemale interlock structures682 in the form of linear posts. Preferably, the posts are connected to the outer surface of the inner tube14 (e.g., integrally or otherwise). The posts define proximally facing interlock surfaces690 (e.g., at the proximal ends of the posts). When the female andmale interlock structures684 and682 are coupled as shown in FIG. 14B, thesurfaces690 and692 engage each other to prevent distal movement of thestent612 relative to the posts.
• FIGS. 15A and 15B illustrate an embodiment of a[0080]stent712 includingfemale interlock structures784 in the form of circular openings defined through enlarged strut ends of thestent712. Thefemale interlock structures784 preferably include distally facing interlock surfaces792 located within 5 mm of aproximal end712aof thestent712 and within 1, 2, 3, 4 or 5 millimeters of a cell defining region of the stent. Thefemale interlock structures784 are sized to receivemale interlock structures782 in the form of cylindrical posts or pins. Preferably, the posts are connected to the outer surface of the inner tube14 (e.g., integrally or otherwise). The posts define proximally facing interlock surfaces790. When the female andmale interlock structures784 and782 are coupled as shown in FIG. 15B, thesurfaces790 and792 engage each other to prevent distal movement of thestent712 relative to the posts.
• FIGS. 16A and 16B show a[0081]stent delivery system10′ that is another embodiment of the present invention. Thedelivery system10′ includes aninner member14′ and anouter sheath16′. Theinner member14′ includes a flexibledistal tip30′ and astent mounting location26′. Proximal anddistal markers27′ and28′ are located on opposite sides of the mountinglocation26′. Theproximal marker27′ includes interlock structures in the form ofreceivers84′ or receptacles. Thereceivers84′ are adapted to receive and interlock with interlock structures in the form ofenlargements82′ provided at the proximal end ofself expanding stent12′. Theenlargements82′ are preferably within 1, 2, 3, 4 or 5 millimeters ofcell defining structures83′ of thestent12′.
• While the various embodiments of the present invention have related to stents and stent delivery systems, the scope of the present invention is not so limited. For example, while particularly suited for stent delivery systems, it will be appreciated that the various aspects of the present invention are also applicable to systems for delivering other types of self-expandable implants. By way of non-limiting example, other types of self-expanding implants include anastomosis devices, blood filters, grafts, vena cava filters, percutaneous valves, or other devices. Also, while it is preferred for the interlocks of the present invention to be within 5 millimeters of an end of their corresponding implant to enhance deployment control, larger spacings could be used for certain applications. Similarly, while it is preferred for the interlocks to be within 5, 4, 3, 2 or 1 millimeters of cell defining regions of the stents, other spacings could be used in certain alternative embodiments.[0082]
• It has been shown how the objects of the invention have been attained in a preferred manner. Modifications and equivalents of the disclosed concepts are intended to be included within the scope of the claims.[0083]

Claims (43)

What is claimed is:

1. An implant delivery system comprising:

a catheter including an elongated member having an implant mounting location;

an expandable implant mounted on the elongated body at the implant mounting location, the implant being expandable from a compressed orientation to an expanded orientation, the implant including first and second ends;

a sheath mounted on the elongated member, the sheath being positionable in a transport position in which the sheath covers the implant mounted at the implant mounting location, the sheath also being positionable in a deploy position in which the implant is exposed;

the implant including a first interlock structure and the elongated body including a second interlock structure, the first and second interlock structures interlocking to constrain axial movement of the implant relative to the elongated member when the implant is at least partially within the sheath, and the first and second interlock structures not constraining radial expansion of the implant;

one of the first and second interlock structures including a male interlock structure and the other of the first and second interlock structures including a female interlock structure adapted to receive the male interlock structure when the implant is in the compressed orientation;

the implant including a cell defining region; and

at least a portion of the first interlock structure being positioned within 5 millimeters of the first end of the implant and within 5 millimeters of the cell defining region of the implant.

2. The implant delivery system ofclaim 1, wherein the implant comprises a stent.

3. The implant delivery system ofclaim 1, wherein at least a portion of the first interlock structure is positioned within 2 millimeters of the first end of the implant.

4. The implant delivery system ofclaim 1, wherein the elongated body includes a radiopaque marker positioned adjacent to the implant mounting location, and wherein the marker defines the second interlock structure.

5. The implant delivery system ofclaim 1, wherein the first end of the implant is a proximal end of the implant.

6. The implant delivery system ofclaim 1, wherein the implant includes a plurality of separate first interlock structures having at least portions positioned within 5 millimeters of the first end, and wherein the elongated body includes a plurality of second interlock structures for interlocking with the first interlock structures.

7. The implant delivery system ofclaim 1, wherein the first interlock structure is the male interlock structure and the second interlock structure is the female interlock structure.

8. The implant delivery system ofclaim 7, wherein the male interlock structure includes an enlargement positioned at the first end of the implant.

9. The implant delivery system ofclaim 8, wherein the implant includes a plurality of enlargements at the first end of the implant.

10. The implant delivery system ofclaim 8, wherein the male interlock structure includes a circumferential projection positioned at the first end of the implant.

11. The implant delivery system ofclaim 10, wherein the implant includes a plurality of the circumferential projections at the first end of the implant.

12. The implant delivery system ofclaim 1, wherein the first interlock structure is the female interlock structure and the second interlock structure is the male interlock structure.

13. The implant delivery system ofclaim 12, wherein the implant includes struts, and the female interlock structure includes a post opening defined through at least one of the struts.

14. The implant delivery system ofclaim 13, wherein the implant includes a plurality of the post openings.

15. The implant delivery system ofclaim 13, wherein the implant includes struts, and the female interlock structure includes an opening between the struts.

16. The implant delivery system ofclaim 1, wherein the first interlock structure is within 2 millimeters of the cell defining region of the implant.

17. The implant delivery system ofclaim 1, wherein the first interlock structure is within 1 millimeter of the cell defining region of the implant.

18. The implant delivery system ofclaim 1, wherein the elongated member extends completely through the implant.

19. The implant delivery system ofclaim 1, wherein the cell defining region of the implant includes a boundary defined by an inner diameter and an outer diameter of the implant, and wherein the first interlock structure stays generally within the boundary after the implant has been deployed.

20. The implant delivery system ofclaim 1, wherein the first interlock structure is not radially outwardly biased relative to the cell defining region of the implant.

21. An implant delivery system comprising:

a catheter including an elongated member having an implant mounting location;

an expandable implant mounted on the elongated body at the implant mounting location, the implant being expandable from a compressed orientation to an expanded orientation, the implant including first and second ends;

a sheath mounted on the elongated member, the sheath being positionable in a transport position in which the sheath covers the implant mounted at the implant mounting location, the sheath also being positionable in a deploy position in which the implant is exposed;

the implant including a cell defining region, the implant also including a plurality of struts at least some of which have terminal ends defining the first end of the implant, the implant also including at least two enlargements positioned at the terminal ends of the struts, the enlargements being located within 5 millimeters of the cell defining region of the implant; and

the elongated body including receptacles that receive the enlargements to constrain axial movement of the implant relative to the elongated member when the implant is at least partially within the sheath.

22. The implant delivery system ofclaim 21, wherein the elongated body includes a radiopaque marker positioned adjacent to the implant mounting location, and wherein the marker defines the receptacles.

23. The implant delivery system ofclaim 21, wherein the first end of the implant is a proximal end of the implant.

24. The implant delivery system ofclaim 21, wherein the enlargements are within 2 millimeters of the cell defining region of the implant.

25. The implant delivery system ofclaim 21, wherein the enlargements are within 1 millimeter of the cell defining region of the implant.

26. The implant delivery system ofclaim 21, wherein the elongated member extends completely through the implant.

27. The implant delivery system ofclaim 21, wherein the cell defining region of the implant includes a boundary defined by an inner diameter and an outer diameter of the implant, and wherein the enlargements stay generally within the boundary after the implant has been deployed.

28. The implant delivery system ofclaim 21, wherein the enlargements are not radially outwardly biased relative to the cell defining region of the implant.

29. An implant delivery system comprising:

a catheter including an elongated member having an implant mounting location;

an expandable implant mounted on the elongated body at the implant mounting location, the implant being expandable from a compressed orientation to an expanded orientation, the implant including first and second ends;

a sheath mounted on the elongated member, the sheath being positionable in a transport position in which the sheath covers the implant mounted at the implant mounting location, the sheath also being positionable in a deploy position in which the implant is exposed;

the implant including a cell defining region and first and second ends, the implant also including at least two female male interlock structures positioned within 5 millimeters of the first end of the implant and within 5 millimeters of the cell defining region of the implant; and

the elongated body including male interlock structures that are received within the female interlock structures to constrain axial movement of the implant relative to the elongated member when the implant is at least partially within the sheath, the male and female interlock structures not constraining radial expansion of the implant.

30. The implant delivery system ofclaim 29, wherein the elongated body includes a radiopaque marker positioned adjacent to the implant mounting location, and wherein the marker includes the male interlock structures.

31. The implant delivery system ofclaim 29, wherein the first end of the implant is a proximal end of the implant.

32. The implant delivery system ofclaim 29, wherein the female interlock structures are within 2 millimeters of the cell defining region of the implant.

33. The implant delivery system ofclaim 29, wherein the female interlock structures are within 1 millimeter of the cell defining region of the implant.

34. The implant delivery system ofclaim 29, wherein the elongated member extends completely through the implant.

35. An implant delivery system comprising:

a catheter including an elongated member having an implant mounting location;

an expandable implant mounted on the elongated body at the implant mounting location, the implant being expandable from a compressed orientation to an expanded orientation, the implant including first and second ends;

a sheath mounted on the elongated member, the sheath being positionable in a transport position in which the sheath covers the implant mounted at the implant mounting location, the sheath also being positionable in a deploy position in which the implant is exposed;

a marker attached to the elongated member, the marker including structure that interlocks with the implant to constrain axial movement of the implant relative to the elongated member when the implant is at least partially within the sheath.

36. An implant delivery system comprising:

a catheter including an elongated member having an implant mounting location;

an expandable implant mounted on the elongated body at the implant mounting location, the implant being expandable from a compressed orientation to an expanded orientation, the implant including first and second ends;

a sheath mounted on the elongated member, the sheath being positionable in a transport position in which the sheath covers the implant mounted at the implant mounting location, the sheath also being positionable in a deploy position in which the implant is exposed;

the implant including a first interlock structure and the elongated body including a second interlock structure, the first and second interlock structures interlocking to constrain axial movement of the implant relative to the elongated member when the implant is at least partially within the sheath, and the first and second interlock structures not constraining radial expansion of the implant;

one of the first and second interlock structures including a male interlock structure and the other of the first and second interlock structures including a female interlock structure adapted to receive the male interlock structure when the implant is in the compressed orientation; and

at least a portion of the first interlock structure being positioned within 5 millimeters of the first end of the implant, and the elongated member extending through the implant at the implant mounting location.

37. The implant delivery system ofclaim 36, wherein at least a portion of the first interlock structure is positioned within 2 millimeters of the first end of the implant.

38. An implant delivery system comprising:

a catheter including an elongated member having an implant mounting location;

an expandable implant mounted on the elongated body at the implant mounting location, the implant being expandable from a compressed orientation to an expanded orientation, the implant including first and second ends;

a sheath mounted on the elongated member, the sheath being positionable in a transport position in which the sheath covers the implant mounted at the implant mounting location, the sheath also being positionable in a deploy position in which the implant is exposed;

the implant including a first interlock structure and the elongated body including a second interlock structure, the first and second interlock structures interlocking to constrain axial movement of the implant relative to the elongated member when the implant is at least partially within the sheath, and the first and second interlock structures not constraining radial expansion of the implant;

one of the first and second interlock structures including a male interlock structure and the other of the first and second interlock structures including a female interlock structure adapted to receive the male interlock structure when the implant is in the compressed orientation;

the implant including a cell defining region that includes a boundary defined by an inner diameter and an outer diameter of the implant, the first interlock structure being configured to stay generally within the boundary after the implant has been deployed; and

at least a portion of the first interlock structure being positioned within 5 millimeters of the first end of the implant.

39. The implant delivery system ofclaim 38, wherein at least a portion of the first interlock structure is positioned within 2 millimeters of the first end of the implant.

40. A method for deploying a self-expandable implant with a deployment system, the deployment system including a sheath for holding the implant in a compressed orientation, the implant including first and second ends, the implant also including an interlock surface positioned between inner and outer diameters of the implant, the interlock surface being located within 5 millimeters of the first end of the implant, the method comprising:

generating relative movement between the implant and the sheath to expose the implant;

engaging the interlock surface with a retainer as the implant is exposed to prevent the implant from prematurely exiting the sheath; and

after the implant has been exposed beyond the interlock surface, disengaging the interlock surface from the retainer by self-expanding the implant, wherein the interlock surface disengages from the retainer simultaneous with the expansion of a cell defining portion of the implant.

41. The method of claim40, wherein the implant is a stent.

42. The method of claim40, wherein the interlock surface is within 2 millimeters of the first end of the implant.

43. The method of claim40, wherein the first end of the implant is a proximal end of the implant and the second end of the implant is a distal end of the implant.

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