Abstract:
Delivery systems for delivering and deploying expandable intraluminal medical devices at a desired point of treatment within a body vessel are provided. The delivery systems comprise a sheath member and an inner member slideably disposed within a cavity formed by the sheath member. An expandable intraluminal medical device is disposed about the inner member and is initially positioned within the delivery system. A means for preventing axial movement of the inner member holds the inner member in position so that, while the delivery system and medical device are positioned at a desired point of treatment, the sheath member can be retracted while an axial position of the inner member is substantially maintained.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present application claims priority to the provisional patent application identified by U.S. Ser. No. 60/684,042, filed on May 24, 2005, the entire content of which is hereby expressly incorporated herein by reference. 
     
    
     FIELD  
       [0002]     The invention relates to delivery systems for placement of self-expandable intraluminal medical devices within a body vessel.  
       BACKGROUND  
       [0003]     Minimally invasive medicine, the practice of gaining access to a body vessel, duct, or organ using a guiding member to facilitate the subsequent introduction of other medical devices, has been evolving since the Seldinger technique was first popularized during the 1950&#39;s and 1960&#39;s. Self-expandable intraluminal medical devices are frequently used in a variety of minimally invasive procedures. For example, self-expandable stents are used to provide support to various vessels and ducts in the circulatory and the gastrointestinal systems. Also, prosthetic valves are gaining popularity as tools for supplementing and/or replacing natural valves in a variety of locations within the body, such as veins and the heart and its associated vessels.  
         [0004]     When placing medical devices within a body vessel, it is desirable to place a medical device as close to the desired point of treatment as possible. There are delivery systems known in the art that utilize a pushing function to move a medical device from the system to a position within a body vessel at a point of treatment. This method of delivery requires the delivery system operator to estimate the point at which a device will be deployed. Further, the operator is required to position the system appropriately in the body vessel to deliver the medical device as near as possible to the point of treatment.  
         [0005]     There is a need for delivery systems that offer more accurate delivery of medical devices near the desired point of treatment, especially delivery systems adapted for placement of self-expandable intraluminal medical devices.  
       SUMMARY OF EXEMPLARY EMBODIMENTS  
       [0006]     The invention provides medical device delivery systems. A delivery system according to one exemplary embodiment comprises a sheath member defining a first passageway, an inner member slidably disposed within a distal cavity of the first passageway, a fluid that substantially prevents movement of the inner member within the distal cavity, and a groove on the first inner surface of the sheath member. The groove prevents the inner member from completely exiting the sheath member as the sheath member is retracted. A self-expandable intraluminal medical device is disposed on a mounting region of the inner member the sheath member has an exchange port defined by a circumferential wall.  
         [0007]     In another exemplary embodiment, a pusher is used rather than a fluid. The pusher can be used to provide resistance against movement of the inner member within the distal cavity.  
         [0008]     Additional understanding of the invention can be obtained with review of the detailed description of exemplary embodiments, below, and the appended drawings illustrating exemplary embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a sectional view of a delivery system according to a first exemplary embodiment.  
         [0010]      FIG. 2  is a sectional view of the delivery system illustrated in  FIG. 1  partially disposed within a body vessel. The delivery system is shown in a stage of deployment with the self-expandable intraluminal medical device fully deployed.  
         [0011]      FIG. 3  is a sectional view of a delivery system according to a second exemplary embodiment. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0012]     The following detailed description and the appended drawings describe and illustrate exemplary embodiments of the invention for purposes of enabling one of ordinary skill in the relevant art to make and use the invention. The description and drawings are not intended to limit the scope of the invention, or its protection, in any manner.  
         [0013]      FIGS. 1 and 2  illustrate a delivery system  10  according to a first exemplary embodiment. Delivery system  10  comprises a sheath member  12  defining a first passageway  14 , an inner member  16  slidably disposed within a distal cavity  18  of the first passageway  14  of the sheath member  12 , a fluid  20  that substantially prevents movement of the inner member  16  within the distal cavity  18  of the sheath member  12 , and a groove  22  on a first inner surface  24  of the sheath member  12 . A self-expandable intraluminal medical device  28  is disposed on a mounting region  30  of the inner member  16 . The groove  22  prevents the inner member  16  from completely exiting the sheath member  12 .  
         [0014]     The entire delivery system  10  can be advanced over a wire guide  46  to navigate in a body vessel and to a point of treatment for the deployment of the self-expandable intraluminal medical device  28 . The use of wireguides in the placement of delivery systems and intraluminal medical devices within body vessels is well known in the art and will not be described in detail herein.  
         [0015]     The sheath member  12  can be any suitable tubular member, such as a sheath formed of plastic or other suitable material. Other examples of suitable tubular members include introducers, guiding catheters, and endoscopes. The sheath member  12  has the first inner surface  24  and a first outer surface  26  and defines the first passageway  14  that extends between a first proximal end  32  and a first distal end  34 . The first passageway  14  provides the distal cavity  18  within which other components of the delivery system  10  can be disposed. In the illustrated embodiment, the distal cavity  18  is a portion of and is continuous with the first passageway  14 . It is understood that, while the sheath member  12  is illustrated with a constant inner diameter along its length, varying inner diameters can be used, including varying inner diameters that, in effect, at least partially separate the distal cavity  18  from the remainder of the first passageway  14 .  
         [0016]     A reservoir unit  36  that contains a fluid  20  is slidably disposed within the first proximal end  32  of the sheath member  12 . The reservoir unit  36  is discussed in further detail below. The first proximal end  32  of the sheath member  12  also comprises a first seal  38  that prevents the fluid  20  from escaping the sheath member  12 .  
         [0017]     Also, a grip  40  is located on the first proximal end  32  on the outer surface  26  of the sheath member  12 . The grip  40  can be any suitable configuration that allows the user to grasp the sheath member  12  and retract it proximally away from the point of treatment. Further, the grip  40  can be integrally formed with the sheath member  12  or separately formed and attached. As illustrated by  FIGS. 1 and 2 , the grip  40  can form finger holes. The grip  40  could also be undulations ergonomically designed to be grasped by the user. The grip could also be a portion of the sheath member  12  with a different surface or texture to be grasped by the user. These elements, however, are not required and the sheath member  12  can indeed comprise a simple tubular body so long as the user is able to retract the sheath member  12  as necessary to operate the system.  
         [0018]     The sheath member  12  in the illustrated embodiment is adapted for use in short-wire based devices and techniques, such as rapid exchange and remote uncoupling devices and techniques, which are adapted to allow the use of relatively short wireguides as compared to those used in standard over-the-wire devices and techniques. It is understood, though, that the invention can be utilized in both standard over-the-wire and short wire devices and techniques, including rapid exchange and remote-uncoupling based devices and techniques. In the illustrated embodiment, the sheath member  12  defines an exchange port  42  in its circumferential wall. The exchange port  42  comprises an opening that provides access from the external environment into the first passageway  14  of the sheath member  12  and a second seal  48  that prevents the fluid  20  from escaping the sheath member  12  during rapid exchange applications. The portion of the first passageway  14  extending between the exchange port  42  and the opening  44  at the first distal end  34  of the sheath member  12  provides a wire guide lumen that spans only a portion of the length of the sheath member  12 . In use, a wireguide  46  passes through the opening  44  at the first distal end  34  of the sheath member  12 , through the inner member  16 , into the first passageway  14 , and exits the sheath member  12  through the exchange port  42 . The inner member  16 , as described in more detail below, advantageously defines a wireguide lumen to facilitate this arrangement of a wireguide through the delivery system  10 . This configuration facilitates use of the delivery system  10  in rapid exchange techniques.  
         [0019]     As illustrated in  FIGS. 1 and 2 , the reservoir unit  36  is in fluid communication with the first passageway  14  at the first proximal end  32  of the sheath member  12 . The reservoir unit  36  comprises a chamber  50  further comprising a second inner surface  52  and a second outer surface  54  and containing the fluid  20 , a stem  56  with a second proximal end  58  and a second distal end  60 , a flange  66 , and a plunger  62 . The stem  56  defines a second passageway  64  that extends between the second proximal  58  and distal ends  60 .  
         [0020]     The stem  56  is fixed to the distal end of the chamber  50 . The stem  56  and chamber  50  may be integrally formed or formed separately and attached. The stem  56  is slidably disposed within the first passageway  14  at the first proximal end  32  of the sheath member  12 . The flange  66  located at the second distal end of the stem  56  is advantageously designed to prevent the stem  56  from completely exiting the first passageway  14  of the sheath member  12 . The first seal  38  on the first distal end  34  of the sheath member  12  interacts with the outside surface of the stem  56  to prevent fluid from escaping the first passageway  14  of the sheath member  12 . As best illustrated in  FIG. 1 , the first seal can interact with the flange  66  to prevent the stem  56  from completely exiting the first passageway  14  of the sheath member  12 .  
         [0021]     The flange  66  may be configured to allow removal of the stem  56  of the reservoir unit  36  from the first passageway  14  of the sheath member  12 . Also, there may be no flange  66  at all. Once the reservoir unit  36  has been removed from the sheath member  12 , a device may be attached to the first proximal end  32  of the sheath member  12  to provide a vacuum to draw the inner member  16  back into the sheath member  12  once the self-expandable intraluminal medical device  28  has been delivered to the point of treatment  82 . For example, the first proximal end  32  of the sheath member  12  could comprise a luer fitting adapted to connect with a syringe. The syringe could then be used to provide a vacuum within the sheath member  12  to withdraw the inner member  16  back into the sheath member  12 .  
         [0022]     The plunger  62  is slidably disposed within the chamber  50  of the reservoir unit  36 . The plunger  62  is advantageously designed to contact the second inner surface  52  of the chamber  50  to create a seal to prevent the fluid  20  from leaking past the plunger  62 . As the plunger  62  is depressed the fluid  20  is transferred into the stem  56  and further into the first passageway  14  of the sheath member  12  until the fluid  20  contacts the proximal flange  68  of the inner member  16 . By depressing the plunger  62  and transferring the fluid  20  into the stem, a fluid column is created within the first passageway  14  that maintains a pressure on a proximal flange  68  of the inner member  16 . The pressure exerted by the fluid column substantially prevents movement of the inner member  16  within the distal cavity  18  of the sheath member  12  as the sheath member  12  is retracted. This allows the intraluminal medical device  28  to be deployed substantially at a desired location in the body vessel after navigating the delivery system  10  to a part of the body vessel such that the intraluminal medical device  28  is positioned substantially at the desired location prior to deployment. In this manner, the delivery system  10  allows an intraluminal medical device  28  to be deployed substantially at the same location in a body vessel as the intraluminal medical device  28  is at once navigation through the vessel is completed. The plunger  62  does not return to its original position until withdrawn proximally by the user.  
         [0023]     The fluid  20  can be any fluid that will depend on a number of factors: materials of construction of the delivery system  10 , viscosity of the fluid, size of the delivery system  10 , cost of the fluid, and others. The fluid  20  could be, but is not limited to, saline, water, air, a gel, or a highly viscous fluid. The delivery system  10  can be prepackaged with the fluid  20  in the reservoir unit  36  or the fluid  20  can be packaged separately. Furthermore, prior to or during the implantation procedure the first passageway  14  of the sheath member  12  could be filled with the fluid  20  to ensure the fluid column is in place and contacting the proximal flange  68  of the inner member  16 . It is expected to be advantageous to fill the resevoir unit  36  and first passageway  14 , to the proximal flange  68  of the inner member  16 , completely with the fluid  20  at some point prior to use of the delivery system  10 . This can be done at the time of manufacture, in the procedure room immediately prior to use, or at any suitable time in between these periods.  
         [0024]     The inner surface  24  of the sheath member  12  defines the groove  22 . The groove  22  is located proximally to the opening  44  at the first distal end  32  of the sheath member  12 . The groove  22 , discussed in more detail below, prevents the inner member  16  from completely exiting the sheath member  12  as it is pulled away from the point of treatment  82 .  
         [0025]     The first passageway  14  of the sheath member  12  includes a distal cavity  18  that receives the inner member  16 . In the illustrated embodiment, the distal cavity  18  is a portion of and is continuous with the first passageway  14 . It is understood that, while the sheath member  12  is illustrated with a constant inner diameter along its length, that varying inner diameters can be used, including varying inner diameters that, in effect, at least partially separate the distal cavity  18  from the remainder of the first passageway  14 .  
         [0026]     The inner member  16  provides a structure for carrying the self-expandable intraluminal medical device  28 . The inner member  16  comprises a separate member from the sheath member  12  and is slidably disposed within the distal cavity  18  of the sheath member  12 . The inner member  16  comprises the proximal flange  68 , a distal tip  70 , a third proximal end  72 , a third distal end  74 , and the mounting region  30 . The inner member  16  defines a third passageway  76  that extends between the third proximal end  72  and the third distal end  74 . A portion of the wireguide  46  passes through the distal tip  70  at the third distal end  74  into the third passageway  76  and exits the inner member  16  through the proximal flange  68 . A third seal  78  located at the third proximal end  72  of the third passageway  76  allows the wireguide  46  to pass through the inner member  16  but prevents the fluid  20  from entering the third passageway  76  of the inner member  16  from the first passageway  14  of the sheath member  12 . The distal tip  70 , proximal flange  68 , and mounting region  30  may be unitarily formed or separately formed and attached. In this embodiment, the proximal flange  68  and distal tip  70  are continuous with the mounting region  30  of the inner member  16 .  
         [0027]     The distal tip  70  is the distal-most portion of the inner member  16 . The distal tip  70  advantageously includes a rounded or conical configuration at the third distal end  74  as it is the leading surface of the delivery system  10  during navigation through body vessels. The distal tip  70  is advantageously formed of a pliable material, such as an elastomeric material, that enables the distal tip  70  to safely maneuver through the body vessels.  
         [0028]     The proximal flange  68  is the third proximal end  72  of the inner member  16 . The proximal flange  68  advantageously comprises any configuration with a diameter large enough to contact the inner surface  24  of the sheath member  12  to create a seal and prevent the fluid  20  from passing the proximal flange  68 , yet allowing the inner member  16  to slidably move within the distal cavity  18  of the first passageway  14 . The proximal flange  68  is advantageously formed of a relatively rigid material such as a plastic or metal material that enables the proximal flange  68  to engage the groove  22  to prevent the inner member  16  from completely exiting the sheath member  12 .  
         [0029]     The mounting region  30  is formed of any suitable material, including plastics and metals. The mounting region  30  is of sufficient length to accommodate the self-expandable intraluminal medical device  28 . Any suitable type of self-expandable prosthetic device can be used with the delivery systems according to the invention, including self-expandable stents, prosthetic valves that include a self-expandable support frame, such as prosthetic valves for implantation in a vein (prosthetic venous valves), self-expandable filters, distal protection devices, vessel occluders, and other self-expandable devices. Suitable self-expandable medical devices for use with delivery systems according to the invention include those described in U.S. Pat. No. 6,200,336 to Pavcnik et al. for a MULTIPLE-SIDED INTRALUMINAL MEDICAL DEVICE; U.S. application for patent Ser. No. 10/642,372 of Pavcnik et al. for an IMPLANTABLE VASCULAR DEVICE, filed on Aug. 15, 2003; and U.S. application for patent Ser. No. 10/828,716 of Case, et al. for an ARTIFICIAL VALVE PROSTHESIS WITH IMPROVED FLOW DYNAMICS, filed on Apr. 21, 2004; the entire disclosures of which are hereby incorporated into this disclosure for the purpose of describing suitable self-expandable intraluminal medical devices for use with delivery systems described herein.  
         [0030]     The groove  22  on the first inner surface  24  of the sheath member  12  is configured to engage the proximal flange  68  of the inner member  16 . The groove  22  is configured such that the inner member  16  can be advanced out of the first passageway  14  of the sheath member  12  until the proximal flange  68  of the inner member  16  engages the groove. Engagement of the proximal flange  68  with the groove  22  provides sufficient impedance to prevent the inner member  16  from exiting the passageway  14  of the sheath member  12  as the sheath member  12  is retracted.  
         [0031]     The groove  22  can be any suitable configuration that prevents the inner member  16  from exiting the passageway  14  of the sheath member  12  as the sheath member  12  is retracted. Suitable configurations of the groove  22  include, but are not limited to, a protrusion, a circumferential intermittent groove, or a continuous circumferential groove. The embodiment illustrated in  FIGS. 1 and 2  shows a continuous circumferential groove configuration. The proximal flange  68  is designed to fit into the groove  22  to prevent the inner member  16  from exiting the passageway  14  of the sheath member  12  as the sheath member  12  is retracted. To facilitate engagement of a recessed groove, the proximal flange  68  can be advantageously formed of a relatively rigid flexible material and can be slightly oversized with respect to the inner diameter of the first passageway  14 .  
         [0032]     The delivery system  10  can be operated in the following manner. First, the wireguide  46  is navigated through a body vessel  80  to the point of treatment  82  at which deployment of the self-expandable intraluminal medical device  28  is desired. Once the wireguide  46  is in an appropriate position, the delivery system  10  is navigated over the previously placed wireguide  46 .  
         [0033]     Once in proper position, the inner member  16  is deployed by proximally retracting the sheath member  12  to expose the inner member  16 . The fluid  20  is advantageously used to maintain the axial position of the inner member  16 . As the sheath member  12  is retracted the plunger  62  is depressed to transfer the fluid  20  from the reservoir unit  36  to the first passageway  14  of the sheath member  12 . The infusion of the fluid  20  into the sheath member  12  compensates for the increase in volume within the first passageway  14  of the sheath member  12  to provide additional fluid in proportion to the volume being added by retracting the sheath member  12  so that the fluid column neither advances nor retracts the inner member  16 .  
         [0034]     With the first passageway  14  of the sheath member filled by the fluid  20  to substantially prevent axial movement of the inner member  16 , the sheath member  12  is retracted. Retraction of the sheath member  12  is continued until the proximal flange  68  of the inner member  16  engages the groove  22  on the first inner surface  24  of the sheath member. Once this engagement has occurred, the mounting region  30  of the inner member  16  will be outside the delivery system  10 . At this point, the self-expandable intraluminal medical device  28  is fully deployed.  
         [0035]     Once the self-expandable intraluminal medical device  28  is fully deployed the inner member  16  can be retracted into the sheath member  12  by pulling back on the plunger  62 . In a luer fitting and syringe embodiment, the syringe would be withdrawn to pull the inner member  16  back into the sheath member  12 . In an embodiment that includes a removable reservoir unit  36 , the reservoir unit  36  could be removed and a means for applying a vacuum force, such as a syringe, tubing connected to a pump, a pump, and other suitable means, could be attached to the sheath member  12  to facilitate the retraction of the inner member  16 . Once the inner member  16  is retracted proximally into the sheath member  12 , the delivery system  10  can be retracted along the wire guide  30  and ultimately removed from the body vessel  80 , leaving the self-expandable intraluminal medical device  28  at the point of treatment  82 .  
         [0036]     Another exemplary embodiment of the invention (not illustrated) is similar to the embodiment illustrated in  FIGS. 1 and 2  except that the reservoir unit does not contain a plunger. The reservoir unit is advantageously designed and constructed such that a user could squeeze the reservoir unit to transfer the fluid into the sheath member to contact the inner member. Adequate one-way and two-way seals or valves within the system would ensure this embodiment functions similarly to the embodiment illustrated in  FIGS. 1 and 2 .  
         [0037]      FIG. 3  illustrates a delivery system  110  according to a second exemplary embodiment. The delivery system  110  according to this embodiment is similar to the delivery system illustrated in  FIGS. 1 and 2  except as described below.  
         [0038]     Delivery system  110  comprises a sheath member  112  defining a first passageway  114 , a proximal tubular member  136 , an inner member  116  slidably disposed within a distal cavity  118  of the first passageway  114  of the sheath member  112 , a pusher  128  that substantially prevents movement of the inner member  116  within the distal cavity  118  of the sheath member  112 , and a groove  122  on a first inner surface  124  of the sheath member. A self-expandable intraluminal medical device  128  is disposed on a mounting region  130  of the inner member  116 , as best illustrated in  FIG. 3 .  
         [0039]     As illustrated in  FIG. 3 , the proximal tubular member  136  is located at a first proximal end  132  of the sheath member  112 . The proximal tubular member  136  comprises a second proximal end  158 , a second distal end  160 , and a second passageway  164  defined by the second proximal  158  and distal  160  ends. The proximal tubular member  126  may be may be integrally formed with the sheath member  112  or formed separately and attached. The embodiment illustrated in  FIG. 3  shows a proximal tubular member  126  formed separately from and attached to the sheath member  112 .  
         [0040]     The pusher  120  is slidably disposed within the proximal tubular member  136  and the sheath member  112 . The pusher  120  comprises a third proximal end  172 , a third distal end  174 , and a distal flange  150 , and a proximal handle  162 . The pusher  120  is moved and positioned using the proximal handle  162 . The pusher  120  is moved into a position such that the distal flange  150  abuts a proximal flange  168  of the inner member  116 . The pusher  120  substantially prevents axial movement of the inner member  116  within the distal cavity  118  of the sheath member  112 . The second proximal end  158  of the proximal tubular member  136  may be advantageously designed to interact with the pusher  118  so that it does not move during retraction of the sheath member  112 . The second proximal end  158  of the proximal tubular member  136  may involve a snap, screw, velcro, or adhesive to prevent axial movement of the pusher  120 . The pusher  120  is advantageously formed of a relatively stiff material, such as a wire rod or hardened plastic. Also, hardened plastic including a wire core could be used.  
         [0041]     The distal flange  150  of the pusher  120  is adapted to allow a portion of a wireguide  146  to pass the pusher  120  to exit the delivery system  110  through an exchange port  142 . The distal flange  150  could be a semi-circular configuration as illustrated in  FIG. 3 , comprise an angled or indented portion, or any other suitable configuration that allows a portion of a wireguide  146  to pass the pusher  120  to exit the delivery system  110  through the exchange port  142 .  
         [0042]     The delivery system  110  can be operated in the following manner. First, the wireguide  146  is navigated through a body vessel to a point of treatment at which deployment of the self-expandable intraluminal medical device  128  is desired. Once the wireguide  146  is in an appropriate position, the delivery system  110  is navigated over the previously placed wireguide  146 .  
         [0043]     The pusher  120  is then moved into position using the proximal handle  162  such that the distal flange  150  abuts the proximal flange  168  of the inner member  116 . The pusher  120  advantageously maintains the axial position of the inner member  116  during retraction. With the pusher  120  in position to substantially prevent axial movement of the inner member  116 , the sheath member  112  is retracted. Retraction of the sheath member  112  is continued until the proximal flange  68  of the inner member  116  engages the surface groove  22  on the inner first surface  24  of the sheath member. Once this engagement has occurred, the mounting region  130  of the inner member  116  will be outside the delivery system  110 . At this point, the self-expandable intraluminal medical device  28  is fully deployed.  
         [0044]     Once the self-expandable intraluminal medical device  128  is fully deployed the inner member  116  can be retracted into the sheath member  112 . Removal of the inner member  116  can be accomplished by removing the pusher  120  and attaching a vacuum to the delivery system  110  or the pusher  120  could be advantageously designed to connect with the proximal flange  168  of the inner member  116  and the pusher  120  pulled back to withdraw the inner member  116  into the sheath member  112 . Once the inner member  116  is retracted back into the sheath member  112 , the delivery system  110  can be retracted along the wire guide  146  and ultimately removed from the body vessel, leaving the self-expandable intraluminal medical device  128  at the point of treatment.  
         [0045]     The foregoing disclosure includes the best mode of the inventor for practicing the invention. It is apparent, however, that those skilled in the relevant art will recognize variations of the invention that are not described herein. While the invention is defined by the appended claims, the invention is not limited to the literal meaning of the claims. Rather, it is expressly contemplated that the invention encompasses these and all other variations permitted by relevant law.