Abstract:
A method and device includes advancing a first stent and a second stent into a stenosed region of a blood vessel to protect or shield the vessel from possible blockage. The delivery device may include placement rings, selectively engagable by positioning members disposed on the outer wall of in inner catheter. The positioning members and the placement rings may be utilized to accurately place multiple stents within an afflicted vessel, in a single invasive procedure.

Description:
BACKGROUND 
       [0001]    The present invention relates generally to devices, methods and systems for vascular treatment. One embodiment of the device includes a sequential implant delivery system using a plurality of placement rings to place sequential self-expanding stents and embolic protection devices within a vessel wall. 
         [0002]    Vascular diseases and disorders are widespread health problems affecting many people. There are many chronic and acute diseases and disorders relating to the vascular system including, for example, thrombosis, embolism, aneurysm, atherosclerosis, arterioscholerosis, infarction and still others. 
         [0003]    Heart attacks and strokes are leading health concerns. Obstruction of blood flow and/or vessel rupture may cause inadequate blood supply to the heart, brain, and other parts or all of the body. Occlusive diseases involving constriction, narrowing or obstruction of a blood vessel often present serious, possibly life-threatening risks. Additionally, complications in vascular treatment(s) may themselves necessitate further treatment. Some such risks include formation of emboli, vessel damage, thrombogenesis, blood loss, hemorrhage, and others. Furthermore, trauma and other injuries may damage the vascular system and often require repair or replacement. 
         [0004]    At present, treatment of vascular disease, damage and disorders suffers from limitations, drawbacks and risks. The invention provides unique treatments and solutions to treatment of the foregoing and other problems. 
       BRIEF SUMMARY 
       [0005]    The endovascular device described below may overcome the aforementioned problems and relates to a medical device, and more particularly, to a sequential implant delivery device that allows the practitioner to utilize more than one self-expanding stent at a time. 
         [0006]    One embodiment includes a method for using a sequential delivery device, comprising introducing a device into an organ, the device including an inner catheter, a first stent, at least a second stent, a placement ring, and an outer sheath. The first stent includes a proximal end, a distal end, an exterior surface, and an inner lumen. The second stent includes a proximal end, a distal end, an exterior surface, and an inner lumen. The placement ring may be disposed between the proximal end of the first stent and the distal end of the second stent and the inner catheter includes a plurality of positioning members disposed axially along a longitudinal axis of the inner catheter. The method further includes disposing the device within a specified region of the organ, the distal end of the second stent being positioned approximately adjacent the proximal end of the first stent and unsheathing the first stent within said organ. The method further includes advancing the second stent through the organ and unsheathing the second stent. 
         [0007]    The method described above wherein the specified region of the organ is a blood vessel afflicted with a stenosis. 
         [0008]    The method described above wherein the first stent is a self expanding stent, and wherein the first stent expands when the outer sheath is withdrawn toward the proximal end of the blood vessel to expose the first stent. 
         [0009]    The method described above wherein the second stent is a self expanding stent, and wherein the second stent is at least partially expanded upon withdrawal of the outer sheath. 
         [0010]    The method described above wherein the second stent is a self expanding stent, the second stent being at least partially expanded upon withdraw of the outer sheath, and wherein the method further includes post-dilating the second stent with an inflation device. 
         [0011]    The method described above wherein the inflation device is a balloon catheter. 
         [0012]    The method described above wherein the positioning members are integrally formed along the longitudinal axis of the inner catheter. 
         [0013]    The method described above wherein the positioning members comprise a plurality of flanges, protruding from an exterior surface of the inner catheter in a distal direction, at an angle less than 90 degrees. 
         [0014]    The method described above wherein the positioning members comprise a plurality of barbs, protruding from an exterior surface of the inner catheter in a distal direction, at an angle less than 90 degrees. 
         [0015]    The method described above wherein the positioning members comprise a locking member protruding in a vertical plane, and wherein the placement ring comprises a receiving cavity in the vertical plane, wherein the receiving cavities correspond with the locking members. 
         [0016]    The method described above wherein the step of positioning said device within the vessel further comprises positioning the locking members out of alignment with respect to the receiving cavities and advancing the inner catheter and the placement rings along the longitudinal axis. 
         [0017]    Another embodiment includes a sequential implant delivery device, including an inner catheter, a first stent, a second stent, at least one placement rings, and an outer sheath. The inner catheter includes a plurality of positioning members disposed axially along a longitudinal axis of the inner catheter. The first stent includes a proximal end, a distal end, an exterior surface, and an interior lumen and the second stent includes a proximal end, a distal end, an exterior surface, and an interior lumen. The placement ring is disposed between the distal end of the second stent and the proximal end of the first stent and the placement rings, the first stent, and the second stent are selectively movable along a longitudinal axis of the inner catheter. 
         [0018]    The device described above wherein the positioning members selectively engage the placement rings. 
         [0019]    The device described above wherein the positioning members engage the placement rings when the inner catheter is advanced in a distal direction. 
         [0020]    The device described above wherein the positioning members are defined by a plurality of flanges, spaced along the longitudinal axis of the inner catheter. 
         [0021]    The device described above wherein the flanges protrude from an exterior surface of the inner catheter in a distal direction, at an angle less than 90 degrees. 
         [0022]    The device described above wherein the positioning members comprise a plurality of barbs, protruding from an exterior surface of the inner catheter in a distal direction, at an angle less than 90 degrees. 
         [0023]    The device described above wherein the positioning members comprise a locking member protruding in a vertical plane, and wherein the placement ring comprises a receiving cavity in the vertical plane, wherein the receiving cavities correspond with the locking members. 
         [0024]    The device described above wherein the locking members are rotatable to be unaligned with the receiving cavities, thereby enabling the inner catheter and the placement rings to be advanced along the longitudinal axis. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a side view of one example of a delivery device of the present invention; 
           [0026]      FIG. 2  is an inner catheter of the present invention; 
           [0027]      FIG. 3  is a side view of one example of an inner catheter and placement members of the present invention; 
           [0028]      FIG. 4  is a side view of one example of an inner catheter and placement members of the present invention; 
           [0029]      FIG. 5  is a side view of one example of an inner catheter and placement members of the present invention; 
           [0030]      FIG. 6  is a cross section of the inner catheter and placement rings, as shown in  FIG. 4 ; 
           [0031]      FIG. 7   a  is a side view of a stent assembly advanced through a stenosed region of a blood vessel in an initial position; 
           [0032]      FIG. 7   b  is a side view of a stent assembly advanced through a stenosed region of a blood vessel in a second position; 
           [0033]      FIG. 7   c  is a side view of a stent assembly advanced through a stenosed region of a blood vessel in a third position; 
           [0034]      FIG. 7   d  is a side view of a stent assembly advanced through a stenosed region of a blood vessel in a fourth position; and 
           [0035]      FIG. 8  is a front perspective view of an inner catheter of the present invention. 
           [0036]      FIG. 9  is a front perspective view of a delivery device of the present invention. 
           [0037]      FIG. 10  is a front perspective view of a delivery device of the present invention. 
           [0038]      FIG. 11  is a front perspective view of a delivery device of the present invention. 
           [0039]      FIG. 12  is a front perspective view of a delivery device of the present invention. 
           [0040]      FIG. 13  is a front perspective view of a delivery device of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0041]    An example of a sequential delivery device and method for protecting and reinforcing blood vessels afflicted with stenosis is shown in  FIGS. 1-7   d . The device and method may include the use of at least two structural stents, delivered to a vessel in the same delivery system or similar device. In order to properly place the aforementioned stents, it may be necessary to utilize a method of maneuvering the respective stents independently of one another. 
         [0042]    One example of a sequential delivery device is described below, but it should be understood that any sequential delivery device may be used with the inner catheter and placement rings described herein. Referring now to  FIG. 1 , one example of a sequential implant delivery device  10  may include a ratcheting-type inner catheter  12 , an outer sheath  14 , a first stent  16 , a secondary stent  18 , and at least one free floating placement device or ring  20 . 
         [0043]    In one embodiment, the first stent  16  and the secondary stent  18  are loaded into the delivery device  10  over the inner catheter  12  in a compressed condition. Generally, the stents may be loaded into the delivery device  10  from the device&#39;s proximal end  22 . However, the stents could be loaded into the delivery device  10  from either end using known techniques. 
         [0044]    As shown in  FIG. 1 , after the first stent  16  is loaded into the delivery device  10  and positioned toward the distal end  24  of the device  10 , the secondary stent  18  may also be loaded into the device  10 , behind the first stent  12 . The second stent  18 , like the first stent  16 , may generally be a self expandable vascular stent. However, the second stent  18  could also be a balloon expandable vascular stent, or any other suitable device. 
         [0045]    Generally, the outer sheath  14  of the delivery device  10  covers the secondary stent  18 , the first stent  16 , and the inner catheter  12 , preventing premature expansion of the stents. 
         [0046]    Referring now to  FIGS. 1 and 2 , the inner catheter  12  may include features, such as a plurality of spaced apart flanges  26  that extend upwardly, in the distal direction and allow the catheter to function in a ratcheting manner. The flanges  26  may be pre-formed in the inner catheter body  12 , or may otherwise be cut from or attached to an existing inner catheter tube  12 . In practice the flanges  26  will form an angle α with the wall of the inner catheter  12  which is preferably less than 90 degrees. 
         [0047]    Placement members or rings  20  may be disposed between or just distally of the respective flanges  26 . In one embodiment, at least one of the rings  20  is free floating in the delivery device. The term “floating” will be used herein to describe a placement ring that is not permanently affixed to any part of the delivery system. 
         [0048]    In one embodiment, and referring to  FIG. 1 , when the inner catheter  12  is pulled in the direction of arrow A, the flanges  26  may flatten against the outer wall of the inner catheter  12 , allowing the placement rings  20  and the stents  16 ,  18  to slide along the longitudinal axis of the inner catheter  12  without engaging the flanges  26 . If, however the inner catheter  12  is pushed in the direction of arrow B, the flanges  26  may engage the placement rings  20 , advancing both the rings  20  and the corresponding stent  16 ,  18  through the delivery device  10  and out of the outer sheath  14 , allowing a self-expanding stent  16 ,  18  to deploy in the blood vessel. Alternatively, the outer sheath  14  may be withdrawn along the direction of arrow A with respect to the inner catheter  12 , which will have the same effect as pushing the inner catheter in the direction of arrow B. These methods are described more fully below in connection with  FIGS. 7   a - d , below. 
         [0049]      FIGS. 3 and 4  show alternative embodiments of an inner catheter  12 . The embodiments shown in  FIGS. 3 and 4  may be used similarly to that of  FIG. 2 . As shown in  FIG. 3 , the inner catheter  12  may include a plurality of barbs  28 , formed or cut in the wall of the catheter  12 . These barbs  28  may engage corresponding notches  30  formed in the proximal ends of the placement rings  20 , selectively advancing the placement rings  20  through the delivery system  10  when the inner catheter  12  is advanced further into the vessel. 
         [0050]    Similarly, in  FIG. 4 , the inner catheter  12  may include a plurality of flanges  26 , as described in connection with the embodiment shown in  FIGS. 1 and 2 . It is contemplated that the flanges  26  may be spaced along the longitudinal axis of the inner catheter  12  in a variety of embodiments and placements, along either a vertical or horizontal plane, or both. 
         [0051]    Referring now to  FIGS. 5 and 6 , one embodiment of a delivery device may include an inner catheter  12  that employs a quarter-turn feature that selectively engages rotationally dependent placement ring(s)  34  based upon the catheter&#39;s  12  rotational alignment. As shown in  FIG. 5 , the catheter  12  may include at least one, and desirably two locking members  32 , that protrude from the outer surface of the catheter  12 . The locking members  32  may be positioned on opposite surfaces of the generally round catheter device  12 . 
         [0052]    Referring now to  FIG. 6 , the inner surface  36  of the rotationally dependent placement rings  34  may be formed to fit and move past the shape of the locking member  32  on the inner catheter  12  when the locking member  32  and the rotationally dependent placement ring  34  are similarly aligned. 
         [0053]    The respective placement ring  34  may be designed to have corresponding receiving cavities  38  within its inner surface, on opposite surfaces of the ring  34 . When both the locking member(s)  32  and the rings  34  are similarly aligned, as shown in  FIG. 6 , the ring  34  will slide past the locking member  32 . 
         [0054]    Referring now to  FIGS. 7   a - d , a delivery device may be used to effectively launch multiple stent devices within the blood vessel of a patient. Referring to  FIG. 7   a , the inner catheter  12  may also include a tip  40 . The tip  40  retains the placement rings  20  on the inner catheter  12  after they have been used to deploy a stent. In other words, the tip  40  keeps the rings  20  from sliding off the distal end of the inner catheter  12  and becoming emboli within the blood vessel. Secondly, the tip  40  provides a smooth, step-free transition between the outer sheath  14  and the inner catheter  12  during introduction. 
         [0055]    The tip  40  could be a flexible tip, a guiding tip, a cannula or another tip or tips of differing size, shape, and structure. The tip  40  may generally be made of a soft material, such as polyurethane, and may be attached only to the inner catheter  12 . 
         [0056]    With reference to  FIG. 7   a , there is shown an illustrative view of a delivery system  10  disposed within a blood vessel  42  and effectively placed at the initial position of deployment. A guidewire  44  may be positioned within the organ to be treated with its distal end advanced through and past the distal end of the region to be treated. Generally, the guidewire  44  may be as small as 0.014 inches in diameter. 
         [0057]    Once the guidewire  44  is positioned within the vessel  42 , the delivery device  10 , including the inner catheter  12 , the outer sheath  14 , the first stent  16 , the secondary stent  18  and the placement rings  20 , is threaded over the guidewire  44 . The tip  40  of the inner catheter  12 , as well as the distal end of the outer sheath  14 , may include a radiopaque marker used for positioning purposes. In this manner, the tip  40  of the inner catheter  12  can be positioned distally of the region to be treated. The first stent  16  and the secondary stent  18  may also include radiopaque markers at either end. The markers may be in the form of gold rivets on the terminating eyelets of the stent bodies. 
         [0058]    The proximal end of the delivery device  10 , including the outer sheath  14  and the inner catheter  12 , may be attached to handles. The handles are generally located outside of the patient&#39;s body and allow the sheath  14  and the inner catheter  12  to be moved independently of, or relative to, one another. The handles may include a hub  46  attached to the proximal end of the outer sheath  14 , allowing the user to withdraw the outer sheath  14  in the direction of arrow A. In addition, the inner catheter  12  may be attached to an inner shaft, control rod, push rod, or the like  48  and may be disposed through the hub  46 . The user may be able to hold the inner catheter  12  in place, while the hub  46  pulls the outer sheath  12  in the direction of arrow A. Alternatively, the inner catheter  12  may be moved in the direction of arrow B by moving the inner catheter  12  in and out of the hub  46 , holding the control rod  48  for support. 
         [0059]    In  FIG. 7   a  the loaded delivery device  10  has been moved into the deployment or initial position. Once the loaded delivery device  10  is in place, using the handles the user may begin to withdraw the outer sheath  14  relative to the first stent  16  and the secondary stent  18 , in the direction of arrow A. Other deployment techniques and devices are also contemplated. 
         [0060]    As shown in  FIG. 7   b , once the outer sheath  14  has been withdrawn in the direction of arrow A to a secondary position, the first stent  16  will deploy into the vessel. The first stent  16  and the secondary stent  18  will be prevented from moving proximally, the same direction of the outer sheath  14 , by the placement rings  20  disposed within the delivery system  10 . The placement rings  20  desirably float freely within the delivery device  10  and are themselves impeded from proximal movement by the flanges  26  disposed on the inner catheter  12 . 
         [0061]    In this embodiment the placement members  20  are rings that extend around the body of the inner catheter. This configuration allows the members  20  to support each surface of the individual stents, in order to prevent deformation. The placement rings may be the translational interface between the intermittent barbs of the inner catheter, and the proximal face of a given stent. The end faces/surfaces of the stents are not uniform, and therefore require the continuous and un-interrupted face of the placement ring bearing against it to distribute the force evenly through as many points of contact as possible. 
         [0062]    Alternatively, it is contemplated that the placement members may be replaced by a ring of, or multiple individual, flanges placed around or formed into the body of the inner catheter, as shown in  FIG. 8 . Multiple or continuous flanges may support the end faces of the stents much like a placement ring. 
         [0063]    As shown in  FIG. 7   c , the inner catheter  12  may then be withdrawn in the direction of arrow A, while the outer sheath  14  is stationary. The inner catheter  12  may be withdrawn so that the tip  40  is adjacent the distal placement ring  20 . The placement rings  20  and the secondary stent  18  remain in place while the flanges  26  on the inner catheter  12  are compressed distally and both the inner catheter  12  and compressed flanges  26  are moved proximally through the center lumen of the rings  20  and the stent  18 . The inner catheter  12  may be moved a measured distance in order to dispose the distal flange  26   a  behind the proximal placement ring  20   b.    
         [0064]    Once the tip  40  has been withdrawn into the third position, the secondary stent  18  may then be advanced distally over the inner catheter  12  by pushing flange  26 , the positioning ring  20  and the stent through the vessel. The secondary stent may be disposed within the vessel so that when deployed, the distal end of the secondary stent  18  overlaps with the proximal end of the first stent  16 . This is only one example of stent placement within the vessel, but many others are contemplated using the method described above. 
         [0065]    Referring now to  FIG. 7   d , the there is illustrated deployment of the second stent  18 . Once the secondary stent  18  has been advanced through the vessel  42 , the outer sheath  14  may again be withdrawn in the direction of arrow A, thus exposing the secondary stent  18  to the inner surface of the vessel  42 . Again, the self expanding secondary stent  18  expands as it exits the sheath  14 . The delivery device, including the outer sheath  14  and inner catheter  12 , may then be removed from the patient&#39;s body. 
         [0066]    Alternative embodiments of the delivery system include using a tertiary catheter  50 , secured to the most proximal placement ring  20   a . As shown in  FIG. 9 , the proximal ring  20   a  would be secured to a tertiary catheter  50  such that the inner catheter  12  moves independently of the proximal placement ring  20   a . This allows the floating distal ring  20   b  to ratchet forward as the inner catheter  12  is moved proximally. 
         [0067]    Another embodiment may be the use of a delivery device that includes an inner catheter  12  and an outer sheath, both having flanges placed on the outer and inner surfaces, respectively. As shown in  FIG. 10 , the outer sheath  14  may also include flanges  52  similar to that of the inner catheter  12  but on the inside surface. This configuration prevents the floating rings  20  from moving in the proximal direction when the inner catheter  12  is pulled in the proximal direction. 
         [0068]    Another embodiment of the delivery device includes a dual diameter outer sheath  14 . Referring now to  FIG. 11 , the outer sheath  14  may be formed using a stepped mandril providing an impingement surface  54  for the proximal ring  20   b . The proximal ring  20   b  will thereby remain stationary during proximal movement of the inner catheter  12 . 
         [0069]    Yet another embodiment of the delivery device includes a uni-direction placement ring  56 , in addition to the floating ring  20 . As shown in  FIG. 12 , the proximal ring  56  may be shaped in such a way that the ring  56  and the outer sheath  14  can only move in one direction with respect to each other another. 
         [0070]    Finally, it is contemplated that the floating placement rings  120  may be utilized in a delivery device  100  with or without the ratcheting-type inner catheter  12 . Assembly of a delivery system  100  with such a floating ring  120  can be achieved by ensuring that the inner diameter of the ring  120  is less than the outer diameter of the attached tip  140 . As shown in  FIG. 13 , multiple stents,  116  and  118 , may be loaded in to the delivery device  100 , over the inner catheter  112 , with floating rings  120  between each of the stents. At the very proximal end of the device  100 , at least one ring  122  may be affixed to the inner catheter  112 . 
         [0071]    It is intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.