Abstract:
A delivery system ( 10 ) for implanting a medical device ( 30 ) such as a venous valve into the vasculature of a patient. The delivery system includes a delivery catheter ( 11 ) having a device-containing portion ( 15 ) adjacent to the distal end ( 14 ) thereof, and an inner member ( 16 ) extending through the catheter and beyond the distal end thereof, to an atraumatic distal tip portion ( 17 ) forward of the catheter distal end. The inner member extends through the medical device in the device-containing region, includes a proximal portion ( 18 ) with a sufficiently large diameter to prevent longitudinal movement of the device as the catheter is retracted during deployment, and centers the device upon release from the distal catheter end during deployment. The inner member is preferably radiolucent underlying the device for contrast with radiopaque markers ( 43 ) of the device. The inner member preferably includes a flat portion ( 35 ) extending from the device-containing portion to the proximal end ( 22 ) to form a passageway or lumen ( 21 ) with the delivery catheter to transmit hydrating fluid to a device such as a valve containing lyophilized tissue requiring hydration immediately prior to patient implantation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority of provisional application Serial No. 60/338,714, filed Nov. 29, 2001. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to medical devices and in particular to a delivery system for delivering a medical device to a selected site.  
         BACKGROUND OF THE INVENTION  
         [0003]    Delivery systems have been known for many years, for use with the Seldinger technique and related percutaneous entry techniques for vascular delivery of implants into the vasculature of human or veterinary patients. Such systems typically utilize a wire guide inserted into the vasculature to extend to the site of implantation of a medical device such as a stent, stent graft, filter, occluder, valve or the like. An introducer sheath is placed over a portion of the guide wire, and a catheter inserted over the guide wire within the introducer sheath and beyond its distal tip, with the implant contained within a distal portion of the catheter until the implant is delivered to the site of implantation. The implant is then released from the catheter distal tip and deployed. The insertion and progress of the procedure are monitored closely through fluoroscopy, angiograms or CT scanning or the like, in which radiopaque markers are commonly used as landmarks on the wire guide, catheter and implantable device to assure eventual accurate positioning of the device at the site of implantation and its full deployment.  
           [0004]    One delivery system is known from U.S. Pat. No. 4,494,531 for delivery of a vena cava filter into the vena cava of the vasculature. The system includes a wire guide with a handle, and a cartridge catheter contains the filter at its distal end in a reduced diameter confinement and having a rear assembly. Once access is gained to the vasculature by an introducer sheath and a dilator, and the dilator is removed from the sheath, the cartridge catheter is inserted through the sheath until its distal end reaches the deployment site, whereafter the collapsed filter is deployed by gradually retracting the catheters distal end, while the filter is held axially fixed by a positioning wire guide extending to the proximal end of the filter, to initially expose the distal end of the filter having outwardly curving struts with barbs. The exposed filter then expands so that its distal barbs engage and seat in the vessel wall in cooperation with sharp, forward jabs or manipulation of the catheter, and then the remainder of the filter forms a “bird&#39;s nest” and its proximal barbs engage and seat in the vessel wall to anchor the filter in position as the catheter continues to be retracted. The particular filter disclosed in the patent is sold by Cook Incorporated, Bloomington, Ind. as the Gianturco-Roehm BIRD&#39;S NEST Vena Cava Filter.  
           [0005]    Delivery systems for filters are also disclosed in U.S. Pat. Nos. 5,329,942 and 5,324,304, wherein the filter is released at the deployment site by retraction of the catheter distal end from therearound as the proximal filter end is held in place axially.  
           [0006]    It is desired to provide a delivery system for medical devices such as vascular valves that provides for assuredly centering the distal ends of valves during deployment from the delivery catheter.  
           [0007]    It is also desired to provide such a medical device delivery system that does not interfere with precise visualization of radiopaque markers on the medical device such as a vascular valve being implanted.  
           [0008]    It is further desired to provide such a delivery system to have a minimized diameter for use with medical devices such as vascular valves containing lyophilized tissue that enables hydration of the lyophilized tissue at the time of delivery into the patient.  
         SUMMARY OF THE INVENTION  
         [0009]    The foregoing problems are solved and a technological advance is achieved by an illustrative embodiment of a medical device delivery system of the present invention. The delivery system includes a delivery catheter having a device-containing region such as, for example, a vascular valve-containing region adjacent to its distal tip, and an inner member within the delivery catheter and movable relatively axially with respect thereto when inserted over a wire guide that is positioned in the vasculature of a patient. The inner member has a reduced diameter portion extending through the device or valve-containing region to a distal tip portion distally of the device or valve-containing region, with the distal tip portion having a maximum diameter approximately the catheter diameter at the distal end thereof. The delivery system of the present invention is particularly useful with valves providing clearance for the inner member to extend through the valve opening when the valve is in a compressed state within the device or valve-containing region of the delivery catheter.  
           [0010]    The distal end of the inner member extends sufficiently forward of the catheter distal end and the valve to engage the vessel distally of the deployment site, and in cooperation with the nearer proximal portions of the catheter centered within adjacent portions of the vasculature thus tending to center the distal end of the delivery catheter advantageously during valve deployment and also tending to temporarily straighten somewhat the local vessel anatomy. The compressed valve is movable with the inner member relatively axially with respect to the delivery catheter distal end upon actuation of the deployment procedure. The distal end of the valve sufficiently engages the inner member when being released from the distal end of the delivery catheter during catheter retraction to generally remain centered in the vessel and generally aligned parallel to the vessel at the deployment site. Preferably, the distal tip portion of the inner member is tapered on both its distal and proximal ends, and is advantageously atraumatic during insertion into the patient, and nonsnagging and nondisruptive as the inner member is withdrawn proximally through the valve following expansion and deployment thereof.  
           [0011]    In another aspect, the inner member includes a small diameter radiolucent or transparent region coinciding with the valve in the device or valve-containing region such that radiopaque markers on the device or valve are easily distinguishable under fluoroscopy during positioning and deployment, as the device or valve is movable with the inner member during positioning and during deployment when the delivery catheter is retracted to expose the device or valve.  
           [0012]    In a third aspect, the delivery system of the present invention is especially useful with devices or valves having lyophilized materials that require hydration before deployment. The inner member proximally of the device or valve-containing region is cylindrical in cross-section but containing a flattened side extending from the valve-containing region to the proximal end of the delivery system. Thus, a passageway or lumen is formed between the delivery catheter and inner member for advantageously irrigating and/or hydrating the lyophilized material. Hydration fluid such as water or saline solution is injectable into the delivery system through an injection port such as by use of a syringe, and the fluid is transmitted through the delivery catheter within the region between the flattened side of the inner member and the inner surface of the catheter wall, to reach the compressed valve in the device or valve-containing region for hydration of the lyophilized tissue. Such hydration is to be performed immediately prior to the insertion of the delivery system into the patient for placement of the valve. Alternatively, the proximal portion of the inner member can have a diameter less than the inner diameter of the delivery catheter to form a passageway or lumen significantly greater in cross-sectional area than the lumen formed by the portion of the flat inner member and the delivery catheter. As a result, greater volumes of irrigation fluid can be delivered to the contained medical device. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0013]    Embodiments of the delivery system of the present invention will now be described by way of example with reference to the accompanying drawings, in which:  
         [0014]    [0014]FIG. 1 depicts a top view of an illustrative preferred embodiment of the medical device delivery system of the present invention;  
         [0015]    [0015]FIG. 2 depicts an exploded and enlarged view of the delivery catheter and the inner member of the delivery system of FIG. 1;  
         [0016]    [0016]FIG. 3 depicts an enlarged and longitudinally sectioned view of the inner member and the delivery catheter of the delivery system of FIG. 2;  
         [0017]    [0017]FIG. 3A depicts an enlarged and longitudinally sectioned view of an alternative embodiment of the distal tip portion of the inner member of the delivery system of FIG. 2;  
         [0018]    [0018]FIG. 4 depicts an enlarged partial and longitudinally sectioned view of the inner member inserted through the delivery catheter of the delivery system of FIG. 3 with a medical device contained therein;  
         [0019]    [0019]FIG. 4A depicts an enlarged partial and longitudinally sectioned view of an alternative embodiment of the delivery catheter of the delivery system of FIG. 3 with an inner member positioned therethrough;  
         [0020]    [0020]FIG. 5 depicts an enlarged and partially sectioned side view of the Y-adaptor or connector of the medical device delivery system of FIG. 1;  
         [0021]    [0021]FIGS. 6 and 7 depict an alternative embodiment of the Y-adaptor or connector of the delivery system of FIG. 5;  
         [0022]    [0022]FIG. 8 depicts an alternative embodiment of the inner member of the delivery system of FIG. 1, which can be used in combination with the Y-adaptor embodiment of FIGS. 6 and 7;  
         [0023]    [0023]FIG. 9 is a cross-sectional view of the cylindrical ring of the intermediate portion  19  of FIG. 8 taken along the line  9 - 9 ;  
         [0024]    [0024]FIG. 10 depicts another illustrative embodiment of the positioning arrangement of the delivery system of FIG. 8;  
         [0025]    [0025]FIGS. 11 and 12 depict top and side views of still another illustrative embodiment of a positioning member of the delivery system of FIG. 1 in which the distal end of the outer tube is shaped to engage the proximal end of a stent valve medical device;  
         [0026]    [0026]FIGS. 13 and 14 depict top and side views of another illustrative embodiment of the distal tip portion of the inner member of the delivery system of FIG. 1;  
         [0027]    [0027]FIGS. 15 and 16 depict top and side views of still yet another embodiment of the inner member of the delivery system of FIG. 1;  
         [0028]    [0028]FIG. 17 depicts a pictorial view of still yet another embodiment of the inner member of the delivery system of FIG. 1;  
         [0029]    [0029]FIG. 18 depicts a pictorial view of yet still another embodiment of the inner member and, in particular, the distal tip portion of the inner member of the delivery system of FIG. 1; and  
         [0030]    [0030]FIGS. 19 and 20 depict pictorial and side views of a locking mechanism for fixing the relative position of the inner member and delivery catheter of the delivery system of FIG. 1 in which a check flow valve is utilized instead of a side arm. 
     
    
     DETAILED DESCRIPTION  
       [0031]    The present invention is especially useful with a valve stent of the type disclosed in U.S. patent application Ser. No. 09/777,091 filed Feb. 5, 2001. The stent valve disclosed therein comprising a “square” stent (as disclosed in U.S. Pat. No. 6,200,336) with extracellular matrix material such as small intestine submucosa (SIS) material secured thereto extending between the struts and having a valve opening or slit through the material. Such a valve stent is deliverable to the treatment site in the vasculature and is deployable without any specific control device within the delivery catheter and simply expands and self-seats in position in the vessel as the catheter distal end is retracted. The valve stent is simply held in position in the valve containing region distally of the larger diameter portion of the inner member immediately proximal thereto, thus overcoming any frictional forces by movement of the catheter inner surface as the catheter is retracted.  
         [0032]    [0032]FIG. 1 depicts a top view of an illustrative preferred embodiment of medical device delivery system  10  of the present invention. The delivery system includes delivery catheter  11  having inner lumen  12  through which inner member or dilator  16  is inserted therethrough. Well-known Luer-lock connecter hub  52  is affixed to the proximal end of the delivery catheter. Well-known Touhy-Borst Y-adaptor or connector  38  is connected to the connector hub of the delivery catheter through which inner member  16  is also inserted and extended therethrough. Threaded lock  53  at the proximal end of Y-connector  38  is rotated to fixedly position inner member  16  longitudinally with respect to the delivery catheter and the Y-connector. Side arm  40  of the Y-connector extends laterally at an acute angle proximally from main arm  39 . Alternatively, a commercially available Check-Flo valve can be connected to connector hub  52  as depicted in FIG. 20. This valve is available from Cook Inc., Bloomington, Ind. A fluid irrigation source (not shown) is connected to side arm  40  via well-known inner interconnecting tubing and valve  54 . The side arm of the Y-adaptor or connector permits the delivery of a fluid to hydrate lyophilized tissue of the medical device contained in device-containing region  15  of the delivery catheter adjacent the distal end thereof. The medical device that is contained in the delivery system of the present invention is typically delivered percutaneously to a vascular deployment site over a well-known wire guide that is inserted into the vascular system and to the deployment site. Inner lumen  24  extends longitudinally through inner member  16  as well as the delivery system, which is introduced over the wire guide through the inner lumen.  
         [0033]    [0033]FIG. 2 depicts an exploded and enlarged view of delivery catheter  11  and inner member  16  of delivery system  10  of FIG. 1. Inner member or dilator  16  is insertable through inner lumen  12  of delivery catheter  11  that extends longitudinally between proximal end  13  and distal end  14 . In particular, the inner member is also insertable through device-containing region  15  adjacent distal end  14 . Inner member  16  includes a distal tip portion  17 , proximal portion  18  and intermediate portion  19  disposed between the distal tip portion and the proximal portion. A medical device such as the aforementioned stent valve is positioned around the intermediate portion of the inner member. In this particular embodiment, the medical device is a stent valve including lyophilized tissue material that is affixed to a collapsible wire stent frame. The lyophilized tissue material has a slit therein through which the intermediate portion of the inner member is inserted therethrough and engages the tissue material when the stent valve is positioned around the intermediate portion. The stent valve is maintained in a compressed state or condition by delivery catheter  11  when the inner member and compressed valve are inserted therein. The assembled medical device delivery system  10  has inner member  16  extending through inner lumen  12  and beyond the distal end of delivery catheter  11 . The compressed medical device is contained in device-containing region  15  of the delivery catheter adjacent distal end  14  of the delivery catheter. The compressed stent valve is deployed at the desired vascular site by maintaining inner member  16  in a stationary position and withdrawing or pulling back the delivery catheter from the intermediate portion of the inner member.  
         [0034]    Proximal portion  18  of inner member  16  has a cylindrical outer surface  34  with a recessed or flat portion  35  extending longitudinally therealong and communicating with intermediate portion  19 . This recessed or flat portion of the inner member in combination with delivery catheter  11  forms a lumen through which to hydrate the stent valve contained in the intermediate portion of the inner member. An advantage of the present invention is that reduced diameter intermediate portion  19  of the inner member is inserted through and engages the medical device for centering the medical device in the vessel in which the device is being deployed. To maintain the longitudinal position of the medical device in the vessel during deployment, proximal portion  18  of the inner member includes a blunt distal end  20  to engage the proximal end of the medical device positioned in the intermediate portion  19 . This blunt distal end is also effective in holding, for example, just a stent that can be contained in device-containing region  15  and intermediate portion  19 . This is most effective when the blunt distal end closely approximates the size of inner lumen  12  of delivery catheter  11 .  
         [0035]    Distal tip portion  17  of inner member  16  includes tapered proximal end  31 , tapered distal end  32  and an intermediate segment  33  disposed between the tapered distal and proximal ends. The tapered distal end facilitates atraumatic placement of the delivery system to the deployment site. Tapered proximal end  31  advantageously provides atraumatic withdrawal of the inner member through the valve slit or opening after the stent valve has been deployed at the desired vessel site. Intermediate segment  33  approximates the size and shape of inner lumen  12  of delivery catheter  11  so as to provide an atraumatic transition between the assembled inner member and delivery catheter.  
         [0036]    [0036]FIG. 3 depicts an enlarged and longitudinally sectioned view of inner member  16  and delivery catheter  11  of delivery system  10  of FIG. 2. Inner member  16  of delivery system  10  includes inner tube  25  of a radiolucent material  26  such as, for example, well-known medical grade nylon  12  polyamide material. By way of example, inner tube  25  is approximately 77 cm in length with an outside diameter of approximately 0.059 inches, an inside diameter of approximately 0.040 inches, and a wall thickness of approximately 0.0095 inches. This inner tube extends almost the entire length of the inner member through proximal portions  18 , intermediate portion  19  and distal tip portion  17 . The translucent material of the inner tube through intermediate portion  19  of the inner member advantageously provides better fluoroscopic visualization of the stent valve contained therearound. The radiolucent material provides very little, if any, interference with the heavier density stent, stent valve material or radiopaque markers thereon.  
         [0037]    Inner member  16  also includes outer tube  27  coaxially positioned around inner tube  25 . For all practical purposes, outer tube  27  designates the proximal and distal ends of proximal portion  18  of the inner member. By way of example, outer tube  27  is approximately 70 cm in length with an outside diameter of approximately 0.117 inches, an inside diameter of approximately 0.062 inches, and a wall thickness of approximately 0.0275 inches of a radiopaque material  28  such as well-known nylon  12  polyamide material filled with a high density radiopaque filler material such as tungsten, barium, bismuth, and the like. Outer surface  34  of outer tube  27  includes a recessed or flat portion  35  which forms a fluid lumen with the delivery catheter to hydrate a medical device positioned around intermediate portion  19 . This recessed or flat portion  35  is skived into the outer surface of the outer tube approximately 0.012 inches. This recessed or flat portion extends from proximal end portion  18  of the inner member and outer tube and communicates with intermediate portion  19 . Proximal end  55  of the inner and outer tubes are, for example, thermally attached and flared in a well-known manner for connection to well-known Luer-lock connector hub  56  having threaded female and male parts  57  and  58 . Blunt distal end  20  of outer tube  27  is advantageously used to engage the proximal end of a medical device contained around intermediate portion  19 .  
         [0038]    Distal tip section  17  of inner member  16  includes tapered proximal end  31 , tapered distal end  32  and intermediate segment  33  disposed therebetween. By way of example, the distal tip section is preferably 4.5 cm in length with an outside diameter of approximately 0.117 inches, which is approximately the same as the outside diameter of outer tube  27 . The distal tip portion  17  can range in length from approximately 1.25 cm to 7 cm. By way of further example, tapered proximal end  31  can range in length from approximately 2.5 mm through 10.0 mm with a preferred length of approximately 5.0 mm. If the tapered proximal end is too short, there will be difficulty in retracting the distal tip portion through the valve orifice or slit. In addition, there can be possible induced migration of the valve along with possible damage to the valve itself. Should the tapered proximal end be too long, there is the possibility of wedging the valve between the distal tip portion and the delivery catheter. A taper that is too long may also lead to difficulties with deployment of the stent valve.  
         [0039]    Straight intermediate segment  33  can range from approximately 0.0 through 3.0 cm with a preferred length of approximately 2.0 cm. Should the straight intermediate segment be too short, elastic deformation of the distal tip portion during forward or reverse motion over a wire guide can lead to poor delivery catheter/inner member transition or the exposure of the valve chamber and valve. Should the straight intermediate segment  33  be too long, this can lead to difficulties with deployment.  
         [0040]    Tapered distal end  32  can range in length from approximately 1.0 through 3.0 cm with a preferred length of 2.0 cm. Should tapered distal end  32  be too short, there is the possibility of more trauma to the patient and less optimal performance and trackability of the delivery system. A tapered distal end that is too long can create production difficulties or lead to difficulties with device deployment. As depicted, the distal end of the inner tube  25  extends through tapered proximal end  31  and into straight intermediate segment  33 . By way of example, the diameter of the passageway through these segments is approximately 0.059 inches approximating the outside diameter of inner tube  25 . A well-known medical grade adhesive is applied to the outside surface of inner tube  25  about the distal end thereof to fixedly attach the distal end portion thereto. The remaining portion of the lumen extending through the distal tip portion is approximately 0.038 inches to accommodate a 0.38 inch wire guide. Distal tip portion  17  is formed from a well-known radiopaque nylon  12  polyamide material such as described for outer tube  27 .  
         [0041]    Delivery catheter  11  comprises, for example, a 9.0 French cylindrical tube of radiopaque fluorinated ethylene propylene (FEP) approximately 60 cm in length with an outside diameter of approximately 0.141 inches, an inside diameter of approximately 0.121 inches, and a wall thickness of approximately 0.010 inches. Luer-lock connector hub  52  comprises well-known threaded female and male connector parts  59  and  60 , which are affixidly attached to flared proximal end  13  of delivery catheter  11 . Device-containing region  15  of the delivery catheter is adjacent distal end  14  of the delivery catheter through which inner lumen  12  extends longitudinally therethrough.  
         [0042]    [0042]FIG. 3A depicts an enlarged and longitudinally sectioned view of an alternative embodiment of distal tip section  17  of inner member  16  of delivery system  10  of FIG. 3. Similar to FIG. 3, distal tip section  17  of this alternative embodiment includes a translucent inner tube  25  extending into the passageway of the distal tip section. However, distal tip section  17  of this alternative embodiment includes a radiopaque marker band  36  positioned at the proximal end of intermediate segment  33 . The distal end of the marker band is counterbored to engage a recessed flange at the proximal end of intermediate segment  33 . The marker band is disposed next to the intermediate segment over inner tube  25  and held in position with, for example, a medical-grade adhesive or glue such as a commercially available ultraviolet curable glue like Loctite 3311 glue. This glue can be shaped to form tapered proximal end  31 . Alternatively, tapered proximal end  31  can be made part of and/or formed with radiopaque marker band  36 . As a result, the radiopaque marker band is radiographically visualized so that delivery catheter  11  and distal tip portion  17  of inner member  16  can be visualized during the separation or joining thereof during the delivery process.  
         [0043]    [0043]FIG. 4 depicts an enlarged partial and longitudinally sectioned view of inner member  16  inserted through delivery catheter  11  of delivery system  10  of FIG. 3 with medical device  30  contained therein. The medical device such as the previously described stent valve is positioned around and engaging intermediate portion  19  of the inner member. The medical device is maintained in a compressed condition around the intermediate portion of the inner member by delivery catheter  11 , and in particular, device-containing region  15  adjacent distal end  14  of the delivery catheter. Distal end  14  of the delivery catheter is positioned around intermediate segment  33  of distal tip portion  17  of the inner member. The distal end of the delivery catheter is beveled to facilitate a smooth transition between intermediate segment  33  of the distal tip portion of the inner member. Tapered proximal end  31  of the distal tip portion of the inner member extends to intermediate portion  19  and provides for a smooth atraumatic withdrawal of the inner member through the slit or orifice of the stent valve medical device when deployed in a vessel.  
         [0044]    Proximal portion  18  of the inner member includes distal end  20  that is sized approximating the inner lumen of the delivery catheter at least through device-containing region  15 . The distal end of the proximal portion engages the proximal end of medical device  30  and maintains the medical device in a fixed longitudinal position during withdrawal of the delivery catheter during deployment of the medical device. As previously suggested, the outer surface of the proximal portion and outer tube  27  includes recessed portion  35  that cooperates with the delivery catheter to form irrigation lumen  21  for hydrating lyophilized tissue material  42  of stent valve medical device  30 . This irrigation lumen extends from the proximal end region of the inner member to intermediate portion  19 . As also previously suggested, medical device  30  includes wire frame stent  44  with lyophilized tissue material  42  attached thereto. Radiopaque markers  43  are positioned on the wire frame segments of the stent for fluoroscopic visualization of the stent valve during placement of the device in the vasculature of a patient. Intermediate portion  19  of inner member includes radiolucent material  26  to further improve the fluouroscopic visualization of the stent valve medical device. Inner lumen  24  extending longitudinally through the delivery device and, in particular, inner member  16  is used for guiding the delivery system over a well-known guide wire to the deployment site in the vascular system of the patient. Guide wire  50  extends through inner lumen  24 .  
         [0045]    [0045]FIG. 4A depicts an enlarged partial and longitudinally sectioned view of an alternative embodiment of delivery catheter  11  of delivery system  10  of FIG. 4 with inner member  16  inserted therein. Delivery catheter  11  comprises a cylindrical tube  37  of, for example, a radiopaque fluorinated ethylene propylene material with a device-containing region  15  of a cylindrical tube  83  of a clear or transparent non-radiopaque fluorinated ethylene propylene material thermally bonded to radiopaque tube  37  at the distal end thereof. The two tubes are thermally bonded at tapered bonding area  23 . The strength of the thermal bond is improved by tapering the one end of one tube and correspondingly beveling the matching end of the other tube. The transparent tube allows for visual inspection of the medical device such as a venous valve contained within region  15  of the delivery catheter and around the recessed portion of inner member  16 . In addition, the transparent tube  21  allows a check for migration, for example, of a medical device containing lyophilized small intestine submucosa which is used, for example, in a venous valve. Not only can hydration be verified through the transparent tube, but a visual check can also be made to verify the absence of air emboli in the catheter. In this alternative embodiment depicted in FIG. 4A, coaxial outer tube  27  has been reduced in its outer diameter by one French size so as to create an approximately 0.017 to 0.018 inch difference from that of the previously described embodiment. As a result, recessed or flat portion  35  is no longer needed since the outer tube is smaller in its outer diameter thus allowing for an irrigation or hydration lumen  41  to be created between inner member  16  and delivery catheter  11 .  
         [0046]    [0046]FIG. 5 depicts an enlarged and partially sectioned side view of Y-adaptor or connector  38  of medical device delivery system  10 . Distal connector  61  of the Y-adaptor is connected to Luer-lock connector hub  52  of the delivery catheter. Threaded lock  53  is positioned at the proximal end of the Y-adaptor for fixedly positioning inner member  16  longitudinally therein. The inner member extends through main arm  39  of the Y-adaptor and through the delivery catheter. The threaded parts of threaded lock  53  compress well-known flexible polymeric material seal  62  to engage and fixedly position the inner member. In addition, flexible polymeric material seal  62  also forms a hemostatic seal at the proximal end of main arm lumen  64  for preventing blood flow from the patient. Y-adaptor  38  also includes side arm  40  connected to interconnecting tubing and valve  54 . The side arm includes irrigation lumen  63  extending longitudinally therethrough and communicating with main arm lumen  64 . Inner member  16  is longitudinally positioned in main arm lumen  64  such that proximal end region  22  with recessed or flat portion  35  is in communication with side arm lumen  63 . The recessed portion of outer surface  34  of the inner member in combination with the inner lumen of the delivery catheter and Y-adaptor forms irrigation lumen  21  for hydrating the lyophilized tissue material of the stent valve medical device contained around the intermediate portion of the inner member.  
         [0047]    [0047]FIGS. 6 and 7 depict an alternative illustrative embodiment of Y-adaptor or connector  38  of delivery system  10  of FIG. 5. Here again, inner member  16  extends longitudinally through main arm lumen  64  as previously described with recessed or flat portion  35  in fluid communication with side arm lumen  63 . Flexible polymeric material seal  62  now takes on the form of an O ring to facilitate a hemostatic seal between the inner member and the Y-adaptor. At proximal end  65  of the Y-adaptor are apertures  66  and  67  extending transversely therethrough. A pair of transversely oriented, diametrically facing slots  68  are formed in inner member  16 , which align with apertures  66  and  67  of the Y-adaptor. Two prong key  69  is inserted through the apertures and slots for fixedly positioning the inner member relative to the Y-adaptor. This fixedly positions the inner member with respect to the Y-adaptor not only longitudinally but also circumferentially. This advantageously maintains the position of recessed or flat portion  35  of the inner member with respect to the side arm lumen of the Y-adaptor. In addition, this is also utilized in combination with other structures which will be described hereinafter to rotationally fix the position of the stent valve medical device contained at the distal end of the delivery catheter.  
         [0048]    [0048]FIG. 8 depicts an alternative illustrative embodiment of inner member  16  of delivery system  10  of FIG. 1, which can be used in combination with the Y-adaptor embodiment of FIGS. 6 and 7. Positioned around intermediate portion  19  and, in particular, inner tube  25  is a cylindrical ring  70  of a flexible atraumatic material such as silicone and the like. This cylindrical ring of flexible material is positioned near the center of the intermediate portion of the inner member so as to engage wire frame segments or members of the stent valve medical device contained in the delivery system.  
         [0049]    [0049]FIG. 9 depicts a cross-sectional view of cylindrical ring  70  of intermediate portion  19  of FIG. 8 taken along the line  9 - 9  containing wire frame members  71  in delivery catheter  11 . As depicted, cylindrical ring  70  is circumferentially positioned around inner tube  25  with delivery catheter  11  surrounding cylindrical ring  70  and wire frame members  71  of the contained medical device. As a result, the stent valve medical device of the present device is fixedly positioned circumferentially and longitudinally in the delivery system. Thus, the key at the proximal end of the Y-adaptor of FIGS. 6 and 7 can be used to visually indicate the rotational orientation of the stent valve medical device contained in the delivery catheter at the distal end of the delivery system.  
         [0050]    [0050]FIG. 10 depicts another illustrative embodiment of the positioning arrangement of delivery system  10  of FIG. 8. In this alternative embodiment, the positioning member comprises a sleeve  72  having a cross-sectional shape with an elliptical circumference  73 . As a result, the wire frame members or segments of the stent valve are positioned on either side of the major axis of the elliptically shaped sleeve. The orientation of the sleeve is aligned with that of the lock on the proximal end of the inner member to provide visual orientation of the stent valve contained at the distal end of the delivery system.  
         [0051]    [0051]FIGS. 11 and 12 depict top and side views of still another illustrative embodiment of a positioning arrangement of the delivery system of FIG. 1 in which distal end  29  of outer tube  27  is shaped to engage one end of the stent valve medical device. In FIG. 11, the top and bottom of outer tube  27  have been skived or recessed so as to allow the wire frame segments to reside on either side of the tube. Recessed portions  74  and  75  engage the wire frame members of the device when contained in the delivery catheter. FIG. 12 depicts a top view of the outer tube with the sides of the tube beveled or tapered to form a duckbill configuration.  
         [0052]    [0052]FIGS. 13 and 14 depict top and side views of another illustrative embodiment of distal tip portion  17  of the inner member of the delivery system of FIG. 1. In this embodiment, the proximal end  31  of the distal tip portion has been recessed on both sides as indicated by curvilinear surfaces  76  and  77 . As depicted in FIG. 14, these curvilinear surfaces allow the other end as indicated by phantom lines  78  of the stent valve medical device to reside on the oppositely facing surfaces. As depicted in the top view of FIG. 13, the proximal end of curvilinear surface  76  has been rounded to minimize trauma or damage to surrounding tissue or the lyophilized tissue material of the stent valve.  
         [0053]    [0053]FIGS. 15 and 16 depict top and side views of still yet another embodiment of inner member  16  of the delivery system of FIG. 1. In the top view of FIG. 15, proximal end  31  of distal tip portion  17  includes oppositely facing curvilinear surfaces  76  and  77 . Distal end  20  of outer tube  27  has oppositely facing recessed surfaces  74  and  75 . Distal tip portion  17  and outer tube  27  are circumferentially positioned on inner tube  25  such that curvilinear  76  and  77  are 90 degrees out of phase with respect to oppositely facing recessed surfaces  74  and  75 . In this positioning arrangement, the 90 degrees out of phase ends as indicated by phantom lines  78  and  79  of the wire frame stent are engaged by and contained by the recessed surfaces.  
         [0054]    [0054]FIG. 17 depicts a pictorial view of still yet another embodiment of inner member  16  of the delivery system of FIG. 1. To help fluoroscopically visualize the orientation of distal end  20  of proximal portion  18 , two elongated segments of radiopaque material  80  and  81  are diametrically positioned in the distal end of outer tube  27 . These radiopaque markers can be used with any of the embodiments previously discussed to further visualize the orientation of the stent valve medical device or the distal end of the proximal end portion of the inner member.  
         [0055]    [0055]FIG. 18 depicts a pictorial view of yet still another embodiment of inner member  16  and, in particular, distal tip portion  17  of the delivery system of FIG. 1. In this embodiment, tapered proximal end  31  of distal tip portion  17  includes longitudinally offset recesses  45  and  46 . Offset  45  has a diametrically opposed recess on the circumference of tapered proximal end  31 , whereas offset recess  46  likewise has a corresponding diametrically opposed recess on the circumference of the tapered proximal end  31 . These two pairs of diametrically opposed recesses are offset from one another to accept a pair of long struts of, for example, a venous valve in recess pair  46  and to accept a pair of shorter struts in longitudinal recess pair  45 . These offset recesses capture the ends of the two different length struts so as to maintain circumferential orientation of the medical device during placement. Furthermore, the medical device can be rotated with these longitudinally offset recesses for precise placement in the vasculature of a patient.  
         [0056]    [0056]FIGS. 19 and 20 depict pictorial and side views of locking mechanism  47  of the delivery system of the present invention for fixedly positioning the relative position of delivery catheter  11  with respect to dilator or inner member  16 . In this embodiment, a well-known and commercially available Check-Flo valve  48  with side arm  82  is connected to or made part of the proximal end of delivery catheter  11 . This valve has an annular recess therearound as does the distal end of inner member  16 , which includes a well-known Luer-lock connector hub at its distal end. To fix the relative longitudinal position of the delivery catheter and inner member, locking mechanism  47  includes a pair of C-shaped clips, which are interconnected by tie bar  47 . The C-shaped clips of the locking mechanism are each clipped into a respective recess at the distal end of the delivery catheter and inner member so as to fix the relative position of each to one another. This locking mechanism can be readily removed by the attending physician when it is desired to withdraw the delivery catheter from the contained medical device. The locking mechanism advantageously prevents premature deployment of the medical device during the delivery and implantation procedure.  
         [0057]    Enclosed herewith is an element list which is provided as a convenience to relate the various elements of the delivery system as depicted in the drawings and described in the detailed description. This list of elements is provided for illustrative purposes only and is not to be construed to limit the present invention in any manner.  
                                         ELEMENT LIST                                10   delivery system       11   delivery catheter       12   inner lumen of 11       13   proximal end of 11       14   distal end of 11       15   device-containing region of 11       16   inner member or dilator       17   distal tip portion of 16       18   proximal portion of 16       19   intermediate portion of 16       20   blunt distal end of 18       21   irrigation lumen of 11 and 16       22   proximal end region of 35       23   tapered bonding area       24   inner lumen of 16       25   inner tube of 16       26   radiolucent material of 25       27   coaxial outer tube of 16       28   radiopaque material of 27       29   distal end of 27       30   medical device       31   tapered proximal end of 17       32   tapered distal end of 17       33   intermediate portion of 17       34   cylindrical outer surface of 18       35   recessed or flat portion of 18       36   radiopaque marker of 17       37   radiopaque material tube of 11       38   Y-connector       39   main arm of 38       40   side arm of 38       41   hydration lumen       42   lyophilized tissue material of 30       43   radiopaque markers of 30       44   wire frame stent of 30       45   offset recesses of 31       46   offset recesses of 31       47   locking mechanism       48   Check-Flo valve       49   C-shaped clips of 47       50   guide wire       51   tie bar of 47       52   Luer-lock connector hub of 11       53   threaded lock       54   tubing and valve       55   proximal ends of tubes 25, 27       56   Luer-lock connector hub of 16       57   female part of 56       58   male part of 56       59   female part of 52       60   male part of 52       61   distal connector of 38       62   polymer material seal of 53       63   irrigation lumen of 40       64   main arm lumen of 38       65   proximal end of 39       66   apertures at 65       67   apertures at 65       68   slots on 16       69   two prong key       70   cylindrical ring on 25       71   wire frame members       72   sleeve on 25       73   elliptical circumference of 72       74   recessed portions at 29       75   recessed portions at 29       76   curvilinear surfaces of 31       77   curvilinear surfaces of 31       78   distal end of 30       79   proximal end of 30       80   radiopaque material       81   radiopaque material       82   side arm of 48       83   clear or transparent material tube of 11                  
 
         [0058]    It is to be understood that the above-described delivery systems are merely illustrative embodiments of the principles of this invention and that other medical device delivery systems may be devised by those skilled in the art without departing from the spirit and scope of this invention. In particular, the distal end of the proximal portion of the inner member may be configured to engage the proximal end of the medical device positioned in the intermediate portion of the inner member. Furthermore, the proximal end of the distal tip portion of the inner member can be configured in any number of different ways to receive and engage the distal end of the medical device. These configurations are used to engage and rotate the medical device while still being able to determine the orientation of the medical device from the proximal end of the delivery system typically positioned outside of the patient during a purcutaneous vascular procedure.  
         [0059]    Industrial Applicability  
         [0060]    The present invention is useful for placement of a medical implantable device within a human or veterinary patient, and therefore finds applicability in human and veterinary medicine.  
         [0061]    It is to be understood, however, that the above-described device is merely an illustrative embodiment of the principles of this invention, and that other devices and methods for using them may be devised by those skilled in the art, without departing from the spirit and scope of the invention, It is also to be understood that the invention is directed to embodiments both comprising and consisting of the disclosed parts.