Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/501,748 filed Jun. 27, 2011, U.S. Provisional Application No. 61/501,753 filed Jun. 27, 2011 and U.S. Provisional Application No. 61/501,819 filed Jun. 28, 2011 all of which are hereby incorporated by reference herein in their entireties. 
         [0002]    This application is a continuation in part of International Application No. PCT/US2011/022255 filed Jan. 24, 2011, which claims the benefit of U.S. Provisional Application No. 61/298,046 filed Jan. 25, 2010 and U.S. Provisional Application No. 61/298,060 filed Jan. 25, 2010 all of which are hereby incorporated by reference herein in their entireties. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    The field of intralumenal therapy for the treatment of vascular disease states has for many years focused on the use of many different types of therapeutic devices. While it is currently unforeseeable that one particular device will be suitable to treat all types of vascular disease states it may however be possible to reduce the number of devices used for some disease states while at the same time improve patient outcomes at a reduced cost. To identify potential opportunities to improve the efficiency and efficacy of the devices and procedures it is important for one to understand the state of the art relative to some of the more common disease states. 
         [0004]    For instance, one aspect of cerebrovascular disease in which the wall of a blood vessel becomes weakened. Under cerebral flow conditions the weakened vessel wall forms a bulge or aneurysm which can lead to symptomatic neurological deficits or ultimately a hemorrhagic stroke when ruptured. Once diagnosed a small number of these aneurysms are treatable from an endovascular approach using various embolization devices. These embolization devices include detachable balloons, coils, polymerizing liquids, gels, foams, stents and combinations thereof. 
         [0005]    The most widely used embolization devices are detachable embolization coils. These coils are generally made from biologically inert platinum alloys. To treat an aneurysm, the coils are navigated to the treatment site under fluoroscopic visualization and carefully positioned within the dome of an aneurysm using sophisticated, expensive delivery systems. Typical procedures require the positioning and deployment of multiple embolization coils which are then packed to a sufficient density as to provide a mechanical impediment to flow impingement on the fragile diseased vessel wall. Some of these bare embolization coil systems have been describe in U.S. Pat. No. 5,108,407 to Geremia, et al., entitled, “Method And Apparatus For Placement Of An Embolic Coil” and U.S. Pat. No. 5,122,136 to Guglielmi, et al., entitled, “Endovascular Electrolytically Detachable Guidewire Tip For The Electroformation Of Thrombus In Arteries, Veins, Aneurysms, Vascular Malformations And Arteriovenous Fistulas.” These patents disclose devices for delivering embolic coils at predetermined positions within vessels of the human body in order to treat aneurysms, or alternatively, to occlude the blood vessel at a particular location. Many of these systems, depending on the particular location and geometry of the aneurysm, have been used to treat aneurysms with various levels of success. One drawback associated with the use of bare embolization coils relates to the inability to adequately pack or fill the aneurysm due to the geometry of the coils which can lead to long term recanalization of the aneurysm with increased risk of rupture. 
         [0006]    Some improvements to bare embolization coils have included the incorporation of expandable foams, bioactive materials and hydrogel technology as described in the following U.S. Pat. No. 6,723,108 to Jones, et al., entitled, “Foam Matrix Embolization Device”, U.S. Pat. No. 6,423,085 to Murayama, et al., entitled, “Biodegradable Polymer Coils for Intraluminal Implants” and U.S. Pat. No. 6,238,403 to Greene, et al., entitled, “Filamentous Embolic Device with Expansible Elements.” While some of these improved embolization coils have been moderately successful in preventing or reducing the rupture and re-rupture rate of some aneurysms, the devices have their own drawbacks. For instance, in the case of bioactive coils, the materials eliciting the biological healing response are somewhat difficult to integrate with the coil structure or have mechanical properties incompatible with those of the coil making the devices difficult to accurately position within the aneurysm. In the case of some expandable foam and hydrogel technology, the expansion of the foam or hydrogel is accomplished due to an interaction of the foam or hydrogel with the surrounding blood environment. This expansion may be immediate or time delayed but is generally, at some point, out of the control of the physician. With a time delayed response the physician may find that coils which were initially placed accurately and detached become dislodged during the expansion process leading to subsequent complications. 
         [0007]    For many aneurysms, such as wide necked or fusiform aneurysms the geometry is not suitable for coiling alone. To somewhat expand the use of embolization coils in treating some wide necked aneurysms, stent like scaffolds have been developed to provide support for coils. These types of stent like scaffolds for use in the treatment of aneurysms have been described in U.S. Pat. No. 6,605,111 to Bose et al., entitled, “Endovascular Thin Film Devices and Methods for Treating Strokes” and U.S. Pat. No. 6,673,106 to Mitelberg, et al., entitled, “Intravascular Stent Device”. While these stent like devices have broadened the types of aneurysms amenable to embolization therapy, utilization of these devices in conjunction with embolization devices is technically more complex for the physician, may involve more risk to the patient and have a substantial cost increase for the healthcare system. 
         [0008]    To further expand the types of aneurysm suitable for interventional radiological treatment, improved stent like devices have been disclosed in U.S. Pat. No. 5,824,053 to Khosravi et al., entitled, “Helical Mesh Endoprosthesis and Method”, U.S. Pat. No. 5,951,599 to McCrory, entitled, “Occlusion System for the Endovascular Treatment of and Aneurysm” and U.S. Pat. No. 6,063,111 to Hieshima et al., entitled, “Stent Aneurysm Treatment System and Method.” When placed across the neck of an aneurysm the proposed stent like devices purport to have a sufficient density through the wall of the device to reduce flow in the aneurysm allowing the aneurysm to clot, while at the same time having a low enough density through the wall to allow small perforator vessels adjacent to the aneurysm to remain patent. Stent devices of this nature while having the potential to reduce treatment costs have not been realized commercially due to the difficulty in manufacturing, reliability in delivering the devices to the treatment site and an inability to properly position the denser portion of the stent device accurately over the neck of the aneurysm. 
         [0009]    Another cerebrovascular disease state is ischemia resulting from reduced or blocked arterial blood flow. The arterial blockage may be due to thrombus, plaque, foreign objects or a combination thereof. Generally, soft thrombus created elsewhere in the body (for example due to atrial fibrillation) that lodges in the distal cerebrovasculature may be disrupted or dissolved using mechanical devices and or thrombolytic drugs. While guidewires are typically used to disrupt the thrombus, some sophisticated thrombectomy devices have been proposed. For instance U.S. Pat. No. 4,762,130 to Fogarty et al., entitled, “Catheter with Corkscrew-Like Balloon”, U.S. Pat. No. 4,998,919 of Schepp-Pesh et al., entitled, “Thrombectomy Apparatus”, U.S. Pat. No. 5,417,703 to Brown et al., entitled “Thrombectomy Devices and Methods of Using Same”, and U.S. Pat. No. 6,663,650 to Sepetka et al., entitiled, “Systems, Methods and Devices for Removing Obstructions from a Blood Vessel” discloses devices such as catheter based corkscrew balloons, baskets or filter wires and helical coiled retrievers. Commercial and prototype versions of these devices have shown only marginal improvements over guidewires due to an inability to adequately grasp the thrombus or to gain vascular access distal to the thrombus(i.e. distal advancement of the device pushes the thrombus distally). 
         [0010]    Plaque buildup within the lumen of the vessel, known as atherosclerotic disease, is not generally responsive to thrombolytics or mechanical disruption using guidewires. The approach to the treatment of neurovascular atherosclerotic disease has been to use modified technology developed for the treatment of cardiovascular atherosclerotic disease, such as balloons and stents, to expand the vessel at the site of the lesion to re-establish blood flow. For instance, U.S. Pat. No. 4,768,507 to Fischell et al., entitled, “Intravascular Stent and Percutaneous Insertion Catheter System for the Dilation of an Arterial Stenosis and the Prevention of Arterial Restenosis” discloses a system used for placing a coil spring stent into a vessel for the purposes of enhancing luminal dilation, preventing arterial restenosis and preventing vessel blockage resulting from intimal dissection following balloon and other methods of angioplasty. The coil spring stent is placed into spiral grooves on an insertion catheter. A back groove of the insertion catheter contains the most proximal coil of the coil spring stent which is prevented from springing radially outward by a flange. The coil spring stent is deployed when an outer cylinder is moved proximally allowing the stent to expand. Other stent systems include those disclosed in U.S. Pat. No. 4,512,338 to Balko, et al., entitled, “Process for Restoring Patency to Body Vessels”, U.S. Pat. No. 5,354,309 to Schnepp Pesch et al., entitled, “Apparatus for Widening a Body Cavity” and U.S. Pat. No. 6,833,003 to Jones et al., entitled, “Expandable Stent and Delivery System”. While the aforementioned devices may have the ability to access the cerebrovasculature, they lack sufficient structural coverage of the lesion to achieve the desired patency of the vessel without the use of a balloon device. 
       SUMMARY OF THE INVENTION 
       [0011]    In accordance with one aspect of the present invention there is provided a medical device deployment system for repairing a body lumen in a mammal. The medical device deployment system includes a stent device, a delivery system and a catheter. The stent device is positioned at the distal end of the delivery member and disposed within the lumen of the catheter. The stent device takes the form of a helically wound backbone or primary member having side extension members spaced apart along the length and extending outwardly from the backbone. The side extension members generally have two ends where one end is fixedly coupled to the backbone and the other end extending from the backbone is free, meaning it is typically uncoupled to any other structural member. As the backbone takes successive helical turns, the side extension members may be positioned adjacent to, intermesh or overlap the side extension members or backbone of subsequent or previous helical turns, generally forming a tubular structure. The adjacency, intermeshing or overlapping side extension members create a lattice work of apertures between turns of the backbone. The size and distribution of the apertures is a function of the diameter, length and shape of the side extension members and the distance between turns of the backbone. The stent device is formed of a resilient material and has a first constrained elongate tubular configuration for delivery to a target site within a body lumen and a second unconstrained expanded tubular configuration for deployment at the target site. The delivery system includes an inner member and an outer member. The inner and outer members both have distal and proximal ends. The outer member is tubular having a lumen extending between its proximal and distal ends and is preferably torque-able. The inner member is elongate, torque-able and slidably disposed within the lumen of a tubular outer member. The distal end of the inner member extends distal to the distal end of the outer member. The stent device is mounted on the distal end of the inner member where the distal end of the stent device is secured to the distal end of the inner member by an electrolytically severable joint. The proximal end of the stent device is secured to the distal end of the outer member by another electrolytically severable joint. Rotation of the inner member relative to the outer member in one direction causes the stent device to wind itself on to the inner member distal end while decreasing in diameter whereas rotation of the inner member in an opposite direction causes the stent device to increase in diameter expanding away from the inner member. The mounted stent device is wound to a first configuration having a reduced diameter and is positioned within the catheter lumen. The proximal ends of the inner member and outer member are maintained relative to each other so that the stent remains constrained on the inner member distal end. Additionally, provided that the inner and outer members rotate relative to each other the catheter wall will also provide a constraint to the stent device to maintain the stent in a reduced diameter. When the stent device is suitably positioned at a target site, a power supply coupled to the proximal end of the inner member provides energy through the inner member to its distal end, through the electrolytically severable joint and stent device such that the electrolytically severable joint severs, thereby releasing the stent device from the inner member. The power supply (or a separate power supply) coupled to the proximal end of the outer member provides energy to its distal end, through the electrolytically severable joint and stent device such that the electrolytically severable joint severs, thereby releasing the stent device from the outer member. 
         [0012]    In accordance with another aspect of the present invention there is provided a stent device having a backbone and side extension members which may take various configurations comprising any of the following: side extension members on each side of the backbone which are uniformly spaced along the length of the backbone; side extension members on each side of the backbone which are not uniformly spaced along the length of the backbone; side extension members having a curved shape; side extension members having a straight shape; side extension members extending from the backbone in an angled direction; side extension members having different lengths; side extension members having apertures; side extension members having radio-opaque markers; side extensions having an enlarged tabular end; backbones having apertures; backbones having radio-opaque marker(s); backbones having a curvilinear shape. 
         [0013]    In accordance with still another aspect of the present invention there is provided a method of reconstructing a body lumen having a defect using a stent device according to an embodiment of the present invention. The method comprises the steps of: positioning a stent device deployment system within a vessel adjacent a target site; retracting the catheter relative to the delivery system, rotating the inner member relative to the outer member thereby expanding the stent device adjacent the target site; controlling the proximity of the side extension members on one turn of the stent device relative to the side extension members on an adjacent turn of the stent device during deployment of the stent adjacent the target site; releasing the stent device from the inner member distal end electrolytically; and, releasing the stent device from the outer member distal end. 
         [0014]    In accordance with still another aspect of the present invention there is provided a method of reconstructing a body lumen having a defect, such as an aneurysm, using a stent device according to an embodiment of the present invention in conjunction with embolization devices, such as embolic coils. The method comprises the steps of: providing a stent device having a configuration adapted to allow the delivery of an embolization device through the side wall of the stent when said stent is in a deployed configuration; positioning a stent device deployment system having a delivery system and a catheter within a vessel adjacent a target site; retracting the catheter relative to the delivery system, deploying the stent device adjacent the target site by rotating a member of said delivery system; controlling the proximity of the side extension members on adjacent turns of the stent device during deployment of the stent adjacent the target site; releasing the stent device from the delivery system inner member distal end electrolytically; releasing the stent device from the delivery system outer member distal end; positioning an embolization delivery system through the wall of the deployed stent; delivering an embolization device to the aneurysm wherein said embolization device is supported by the stent device; releasing said embolization devices. 
         [0015]    In accordance with yet another aspect of the present invention there is provided a reconstruction device having first and second configurations for delivery and deployment, respectively, where the reconstruction device is operable between the first and second configurations. The reconstruction device further including a primary member having a helical shape and a plurality of extension members with each extension member having first and second ends where one of the first and second ends is fixedly coupled to the primary member and the other end is uncoupled to any other member of said reconstruction device. 
         [0016]    In accordance with yet another aspect of the present invention there is provided a reconstruction device having first and second configurations for delivery and deployment, respectively, where the reconstruction device is operable between the first and second configurations. The reconstruction device further including a primary member having a helical shape and a plurality of extension members with each extension member having first and second ends and a body portion between said ends, where one of the first and second ends is fixedly coupled to the primary member and the body portion or other end is uncoupled to any other member of said reconstruction device that interconnects with said backbone. 
         [0017]    In accordance with yet another aspect of the present invention there is provided a reconstruction device having first and second configurations for delivery and deployment, respectively, where the reconstruction device is operable between the first and second configurations. The reconstruction device further including a primary member having a helical shape and a plurality of extension members with each extension member having first and second end portions and a body portion between said end portions, where one of the first and second end portions is fixedly coupled to the primary member and the body portion or other end is uncoupled to any other member of said reconstruction device that interconnects with said backbone. 
         [0018]    In accordance with still yet another aspect of the present invention there is provided a reconstruction device wherein the primary helical member is formed of a resilient non-absorbable non-erodible material and a plurality of the extension members are formed of an absorbable or bio-erodible material. 
         [0019]    In accordance with still yet another aspect of the present invention there is provided a reconstruction device wherein the primary helical member is formed of a resilient material and includes an absorbable and or erodible material and a plurality of the extension members are formed of a resilient material and includes an absorbable and or erodible material. 
         [0020]    In accordance with yet still another aspect of the present invention there is provided a reconstruction device comprising a biocompatible material. Suitable resilient materials include metal alloys such as Nitinol(NiTi), titanium, chromium alloy, stainless steel. Additional materials include polymers such as polyolefins, polyimides, polyamides, fluoropolymers, polyetheretherketone(PEEK), cross-linked PVA hydrogel, polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), porous high density polyethylene (HDPE), polyurethane, and polyethylene terephthalate, or biodegradable materials such as polylactide polymers and polyglycolide polymers or copolymers thereof and shape memory polymers. The medical device may comprise numerous materials depending on the intended function of the device. These materials may be formed into desired shapes or attached to the device by a variety of methods which are appropriate to the materials being utilized such as laser cutting, injection molding, spray coating and casting. 
         [0021]    In accordance with another aspect of the present invention there is provided a reconstruction device having a coating formed of a biocompatible, bioerodible and biodegradable synthetic material. The coating may further comprise one or more pharmaceutical substances or drug compositions for delivering to the tissues adjacent to the site of implantation, and one or more ligands, such as peptides which bind to cell surface receptors, small and/or large molecules, and/or antibodies or combinations thereof for capturing and immobilizing, in particular progenitor endothelial cells on the blood contacting surface of the medical device. 
         [0022]    In accordance with yet another aspect of the present invention there is provided a delivery system having elongate inner and outer members which includes tip markers at the distal ends of the inner and outer member and a stent positioning marker located on the inner member proximal to the tip marker. 
         [0023]    In accordance with still another aspect of the present invention there is provided a method of reconstructing a body lumen having a defect, such as an atherosclerotic lesion, using a stent device according to an embodiment of the present invention. The method comprises the steps of: providing a stent device having a configuration adapted to treat the lesion in a deployed configuration; positioning a stent device deployment system having a delivery system and a catheter within a vessel adjacent a target site; retracting the catheter relative to the delivery system, deploying the stent device adjacent the target site by rotating a member of said delivery system; controlling the proximity of the side extension members on adjacent turns of the stent device during deployment of the stent adjacent the target site; releasing the stent device from the delivery system inner member distal end electrolytically; releasing the stent device from the delivery system outer member distal end; 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a partial cross-sectional of a stent deployment system according to an embodiment of the present invention. 
           [0025]      FIG. 2A through 2D  are enlarged partial cross-sectional views of the proximal end and distal end of the stent deployment system according to an embodiment of the present invention. 
           [0026]      FIG. 3  is a side view of a deployed stent device according to an embodiment of the present invention. 
           [0027]      FIGS. 4A through 4L  are partial flat pattern views of stent devices according to embodiments of the present invention. 
           [0028]      FIGS. 5A through 5F  are partial cross-sectional views illustrating a method of delivering and deploying a stent device within a vessel at a target site adjacent an aneurysm according to an embodiment of the present invention. 
           [0029]      FIGS. 6A through 6F  are partial cross-sectional views illustrating a method of delivering and deploying a stent device within a vessel at a target site adjacent an atherosclerotic lesion according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    Methods and systems for performing vascular reconstruction and revascularization in a desired area of the body are herein described.  FIG. 1  illustrates a medical device deployment system  10  according to an embodiment of the present invention. System  10  includes a catheter  20  having distal and proximal ends  22  and  24  respectively and a lumen  25  extending there through. Coupled to proximal end  24  is a catheter hub  26  that has a standard Luer fitting. Positioned within lumen  25  is an elongate delivery system  28  comprising an elongate tubular outer member  30  having distal and proximal ends  32  and  34  and an elongate inner member  36  having distal and proximal ends  38  and  40 . Inner member  36  is slidably and rotatably positioned within the lumen of tubular outer member  30 . The distal end  38  of inner member  36  is positioned distal to distal end  32  of outer member  30 . The proximal end  40  of inner member  36  extends proximal to proximal end  34  of outer member  30 . Coupled to proximal end  34  of outer member  30  is outer knob  42 . Coupled to proximal end  40  of inner member  36  is inner knob  44 . A retainer member  45  is removably coupled to inner knob  44  and outer knob  42  restricts rotational and axial movement of inner member  36  relative to outer member  30  until removed. The inner and outer knobs  44  and  42  together with the retainer member  45  and proximal ends  40  and  34  of the inner and outer member  36  and  30  generally constitute a rudimentary handle assembly for delivery system  28 . As can be appreciated a more stylistic handle with additional features is contemplated. Stent device  50  is mounted on distal end  38  of inner member  36  and positioned within lumen  25  at catheter distal end  22 . Stent device  50  has a distal portion  52  and a proximal portion  54 . The deployment system  10  also includes a power supply having 60 having a lead  62  and electrode connector  64  that couples to proximal end  34  of outer member  30  and a lead  63  and electrode connector  65  that couples to proximal end  40  of inner member  36 . A ground lead  66  and electrode pad  67  are also coupled to power supply  60 . 
         [0031]      FIG. 2A  illustrates an enlarged partial cross-sectional view of catheter distal end  22 . Slidably positioned within lumen  25  of catheter  20  are outer member  30  and inner member  36  of delivery system  28 . Outer member  30  is shown partially sectioned to reveal an internal support member  70  preferably formed as a laser cut metallic hypotube to provide flexibility and torque-ability. Alternatively, the internal support member may take the form of a wound coil assembly using wire having a round, flat or other cross-sectional shape. Support member  70  preferably has an electrically insulative cover member  72  extending over a substantial portion of the surface along its length. Cover member  72  may take the form of a thin conformal coating or shrink tubing Inner member  36  also includes a support member  74  that is preferably formed as a laser cut metallic hypotube to provide flexibility and torque-ability. Support member  74  may alternatively take the form of a torqueable wire or cable assembly. Support member  74  includes an insulative cover member  76  that extends over a substantial portion of the surface along its length. Cover member  76  may take the form of a thin conformal coating or shrink tubing. Suitable coating and shrink tubing materials include insulative polymers such as parylene, polyimides, polyamides, fluoropolymers, polyolefins, polyesters, polysiloxanes including co-polymers and composites thereof. 
         [0032]    The proximal portion  54  of stent device  50  is shown in a first configuration having a reduced diameter substantially positioned over the insulative cover member  76 . Primary member  80  is shown wound around inner member  36  producing a number of turns or winds such as wind  81 . Representative side extension members  82  and  84  extend from wind  81  of primary member  80  in a direction generally parallel to the longitudinal axis of delivery system  28 . Wind  81  has an adjacent wind  85  also that includes representative side extension member  86  that extend from wind  85  in a direction generally parallel to the longitudinal axis of delivery system  28  and is positioned between side extension members  82  and  84  in an intermeshing configuration. The orientation of side extension members in a longitudinal direction parallel to the longitudinal axis of the delivery system allows stent  50  be reduced to a very small diameter for positioning in a small diameter catheter having the ability to access small diameter vessels. Proximal end  88  of stent device  50  is shown having no side extension members and includes a proximal tab  90 . Tab  90  is connected to distal end  32  of outer member  30  by an electrolytically severable joint member  92  at joint end  94  as shown in magnified view  FIG. 2B . Joint member  92  extends through insulative cover member  72  and is in electrical communication with support member  70 . Joint member  92  may be joined to support member  70  by soldering or welding (not shown). Joint end  94  is electrically coupled to tab  90  through the use of solder  95 . Other means of joining joint end  94  to tab  90  may also be suitable such as forms of brazing or welding including laser welding and the use of electro-conductive adhesives. Joint member  92  includes an insulative cover  96  over the end coupled to support member  70 . Joint member  92  has an exposed portion  98  that does not have an insulative covering. 
         [0033]      FIG. 2C  illustrates another enlarged partial cross-sectional view of catheter distal end  22 . The distal portion  52  of stent device  50  is shown in a first configuration having a reduced diameter substantially positioned over the insulative cover member  76 . Distal end  100  of stent device  50  is shown having no side extension members and includes a distal tab  102 . Tab  102  is connected to distal end  38  of inner member  36  by an electrolytically severable joint member  103  at joint end  104  as shown in magnified view  FIG. 2D . Joint member  103  extends through insulative cover member  76  and is in electrical communication with support member  74 . Joint member  103  may be joined to support member  74  by soldering or welding (not shown). Joint end  104  is electrically coupled to tab  102  through the use of solder  105 . Other means of joining joint end  104  to tab  102  may also be suitable such as forms of brazing or welding including laser welding and the use of electro-conductive adhesives. Joint member  103  includes an insulative cover  106  over the end coupled to support member  74 . Joint member  102  has an exposed portion  108  that does not have an insulative covering. Once secured to joint members  92  and  103 , stent device  50  is coated using an insulative coating such as parylene. This coating ensures that the exposed portions  98  and  108  of joint members  92  and  103  are the most susceptible portions for electrolytic dissolution when stent device  50  released at a target site by supplying power to delivery system  28 . 
         [0034]      FIG. 3  illustrates detail of stent device  50  in a second configuration having an expanded diameter. The backbone or primary member  80  is shown in having helical shape along with a plurality of side extension members and turns or winds represented by side extension members  82 ,  84  and  86  and winds  81  and  85 . As depicted, the side extension members of the stent device generally have one end secured to the backbone and the other end uncoupled which is unlike previous stents described in the art. This configuration allows the side extension members of the present invention to act as individual cantilevers providing an improved ability to conform to discrete contours within the vasculature. Alternatively, both ends of the side extension members may be coupled to the backbone or primary member, forming a looped structure for example, as long as the side extension member is discrete and not fixedly coupled to any other structural member. Prior art helical stents formed of a ladder or mesh structure in which side extension members do not have a free end or are not discrete, such as those described in U.S. Pat. No. 6,660,032 to Klumb et al, entitled, “Expandable Coil Endoluminal Prosthesis” or U.S. Pat. No. 5,824,053 to Koshravi et al, entitled “Helical Mesh Endoprosthesis and Method of Use”, do not have the same ability to conform to discrete contours of a lesion within the vasculature and instead form a wide area “tented” surface. In the expanded diameter second configuration of stent device  50  the side extension members that extended generally parallel to the longitudinal axis of the delivery system in the reduced diameter first configuration of stent device  50  are oriented at an angle to the longitudinal axis of the delivery system. Stent device  50  is shown with side extension members  82  and  84  of wind  81  intermeshing with side extension member  86  of the adjacent wind  85 . The intermeshing of these side extension members creates interstices or apertures between the side extension members. The size, shape and distribution of the interstices is dependant upon the size, shape and distribution of the side extension members of a wind and an adjacent wind side extension members and the degree of intermeshing defined in part by the pitch of the backbone or primary member  80 . The stent device  50  may have a constant diameter in the range of 1 to 50 mm, and preferably between 2 and 15 mm or as shown in FIG.  3 ., have ends  100  and  88  that are larger in diameter relative to other stent device portions. The diameters of the side extension members have a range of between 0.0001 and 0.025 inches with a preferred range of between 0.002 to 0.010 inches. The spacing between side extension members range between 0.001 and 0.250 inches with a preferred range between 0.002 and 0.060 inches. Stent device  50  may have regions such as ends  100  and  88  that do no have any side extension members. The wound pitch of primary member  80  is shown to be fairly constant however the pitch may be varied along a portion of a stent device dependant upon the functional requirements of the stent. For instance, a primary member having a small pitch may cause the intermeshing side extension members to have a small interstice between the tip of the side extension member and the primary member of an adjacent wind reducing the stent device porosity. Additionally, a primary member having a small pitch may cause the side extension members of one wind to overlap with the primary member of an adjacent wind. 
         [0035]    In addition to the pitch of the stent backbone having an influence on the overall porosity and porosity distribution of the stent device there exists numerous variations in the size shape and distribution of side extension members that may also influence porosity.  FIGS. 4A through 4E  illustrate partial flat patterns of some variations of side extension members relative to a backbone that may affect different aspects of stent performance including porosity and porosity distribution when formed in a helical shape. In one pattern variation shown in  FIG. 4A , a stent device has a primary backbone  140  with side extension members  142  and  143 , having generally similar diameters and lengths, extending from opposite sides of backbone  140 . Side extension member  144 , positioned adjacent extension member  142  has a similar length to extension  142  however may have a smaller diameter. The alternating pattern of side extension members having different diameters may be extended along backbone  140 .  FIG. 4B  depicts another pattern variation in which a stent device has a primary backbone  145  and side extension members  147  and  148 , with generally similar diameters and lengths extending from opposite sides of backbone  145  in a curvilinear shape.  FIG. 4C  illustrates another pattern variation in which a stent device has a primary backbone  150  and side extension members  152  and  154  which are positioned on only one side of the backbone  150 .  FIG. 4D  shows still another pattern variation in which a stent device has a primary backbone  155  and groups of side extension members  157  and  158  are positioned in an alternating configuration on opposite sides of the backbone  155 .  FIG. 4E  depicts still another pattern variation in which a stent device has a primary backbone  160  and side extension members  162  and  163  with generally similar diameters and lengths extending from opposite sides of backbone  160 . Additionally, the side extension members may progressively have shorter lengths, such as side extension member  164 , to provide a tapered configuration.  FIG. 4F  illustrates yet still another pattern in which a stent device has a primary backbone  165  and side extension members,  167  and  168  with generally similar diameters and lengths extending from opposite sides of backbone  165 . Additionally the side extension members contain apertures  169 .  FIGS. 4G and 4H  illustrate partial flat patterns of some variations of a backbone relative to side extension members that may affect different aspects of stent performance including porosity and porosity distribution as well as radiographic visibility when formed in a helical shape.  FIG. 4G  depicts a pattern of a stent device that has a primary backbone  170  and side extension members  172  and  173 , with generally similar diameters and lengths extending from opposite sides of backbone  170 . Along the length of backbone  170  there is a plurality of apertures  174 .  FIG. 4H  depicts a pattern of a stent device that has a primary backbone  175  and side extension members  177  and  178 , with generally similar diameters and lengths extending from opposite sides of backbone  175 . Along the length of backbone  175  there is a radio-opaque member  179 . The radio-opaque member  179  provides fluoroscopic visualization of the stent during the deployment procedure. For a stent device having an expanded diameter and a pre-set initial overlap of side extension members upon each helical turn of the backbone, the radio-opaque member  179  provides a visual indication of the stent pitch. As the spacing between adjacent turns of radio-opaque member  179  decreases, the amount of side extension member overlap with adjacent turns increases.  FIG. 4I  depicts yet another pattern of a stent device that has a primary backbone  180  and a plurality of side extension members represented by side extension members  181  and  182 . Side extension members  181  and  182  are positioned on opposite sides of backbone  180  in a generally mirrored fashion for this configuration. Side extension members  181  generally take the form of an open ended loop, where a first end of the extension member loop is connected to the backbone and the second end  183  is adjacent the backbone but are not connected. Side extension members  182  generally take the form of a closed loop, where two ends  184  of the extension member loop are connected to backbone  180 . As can be appreciated, side extension members  182  form a discrete side unit where it is unconnected to other side extension members except through the backbone  180 . From a broader perspective two ends  184  may be considered as a first end region coupled to the backbone and a second end region  185 , as shown, is free or uncoupled to any other structural member. While these loops are shown generally “circular”, the size and shape of the loop may take the form of other geometric shapes and patterns to be commensurate with the desired properties of the formed stent. For instance the loops may be rectangular, triangular or form a flattened spiral.  FIG. 4J  illustrates another pattern of a stent device according to an embodiment of the present invention that has a primary backbone  186  and a representative side extension member  187 . While a first end of side extension member  187  is integrally coupled to backbone  186 , the second end of the side extension member is uncoupled to the backbone and takes the form of an enlarged tabular end  188 . This tabular end  188  is preferably rounded as to be atraumatic to the vessel wall and may include a marker element  189 . Preferably marker element  189  is radio-opaque for use in fluoroscopy using known materials such as gold, platinum, tantalum, tungsten, etc., however marker materials suitable for direct visual or magnetic resonance imaging are also contemplated. Marker element  189  may be formed using coining techniques in which a round marker is press fit into a slightly smaller opening positioned on tabular end  188 . Alternatively, marker  189  may be printed, coated, electro-deposited, riveted, glued, recessed or raised relative to tabular end  188 . More broadly, an entire stent device or portion thereof may be coated with a radio-opaque material to provide visibility under fluoroscopy. While the marker shown in  FIG. 4J  is positioned at tabular end  188 , the marker may be positioned at any location on the side extension member. For instance the side extension member may take the form of a threaded member and a marker take the form of a coil that is wound over the side extension member.  FIG. 4K  depicts still yet another flat pattern of a stent device in which the backbone  190  takes a curvilinear shape. For representative simplicity, backbone  190  is shown as being somewhat sinusoidal. Side extension member  192 , also shown to be curvilinear, extends from a peak on backbone  190 . As can be appreciated, side extension members such as side extension member  192  may extend from different locations on backbone  190 .  FIG. 4L  illustrates a stent pattern where backbone  194  has side extension members represented by side extension member  195 . Along its length, backbone  194  has a first width  196  and a second width  197 . To impart some stretch resistance for the finished stent width  197  is shown to be greater than width  196 . The amount of stretch resistance imparted in the finished stent is related to the relative difference between the two widths. The larger width may range from 1.01 to 100 times the width of the smaller width with a preferable range of 1.5 to 20 times. While  FIG. 4L  shows two such differing widths of the backbone, a stent may have multiple regions of differing width to make the stent suitable for a particular anatomy and clinical application. As with any of the aforementioned stent device pattern variations, these patterns may extend along the entire length of the backbone or only a portion thereof and in some instances features of various patterns may be provided in a combined fashion to form stent devices having unique performance characteristics. Preferably stent devices of the present invention comprise a biocompatible resilient material. Suitable resilient materials include metal alloys such as nitinol, titanium, stainless steel. Additional suitable materials include polymers such as polyimides, polyamides, fluoropolymers, polyetheretherketone(PEEK) and shape memory polymers. As can be appreciated, embodiments of stent devices of the present invention may be formed in part or entirely of bioabsorbable and or bioerodible materials such as polycaprolactone (PCL), polyglycolic acid (PGA), polydioxanone (PDO) and combinations thereof to allow the stent to temporarily serve structural clinical applications, deliver pharmacological compounds and then dissolve over time. These materials may be formed into desired shapes by a variety of methods which are appropriate to the materials being utilized such as laser cutting, thermal heat treating, vacuum deposition, electro-deposition, vapor deposition, chemical etching, photo-chemical etching, electro etching, stamping, injection molding, casting or any combination thereof. Preferably the stent backbone and the side extension members are integrally formed. The distance a side extension member extends from the backbone is dependant upon a specific stent design but a typical range includes between 0.5 to 100 times the width of the backbone and a preferred range being about 0.75 to 25 times the backbone width. The backbone widths have a general range of about 0.0005 in to 0.250 in with a preferred range of about 0.001 in to 0.100 in. While various configurations of side extension members, backbones and a discussion of pitch have been provided, the features of a particular stent design features are heavily dependant upon the clinical application and location of the stent. For instance, stents placed in vessels known to exhibit substantial pulsatility may require that the stent be designed to have end regions which are larger in diameter than the middle portion of the stent to better anchor the stent at the target location. Additionally, the width of the backbone may vary to provide regions of the stent which are less susceptible to elongation, thereby creating a stent that has localized stretch resistant properties which aids in reducing stent migration. Stents sufficient for treating an aneurysm without the aid of other embolization devices positioned within the aneurysm may require that the porosity of the deployed stent in the region of the aneurysm neck be less than about 30 percent. Additionally, stents for treating aneurysm in certain locations may require that the porosity across the neck be less than 30 percent however the porosity adjacent either side of the aneurysm neck be greater than 40 percent and have dimensions as not to occlude small perforator vessels adjacent the aneurysm neck. Stents used to treat fusiform aneurysms may be considerably longer than stents for berry aneurysms. Stents for use in treating a stenotic lesion may require more or less than 50 percent porosity however side member geometry should be designed to keep fragmented plaque trapped between the exterior wall of the stent and interior wall of the vessel. 
         [0036]    As previously discussed, a specific stent device design is heavily dependant upon the clinical application for the device and may include materials or coatings to improve the biocompatibility of the device such as coatings that include ligands adapted to capture endothelial progenitor cells within the vasculature. Additionally, the stent device may include portions of the device such as side extension members which are formed of bio-erodible or bio-absorbable materials and or materials suitable for the delivery of pharmacological or therapeutic agents adapted to encourage healing during the treatment of aneurysms or reduction of plaque or restenosis during the treatment atherosclerotic lesions. Materials and coating process technology suitable for application to the present invention are described in U.S. Patent Application Publication No: 20070128723 A1 to Cottone et al., entitled, “Progenitor Endothelial Cell Capturing with a Drug Eluting Implantable Medical Device” herein incorporated by reference in its entirety. 
         [0037]      FIGS. 5A through 5F  illustrate a method of deploying a stent device adjacent a vascular defect according to one embodiment of the present invention. The deployment system is positioned within a target vessel  200  having a bulging vascular defect known as an aneurysm  202 . The interior of the aneurysm is coupled to the lumen of the vessel at aneurysm neck  204 . The distal end of catheter  20 , including stent device  50  is positioned adjacent aneurysm neck  204 . Stent device  50 , being in its first configuration for delivery, is wound onto and coupled to the distal end of inner member  36  and additionally coupled to outer member  30  of delivery system  28 . Positioning of stent device  50  relative to aneurysm neck  204  may be aided with a radio-opaque centering marker positioned beneath the stent on inner member  36  (not shown). Catheter  20  is retracted such that catheter marker  23  is positioned proximal to proximal tab  90  of stent device  50 . At the proximal end(the collective handle assembly) of deployment system  10 , retainer member  45  is removed allowing axial and rotational movement of inner member  36  and outer member  30  relative to each other. As inner knob  44  is rotated relative to outer knob  42 , inner member  36  rotates causing stent device  50  to unwind and expand. The expansion of stent device  50  may be controlled through the rotation and longitudinal movement of inner knob  44  relative to outer knob  42 . Movement of the knobs  44  and  42  relative to each other provides the physician with the ability to control the relative proximity of side extension members positioned on adjacent winds. The expansion of stent device  50  continues until it contacts the inner wall of vessel  200 . At this point in the deployment process, should the physician desire to not proceed with treating the lesion or to reposition stent device  50 , knob  44  may be rotated in the opposite direction relative to knob  44  and wind stent device  50  to a reduced diameter onto inner member  36  for subsequent repositioning and redeployment or removal. Should the physician desire to release stent device  50  at the target site, power supply  60  is used to supply energy to the inner and outer member proximal ends to cause the electrolytically severable joint members  103  and  92  to sever, thereby releasing distal and proximal tabs  102  and  90  of stent device  50  from delivery system  28 . The delivery system  28  and catheter  20  may then be removed from the target site. 
         [0038]      FIGS. 6A through 6F  illustrate a method of deploying a stent device adjacent a vascular defect according to another embodiment of the present invention. The deployment system is positioned within a target vessel  300  having an atherosclerotic lesion comprising plaque deposits  302  and  304  creating a stenosis within the vessel restricting distal blood flow. The distal end of catheter  20 , including stent device  50  is positioned adjacent plaque deposits  302  and  304 . Stent device  50 , being in its first configuration for delivery, is wound onto and coupled to the distal end of inner member  36  and additionally coupled to outer member  30  of delivery system  28 . Positioning of stent device  50  relative to plaque deposits  302  and  304  may be aided with a radio-opaque centering marker positioned beneath the stent on inner member  36  (not shown). Catheter  20  is retracted such that catheter marker  23  is positioned proximal to proximal tab  90  of stent device  50 . At the proximal end(the collective handle assembly) of deployment system  10 , retainer member  45  is removed allowing axial and rotational movement of inner member  36  and outer member  30  relative to each other. As inner knob  44  is rotated relative to outer knob  42 , inner member  36  rotates causing stent device  50  to unwind and being formed from a resilient material such as nitinol move from a first configuration having a reduced diameter to expand. The expansion of stent device  50  may be controlled through the rotation and longitudinal movement of inner knob  44  relative to outer knob  42 . Movement of the knobs  44  and  42  relative to each other provides the physician with the ability to control the relative proximity of side extension members positioned on adjacent winds. The expansion of stent device  50  continues until it contacts the inner wall of vessel  300  distal and proximal to plaque deposits  302  and  304 . At this point in the deployment process, should the physician desire to not proceed with treating the lesion or to reposition stent device  50 , knob  44  may be rotated in the opposite direction relative to knob  44  and wind stent device  50  to a reduced diameter onto inner member  36  for subsequent repositioning and redeployment or removal. Should the physician desire to release stent device  50  at the target site, power supply  60  is used to supply energy to the inner and outer member proximal ends to cause the electrolytically severable joint members  103  and  92  to sever, thereby releasing distal and proximal tabs  102  and  90  of stent device  50  from delivery member  28 . The delivery system  28  and catheter  20  may then be removed from the target site. Although stent device  50  is in an expanded second configuration, a portion of stent device  50  may be partially constrained by plaque deposits  302  and  304 . The resilient nature of stent device  50 , being in an expanded configuration and slightly constrained by the lesion and vessel, creates chronic outward force which is applied to plaque deposits  302  and  304  as well as vessel  300 . The chronic outward of force applied by the stent device  50  is a result of many different design features of the stent including the dimensions and geometry of the backbone or primary member, the phase transformation temperature, Af, of the nitinol used and the shape set normal unconstrained expanded diameter of the stent. When properly designed, the chronic outward force of stent device  50  allows the gradual expansion of the stent diameter in the vicinity of the plaque deposits  302  and  304  to thereby compress the plaque deposits thus reducing the restriction to blood flow in the region. Alternatively, a balloon device may be positioned within the lumen of the deployed stent device  50  and inflated to accelerate the compression of plaque deposit thereby permitting immediate revascularization. 
         [0039]    Novel devices, systems and methods have been disclosed to perform vascular reconstruction and revascularization procedures within a mammal. Although preferred embodiments of the invention have been described, it should be understood that various modifications including the substitution of elements or components which perform substantially the same function in the same way to achieve substantially the same result may be made by those skilled in the art without departing from the scope of the claims which follow.

Technology Category: a