Abstract:
A method of protecting the coating on a reconfigurable coated workpiece having a first end and a second end is provided in one embodiment of the present invention. This embodiment includes providing an encasing hollow deformable membrane, positioning the first end of the reconfigurable coated workpiece adjacent to an entrance orifice of the membrane, enlarging the entrance orifice and the inside cavity of the membrane, inserting the reconfigurable coated workpiece into the enlarged entrance orifice and into the inside cavity and decreasing the size of the inside cavity of the membrane until an inside surface of the cavity contacts the coating of the workpiece.

Description:
FIELD OF THE INVENTION 
     The present invention regards protecting a workpiece during its manufacture or reconfiguration. More specifically the present invention regards reducing the probability of damaging a coating on a workpiece during the workpiece&#39;s manufacture or reconfiguration by using a protective membrane. 
     BACKGROUND 
     Articles of manufacture are regularly coated for numerous and varying reasons. For example, they may be coated to protect them from the intrusive handling they can be subjected to during their manufacture and to protect them from the severe environmental conditions they can encounter after they are manufactured. In either circumstance, as well as in others, damage to the coating of a workpiece, resulting from the handling, mishandling or reconfiguration of the workpiece, is an unwanted result. 
     When the coating of a workpiece becomes scratched or otherwise damaged during its manufacture, the scratches can promote the deterioration of not only the coating but also the workpiece itself by exposing the workpiece&#39;s surface to its surroundings. For instance, should the workpiece be employed in a corrosive environment, its errantly exposed surface would be more vulnerable to corrosion than if its coating were completely intact. 
     Moreover, the scratches and inconsistencies in the coating of a workpiece may also reduce the effectiveness of the finished product. For example, should the coating be used to uniformly deliver some type of releasable substance, inconsistencies in the coating can foster uneven and non-homogeneous delivery of the releasable substance to the deployed product&#39;s final surroundings. 
     An expandable coated stent is one specific example of the coated workpieces described above. Expandable stents are tube-like medical devices designed to support the inner walls of a vessel or lumen within the body of a patient. These stents are typically positioned within a targeted lumen of the body and then expanded to provide internal support for the lumen. These stents may be self-expanding or, alternatively, may require external forces to expand them. In either case they are typically deployed through the use of a catheter of some kind. These catheters typically carry the stents at their distal end. 
     Due to the interaction of the stent with the inner walls of the lumen, stents have been coated to enhance their effectiveness. These coatings may, among other things, be designed to facilitate the acceptance of the stent into its applied surroundings or to facilitate the delivery of therapeutic to the lumen and its surroundings. When the coating is haphazardly applied or has somehow been removed during the stent&#39;s manufacture, both the stent&#39;s useable life span and its effectiveness can be reduced. 
     The coatings on these stent may be applied at various times during its life cycle including during its manufacture, during its placement onto the distal end of the delivery catheter, and contemporaneous with the medical procedure being performed. At each of these times the coating may be at risk of being scratched, damaged or otherwise removed from the surface of the stent. For example, during their manufacture, stents are often crimped onto the distal end of the delivery catheter. During this crimping the mechanical arms of a crimper may come in contact with the coating of the stent as the arms act to reduce the diameter of the stent. This compressive contact can scratch, indent, wipe-off or otherwise breach the integrity of the coating. 
     SUMMARY OF THE INVENTION 
     A method of protecting the coating on a reconfigurable coated workpiece having a first end and a second end is provided in one embodiment of the present invention. This embodiment includes providing an encasing hollow deformable membrane, positioning the first end of the reconfigurable coated workpiece adjacent to an entrance orifice of the membrane, enlarging the entrance orifice and the inside cavity of the membrane, inserting the reconfigurable coated workpiece into the enlarged entrance orifice and into the inside cavity, and decreasing the size of the inside cavity of the membrane until an inside surface of the cavity contacts the coating of the workpiece. 
     A system for delivering a coated reconfigurable medical implant to a target site is also provided in an alternative embodiment of the present invention. A system in accord with this embodiment includes a carrier device and a medical implant covered in a protective membrane wherein the medical implant is located at the distal end of the carrier device on an implant carrying region. 
     A medical stent in accord with another embodiment is also provided. A stent in accord with this embodiment may include a metallic frame that may be expandable from a first position to a second position, a polymeric layer coating at least a portion of the metallic frame, and an encasing hollow deformable membrane surrounding the polymer layer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a coated workpiece that was manufactured without a protective membrane in place. 
     FIG. 2 is a side view of a coated workpiece that was manufactured in accord with an embodiment of the present invention. 
     FIG. 3 is a side view of a coated implant that has an encasing hollow deformable membrane surrounding it in accord with an alternative embodiment of the present invention. 
     FIG. 4 is a cross-sectional view taken along line IV—IV of FIG.  3 . 
     FIG. 5 is a side view of the coated implant of FIG. 3 after it has been reconfigured in accord with an alternative embodiment of the present invention. 
     FIG. 6 is a cross-sectional view taken along line VI—VI of FIG.  5 . 
     FIG. 7 is a side view of an uncrimped stent on a catheter prior to its insertion into an encasing hollow deformable membrane in accord with another alternative embodiment of the present invention. 
     FIG. 8 is a side view of the uncrimped stent of FIG. 7 after it has been inserted into the deformable membrane in accord with another alternative embodiment of the present invention. 
     FIG. 9 is a side view of the uncrimped stent of FIGS. 7-8 after the deformable membrane has been placed around it in accord with another alternative embodiment of the present invention. 
     FIG. 10 is a side view of the covered stent of FIGS. 7-9 prior to its insertion into a crimping chamber in accord with another alternative embodiment of the present invention. 
     FIG. 11 is a side view of a covered implant prior to its insertion into a braided sleeve in accord with another alternative embodiment of the present invention. 
     FIG. 12 is a side view of an implant prior to its insertion into an encasing hollow deformable membrane in accord with another alternative embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 is a side view of a coated workpiece  10  that was manufactured without the benefit of a protective membrane. As can been seen, the coating  12  of the workpiece haphazardly covers the workpiece  10  and in some areas  11  the workpiece  10  is not covered at all. The missing coating  12  from these removed areas  11  may have been errantly removed during various manufacturing steps and may have even been deposited on both the machinery and the personnel that handled the workpiece during these steps. 
     FIG. 2 is a side view of a coated workpiece  20  that was manufactured using a protective deformable membrane in accord with one embodiment of the present invention. As can be seen, the workpiece  20  has maintained most, if not all of its protective coating  21  with only a few depressions  22  evident on the workpiece&#39;s surface. With more of the coating  21  intact the workpiece  20  may be better suited to perform its desired function after its is deployed for its ultimate use. Moreover, by employing an encasing membrane to protect the coating  21  during the manufacture of the workpiece  20  the loads placed on the workpiece may be more evenly distributed across the coating  21  and the coating  21  may be less susceptible to contaminating everything that comes in contact with it. 
     FIG. 3 is a side view of a coated implant  35 , having a coating  32  that may be protected by an encasing membrane in accord with an alternative embodiment of the present invention. The coated implant  35  in this embodiment, which is comprised of the implant  30  defined by its frame  36 , may be covered with a coating  32  that is in turn surrounded by an encasing hollow deformable membrane  31 . This encasing deformable membrane  31  may be used to protect the coating  32  during the crimping of the implant  30 , during its other manufacturing steps, and during its subsequent handling. 
     During the crimping of an implant two goals are in conflict, high forces are desired to adequately secure the implant to the implant carrying region of a catheter or other carrier device while reduced forces are desired to prevent the smearing or removal of the coating on the implant  30 . By using a protective membrane  31  around the coating the damage caused by the compressive forces necessary to crimp the implant may be reduced. Moreover, by encasing a coated implant in a membrane  31  the smearing or other errant removal of the coating may be diminished by the presence of the membrane  31 . 
     In its resting state the deformable membrane  31  may have an inner diameter that is smaller than the outer diameter of the implant  30 . Consequently, the deformable membrane  31  in this embodiment should be enlarged in order to place the coated implant  30  into it. By having the deformable membrane  31  in a state of expansion while it encases the implant  30  the retroactive forces, to return the deformable membrane  31  to its original configuration, can help maintain the positioning of the membrane  31  on the implant  30  during its subsequent handling and use. Alternatively, in a different embodiment, rather than using pure compressive forces to retain the membrane around the implant  30 , the deformable membrane may be ribbed or folded or otherwise configured to facilitate its retention onto the implant  30 . 
     FIG. 4 is a cross-sectional view taken along line IV—IV of FIG.  3 . As can be seen, the encasing hollow deformable membrane  31  of the implant  30  is circular and completely encases the implant  30  and its coating  32 . The implant  30  in this configuration has not yet been crimped onto a catheter or other carrier device. 
     FIG. 5 is a side view of the implant  30  after it has been crimped. It is evident in FIG. 5 that the diameter of the implant  30  has been reduced during the crimping process. During this crimping process forces in the direction of arrows  51  have been exerted on the membrane  31  to reduce the diameter of the implant  30 . As is evident, the coating  32  has remained intact during this step. 
     FIG. 6 is a cross-sectional view taken along line VI—VI of FIG.  5 . When FIG. 6 is compared to FIG. 4 the reduction in diameter of the implant  30  is clearly evident. 
     FIG. 7 is a side view of a system that may be used in accord with an alternative embodiment of the present invention. In FIG. 7 the carrier device  74  may carry an implant  73  on an implant retention region near its distal end. This implant  73  may be held in place by sox  75  and may be coated with coating  79 . The implant  73  and the carrier device  74  may be stored within hypo-tube  76  and may be extended out of the hypo-tube  76  during the manufacturing process, as shown by arrow  77 , in order to place the membrane  72  around it. The encasing hollow deformable membrane  72  may be supported or stretched open by one end of an encasing cage  71 . This encasing cage  71  may be a wire cage sized to hold the membrane open, it may also be a clear tube or any other device adapted to hold the entrance orifice of the membrane  72  open during the manufacturing process. 
     During the manufacturing process, the carrier device  74  may be inserted into the entrance orifice of the membrane  72  such that the membrane  72  covers both sox  75  and the implant  73 . The membrane  72  may then be slid off of the cage  71  so that the membrane will completely encase the implant and the sox. Then, after the membrane  72  has been slid off of the cage  71 , the carrier device may be retracted from the cage  71 , now with its implant covered with the protective membrane  72 . 
     FIG. 8 is another side sectional view of the carrier device  74  and the encasing membrane  72  of the embodiment of FIG. 7, this time during the actual covering of the implant  73 . In this step, as described above, the hypo-tube  76  has been inserted into the opening of the encasing cage  71  and the encasing hollow deformable membrane  72 . Once the hypo-tube has been inserted into this opening a compressed fluid may be injected within a lumen  81  of the hypo-tube in order to inflate the membrane  72 . Then, once the membrane is inflated, the distal end of the carrier device  74  may be urged into the membrane  72 . The hypo-tube  76  may then be pulled away from the cage  71 , stopping the flow of compressed air into the membrane  72  and allowing the membrane to relax and encircle the implant  73 . The entrance orifice of the membrane  72  may also be released from the cage  71  at this point to allow the membrane to completely encircle the implant. 
     FIG. 9 shows a side view of the carrier device  74  after the membrane  72  has been released from the cage  71  as described above. As is evident in FIG. 9 the hypo-tube  76  is no longer inserted into the cage  71  and the implant  73  is now completely covered by the membrane  72 . This implant may now be removed from the case  71  and may be processed or handled in subsequent steps with the benefit of the protective membrane. 
     FIG. 10 shows a side view of the carrier device of FIGS. 7-9 after the implant has been covered and prior to its insertion into a crimping device  100 . This crimping device may be a hand held device or a mechanical device that may reduce the diameter of the implant  73  to more firmly secure it to the implant retention region located at the distal end of the carrier device  76 . Once the implant has been crimped, the membrane  72  may be removed immediately or it may remain on the implant  73  until just prior to its use by a practitioner. Alternatively, rather than behaving solely as a crimping mechanism, this device  100  may complete both steps by first applying the membrane and then crimping the implant. 
     FIG. 11 shows a side view of another alternative embodiment of the present invention. In this alternative embodiment an implant device  112  has an implant covered in a membrane  110  located at the device&#39;s  112  distal end. The membrane  110  in this embodiment is shaped like a sleeve and, therefore, has an exit orifice  113 . In this embodiment a supplemental cover, here a nylon braided sleeve  111 , may be placed over the membrane  110  to further protect the membrane during subsequent manufacturing and handling steps. 
     FIG. 12 is a side view of an implant  123  prior to its insertion into an encasing membrane  126  in accord with another alternative embodiment of the present invention. In this embodiment, rather than having compressed air injected through the hypo-tube, two nozzles  121  are positioned near the cage  125  entrance such that they may inject pressurized fluid into entrance orifice of the membrane  126  stretched open by the cage  125 . This cage  125  may also contain a brace  122  within it to prevent the membrane  126  from being over-inflated during the process. Therefore, in use, the membrane may be inflated by the nozzles to allow the implant  123  to be inserted into it. Once the implant has been inserted into the membrane, the membrane may then be slid off of the cage. The carrier device  124 , now carrying the implant, may, then, be removed from the cage  125  for subsequent use and handling. Alternatively, rather than injecting fluid to inflate the membrane, the nozzles may be situated behind the membrane and may be used to create a vacuum, thereby drawing the membrane into the cage to enlarge it. 
     In each of the above embodiments, once the workpiece is ready to be employed for its intended use, or at any other time deemed appropriate by the user, the protective membrane can be removed. The membrane may be removed by inflating or alternatively through some destructive method including a zip cord that will sever the membrane when it is pulled. 
     A protective membrane as employed in the various embodiments of the present invention can be manufactured from a number of materials, including latex, silicone, polyurethane, chloroprene or nitrile. It may also have a thickness preferably between 0.3 mm and 0.6 mm and contain materials that are flexible and allow for the transmission of forces to the workpiece during the workpiece&#39;s manufacture. In one embodiment, the membrane is a tube with a single opening while in another embodiment the membrane is a sleeve with openings on both ends. 
     The range of medical implants that may be protected by these membranes include: expandable and self-expanding stents, balloon catheters, vena-cava filters, aneurysm coils, stent-grafts, a-v shunts, anglo-catheters, and PICC&#39;s. Moreover, the coatings employed may contain paclitaxel as well as others therapeutics, which include, for example: pharmaceutically active compounds, proteins, cells, oligonucleotides, ribozymes, anti-sense oligonucleotides, DNA compacting agents, gene/vector systems (i.e., any vehicle that allows for the uptake and expression of nucleic acids), nucleic acids (including, for example, recombinant nucleic acids; naked DNA, cDNA, RNA; genomic DNA, cDNA or RNA in a non-infectious vector or in a viral vector and which further may have attached peptide targeting sequences; antisense nucleic acid (RNA or DNA); and DNA chimeras which include gene sequences and encoding for ferry proteins such as membrane translocating sequences (“MTS”) and herpes simplex virus-1 (“VP22”)), and viral, liposomes and cationic and anionic polymers and neutral polymers that are selected from a number of types depending on the desired application. Non-limiting examples of virus vectors or vectors derived from viral sources include adenoviral vectors, herpes simplex vectors, papilloma vectors, adeno-associated vectors, retroviral vectors, and the like. Non-limiting examples of biologically active solutes include anti-thrombogenic agents such as heparin, heparin derivatives, urokinase, and PPACK (dextrophenylalanine proline arginine chloromethylketone); antioxidants such as probucol and retinoic acid; angiogenic and anti-angiogenic agents and factors; agents blocking smooth muscle cell proliferation such as rapamycin, angiopeptin, and monoclonal antibodies capable of blocking smooth muscle cell proliferation; anti-inflammatory agents such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, acetyl salicylic acid, and mesalamine; calcium entry blocker such as verapamil, diltiazem and nifedipine; antineoplastic/antiproliferative/anti-mitotic agent such as paclitaxel, 5-fluorouracil, methotrexate, doxorubicin, daunorubicin, cyclosporine, cisplatin, vinbiastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors; antimicrobials such as triclosan, cephalosporins, aminoglycosides, and nitrofurantoin; anesthetic agents such as lidocaine, bupivacaine, and ropivacaine; nitric oxide (NO) donors such as linsidomine, molsidomine, L-airginine, NO-protein adducts, NO-carbohydrate adducts, polymeric or oligomeric NO adducts; anti-coagulants such as D-Phe-Pro-Arg chloromethyl ketone, an RGD peptide-containing compound, heparin, antithrombin compounds, platelet receptor antagonists, anti-thrombin antibodies, anti-platelet receptor antibodies, enoxaparin, hirudin, Warfarin sodium, Dicumarol, aspirin, prostaglandin inhibitors, platelet inhibitors and tick antiplatelet factors; vascular cell growth promotors such as growth factors, growth factor receptor antagonists, transcriptional activators, and translational promotors; vascular cell growth inhibitors such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors bifunctional molecules consisting of a growth factor and a cytotoxin, bifimctional molecules consisting of an antibody and a cytotoxin; cholesterol-lowering agents; vasodilating agents; agents which interfere with endogeneus vascoactive mechanisms; survival genes which protect against cell death, such as anti-apoptotic Bcl-2 family factors and Akt kinase; and combinations thereof. Cells can be of human origin (autologous or allogenic) or from an animal source (xenogeneic), genetically engineered if desired to deliver proteins of interest at the injection site. The delivery medium is formulated as needed to maintain cell function and viability. Any modifications are routinely made by one skilled in the art. 
     Polynucleotide sequences useful in practice of the invention include DNA or RNA sequences having a therapeutic effect after being taken up by a cell. Examples of therapeutic polynucleotides include anti-sense DNA and RNA; DNA coding for an antisense RNA; or DNA coding for tRNA or rRNA to replace defective or deficient endogenous molecules. The polynucleotides of the invention can also code for therapeutic proteins or polypeptides. A polypeptide is understood to be any translation product of a polynucleotide regardless of size, and whether glycosylated or not. Therapeutic proteins and polypeptides include as a primary example, those proteins or polypeptides that can compensate for defective or deficient species in an animal, or those that act through toxic effects to limit or remove harmful cells from the body. In addition, the polypeptides or proteins that can be injected, or whose DNA can be incorporated, include without limitation, antigenic factors and other molecules competent to induce angiogenesis, including acidic and basic fibroblast growth factors, vascular endothelial growth factor, hif-1, epidermal growth factor, transforming growth factor α and β, platelet-derived endothelial growth factor, platelet-derived growth factor, tumor necrosis factor α, hepatocyte growth factor and insulin like growth factor; growth factors; cell cycle inhibitors including CDK inhibitors; anti-restenosis agents, including p15, p16, p18, p19, p21, p27, p53, p57, Rb, nFkB and E2F decoys, thymidine kinase (“TK”) and combinations thereof and other agents useful for interfering with cell proliferation, including agents for treating malignancies; and combinations thereof. Still other useful factors, which can be provided as polypeptides or as DNA encoding these polypeptides, include monocyte chemoattractant protein (“MCP-1”), and the family of bone morphogenic proteins (“BMP&#39;s”). The known proteins include BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1), BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, BMP-15, and BMP-16. Currently preferred BMP&#39;s are any of BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 and BMP-7. These dimeric proteins can be provided as homodimers, heterodimers, or combinations thereof, alone or together with other molecules. Alternatively or, in addition, molecules capable of inducing an upstream or downstream effect of a BMP can be provided. Such molecules include any of the “hedgehog” proteins, or the DNA&#39;s encoding them. 
     These therapeutic agents can be used, for example, in any application for treating, preventing, or otherwise affecting the course of a disease or tissue or organ dysfunction. For example, the methods of the invention can be used to induce or inhibit angiogenesis, as desired, to prevent or treat restenosis, to treat a cardiomyopathy or other dysfunction of the heart, for treating Parkinson&#39;s disease or a stroke or other dysfunction of the brain, for treating cystic fibrosis or other dysfunction of the lung, for treating or inhibiting malignant cell proliferation, for treating any malignancy, and for inducing nerve, blood vessel or tissue regeneration in a particular tissue or organ. 
     While various embodiments of the present invention are disclosed above, other embodiments are also possible without straying from the spirit and scope of the present invention.