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Stent delivery system and deviceRelated Patent Categories: Prosthesis (i.e., Artificial Body Members), Parts Thereof, Or Aids And Accessories Therefor, Arterial Prosthesis (i.e., Blood Vessel), Stent Combined With Surgical Delivery System (e.g., Surgical Tools, Delivery Sheath, Etc.)Stent delivery system and device description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060287702, Stent delivery system and device. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD OF THE INVENTION [0001] The present invention relates generally to the field of implantable medical devices. More particularly, the invention relates to a stent delivery system and device having a coating, and a method for coating the same. BACKGROUND OF THE INVENTION [0002] Balloon angioplasty has been used for the treatment of narrowed and occluded blood vessels. A frequent complication associated with the procedure is restenosis, or vessel re-narrowing. Within 3-6 months of angioplasty, restenosis occurs in almost 50 percent of patients. In order to reduce the incidence of re-narrowing, several strategies have been developed. Implantable devices, such as stents, have been used to reduce the rate of angioplasty related restenosis by about half. The use of such devices has greatly improved the prognosis of these patients. Nevertheless, restenosis remains a formidable problem associated with the treatment of narrowed blood vessels. [0003] Restenosis associated with interventional procedures such as balloon angioplasty may occur by two mechanisms: thrombosis and intimal hyperplasia. During angioplasty, a balloon is inflated within an affected vessel thereby compressing the blockage and imparting a significant force, and subsequent trauma, upon the vessel wall. The natural antithrombogenic lining of the vessel lumen may become damaged thereby exposing thrombogenic cellular components, such as matrix proteins. The cellular components, along with the generally antithrombogenic nature of any implanted materials (e.g., a stent), may lead to the formation of a thrombus, or blood clot. The risk of thrombosis is generally greatest immediately after the angioplasty. [0004] The second mechanism of restenosis is intimal hyperplasia, or excessive tissue re-growth. The trauma imparted upon the vessel wall from the angioplasty is generally believed to be an important factor contributing to hyperplasia. This exuberant cellular growth may lead to vessel "scarring" and significant restenosis. The risk of hyperplasia associated restenosis is usually greatest 3 to 6 months after the procedure. [0005] Prosthetic devices, such as stents or grafts, may be implanted during interventional procedures such as balloon angioplasty to reduce the incidence of vessel restenosis. To improve device effectiveness, stents may be coated with one or more therapeutic agents providing a mode of localized drug delivery. The therapeutic agents are typically intended to limit or prevent the aforementioned mechanisms of restenosis. For example, antithrombogenic agents such as heparin or clotting cascade IIb/IIIa inhibitors (e.g., abciximab and eptifibatide) may be coated on the stent thereby diminishing thrombus formation. Such agents may effectively limit clot formation at or near the implanted device. Some antithrombogenic agents, however, may not be effective against intimal hyperplasia. Therefore, the stent may also be coated with antiproliferative agents or other compounds to reduce excessive endothelial re-growth. Therapeutic agents provided as coatings on implantable medical devices may effectively limit restenosis and reduce the need for repeated treatments. [0006] Several considerations should be made when devising a strategy for coating implantable prosthetic devices, such as stents or grafts. One consideration in coating strategy relates to surface uniformity. Ideally, coatings should be evenly applied with limited surface imperfections. Some coating strategies, however, may produce pooling of the coating material and/or dry spots. Failure to control surface uniformity may lead to inaccurate, non-uniform drug dose delivery and therapeutic variability from device to device. Therefore, it would be desirable to provide a uniform stent coating. [0007] Another consideration in coating strategy relates to topography. It may be desirable for the coating to be disposed on certain areas of the stent. For example, stents typically have a wire mesh with open spaces formed between. Some coating strategies may leave `bridged` material within the open spaces. Such coating bridges may break off causing complications or may prevent the device from expanding or functioning properly. As another example, only certain portions of the stent may require coating, or several coating layers may be required. As such, it would be desirable to control the stent coating topography. [0008] Another consideration in coating strategy relates to efficiency. It may be desirable to effectively coat the implantable device in relatively short time, with a minimal amount of coating material. Some coating strategies require lengthy steps, thereby reducing the amount of devices that can be coating within a certain period. In addition, some strategies do not utilize coating material in a complete manner thereby increasing cost. For example, coating material that is vaporized may get dispersed on areas other than the stent surface. Therefore, it would be desirable to efficiently coat the stent. [0009] Accordingly, it would be desirable to provide a strategy for coating a stent that would overcome the aforementioned and other disadvantages. SUMMARY OF THE INVENTION [0010] One aspect of the present invention provides a stent delivery system. The system includes a catheter, a balloon operably attached to the catheter, and a stent disposed on the balloon. The stent includes at least one coating applied by dipping a portion of the stent into a coating liquid while simultaneously rotating the stent. The coating may include a therapeutic agent and may be substantially on an outer surface of the stent. The coating may be about 1 to 150 microns thick. The stent may be dipped at a rate of about 0.1 to 25.0 millimeters per second, and for a time period of about 5 seconds to 10 minutes. The stent may be rotated at a rate of about 100 to 25,000 rotations per minute. The system may further include a control sequence, and a programmable logic chip. The logic chip may control at least one of the dipping and rotation of the stent based on the control sequence. [0011] Another aspect of the invention provides a stent device. The stent device includes a body, and at least one coating rotationally applied to a portion of the body, while the body is at least partially immersed in a coating liquid. The coating may include a therapeutic agent and may be substantially on an outer surface of the body. The coating may be about 1 to 150 microns thick. The body may be dipped at a rate of about 0.1 to 25.0 millimeters per second, and for a time period of about 5 seconds to 10 minutes. The body may be rotated at a rate of about 100 to 25,000 rotations per minute. The device may further include a control sequence, and a programmable logic chip. The logic chip may control the rotational application based on the control sequence. [0012] Another aspect of the invention provides a method for coating a stent. The method includes immersing a portion of the stent into a coating liquid, and withdrawing the immersed portion of the stent from the coating liquid. The method further includes simultaneously rotating the stent with respect to the coating liquid while the stent is being immersed and withdrawn. The rotation may force the coating liquid to an outer portion of the stent. Multiple layered coatings may be applied. Immersing the stent may include controlling a stent wetting characteristic. The stent may be immersed at a rate of about 0.1 to 25.0 millimeters per second, and for a time period of about 5 seconds to 10 minutes. The stent may be rotated at a rate of about 100 to 3,500 rotations per minute during immersion. Withdrawing the stent may include controlling a stent coating thickness, wherein the coating may be about 1 to 150 microns thick. The stent may be withdrawn at a rate of about 0.1 to 25.0 millimeters per second, and rotated at a rate of about 600 to 25,000 rotations per minute. The method may further include programming a control sequence, and controlling at least one of the immersion, withdrawal, and rotation based on the control sequence. [0013] Another aspect of the invention provides a stent device. The stent devices includes means for immersing a portion of the stent into a coating liquid, and means for withdrawing the immersed portion of the stent from the coating liquid. The stent device further includes means for simultaneously rotating the stent with respect to the coating liquid while the stent is being immersed and withdrawn. The stent device may further include a control sequence, and means for controlling at least one of the immersion, withdrawal, and rotation based on the control sequence. [0014] The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention, rather than limiting the scope of the invention being defined by the appended claims and equivalents thereof. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a perspective view of a stent delivery system made in accordance with the present invention; [0016] FIG. 2 is a perspective view of a prior art stent compatible with the disclosed coating process of the present invention; [0017] FIG. 3 is a magnified view of two W-shaped elements of the stent in FIG. 2; and [0018] FIG. 4 is diagram of a stent coating process made in accordance with the present invention. DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS [0019] Referring to the drawings, wherein like reference numerals refer to like elements, FIG. 1 is a perspective view of a stent delivery system made in accordance with the present invention and shown generally by numeral 100. The stent delivery system 100 includes a catheter 105, a balloon 110 operably attached to the catheter 105, and a stent 120 disposed on the balloon 110. The balloon 110, shown in a collapsed state, may be any variety of balloons capable of expanding the stent 120. The balloon 110 may be manufactured from any sufficiently elastic material such as polyethylene, polyethylene terephthalate (PET), nylon, or the like. In one embodiment, the balloon 110 may include retention means 111, such as mechanical or adhesive structures, for retaining the stent 120 until it is deployed. The catheter 105 may be any variety of balloon catheters, such as a PTCA balloon catheter, capable of supporting a balloon during angioplasty. Continue reading about Stent delivery system and device... Full patent description for Stent delivery system and device Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Stent delivery system and device patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Stent delivery system and device or other areas of interest. ### Previous Patent Application: Retrievable device having a reticulation portion with staggered struts Next Patent Application: Iliac artery stent graft Industry Class: Prosthesis (i.e., artificial body members), parts thereof, or aids and accessories therefor ### FreshPatents.com Support Thank you for viewing the Stent delivery system and device patent info. IP-related news and info Results in 0.09493 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers 174 |
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