The assignee for this patent application is
Reporters obtained the following quote from the background information supplied by the inventors: "This invention generally relates to a stent for treating a disorder with a drug over a period of time extending beyond biodegradation of the stent scaffolding.
"In particular, the invention relates to radially expandable endoprostheses that are adapted to be implanted in a body lumen. An 'endoprosthesis' corresponds to an artificial device that is placed inside the body. A 'lumen' refers to a cavity of a tubular organ such as a body lumen. A stent is an example of such an endoprosthesis. Stents are generally cylindrically shaped devices which function to hold open and sometimes expand a segment of a body lumen or other anatomical lumen such as urinary tracts and bile ducts. Stents are often used in the treatment of atherosclerotic stenosis in body lumens. 'Stenosis' refers to a narrowing or constriction of the diameter of a bodily passage or orifice. In such treatments, stents reinforce body vessels and prevent restenosis following angioplasty. 'Restenosis' refers to the reoccurrence of stenosis in a body lumen or heart valve after it has been subjected to angioplasty or valvuloplasty.
"The treatment of a diseased site or lesion with a stent involves both delivery and deployment of the stent. 'Delivery' refers to introducing and transporting the stent through a body lumen to the treatment area in a body lumen. 'Deployment' corresponds to the expanding of the stent within the lumen at the treatment area. Delivery and deployment of a stent are accomplished by positioning the stent at one end of a catheter, inserting the end of the catheter through the skin into a body lumen, advancing the catheter in the body lumen to a desired treatment location, expanding the stent at the treatment location, and removing the catheter from the lumen. In the case of a balloon expandable stent, the stent is mounted about a balloon disposed on the catheter. Mounting the stent typically involves compressing or crimping the stent onto the balloon. The stent is then expanded by inflating the balloon. The balloon may then be deflated and the catheter withdrawn. In the case of a self-expanding stent, the stent may be secured to the catheter via a retractable sheath or a sock.
"When the stent is in a desired bodily location, the sheath may be withdrawn allowing the stent to self-expand. This requires a sufficient degree of strength and rigidity or stiffness. In addition to having adequate radial strength, the stent should be longitudinally flexible to allow it to be maneuvered through a tortuous vascular path.
"Thus, a stent is typically composed of a scaffolding that includes a pattern or network of interconnecting structural elements or struts. The scaffolding can be formed of tubes, or sheets of material rolled into a cylindrical shape. The scaffolding is designed to allow the stent to be radially expandable. The pattern is generally designed to maintain the longitudinal flexibility and radial rigidity required of the stent. Longitudinal flexibility facilitates delivery of the stent and radial rigidity is needed to hold open a body lumen. A medicated stent may be fabricated by coating the surface of either a metallic or polymeric scaffolding with a polymeric carrier that includes a bioactive agent. The polymeric scaffolding may also serve as a carrier of bioactive agent.
"In many treatment applications of stents, the presence of a stent in a body may be necessary for a limited period of time until its intended function of, for example, maintaining vascular patency and/or drug delivery is accomplished. Thus, stents are often fabricated from biodegradable, bioabsorbable, and/or bioerodable materials such that they completely erode only after the clinical need for them has ended. In addition, a stent should also be capable of satisfying the mechanical requirements discussed above during the desired treatment time.
"A polymeric stent should be mechanically stable throughout the range of stress experienced during use. In addition to mechanical stability, a stent should have a sufficient rate of biodegradability or erosion as dictated by a treatment regimen. However, one of the major clinical challenges of bioabsorbable stents is adequately suppressing inflammatory responses triggered by the degradation of the stent. The embodiments of the invention address this and other concerns."
In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "Disclosed is a stent comprising a bioabsorbable polymeric scaffolding; and a plurality of depots in at least a portion of the scaffolding, wherein the plurality of depots comprise a bioabsorbable material, 'wherein the degradation rate of all or substantially all of the bioabsorbable polymer of the scaffolding is faster than the degradation rate of all or substantially all of the bioabsorbable material of the depots.
"Also disclosed is a method treating a body lumen, the method comprising providing a stent comprising a scaffolding having a plurality of depots, wherein the scaffolding degrades at a faster rate than a material in the plurality of depots and deploying the stent at a treatment area in a body lumen.
"Also disclosed is a method of treating a body lumen, the method comprising deploying a first stent at a treatment area, wherein the first stent includes a bioabsorbable polymeric scaffolding and a plurality of depots in at least a portion of the scaffolding, wherein the depots have a bioabsorbable material, and wherein the degradation rate of all or substantially all of the bioabsorbable polymer of the scaffolding is faster than the degradation rate of all or substantially all of the bioabsorbable material in the depots and deploying a second stent in at least a portion of the treatment area.
BRIEF DESCRIPTION OF THE FIGURES
"FIG. 1 depicts a stent.
"FIG. 2(a) depicts a cross-section of a stent implanted in a body lumen, the stent having a scaffolding and a drug coating.
"FIG. 2(b) depicts the stent of FIG. 2(a) after endothelialization of the stent in the body lumen.
"FIG. 2© depicts the stent of FIG. 2(a) after endothelialization of the stent and degradation of the scaffolding, where the drug coating of the stent remains lodged in the lumen and continues to deliver drug in the lumen.
"FIG. 3 depicts a second stent that is implanted at a treatment area of a first stent, where the scaffolding (not depicted) of the first stent has degraded but the coating of the first stent remains lodged in the lumen wall.
"FIG. 4(a) depicts a cross section of a stent implanted in a body lumen, the stent having a scaffolding and depots.
"FIG. 4(b) depicts the stent of FIG. 4(a) after endothelialization of the stent in the body lumen.
"FIG. 4© depicts the stent of FIG. 4(a) after endothelialization of the stent and degradation of the scaffolding.
"FIG. 5 depicts a second stent that is implanted at a treatment area of the first stent, where the scaffolding (not depicted) of the first stent has degraded."
For more information, see this patent application: Gale,
Keywords for this news article include: Surgery, Angiology, Treatment, Cardiology, Restenosis, Angioplasty, Heart Disease, Risk and Prevention, Surgical Technology, Vascular Surgical Procedures,
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