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Endoluminal expansion systemRelated 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.), Expandable Stent With Constraining MeansEndoluminal expansion system description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060190071, Endoluminal expansion system. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of application Ser. No. 10/201,172, filed Jul. 22, 2002. FIELD OF THE INVENTION [0002] The present invention relates to the transcatheter delivery and remote deployment of implantable medical devices and more particularly to a system for the expansion and deployment of endoprostheses. BACKGROUND OF THE INVENTION [0003] Endoluminal therapies typically involve the insertion of a delivery catheter that transports an implantable prosthetic device into a body conduit through a small, often percutaneous, remote access site. Once access to the body conduit is achieved, the delivery catheter is used to mediate intraluminal delivery and subsequent deployment of the prosthesis via one of several techniques. In this fashion, the prosthesis can be remotely implanted to achieve a therapeutic outcome. In contrast to conventional surgical therapies, endoluminal treatments are distinguished by their "minimally invasive" nature. [0004] Self-expanding endoprostheses are generally comprised of a stent component with or without a graft covering over the stent interstices. They are designed to spontaneous dilate (i.e., elastically recover) from their delivery diameter, through a range of intermediary diameters, up to a maximal, pre-determined functional diameter. The endoluminal delivery and deployment of self-expanding endoprostheses pose several unique problems. First, the endoprosthesis itself must be radially compacted to a suitable introductory size (or delivery diameter) to allow insertion into the vasculature, then it must be constrained in that compacted state and mounted onto a delivery device such as a catheter shaft. Subsequently, the constraint must be removed in order to allow the endoprosthesis to expand to its functional diameter and achieve the desired therapeutic outcome. Preferably, the means of constraint will not adversely affect the delivery catheter performance (e.g., detracting from the flexibility of the delivery system) or add significantly to introductory profile. The constraint must also incorporate some type of release mechanism or scheme that can be remotely actuated by the implanting clinician. Consequently, deployment methodologies that are consistent with conventional interventional practices are preferred. [0005] Delivery mechanisms for self-expanding endoprostheses of the prior art may be generally classified into one of two general categories, either coaxial sheaths or fiber-based constraints. Delivery systems also exist that use both of these types of mechanisms in combination. [0006] Tubular coaxial sheaths are one approach used to constrain the compacted self-expanding endoprosthesis. Normally, these coaxial sheaths extend over the entire length of an inner delivery catheter onto which the endoprosthesis is mounted near the catheter tip (i.e., leading end). Deployment is typically initiated by pulling on a handle or knob located near the hub (i.e., trailing end) of the catheter, which retracts the constraining sheath and allows the device to expand. During this procedure, the clinician maintains the position of the device by holding the inner (delivery) catheter in a stationary position. Existing problems and/or complications with the tubular coaxial sheath type of delivery system include friction between compacted device and constraining sheath, friction between the constraining sheath and delivery catheter, and friction between the delivery catheter and constraining sheath hemostasis valve, all of which can hinder deployment accuracy, speed and control. Additionally, a tubular coaxial constraining sheath can also reduce flexibility and add introductory profile due to the thickness of the constraining sheath. [0007] In the fiber-based delivery systems, the self-expanding endoprosthesis is constrained in the delivery profile by one or more removable fibrous strands, with or without an additional implantable constraint element. The endoprosthesis is released from its compacted state through tension applied to a deployment "cord" that normally runs through an additional lumen within the delivery catheter. Typically, applying tension to the deployment cord initiates the release of the fiber constraint by, for example, unlacing linear slip knots (see Lau, et al., U.S. Pat. No. 5,919,225), removing circumferential croquet knots (e.g., Strecker, U.S. Pat. No. 5,405,378), or detaching the interlocking loops of a warp-knitted constraint (e.g., Armstrong et al., U.S. Pat. No. 6,224,627). Other fiber-based delivery systems are described by Lindemann, U.S. Pat. No. 4,878,906, and Hillstead, U.S. Pat. No. 5,019,085. [0008] Another variant of the fiber-based delivery systems is the mechanism employed in the EXCLUDER.RTM. endoprosthesis marketed by W.L. Gore and Associates, Inc (Flagstaff, Ariz.). This mechanism entails a "chain-stitch" sewn into the seam of a biocompatible constraining tube that contains the compacted endoprosthesis. Applying tension to the fibrous constraint in this mechanism allows the seam in the biocompatible constraining tube to be open, and the self-expanding endoprosthesis to deploy. The biocompatible constraining tube is implanted along with the endoprosthesis, trapped between the abluminal surface of the device and the wall of the host vessel. See WO98/27894. [0009] Problems with fiber-based type of delivery systems include possible premature deployment during introduction to the vascular system through hemostasis valves, extra lumens required on the delivery catheter which can increase profile, possible snagging of fiber(s) on the compacted implantable device, the possibility of emboli resulting from moving lines between the catheter and the blood vessel, and possible breakage of the deployment cord itself. [0010] U.S. Pat. Nos. 5,755,769 and 6,019,787 to Richard et al. teach another constraining sheath around a self-expanding stent. The sheath is cut longitudinally into several segments by cutting wires or fibers actuated by pulling a handle at the opposite end of the delivery system. The sheath is attached to or integral to the delivery catheter with the result that the segments are removed with the catheter following stent deployment. No catheter balloon or other means for exerting a circumferential disrupting force to the sheath is suggested, nor are materials appropriate for the sheath suggested. This design requires lines to run over the length of the catheter. [0011] U.S. Pat. No. 6,086,610 to Duerig et al. teaches a self-expanding stent provided with a tubular constraining sheath that is plastically deformable by a circumferential distending force such as a catheter balloon. This sheath remains implanted with the stent following deployment and fully covers the entire circumference of the stent in the fashion of a conventional stent covering, i.e., the tubular sheath is not disrupted. The Duerig et al. device is delivered from a conventional balloon catheter, but thought to have limitations, including radial recoil of the sheath after the balloon is pressurized and deflated, which can compromise luminal gain. Further, the presence of the cover may adversely affect the ability of the stent to fully deploy, and the balloon length must be equal to or longer than the stent, and this long balloon can potentially damage the vessel. SUMMARY OF THE INVENTION [0012] The present invention relates to an endoprosthesis expansion system comprising, in combination, a delivery component such as a length of catheter tubing having at its distal end an intermediate sheath component, and an inner elongate actuation member that is preferably an inner tube located within the full length of the delivery catheter and intermediate sheath component. The inner elongate actuation member (e.g., inner tube) has a protrusion affixed to its distal end, and an expandable endoprosthesis is fitted in a compacted state about the intermediate sheath, proximal to the protrusion. If the endoprosthesis is a self-expanding endoprosthesis (as is preferred), an exterior constraining sheath is required around the outer surface of the endoprosthesis to contain the endoprosthesis in a compacted configuration. Following insertion of the endoprosthesis and delivery system into a body conduit (such as a blood vessel) and transport of the endoprosthesis to the desired site within the body conduit, the endoprosthesis is deployed by axially moving the protrusion through the system, thereby applying a radially directed outward force and causing simultaneous dilatation of the intermediate sheath and disruption of the exterior constraining sheath. Alternatively, axial movement of the elongate actuation member against the end of the intermediate sheath, applying axial compression to the intermediate sheath, may cause the intermediate sheath to shorten and simultaneously increase in diameter, thereby initiating expansion and deployment of the endoprosthesis. Disruption of the exterior constraining sheath, in the case of a self-expanding prosthesis, releases the stored energy in the formerly constrained prosthesis, allowing it to spontaneously expand and accomplish full deployment against the luminal surface of the body conduit at the desired site. [0013] The exterior constraining sheath is preferably made of an implantable material and may be left captured between the endoprosthesis and the luminal surface of the body conduit. Alternatively, the exterior constraining sheath may be secured to the adjacent delivery catheter and withdrawn from between the endoprosthesis and the wall of the body conduit when the delivery catheter is withdrawn. [0014] If a non-self-expanding endoprosthesis is used (e.g., a balloon-expandable stent), diametrical expansion may be accomplished by moving the protrusion axially through the stent, thereby enlarging the diameter by plastically deforming the stent. Likewise, as described with the self-expanding stent embodiment, the application of axial compression against one end of the intermediate sheath by the protrusion can cause an increase in the diameter of the intermediate sheath, forcing a corresponding diametrical increase in the balloon expandable stent. [0015] In addition to stent devices, the endoprostheses utilized with the present invention may also be stent-grafts. The phrase "stent-graft" is used herein to describe a stent provided with a covering, typically of a vascular graft material such as porous expanded polytetrafluoroethylene (ePTFE) or polyethylene terephthalate (PET). The covering may be provided over either or both of the inner and outer surfaces of the stent. The covering may cover a portion of the otherwise open stent interstices or it may cover all of the stent interstices. [0016] While the system of the present invention is intended primarily for stents and stent-grafts for use in vascular repairs, it is also useful for expandable devices for other applications in other body conduits, e.g., esophageal or biliary duct repairs. [0017] While a protrusion can be used to initiate deployment without an intermediate sheath inside the endoprosthesis, the use of the intermediate sheath, made from a thin, strong and lubricious material, prevents the protrusion from damaging the endoprosthesis (particularly if the endoprosthesis is a stent-graft with a covering on the luminal surface). It also reduces the likelihood of "bunching" of the endoprosthesis due to the application of an axial force. It can likewise reduce the amount of axial force required as well as reducing the variability of the axial force (as the protrusion moves along the internal length of the endoprosthesis), by providing a uniform compression resistance against the protrusion as opposed to the variable resistance provided by the wire surface of the interior of an endoprosthesis. [0018] Both the exterior constraining sheath and the intermediate sheath may be made to be dilatable or disruptable by various and similar means. For the exterior constraining sheath, it is preferred to provide a line of perforations partially or entirely through the wall of the tubular constraining sheath, parallel to the longitudinal axis of the tubular constraining sheath. The constraining sheath may be caused to disrupt by splitting along this line of perforations, upon the application of an outwardly directed radial force from within the sheath (and within the contained endoprosthesis). [0019] For the intermediate sheath located within the endoprosthesis, it is preferred that it is of a substantially tubular form and is dilatable via one or more, equally radially-spaced apart splits are used along the length of that sheath. Alternatively, the intermediate sheath may be elastically or plastically deformable by the protrusion. In other alternatives, the intermediate sheath may be caused to be split, ripped, torn or otherwise changed in proportion by the movement of the protrusion against and/or through the intermediate sheath. Any of these mechanisms are considered to constitute dilatation of the intermediate sheath. It is apparent that the tubular form of the intermediate sheath includes various embodiments and as such is considered to be a substantially tubular sheath. [0020] The present invention also provides a means of controlling the radial dynamics of device deployment. For example, the present invention can be configured to `pop` open to allow rapid device deployment, or alternatively to undergo more gradual, controlled, stepwise release during device deployment, or a combination of both. Continue reading about Endoluminal expansion system... Full patent description for Endoluminal expansion system Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Endoluminal expansion system 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. 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