CATHETER WITH REMOVABLE BALLOON PROTECTOR AND STENT DELIVERY SYSTEM WITH REMOVABLE STENT PROTECTOR

Abstract: A balloon catheter is provided having an expandable distal portion and balloon protector means comprising a first removable sleeve having a variable inner diameter to ease sliding the first sleeve over the balloon, and an optional second removable (outer) sleeve positioned over the inner sleeve, the second (outer) sleeve having a constrictive relationship with the first (inner) sleeve, said first and second sleeves being removed prior to use of the catheter. A stent delivery system includes a catheter having an expandable distal portion, said distal portion further comprising a balloon and at least one dam over which the balloon extends, and a stent positioned around the distal portion of the catheter around the balloon; a first removable (inner) sleeve in the region of the distal portion of the catheter positioned around the stent, said first sleeve comprising a variable inner diameter to ease sliding the sleeve over the balloon and stent; an optional second removable (outer) sleeve positioned over the stent, first sleeve and at least one dam, said second (outer) sleeve having a constrictive relationship with the first (inner) sleeve, said first and second sleeves being removed prior to use of the stent delivery system and release of the stent by expansion of the balloon.

Description: CATHETER WITH REMOVABLE BALLOON PROTECTOR AND STENT DELIVERY SYSTEM WITH REMOVABLE STENT PROTECTOR Cross Reference to Related Applications This application is a Continuation-in-part of U.S. Patent Application Serial Number 08/812,351 filed March 5, 1997, incorporated herein by reference. Background of the Invention Field of the Invention The present invention relates generally to catheters having an expandable balloon and to premounted balloon expandable stent balloon catheters, and specifically to a dilatation balloon catheter with a balloon protector means or a stent delivery system with a balloon and stent protector means. Description of Related Art Percutaneous transluminal coronary angioplasty (PTC A) is a procedure which is well established for the treatment of blockages in the coronary arteries. Blockages may occur from cholesterol precipitation on the coronary wall which may be in any stage from initial deposit through aged lesions. Coronary arteries may also become blocked due to formation of thrombus. The most widely used form of percutaneous coronary angioplasty makes use of a dilatation balloon catheter. In typical PTC A procedures, the cardiovascular system of a patient is accessed with an introducer, usually in the groin area. All other devices including a guiding catheter are percutaneously introduced into the cardiovascular system of a patient through the introducer and advanced through a vessel until the distal end thereof is at a desired location in the vasculature. A guide wire and a dilatation catheter having a balloon on the distal end thereof are introduced through the guiding catheter with the guide wire sliding through the dilatation catheter. The guide wire is first advanced out of the guiding catheter into the patient's coronary vasculature and the dilatation catheter is advanced over the previously advanced guide wire until the dilatation balloon is properly positioned across the lesion. Once in position across the lesion, the flexible, expandable, preformed balloon is inflated to a predetermined size with a fluid at relatively high pressures, such as greater than about four atmospheres, to radially compress the atherosclerotic plaque of the lesion against the inside of the artery wall and thereby dilate the lumen of the artery. The balloon is then deflated to a small profile so that the dilatation catheter may be withdrawn from the patients vasculature and blood flow resumed through the dilated artery. In angioplasty procedures of the kind described above, there may be restenosis of the artery, which either necessitates another angioplasty procedure, a surgical by-pass operation, or some method of repairing or strengthening the area. To reduce restenosis and strengthen the area, a physician can implant an intravascular prosthesis for maintaining vascular patency, called a stent, inside the artery at the lesion. In general, stents are prosthetic devices which can be positioned within a body cavity, for example, a blood vessel of the body of a living human or in some other difficulty accessible place. A stent generally has a diameter which may be increased or decreased. Stents are particularly useful for permanently widening a vessel which is in a narrowed state, or for internally supporting a vessel damaged by an aneurysm. Such stents are typically introduced into the body cavity by use of a catheter. The catheter is usually of the balloon catheter type in which the balloon is utilized to expand the stent, which is positioned over the balloon, to place it in a selected location in the body cavity. The stent is expanded to a larger diameter for placement in the vasculature, often by the balloon portion of the catheter. Stents delivered to a restricted coronary artery, expanded to a larger diameter by a balloon catheter, and left in place in the artery at the site of a dilated lesion are shown in U.S. Patent 4,740,207 to Kreamer and U.S. Patent 5,007,926 to Derbyshire. One important characteristic of a dilatation balloon catheter is its "profile", which is determined by the outer diameter (O.D.) of the distal end portion of the balloon and stent when deflated. The outer diameter affects the ease and ability of the dilatation catheter to pass through a guide catheter, through the coronary arteries, and across a tight lesion. Considerable effort has been made in developing low profile dilatation balloon catheters. U.S. Patent No. 5,342,307, incorporated herein by reference, discloses a balloon protector sleeve used with a tri-fold dilatation balloon catheter for angioplasty. Minimization of "profile" is of importance in balloon catheters and stent delivery systems. Accordingly, the present invention is particularly directed to improved arrangements of balloon catheters having a balloon protector and stent delivery systems having a balloon and including a stent protector means which provide a minimized profile. Summary of the Invention This invention concerns medical devices such as balloon catheters and apparatus suitable for delivery of stents to body cavities. The present invention is particularly directed to improved balloon protectors for use with balloon catheters and to improved arrangements for stent delivery systems, the improvements comprising stent protector means. Accordingly, the present invention provides a catheter having an expandable distal portion constructed and arranged for expanding the outer diameter of the catheter from a contracted state to an expanded state. The distal portion of the catheter comprises a balloon which is folded or otherwise collapsed, and is expandable to an expanded condition. The balloon protector may comprise removable first and second sleeves. The first removable (inner) sleeve is positioned around the balloon, the inner sleeve being made of a lubricious material and further comprising a first end, a second end and a slit extending therethrough. The slit may extend from end to end. Alternatively, the slit may extend along a predetermined length of the sleeve, the rest of the length of the sleeve comprising a continuous tube. The slit provides a variable inner diameter to ease sliding the sleeve over the balloon. The second removable (outer) sleeve is positioned over the first (inner) sleeve, the outer sleeve having a constrictive relationship with the inner sleeve. The outer sleeve thereby provides an additional compressive force to reduce the profile of the constricted balloon. For example, the outer sleeve may have an inner diameter less than the outer diameter of the inner sleeve, whereby when compressed by the outer sleeve, the inner sleeve will have an inner diameter approximately equal to or greater than the profile of the balloon in its contracted state. The inner and outer sleeves are removed prior to use of the catheter. Alternatively, the balloon protector means may comprise a single compressive sleeve. This single compressive sleeve may be of any configuration described herein. A preferred embodiment of the single sleeve has a slit along the length thereof. Another preferred embodiment of the single sleeve has a helical slit along a predetermined length of the sleeve, defining a spiral cut region and a continuous tubular region. Yet another preferred embodiment has a spiral cut region and a continuous tubular region, the continuous tubular region comprising a dimpled region and a straight tubular region. The dimples may be round-like, spiral, triangular, oval, oblong, circular (like tire treads) around the circumference or at an angle around the circumference, or combinations thereof. The dimples may also be of any other suitable configuration. In another alternative embodiment, the single sleeve may comprise a dimpled region extending along part of the single sleeve or the entire sleeve. The present invention also provides a catheter having an expandable distal portion constructed and arranged for expanding the outer diameter of the catheter from a contracted state to an expanded state. The distal portion of the catheter may further comprise one or two dams (also referred to as enlarged portions, stops, bumpers, longitudinal motion preventers, or the like) and a balloon. The balloon is folded or otherwise collapsed, and is expandable to an expanded condition. The catheter further comprises a balloon protector means comprising removable first and second sleeves. The first removable (inner) sleeve is positioned over the balloon and between the dams (where two dams are present), the inner sleeve being made of a lubricious material and further comprising a first end, a second end and a slit extending therethrough. The slit may extend from end to end. Alternatively, the slit may extend along a predetermined length of the sleeve, the rest of the length of the sleeve comprising a continuous tube. The continuous tube may further comprise a dimpled region and a straight tubular region. The slit provides a variable inner diameter to ease sliding the sleeve over the balloon. The second removable (outer) sleeve is positioned over the first sleeve and dams, the outer sleeve having a constrictive relationship with the inner sleeve. The outer sleeve thereby provides an additional compressive force to reduce the profile of the collapsed balloon. For example, the outer sleeve may have an inner diameter less than the outer diameter of the inner sleeve, whereby when compressed by the outer sleeve, the inner sleeve will have an inner diameter approximately equal to or less than the outer profile of the collapsed balloon over the dam(s). The inner and outer sleeves are removed prior to use of the catheter. Alternatively, the balloon protector may comprise a single compressive sleeve. This single compressive sleeve may be of any configuration described herein. A preferred embodiment of the single sleeve has a slit along the length thereof. Another preferred embodiment of the single sleeve has a helical slit along a predetermined length of the sleeve, defining a spiral cut region and a continuous tubular region. Yet another preferred embodiment has a spiral cut region and a continuous tubular region, the continuous tubular region comprising a dimpled region and a straight tubular region. The dimples may be round-like, spiral, triangular, oblong, longitudinal, circular (like tire treads) around the circumference or at an angle to the circumference, or combinations thereof. The dimples may also be of any other suitable configuration. In another alternative embodiment, the single sleeve may comprise a dimpled region extending along part of the single sleeve or the entire sleeve. The present invention also provides a stent delivery system including a catheter having an expandable distal portion constructed and arranged for expanding the outer diameter of the catheter from a contracted state to an expanded state. The distal portion of the catheter may further comprise one or two dams (also referred to as enlarged portions, stops, bumpers, longitudinal motion preventers, or the like) and a balloon. A stent is positioned around the distal portion of the catheter. Where there is a single dam, the stent may be positioned either proximally or distally of the dam. In an embodiment having a single proximal dam, the stent is positioned distally of the proximal dam. In an embodiment having a single distal dam, the stent is positioned proximally of the distal dam. Where two spaced dams are present, the stent is positioned between the dams, i.e. distally of the proximal dam and proximally of the distal dam. The stent has a contracted condition, being sized in the contracted condition to closely surround the balloon (the balloon in such instance being folded or otherwise collapsed), and being expandable to an expanded condition. The stent delivery system further comprises a stent protector means comprising removable first and second sleeves. The first removable (inner) sleeve is positioned around the stent and between the dams, the inner sleeve being made of a lubricious material and further comprising a first end, a second end and an expansion slit extending therethrough. The slit may extend from end to end. Alternatively, the slit may extend along a predetermined length of the sleeve, the rest of the length of the sleeve comprising a continuous tube. The continuous tube may further comprise a dimpled region and a straight tubular region. The slit provides a variable inner diameter to ease sliding the sleeve over the balloon and stent. The second removable (outer) sleeve is positioned over the stent, first sleeve and dams, the outer sleeve having a constrictive relationship with the inner sleeve. The outer sleeve thereby provides an additional compressive force to reduce the profile of the stent and collapsed balloon. For example, the outer sleeve may have an inner diameter less than the outer diameter of the inner sleeve, whereby when compressed by the outer sleeve, the inner sleeve will have an inner diameter approximately equal to or less than the outer profile of the collapsed balloon over the dam(s). The stent protector means provides reduction of the profile of the compressed stent over the collapsed balloon. Alternatively, the stent protector means may comprise a single compressive sleeve. This single compressive sleeve may be of any configuration described herein. A preferred embodiment of the single sleeve has a slit along the length thereof. Another preferred embodiment of the single sleeve has a helical slit along a predetermined length of the sleeve, defining a spiral cut region and a continuous tubular region. Yet another preferred embodiment has a spiral cut region and a continuous tubular region, the continuous tubular region comprising a dimpled region and a straight tubular region. The dimples may be round-like, spiral, triangular, oblong, longitudinal, circular (like tire treads) around the circumference or at an angle to the circumference, or combinations thereof. The dimples may also be of any other suitable configuration. In another alternative embodiment, the single sleeve may comprise a dimpled region extending along part of the single sleeve or the entire sleeve. The sleeve(s) are removed prior to use of the stent delivery system. Brief Description of the Figures Figure 1 is a side view of a balloon catheter with a balloon protector according to the present invention having inner and outer sleeves, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 2 is an even more enlarged view in longitudinal cross-section of the distal portion of the catheter of Figure 1 (indicated by dashed circle 2); Figure 3 a is a perspective view of a balloon protector sleeve according to the present invention; Figure 3b is a side view thereof; Figure 4a is a perspective view of an alternative balloon protector sleeve according to the present invention and Figure 4b is a side partial section view of an alternative balloon protector sleeve according to the present invention; Figure 5 is an even more enlarged cross-section view taken along line 5-5 of Figure 1; Figures 6a-c are side views of alternative balloon protector sleeves according to the present invention; Figure 7 is a side section view of an alternative balloon protector sleeve according to the present invention; Figure 8 is a side view of a further alternative balloon protector sleeve according to the present invention; Figures 9a-h and j are side views of further alternative balloon protector sleeves according to the present invention; Figures lOa-d are perspective views of further alternative balloon protector sleeves according to the present invention; Figure 11 is a side view of a balloon catheter with a balloon protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 12 is a side sectional view taken along line 12-12 of Figure 11; Figure 13 is a side view of an alternative balloon catheter with balloon protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 14 is an even more enlarged view in longitudinal cross-section of the distal portion of the catheter of Figure 13 (indicated by dashed circle 14); Figure 15 is a side view of an alternative balloon catheter with balloon protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 16 is an even more enlarged view in longitudinal cross-section of the distal portion of the catheter of Figure 15 (indicated by dashed circle 16); Figure 17 is a side view of an alternative balloon catheter with balloon protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 18 is an even more enlarged view in longitudinal cross-section of the distal portion of the catheter of Figure 17 (indicated by dashed circle 17); Figure 19 is a side view of a stent delivery system according to the present invention with stent protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 20 is an even more enlarged view in longitudinal cross-section of the distal portion of the stent delivery system of Figure 19 (indicated by dashed circle 20); Figure 21 is a side view of an alternative stent delivery system with stent protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 22 is an even more enlarged view in longitudinal cross-section of the distal portion of the stent delivery system of Figure 21 (indicated by dashed circle 22); Figure 23 is a side view of an alternative balloon catheter with balloon protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 24 is an even more enlarged view in longitudinal cross-section of the distal portion of the stent delivery system of Figure 23 (indicated by dashed circle 24); Figure 25 is an enlarged cross-section view taken along line 25-25 of Figures 19, 21 and 23; Figure 26 is a perspective view of a stent protector sleeve according to the present invention; Figure 27a is a perspective view of an alternative stent protector sleeve according to the present invention, and Figure 27b is a side partial section view of an alternative stent protector sleeve according to the present invention; Figures 28a-c are side views of alternative balloon protector sleeves according to the present invention; Figure 29 is a side section view of an alternative stent protector sleeve according to the present invention; Figure 30 is a side view of a further alternative stent protector sleeve according to the present invention; Figures 31 a-h and j are side views of further alternative stent protector sleeves according to the present invention; Figures 32a-d are perspective views of further alternative stent protector sleeves according to the present invention; Figure 33 is a side view of a stent delivery system with a stent protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 34 is a cross sectional view of the stent delivery system of claim 33 taken along line 34-34; and Figure 35 is a side view of a stent delivery system with a stent protector according to the present invention, wherein the distal portion of the catheter thereof is in longitudinal section view which is enlarged relative to the proximal portion of said catheter; Figure 36 is a cross sectional view of the stent delivery system of claim 35 taken along line 36-36; Figures 37-42 are cross sectional views of a stent delivery system as in Figures 33 and 35, showing alternative configurations of a stent protector means thereof; and Figures 43-45 are schematic representations of means for expanding the expandable member of the balloon catheters and stent delivery systems of the present invention. Figures 46-48 are side partial section views of alternative embodiments of a single sleeve balloon protector having a continuous tubular region and a region having a helical slit therein defining a spiral cut region; Figure 49 is a longitudinal section view of a balloon catheter with a balloon protector according to the present invention; Figure 50 is a perspective view of a single sleeve balloon protector according to the present invention, the balloon protector having a helical slit therein defining a spiral cut region, and a continuous tubular region further comprising a dimpled region and a straight tubular region; Figure 51 is a side cross sectional view of the balloon protector as in Figure 50, taken along the longitudinal axis thereof; Figure 52 is a perspective view of a single sleeve balloon protector according to the present invention, the balloon protector having a helical slit therein defining a spiral cut region, and a continuous tubular region further comprising a dimpled region and a straight tubular region; Figure 53 is a side cross sectional view of the balloon protector as in Figure 52, taken along the longitudinal axis thereof; Figure 54 is a perspective view of a single sleeve balloon protector according to the present invention, the balloon protector having a dimpled region; Figure 55 is a side cross sectional view of the balloon protector as in Figure 54, taken along the longitudinal axis thereof; and Figure 56 is a perspective view of a single sleeve balloon protector according to the present invention, the balloon protector having a dimpled region along the entire length thereof. Description of the Preferred Embodiments Referring to Figures 1-2, a medical device comprising a balloon catheter with a balloon protector according to the present invention is generally indicated at 10. As shown at Figure 1, catheter 12 has a shaft 13, a proximal portion 14 and a distal portion, indicated generally at 16, in longitudinal section view which is enlarged relative to the view of the proximal portion of said catheter. Distal portion 16 is fixed to catheter 12 by standard means known in the art. For instance, distal portion 16 may be bonded at its ends by adhesive to the catheter in an integral manner, or may be made one-piece with the catheter as is known in the art. Distal end portion 16 comprises balloon 22, which is constructed and arranged for expansion from a contracted state to an expanded state. Figure 2 shows distal end portion 16 in an even more enlarged longitudinal cross-sectional view. Balloon 22 may be of any length. For instance, balloon 22 may be about 15 mm long. This length, however, is for illustrative purposes only and is not meant to be limiting. Balloon 22 is shown in its contracted state in Figures 1-2. Balloon 22 may be folded or otherwise collapsed. Balloon 22 or any balloon set forth herein, may be made of a material which resiliently deforms under radial pressure. Examples of suitable materials are generally known in the art and include non-compliant, semi- compliant and compliant materials such as polyethylene (PE), nylon, polyether block amides (PEBAX), polyethylene terephthalate (PET), silicone, POC and the like. In addition, balloon 22 or any balloon set forth herein could be made of arnitel resin, such as Arnitel EM 740 sold by DSM Engineering Plastics, as set forth in U.S. Patent No. 5,556,383, incorporated herein by reference. In use, balloon 22 has a larger diameter which is obtained when the balloon 22 is expanded in the known manner. Catheter balloon 22 may be inflated by fluid (gas or liquid) from an inflation port extending from an inflation lumen contained in the catheter shaft 13 and opening into the balloon 22, or by other means, such as from fluid communication from a passageway or passageways formed between the outside of the catheter shaft and the membrane forming the balloon (schematically shown at Figures 43 -45), depending on the design of the catheter. The passageway(s) could be either lead from the catheter shaft directly to the interior of the balloon (as shown at A in Figure 43) or could lead to the exterior of the balloon (as shown at B of Figure 44). The catheter may be associated with a source of fluid (gas or liquid) external to the catheter (schematically shown at Figure 43), whereby the fluid is delivered to the balloon or expandable member by an inflation lumen located in the catheter shaft 13 and associated with the balloon 22. The details and mechanics of balloon inflation and specific overall catheter construction will vary according to the design of the catheter, and are known in the art per se. All of these variations are acceptable for use with the balloon catheters and stent delivery systems of the present invention. Balloon catheter 10 further comprises balloon protector means, indicated generally at 26, comprising two removable sleeves. Two sleeves as described herein enhance compression of the balloon and provide a better profile. First removable (inner) protector sleeve 28 and second removable (outer) protector sleeve 40 may be made of any suitable low-friction material. Inner and outer sleeves 28,40 may be made of a low friction material which also will not stick to catheter 12 or balloon 22. A non- limiting example of a suitable material in is polytetrafluoroethylene. Inner sleeve 28 may be made of a lubricious plastic material or a material which is lubriciously coated. In an alternative embodiment, outer balloon protector may be made of a shape memory metal or a shape memory polymer. The memory metal and memory polymer materials can be cast or molded and stretched to a larger size inner diameter. An outer balloon protector made of these materials provides the advantage of ease of insertion of the balloon therein since the balloon protector starts out with a larger diameter. Upon thermal or mechanical activation (such as by heating or twisting, for example) of the balloon protector of memory material, the balloon protector shrinks and tightens down, providing a reduced profile. Use of the inventive memory polymer balloon protector may require additional compression of the balloon before the set. A balloon protector made of a shape memory metal or shape memory polymer may be used with or without an inner sleeve. As shown at Figures 1-2, first removable (inner) sleeve 28 is positioned around balloon 22. Inner sleeve 28 has a length less than or equal to the length of balloon 22 in its compressed state. Inner sleeve 28 comprises a straight tube with a first end 32, a second end 34 and a slit 36 therethrough (shown best at Figures 3a-b). Slit 36 extends all the way along inner sleeve 28, from first end 32 to second end 34. Slit 36 is shown in Figures 3a-b as a longitudinal slit 37 extending the length of inner sleeve 28. An alternative embodiment of inner sleeve 28, as shown in Figures 4a and 4b, has a spiral slit 39. Optionally, inner sleeve 28 may have a tail 38 at its second end 34, to assist in its removal. Any outer sleeve, or a singular sleeve according to the present invention may be provided with the same configuration as shown at Figures 3-4 and 6-10. Inner protector sleeve 28 is applied to catheter 12 over balloon 22 by moving inner sleeve 28 in a proximal direction from the distal end 16 of catheter 12, or alternatively by moving inner sleeve 28 in a distal direction from proximal end 14 of catheter 12. Inner sleeve 28 is gently urged over balloon 22 as sleeve is moved in a proximal direction relative to catheter 12. Slit 36 provides inner sleeve 28 with a variable inner diameter, which reduces the force required to apply inner sleeve 28 over balloon 22 by reducing friction between balloon 22 and the interior wall of inner sleeve 28. This ensures that balloon 22 and inner sleeve 28 will not be damaged during application or removal. Referring to Figure 5, an enlarged cross-sectional view, second removable (outer) sleeve 40 is positioned over balloon 22 and inner sleeve 28. Balloon 22 is shown in its contracted state in Figure 5. Outer sleeve 40 as shown in Figures 1-2 is a straight tube. Referring to Figures 6a-c, outer sleeve 40 may be a traditional balloon protector as shown at Figure 6a having a main tubular body portion 42 with a proximal end 44 and a distal end 46 and having a flange 48 at its proximal end 44, a sleeve as shown at Figure 6b with a flange 49 at its distal end 46, or as shown at Figure 6c with flanges 48,49 at both proximal and distal ends 44,46. Sleeve 40 may also be a straight tube 50 with a tapered "lead-in" 52 as shown at Figure 7, or the like. Other configurations will be readily apparent to those familiar with this art. The sleeves shown at Figures 6a-c can also be used as an outer sleeve with any suitable inner sleeve. The sleeve shown at Figure 7 may also be used as a single sleeve balloon protector. Referring to Figure 8, an inner sleeve, outer sleeve or singular sleeve balloon protector of the present invention may also be provided in the form of a polymeric tube 60 with flared proximal end 62, flared distal end 64 and a longitudinal slit 37. This inventive balloon protector is unique in that the balloon protector can be removed from the catheter after the catheter has been prepped and loaded onto a guide wire. This allows the balloon protector to be peeled off the shaft, like peeling a banana. Such a construction allows a doctor to prep and introduce the guide wire into the catheter without touching the balloon. A balloon protector according to the present invention may be a spiral sleeve 66 made of a polymeric material or a metal ribbon. It can also be formed by spiral cutting a tube to be the balloon protector, in a configuration as shown in Figures 9a-h and j and as shown at Figures 4a-b. This balloon protector conforms to diameter changes throughout the length of the collapsed balloon, and in a preferred embodiment has a pre-mounted inner diameter which is less than the outer diameter of the collapsed balloon to provide radial compression when applied on the balloon. The radial strength of the spiral sleeve is related to the material of which the sleeve is made, the pitch of the spiral, the wall thickness of the sleeve and the inner diameter of the sleeve. A preferred material for this balloon protector is LDPE. The spiral sleeve provides a device with a compressive force that has flexibility to conform to diameter changes of a collapsed balloon (a balloon which when expanded has a non-uniform diameter). The spiral sleeve 66 may be used alone as a single balloon protector, or as an inner sleeve with any suitable outer sleeve, for example, a sleeve with a longitudinal slit as shown at Figures 3 and 8. The spiral sleeve 66 may also be used as an outer sleeve with any suitable inner sleeve, for example, a sleeve with a longitudinal slit as shown at Figures 3 and 8. Figures 9a-h and j show alternative embodiments of a spiral sleeve according to the present invention. Figure 9a and 9b show a spiral sleeve with a flare at one end, Figure 9a showing a spiral sleeve with a proximal flare 48, and figure 9b showing a distal flare 49. Figure 9c shows a spiral sleeve 66 with proximal and distal flares 48,49. Prior to use (in a premounted state) the spiral sleeves shown in Figures 9a- c have a substantially uniform outer diameter, inner diameter and wall thickness. Figure 9d shows a spiral sleeve with proximal and distal flares 48,49. Figure 9e shows a spiral sleeve with a distal flare. Figure 9f shows a spiral sleeve with a proximal flare. Prior to use (in a premounted state) the spiral sleeves shown in Figures 9d -f have a substantially uniform outer diameter, a non-uniform, tapered inner diameter and a non-uniform wall thickness. Figure 9g shows a spiral sleeve with proximal and distal flares 48,49. Figure 9h shows a spiral sleeve with a proximal flare 48. Figure 9j shows a spiral sleeve with a distal flare 49. Prior to use (in a premounted state) Figures 9g, h and j have a non- uniform tapered inner and outer diameter, and a substantially uniform wall thickness. A balloon may have various geometries over its length due to non- uniform areas. The spiral sleeve will conform around all portions and compress them. Following construction of a catheter, the balloon is formed and may be folded in multiple ways. For example, the balloon may be folded in a tri-fold manner. Referring now to Figures lOa-d, a further embodiment of a balloon protector means according to the present invention may be provided in the form of a coiled flat wire 70, spring wound without a gap between the coils, as shown at Figures 10a and 10c. Prior to thermal (such as by heating, for example), the coiled flat wire 70 may have a configuration as shown in Figures 10b and lOd. Upon thermal activation, the coiled flat wire 70 shrinks and tightens down, providing a reduced profile as shown in Figures 10a and 10c. Prior to mechanical activation, the coiled flat wire 70 may have a configuration as shown in Figures 10a and 10c. Upon mechanical activation (such as by twisting, for example), the coiled flat wire 70 is expanded to a configuration as shown in Figures 10b and lOd, allowing it to be applied on the catheter. Releasing the coiled flat wire 70 allows it to shrink and tighten down, providing a reduced profile as shown in Figures 10a and 10c. The coiled flat wire 70 may also be provided in a configuration as shown in Figures 4a-b. The embodiment shown at Figures lOa-d has an optional mechanical activation means 71. Mechanical activation means may be removable following mechanical activation or alternatively may be constructed and arranged for retention with coiled wire sleeve 70 and removal prior to use of catheter 12. The mechanical activation means may be of any suitable configuration, and is not intended to be limited hereby. This outer balloon protector is a "one size fits all" which will accommodate all balloons, with or without stents in a delivery configuration. The advantages provided by this configuration is that it provides a "better squeeze" or higher externally applied compressive force than previous press-fit balloon protectors in the art. This configuration provides a compressive force that is variable along the length of the device, thereby providing a uniform compression amount along the entire length of a device which may or may not have a variable diameter. This balloon protector is easier to apply to a balloon than previous balloon protectors known in the art. Since the collapse column strength and friction forces are taken out of the assembly process, the production yield associated with catheters employing this balloon protector is improved. Prior to placement of sleeves 28 and 40 on the catheter, outer sleeve 40 has an inner diameter less than the outer diameter of the inner sleeve 28. In a preferred embodiment, the inner diameter of outer protector sleeve 40 slightly smaller (about 0.001 inch smaller, for example) than the outer diameter of inner protector sleeve 28. This causes slit 36 to be closed when outer protector sleeve 40 is applied over inner protector sleeve 28, in addition to overall compression of inner protective sleeve 28. Inner sleeve 28 locates and holds balloon 22 while relatively tight outer sleeve 40 is pulled on. The lubricity of inner sleeve 28 reduces friction and enables outer sleeve 40 to be easily applied and removed from inner sleeve 28. Inner sleeve 28 provides the additional benefit of protecting the balloon 22 from damage. As slit 36 is closed and forced together by outer protective sleeve 40, balloon 22 becomes more tightly wrapped and held. When outer sleeve 40 is in place, inner sleeve 28 is compressed by outer sleeve 40, and compressed inner sleeve 28 has an inner diameter approximately equal to the outer diameter of the compressed balloon. Outer sleeve 40 closes slit 36, and holds inner sleeve 28, and balloon 22 in place during sterilization and heat set profile forming (such as is disclosed in U.S. 5,342,307, incorporated herein by reference). After both sleeves 28,40 are in place at distal end 16 of catheter 12, a heated sterilization cycle may be performed. Balloon 22 will thereby by heat set into a further compressed form. The heat setting of balloon 22 provides a "memory" to balloon 22 so that when inner and outer sleeves 28,40 are removed prior to use, balloon 22 will remain in its compressed form. Even after inflation and deflation balloon 22 will tend to return to substantially the same shape as it had during the heat sterilization process. Therefore, small profiles can be achieved even after balloon inflation. Inner and outer sleeves 28,40 are removed from catheter 12 prior to use thereof. Outer sleeve 40 is removed by pulling it off catheter 12. Inner sleeve 24 is removed in like manner, or pulled off using optional tail 38. During delivery, the balloon catheter is advanced through and positioned in a patient's vasculature so that balloon is adjacent to the portion of the vessel where treatment is to take place. Balloon 22 is inflated and expanded to an enlarged diameter. Following use of balloon 22, balloon 22 is deflated so that catheter 12 may be removed. Referring now to Figures 11 and 12, wherein like features are designated by the same reference numerals, an alternative embodiment of a balloon catheter having a balloon protector according to the present invention is shown, wherein like features are designated by the same reference numerals as in Figure 1. Balloon 22 is a folded balloon and the balloon protector 40 as shown is a single sleeve. Although any suitable sleeve according to the present invention may be used, the sleeve shown corresponds to that shown in Figure 7. Referring now to Figures 13-14, a balloon catheter with a balloon protector according to the present invention is generally indicated at 10. As shown at Figure 14, catheter 12 has a shaft 13, a proximal portion 14 and a distal portion, indicated generally at 16, in longitudinal section view which is enlarged relative to the view of the proximal portion of said catheter. Distal portion 16 is fixed to catheter 12 by standard means known in the art. For instance, distal portion 16 may be bonded at its ends by adhesive to the catheter in an integral manner, or may be made one-piece with the catheter as is known in the art. Distal end portion 16 comprises balloon 22, which is constructed and arranged for expansion from a contracted state to an expanded state. Figure 14 shows distal end portion 16 in an even more enlarged longitudinal cross-sectional view. As shown in Figures 13-14, distal end portion 16 further comprises a distal dam (or stop) 20. Dam 20 may be conical or ringlike in shape, extending around the circumference of catheter 12. The majority of balloon 22 is located proximally of distal dam 20, a portion of balloon 22 covering and extending distally of distal dam 20. As shown at Figures 15-16, which correspond respectively to Figures 13- 14 and wherein like features are designated by the same reference numerals, catheter 12 may also have a single dam located at its proximal portion. In this embodiment, the majority of balloon 22 is located distally of proximal dam 18, a portion of the balloon 22 covering and extending proximally of proximal dam 18. Referring to Figures 17-18, which correspond respectively to Figures 13- 14, and wherein like features are designated by the same reference numerals, an alternative embodiment of balloon catheter 12 is shown wherein distal portion 16 further comprises proximal dam 18 spaced a predetermined distance from distal dam 20. Balloon 22 is located over and between dams 18,20. Balloon 22 is shown in its contracted state in Figures 13-18. Balloon 22 may be folded or otherwise collapsed. Balloon 22 may be of any length. For instance, balloon 22 may be about 15 mm long in its contracted state. This length, however, is for illustrative purposes only and is not meant to be limiting. Balloon 22 may be made of a material which resiliently deforms under radial pressure. Examples of suitable materials are generally known in the art and include non-compliant, semi-compliant and compliant materials such as polyethylene (PE), nylon, polyether block amides (PEBAX), polyethylene terephthalate (PET), silicone, POC and the like. In addition, balloon 22 could be made of arnitel resin, such as Arnitel EM 740 sold by DSM Engineering Plastics, as set forth in U.S. Patent No. 5,556,383, incorporated herein by reference. In use, balloon 22 has a larger diameter which is obtained when the balloon 22 is expanded in the known manner. Catheter balloon 22 may be inflated by fluid (gas or liquid) from an inflation port extending from a lumen contained in the catheter shaft 13 and opening into the balloon, or by other means, such as from fluid communication from a passageway formed between the outside of the catheter shaft and the membrane forming the balloon, depending on the design of the catheter. The catheter may be associated with a source of fluid (gas or liquid) external to the catheter, whereby the fluid is delivered to the balloon or expandable member by an inflation lumen located in the catheter shaft 13 and associated with the balloon 22. The details and mechanics of balloon inflation and specific overall catheter construction will vary according to the design of the catheter, and are known in the art per se. All of these variations are acceptable for use with this invention. Balloon catheter 10 further comprises balloon protector means, indicated generally at 26, comprising two removable sleeves. Two sleeves as described herein enhance compression of the balloon and provide a better profile. In this embodiment, the two sleeves may provide compression of the balloon at or below the dam (or stop) profile. First removable (inner) protector sleeve 28 and second removable (outer) protector sleeve 40 may be made of any suitable low-friction material. Inner and outer sleeves 28,40 may be made of a low friction material which also will not stick to catheter 12 or balloon 22. A non-limiting example of such a material is polytetrafluoroethylene. Inner sleeve 28 may be made of a lubricious plastic material or a material which is lubriciously coated. In an alternative embodiment, outer balloon protector may be made of a shape memory metal or a shape memory polymer. The memory metal and memory polymer materials can be cast or molded and stretched to a larger size inner diameter. An outer balloon protector made of these materials provides the advantage of ease of insertion of the balloon therein since the balloon protector starts out with a larger diameter. Upon thermal or mechanical activation (such as by heating or twisting, for example) of the balloon protector of memory material, the balloon protector shrinks and tightens down, providing a reduced profile. Use of the inventive memory polymer balloon protector may require additional compression of the balloon before the set. A balloon protector made of a shape memory metal or shape memory polymer may be used with or without an inner sleeve. As shown at Figures 17-18, first removable (inner) sleeve 28 is positioned around balloon 22. Inner sleeve 28 has a length less than or equal to that of balloon 22 in its compressed state. Inner sleeve 28 comprises a straight tube with a first end 32, a second end 34 and a slit 36 therethrough. Slit 36 extends all the way along inner sleeve 28, from first end 32 to second end 34. Slit 36 is shown in Figures 3a-b as a longitudinal slit 37 extending the length of inner sleeve 28. An alternative embodiment of inner sleeve 28, as shown in Figures 4a and 4b, has a spiral slit 39. Optionally, inner sleeve 28 may have a tail 38 at its second end 34, to assist in its removal. Any outer sleeve, or a singular sleeve according to the present invention may be provided with the same configuration as shown at Figures 3-4 and 6-10. In the embodiment shown at Figures 13-18, inner protector sleeve 28 is applied to catheter 12 over balloon 22 by moving inner sleeve 28 in a proximal direction from the distal end 16 of catheter 12, or alternatively by moving inner sleeve 28 in a distal direction from the proximal end 14 of catheter 12. Inner sleeve 28 is gently urged over balloon 22 as sleeve is moved in a proximal direction relative to catheter 12. Slit 36 provides inner sleeve 28 with a variable inner diameter, which 5 reduces the force required to apply inner sleeve 28 over balloon 22 by reducing friction between balloon 22 and the interior wall of inner sleeve 28. This ensures that balloon 22 or inner sleeve 28 will not be damaged during application or removal. Referring to Figure 5, an enlarged cross-sectional view, second removable (outer) sleeve 40 is positioned over balloon 22 and inner sleeve 28. Balloon 10 22 is shown in its contracted state in Figure 5. In the embodiment shown at Figures 17- 18, outer sleeve extends over dams 18,20. Outer sleeve 40 as shown in Figures 13-18 is a straight tube. Referring to Figures 6a-c, outer sleeve 40 may be a traditional balloon protector as shown at Figure 6a having a main tubular body portion 42 with a proximal end 44 and a distal end 15 46, and having a flange 48 at its proximal end 44, as shown at Figure 6b having a flange 49 at its distal end 46, or as shown at Figure 6c having flanges 48,49 at proximal and distal ends 44,46. Outer sleeve may be a straight tube 50 with a tapered "lead-in" 52 as shown at Figure 7. Other configurations will be readily apparent to those familiar with this art. The sleeves shown at Figures 6a-c can also be used as an outer sleeve with any 20 suitable inner sleeve. The sleeve shown at Figure 7 may also be used as a single sleeve balloon protector. Referring to Figure 8, an inner sleeve, outer sleeve or singular sleeve balloon protector of the present invention may also be provided in the form of a polymeric tube 60 with flared proximal end 62, flared distal end 64 and a longitudinal 25 slit 37. This inventive balloon protector is unique in that the balloon protector can be removed from the catheter after the catheter has been prepped and loaded onto a guide wire. This allows the balloon protector to be peeled off the shaft, like peeling a banana. Such a construction allows a doctor to prep and introduce the guide wire into the catheter without touching the balloon. 30 A balloon protector according to the present invention may be a spiral sleeve made of a polymeric material or a metal ribbon. It can also be formed by spiral cutting a tube to be the balloon protector, in a configuration as shown in Figures 9a-c or in Figures 4a-b. This balloon protector conforms to diameter changes throughout the length of the collapsed balloon, and in a preferred embodiment has a pre-mounted inner diameter which is less than the outer diameter of the collapsed balloon to provide radial compression when applied on the balloon. The radial strength of the spiral sleeve is related to the material of which the sleeve is made, the pitch of the spiral, the wall thickness of the sleeve and the inner diameter of the sleeve. A preferred material for this balloon protector is LDPE. The spiral sleeve provides a device with a compressive force that has flexibility to conform to diameter changes of a collapsed balloon (a balloon which when expanded has a non-uniform diameter). The spiral sleeve 66 may be used alone as a single balloon protector, or as an inner sleeve with any suitable outer sleeve, for example, a sleeve with a longitudinal slit as shown at Figures 3 and 8. The spiral sleeve 66 may also be used as an outer sleeve with any suitable inner sleeve, for example, a sleeve with a longitudinal slit as shown at Figures 3 and 8. A balloon may have various geometries over its length due to non- uniform areas. The spiral sleeve will conform around all portions and compress them. Following construction of a catheter, the balloon is formed and may be folded in multiple ways. For example, the balloon may be folded in a tri-fold manner. Referring to Figures lOa-d, a further embodiment of an outer balloon protector according to the present invention may be provided in the form of a coiled flat wire 70, spring wound without a gap between the coils, as shown at Figures 10a and 10c. Prior to thermal or mechanical activation (such as by heating or twisting, for example, the coiled flat wire 70 may have a configuration as shown in Figures 10b and lOd. Upon thermal or mechanical activation, the coiled flat wire 70 shrinks and tightens down, providing a reduced profile as shown in Figures 10a and 10c. The embodiment shown at Figures lOa-d has an optional mechanical activation means 71. Mechanical activation means may be removable following mechanical activation or alternatively may be constructed and arranged for retention with coiled wire sleeve 70 and removal prior to use of catheter 12. The mechanical activation means may be of any suitable configuration, and is not intended to be limited hereby. This outer balloon protector is a "one size fits all" which will accommodate all balloons, with or without stents in a delivery configuration. The advantage provided by this configuration is that it provides a "better squeeze" or higher externally applied compressive force than previous press-fit balloon protectors in the art. This configuration provides a compressive force that is variable along the length of the device, thereby providing a uniform compression amount along the entire length of a device which may or may not have a variable diameter. This balloon protector is easier to apply to a balloon than previous balloon protectors known in the art. Since the collapse column strength and friction forces are taken out of the assembly process, the production yield associated with catheters employing this balloon protector is improved. Prior to mounting inner sleeve 28 and outer sleeve 40 on a catheter, outer sleeve 40 has an inner diameter less than the outer diameter of the inner sleeve 28. In a preferred embodiment, the inner diameter of outer protector sleeve 40 is slightly smaller (for example, about 0.001 inch smaller) than the outer diameter of inner protector sleeve 28. This causes slit 36 to be closed when outer protector sleeve 40 is applied over inner protector sleeve 28, in addition to overall compression of inner protective sleeve 28. Inner sleeve 28 locates and holds balloon 22 while relatively tight outer sleeve 40 is pulled on. The lubricity of inner sleeve 28 reduces friction and enables outer sleeve 40 to be easily applied and removed from inner sleeve 28. Inner sleeve 28 provides the additional benefit of protecting the balloon 22 from damage. As slit 36 is closed and forced together by outer protective sleeve 40, balloon 22 becomes more tightly wrapped and held. When outer sleeve 40 is in place, inner sleeve 28 is compressed by outer sleeve 40, and compressed inner sleeve 28 has an inner diameter approximately equal to the combined diameter of the compressed balloon and the dam. Outer sleeve 40 closes slit 36, and holds inner sleeve 28, and balloon 22 in place during sterilization and heat set profile forming (such as is disclosed in U.S. 5,342,307). After both sleeves 28,40 are in place at distal end 16 of catheter 12, a heated sterilization cycle may be performed. Balloon 22 will thereby by heat set into a further compressed form. The heat setting of balloon 22 provides a "memory" to balloon 22 so that when inner and outer sleeves 28,40 are removed prior to use, balloon 22 will remain in its compressed form. Even after inflation and deflation balloon 22 will tend to return to substantially the same shape as it had during the heat sterilization process. Therefore, small profiles can be achieved even after balloon inflation. Inner and outer sleeves 28,40 are removed from catheter 12 prior to use thereof. Outer sleeve 40 is removed by pulling it off catheter 12. Inner sleeve 24 is removed in like manner, or pulled off using optional tail 38. During delivery, the balloon catheter is advanced through and positioned in a patient's vasculature so that balloon is adjacent to the portion of the vessel where treatment is to take place. Balloon 22 is inflated and expanded to an enlarged diameter. Following use of balloon 22, balloon 22 is deflated so that catheter 12 may be removed. Referring to Figures 19-20, a stent delivery system according to the present invention is indicated generally at 110. As shown at Figure 20, stent delivery system 110 includes a catheter 112 having a shaft 113, a proximal portion 114 and a distal portion (indicated generally at 116) in longitudinal section view which is enlarged relative to the view of the proximal portion of said catheter. Distal portion 116 is fixed to catheter 112 by standard means known in the art. For instance, distal portion 116 may be bonded at its ends by adhesive to the catheter in an integral manner, or may be made one-piece with the catheter as is known in the art. Distal portion 116 is constructed and arranged for expansion of its outer diameter from a contracted state to an expanded state. Figure 20 shows distal end portion in an even more enlarged longitudinal cross- sectional view. As shown in Figure 20, distal end portion 116 further comprises a distal dam (or stop) 120. Dam 120 may be conical or ring-like in shape, extending around the circumference of catheter 112. Balloon 122 is located proximally of distal dam 120. As shown at Figures 21-22, which correspond respectively to Figures 19- 20 and wherein like features are designated by the same reference numerals, catheter 112 may also have a single dam located at its proximal portion. In this embodiment, balloon 122 is located distally of proximal dam 118. Referring to Figures 23-24, which correspond respectively to Figures 19- 20, and wherein like features are designated by the same reference numerals, an alternative embodiment of balloon catheter 112 is shown wherein distal portion 116 comprises two dams, proximal dam 118 being spaced a predetermined distance from distal dam 120. Balloon 122 is located over and between dams 118,120. Balloon is shown in its contracted state in Figures 19-24. Balloon 122 may be folded or otherwise collapsed. Balloon 122 may be made of a material which resiliently deforms under radial pressure. Examples of suitable materials are generally known in the art and include non-compliant, semi-compliant and compliant materials such as polyethylene (PE), nylon, polyether block amides (PEB AX), polyethylene terephthalate (PET), silicone, POC and the like. In addition, balloon 122 could be made of arnitel resin, such as Arnitel EM 740 sold by DSM Engineering Plastics, as set forth in U.S. Patent No. 5,556,383, incorporated herein by reference. Referring to Figure 25, an enlarged cross-sectional view of a cross section taken along line 25-25 of Figures 19, 21 and 23, second removable (outer) sleeve 140 is positioned over balloon 122, stent 124 and inner sleeve 128. Balloon 122 is shown in its contracted state in Figure 25. As shown in Figures 19-20, outer sleeve 140 extends over distal dam 120. As shown in Figures 21-22, outer sleeve 140 extends over proximal dam 118. In the embodiment shown at Figures 23-24, outer sleeve extends over dams 118,120. Referring to Figures 19-24, catheter 112 has a shaft 113, a proximal portion 114 and a distal portion, indicated generally at 116, in longitudinal section view which is enlarged relative to the view of the proximal portion of said catheter. Distal portion 116 is fixed to catheter 112 by standard means known in the art. For instance, distal portion 116 may be bonded at its ends by adhesive to the catheter in an integral manner, or may be made one-piece with the catheter as is known in the art. Distal end portion 116 is constructed and arranged for expanding the outer diameter of the catheter from a contracted state to an expanded state. As shown in Figures 19-24, stent 124 is positioned around the distal portion of catheter 112 (around balloon 122). As shown in Figures 19-20, stent 124 is located proximally of single distal dam 120. As shown in Figures 21-22, stent 124 is shown in a location distal to single proximal dam 118. As shown in Figures 23-24, stent 124 is positioned around the distal portion of catheter 112 (around balloon 122) between proximal dam 118 and distal dam 120. Any self-expanding stent or balloon expandable stent may be used with this invention. Many are known in the art including plastic and metal stents. Some are more well known such as the stainless steel stent shown in U.S. Patent 4,735,665; the wire stent shown in U.S. Patent 4,950,227; another metal stent shown in European Patent Application EPO 707 837 Al and that shown in U.S. Patent 5,445,646. All of these patents are incorporated herein by reference. Also, shape memory metal stents may be used. Stent 124 is typically about 15mm long, while balloon 122 is roughly the same length. These dimensions, however, are merely representative for illustrative purposes only and are not meant to be limiting. In the embodiment shown at Figures 23-24 having spaced dams 118,120, the upper limit of the length of stent 124 is defined by the distance between dams 118,120. Stent 124 has a contracted condition and an expanded condition, being sized in its contracted condition to closely surround the catheter. Stent 124 is fixed about balloon 122 by any suitable means as known in the art. For example, stent 124 may be gently crimped onto balloon 122 either by hand or with a tool such as a pliers or the like to be mounted for delivery. Stent 124 has a larger expanded diameter which is obtained when the balloon 122 is expanded in the known manner. That is, stent 124 will be released from catheter 112 upon expansion of balloon 122 to be placed in a vessel. When balloon 122 is then deflated, removal of catheter 112 may be accomplished while leaving stent 124 in place. Catheter balloon 122 may be inflated by fluid (gas or liquid) from an inflation port extending from a lumen contained in the catheter shaft 113 and opening into the balloon 122, or by other means, such as from fluid communication from a passageway formed between the outside of the catheter shaft 113 and the membrane forming the balloon, depending on the design of the catheter. The catheter may be associated with a source of fluid (gas or liquid) external to the catheter, whereby the fluid is delivered to the balloon or expandable member by an inflation lumen located in the catheter shaft 113 and associated with the balloon 122. The details and mechanics of balloon inflation and specific overall catheter construction will vary according to the design of the catheter, and are known in the art per se. All of these variations are acceptable for use with this invention. Stent delivery system 110 further comprises stent protector means, indicated generally at 126, comprising two removable sleeves. Two sleeves as described herein provide a better profile and enable compression of stent 124 below the dam (or stop) profile. First removable (inner) protector sleeve 128 and second removable (outer) protector sleeve 140 may be made of any suitable low-friction material. Inner and outer sleeves 128,140 may be made of a low friction material which also will not stick to catheter 112, balloon 122 or stent 124. An example of a such a material is polytetrafluoroethylene. Inner sleeve 128 may be made of a lubricious plastic material or a material which is lubriciously coated. In alternative embodiment, the outer balloon protector according to the present invention may be made of a shape memory metal or a shape memory polymer. Such memory metal and memory polymer materials can be cast or molded and stretched to a larger size inner diameter. Such a stent protector provides the advantage of ease insertion of the catheter and stent since the stent protector starts out with a larger diameter. Upon thermal or mechanical activation (such as by heating or twisting, for example) of the stent protector of memory material, the stent protector shrinks and tightens down, providing a reduced profile. Use of the inventive memory polymer stent protector will require additional compression of the balloon and stent before the set. Such a stent protector may be used with or without an inner sleeve. As shown at Figures 19-24, first removable (inner) sleeve 128 is positioned around stent 124. Inner sleeve 128 has a length approximately equal to that of stent 124 in its compressed state on catheter 112. Inner sleeve 128 comprises a straight tube with a first end 132, and a second end 134 and a slit 136 therethrough (as shown at Figure 26). Slit 136 extends all the way along inner sleeve 128, from first end 132 to second end 134. Slit 136 is shown in Figure 26 as a longitudinal slit 137 extending the length of inner sleeve 128. An alternative embodiment of inner sleeve 128, as shown in Figures 27a and 27b, has a spiral slit 139. Optionally, inner sleeve 128 may have a tail 138 at its second end 134, to assist in its removal. Any outer sleeve, or a singular sleeve according to the present invention may be provided with the same configuration as shown at Figures 26-27 and 28-32. In the embodiment shown at Figures 19-24, inner protector sleeve 128 may be applied to catheter 112 over balloon 122 and stent 124 by moving inner sleeve 128 in a proximal direction from the distal end 116 of catheter 112. Inner sleeve 128 is then gently urged over stent 124 as sleeve is moved in a proximal direction relative to catheter 112. Alternatively, inner protector sleeve 128 may be applied to catheter 112 over balloon 122 and stent 124 by moving inner sleeve 128 in a distal direction from the proximal end 114 of catheter 112, and inner sleeve 128 is then gently urged over stent 124 as sleeve is moved in a distal direction relative to catheter 112. Slit 136 provides inner sleeve 128 with a variable inner diameter, which reduces the force required to apply inner sleeve 128 over stent 124 by reducing friction between stent 124 and the interior wall of inner sleeve 128, and allows inner sleeve 128 to fit over the dam(s). This ensures that balloon 122 or inner sleeve 128 will not be damaged by stent 124 during application or removal. Outer sleeve 140 as shown in Figures 19-24 is a straight tube. Referring to Figures 28a-c, outer sleeve 140 may be a traditional balloon protector as shown at Figure 28a having a main tubular body portion 142 with a proximal end 144 and a distal end 146 and having a flange 148 at its proximal end 144, as shown at Figure 28b with a flange 149 at its distal end 146, or as shown at Figure 28c with flanges 148,149 at both ends 144,146. Referring to Figure 29, outer sleeve 140 may be a straight tube 150 with a tapered "lead-in" 152. Other configurations will be readily apparent to those familiar with this art. The sleeves shown at Figures 28a-c can also be used as an outer sleeve with any suitable inner sleeve. The sleeve shown at Figure 29 may be used as a single sleeve balloon protector. Referring to Figure 30, an inner sleeve, outer sleeve or singular sleeve stent protector of the present invention may also be provided in the form of a polymeric tube 160 having flared proximal end 162, flared distal end 164 and longitudinal slit 137. This inventive stent protector is unique in that the stent protector can be removed from the catheter after the catheter has been prepped and loaded onto a guide wire. This allows the stent protector to be peeled off the shaft, like peeling a banana. Such a construction allows a doctor to prep and introduce the guide wire into the catheter without touching the preloaded stent. Referring now to Figures 31a-h and j, a further alternative embodiment of a stent protector according to the present invention is a spiral sleeve 166 made of a polymeric material or a metal ribbon. The spiral sleeve can also be formed by spiral cutting a tube to be the stent protector, in a configuration as shown in Figures 31a-c and 27a-b. This stent protector conforms to diameter changes throughout the length of the stent and compressed balloon, and in a preferred embodiment has a pre-mounted inner diameter which is less than the outer diameter of the collapsed balloon to provide radial compression when applied on the balloon. The radial strength of the spiral sleeve is related to the material of which the sleeve is made, the pitch of the spiral, the wall thickness of the sleeve and the inner diameter of the sleeve. A preferred material for this balloon protector is LDPE. The spiral sleeve provides a device with a compressive force that has flexibility to conform to diameter changes of a collapsed balloon (a balloon which when expanded may have a non-uniform diameter) on which a stent is loaded. The spiral sleeve 166 may be used alone as a single stent protector, or as an inner sleeve with any suitable outer sleeve, for example, a sleeve with a longitudinal slit as shown at Figure 26. The spiral sleeve 166 may also be used as an outer sleeve with any suitable inner sleeve, for example, a sleeve with a longitudinal slit as shown at Figure 26. Figures 31a-h and j show alternative embodiments of a spiral sleeve 166 according to the present invention. Figure 31a and 31b show a spiral sleeve with a flare at one end, Figure 31a showing a spiral sleeve with a proximal flare 148, and Figure 31b showing a distal flare 149. Figure 31c shows a spiral sleeve 166 with proximal and distal flares 148,149. Prior to use (in a premounted state) the spiral sleeves shown in Figures 3 la-c have a substantially uniform outer diameter, inner diameter and wall thickness. Figure 3 Id shows a spiral sleeve with proximal and distal flares 148,149. Figure 3 le shows a spiral sleeve with a distal flare 149. Figure 3 If shows a spiral sleeve with a proximal flare 148. Prior to use (in a premounted state) the spiral sleeves shown in Figures 3 Id -f have a substantially uniform outer diameter, a non-uniform, tapered inner diameter and a non-uniform wall thickness. Figure 3 lg shows a spiral sleeve with proximal and distal flares 148,149. Figure 31h shows a spiral sleeve with a proximal flare 148. Figure 31 j shows a spiral sleeve with a distal flare 149. Prior to use (in a premounted state) Figures 31g, h and j have a non-uniform tapered inner and outer diameter, and a substantially uniform wall thickness. This embodiment may be used not only with PTCA balloon catheters, but also with stent delivery systems comprising catheters on which a stent is loaded. The balloon may be folded in multiple ways. For example, the balloon may be folded in a tri-fold manner. A balloon may have various geometries over its length due to non- uniform areas. The stent may be crimped to the balloon. The spiral sleeve will conform around all portions and compress them. Referring now to Figures 32a-d, a further embodiment of an outer stent protector according to the present invention may be provided in the form of a coiled flat wire 170, spring wound without a gap between the coils, as shown at Figures 32a and 32c. Prior to thermal (such as by heating, for example), the coiled flat wire 170 may have a configuration as shown in Figures 32b and 32d. Upon thermal activation, the coiled flat wire 170 shrinks and tightens down, providing a reduced profile as shown in Figures 32a and 32c. Prior to mechanical activation, the coiled flat wire 170 may have a configuration as shown in Figures 32a and 32c. Upon mechanical activation (such as by twisting, for example), the coiled flat wire 170 is expanded to a configuration as shown in Figures 32b and 32d, allowing it to be applied on the catheter. Releasing the coiled flat wire 170 allows it to shrink and tighten down, providing a reduced profile as shown in Figures 32a and 32c. The coiled flat wire 170 may be provided in a configuration as shown at Figures 27a-b. The embodiment shown at Figures 32a-d has an optional mechanical activation means 171. Mechanical activation means may be removable following mechanical activation or alternatively may be constructed and arranged for retention with coiled wire sleeve 170 and removal prior to use of catheter 112. The mechanical activation means may be of any suitable configuration, and is not intended to be limited hereby. This outer stent protector is a "one size fits all" which will accommodate all balloons, with or without stents in a delivery configuration. The advantages provided by this configuration is that it provides a "better squeeze" or higher externally applied compressive force than prior art stent protectors. This configuration provides a compressive force that is variable along the length of the device, thereby providing a uniform compression amount along the entire length of a device which may or may not have a variable diameter. This stent protector is easier to apply over a stent than previous stent protectors known in the art. Since the collapse column strength and friction forces are taken out of the assembly process, the production yield associated with stent delivery devices employing this stent protector is improved. Prior to placement of inner sleeve and outer sleeve 140 on a catheter, outer sleeve 140 has an inner diameter less than the outer diameter of the inner sleeve 128. In a preferred embodiment, the inner diameter of outer protector sleeve 140 is slightly smaller (for example, about 0.001 inch smaller) than the outer diameter of inner protector sleeve 128. This causes slit 136 to be closed when outer protector sleeve 140 is applied over inner protector sleeve 128, in addition to overall compression of inner protective sleeve 128. Inner sleeve 128 locates and holds stent 124 while relatively tight outer sleeve 140 is pulled on. The lubricity of inner sleeve 128 reduces friction and enables outer sleeve 140 to be easily applied and removed from inner sleeve 128. Inner sleeve 128 provides the additional benefit of protecting the stent 124 from damage. As slit 136 is closed and forced together by outer protective sleeve 140, stent 124 becomes more tightly wrapped and held. When outer sleeve 140 is in place, inner sleeve 128 is compressed by outer sleeve 140, and compressed inner sleeve 128 has an inner diameter approximately equal to the sum of the diameter of the compressed balloon and the dam(s). The stent delivery system of the present invention thereby enables compression of the stent below the dam profile. Outer sleeve 140 closes slit 136, and holds inner sleeve 128, stent 124 and balloon 122 in place during sterilization and/or heat set profile forming (such as is disclosed in U.S. 5,342,307). After both sleeves 128,140 are in place at distal end 116 of catheter 112, a heated sterilization cycle may be performed. Balloon 122 will thereby be heat set into a further compressed form. The heat setting of balloon 122 provides a "memory" to balloon 122 so that when inner and outer sleeves 128,140 are removed prior to use, balloon 122 will remain in its compressed form. Even after inflation and deflation balloon 122 will tend to return to substantially the same shape as it had during the heat sterilization process. Therefore, small profiles can be achieved even after balloon inflation. Inner and outer sleeves 128,140 are removed from stent delivery system 110 prior to use of the stent delivery system and deployment of stent 124 by expansion of the balloon. Outer sleeve 140 is removed by pulling it off catheter 112. Inner sleeve 124 is removed in like manner, or pulled off using optional tail 138. During delivery, the balloon catheter is advanced through and positioned in a patient's vasculature so that stent 124 is adjacent to the portion of the vessel where treatment is to take place. Balloon 122 is inflated to expand stent 124 to an enlarged diameter. When stent 124 has reached the desired diameter, balloon 122 is deflated so that catheter 112 may be removed leaving stent 124 in place. Referring now to Figures 33 and 35, alternative embodiments of a stent delivery system according to the present invention are shown generally at 210. Catheter 212 has a shaft 213, a proximal portion 214 and a distal portion, indicated generally at 216, shown in longitudinal section view which is enlarged relative to the view of the proximal portion of said catheter. Distal portion 216 is fixed to catheter 212 by standard means known in the art. For instance, distal portion 216 may be bonded at its ends by adhesive to the catheter in an integral manner, or may be made one-piece with the catheter as is known in the art. Distal portion 216 is constructed and arranged for expanding the outer diameter of the catheter from a contracted state to an expanded state. Distal portion 216 comprises a balloon 222, which has a proximal end 225, and a distal end 226. In the embodiments shown, proximal end 225 of balloon 222 is inwardly tapered and distal end 226 has an enlarged portion 227 which extends over distal dam 220. In Figures 34 and 36, cross sections respectively taken along line 34-34 of Figure 33, and line 35-35 of Figure 35, balloon 222 is shown to be a folded balloon in its compressed state. As shown in Figures 33-34, stent 224 is positioned around the distal portion of catheter 212 (around balloon 222) between proximal end 225 and distal enlarged portion 227 thereof. This embodiment may be used with any stent protector means described herein. Inner sleeve 228 is shown, having approximately the same length as stent 224. Outer sleeve 240 is shown having a length greater than or equal to that of balloon 224. As shown in Figures 35-36, stent 224 is positioned around balloon 222 between proximal end 225 and distal enlarged portion thereof. This embodiment may be used with any single sleeve stent protector according to the present invention. In a most preferred embodiment of the present invention as shown in Figures 35 and 36, the stent protector corresponds to that shown in Figures 27a-b or 3 la-h and j. Referring now to Figures 37-42, cross sectional views showing alternative configurations of a stent protector means indicated generally in Figures 33- 40 at 226. In the embodiment shown in Figure 37, a stent protector means is shown comprising a spiral sleeve 266, as shown in Figures 27 a-b and 3 la-h and j. In the embodiment shown in Figure 38 a stent protector means is shown which comprises an inner sleeve 228 which is a spiral sleeve 266 as shown at Figures 27a-b and 3 la-h and j, and an outer sleeve 240 of the type shown at Figures 28a-c and 29. The embodiment shown at Figure 39 shows a stent protector means comprising an inner sleeve of the type having a longitudinal slit 237, as shown at Figures 26 and 30 and an outer sleeve which is a spiral sleeve 266 as shown at Figures 27a-b and 3 la-h and j. The embodiment shown at Figure 40 is a single sleeve stent protector of the type shown at Figures 26 and 39, which has a longitudinal slit 237. Figure 41 shows an embodiment of a stent protector having an inner sleeve of the type shown at Figures 26 and 30, having a longitudinal slit 237 and an outer sleeve of the type shown at Figures 28a-c and 29. Figure 42 shows a stent protector having an inner sleeve which is a spiral sleeve 266 as shown in Figures 27a-b and 3 la-h and j, and an outer sleeve having a longitudinal slit 237 as shown in Figures 26 and 30. Figures 46-48 are side partial section views of alternative embodiments of a single sleeve balloon or stent protector, indicated generally at 326, having a proximal end 328, a distal end 330, a continuous tubular region 332 and a spiral cut region 334 having a helical slit 336 therein. The embodiments shown at Figure 46-48 are all single sleeve balloon protectors, each having a flare 338 at its proximal end 328, a helical slit 336 defining proximal spiral cut region 334, and a continuous tubular distal region 332. As shown at Figures 46-47, the tubular distal region 332 will extend proximally from the distal end 330 of the balloon protector 326 to the position of the balloon protector which covers the distal end of the most distal marker band, said distal marker band being located interior of balloon 322 and exterior of inner lumen 315 of catheter 312. The embodiment shown at Figure 46 has a relatively shorter distal tubular region than that of the embodiment shown at Figure 47. The length of the continuous tubular region will depend on the placement of the most distal marker band 317. As shown in Figure 48, the proximal end of the distal tubular region may be located at any position from X to Y. Referring now to Figures 49-55, an alternative embodiment of a balloon catheter having a balloon protector according to the present invention is shown. Figure 49 is a longitudinal section view of the distal portion of a balloon catheter with a balloon protector according to the present invention, wherein the distal portion of the catheter thereof is in schematic longitudinal section view with a space between the balloon and balloon protector to show detail. The balloon protector actually closely surrounds the balloon. Balloon 422 is a folded or wrapped balloon and the balloon protector 440 as shown is a single sleeve. Although any suitable sleeve according to the present invention may be used, the sleeve shown corresponds to those shown in Figures 50-53. As shown at Figure 49, catheter 412 has a shaft 413, a proximal portion (not shown) and a distal portion, indicated generally at 416. Distal portion 416 is fixed to catheter 412 by standard means known in the art. For instance, distal portion 416 may be bonded at its ends by adhesive to the catheter in an integral manner, or may be made one-piece with the catheter as is known in the art. Distal end portion 416 comprises balloon 422, having a proximal end 423 and a distal end 425, balloon 422 being shown in a wrapped configuration around inner 427. At its proximal end 423, balloon 422 closely surrounds distal outer 429 at its distal end 431. Balloon 422 is constructed and arranged for expansion from a contracted state to an expanded state. Single sleeve balloon protector 426 has a proximal end 428, a distal end 430, and a dimpled region 440. This balloon protector may be of uniform diameter throughout its length, or tapered such that its diameter at distal end 430 is less than its diameter at proximal end 428. Balloon protector 426 will closely surround balloon 422. Figures 50-53 are views of alternative embodiments of a single sleeve balloon or stent protector, indicated generally at 426, having a proximal end 428, a distal end 430, a continuous tubular region 432 and a spiral cut region 434 having a helical slit 436 therein. Each of the single sleeve balloon protectors shown at Figures 50-53 has a flare 438 at its proximal end 428, a helical slit 436 defining proximal spiral cut region 434, and a continuous tubular distal region 432. The inventive balloon protector as shown may optionally be provided without a proximal flare. Figure 50 is a perspective view of a single sleeve balloon protector according to the present invention, the balloon protector having a helical slit therein defining a spiral cut region, and a continuous tubular region further comprising a dimpled region 440 and a straight, smooth tubular region 442. Figure 51 is a side cross sectional view of the balloon protector of Figure 50. Figure 52 is a perspective view of a single sleeve balloon protector according to the present invention, the balloon protector having a helical slit therein defining a spiral cut region, and a continuous tubular region further comprising a dimpled region 440 that is a spiral dimpled region, and a smooth, straight tubular region 442. Figure 53 is a side cross sectional view of the balloon protector of Figure 52. Alternatively, the balloon protector of the present invention may comprise a continuous tube having a spiral dimpled region 440 extending along part of its length, and a straight, smooth tubular region 442 extending along the remaining length as shown in Figures 54-55, or a spiral dimpled region 440 extending along its entire length, as shown in Figure 56. The balloon protectors shown in Figures 54-56 may optionally be provided with a proximal flare as shown. The balloon protector may be dimpled using a heat source. The dimples may be round-like, round or golf-ball like, spiral, triangular, oblong, longitudinal, circular (like tire treads) around the circumference or at an angle to the circumference, or combinations thereof. The dimples may also be of any other suitable configuration. Portions of the balloon protector may be "dimpled", as shown in Figures 50-55, or the entire balloon protector may be dimpled as shown in Figure 56. The dimples may be provided on a partial length of the balloon protector, one quarter to one half the length, for example, or along the full length of the balloon protector. The dimples are generally not placed in areas corresponding to where marker bands are located. The dimpling disclosed herein is an advantageous feature as it works the fold of the balloon and operates to break down fold edges, allowing smaller balloon protectors to fit over balloons. This yields reduced profiles and enables the catheter to track better and to better cross lesions. Where a balloon protector is altered by the forming of multiple dimples in the material thereof, the dimples deform the inner diameter as well as the outer diameter and exterior surface. This is apparent in the cross sectional views. Dimples as disclosed herein may be formed on straight or tapered balloon protectors or in conjunction with a curved or bent product mandrel and any wrap style including "S", "trifold", or any fold such as quad, fix or six fold, for example. The dimpled feature of the balloon protector, whether the dimples are spiral dimples or round, golf-ball-like dimples, will not only work the balloon cone down when sliding it over the balloon but will also work the balloon while it is removed, thereby enhancing profile reduction. The balloon protector may be twisted on or pushed on. Application by twisting on may lessen proximal bunching of the balloon. This single sleeve balloon protector is a "one size fits all" which will accommodate all balloons, with or without stents in a delivery configuration. The advantage provided by this configuration is that it provides a "better squeeze" or higher externally applied compressive force than previous press-fit balloon protectors in the art. This configuration provides a compressive force that is variable along the length of the device, thereby providing a uniform compression amount along the entire length of a device which may or may not have a variable diameter. This balloon protector is easier to apply to a balloon than previous balloon protectors known in the art. Since the collapse column strength and friction forces are taken out of the assembly process, the production yield associated with catheters employing this balloon protector is improved. Non limiting examples of suitable materials of which the single sleeve balloon or stent protectors of the present invention can be made are PTFE or LDPE. Other suitable materials are generally known in the art and include non-compliant, semi- compliant and compliant materials such as polyethylene (PE), nylon, polyether block amides (PEBAX), polyethylene terephthalate (PET), silicone, POC and the like. In addition, the balloon and stent protectors of the present invention could be made of arnitel resin, such as Arnitel EM 740 sold by DSM Engineering Plastics, as set forth in U.S. Patent No. 5,556,383, incorporated herein by reference. In addition any sleeve set forth herein which may be made of a polymeric material may be made of one of these materials. The above Examples and disclosure are intended to be illustrative and not exhaustive. These examples and description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the attached claims. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims attached hereto.

Claims: WHAT IS CLAIMED IS AS FOLLOWS: I . A medical device comprising: a catheter comprising a proximal portion, a distal portion, a shaft and an expandable member located at the distal portion, said expandable member being constructed and arranged for expanding the outer diameter of said catheter from a contracted state to an expanded state; and protector means comprising a removable sleeve positioned around the expandable member, said sleeve comprising a first end and a second end and having a variable inner diameter. 2. The medical device of claim 1 wherein the expandable member comprises a balloon and the distal portion further comprises at least one dam. 3. The medical device of claim 1 wherein the sleeve comprises a straight tube. 4. The medical device of claim 3 wherein at least a portion of the sleeve is dimpled. 5. The medical device of claim 3 wherein the entire sleeve is dimpled. 6. The medical device of claim 4 wherein the dimples are round-like. 7. The medical device of claim 4 wherein the dimples are helical grooves. 8. The medical device of claim 1 wherein the first end of the sleeve further comprises a proximal flare. 9. The medical device of claim 1 wherein said sleeve has a slit extending therethrough. 10. The medical device of claim 9 wherein the slit is a longitudinal slit extending from the first end of the sleeve to the second end of the sleeve. I I . The medical device of claim 9 wherein the slit is a spiral slit extending in a helical manner from the first end of the sleeve to the second end of the sleeve. 12. The medical device of claim 9 wherein the slit extends distally in a helical manner from the first end of the sleeve and defines a proximal spiral region, said sleeve further comprising a distal continuous tubular portion. 13. The medical device of claim 12 wherein the distal continuous tubular portion further comprises a dimpled region and a substantially smooth region. 14. The medical device of claim 13 wherein the dimples are round-like. 15. The medical device of claim 13 wherein the dimples are helical grooves. 16. The medical device of claim 12 wherein the first end of the sleeve further comprises a proximal flare. 17. A medical device comprising: a catheter comprising a proximal portion, a distal portion, a shaft and an expandable member located at the distal portion, said expandable member being constructed and arranged for expanding the outer diameter of said catheter from a contracted state to an expanded state; and removable protector means comprising: a first removable inner sleeve positioned around the expandable member, said sleeve comprising a first end and a second end and having a variable inner diameter; a second removable outer sleeve positioned over the first sleeve, said second sleeve having a first end and a second end, said first and second sleeves being removed prior to use of the medical device. 18. The medical device of claim 17 wherein the expandable member and the first sleeve are of a material which resiliently deforms under radial pressure. 19. The medical device of claim 17 wherein the first sleeve and the second sleeve are made of a low friction material. 20. The medical device of claim 17 wherein said first sleeve is coextruded and has a high friction inner diameter and a low friction outer diameter, whereby the inner sleeve will not slip when the outer sleeve is pushed thereon. 21. The medical device of claim 17 wherein at least one of said first and second sleeves is a straight or continuous tube. 22. The stent delivery system of claim 21 wherein at least a portion of said at least one continuous tube is dimpled. 23. The medical device of claim 22 wherein the continuous tube has round-like dimples. 24. The medical device of claim 22 wherein the continuous tube has helical grooved dimples. 25. The stent delivery system of claim 22 wherein the entire continuous tube is dimpled. 26. The medical device of claim 17 wherein at least one of said first and second sleeves has a slit extending therethrough. 27. The medical device of claim 26 wherein the slit is a longitudinal slit extending from the first end of the sleeve to the second end of the sleeve. 28. The medical device of claim 26 wherein the slit is a spiral slit extending in a helical manner from the first end of the sleeve to the second end of the sleeve. 29. The medical device of claim 26 wherein the slit extends distally in a helical manner from the first end of the sleeve and defines a proximal spiral region, said sleeve further comprising a distal continuous tubular portion. 30. The medical device of claim 29 wherein the distal continuous tubular portion further comprises a dimpled region and a substantially smooth region. 31. The medical device of claim 30 wherein the dimples are round-like. 32. The medical device of claim 30 wherein the dimples are helical grooves. 33. The medical device of claim 17 wherein the distal portion of the catheter further comprises at least one enlarged portion, whereby when compressed by the outer sleeve, the inner sleeve will have an inner diameter less than or equal to the outer diameter of the at least one enlarged portion. 34. The medical device of claim 33 wherein the at least one enlarged portion comprises a proximal dam and a distal dam spaced a predetermined distance apart, said dams having an equal outer diameter, and the expandable member comprises a balloon located over and between said dams. 35. A stent delivery system comprising: a catheter comprising a proximal portion, a distal portion, a shaft and an expandable member located at the distal portion, said expandable member having a first end and a second end and being constructed and arranged for expanding the outer diameter of said catheter from a contracted state to an expanded state; a radially expandable stent of generally cylindrical configuration positioned around said distal portion of said catheter around the expandable member, said stent having a contracted condition, being sized in the contracted condition to closely surround the catheter in the contracted state, and further being expandable to an expanded condition; removable stent protector means comprising a first removable sleeve in the region of the distal portion of the catheter positioned around the stent, said first sleeve further comprising a first end, and a second end, said first sleeve having a variable inner diameter to ease sliding the first sleeve over the balloon and stent, said stent protector means being removed prior to use of the stent delivery system and release of the stent by expansion of the balloon. 36. The stent delivery system of claim 35 wherein the expandable member and the first sleeve are of a material which resiliently deforms under radial pressure. 37. The stent delivery system of claim 35 wherein the stent is crimped to the expandable member for delivery. 38. The stent delivery system of claim 35 wherein the first sleeve is made of a low friction material. 39. The stent delivery system of claim 35 wherein the first sleeve has a lubricious coating thereon. 40. The stent delivery system of claim 35 wherein the first sleeve is a straight continuous tube. 41. The medical device of claim 40 wherein at least a portion of the continuous tube is dimpled. 42. The medical device of claim 41 wherein the continuous tube has round-like dimples. 43. The medical device of claim 41 wherein the continuous tube has helical grooved dimples. 44. The medical device of claim 41 wherein the entire continuous tube is dimpled. 45. The stent delivery system of claim 35 wherein the first end of the first sleeve further comprises a proximal flare. 46. The stent delivery system of claim 35 wherein said first sleeve has a slit extending therethrough. 47. The stent delivery system of claim 46 wherein the slit is a longitudinal slit extending from the first end of the sleeve to the second end of the sleeve. 48. The stent delivery system of claim 46 wherein the slit is a spiral slit extending in a helical manner from the first end of the sleeve to the second end of the sleeve. 49. The medical device of claim 46 wherein the slit extends distally in a helical manner from the first end of the sleeve and defines a proximal spiral region, said sleeve further comprising a distal continuous tubular portion. 50. The medical device of claim 49 wherein the distal continuous tubular portion further comprises a dimpled region and a substantially smooth region. 51. The medical device of claim 50 wherein the dimples are round-like. 52. The medical device of claim 50 wherein the dimples are helical grooves. 53. The stent delivery system of claim 35 wherein the stent protector means further comprises a second removable sleeve having a first end and a second end, said second sleeve being positioned over the first sleeve and having a constrictive relationship with said first sleeve. 54. The stent delivery system of claim 53 wherein the distal portion of the catheter further comprises at least one dam, over which the expandable member extends, and wherein when the first sleeve is compressed by the second (outer) sleeve, the first sleeve has an inner diameter less than or equal to the outer profile of the expandable member over the at least one dam. 55. The stent delivery system of claim 54 wherein said at least one dam comprises a proximal dam and a distal dam spaced a predetermined distance apart, said dams having an equal outer diameter, the expandable member is a balloon located over and between said proximal and distal dam, the stent is located over the balloon and between the dams and the first sleeve has a length approximately equal to that of the stent. 56. The stent delivery system of claim 53 wherein the first sleeve and the second sleeve are made of a low friction material. 57. The stent delivery system of claim 53 wherein said first sleeve is coextruded and has a high friction inner diameter and a low friction outer diameter, whereby the first sleeve will not slip when the second sleeve is pushed thereon. 58. The stent delivery system of claim 53 wherein at least one of said first sleeve and second sleeve is a continuous tube. 59. The stent delivery system of claim 58 wherein at least a portion of said at least one continuous tube is dimpled. 60. The stent delivery system of claim 59 wherein the entire continuous tube is dimpled. 61. The stent delivery system of claim 59 wherein the dimples are round-like. 62. The stent delivery system of claim 59 wherein the dimples are helical grooves. 63. The stent delivery system of claim 59 having round-like dimples and helical dimples. 64. The stent delivery system of claim 58 wherein said at least one straight tube further comprises a proximal flare. 65. The stent delivery system of claim 53 wherein at least one of said first and second sleeves has a slit extending therethrough. 66. The stent delivery system of claim 65 wherein the slit is a longitudinal slit extending from the first end of the sleeve to the second end of the sleeve. 67. The stent delivery system of claim 65 wherein the slit is a spiral slit extending in a helical manner from the first end of the sleeve to the second end of the sleeve. 68. The stent delivery system of claim 65 wherein the slit extends distally in a helical manner from the first end of the sleeve and defines a proximal spiral region, said sleeve further comprising a distal continuous tubular portion. 69. The stent delivery system of claim 68 wherein at least a portion of the distal continuous tubular portion further comprises a dimpled region. 70. The stent delivery system of claim 69 wherein the dimpled region has round-like dimples. 71. The stent delivery system of claim 69 wherein the dimpled region has dimpled helical grooves. 72. The stent delivery system of claim 53 wherein the expandable member comprises a balloon made of an elastomeric material. 73. The stent delivery system of claim 53 wherein the first sleeve further comprises removal means extending from the second end thereof, said removal means comprising a tail. 74. A system for intraluminal delivery of a stent comprising: a balloon catheter comprising a shaft, a balloon associated with a distal portion of the shaft for receiving a stent, the shaft further comprising at least one dam and an inflation lumen associated with the balloon for inflation thereof; stent retaining means comprising a first removable sleeve for positioning around a stent and a second removable sleeve for positioning around the first sleeve such that the first sleeve is compressed by the second sleeve to an inner diameter less than or equal to the outer diameter of the at least one dams, said first and second sleeves being removed prior to use of the delivery system and release of a stent mounted to the catheter for delivery thereof by expansion of the balloon. 75. The system of claim 74 wherein the distal portion of the catheter comprises a proximal dam and a distal dam spaced a predetermined distance apart, said dams having an equal outer diameter, the balloon portion is located over and between the dams, and the stent is located over the balloon and between the dams. 76. The system of claim 74 wherein: the first sleeve is made of a lubricious material and further comprises a first end, a second end and a slit extending therethrough, said slit providing a variable inner diameter to ease sliding the first sleeve over a stent mounted on the balloon; and the second sleeve has an inner diameter, prior to mounting on the catheter, less than the outer diameter of the first sleeve prior to mounting on the catheter. 77. The system of claim 76 wherein the slit is a longitudinal slit. 78. The system of claim 76 wherein the slit is in a spiral configuration. 79. The system of claim 76 wherein the slit extends distally in a helical manner from the first end of the sleeve and defines a proximal spiral region, said sleeve further comprising a distal continuous tubular portion. 80. The system of claim 79 wherein at least a portion of distal continuous tubular portion is dimpled. 81. The system of claim 80 wherein said dimpled portion has round-like dimples. 82. The system of claim 80 wherein said dimpled portion has dimpled helical grooves. 83. The system of claim 76 wherein one of said first and second sleeves comprises a coiled flat wire, spring wound without a gap between the coils thereof. 84. The system of claim 76 wherein at least one of said sleeves comprises a polymeric tube having a first end, a second end, and a variable inner diameter, wherein at least one of said ends is flared, said tube having a slit extending from the first end to the second end, enabling said sleeve to be peeled off the catheter.

Inventors: EIDENSCHINK TRACEE E J, ELLIS LOUIS G, HANSON SCOTT M, HOLMAN THOMAS J, LORENTZEN CORNELIUS LINDA R, OLSON GREGORY S, TRAXLER RICHARD J, WILLIAMS SONJA J K, EIDENSCHINK, TRACEE, E., J., ELLIS, LOUIS, G., HANSON, SCOTT, M., HOLMAN, THOMAS, J., LORENTZEN CORNELIUS, LINDA, R., OLSON, GREGORY, S., TRAXLER, RICHARD, J., WILLIAMS, SONJA, J., K.
Applicants: SCIMED LIFE SYSTEMS INC, SCIMED LIFE SYSTEMS, INC.
Application year: 1998
Main classification: A61M29
IPC codes: A61F2, A61M25, A61M29