Patent Publication Number: US-9427557-B2

Title: Occlusion crossing device and method

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/178,425, filed Jul. 13, 2008, the entire disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosure is directed to elongated medical devices. More particularly, the disclosure is directed to balloon catheters and stent delivery devices for positioning a balloon and/or stent across a lesion of a blood vessel. 
     BACKGROUND 
     Millions of people suffer from thrombotic or atherosclerotic occlusions in blood vessels. Such occlusions restrict the blood flow through the vessel, and if left untreated, these occlusions may lead to a heart attack, or even death. A variety of available medical devices have been manufactured to treat occlusions in a blood vessel within a patient&#39;s body. For example, directional atherectomy and percutaneous translumenal coronary angioplasty (PTCA) with or without stent deployment have been found useful in treating patients with coronary occlusions, as well as occlusions of other vessels. Angioplasty utilizes an expandable balloon on a catheter which exerts a mechanical force on the vascular wall to enlarge the luminal diameter of an occluded vessel. In some medical procedures, a prosthetic device, such as a stent, is expanded within the blood vessel at the location of the occlusion in order to provide patency/integrity through the lumen of the blood vessel at the location of the occlusion. 
     Some vascular occlusions can be difficult or impossible to cross with existing angioplasty catheters and stent delivery systems. For example, in some instances the occlusion may extend substantially across the lumen of the blood vessel, or may even completely block the lumen of the blood vessel in some cases. In such instances, it may be difficult or impossible to advance a conventional catheter, such as the balloon of a conventional angioplasty catheter (i.e., POBA) and/or a stent of a stent delivery system, across the occlusion. 
     Therefore, a need remains to provide a catheter system to aid in crossing vascular occlusions with a balloon and/or a stent of a balloon catheter. Namely, it would be desirable to provide a means for facilitating advancement of a balloon, stent and/or other working element of a catheter through the restricted opening of a vascular occlusion of a blood vessel. 
     SUMMARY 
     The disclosure is directed to several alternative designs, materials and methods of manufacturing medical device structures and assemblies. 
     Accordingly, one illustrative embodiment is a stent delivery catheter for positioning a stent across a lesion of a blood vessel. The catheter includes an inflation balloon coupled to a distal region of the elongate shaft of the catheter and a stent loaded on the inflation balloon. The inflation balloon includes a proximal waist, a distal waist and a central region between the proximal waist and the distal waist. The catheter may also include an occlusion balloon having a proximal waist secured to the elongate shaft and a distal waist secured to the elongate shaft. The occlusion balloon includes a first folded-over portion extending distal of the distal waist to a distalmost extent of the occlusion balloon and a second folded-over portion extending proximal of the proximal waist to a proximalmost extent of the occlusion balloon. The catheter further includes a fluid discharge port located distal of the occlusion balloon for discharging a fluid exterior of the elongate shaft. The fluid may be a lubricious fluid discharged toward the stent to facilitate advancing the stent across an occlusion. 
     Another illustrative embodiment is a stent delivery catheter for positioning a stent across a lesion of a blood vessel. The catheter includes an inflation balloon coupled to a distal region of the elongate shaft of the catheter and a stent loaded on the inflation balloon. The inflation balloon includes a proximal waist, a distal waist and a central region between the proximal waist and the distal waist. The catheter may also include an occlusion balloon having a proximal waist secured to the elongate shaft and a distal waist secured to the elongate shaft. The occlusion balloon includes a first portion extending distal of the distal waist to a distalmost extent of the occlusion balloon which is not bonded to the elongate shaft, and a second portion extending proximal of the proximal waist to a proximalmost extent of the occlusion balloon which is not bonded to the elongate shaft. The catheter further includes a fluid discharge port located distal of the occlusion balloon for discharging a fluid exterior of the elongate shaft. 
     Another illustrative embodiment is a stent delivery catheter for positioning a stent across a lesion of a blood vessel. The catheter includes an inflation balloon coupled to a distal region of the elongate shaft of the catheter and a stent loaded on the inflation balloon. The inflation balloon includes a proximal waist, a distal waist and a central region between the proximal waist and the distal waist. The catheter may also include an occlusion member configured to expand across a lumen of a blood vessel. The occlusion member is disposed around the elongate shaft at a location proximal of the inflation balloon. The elongate shaft is longitudinally translatable relative to the occlusion member. The catheter further includes a fluid discharge port located distal of the occlusion balloon for discharging a fluid exterior of the elongate shaft. 
     Another illustrative embodiment is a method of crossing a lesion within a blood vessel with a stent delivery catheter. The method includes providing a stent delivery catheter including an elongate shaft, an inflation balloon, a stent disposed over the inflation balloon, an occlusion balloon, and a fluid discharge port. A guidewire is advanced through a lumen of a blood vessel and across a lesion within the blood vessel. The stent delivery catheter is then advanced over the guidewire such that the inflation balloon and stent are located just proximal of the lesion. The occlusion balloon is then inflated such that the occlusion balloon extends across the lumen of the blood vessel. A lubricious fluid is expelled out the fluid discharge port into the blood vessel. The inflation balloon and stent may then be further advanced across the lesion while retaining the occlusion balloon at least partially inflated. With the stent across the lesion, the inflation balloon may be inflated, thereby expanding the stent within the lumen of the blood vessel at the lesion. Prior to withdrawing the catheter from the blood vessel, the inflation balloon and the occlusion balloon may be at least partially deflated. 
     Yet another illustrative embodiment is a method of crossing a lesion within a blood vessel with a stent delivery catheter. The method includes providing a stent delivery catheter including an elongate shaft, an inflation balloon, a stent disposed over the inflation balloon, an occlusion device, and a fluid discharge port. A guidewire is advanced through a lumen of a blood vessel and across a lesion within the blood vessel. The stent delivery catheter is then advanced over the guidewire such that the inflation balloon and stent are located just proximal of the lesion. The occlusion device is then expanded such that the occlusion device extends across the lumen of the blood vessel. A lubricious fluid is expelled out the fluid discharge port into the blood vessel. The inflation balloon and stent may then be further advanced across the lesion while retaining the occlusion device at least partially expanded within the blood vessel. With the stent across the lesion, the inflation balloon may be inflated, thereby expanding the stent within the lumen of the blood vessel at the lesion. Prior to withdrawing the catheter from the blood vessel, the inflation balloon may be at least partially deflated and the occlusion device may be at least partially collapsed. 
     The above summary of some example embodiments is not intended to describe each disclosed embodiment or every implementation of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which: 
         FIG. 1  is a plan view of an exemplary stent delivery catheter for crossing an occlusion within a blood vessel; 
         FIG. 1A  is a cross-sectional view of the elongate shaft of  FIG. 1  taken along line  1 A- 1 A proximal of the occlusion balloon; 
         FIGS. 2 through 4  are partial cross-sectional views of a distal portion of the stent delivery catheter depicting rolling movement of the occlusion balloon; 
         FIG. 5  is a perspective view of a portion of the catheter of  FIG. 1  showing the fluid discharge port; 
         FIGS. 6A through 6G  illustrate an exemplary method of placing a stent across an occlusion in a blood vessel utilizing the stent delivery catheter of  FIG. 1 ; 
         FIG. 7  illustrates the distal portion of another exemplary stent delivery catheter; 
         FIG. 8  illustrates the distal portion of another exemplary stent delivery catheter; 
         FIGS. 9A and 9B  depict another exemplary stent delivery catheter with an elongate shaft translatable through an occlusion member; and 
         FIGS. 10A through 10C  depict another exemplary stent delivery catheter with an elongate shaft translatable through an occlusion member. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
     DETAILED DESCRIPTION 
     For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. 
     All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure. 
     The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
     Although some suitable dimensions ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed. 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary. 
     Now referring to  FIG. 1 , an exemplary medical device, shown as a stent delivery catheter system  10 , is illustrated. The stent delivery catheter  10  includes an elongate shaft  12  extending from a proximal end (not shown) to a distal end  14 . The elongate shaft  12  includes a distal region  16  proximate the distal end  14  of the elongate shaft  12 . An inflation balloon  20  may be secured to the elongate shaft  12  along the distal region  16  of the elongate shaft  12 . For instance, a proximal waist  22  of the inflation balloon  20  may be secured to the elongate shaft  12  and/or a distal waist  24  of the inflation balloon  20  may be secured to the elongate shaft  12 . In some embodiments, the proximal waist  22  and/or the distal waist  24  of the inflation balloon  20  may be bonded, such as adhesively bonded or thermally bonded, to the elongate shaft  12 . 
     In some embodiments, the elongate shaft  12  may be a multi-lumen elongate member, such as an extruded multi-lumen elongate member. In other embodiments, the elongate shaft  12  may include an outer tubular member and an inner tubular member disposed within the lumen of the outer tubular member. In such an embodiment, the proximal waist  22  of the inflation balloon  20  may be secured to the outer tubular member and the distal waist  24  of the inflation balloon  20  may be secured to the inner tubular member. 
     A stent  18 , or other prosthetic device, may be loaded onto the inflation balloon  20 . For instance, the stent  18  may be disposed on and extend around the circumference of a central region of the inflation balloon  20 . Although illustrated as a stent  18 , any number of devices that may be introduced subcutaneously, percutaneously or surgically may be loaded onto the inflation balloon  20 . The stent  18  may be any desired stent. Some exemplary stents are disclosed in U.S. Pat. Nos. 6,730,117; 6,776,793; 6,945,993 and 6,981,986, each of which are incorporated herein by reference. In some embodiments, the stent  18  may have a longitudinal length of about 8 to about 40 millimeters, about 10 to about 20 millimeters, about 12 to about 18 millimeters, or about 14 to about 16 millimeters. 
     The stent delivery catheter  10  may include a fluid discharge port  26  at a location in the distal region  16  of the elongate shaft  12 . For example, the fluid discharge port  26  may be located proximal of the inflation balloon  20 . However, in other embodiments, the fluid discharge port  26  may be located distal of the inflation balloon  20 . 
     The fluid discharge port  26  may be configured to discharge a fluid, such as a lubricious fluid or a therapeutic agent, out of the elongate shaft  12  and into the lumen of a blood vessel during delivery of the stent  18  to a target location of a patient&#39;s body. In some embodiments, the fluid discharge port  26  may be configured such that a fluid expelled from the fluid discharge port  26  is directed toward the stent  18 , toward the distal end  14  of the stent delivery catheter  10 , and/or toward an occlusion blocking advancement of the stent delivery catheter  10  further distally through a blood vessel. 
     An occlusion member, shown as an occlusion balloon  30 , may be located proximal of the fluid discharge port  26 . For example, the occlusion balloon  30  may be secured to the elongate shaft  12  at a location proximal of the inflation balloon  20  and the fluid discharge port  26 . In some embodiments, the fluid discharge port  26  may be located intermediate the inflation balloon  20  and the occlusion balloon  30 . The occlusion balloon  30  may include a proximal waist  32  secured to the elongate shaft  12  and/or a distal waist  34  secured to the elongate shaft  12 . In some embodiments, the proximal waist  32  and/or the distal waist  34  of the occlusion balloon  30  may be bonded, such as adhesively bonded or thermally bonded, to the elongate shaft  12 . 
       FIG. 1A  is a cross-sectional view of the elongate shaft  12  at a location proximal of the occlusion balloon  30  taken along line  1 A- 1 A of  FIG. 1 . The elongate shaft  12  may include a plurality of lumens. For example, the elongate shaft  12  may include a guidewire lumen  45  for receiving a guidewire. The guidewire lumen  45  may extend from the distal end  14  of the elongate shaft  12  to a location proximal of the inflation balloon  20  and/or the occlusion balloon  30 . In some instances, the guidewire lumen  45  may extend from the distal end  14  of the elongate shaft  12  to the proximal end of the elongate shaft  12 , while in other instances, the guidewire lumen  45  may extend proximally from the distal end  14  of the elongate shaft  12  to a guidewire exit port located distal of the proximal end of the elongate shaft  12 . 
     Additionally, the elongate shaft  12  may include a first inflation lumen  40  in fluid communication with the interior of the inflation balloon  20  for advancing an inflation fluid distally through the elongate shaft  12  to the inflation balloon  20 . The elongate shaft  12  may also include a second inflation lumen  42  in fluid communication with the interior of the occlusion balloon  30  for advancing an inflation fluid distally through the elongate shaft  12  to the occlusion balloon  30 . Thus, it can be seen that the inflation balloon  20  and the occlusion balloon  30  may each be inflated/deflated independently of inflation/deflation of the other of the inflation balloon  20  and the occlusion balloon  30 . 
     The elongate shaft  12  may further include a fluid injection lumen  44  in fluid communication with the fluid discharge port  26 . During use, a fluid, such as a lubricious fluid or a therapeutic agent, may be injected from exterior of the body of a patient through the elongate shaft  12  via the fluid injection lumen  44  to the fluid discharge port  26 . Thus, a fluid, such as a lubricious fluid or a therapeutic agent, may be expelled from the fluid discharge port  26  into a blood vessel of a patient while the stent delivery catheter  10  is located within a blood vessel of a patient. 
     Although the elongate shaft  12  is shown including a guidewire lumen  45  centrally located between three additional lumens, one of skill in the art would understand that the elongate shaft  12  may include any desired number and arrangement of lumens to accomplish a desired function. 
     Now referring to  FIG. 2 , the occlusion balloon  30  will be further described. The occlusion balloon  30  is shown in its expanded or inflated state in  FIG. 2 . The occlusion balloon  30  may be formed of a balloon wall  36  extending between the proximal waist  32  and the distal waist  34  of the occlusion balloon  30 . The occlusion balloon  30  may have a longitudinal length L measured from a proximalmost extent  38  of the occlusion balloon  30  to a distalmost extent  39  of the occlusion balloon  30 . 
     In some embodiments, the occlusion balloon  30  may be formed of a non-compliant material, such as a non-compliant polymeric material. Thus, when inflated, the occlusion balloon  30  will not continue to enlarge in size and/or shape beyond a predetermined expanded size and shape as the fluid pressure within the occlusion balloon  30  continues to increase. In other embodiments, the occlusion balloon  30  may be formed of a compliant material, such as an elastomeric polymer. In some embodiments, the diameter of the occlusion balloon  30  may be sized smaller than the diameter of the inflation balloon  20 . For example, in some embodiments, the diameter of the occlusion balloon  30  when inflated may be chosen to be about 10%, about 15%, about 20%, about 25% or about 30% less than the diameter of the inflation balloon  20  when inflated. 
     As shown in  FIG. 2 , the proximal waist  32  and the distal waist  34  of the occlusion balloon  30  may be secured to the elongate shaft  12  at locations underneath the occlusion balloon  30 . The distance between the proximal waist  32  and the distal waist  34  is denoted as length Z in  FIG. 2 . Furthermore, the longitudinal length of the proximal waist  32  (e.g., the portion of the occlusion balloon  30  bonded to the elongate shaft  12 ) is denoted as length X 1 , and the longitudinal length of the distal waist  34  (e.g., the portion of the occlusion balloon  30  bonded to the elongate shaft  12 ) is denoted as length X 2 . 
     In some embodiments, the length Z between the proximal waist  32  and the distal waist  34  may be less than the length L of the occlusion balloon  30 . For instance, in some embodiments the length L of the occlusion balloon  30  may be about 1.5 times or more, about 2 times or more, about 2.5 times or more, about 3 times or more, about 3.5 times or more, about 4 times or more, about 4.5 times or more, or about 5 times or more of the length Z between the proximal waist  32  and the distal waist  34  of the occlusion balloon  30 . 
     The occlusion balloon  30  may include a first folded-over (i.e., doubled-over) portion  41  located proximal of the proximal waist  32  and a second folded-over (i.e., doubled-over) portion  43  located distal of the distal waist  34 . The first folded-over portion  41  includes a first layer  46  of the occlusion balloon wall  36  and a second layer  47  of the occlusion balloon wall  36  located radially outward from the first layer  46  of the occlusion balloon wall  36 . The second folded-over portion  43  includes a first layer  48  of the occlusion balloon wall  36  and a second layer  49  of the occlusion balloon wall  36  located radially outward from the first layer  48  of the occlusion balloon wall  36 . 
     The first layer  46  of the first folded-over portion  41  may extend proximal of the proximal balloon waist  32  to the proximalmost extent  38  of the occlusion balloon  30 , and the first layer  48  of the second folded-over portion  43  may extend distal of the distal balloon waist  34  to the distalmost extent  39  of the occlusion balloon  30 . 
     The second layer  47  of the first folded-over portion  41  may extend distally from the proximalmost extent  38  of the occlusion balloon  30  at a position radially outward from the first layer  46 , and the second layer  49  of the second folded-over portion  43  may extend proximally from the distalmost extent  39  of the occlusion balloon  30  at a position radially outward from the first layer  48 . 
     The first layer  46  of the first folded-over portion  41  may extend circumferentially around the circumference of the elongate shaft  12 , and the second layer  47  of the first folded-over portion  41  may extend circumferentially around the circumference of the elongate shaft  12  radially outward of the first layer  46 . Furthermore, the first layer  48  of the second folded-over portion  43  may extend circumferentially around the circumference of the elongate shaft  12 , and the second layer  49  of the second folded-over portion  43  may extend circumferentially around the circumference of the elongate shaft  12  radially outward of the first layer  48 . 
     The wall  36  of the occlusion balloon  30  has an exterior surface  50  and an interior surface  52 . As described herein, the exterior surface  50  is the surface of the wall  36  of the occlusion balloon  30  which may come into contact with blood within a blood vessel and/or the inner surface (e.g., intima) of a blood vessel during use. As described herein, the interior surface  52  is the surface of the wall  36  of the occlusion balloon  30  which may come into contact with an inflation fluid used to inflate the occlusion balloon  30  during use. The exterior surface  50  of the first layer  46  of the first folded-over portion  41  may face the exterior surface  54  of the elongate shaft  12 . However, the exterior surface  50  of the first layer  46  may not be secured to the exterior surface  54  of the elongate shaft  12 . Thus, the first layer  46  of the first folded-over portion  41  may extend along the exterior surface  54  of the elongate shaft  12 , yet not be bonded to the elongate shaft  12 . Likewise, the exterior surface  50  of the first layer  48  of the second folded-over portion  43  may face the exterior surface  54  of the elongate shaft  12 . However, the exterior surface  50  of the first layer  48  may not be secured to the exterior surface  54  of the elongate shaft  12 . Thus, the first layer  48  of the second folded-over portion  43  may extend along the exterior surface  54  of the elongate shaft  12 , yet not be bonded to the elongate shaft  12 . 
     The longitudinal length of the first folded-over portion  41  proximate the proximalmost extent  38  of the occlusion balloon  30  is denoted as Y 1  in  FIG. 2  and the longitudinal length of the second folded over portion  43  proximate the distalmost extent  39  of the occlusion balloon  30  is denoted as Y 2  in  FIG. 2 . In some embodiments, the sum of the longitudinal lengths of the first folded-over portion  41  and the second folded-over portion  43  is equal to or greater than the length of the stent  18 . For instance, in some embodiments the sum of the longitudinal lengths of the first folded-over portion  41  and the second folded-over portion  43  may be about 1 or more times, about 1.1 or more times, 1.2 or more times, 1.3 or more times, 1.4 or more times, 1.5 or more times, 2 or more times, or 2.5 or more times the length of the stent  18 . 
     The configuration of the occlusion balloon  30  allows the occlusion balloon  30  to roll upon itself while the occlusion balloon  30  is at least partially inflated within a blood vessel. This is demonstrated in  FIG. 3 . As shown in  FIG. 3 , distal advancement of the elongate shaft  12  while the occlusion balloon  30  is at least partially inflated and in contact with the intima of a blood vessel causes the occlusion balloon  30  to roll upon itself. In other words, as the elongate shaft  12  is advanced distally (shown by arrows in  FIG. 3 ), a portion of the first layer  48  of the second folded-over portion  43  of the occlusion balloon  30  rolls away from the exterior surface  54  of the elongate shaft  12  and becomes a portion of the second layer  49  of the second folded-over portion  43  of the elongate shaft  12 . Similarly, a portion of the second layer  47  of the first folded-over portion  41  of the occlusion balloon  30  rolls toward the exterior surface  54  of the elongate shaft  12  and becomes a portion of the first layer  46  of the first folded over portion  41 . This movement of the balloon wall  36  is depicted by the arrows interior of the occlusion balloon  30  shown in  FIG. 3 . 
     Such rolling motion increases the length of the first folded-over portion  41  from the length Y 1  shown in  FIG. 2  to the length Y 1 ′ shown in  FIG. 3 . Similarly, such rolling motion reduces the length of the second folded-over portion  43  from the length Y 2  shown in  FIG. 2  to the length Y 2 ′ shown in  FIG. 3 . Although the length Y 1 ′ of the first folded-over portion  41  and the length Y 2 ′ of the second folded-over portion  43  of the occlusion balloon  30  are changed, it is noted that the sum of the length Y 1 ′ of the first folded-over portion  41  and the length Y 2 ′ of the second folded-over portion  43  may remain the same, as the occlusion balloon  30  undergoes rolling action. Additionally, the overall longitudinal length L of the occlusion balloon  30  may remain unchanged throughout the rolling motion. Furthermore, as the occlusion balloon  30  is rolled upon itself as the elongate shaft  12  is advanced distally, the distance between the distal extent  39  of the occlusion balloon  30  and the fluid discharge port  26  increases. 
       FIG. 4  shows the elongate shaft  12  advanced further distally relative to the occlusion balloon  30 . As shown in  FIG. 4 , further distal advancement of the elongate shaft  12  while the occlusion balloon  30  is at least partially inflated and in contact with the intima of a blood vessel causes the occlusion balloon  30  to further roll upon itself. In other words, as the elongate shaft  12  is further advanced distally (from the position shown in  FIG. 3 ), an additional portion of the first layer  48  of the second folded-over portion  43  of the occlusion balloon  30  rolls away from the exterior surface  54  of the elongate shaft  12  and becomes a portion of the second layer  49  of the second folded-over portion  43  of the elongate shaft  12 . Similarly, an additional portion of the second layer  47  of the first folded-over portion  41  of the occlusion balloon  30  rolls toward the exterior surface  54  of the elongate shaft  12  and becomes a portion of the first layer  46  of the first folded over portion  41 . 
     Such rolling motion further increases the length of the first folded-over portion  41  from the length Y 1 ′ shown in  FIG. 3  to the length Y 1 ″ shown in  FIG. 4 . Similarly, such rolling motion further reduces the length of the second folded-over portion  43  from the length Y 2 ′ shown in  FIG. 3  to the length Y 2 ″ shown in  FIG. 4 . Although the length Y 1 ″ of the first folded-over portion  41  and the length Y 2 ″ of the second folded-over portion  43  of the occlusion balloon  30  are changed, it is noted that the sum of the length Y 1 ″ of the first folded-over portion  41  and the length Y 2 ″ of the second folded-over portion  43  may remain the same, as the occlusion balloon  30  undergoes further rolling action. As the occlusion balloon  30  is further rolled upon itself as the elongate shaft  12  is advanced distally, the distance between the distal extent  39  of the occlusion balloon  30  and the fluid discharge port  26  further increases. 
     The elongate shaft  12  may include one or more, or a plurality of inflation ports  56  fluidly connecting the second inflation lumen  42  of the elongate shaft  12  with the interior of the occlusion balloon  30 . The inflation port(s)  56  allow an inflation fluid to enter the interior of the occlusion balloon  30  during inflation of the occlusion balloon  30  from the second inflation lumen  42 . 
       FIG. 5  is a perspective view further illustrating one possible configuration of the fluid discharge port  26 . As shown in  FIG. 5 , the elongate shaft  12  may include a proximal section  58  and a distal section  60  extending distal of the proximal section  58 . The distal section  60  may include the guidewire lumen  45  and the first inflation lumen  40  which is in fluid communication with the interior of the inflation balloon  20  of the stent delivery catheter  10 . In other embodiments, such as embodiments in which the fluid discharge port  26  is located distal of the inflation balloon  20 , the distal section  60  of the elongate shaft  12  may include one or more additional lumens. 
     The fluid discharge port  26  may be located at the distal end of the proximal section  58 . For example, in some embodiments the fluid discharge port  26  may be a conical or funnel-shaped portion of the proximal section  58  concentrically disposed around the distal section  60  extending distally from the proximal section  58 . The opening  62  of the fluid discharge port  26  may be in fluid communication with the fluid injection lumen  44  of the elongate shaft  12 . The conical nature of the fluid discharge port  26  may allow a fluid, such as a lubricious fluid or a therapeutic agent, to be expelled from the fluid discharge port  26  substantially around the entire circumference of the distal section  60 . Thus, in such an embodiment fluid discharged from the fluid discharge port  26  may be expelled radially outward from the shaft  12  in all radial directions. 
       FIGS. 6A through 6G  illustrate one exemplary method of using the stent delivery catheter  10  during a medical procedure. For example, the stent delivery catheter  10  may be used to place a stent  18  across an occlusion  102 , such as a thrombotic or atherosclerotic occlusion, in a blood vessel  100 . 
     As shown in  FIG. 6A , a guidewire  80  may first be advanced through the lumen  104  of the blood vessel  100  such that the guidewire  80  is positioned across the occlusion  102 . In some embodiments the guidewire  80  may be passed through an opening  106  extending through the occlusion  102 . In other embodiments, the guidewire  80 , or another medical device, may form an opening  106  through the occlusion  102 . The guidewire  80  may provide a pathway for advancing additional medical devices through the blood vessel  100  to a location proximate the occlusion  102 . 
     The stent delivery catheter  10  may then be advanced along the guidewire  80  to a location proximate the occlusion  102 , as shown in  FIG. 6B . For instance, the guidewire  80  may be inserted through the guidewire lumen  45  of the stent delivery catheter  10 , and the stent delivery catheter  10  advanced distally thereon. In the case of an occlusion  102  substantially obstructing the lumen  104  of the blood vessel  100 , the stent  18  positioned on the stent delivery catheter  10  may not be able to be advanced through the opening  106  and across the occlusion  102  without aid. As shown in  FIG. 6B , the presence of the occlusion  102  across the lumen  104  of the blood vessel  100  may halt distal advancement of the stent delivery catheter  10  while the stent  18  of the stent delivery catheter remains proximal of the occlusion  102 . In other words, the opening  106  through the occlusion  102  may be too small to allow the stent  18  to pass through the opening  106  unimpeded. 
     In applications in which the occlusion  102  blocks free advancement of the stent  18  across the occlusion  102 , once the stent  18 , loaded on the inflation balloon  20  of the stent delivery catheter  10 , is located proximal of the occlusion  102 , the occlusion balloon  30  may be inflated within the blood vessel  100 , as shown in  FIG. 6C . Inflation of the occlusion balloon  30  causes the exterior surface  50  of the wall  36  of the occlusion balloon  30  to contact the intima (i.e., inner surface) of the blood vessel  100 . Thus when inflated, the occlusion balloon  30  may extend across the lumen  104  of the blood vessel  100 . In some embodiments, the occlusion balloon  30  may be inflated to about 2 to about 6 Atmospheres (ATM), or about 2 to about 4 ATM, for example. 
     In some embodiments, inflation of the occlusion balloon  30  may also help center the elongate shaft  12  and/or the stent  18  of the stent delivery catheter  10  within the lumen  104  of the blood vessel  100 . For instance, inflation of the occlusion balloon  30  may align the stent  18  at the center of the lumen  104  of the blood vessel  100 . 
     Inflation of the occlusion balloon  30  within the lumen  104  of the blood vessel  100  may substantially occlude the lumen  104  of the blood vessel  100 , preventing blood flow across the location in which the occlusion balloon  30  is inflated. For example, in embodiments in which the occlusion balloon  30  is placed in the upstream direction of blood flow past the occlusion  102 , the occlusion balloon  30  may disrupt blood flow across the occlusion balloon  30  toward the occlusion  102 . 
     Once the occlusion balloon  30  is inflated within the blood vessel  100 , a fluid, such as a lubricious fluid or a therapeutic agent, (shown by arrows  90 ) may be expelled from the fluid discharge port  26  into the lumen  104  of the blood vessel  100 . The presence of the occlusion balloon  30  may help direct the fluid toward the stent  18  and/or toward the occlusion  102 . Furthermore, in some embodiments, such as embodiments in which the occlusion balloon  30  is placed in the upstream direction of blood flow past the occlusion  102 , expansion of the occlusion balloon  30  helps prevent the blood flow from disrupting discharge of the fluid  90  from the fluid discharge port  26  into the blood vessel  26  proximate the occlusion  102 . 
     One exemplary lubricious fluid which may be expelled from the fluid discharge port  26  is ROTAGLIDE®, a phospholipid emulsion, sold by Boston Scientific Scimed, Inc., Maple Grove, Minn. ROTAGLIDE® is a solution of olive oil, egg yolk phospholipids, glycerin, sodium deoxycholate, L-histidine, disodium EDTA, sodium hydroxide, and water. In some embodiments, other phospholipid emulsions, oil-in-water based emulsions, as well as other lubricious fluids may be used. 
     The lubricious fluid  90  may coat the surface of the stent  18  and/or the inflation balloon  20 , and/or may coat the surface of the opening  106  of the occlusion  102 . In some embodiments, the lubricious fluid  90  may form a lubricious layer or buffer between the stent  18  and the surface of the opening  106  of the occlusion  102 . Therefore, the expulsion of the lubricious fluid  90  may greatly reduce the coefficient of friction between the stent  18  and the surface of the opening  106  through the occlusion  102 . For example, the lubricious fluid  90  may reduce the coefficient of friction at the interface between the stent  18  and the surface of the opening  106  of the occlusion  102  to about 0.14 or less, about 0.12 or less, about 0.10 or less, about 0.08 or less, about 0.06 or less, or about 0.04 or less in some embodiments. 
     In some embodiments, the lubricious fluid  90  expelled from the fluid discharge port  26  may act to expand the opening  106  of the occlusion  102 , as well. For instance, as shown by arrows  95  of  FIGS. 6C and 6D , the forces of the lubricious fluid  90  may act on the surface of the opening  106  of the occlusion  102  to radially enlarge the opening  106  through the occlusion  102 . Enlarging the opening  106  and/or reducing the coefficient of friction between the stent  18  and the surface of the opening  106  of the occlusion  102  may facilitate further advancement of the stent  18  and/or inflation balloon  20  through the opening  106  of the occlusion  102 . 
     As shown in  FIG. 6D , upon expelling the lubricious fluid  90  from the fluid discharge port  26  of the stent delivery catheter  10 , the stent  18  and/or the inflation balloon  20  may be further advanced through the opening  106  of the occlusion  102 . The stent  18  and/or inflation balloon  20  may be further advanced through the opening  106  of the occlusion  102  while the occlusion balloon  30  remains inflated, or at least partially inflated within the lumen  104  of the blood vessel  100 . With the occlusion balloon  30  inflated, or at least partially inflated, the occlusion balloon  30  may remain in contact with the intima or inner surface of the blood vessel  100  while the stent  18  and/or the inflation balloon  20  are further advanced across the occlusion  102 . 
     In some embodiments, while the stent  18  and/or inflation balloon  20  is further advanced through the opening  106  of the occlusion  102 , the lubricious fluid  90  may be continuously expelled from the fluid discharge port  26 . In other words, in some embodiments the lubricious fluid  90  may be continuously discharged from the fluid discharge port  26  while the stent  18  and/or inflation balloon  20  is further advanced through the opening  106  of the occlusion  102 . The lubricious fluid  90  may continue to provide a lubricious barrier between the stent  18  and/or inflation balloon  20  and the inner surface of the opening  106  of the occlusion  102  as the stent  18  and/or inflation balloon  20  is advanced through the opening  106 . Additionally and/or alternatively, further discharge of the lubricious fluid  90  may further act on the occlusion  102  to slightly expand the opening  106  of the occlusion  102  as the stent  18  and/or inflation balloon  20  is further advanced through the opening  106 . 
     In other embodiments, while the stent  18  and/or inflation balloon  20  is further advanced through the opening  106  of the occlusion  102 , the lubricious fluid  90  may be expelled from the fluid discharge port  26  with periodic pulsations. In other words, in some embodiments the lubricious fluid  90  may be periodically discharged from the fluid discharge port  26  while the stent  18  and/or inflation balloon  20  is further advanced through the opening  106  of the occlusion  102 . The pulsations of the lubricious fluid  90  may continue to provide a lubricious barrier between the stent  18  and/or inflation balloon  20  and the inner surface of the opening  106  of the occlusion  102  and/or may further act on the occlusion  102  to slightly expand the opening  106  of the occlusion  102  as the stent  18  and/or inflation balloon  20  is further advanced through the opening  106  and across the occlusion  102 . 
     The configuration of the occlusion balloon  30  allows the elongate shaft  12  and the stent  18  and/or inflation balloon  20  to be advanced further distally within the blood vessel  100  while the occlusion balloon  30  is inflated, or at least partially inflated within the blood vessel  100  to occlude blood flow through the blood vessel  100 . As discussed above, further distal movement of the elongate shaft  12  while the occlusion balloon  30  is in contact with the intima or inner surface of the blood vessel  100  results in the occlusion balloon  30  rolling upon itself. This rolling action is illustrated in  FIGS. 2-4 , which show the proximal waist  32  and the distal waist  34  of the occlusion balloon  30  moving distally while the portion of the wall  36  of the occlusion balloon  30  in contact with the blood vessel  100  does not move longitudinally relative to the blood vessel  100  at the interface between the occlusion balloon  30  and the inner surface of the blood vessel  100 . 
     As can be seen by comparing the position of the occlusion balloon  30  shown in  FIG. 6C  with the position of the occlusion balloon  30  shown in  FIG. 6D , as the elongate shaft  12 , inflation balloon  20  and/or stent  18  are further advanced distally through the occlusion  102 , a portion of the exterior surface of the occlusion balloon  30  facing the exterior surface of the elongate shaft  12  moves into contact with the intima of the blood vessel  100 . Simultaneously, a portion of the exterior surface of the occlusion balloon  30  in contact with the intima of the blood vessel  100  loses contact with the intima of the blood vessel  100  and rolls toward the exterior surface of the elongate shaft  12 . 
     Through the rolling motion of the occlusion balloon  30 , the longitudinal length of the folded-over portion of the occlusion balloon  30  extending distally of the distal waist  34  decreases, while the longitudinal length of the folded-over portion of the occlusion balloon  30  extending proximally of the proximal waist  32  increases. The overall length of the occlusion balloon  30  from the distalmost extent of the occlusion balloon  30  to the proximalmost extent of the occlusion balloon  30  may remain the same throughout the rolling motion of the occlusion balloon  30 . 
     The occlusion balloon  30  may be configured such that the elongate shaft  12  of the stent delivery catheter  10  may be advanced distally through a blood vessel  100  at least the length of the stent  18  while the occlusion balloon  30  remains in contact with the inner surface of the blood vessel  100 . The rolling action of the occlusion balloon  30  without sliding the occlusion balloon  30  along the inner surface of the blood vessel  100  allows the elongate shaft  12 , inflation balloon  20  and/or stent  18  to be advanced distally through the blood vessel  100  while the occlusion balloon  30  is inflated, or at least partially inflated in the blood vessel  100  and in contact with the inner surface of the blood vessel  100  without harming the blood vessel  100 . 
     As shown in  FIG. 6E , once the stent  18  and/or inflation balloon  20  is positioned through the opening  106  at a desired location, the occlusion balloon  30  may be deflated and/or expulsion of the lubricious fluid  90  from the fluid discharge port  26  may be discontinued. With the stent  18  and/or inflation balloon  20  positioned across the occlusion  102 , the inflation balloon  20  may be inflated by injecting a pressurized fluid into the interior of the inflation balloon  20  from the first inflation lumen  40  of the elongate shaft  12 . As shown in  FIG. 6F , inflation of the inflation balloon  20  causes the opening  106  through the occlusion  102  to expand in order to open the passageway through the occlusion  102  in order to regain blood flow past the occlusion  102 . In embodiments in which a stent  18  is placed across the occlusion  102 , inflation of the inflation balloon  20  expands the stent  18  into contact with the occlusion  102 , opening the occlusion  102  to an enlarged diameter. The expanded stent  18  may help maintain the opening through the occlusion  102 , thus contributing to the patency and/or integrity of the blood vessel  100 . 
     With the stent  18  properly expanded within the blood vessel  100 , the inflation balloon  20  may be deflated, or at least partially deflated. The stent delivery catheter  10  may then be withdrawn proximally from the blood vessel  100 . Additionally, the guidewire  80  may also be withdrawn from the blood vessel  100  at the conclusion of the medical procedure. As shown in  FIG. 6G , at the completion of the medical procedure, the stent  18 , if used, may remain expanded across the occlusion  102 , enlarging the opening  106  through the occlusion  102 , thus improving blood flow through the blood vessel  100 . 
     Although the above method of regaining blood flow across an occlusion  102  in a blood vessel  100  includes implanting a stent  18  across the occlusion  102 , in some embodiments the catheter  10  may be used as a conventional angioplasty catheter (e.g., POBA) in which the inflation balloon  20  may be inflated to enlarge the opening through the occlusion  102  without the aid of a stent  18 . 
     Additionally, although the catheter  10  used in the above method of regaining blood flow across an occlusion  102  is discussed as including an occlusion balloon  30 , in other embodiments the catheter  10  may not include an occlusion balloon  30 . In such embodiments, a lubricious fluid  90  may be expelled from the fluid discharge port  26  toward the stent  18  and/or occlusion  102  without the need of occluding the vessel  100  with an occlusion balloon  30 . 
       FIG. 7  illustrates the distal region of another stent delivery catheter  210 . The stent delivery catheter  210  may include an elongate shaft  212  extending from a proximal end of the stent delivery catheter  210  to the distal end of the stent delivery catheter  210 . An inflation balloon  220  may be secured to the distal region of the elongate shaft  212 . For example, the proximal waist  222  of the inflation balloon  220  may be secured to the elongate shaft  212  and/or the distal waist  224  of the inflation balloon  220  may be secured to the elongate shaft  212 . In some embodiments the proximal waist  222  and/or the distal waist  224  may be bonded, such as adhesively or thermally bonded, to the elongate shaft  212 . 
     A stent  218 , or other prosthetic device, may be loaded onto the inflation balloon  220 . For instance, the stent  218  may be disposed on and extend around the circumference of a central region of the inflation balloon  220 . Although illustrated as a stent  218 , any number of devices that may be introduced subcutaneously, percutaneously or surgically may be loaded onto the inflation balloon  220 . 
     The stent delivery catheter  210  may also include an occlusion member, such as an occlusion balloon  230 , secured to the elongate shaft  212  at a location proximal of the inflation balloon  220 . The occlusion balloon  230  may be similar in construction, function and operation to that of the occlusion balloon  30  of the stent delivery catheter  10 . Thus, in the interest of brevity, similarities in the construction, function and operation of the occlusion balloon  230  with that of the occlusion balloon  30  will not be reiterated. 
     For example, the occlusion balloon  230  may include a proximal waist  232  secured to the elongate shaft  212  and a distal waist  234  secured to the elongate shaft  212 . The proximal waist  232  may be secured to the elongate shaft  212  at a location distal of the proximalmost extent of the occlusion balloon  230 . Additionally, the distal waist  234  may be secured to the elongate shaft  212  at a location proximal of the distalmost extent of the occlusion balloon  230 . The occlusion balloon  230  may include a first folded-over portion  241  and a second folded-over portion  243 . The first folded-over portion  241  may include a first layer of the occlusion balloon wall and a second layer of the occlusion balloon wall located radially outward from the first layer of the occlusion balloon wall. Similarly, the second folded-over portion  243  may include a first layer of the occlusion balloon wall and a second layer of the occlusion balloon wall located radially outward from the first layer of the occlusion balloon wall. 
     The occlusion balloon  230  may be configured to roll upon itself as the elongate shaft  212  is advanced through a blood vessel of a patient with the occlusion balloon  230  inflated, or at least partially inflated, and in contact with the inner surface of a blood vessel. 
     The stent delivery catheter  210  may include a fluid discharge port  226  at a location in the distal region of the elongate shaft  212 . For example, the fluid discharge port  226  may be located distal of the inflation balloon  220 . However, in other embodiments, the fluid discharge port  226  may be located proximal of the inflation balloon  220 . 
     The fluid discharge port  226  may be configured to discharge a fluid, such as a lubricious fluid, out of the elongate shaft  212  and into the lumen of a blood vessel during delivery of the stent  218  to a target location of a patient&#39;s body. In some embodiments the fluid discharge port  226  may be configured such that a fluid expelled from the fluid discharge port  226  is directed toward the stent  218 . 
     Similar to the fluid discharge port  26 , the fluid discharge port  226  may be a conical or funnel-shaped component concentrically disposed around the elongate shaft  212 . The opening of the fluid discharge port  226  may be in fluid communication with a fluid injection lumen of the elongate shaft  212 . The conical nature of the fluid discharge port  226  may allow a fluid, such as a lubricious fluid or a therapeutic agent, to be expelled from the fluid discharge port  226  substantially around the entire circumference of the stent  218 . Thus, in such an embodiment fluid discharged from the fluid discharge port  226  may be expelled radially outward from the shaft  212  in all radial directions. 
       FIG. 8  illustrates the distal region of yet another stent delivery catheter  310 . The stent delivery catheter  310  may include an elongate shaft  312  extending from a proximal end of the stent delivery catheter  310  to the distal end of the stent delivery catheter  310 . An inflation balloon  320  may be secured to the distal region of the elongate shaft  312 . For example, the proximal waist  322  of the inflation balloon  320  may be secured to the elongate shaft  312  and/or the distal waist  324  of the inflation balloon  320  may be secured to the elongate shaft  312 . In some embodiments, the proximal waist  322  and/or the distal waist  324  may be bonded, such as adhesively or thermally bonded, to the elongate shaft  312 . 
     A stent  318 , or other prosthetic device, may be loaded onto the inflation balloon  320 . For instance, the stent  318  may be disposed on and extend around the circumference of a central region of the inflation balloon  320 . Although illustrated as a stent  318 , any number of devices that may be introduced subcutaneously, percutaneously or surgically may be loaded onto the inflation balloon  320 . 
     The stent delivery catheter  310  may also include an occlusion member, such as an occlusion balloon  330 , secured to the elongate shaft  312  at a location proximal of the inflation balloon  320 . The occlusion balloon  330  may be similar in construction, function and operation to that of the occlusion balloon  30  of the stent delivery catheter  10 . Thus, in the interest of brevity, similarities in the construction, function and operation of the occlusion balloon  330  with that of the occlusion balloon  30  will not be reiterated. 
     For example, the occlusion balloon  330  may include a proximal waist  332  secured to the elongate shaft  312  and a distal waist  334  secured to the elongate shaft  312 . The proximal waist  332  may be secured to the elongate shaft  312  at a location distal of the proximalmost extent of the occlusion balloon  330 . Additionally, the distal waist  334  may be secured to the elongate shaft  312  at a location proximal of the distalmost extent of the occlusion balloon  330 . The occlusion balloon  330  may include a first folded-over portion  341  and a second folded-over portion  343 . The first folded-over portion  341  may include a first layer of the occlusion balloon wall and a second layer of the occlusion balloon wall located radially outward from the first layer of the occlusion balloon wall. Similarly, the second folded-over portion  343  may include a first layer of the occlusion balloon wall and a second layer of the occlusion balloon wall located radially outward from the first layer of the occlusion balloon wall. 
     The occlusion balloon  330  may be configured to roll upon itself as the elongate shaft  312  is advanced through a blood vessel of a patient with the occlusion balloon  330  inflated, or at least partially inflated, and in contact with the inner surface of a blood vessel. 
     The stent delivery catheter  310  may include a fluid discharge port  326  at a location in the distal region of the elongate shaft  312 . For example, the fluid discharge port  326  may be located proximal of the inflation balloon  320 . However, in other embodiments, the fluid discharge port  326  may be located distal of the inflation balloon  320 . 
     The fluid discharge port  326  may be configured to discharge a fluid, such as a lubricious fluid or a therapeutic agent, out of the elongate shaft  312  and into the lumen of a blood vessel during delivery of the stent  318  to a target location of a patient&#39;s body. In some embodiments, the fluid discharge port  326  may be configured such that a fluid expelled from the fluid discharge port  326  is directed toward the stent  318  and/or inflation balloon  320 . 
     The fluid discharge port  326  may be located at a desired radial location of the elongate shaft  312 . For example, the fluid discharge port  326  may be eccentrically located to one side of the elongate shaft  312 . The opening of the fluid discharge port  326  may be in fluid communication with a fluid injection lumen of the elongate shaft  312 . The location of the fluid discharge port  326  may direct a fluid expelled from the fluid discharge port  326  in a desired radial direction such that fluid discharged from the fluid discharge port  326  is not evenly discharged in all radial directions from the elongate shaft  312 . In some embodiments directional discharge of a fluid from the fluid discharge port  326  may be desired. For example, a fluid discharged from the fluid discharge port  326  may be used as a steering mechanism to urge the elongate shaft  312  around a curve and/or away from a wall of a blood vessel. 
       FIGS. 9A and 9B  illustrate the distal region of another stent delivery catheter  410 . The stent delivery catheter  410  may include an elongate shaft  412  extending from a proximal end of the stent delivery catheter  410  to the distal end of the stent delivery catheter  410 . An inflation balloon  420  may be secured to the distal region of the elongate shaft  412 . For example, the proximal waist  422  of the inflation balloon  420  may be secured to the elongate shaft  412  and/or the distal waist  424  of the inflation balloon  420  may be secured to the elongate shaft  412 . In some embodiments, the proximal waist  422  and/or the distal waist  424  may be bonded, such as adhesively or thermally bonded, to the elongate shaft  412 . 
     A stent  418 , or other prosthetic device, may be loaded onto the inflation balloon  420 . For instance, the stent  418  may be disposed on and extend around the circumference of a central region of the inflation balloon  420 . Although illustrated as a stent  418 , any number of devices that may be introduced subcutaneously, percutaneously or surgically may be loaded onto the inflation balloon  420 . 
     The stent delivery catheter  410  may include a fluid discharge port  426  at a location in the distal region of the elongate shaft  412 . For example, the fluid discharge port  426  may be located proximal of the inflation balloon  420 . However, in other embodiments, the fluid discharge port  426  may be located distal of the inflation balloon  420 . 
     The fluid discharge port  426  may be configured to discharge a fluid, such as a lubricious fluid or a therapeutic agent, out of the elongate shaft  412  and into the lumen of a blood vessel during delivery of the stent  418  to a target location of a patient&#39;s body. In some embodiments, the fluid discharge port  426  may be configured such that a fluid expelled from the fluid discharge port  426  is directed toward the stent  418  and/or inflation balloon  420 . 
     Similar to the fluid discharge port  26 , the fluid discharge port  426  may be a conical or funnel-shaped component concentrically disposed around the elongate shaft  412 . The opening of the fluid discharge port  426  may be in fluid communication with a fluid injection lumen of the elongate shaft  412 . The conical nature of the fluid discharge port  426  may allow a fluid, such as a lubricious fluid or a therapeutic agent, to be expelled from the fluid discharge port  426  substantially around the entire circumference of the stent  418  and/or inflation balloon  420 . Thus in such an embodiment, fluid discharged from the fluid discharge port  426  may be expelled radially outward from the shaft  412  in all radial directions. 
     The stent delivery catheter  410  may also include an occlusion member, such as an occlusion balloon  430 , disposed about the elongate shaft  412  at a location proximal of the inflation balloon  420  and the fluid discharge port  426 . The occlusion member, such as the occlusion balloon  430 , may be disposed about the elongate shaft  412  such that the elongate shaft  412  may be longitudinally translatable relative to the occlusion balloon  430 . In some embodiments, the occlusion member, such as the occlusion balloon  430 , may be longitudinally translatable relative to the elongate shaft  412  a longitudinal length equivalent to or greater than the length of the stent  418 . For example, the occlusion balloon  430  may be secured to a sleeve  470  which may be slidably disposed over the elongate shaft  412 . The occlusion balloon  430  may include a proximal waist  432  secured to the sleeve  470  and a distal waist  434  secured to the sleeve  470 . 
     As shown in  FIGS. 9A and 9B , in some embodiments, the sleeve  470  may be a tubular member  472  having a proximal end  474 , a distal end  476 , and a lumen extending therethrough. The elongate shaft  412  may be slidably disposed through the lumen of the tubular member  472 . 
     Additionally, the elongate shaft  412  may include a proximal stop  464  proximal of the proximal end  474  of the tubular member  472  and/or a distal stop  466  distal of the distal end  476  of the tubular member  472 . The proximal stop  464  may prevent the tubular member  472  from sliding proximal of the proximal stop  464  and the distal stop  466  may prevent the tubular member  472  from sliding distal of the distal stop  466 . In other words, the tubular member  472  may be slidably translatable along the elongate shaft  412  between the proximal stop  464  and the distal stop  466 . 
     The tubular member  472  may include a longitudinal slot  456  extending along a length of the tubular member  472 . The longitudinal slot  456  may be aligned with an inflation port  458  of the elongate shaft  412 . Thus, an inflation fluid may be delivered through an inflation lumen of the elongate shaft  412 , through the inflation port  458  and the longitudinal slot  456 , and into the interior of the occlusion balloon  430 . The longitudinal slot  456  allows the inflation lumen of the elongate shaft  412  to be in fluid communication with the interior of the occlusion balloon  430  regardless of the position of the tubular member  472  between the proximal stop  464  and the distal stop  466 . In some embodiments, the stent delivery catheter  410  may also include radial alignment means, such as a groove, tab, or the like, maintaining radial alignment of the inflation port  458  and the longitudinal slot  456  as the elongate shaft  412  is translated through the tubular member  472 . 
       FIG. 9A  shows the stent delivery catheter  410  with the elongate shaft  412  fully translated proximally relative to the tubular member  472 . As shown in  FIG. 9A , the distal end  476  of the tubular member  472  is in contact with the distal stop  466 .  FIG. 9B  shows the stent delivery catheter  410  with the elongate shaft  412  fully translated distally relative to the tubular member  472 . As shown in  FIG. 9B , the proximal end  474  of the tubular member  472  is in contact with the proximal stop  464 . 
     During use, the stent delivery catheter  410  may be advanced through a blood vessel with the occlusion balloon  430  and the tubular member  472  positioned in their furthest distal position (i.e., with the distal end  476  of the tubular member  472  abutting the distal stop  466 ). At a desired location within the blood vessel, for example with the stent  418  and/or inflation balloon  420  positioned just proximal of an occlusion, the occlusion balloon  430  may be inflated with an inflation fluid such that the occlusion balloon  430  contacts the inner surface of the blood vessel. While the occlusion balloon  430  is inflated and in contact with the inner surface of a blood vessel, the elongate shaft  412 , inflation balloon  420  and/or the stent  418  may be advanced distally through the blood vessel without the occlusion balloon  430  being advanced distally. In other words, the elongate shaft  412  may be translated through the tubular member  472  while the occlusion balloon  430  remains inflated within a blood vessel. In some embodiments, the stent  418  and/or inflation balloon  420  may be advanced distally across an occlusion while the occlusion balloon  430  remains at least partially inflated and expanded across the lumen of the blood vessel. 
     As the elongate shaft  412  is advanced distally relative to the tubular member  472 , the inflation port  458  of the elongate shaft  412  is translated along the longitudinal slot  456  of the tubular member  472 . Thus, the interior of the occlusion balloon  430  may remain in fluid communication with the inflation lumen of the elongate shaft  412  throughout the medical procedure. 
     At the conclusion of the medical procedure, the occlusion balloon  430  may be deflated, or partially deflated prior to removing the stent delivery catheter  410  from the blood vessel. In some embodiments, this may be accomplished by drawing a vacuum through the inflation lumen of the elongate shaft  412  to draw down the occlusion balloon  430 . 
       FIGS. 10A through 10C  illustrate the distal region of another stent delivery catheter  510 . The stent delivery catheter  510  may include an elongate shaft  512  extending from a proximal end of the stent delivery catheter  510  to the distal end of the stent delivery catheter  510 . An inflation balloon  520  may be secured to the distal region of the elongate shaft  512 . For example, the proximal waist  522  of the inflation balloon  520  may be secured to the elongate shaft  512  and/or the distal waist  524  of the inflation balloon  520  may be secured to the elongate shaft  512 . In some embodiments, the proximal waist  522  and/or the distal waist  524  may be bonded, such as adhesively or thermally bonded, to the elongate shaft  512 . 
     A stent  518 , or other prosthetic device, may be loaded onto the inflation balloon  520 . For instance, the stent  518  may be disposed on and extend around the circumference of a central region of the inflation balloon  520 . Although illustrated as a stent  518 , any number of devices that may be introduced subcutaneously, percutaneously or surgically may be loaded onto the inflation balloon  520 . 
     The stent delivery catheter  510  may include a fluid discharge port  526  at a location in the distal region of the elongate shaft  512 . For example, the fluid discharge port  526  may be located proximal of the inflation balloon  520 . However, in other embodiments, the fluid discharge port  526  may be located distal of the inflation balloon  520 . 
     The fluid discharge port  526  may be configured to discharge a fluid, such as a lubricious fluid or a therapeutic agent, out of the elongate shaft  512  and into the lumen of a blood vessel during delivery of the stent  518  to a target location of a patient&#39;s body. In some embodiments, the fluid discharge port  526  may be configured such that a fluid expelled from the fluid discharge port  526  is directed toward the stent  518 . 
     Similar to the fluid discharge port  26 , the fluid discharge port  526  may be a conical or funnel-shaped component concentrically disposed around the elongate shaft  512 . The opening of the fluid discharge port  526  may be in fluid communication with a fluid injection lumen of the elongate shaft  512 . The conical nature of the fluid discharge port  526  may allow a fluid, such as a lubricious fluid or a therapeutic agent, to be expelled from the fluid discharge port  526  substantially around the entire circumference of the stent  518 . Thus in such an embodiment fluid, discharged from the fluid discharge port  526  may be expelled radially outward from the shaft  512  in all radial directions. 
     The stent delivery catheter  510  may also include an occlusion member  530  disposed about the elongate shaft  512  at a location proximal of the inflation balloon  520  and the fluid discharge port  526 . The occlusion member  530  may be disposed about the elongate shaft  512  such that the elongate shaft  512  may be longitudinally translatable relative to the occlusion member  530 . In some embodiments, the occlusion member  530  may be longitudinally translatable relative to the elongate shaft  512  a longitudinal length equivalent to or greater than the length of the stent  518 . For example, the occlusion member  530  may include a sleeve  570  which may be slidably disposed over the elongate shaft  512 . 
     As shown in  FIGS. 10A through 10C , in some embodiments, the sleeve  570  may be a tubular member  572  having a proximal end  574 , a distal end  576 , and a lumen extending therethrough. The elongate shaft  512  may be slidably disposed through the lumen of the tubular member  572 . 
     Additionally, the elongate shaft  512  may include a proximal stop  564  proximal of the proximal end  574  of the tubular member  572  and/or a distal stop  566  distal of the distal end  576  of the tubular member  572 . The proximal stop  564  may prevent the tubular member  572  from sliding proximal of the proximal stop  564  and the distal stop  566  may prevent the tubular member  572  from sliding distal of the distal stop  566 . In other words, the tubular member  572  may be slidably translatable along the elongate shaft  512  between the proximal stop  564  and the distal stop  566 . 
     The occlusion member  530  may include a framework  590 , such as an expandable framework, coupled to the tubular member  572 . The framework  590  may be movable between a collapsed state, as shown in  FIG. 10A , and an expanded state, as shown in  FIG. 10B . In the expanded state, the occlusion member  530  may extend substantially across a blood vessel lumen. 
     A membrane  592  (shown in  FIG. 10B ), such as a non-permeable membrane, may be attached to the framework  590 . Thus, when the framework  590  is expanded radially outward across a blood vessel lumen, the membrane  592  may substantially extend across the blood vessel lumen, inhibiting blood flow past the occlusion member  530 . In embodiments utilizing a non-permeable membrane  592 , the membrane  592  may generally not allow blood to flow through the membrane  592 . 
     During use, the stent delivery catheter  510  may be advanced through a blood vessel with the occlusion member  530  positioned in its furthest distal position (i.e., with the distal end  576  of the tubular member  572  abutting the distal stop  566 ). At a desired location within the blood vessel, for example with the stent  518  positioned just proximal of an occlusion, the occlusion member  530  may be expanded such that the occlusion member  530  contacts the inner surface of the blood vessel. For example, the framework  590  of the occlusion member  530  may be radially expanded, moving the non-permeable membrane  592  across the lumen of the blood vessel. 
     While the occlusion member  530  is expanded and in contact with the inner surface of a blood vessel, the elongate shaft  512 , inflation balloon  520  and/or the stent  518  may be advanced distally through the blood vessel without the occlusion member  530  being advanced distally. In other words, as shown in  FIG. 10C , the elongate shaft  512  may be translated through the tubular member  572  while the occlusion member  530  remains expanded within a blood vessel. Thus, as the elongate shaft  512  is translated distally through the tubular member  572 , the distance between the stent  518  and/or inflation balloon  520  and the occlusion member  530  may increase. In some embodiments, the stent  518  may be advanced distally across an occlusion while the occlusion member  530  remains at least partially expanded across the lumen of the blood vessel. 
     At the conclusion of the medical procedure, the occlusion member  530  may be retracted, or partially retracted prior to removing the stent delivery catheter  510  from the blood vessel. In some embodiments, this may be accomplished by actuating the framework  590  to draw down the non-permeable membrane  592  of the occlusion member  530 . For instance, a retrieval cannula may be advanced over the elongate shaft  512  of the stent delivery catheter  510  to aid in withdrawing the stent delivery catheter from a blood vessel at the conclusion of a medical procedure. 
     Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.