Patent Publication Number: US-2005137620-A1

Title: Balloon catheter retrieval device

Description:
FIELD OF THE INVENTION  
      The present invention is related to the field of medical devices. In particular, the present invention is related to the field of catheters.  
     BACKGROUND OF THE INVENTION  
      Heart and vascular disease are major problems in the United States and throughout the world. Conditions such as atherosclerosis result in blood vessels becoming blocked or narrowed. This blockage can result in lack of oxygenation of the heart, which has significant consequences, since the heart muscle must be well oxygenated in order to maintain its blood pumping action.  
      Occluded, stenotic, or narrowed blood vessels may be treated with a number of relatively non-invasive medical procedures including percutaneous transluminal angioplasty (PTA), percutaneous transluminal coronary angioplasty (PTCA), and atherectomy. Angioplasty techniques typically involve the use of a balloon catheter. The balloon catheter is advanced over a guidewire so that the balloon is positioned adjacent a stenotic lesion. The balloon is then inflated, and the restriction of the vessel is opened.  
      A wide variety of balloon catheters and angioplasty balloons exist, each with certain advantages and disadvantages. A balloon procedure can have an associated risk in that the balloon may become lodged within the patient&#39;s vasculature. If the balloon is lodged within the patient&#39;s vasculature or caught on an implanted stent, the operator must either apply additional force to the catheter, subjecting the device to a higher risk of failure or the balloon must be removed surgically, subjecting the patient to the risks of surgery. There is an ongoing need for balloon catheter retrieval devices.  
     SUMMARY OF THE INVENTION  
      Generally, the present invention relates to an intracorporeal retrieval device useful for a variety of applications including, for example, retrieval of a balloon catheter.  
      In one embodiment, an intracorporeal assembly includes an elongated shaft having a proximal portion and an opposing distal portion, a balloon disposed on the distal portion, and a tubular member disposed about the elongated shaft. The tubular member can slide from the proximal portion to the distal portion of the elongate shaft to surround a portion of the balloon.  
      In another embodiment, a method includes placing an elongate shaft having a proximal portion outside a subject vasculature and a distal portion within the subject vasculature. A balloon disposed on the distal portion is expanded within the subject vasculature. A tubular member disposed about the elongate shaft is moved from the proximal portion of the elongate shaft to the distal portion of the elongate shaft to surround a portion of the balloon. The tubular member, balloon and elongate shaft are removed from the subject vasculature.  
      The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures and Detailed Description which follow more particularly exemplify these embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:  
       FIG. 1  is a side elevation view of a balloon catheter deployed within a subject vasculature;  
       FIG. 1A  is a cross-sectional view of the catheter shaft of  FIG. 1 . taken along line  1 A- 1 A;  
       FIG. 2  is a perspective view of a balloon catheter and tubular member assembly;  
       FIG. 3  is a perspective view of a proximal end of a tubular member showing an exemplary gripping surface;  
       FIG. 4  is a top view of an exemplary eyeloop;  
       FIG. 5  is a front elevation view of the eyeloop shown in  FIG. 4 ;  
       FIG. 6  is a side elevation view of the eyeloop shown in  FIG. 4 ;  
       FIG. 7  is a side elevation view of the balloon catheter shown in  FIG. 1  lodged within a subject vasculature;  
       FIG. 8  is a side elevation view of the balloon catheter shown in  FIG. 1  being dislodged within a subject vasculature; and  
       FIG. 9  is a side elevation view of the balloon catheter shown in  FIG. 1  being removed from within a subject vasculature with the tubular 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 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 OF THE PREFERRED EMBODIMENTS  
      The intracorporeal retrieval device and method for using the intracorporeal retrieval device of the present invention are believed to be applicable to a variety of applications where retrieval of intracorporeal devices is desired, for example, retrieval of a balloon catheter from vasculature. While the present invention is not so limited, an appreciation of various aspects of the invention will be gained through a discussion of the examples provided below.  
      The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).  
      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. Thus, for example, reference to a composition containing “a compound” includes a mixture of two or more compounds. 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.  
      Also, while the tubular members illustrated in the Figures have generally circular cross sections, this is not a necessary part of the present invention, and the tubular members are merely shown as such for purposes of simplicity in illustration.  
      Angioplasty techniques have been shown to be effective for at least some intravascular interventions.  FIG. 1  illustrates an example angioplasty catheter  10  positioned in a blood vessel  12  adjacent an intravascular lesion  14 . Catheter  10  may include a balloon  16  coupled to a catheter shaft  18 . In general, catheter  10  may be advanced over a guidewire  22  through the vasculature to a target area. Balloon  16  can then be inflated to expand lesion  14 . The target area may be within any suitable peripheral or cardiac location.  
      Balloon  16  may be made from typical angioplasty balloon materials including polymers such as polyethylene terephthalate (PET), polyetherimide (PEI), polyethylene (PE), etc. Some other examples of suitable polymers, including lubricious polymers, may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM), polybutylene terephthalate (PBT), polyether block ester, polyurethane, polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, a polyether-ester elastomer such as ARNITEL® available from DSM Engineering Plastics), polyester (for example, a polyester elastomer such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example, available under the trade name PEBAX®), silicones, Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example, REXELL®), polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA), other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. In some embodiments, it may be desirable to use high modulus or generally stiffer materials so as to reduce balloon elongation. The above list of materials includes some examples of higher modulus materials. Some other examples of stiffer materials include polymers blended with liquid crystal polymer (LCP) as well as the materials listed above. For example, the mixture can contain up to about 5% LCP.  
      Shaft  18  may be a catheter shaft, similar to typical catheter shafts.  FIG. 1A  is a cross-sectional view of the catheter shaft shown in  FIG. 1 . For example, shaft  18  may include an inner tubular member  24  and outer tubular member  26 . Tubular members  24 / 26  may be manufactured from a number of different materials. For example, tubular members  24 / 26  may be made of metals, metal alloys, polymers, metal-polymer composites or any other suitable materials. Some examples of suitable metals and metal alloys include stainless steel, such as  304 V,  304 L, and  316 L stainless steel; nickel-titanium alloy such as linear-elastic or super-elastic Nitinol, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, tungsten or tungsten alloys, MP35-N (having a composition of about 35% Ni, 35% Co, 20% Cr, 9.75% Mo, a maximum 1% Fe, a maximum 1% Ti, a maximum 0.25% C, a maximum 0.15% Mn, and a maximum 0.15% Si), hastelloy, monel 400, inconel 825, or the like; or other suitable material. Some examples of suitable polymers include those described above in relation to balloon  16 . Of course, any other suitable polymer may be used without departing from the spirit of the invention. The materials used to manufacture inner tubular member  24  may be the same as or be different from the materials used to manufacture outer tubular member  26 .  
      Tubular members  24 / 26  may be arranged in any appropriate way. For example, in some embodiments, inner tubular member  24  can be disposed coaxially within outer tubular member  26 . According to these embodiments, inner and outer tubular members  24 / 26  may or may not be secured to one another along the general longitudinal axis of shaft  18 . Alternatively, inner tubular member  24  may follow the inner wall or otherwise be disposed adjacent the inner wall of outer tubular member  26 . Again, inner and outer tubular members  24 / 26  may or may not be secured to one another. For example, inner and outer tubular members  24 / 26  may be bonded, welded (including tack welding or any other welding technique), or otherwise secured at a bond point. In some embodiments, the bond point may be generally disposed near the distal end of shaft  18 . However, one or more bond points may be disposed at any position along shaft  18 . The bond may desirably impact, for example, the stability and the ability of tubular members  24 / 26  to maintain their position relative to one another. In still other embodiments, inner and outer tubular member  24 / 26  may be adjacent to and substantially parallel to one another so that they are non-overlapping. In these embodiments, shaft  18  may include an outer sheath that is disposed over tubular members  24 / 26 .  
      Inner tubular member  24  may include an inner lumen  28 . In at least some embodiments, inner lumen  28  is a guidewire lumen. Accordingly, catheter  10  can be advanced over guidewire  22  to the desired location. The guidewire lumen may extend along essentially the entire length of catheter shaft  18  so that catheter  10  resembles traditional “over-the-wire” catheters. Alternatively, the guidewire lumen may extend along only a portion of shaft  18  so that catheter  10  resembles “single-operator-exchange” or “rapid-exchange” catheters. Regardless of which type of catheter is contemplated, catheter  10  may be configured so that balloon  16  is disposed over at least a region of inner lumen  28 . In at least some of these embodiments, inner lumen  28  (i.e., the portion of inner lumen  28  that balloon  16  is disposed over) may be substantially coaxial with balloon  16 .  
      Shaft  18  may also include an inflation lumen  30  that may be used, for example, to transport inflation media to and from balloon  16 . The location and position of inflation lumen  30  may vary, depending on the configuration of tubular members  24 / 26 . For example, when outer tubular member  26  is disposed over inner tubular member  24 , inflation lumen  30  may be defined within the space between tubular members  24 / 26 . Moreover, depending on the position of inner tubular member  24  within outer tubular member  26 , the shape of lumen  30  (i.e., the shape adjacent shaft  18 ) may vary. For example, if inner tubular member  24  is attached to or disposed adjacent to the inside surface of outer tubular member  26 , then inflation lumen  30  may be generally half-moon in shape; whereas if inner tubular member  24  is generally coaxial with outer tubular member  26 , then inflation lumen  30  may be generally ring-shaped or annular in shape. It can be appreciated that if outer tubular member  26  is disposed alongside inner tubular member  24 , then lumen  30  may be the lumen of outer tubular member  26  or it may be the space defined between the outer surface of tubular members  24 / 26  and the outer sheath disposed thereover.  
      Balloon  16  may be coupled to catheter shaft  18  in any of a number of suitable ways. For example, balloon  16  may be adhesively or thermally bonded to shaft  18 . In some embodiments, a proximal waist  32  of balloon  16  may be bonded to shaft  18 , for example, at outer tubular member  26 , and a distal waist  34  may be bonded to shaft  18 , for example, at inner tubular member  24 . The exact bonding positions, however, may vary. It can be appreciated that a section of proximal waist  32  may not have sections  36  extending therefrom in order for suitable bonding between balloon  16  and outer tubular member  30 .  
      In addition to some of the structures described above, shaft  18  may also include a number of other structural elements, including those typically associated with catheter shafts. For example, shaft  18  may include a radiopaque marker coupled thereto that may aid a user in determining the location of catheter  10  within the vasculature. In addition, catheter  10  may include a folding spring (not shown) coupled to balloon  16 , for example, adjacent proximal waist  32 , which may further help in balloon folding and refolding. A description of a suitable folding spring can be found in U.S. Pat. No. 6,425,882, which is incorporated herein by reference.  
      Every angioplasty procedure has a risk that the balloon will become lodged or stuck within the subject vasculature. The balloon can get caught on a stent or artificial object that was placed within the subject or the balloon can get caught on the lesion or other vasculature architecture. In addition, during deflation the balloon may not rewrap to its original size prior to inflation. In all these cases, the balloon must be extracted by either applying additional forces to the balloon catheter and risking product failure within the subject vasculature or extracting the balloon via surgery. However, in accordance with the present invention, a tubular assembly may be used to dislodge stuck balloon catheters from the subject vasculature.  
       FIG. 2  is a perspective view of a balloon catheter  1  and tubular member  30  assembly. The tubular member  30  can be disposed about the elongate shaft  18  of the balloon catheter  1 . The tubular member  30  can slide from a proximal portion  17  of the elongate shaft  18  to a distal portion  19  of the elongate shaft  18  and surround a portion of the balloon  16 . The balloon catheter  1  may be any useful type of balloon catheter such as, for example, a cardiovascular balloon catheter or a peripheral vascular balloon catheter. The balloon catheter  1  may or may not be loaded with a stent.  
      The elongate shaft  18  is an elongate member  18  having a length L em  defined by the distance between an end of a proximal portion  17  and an opposing end of a distal portion  19 . The elongate member length L em  can be any length that allows the balloon  16  to reach the target within the subject vasculature such as, for example, 10 to 300 cm, 50 to 200 cm or 100 to 150 cm.  
      The tubular member  30  has a lumen  32  defined by a tubular member inner surface  33  having an inner diameter  37 . The tubular member lumen  32  can be any operable diameter to encompass a balloon catheter shaft. The tubular member lumen  32  or inner diameter can be any useful size such as, for example, 0.01 to 1 inch, 0.02 to 0.5 inch, or 0.02 to 0.2 inch.  
      The tubular member  30  has a length L tm  defined by the distance between a tubular member proximal end  34  and an opposing tubular member distal end  36 . The tubular member length L tm  can be any operable length to reach the balloon within the subject vasculature such as, for example, 10 to 300 cm, 50 to 200 cm or 100 to 150 cm.  
      The tubular member length L tm  can be equal to or greater than the elongate member length L em . Alternatively, the tubular member length L tm  can be equal to or less than the elongate member length L em .  
      The tubular member  30  has a wall  38  defined by the distance between the tubular member inner diameter  37  (inner surface  33 ) and the tubular member outer diameter  39  (outer surface  31 ). The wall  38  can be any operable thickness that provides enough rigidity to be able to push the tubular member  30  to the lodged balloon, but is not so thick as to hinder the tubular member  30  flexibility to follow the curvature of the subject vasculature. The tubular member wall thickness can be, for example, 0.001 to 0.1 inch, or 0.001 to 0.05 inch. In an illustrative embodiment, the tubular member  30  is large enough to slide over a conventional balloon catheter  1  but small enough to fit within a conventional guide catheter.  
      The tubular member  30  can include a radiopaque marker  40  disposed at or near the tubular member distal end  36 . The radiopaque marker  40  aids a user in determining the location of the tubular member distal end  36  within the vasculature. The radiopaque marker can be formed of any radiopaque material.  
      The tubular member  30  can be formed of a lubricious material or include a coating  50  of a lubricious material in the tubular member inner surface  33  or tubular member outer surface  31  or on both the inner surface  33  and the outer surface  31 .  
      The tubular member  30  can include a slit  60  extending through the tubular member wall  38  along a portion of the tubular member length L tm , or along the entire tubular member length L tm . The slit  60  can begin at the tubular member proximal end  34  and end short of the tubular member distal end  36 . The slit  60  can extend 50%, 60%, 70%, 80% or 90% of the total tubular member length L tm .  
      In one embodiment, the tubular member  30  can include an eyeloop  65  for engaging the balloon catheter  1 . The eyeloop  65  defines an eyeloop opening  66  extending through the eyeloop  65 . The eyeloop  65  can be any desired shape that provides for the operation of the device such as, for example, circular, elliptical, and the like. The balloon catheter  1  or elongate shaft  18  can extend through the eyeloop opening  66 . The eyeloop  65  can be slidably engaged along the tubular member slit  60 . An exemplary eyeloop  65  is further described below. The tubular member  30  can include a gripping surface  70  described below.  
      A gripping surface  70  can be disposed at or near the proximal end  34  of the tubular member  30 . The gripping surface  70  provides an enhanced user interface with the tubular member  30  by allowing the user to easily manipulate the tubular member  30  within the subject vasculature. The gripping surface  70  allows the user to easily advance the tubular member  30  forward toward the stuck balloon or to easily reverse retrieval of the balloon.  
       FIG. 3  shows an illustrative embodiment of the gripping surface  70 . In this embodiment, the gripping surface  70  can be exemplified by a pair of double-sided wings set on the tubular member outer surface  31 . The pair of double-sided wings are configured to allow human fingers to fit inside the wings cradle to control advancement and/or withdrawal of the tubular member  30  within the vasculature.  
       FIG. 4  is a top view of an exemplary eyeloop  65 .  FIG. 5  is a front elevation view of the eyeloop  65  shown in  FIG. 4 .  FIG. 6  is a side elevation view of the eyeloop  65  shown in  FIG. 4 . In the illustrative embodiment, the eyeloop  65  can include an eyeloop opening  66 , a slot  67  and wings  68 . A balloon catheter can be preloaded into the eyeloop opening  66  prior to a procedure. The slot  67  engages each side of the slit  60 , holding each side of the slit  60  in place. When the tubular member  30  is needed to retrieve a balloon, the tubular member  30  can be advanced distally forward along the balloon catheter  1  elongate shaft  18 . At the same time, the eyeloop  65  can be slide in a proximal direction engaging more of the tubular member  30  on the elongate shaft. In the illustrative embodiment, the eyeloop  65  can be moved via wings  68  placed on the eyeloop  65 . The wings  68  can be configured to allow a user to manipulate the position of the eyeloop  65  along the length of the slit  60  with the user&#39;s fingers.  
       FIG. 7  is a side elevation view of the balloon catheter  1  shown in  FIG. 1  lodged within a subject vasculature  12 .  FIG. 8  is a side elevation view of the balloon catheter  1  shown in  FIG. 1  being dislodged within a subject vasculature  12 .  FIG. 9  is a side elevation view of the balloon catheter  1  shown in  FIG. 1  being removed within a subject vasculature  12  with the tubular member  30 . As shown in  FIG. 7 , the tubular member  30  can be advanced into a vessel  12  around the balloon catheter  1  elongate shaft  18  and within for example, an introducer sheath  2  and/or guide catheter  3 . The tubular member  30  is advanced to the lodged balloon catheter  1  and surrounds a portion of the balloon  16 . The tubular member distal end  36  can touch the balloon  16  or interface between the balloon  16  and vessel  12  or stent (not shown) and cause the balloon  16  to be dislodged from the vasculature  12  or stent and rewrap to allow for easy withdrawal from the vasculature  12 .  
      During the above procedure, a proximal portion of the tubular member  30  can remain outside the vasculature  12 . In one illustrative embodiment, the tubular member  30  can be pre-loaded onto the balloon catheter  1  prior to the procedure. A preloaded tubular member  30  can have a slit  60  extending along a portion of the tubular member length L tm  as described above. The tubular member  30  can be advanced along the elongate member  18  to the stuck balloon  16 . The tubular member “swallows” the balloon  16  and allows the tubular member  30 , balloon  16 , and elongate shaft  18  to be removed at the same time from the vasculature  12 .  
      In another illustrative embodiment, the tubular member  30  can be loaded onto the balloon catheter  1  elongate member  18  prior to the procedure or after the balloon  16  is placed within the vasculature. The tubular member can have a slit  60  extending along the entire length of the tubular member  30 . The tubular member  30  can be loaded onto the elongate member  18  via the slit  60  and advanced along the elongate member  18  to the stuck balloon  16 . The tubular member  30  “swallows” the balloon  16  and allows the tubular member  30 , balloon  16 , and elongate shaft  18  to be removed at the same time from the vasculature  12 .  
      In another illustrative embodiment, the tubular member  30  without a slit  60  can be loaded onto the balloon catheter  1  elongate member  18  after the balloon  16  is placed within the vasculature by advancing the tubular member  30  along the elongate member  18  to the stuck balloon  16 . The tubular member “swallows” the balloon  16  and allows the tubular member  30 , balloon  16 , and elongate shaft  18  to be removed at the same time from the vasculature  12 .  
      The present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention can be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the instant specification.