Low thermal resistance elastic sleeves for medical device balloons

Abstract

Medical devices that are configured for insertion into a body lumen, such as the male urethra, are provided with one or more inflatable balloons having elastic sleeves, wherein each elastic sleeve is adapted to inflate in response to inflation of a respective balloon, and to deflate in response to deflation of the respective balloon. When a balloon is in a deflated condition a respective elastic sleeve exerts a circumferentially compressive force against the balloon to cause a smooth, reduced cross-sectional profile of the balloon along an axial extent thereof. This smooth, reduced cross-sectional profile can facilitate passage of the medical device through a body lumen during both insertion and extraction of the medical device. A thin layer of fluid may be disposed between a treatment balloon and a respective elastic sleeve to facilitate heat transfer from a treatment balloon to a surrounding elastic sleeve or to administer a therapeutic agent to localized tissue.

That which is claimed is:  
     
         1 . A catheter configured for insertion into a body lumen, comprising: 
 a flexible elongated tubular body having an outer wall with an external surface, and at least one fluid lumen extending through the tubular body from a proximal end of the tubular body to a distal end of the tubular body;    an inflatable treatment balloon peripherally mounted to the tubular body distal end and in fluid communication with the at least one fluid lumen, wherein the treatment balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration; and    an elastic sleeve that surrounds the treatment balloon, wherein the elastic sleeve is secured to the tubular body and is adapted to inflate in response to inflation of the treatment balloon, and to deflate in response to deflation of the treatment balloon and so as to exert a circumferentially compressive force against the treatment balloon radially inward toward the outer wall external surface to cause a reduced cross-sectional profile of the treatment balloon along the axial extent of the treatment balloon, wherein the reduced cross-sectional profile of the treatment balloon facilitates passage of the catheter through a body lumen;    wherein the catheter is configured to circulate heated liquid through the at least one fluid lumen to the treatment balloon, and wherein the elastic sleeve has a low thermal resistance such that a temperature drop through the elastic sleeve is no greater than between about 0.5 degrees and about 1.5 degrees (0.5°-1.5°) when measured ex vivo.    
     
     
         2 . The catheter according to  claim 1 , further comprising an anchoring balloon peripherally mounted to the tubular body distal end at a location more distal than the treatment balloon, wherein the anchoring balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration, and wherein said elastic sleeve is configured to extend over both said treatment balloon and said anchoring balloon.  
     
     
         3 . The catheter according to  claim 1 , further comprising a material disposed between the treatment balloon and the elastic sleeve, wherein the material facilitates heat transfer from the treatment balloon to the elastic sleeve.  
     
     
         4 . The catheter according to  claim 3 , wherein the material comprises a gelatinous material at ambient temperatures.  
     
     
         5 . The catheter according to  claim 3 , wherein the material is viscous or semi-viscous at ambient temperatures.  
     
     
         6 . The catheter according to  claim 3 , wherein the material comprises a cream.  
     
     
         7 . The catheter according to  claim 6 , wherein the cream comprises a steroid.  
     
     
         8 . The catheter according to  claim 4 , wherein the gelatinous fluid comprises at least one of petroleum jelly or other biocompatible lubricant.  
     
     
         9 . The catheter according to  claim 3 , wherein, during operation the outer surface temperature of the sleeve with the material held therein is greater than the outer surface temperature of the inflatable treatment balloon without the sleeve and material when measured ex vivo.  
     
     
         10 . The catheter according to  claim 3 , wherein during operation, there is no temperature drop through the elastic sleeve and material as measured ex vivo from the temperature at the outer surface of the treatment balloon without a sleeve overlying the treatment balloon.  
     
     
         11 . The catheter according to  claim 3 , wherein the elastic sleeve has a thickness of about 0.020 inches.  
     
     
         12 . The catheter according to  claim 3 , wherein the temperature drop measured at the outer surface of the elastic sleeve is no greater than about 0.5 degrees compared to the temperature at the outer surface of the treatment balloon configured without the sleeve when measured ex vivo.  
     
     
         13 . The catheter according to  claim 4 , wherein the material further comprises a quantity of ceramic microspheres.  
     
     
         14 . The catheter according to  claim 1 , wherein the elastic sleeve comprises an elastomeric material having a Shore A durometer range of between about 20 and about 60, and wherein the elastic sleeve has a thickness between about 0.005-0.030 inches.  
     
     
         15 . The catheter according to  claim 1 , wherein the elastic sleeve comprises material selected from the group consisting of silicone, natural rubber, an in situ biodegradable material, synthetic rubber, and plasticized polyvinylchloride.  
     
     
         16 . The catheter according to  claim 3 , wherein the material is viscous, and wherein the elastic sleeve and viscous material have a combined thermal resistance such that a temperature drop through the fluid and elastic sleeve is no greater than between about 1.5 degrees and about 2.0 degrees (1.5°-2.0°) compared to a corresponding sleeveless catheter configuration when measured ex vivo during operation which circulates liquid heated to above about 40 degrees Celsius.  
     
     
         17 . A catheter configured for insertion into a body lumen, comprising: 
 a flexible elongated tubular body having an outer wall with an external surface, and at least one fluid lumen extending through the tubular body from a proximal end of the tubular body to a distal end of the tubular body;    an inflatable treatment balloon peripherally mounted to the tubular body distal end and in fluid communication with the at least one fluid lumen, wherein the treatment balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration;    an anchoring balloon peripherally mounted to the tubular body distal end at a location more distal than the treatment balloon, wherein the anchoring balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration; and    at least one elastic sleeve which axially extends to overlie and surround the anchoring and treatment balloons, wherein the elastic sleeve is secured to the tubular body and is configured to locally expand in response to inflation of each of the underlying anchoring and treatment balloons, and to deflate in response to deflation of the corresponding anchoring and treatment balloons and so as to exert a circumferentially compressive force against the anchoring and treatment balloons radially inward toward the outer wall external surface to cause a reduced cross-sectional profile of the anchoring and treatment balloons along an axial extent of the anchoring and treatment balloons, wherein the reduced cross-sectional profile of the anchoring and treatment balloon facilitates passage of the catheter through a body lumen.    
     
     
         18 . The catheter according to  claim 17 , wherein the at least one elastic sleeve is a contiguous unitary body which axially extends from a position above the anchoring balloon to a position below the treatment balloon about the tubular body.  
     
     
         19 . The catheter according to  claim 17 , wherein the at least one elastic sleeve is defined by two discrete spatially separate elastic segments.  
     
     
         20 . The catheter according to  claim 17 , further comprising a material disposed between the treatment balloon and the elastic sleeve, wherein the material facilitates heat transfer from the treatment balloon to the portion of the elastic sleeve proximate the treatment balloon.  
     
     
         21 . The catheter according to  claim 20 , wherein the material is formulated as a viscous or semi-viscous fluid at ambient temperature.  
     
     
         22 . The catheter according to  claim 21 , wherein the material is formulated to be substantially gelatinous.  
     
     
         23 . The catheter according to  claim 21 , wherein the material is formulated as a cream.  
     
     
         24 . The catheter according to  claim 20 , wherein the material has a first physical state and second different physical state different from the first physical state after exposure to thermal treatment temperatures.  
     
     
         25 . The catheter according to  claim 20 , wherein the material further comprises a quantity of particulate matter.  
     
     
         26 . The catheter according to  claim 17 , wherein the at least one elastic sleeve comprises an elastomeric material having a Shore A durometer range of between about 20 and about 60, and wherein the sleeve has a thickness of between about 0.005-0.030 inches.  
     
     
         27 . The catheter according to  claim 19 , wherein the elastic sleeve segments comprise at least one of silicone, natural rubber, synthetic rubber, an in situ biodegradable material, and plasticized polyvinylchloride materials.  
     
     
         28 . The catheter according to  claim 17 , wherein the catheter is configured to circulate liquid heated to above about 40 degrees Celsius through the at least one fluid lumen to the treatment balloon, and wherein the first elastic sleeve has a low thermal first elastic sleeve is no greater than between about 0.5 degrees and about 1.5 degrees (0.5°-1.5°) when measured during operation ex vivo as compared to a correspondingly configured sleeveless catheter.  
     
     
         29 . The catheter according to  claim 20 , wherein the catheter is configured to circulate liquid heated to above about 50 degrees Celsius through the at least one fluid lumen to the treatment balloon, and wherein the material and elastic sleeve has a combined low thermal resistance such that a temperature drop through the fluid and the elastic sleeve proximate the treatment balloon is no greater than one degree when measured ex vivo during operation compared to a correspondingly configured sleeveless catheter.  
     
     
         30 . A stent configured for insertion into a body lumen, comprising: 
 a unitary tubular body having an outer wall with an external surface;    a first balloon peripherally mounted to the tubular body, wherein the first balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration;    a second balloon peripherally mounted to the tubular body, wherein the second balloon is configured to inflate radially outward from the outer wall external surface a lesser distance than said first balloon, and to deflate to a collapsed configuration; and    an elastic sleeve that surrounds said first and second balloons, wherein the elastic sleeve is secured to the tubular body and is adapted to expand locally in response to inflation of the respective deflation of the respective underlying balloon and so as to exert a circumferentially compressive force against the first and second balloons radial inward toward the outer wall external surface to cause a reduced cross-sectional profile of the first and second balloons along an axial extent of the balloons, wherein the reduced cross-sectional profile of the balloons facilitates passage of the stent through a body lumen.    
     
     
         31 . The stent according to  claim 30 , wherein the first balloon is a treatment or tissue molding balloon, and wherein the stent further comprises a material disposed between the treatment balloon and the elastic sleeve.  
     
     
         32 . The stent according to  claim 31 , wherein the material is a viscous or semi-viscous fluid at ambient temperature.  
     
     
         33 . The stent according to  claim 31 , wherein the material is gelatinous at ambient temperature.  
     
     
         34 . The stent according to  claim 31 , wherein the material is a cream at ambient temperature.  
     
     
         35 . The stent according to  claim 31 , wherein the material comprises at least one of a medicament, an anesthetic, and a lubricant.  
     
     
         36 . The stent according to  claim 31 , wherein the material comprises a medicament for therapeutically treating urinary tract problems or enhancing the healing of damage in the urinary tract.  
     
     
         37 . The stent according to  claim 30 , wherein the elastic sleeve is configured to circumferentially compress the balloons radially inward against the outer wall external surface when the balloons are deflated.  
     
     
         38 . The Stent according to  claim 30 , wherein the elastic sleeve comprises an elastomeric material having a Shore A durometer range of between about 20 and about 60, and wherein the elastic sleeve has a thickness between about 0.005-0.030 inches.  
     
     
         39 . The stent according to  claim 30 , wherein the elastic sleeve material comprises at least one of silicone, natural rubber, synthetic rubber, an in situ biodegradable material, and plasticized polyvinylchloride.  
     
     
         40 . The stent according to  claim 30 , further comprising a third balloon peripherally mounted to the tubular body, wherein the third balloon is configured to inflate radially outward from the outer wall external surface a greater distance than said first and second balloons, and to deflate to a collapsed configuration, and wherein said elastic sleeve is configured as a unitary contiguous body to overlie all of said first, second and third balloons.  
     
     
         41 . A urinary prostatic stent configured for insertion into a body lumen, comprising: 
 a unitary tubular body having an outer wall with an external surface and having a length such that in position in the body the tubular body resides above the sphincter and in the prostatic and membraneous urethra;    a first bladder anchoring balloon peripherally mounted to the tubular body, wherein the bladder anchoring balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration;    a second tissue molding or treatment balloon peripherally mounted to the tubular body, wherein the tissue molding or treatment balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration; and    a third localized tissue anchoring balloon adapted to engage with tissue in the membraneous urethra; and    at least one elastic sleeve which is configured to axially extend and overlie and encase the three balloons, wherein the at least one elastic sleeve is secured to the tubular body and is adapted to differentially locally expand in response to inflation of one of the underlying balloons, and to deflate in response to deflation of the balloons and so as to exert a circumferentially compressive force against the three balloons radially inward toward the outer wall external surface to cause a reduced cross-sectional profile along an axial extent of the balloons that facilitates passage of the stent through a body lumen.    
     
     
         42 . The urinary stent according to  claim 41 , wherein the at least one sleeve is a single unitary body.  
     
     
         43 . The urinary stent according to  claim 41 , wherein the elastic sleeve is three separate sleeves, each configured to circumferentially compress at least one selected balloon radially inward against the outer wall external surface in response to deflation of the at least one selected balloon.  
     
     
         44 . The urinary stent according to  claim 43 , wherein the second elastic sleeve is configured to circumferentially compress the anchoring balloon radially inward against the outer wall external surface in response to deflation of the anchoring balloon, and wherein the other sleeves are configured to circumferentially compress a respective one of the tissue molding or treatment balloon and localized tissue anchoring balloons radially inward against the outer wall external surface in response to deflation of same.  
     
     
         45 . The urinary stent according to  claim 41 , wherein the at least one elastic sleeve comprises an elastomeric material having a Shore A durometer range of between about 20 and about 60.  
     
     
         46 . The urinary stent according to  claim 43 , wherein the first and second elastic sleeves comprise an elastomeric material having a Shore A durometer range of between about 20 and about 60.  
     
     
         47 . The urinary stent according to  claim 46 , wherein the three elashic sleeves comprise at least one of silicone, natural rubber, synthetic rubber, an in situ biodegradable material and plasticized polyvinylchloride materials.  
     
     
         48 . The urinary stent according to  claim 45 , wherein the elastic sleeve has a thickness between about 0.005-0.030 inches.  
     
     
         49 . A medical device configured for insertion into a body lumen, comprising: 
 an elongated tubular body having an outer wall with an external surface;    a first balloon peripherally mounted to a distal end portion of the tubular body, wherein the first balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration;    a second balloon peripherally mounted to the distal end portion of the tubular body at a location more distal than the first balloon, wherein the second balloon is configured to inflate radially outward from the outer wall external surface a greater distance than said first balloon and to deflate to a collapsed configuration; and    at least one elastic sleeve that surrounds the first and second balloons, wherein the elastic sleeve is secured to the tubular body and is adapted to locally inflate in response to inflation of one of the underlying first and second balloons, and to deflate in response to deflation of the first and second balloons and so as to exert a circumferentially compressive force against each respective balloon radially inward toward the outer wall external surface to cause a reduced cross-sectional profile of each respective balloon along the axial extent of each respective balloon, wherein the reduced cross-sectional profile of each respective balloon facilitates passage of the medical device through a body lumen.    
     
     
         50 . The medical device according to  claim 49 , wherein the medical device is configured to circulate heated liquid through at least one of the first and second balloons, and wherein the elastic sleeve has a thermal resistance such that a temperature drop through the elastic sleeve is no greater than between about 0.5 degrees and about 1.5 degrees (0.5°-1.5°) during operation when measured ex vivo as compared to a correspondingly configured sleeveless version of the medical device.  
     
     
         51 . The medical device according to  claim 49 , further comprising a viscous or semi-viscous material disposed between at least one of the first and second balloons and the elastic sleeve, wherein the material facilitates heat transfer from at least one of the first and second balloons to the elastic sleeve.  
     
     
         52 . The medical device according to  claim 51 , wherein the material and elastic sleeve have a combined low thermal resistance such that a temperature drop through the material and elastic sleeve is no greater than about one degree as measured ex vivo at the external surface of the sleeve during operation of the medical device as compared to a correspondingly configured sleeveless version of the medical device.  
     
     
         53 . The medical device according to  claim 50 , wherein the temperature drop is less than about 0.5 degrees for a treatment temperature of at least about 50 degrees Celsius.  
     
     
         54 . The medical device according to  claim 51 , wherein there is no temperature drop through the sleeve and material as measured ex vivo at the external surface of the sleeve during operation of the medical device as compared to a correspondingly configured sleeveless version of the medical device.  
     
     
         55 . The medical device according to  claim 51 , wherein there is a temperature increase at the external surface of the sleeve as measured ex vivo during operation of the medical device compared to a correspondingly configured sleeveless version.  
     
     
         56 . The medical device according to  claim 51 , wherein the material is gelatinous at ambient temperature.  
     
     
         57 . The medical device according to  claim 51 , wherein the material is a cream at ambient temperature.  
     
     
         58 . The medical device according to  claim 51 , wherein the material has a first physical state and second different physical state different from the first state after exposure to thermal treatment temperatures.  
     
     
         59 . The medical device according to  claim 49 , wherein the elastic sleeve comprises an elastomeric material having a Shore A durometer range of between about 20 and about 60, and wherein the sleeve has a thickness between about 0.005-0.030 inches.  
     
     
         60 . The medical device according to  claim 49 , wherein the elastic sleeve material comprises at least one of silicone, natural rubber, synthetic rubber, an in situ biodegradable material and plasticized polyvinylchloride.  
     
     
         61 . A method for thermally treating a natural body lumen or cavity, comprising: 
 circulating fluid heated to above about 40° C. in a closed loop system that includes a catheter with a radially expandable treatment balloon and an overlying sleeve with a quantity of a selected material disposed therebetween;    concurrently expanding the treatment balloon and sleeve;    liquefying the selected material responsive to heat delivered from the heated fluid; and    directing heat to travel through the treatment balloon, liquefied material, and sleeve, responsive to the circulating and expanding steps so that, measured ex vivo, the temperature at the outer surface of the sleeve is no greater than one degree less than the temperature at the outer surface of the treatment balloon on a corresponding sleeveless version of the catheter.    
     
     
         62 . A method according to  claim 61 , wherein the material includes a pharmaceutical substance.  
     
     
         63 . A method according to  claim 61 , wherein the material comprises petroleum jelly.  
     
     
         64 . A method according to  claim 61 , wherein, measured ex vivo, the temperature at the outer surface of the sleeve is greater than the temperature at the outer surface of the treatment balloon on a corresponding sleeveless version of the catheter.  
     
     
         65 . A method according to  claim 61 , wherein the liquid is heated to above 45° C.  
     
     
         66 . A catheter configured for insertion into a body lumen or cavity to deliver thermal treatment to a subject, comprising: 
 a flexible elongated tubular body having an outer wall with an external surface, and at least one fluid lumen extending through the tubular body from a proximal end of the tubular body to a distal end of the tubular body;    an inflatable treatment balloon peripherally mounted to the tubular body distal end and in fluid communication with the at least one fluid lumen, wherein the first balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration;    an inflatable anchoring balloon peripherally mounted to the tubular body distal end at a location more distal than the treatment balloon, wherein the anchoring balloon is configured to inflate radially outward from the outer wall external surface and to deflate to a collapsed configuration;    at least one elastic sleeve which axially extends to overlie and surround the anchoring and treatment balloons, wherein the elastic sleeve is secured to the tubular body and is configured to locally expand in response to inflation of each of the underlying anchoring and treatment balloons, and to deflate in response to deflation of the corresponding anchoring and treatment balloons and so as to exert a circumferentially compressive force against the anchoring and treatment balloons radially inward toward the outer wall external surface to cause a reduced cross-sectional profile of the anchoring and treatment balloons along an axial extent of the anchoring and treatment balloons, wherein the reduced cross-sectional profile of the anchoring and treatment balloon facilitates passage of the catheter through a body lumen; and    a quantity of a viscous or semi-viscous therapeutic material at ambient temperature disposed between the sleeve and the treatment balloon.    
     
     
         67 . The catheter according to  claim 66 , wherein the elastic sleeve comprises an elastomeric material having a Shore A durometer range of between about 20 to about 60, and wherein the elastic sleeve has a thickness between about 0.005-0.030 inches.  
     
     
         68 . The catheter according to  claim 66 , wherein the at least one elastic sleeve is a contiguous unitary body which axially extends from a position above the anchoring balloon to a position below the treatment balloon about the tubular body.  
     
     
         69 . The catheter according to  claim 66 , wherein the tubular body is constructed and arranged for insertion into the male urethra so that, after insertion, the treatment balloon is in a position to perform a thermal ablation therapy on a prostate of the subject.