Cryogenic balloon ablation instruments and systems

Abstract

Cryogenic tissue ablation instruments for treating body tissue include an elongate flexible body with a proximal supply port for coupling with a pressurized coolant (e.g., liquid N 2 O), a supply lumen in fluid communication with the proximal supply port, and an expandable cryogenic balloon carried on a distal portion of the elongate body, the balloon having a wall defining an interior of the balloon. A dispersion member coupled to or otherwise formed out of a distal end portion of the elongate body has an interior lumen in fluid communication with or otherwise comprising a portion of the supply lumen, the dispersion member having one or more coolant dispersion apertures in fluid communication with the balloon interior and sized and located with respect to the balloon wall such that a pressurized flowable coolant in the supply lumen will enter the balloon interior through the one or more apertures in the form of a liquid spray that contacts and provides (through rapid evaporation) substantially uniform cooling of an interior wall surface of a treatment region of the balloon.

1 . A cryogenic tissue ablation instrument, comprising:
 an elongate flexible body having a proximal supply port adapted for coupling with a source of pressurized flowable coolant, and a supply lumen in fluid communication with the proximal supply port and extending through the elongate body to a distal portion thereof;   a dispersion member coupled to or formed out of the distal portion of the elongate body, the dispersion member including an interior lumen in fluid communication with or otherwise comprising a portion of the supply lumen; and   an expandable balloon carried on the distal portion of the elongate body and having a wall, an interior surface of the wall defining an interior of the balloon, the dispersion member at least partially extending into the balloon interior and having a plurality of coolant dispersion apertures in fluid communication with the respective supply lumen and balloon interior,   wherein the coolant dispersion apertures are sized and located on the dispersion member such that a pressurized flowable coolant provided in the supply lumen will enter the balloon interior through the dispersion apertures in the form of a liquid spray that contacts and provides substantially uniform cooling of the interior wall surface of a treatment region of the balloon.   
     
     
         2 . The instrument of  claim 1 , the treatment region includes an entire circumference of the balloon. 
     
     
         3 . The instrument of  claim 1 , wherein the balloon is semi-compliant or compliant. 
     
     
         4 . The instrument of  claim 1 , wherein at least two of the coolant dispersion apertures are offset axially on the dispersion member within the balloon interior. 
     
     
         5 . The instrument of  claim 4 , the axially offset apertures including a first aperture having a first aperture size, and a second aperture located distally on the elongate member from the first aperture and having a second aperture size greater than the first aperture size. 
     
     
         6 . The instrument of  claim 1 , wherein at least two of the coolant dispersion apertures are offset circumferentially on the dispersion member within the balloon interior. 
     
     
         7 . The instrument of  claim 6 , the dispersion member comprising a first plurality of circumferentially spaced coolant dispersion apertures, and a second plurality of circumferentially spaced coolant dispersion apertures located distally on the dispersion member from the first plurality. 
     
     
         8 . The instrument of  claim 1 , wherein the coolant dispersion apertures have shapes selected from the group comprising circular, rectangular, and elliptical. 
     
     
         9 . The instrument of  claim 1 , the balloon having a collapsed delivery profile sized for passage through a working channel of an endoscopic instrument into a human esophagus, and an expanded treatment profile sized such that, when the balloon is transitioned from its collapsed delivery profile to its expanded treatment profile, an exterior wall surface of the balloon contacts and smoothes the esophageal wall tissue. 
     
     
         10 . The instrument of  claim 9 , wherein the balloon is semi-compliant or compliant. 
     
     
         11 . The instrument of  claim 1 , the balloon wall having an exterior surface comprising or coated with a lubricious material. 
     
     
         12 . The instrument of  claim 1 , the balloon wall comprising a polymer material and a non-polymer material, the non-polymer material having a greater thermal conductivity than the polymer material. 
     
     
         13 . The instrument of  claim 12 , the non-polymer material distributed in the balloon in such quantity and configuration so as to substantially increase the thermal conductivity of the balloon above the conductivity it would have in the absence of the non-polymer material. 
     
     
         14 . The instrument of  claim 12 , the non-polymer material comprising metallic strips, fibers, or particles. 
     
     
         15 . The instrument of  claim 12 , wherein the non-polymer material is attached to or embedded in the balloon wall. 
     
     
         16 . The instrument of  claim 12 , the non-polymer material comprising a plurality of circumferentially spaced metallic strips. 
     
     
         17 . The instrument of  claim 12 , the non-polymer material comprising a plurality of longitudinally spaced metallic strips. 
     
     
         18 . The instrument of  claim 1 , the balloon wall comprising a material allowing for direct visualization through the balloon wall. 
     
     
         19 . The instrument of  claim 1 , further comprising thermochromic material carried on or in the balloon wall, the thermochromic material selected so as to undergo a visual change in appearance when the balloon wall reaches a selected tissue ablation temperature. 
     
     
         20 . A system including the instrument of  claim 1 , wherein the source of pressurized flowable coolant is fluidly coupled to the proximal supply port, and further comprising a controller operatively coupled with the source of pressurized flowable coolant so as to controllably release the coolant into the supply lumen. 
     
     
         21 . The system of  claim 20 , further comprising one or more temperature sensors carried on or in the balloon wall and cooperatively coupled to the controller, wherein the controller regulates release of coolant into the supply lumen based at least in part on input from the one or more temperature sensors. 
     
     
         22 . A cryogenic tissue ablation instrument, comprising:
 an elongate flexible body having a proximal supply port adapted for coupling with a source of pressurized flowable coolant, and a supply lumen in fluid communication with the proximal supply port and extending through the elongate body to a distal portion thereof;   a dispersion member coupled to or formed out of the distal portion of the elongate body, the dispersion member including an interior lumen in fluid communication with or otherwise comprising a portion of the supply lumen; and   an expandable balloon carried on the distal portion of the elongate body, the balloon having a wall with an interior surface of the wall defining an interior of the balloon, the dispersion member at least partially extending into the balloon interior and having one or more diffusers provided therein, the one or more diffusers each configured to direct a the coolant from the supply lumen in the form of a liquid spray onto the interior balloon wall surface, wherein the one or more diffusers are sized and located on the dispersion member such that the liquid spray contacts and provides substantially uniform cooling of the interior wall surface of a treatment region of the balloon.   
     
     
         23 . The instrument of  claim 22 , the treatment region includes an entire circumference of the balloon. 
     
     
         24 . The instrument of  claim 22 , further comprising one or more deflectors carried on the dispersion member within the balloon interior, each of the one or more deflectors configured to deflect at least a portion of the liquid spray onto a respective area of the balloon wall. 
     
     
         25 . A cryogenic tissue ablation instrument, comprising:
 an elongate flexible body having a proximal supply port adapted for coupling with a source of pressurized flowable coolant, and a plurality of circumferentially spaced coolant supply lumens, each coolant supply lumen in fluid communication with the proximal supply port and extending through the elongate body to a distal portion thereof;   a dispersion member coupled to or formed out of the distal portion of the elongate body, the dispersion member including a plurality of interior lumens, each in fluid communication with or otherwise comprising a portion of a respective one of the supply lumens; and   an expandable balloon carried on the distal portion of the elongate body, the balloon having a wall with an interior surface of the wall defining an interior of the balloon, the dispersion member having a portion extending at least partially into the balloon interior and having respective pluralities of coolant dispersion apertures formed therein, each plurality of coolant dispersion apertures in fluid communication with a respective one of the coolant supply lumens, the collective dispersion apertures sized and located on the elongate body such that a pressurized flowable coolant in the respective supply lumens will enter the balloon interior in the form of a liquid spray that contacts and provides substantially uniform cooling of the interior wall surface of a treatment region of the balloon.   
     
     
         26 . The instrument of  claim 25 , the treatment region includes an entire circumference of the balloon. 
     
     
         27 . The instrument of  claim 25 , the respective pluralities of coolant dispersion apertures in the dispersion member each including a first aperture having a first aperture size, and a second aperture located distally on the dispersion member from the first aperture and having a second aperture size greater than the first aperture size. 
     
     
         28 . The instrument of  claim 25 , the coolant dispersion apertures comprising respective sets of circumferentially spaced apertures spaced axially on the dispersion member. 
     
     
         29 . The instrument of  claim 25 , the portion of the dispersion member extending into the balloon interior comprising an expandable body, the respective coolant dispersion apertures being located on an exterior facing surface of the expandable body. 
     
     
         30 . A cryogenic tissue ablation instrument, comprising:
 an elongate flexible body having a proximal supply port adapted for coupling with a source of a pressurized flowable coolant, a distal portion sized for introduction into a human esophagus, and a supply lumen in fluid communication with the proximal supply port and extending through the elongate body to the distal portion;   a dispersion member coupled to or formed out of the distal portion of the elongate body, the dispersion member including an interior lumen in fluid communication with or otherwise comprising a portion of the supply lumen; and   an expandable balloon carried on the distal portion of the elongate body, the balloon having a wall, an interior surface of the wall defining an interior of the balloon, the dispersion member having one or more coolant dispersion apertures in fluid communication with the respective fluid supply lumen and balloon interior, the balloon having a collapsed delivery profile sized for passage through a working channel of an endoscopic instrument into a human esophagus, and an expanded profile sized such that, as the balloon is transitioned from its delivery profile to its expanded profile, the balloon wall contacts and smoothes the esophageal wall tissue.   
     
     
         31 . The instrument of  claim 30 , wherein in its collapsed delivery configuration the balloon wall is gathered in longitudinally oriented folds. 
     
     
         32 . The instrument of  claim 30 , wherein an exterior surface of the balloon wall comprises or is coated with a lubricious material. 
     
     
         33 . A cryogenic tissue ablation instrument, comprising:
 an elongate flexible body having a proximal supply port adapted for coupling with a source of a pressurized flowable coolant and a supply lumen in fluid communication with the proximal supply port and extending through the elongate body to a distal portion thereof;   a dispersion member coupled to or formed out of the distal portion of the elongate body, the dispersion member including an interior lumen in fluid communication with or otherwise comprising a portion of the supply lumen; and   an expandable balloon carried on the distal portion of the elongate body, the balloon having a wall, an interior surface of the wall defining an interior of the balloon, the dispersion member having one or more coolant dispersion apertures in fluid communication with the respective supply lumen and balloon interior, the one or more dispersion apertures being sized and located in the dispersion member with respect to the balloon wall such that a pressurized flowable coolant in the supply lumen will enter the balloon interior through the one or more apertures in the form of a liquid spray that contacts and provides substantially uniform cooling of an energy delivery portion of the balloon wall.   
     
     
         34 . The instrument of  claim 33 , the balloon wall comprising an insulated portion. 
     
     
         35 . The instrument of  claim 33 , the energy delivery portion of the balloon wall comprising a distal facing portion of the balloon wall, the one or more coolant dispersion apertures positioned relative to the balloon such that a pressurized flowable coolant in the supply lumen is directed axially in the form of a liquid spray applied against the interior surface of the respective distal facing wall portion of the balloon. 
     
     
         36 . The instrument of  claim 33 , the energy delivery portion of the balloon wall comprising a side facing portion of the balloon wall, the one or more coolant dispersion apertures positioned relative to the balloon such that a pressurized flowable coolant in the supply lumen is directed radially in the form of a liquid spray applied against the interior surface of the respective side facing wall portion of the balloon. 
     
     
         37 . A cryogenic tissue ablation instrument, comprising:
 an elongate flexible body having a distal portion sized for introduction into a human esophagus, and a plurality of supply lumens in fluid communication with one or more respective proximal coolant supply ports and extending through the elongate body to the distal portion;   a dispersion member coupled to or formed out of the distal portion of the elongate body, the dispersion member including a plurality of interior lumens, each in fluid communication with or otherwise comprising a portion of a respective one of the supply lumens; and   an expandable multi-lobe balloon carried on the distal portion of the elongate body and having a plurality of isolated balloon chambers, a portion of the dispersion member extending through a central region of the balloon, each of the coolant supply lumens being in fluid communication with a respective one of the isolated balloon chambers via a respective plurality of coolant dispersion apertures in the dispersion member,   the respective dispersion apertures being sized and positioned on the elongate body such that a pressurized flowable coolant in one of the supply lumens will enter the respective isolated balloon chamber through the respective dispersion apertures in the form of a liquid spray that contacts and cools of an interior wall surface of the respective balloon chamber.   
     
     
         38 . A system including the instrument of  claim 37 , wherein the source of pressurized flowable coolant is fluidly coupled to the respective one or more coolant supply ports of the instrument, and further comprising a controller operatively coupled with the source of pressurized flowable coolant so as to controllable release the coolant into a respective one or more of the supply lumens. 
     
     
         39 . A method of ablating body wall tissue using a cryogenic balloon instrument, the instrument comprising an elongate flexible member carrying an expandable balloon on a distal end thereof, the balloon having a collapsed delivery shape and an expanded treatment shape, the method comprising:
 delivering the balloon in its delivery shape through a working channel of an endoscopic instrument to a location of the wall tissue to be treated;   expanding the balloon so that an outer surface of the balloon contacts and smoothes the wall tissue to be treated; and   delivering a pressurized flowable coolant from a source external to the patient through a supply lumen in the elongate body and out one or more coolant dispersion apertures in fluid communication with the balloon interior, the one or more coolant dispersion apertures being sized and located relative to an interior wall of the balloon such that the pressurized flowable coolant enters the balloon interior in the form of a liquid spray that contacts and provides substantially uniform cooling of the interior balloon wall surface of a treatment region of the balloon.   
     
     
         40 . The method of  claim 39 , wherein gas formed as a result of evaporation of the coolant within the balloon interior is purged through an exhaust channel in the flexible member in fluid communication with the balloon interior and with a relief valve located at a proximal end thereof.