Patent Publication Number: US-2023135845-A1

Title: Percutaneous coiled catheter design for gallbladder cryoablation

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     n/a. 
     FIELD 
     The present technology is generally related to a device, system, and methods thereof, for ablation of the gallbladder based on an access method routinely used for drainage of the gallbladder. 
     BACKGROUND 
     Gall stone formation is a common cause of morbidity, affecting an estimated twenty million adults in the United States. Biliary colic develops in 1 to 4% of this population annually, with 20% of this group eventually developing inflammation of the gallbladder (cholecystitis). Surgical removal of the gallbladder, otherwise known as cholecystectomy, is the preferred treatment for biliary colic and cholecystitis, with more than 200,000 procedures performed annually. However, it has been postulated that ablation of the gallbladder may effectively treat these patients with less risk. 
     SUMMARY 
     The techniques of this disclosure generally relate to a device, system, and methods thereof, for ablation of the gallbladder based on an access method routinely used for drainage of the gallbladder. 
     In one embodiment, a medical system for ablating tissue within a gallbladder having a gallbladder wall includes a medical device. The medical device includes a shaft having a proximal portion and a distal portion opposite the proximal portion, and an inflatable treatment element coupled to the distal portion of the shaft and transitionable between a first deflated free-form configuration and a second inflated coiled configuration. 
     In another aspect of this embodiment, the medical device further includes a fluid supply lumen disposed within the shaft and extending within the inflatable treatment element. The fluid supply lumen defines a port. 
     In another aspect of this embodiment, the fluid supply lumen is made of a flexible material configured to readily contour and match the shape of the inflatable treatment element when the inflatable treatment element is transitioned between the first deflated free-form configuration and the second inflated configuration. 
     In another aspect of this embodiment, the port is defined along a length of the fluid supply lumen within the inflatable treatment element. 
     In another aspect of this embodiment, an electrode is disposed along an outer surface of the inflatable treatment element. 
     In another aspect of this embodiment, the electrode is configured to measure and record at least one impedance measurement signal. 
     In another aspect of this embodiment, the medical device is in communication with a console. The electrode is configured to transmit the at least one impedance measurement signal to the console. 
     In another aspect of this embodiment, the console is configured to determine a degree of tissue contact between the inflatable treatment element and the gallbladder wall based, in part, on the at least one impedance measurement signal. 
     In yet another embodiment, a medical device includes a plurality of shafts each having a proximal portion and a distal portion opposite the proximal portion, and an inflatable treatment element coupled to the distal portion of each shaft and transitionable between a first deflated free-form configuration and a second inflated coiled configuration. 
     In another aspect of this embodiment, the medical device further defines a major longitudinal axis, each inflatable treatment element is spaced apart from an adjacent inflatable treatment element along the major longitudinal axis when in the second inflated coiled configuration. 
     In another aspect of this embodiment, the medical device further includes a fluid supply lumen disposed within each shaft and extending within the inflatable treatment element coupled to each respective shaft. Each fluid supply lumen defines a port. 
     In another aspect of this embodiment, each fluid supply lumen is composed of a flexible material configured to readily contour and match the shape of each inflatable treatment element when transitioned between the first deflated free-form configuration and the second inflated configuration. 
     In another aspect of this embodiment, each inflatable treatment element is in fluid communication with a console. 
     In another aspect of this embodiment, each inflatable treatment element includes an electrode configured to measure and record at least one impedance measurement signal. 
     In another aspect of this embodiment, the electrode is configured to transmit the at least one impedance measurement signal to the console; and the console is configured to determine a degree of tissue contact between each inflatable treatment element and the gallbladder wall based, in part, on the at least one impedance measurement signal. 
     In yet another embodiment, a method of ablating an area of target tissue within a gallbladder having a gallbladder wall includes: positioning a medical device having an inflatable treatment element proximate to the area of target tissue, the inflatable treatment element transitionable between a first deflated free-form configuration and a second inflated configuration; and circulating refrigerant within the inflatable treatment element such that the inflatable treatment element transitions to the second inflated configuration and is at least in partial contact with an inner surface of the gallbladder wall. 
     In another aspect of this embodiment, the method further includes recording at least one impedance measurement signal, the at least one impedance measurement signal being recorded by an electrode; transmitting the at least one impedance measurement signal to a console; and determining a degree of tissue contact between the inflatable treatment element and the inner surface of the gallbladder wall based, in part, on the at least one impedance measurement signal. 
     In another aspect of this embodiment, the inflatable treatment element has an inner surface and an outer surface opposite the inner surface. 
     In another aspect of this embodiment, the inflatable treatment element further includes a fluid supply lumen disposed therein. The fluid supply lumen has a plurality of injection ports. 
     In another aspect of this embodiment, the refrigerant is delivered through plurality of injection ports towards the inner surface of the inflatable treatment element during the ablation phase. 
     In another aspect of this embodiment, the medical device further defines a major longitudinal axis and includes a plurality of inflatable treatment elements. Each inflatable treatment elements being spaced apart from an adjacent inflatable treatment element along the major longitudinal axis when in the second inflated coiled configuration. 
     The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG.  1    shows a first configuration of a medical system constructed in accordance with the principles of the present application; 
         FIG.  2 A  shows an inflatable treatment element of the system of  FIG.  1    in a deflated state; 
         FIG.  2 B  shows the inflatable treatment element of  FIG.  2    in an inflated state; 
         FIG.  3    shows a second configuration of the medical system constructed in accordance with the principles of the present application; 
         FIGS.  4 A and  4 B  show the process of navigating the medical device of  FIGS.  1 - 3    through a guide sheath, and inflating the inflatable treatment elements of the medical device of  FIGS.  1 - 3   ; and 
         FIG.  5    is a flowchart illustrating an example method of using the medical system of  FIG.  1 - 4 B . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawing figures where like elements have like reference numerals,  FIG.  1    illustrates a medical system for ablating tissue within a gallbladder having a gallbladder wall and designated generally as “10”. The medical system  10  may include a medical device  12  in electrical and/or fluid communication with a console  14 . As shown in  FIG.  1   , the device  12  may have a shaft  16  that includes proximal portion  18  and a distal portion  20  opposite the proximal portion  18 . Although not shown, it is to be understood that in some embodiments, the device  12  may be used together with a second medical device such as a guiding sheath  58  (discussed in more detail below) to assist in positioning the medical device  12  within a gallbladder. The shaft  16  of the medical device  12  is sized and configured to be passable through a patient’s vasculature or abdomen, and/or positionable proximate to an area of target tissue within the gallbladder. The shaft  16  provides mechanical, electrical, and/or fluid communication between the inflatable treatment element  24  and a handle  25  of the device  12 . The shaft  16  may be rigid and/or flexible to facilitate the navigation of the device  12  within the patient’s body. Additionally, the device  12  further includes an inflatable treatment element  24 . As shown in  FIG.  1   , the inflatable treatment element  24  is coupled to, and/or contiguous with, the distal end  27  of the shaft  16  so that the inflatable treatment element  24  may be passed through the patient’s vasculature towards an area of target tissue within the gallbladder. The inflatable treatment element  24  is also flexible to allow for more desirable positioning proximate to an area of target tissue within the gallbladder or gallbladder wall. The inflatable treatment element  24  may be a tube or sleeve made of memory shape material that is pre-shaped to match the contour of an inner surface of the gallbladder wall. In some configurations, the inflatable treatment element  24  may be a nitinol or polyimide injection tube covered with a thin polymer balloon sleeve. 
     Continuing to refer to  FIG.  1   , the medical device  12  is in electrical and/or fluid communication with the console  14 . The console  14  includes one or more controllers, processors, and/or software modules containing instructions or algorithms to provide for the automated operation and performance of the features, sequences, or procedures described herein. In one embodiment, for example, the console  14  includes processing circuitry  34  programmed or programmable to execute the automated or semi-automated operation and performance of the features, sequences, calculations, or procedures described herein. The processing circuitry  34   may include a memory and a processor. The memory is in electrical communication with the processor and includes instructions that, when executed by the processor, configure the processor to receive, process, or otherwise use signals from the device  12  and/or other system components. Still further, the console  14  may include one or more user input devices, controllers, speakers, and/or displays  36  for collection and conveying information from and to the user. 
     As shown in  FIG.  1   , the console  14  further includes a fluid supply reservoir  38  containing a cryogenic fluid, saline, coolant, refrigerant, or the like. The device  12  includes a flexible fluid supply lumen  40  extending through a lumen defined by the shaft  16  and within the inflatable treatment element  24 . The fluid supply lumen  40  is in fluid communication with the fluid supply reservoir  38  and/or console  14 . The processing circuitry  34  is configured and/or programmed to initiate a delivery of fluid such as air, saline, argon gas, refrigerant, or coolant, from the fluid supply reservoir  38  to the device  12  so that the inflatable treatment element  24  may be inflated or expanded. 
     Now referring to  FIGS.  2 A- 2 B , the inflatable treatment element  24  includes the flexible fluid supply lumen  40  disposed therein. The fluid supply lumen  40  may define a plurality of injection orifices, or ports  42  to facilitate the dispersion of fluid towards an inner surface of the inflatable treatment element  24 . In some configurations, as shown in  FIG.  2 A , the inflatable treatment element  24  is in a first deflated free-form state or configuration. When in the first deflated-free form configuration, the inflatable treatment element  24  may be more easily navigated within and through the patient’s body and positioned within the gallbladder. When positioned within the gallbladder, the free-form configuration allows the inflatable treatment element  24  to be more freely maneuvered around any foreign and/or undesired objects such as, for example, gallstones present within the patient’s gallbladder. Accordingly, the flexible fluid supply lumen  40  that is disposed within the inflatable treatment element  24  is also configured to readily contour and match the curvature, shape, or configuration of the inflatable treatment element  24 . As fluid is dispersed towards the inner surface  44  of the inflatable treatment element  24 , the dispersed fluid aggregates in a gaseous state within an inner chamber  46  defined between the fluid supply lumen  40  and the inner surface  44  of the inflatable treatment element  24 . As more fluid is collected within the inner chamber  46 , the inflatable treatment element  24  expands such that the diameter of the inflatable treatment element  24  is increased (as shown in  FIG.  2 B ). In other words, the inflatable treatment element  24  is transitionable between a first deflated free-form configuration and a second inflated configuration. Additionally, when deflating the inflatable treatment element  24 , a vacuum source or pump (not shown) disposed within the console  14 , or in communication with the console  14 , may initiate the return or suctioning of fluid from the inflatable treatment element  24  and through the lumen defined by the shaft  16 . The suctioned fluid travels between a gap, chamber, or space defined between the inner wall of the shaft  16  and the fluid supply lumen  40 . The fluid is suctioned back towards a fluid recovery reservoir and/or scavenging system (discussed in more detail below) disposed within, or external to, the console  14 . 
     Continuing to refer to  FIG.  1    and  FIGS.  2 A- 2 B , the treatment element  24  can be biased to a spiral, helical, or otherwise coiled shape, which can be predefined, or the treatment element  24  may be torqueable or otherwise deformable (e.g., by inflation of the treatment element  24 ). When in the second inflated configuration, the inflatable treatment element  24  may also define a coiled structure having a plurality of loops  28  (shown in  FIG.  1   ) that are sized and configured to be in contact with the patient’s gallbladder wall. Following the completion of a treatment or ablation procedure, the dispersed fluid may pass from the inner chamber  46  of the inflatable treatment element  24 , through the lumen of the shaft  16  towards the proximal portion  18 , and to a fluid recovery reservoir  50  and/or scavenging system so that the inflatable treatment element  24  can return to its deflated free-form configuration. 
     Further, the fluid recovery reservoir  50  and/or scavenging system referenced to herein may be physically located within or external to the console  14  (as shown in  FIG.  1   ). In one configuration, the console  14  includes the fluid supply reservoir  38 , the fluid recovery reservoir  50  for recovering or venting expended fluid for re-use or disposal, and various control mechanisms. In addition to providing an exhaust function for the fluid supply, the console  14  may also include pumps, valves, controllers or the like to recover and/or re-circulate fluid delivered to the shaft  16  and/or the fluid pathways of the system  10 . Further, the console  14  may include a vacuum pump for creating a low-pressure environment in one or more conduits within the device  12  so that refrigerant is drawn into the conduit(s)/lumen(s) of the shaft  16 . However, as mentioned above, the fluid supply reservoir  38 , the fluid recovery reservoir  50 , or scavenging system may instead be separate from, but in communication with, the console  14 . 
     Now referring to  FIG.  3   , the medical device  12  includes a plurality of shafts  16  and a plurality of treatment elements  24  coupled to and/or contiguous with the distal end  27  of each respective shaft  16  to have an enhanced cooling distribution of refrigerant. In some configurations, each shaft  16  of the plurality of shafts is coupled, adhered, or otherwise bonded to at least one adjacent shaft  16 . In other configurations, not shown, the plurality of shafts  16  may be disposed within a lumen having a plurality of isolated channels each sized and configured to receive one shaft  16  of the plurality of shafts. Each individual inflatable treatment element  24  can bring pressured refrigerant towards its distal tip  56  to maximize output over a shorter length or distance. In some embodiments, the device  12  may include five inflatable treatment elements  24  and five shafts  16 . Each shaft  16  may have an independent fluid supply lumen  40  that extends through a respective inflatable treatment element  24  coupled to, and/or contiguous with, the distal end  27  of the shaft  16  and is in communication with the console  14 . Each inflatable treatment element  24  is transitionable between the first deflated free-form configuration and the second inflated configuration. However, it is to be understood that the device  12  may include more or less than five inflatable treatment elements  24  as deemed necessary by the clinician to achieve a desired ablative efficacy or pattern. As shown in  FIG.  3   , when in the second inflated configuration, each inflatable treatment element  24  may define at least one loop  28  or spiral that is sized and configurated to approximate or substantially match the curvature of the gallbladder wall. 
     Continuing to refer to  FIG.  3   , each inflatable treatment element  24  may be spaced apart from an adjacent inflatable treatment element  24  so that no two inflatable treatment elements are in physical contact with each other. Further, the inflatable treatment elements  24  may be inflated such that each inflatable treatment element  24  has a diameter that is the same as or different than an outer diameter of another inflatable treatment element. For example, some embodiments having five inflatable treatment elements  24  defining five loops  28 , one respective loop  28  may have an outer diameter that is larger or smaller than the outer diameter of the other remaining loops. 
     As shown in  FIGS.  1  and  3   , each inflatable treatment element  24  includes a plurality of electrodes  52  in communication with the console  14  and configured to monitor a quality, level, or degree of contact between each inflatable treatment element  24  and the area of target tissue within the gallbladder wall and the growth of ice on the target tissue during a cryoablation procedure. Cryoablation may be referred to as the treatment of target tissue with thermal energy, and in particular, involves delivering cryogenic fluid to the inflatable treatment element  24  at a low enough temperature to extract heat from the target tissue, thereby ablating the target tissue. During or following the cryoablation procedure, some or all of the plurality of electrodes  52  may transmit an impedance signal to the area of target tissue within the gallbladder wall and measure or record a subsequent response indicative of the biological electrical activity within the area of target tissue. The measured response may be referred to as at least one impedance signal which may then be transmitted by the electrodes  52  to the console  14 . The console  14  may either store the received impedance signal within the memory of the processing circuitry  34 , or it may be used immediately for subsequent processing. For example, the processing circuitry  34  is configured and/or programmed to determine a degree of tissue contact between the inflatable treatment element  24  and the gallbladder wall based, in part, on the at least one impedance measurement signal, and relay the information to the patient and/or clinician via the  36  display, computer monitor, smartphone screen, or the like. 
     Continuing to refer to  FIGS.  1  and  3   , the plurality of electrodes  52  may be disposed along, coupled to, or otherwise printed on the outer surface  54  of the inflatable treatment element  24 . In some embodiments, each electrode of the plurality of electrodes  52  may be a ring electrode or button electrode printed or coupled to the outer surface  54  of the inflatable treatment element  24 . Each electrode  52  may be in electrical communication with a flexible tracing or wire (not shown) that is in electrical communication with the console  14 . Alternatively, more than one electrode  52  may be in communication with a single tracing or wire. Also, in some embodiments, the plurality of electrodes  52  may be uniformly spaced apart along the outer surface  54 . However, it is to be understood that the plurality of electrodes  52  may also be positioned such that a distance between each electrode  52  in a first pair of adjacent electrodes is different than a distance between each electrode  52  in a second pair of adjacent electrodes. In other words, in some configurations, the spacing between electrodes may be uniform, and in other configurations, the spacing between electrodes may not be uniform. The plurality of electrodes  52  may be flexible, stretchable, and/or may not be cinched down on the outer surface of the treatment element  24 . In some such configuration, the electrodes  52  and/or the tracings may be printed in a zig-zag, spiral, helical, radial, or offset pattern along the length of the treatment element  24 . 
     Now referring to  FIGS.  4 A- 4 B , in some embodiments, the medical device  12  may be used in combination with a second medical device that includes a guide sheath  58 . The guide sheath  58  is an elongate body that is sized and configured to be passed through the patient’s body and aids in positioning the medical device  12  within the gallbladder. This guide sheath  58  can be advanced after percutaneous access through the patient’s chest, through the liver, through the gallbladder wall, and placement of a guidewire  23  within the gallbladder are performed. As shown in  FIGS.  4 A- 4 B , the guide sheath  58  includes a distal end  60  that defines an opening. The shafts  16  of the medical device  12  may be inserted and navigated through a lumen  62  of the guide sheath  58  until the distal end  27  of each shaft  25  is proximate to or coterminous with the distal end  60  of the guide sheath  58 . Once navigated through the guide sheath  58 , the plurality of inflatable treatment elements  24  are positioned near the area of target tissue within the gallbladder or gallbladder wall. Each inflatable treatment element  24  is biased to a spiral, helical, or otherwise coiled shape as it is inflated such that the outer surface of the treatment element  24  is in contact with multiple tissue surfaces within the gallbladder. Further, it is to be understood that although the guide sheath  58  is only illustrated in  FIGS.  4 A- 4 B , the guide sheath  58  may also be used with the device  12  that is shown in  FIGS.  1 - 3    and described herein. 
     Now referring to  FIG.  5   , in which an exemplary method of ablating an area of target tissue within a gallbladder having a gallbladder wall. The method includes first positioning a medical device  12  having an inflatable treatment element  24  proximate to the area of target tissue (Block S 500 ). The inflatable treatment element is transitionable between a first deflated free-form configuration and a second inflated coiled configuration. Once the device  12  is in the desired position, cryogenic fluid may be circulated within the inflatable treatment element  24  during an ablation phase such that the inflatable treatment element  24  transitions to the second inflated configuration and an outer surface  54  of the inflatable treatment element  24  is at least in partial contact with an inner surface of the gallbladder wall (Block S 502 ). During or after the ablation phase, at least one impedance measurement signal may be recorded or measured by at least one electrode of the plurality of electrodes  52  (Block S 504 ). The recorded impedance measurement signal may then be transmitted from the electrode(s)  52  to the console  14  for processing and/or storage in the memory (Block S 506 ). The console  14  then determines a degree of tissue contact between the inflatable treatment element  24  and the inner surface of the gallbladder wall based, in part, on the at least one impedance measurement signal (Block S 508 ) and relays the relevant information to the patient and/or clinician via the external display unit  36 . 
     Although the device  12  is described herein as operating to reduce the temperature of target tissue in order to ablate tissue within the gallbladder and gallbladder wall, it will be understood that the device  12  may also be used with one or more additional modalities, such as radiofrequency (RF) ablation, pulsed electric field ablation, ultrasound ablation, microwave ablation, or the like. 
     It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device. 
     In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which corresponds to a tangible medium such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer). 
     Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” as used herein may refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements. 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.