Patent Application
20250221754
Medical ablation technologies, such as those used in cardiology, oncology, general surgery, gastroenterology, dermatology, and interventional radiology, focus on local tissue targets and, while providing a great degree of ablation depth control, may not be effective or practical for large, high-surface area (HSA) tissue ablation targets within a body. Cryoablation technologies leverage a generic cryogen spray to provide a platform for HSA tissue ablation, but have certain drawbacks associated with safely and effectively delivering energy within closed lumens, such as the gallbladder. For example, ice build-up or other complications during an ablation procedure can lead to injury and/or ineffective ablation. Accordingly, it is desirable to have systems, devices, and methods to address the drawbacks of existing ablation systems.
The present disclosure relates to devices and methods for ablation and defunctionalization of a gallbladder with temperature feedback.
In some embodiments, an apparatus includes a shaft including a nozzle disposable within a body lumen of a subject, the shaft defining: an ablation medium delivery lumen in fluid communication with the nozzle, the ablation medium delivery lumen configured to deliver an ablation medium to the nozzle, the nozzle configured to distribute the ablation medium throughout the body lumen such that the ablation medium contacts and ablates tissue within the body lumen; a first pressure lumen having a distal opening that terminates in the body lumen when the nozzle is disposed in the body lumen, the first pressure lumen configured to couple a first pressure sensor disposed proximal to the shaft to the body lumen such that the first pressure sensor can measure an intraluminal pressure of the body lumen; and a second pressure lumen having a distal opening that terminates in an evacuation lumen configured to evacuate a portion of the ablation medium from the body lumen, the second pressure lumen configured to couple a second pressure sensor disposed proximal to the shaft to the evacuation lumen such that the second pressure sensor can measure a pressure in the evacuation lumen.
In some embodiments, an apparatus includes an outer shaft defining an evacuation lumen, the outer shaft having a distal portion disposable within a body lumen of a subject, the evacuation lumen configured to evacuate an ablation medium from the body lumen; an inner shaft including a nozzle configured to distribute the ablation medium throughout the body lumen such that the ablation medium contacts and ablates tissue within the body lumen, the inner shaft disposable within the evacuation lumen and configured to extend out from the evacuation lumen such that the nozzle is disposed distal to a distal end of the outer shaft, the inner shaft defining: an ablation medium delivery lumen in fluid communication with the nozzle, the ablation medium delivery lumen configured to deliver the ablation medium to the nozzle such that the nozzle can distribute the ablation medium throughout the body lumen; and a sensor lumen having a distal opening that terminates in the body lumen when the nozzle is disposed distal to the distal end of the outer shaft, the sensor lumen configured to couple a sensor to the body lumen such that the sensor can measure a property associated with the body lumen.
In some embodiments, an apparatus includes a shaft having a distal end that is disposable within a body lumen of a subject, the shaft defining (1) an ablation medium delivery lumen configured to deliver an ablation medium into the body lumen and (2) a pressure lumen having a distal opening that terminates in the body lumen when the distal end of the shaft is disposed within the body lumen; a pressure sensor coupled to the body lumen via the pressure lumen, the pressure sensor configured to measure an intraluminal pressure of the body lumen; a valve disposed within the ablation medium delivery lumen, the valve configured to transition between an open state to allow the ablation medium to the be delivered into the body lumen and a closed state to prevent the ablation medium from being delivered into the body lumen; and a control unit operatively coupled to the pressure sensor and the valve, the control unit configured to control the valve based on the intraluminal pressure measured by the pressure sensor.
In some embodiments, a method includes receiving an ablation fluid into a delivery lumen of a first shaft having a distal end disposed in a gallbladder lumen of a subject, conveying, via the delivery lumen of the first shaft, the ablation fluid to the distal end of the first shaft; dispensing the ablation fluid from the distal end of the first shaft such that the ablation fluid transitions into an ablation gas that contacts and ablates tissue within the gallbladder lumen; evacuating, via an evacuation lumen of a second shaft, at least a portion of the ablation gas from the gallbladder lumen; measuring an intraluminal pressure of the gallbladder lumen via a pressure sensor operatively coupled to a pressure lumen of the first shaft, the pressure lumen having a distal opening that terminates in the gallbladder lumen when the distal end of the first shaft is disposed in the gallbladder lumen; and controlling delivery of the ablation fluid to the distal end of the first shaft based on the intraluminal pressure of the gallbladder lumen.
The present disclosure relates to ablation systems, devices, and methods for ablating a body lumen, such as, for example, a gallbladder lumen. In some embodiments, systems, devices, and methods described herein relate to cryoablation devices for tissue ablation. In some embodiments, systems, devices, and methods described herein relate to ablation medium release valves, e.g., for catheter-based cryoablation devices, that are designed to safely, effectively, and uniformly disperse an ablation medium (e.g., a cryogenic ablation medium) onto an area of interest (e.g., tissue lining a gallbladder lumen). In some embodiments, systems, devices, and methods described herein relate to controlling an operation of an ablation system based on sensor data, e.g., pressure and/or temperature data. In some embodiments, systems, devices, and methods described herein include sensors and/or can be used with sensors (e.g., of one or more probes) to track properties or conditions of a body lumen (e.g., a gallbladder lumen) and/or an ablation medium being delivered into the body lumen. Examples of suitable components of ablation systems, including cryoablation devices, are described in International Patent Application No. PCT/US2019/017112, entitled “GALLBLADDER DEFUNCTIONALIZATION DEVICES AND METHODS,” filed on Feb. 7, 2019, and International Patent Application No. PCT/US2021/045987, entitled “SYSTEMS, DEVICES, AND METHODS FOR ABLATION AND DEFUNCTIONALIZATION OF A GALLBLADDER,” filed on Aug. 13, 2021, the disclosures of each of which are incorporated by reference in their entireties.
Gallstones are one of the most common gastrointestinal disorders amongst Americans. Gallstones form when bile, a fluid secreted by the liver and stored in the gallbladder, becomes supersaturated. While they do not cause a problem for many people, gallstones occasionally block the cystic duct, i.e., an outlet of the gallbladder, preventing the gallbladder from emptying. In some instances, the obstruction results in pain, inflammation, and infection. In otherwise healthy patients, the gallstone disease is treated by surgical removal of the gallbladder. However, the risks associated with surgical treatment are considerably higher in certain patient populations. For example, one in five Medicare patients have been shown to suffer an adverse outcome. Non-surgical treatment options for these patients are limited and focus on relieving acute symptoms, without addressing the underlying cause of the disease. In some instances, the disease is likely to recur, resulting in additional clinical risk and significant cost. There currently is no long-term solution for gallbladder disease in high-risk patients.
As depicted in
Histologically, the gallbladder has 4 layers, including the serosa (the outermost layer), a muscular layer, lamina propria, and the innermost mucosa layer. The mucosal layer of the gallbladder is the innermost layer of the gallbladder wall and concentrates the bile. The serosa is derived from the visceral peritoneum and covers the anterior fundus, body, and neck of the gallbladder. Inside the serosa, a single muscular layer envelopes the lamina propria. The mucosa that lines the inner lumen of the gallbladder is composed of columnar epithelial cells which secrete mucin and dehydrate bile via the action of multiple ion channels. Occasionally, outpouchings (known as Rokitansky-Aschoff nodules) of the mucosa extend into deeper layers of the gallbladder wall.
The gallbladder stores and concentrates the bile produced by the liver and releases the stored bile into the small intestine, where the bile helps in the digestion of fats in food. Bile is made by hepatocytes in the liver and subsequently secreted into hepatic ductules which coalesce into intrahepatic ducts. These ducts converge to form the right and left hepatic ducts which then combine into the common bile duct. The common bile duct joins with the pancreatic duct just proximal to the ampulla of Vater in the duodenal wall. Bile produced by hepatocytes flows through the biliary system and into the duodenal lumen to aid in digestion.
Flow into the duodenal lumen is regulated at the level of the ampulla of Vater by the sphincter of Oddi. During an unfed state, when bile is not needed for digestion, the sphincter is closed, resulting in routing of bile to the gallbladder for storage. During storage, bile becomes supersaturated, providing a nidus for the formation of gallstones and sludge (very small gallstones). The majority of gallstones are “brown stones,” that are mainly comprised of cholesterol (typically >80%). These stones tend to be brittle and are readily crushed. A minority of stones are predominantly bilirubin (“black stones”; <20% cholesterol) and are often much harder. Mixed stones contain a variable amount of bilirubin and cholesterol.
Mobile gallstones that remain in the lumen of the gallbladder have the potential to cause various pathologies. In some instances, the gallstones become lodged at the neck of the gallbladder, occluding the cystic duct. The lodged gallstones cause gallbladder distension and intermittent right upper quadrant discomfort (likely from intramural muscle spasm at the organ attempts to empty against an increased pressure gradient), a condition known as symptomatic cholelithiasis. In some instances, the gallstones become lodged more permanently at the gallbladder outlet, resulting in inflammation and infection. This is a condition known as cholecystitis, which requires urgent intervention as it can progress to systemic infection.
Alternatively or in combination, gallstones or sludge passes through the cystic duct, becoming lodged in the common bile duct, blocking the flow of bile, resulting in a potentially life threatening condition known as ascending cholangitis. In some embodiments, the debris becomes lodged at the confluence of the pancreatic and common bile ducts, causing stagnation of pancreatic secretions, resulting in pancreatitis (inflammation of the pancreas).
In cholelithiasis, supersaturation of bile in gallbladder leads to the formation of gallstones. In some instances, impacted gallstones leads to inflammation, pain and infection of the gallbladder. When the gallbladder is inflamed, the mucosal layer of the gallbladder becomes more prominent. In some instances, the gallstone disease is diagnosed by ultrasounds or other imaging methods. Provided herein are methods and devices configured to definitively treat benign gallbladder disease in a minimally invasive manner in patients with symptomatic gallstones in order to reduce health care costs and patient morbidity.
Laparoscopic cholecystectomy is a treatment for gallstone disease and is a commonly performed general surgery procedure. During laparoscopic cholecystectomy, small incisions are made in the abdomen, facilitating the removal of the gallbladder with a camera and small instruments. The procedure is safe in otherwise healthy patients, and often does not require hospital admission. In uncomplicated cases, patients are often back to work within two weeks.
In a number of patient populations, the surgical risk associated with laparoscopic cholecystectomy is considerably higher. In some instances, these populations include critically ill patients, patients with intra-abdominal scarring from chronic disease and previous surgery, and elderly patients who tend to have a higher incidence of medical comorbidities. One such population is the Medicare population, which comprises approximately 200,000 laparoscopic cholecystectomies per year in the US. Twenty one percent of these surgeries result in an adverse outcome, including prolonged length of stay and readmission and other perioperative complications. In addition to the direct costs associated with these complications, many elderly patients are at risk of not returning to their baseline level of health, resulting in additional healthcare costs.
There are non-surgical options to treat gallstone disease. These include the administration of antibiotics, or placement of a cholecystostomy tube to drain the gallbladder contents, or a combination of the two. However, the non-surgical options do not provide a long-term solution. These options are effective temporizing measures, and they do not treat the cause of the disease. During a percutaneous cholecystostomy, a cholecystostomy tube is placed through the rib cage into the gallbladder. The percutaneous cholecystostomy can take place in an interventional radiology (IR) suite or at the patient's bedside but does not provide a definite treatment of the gallstone disease. Often times, the non-surgical options lead to recurrence and additional hospitalization costs.
For patients with cholecystitis who have a high risk of surgical complications, the treatment is percutaneous decompression of the gallbladder (via a percutaneously inserted cholecystostomy tube) in conjunction with antibiotics. This treatment provides a temporizing measure to allow the patient to recover from the systemic effects of the ongoing infection (sepsis) and return to their baseline state of health (commonly referred to as “cooling off” by healthcare professionals). The cholecystostomy tube remains in place until the patient has recovered. About 6-8 weeks following placement, a cholangiography by injection of radiopaque contrast through the tube under fluoroscopy is performed to determine if the cystic duct is patent (open). The cholecystostomy tube is removed if the cystic duct is patent. The treatment is interval cholecystectomy as it reduces the rate of recurrence of the gallstone disease. If there is no communication between the cystic duct and the common bile duct, the tube remains in place until cholecystectomy is performed, or patency is demonstrated on subsequent cholangiography. There is no definitive treatment available for high risk patients, placing them at risk for disease recurrence and exposure to the associated clinical risks and healthcare costs.
Ablation technologies have been used to treat other diseases. For example, ablation has been used in treatment of esophageal metaplasia and endometrial hyperplasia. However, ablation technologies are not readily available for treating gallstone disease. Ablation technologies often are applied to a small targeted area, such as a nerve, and are not typically used for applying to a diffuse area or a tissue or organ. Systems, devices, and methods described herein relate to ablating and defunctionalizing a gallbladder, and are specifically designed to safely and efficiently ablate the gallbladder.
The control unit 110 can be operatively coupled to the ablation medium supply 120, which provides a supply of an ablation medium. For example, the control unit 110 can be configured to control delivery of the ablation medium into a body lumen (e.g., gallbladder lumen). In some embodiments, the ablation medium is a cryogenic ablation medium. In some embodiments, the cryogenic ablation medium is a liquid. In some embodiments, the cryogenic ablation medium is a gas. In some embodiments, the cryogenic ablation medium undergoes a liquid-to-gas phase transition when being delivered using the systems and devices disclosed herein. In some embodiments, cryoablation is achieved via the refrigerant property due to the liquid to gas phase change from an ablation medium, such as liquid nitrous oxide, carbon dioxide, and argon. In some embodiments, the cryogenic ablation medium is one or more of nitrous oxide, nitrogen, carbon dioxide, or argon. In some embodiments, the cryogenic ablation medium can transition from a first state (e.g., a liquid) to a second state (e.g., a gas) and increase up to about 600 times an original volume of the cryogenic medium during the transition. In some embodiments, the control unit 110 can control one or more of a temperature, a pressure, etc. of the ablation medium. In some embodiments, an ablation medium such as a cryogenic ablation medium ranges from about −120 degrees Celsius to about 0 degrees Celsius, including all values and subranges in between, when the cryogenic ablation medium is used with the systems and devices disclosed herein.
The control unit 110 can optionally be coupled to a vacuum source 140 (e.g., a vacuum or suction pump, an aspirator, etc.). In some embodiments, the control unit 110 can control the vacuum source 140 to apply a vacuum to a channel or lumen of the catheter system 150, e.g., to remove or evacuate an ablation medium from within a body lumen (e.g., gallbladder lumen). For example, the control unit 110 can activate the vacuum source 140 to apply negative pressure within a lumen of the catheter system 150 to evacuate a portion of an ablation medium, such as a cryogenic ablation medium, that has been delivered to the body lumen. Alternatively, in some embodiments, the ablation system 100 does not include a vacuum source 140, and ablation medium can be evacuated from a body lumen via passive evacuation driven by a pressure differential between an interior of the body lumen and an exterior environment. For example, when an ablation medium such as a cryogenic ablation medium is delivered into a body lumen, the ablation medium can increase pressure within the body lumen relative to an environment exterior to the body lumen (e.g., an exterior atmosphere), and that pressure differential can drive evacuation of a portion of the ablation medium out of the body lumen, e.g., via a lumen defined by the catheter system 150.
In some embodiments, the control unit 110 can include or be operatively coupled to one or more sensors (e.g., pressure sensors, temperature sensors), and can operate or control one or more components of the ablation system 100 based on data collected by the one or more sensors. For example, the control unit 110 can be coupled to a pressure sensor and, based on measurements from the pressure sensor, control delivery of the ablation medium (e.g., from ablation medium supply 120) and evacuation of the ablation medium (e.g., using vacuum source 140) to maintain pressure within a body lumen within a predetermined range of pressures. Stated differently, the control unit 110 can be configured to control insufflation of a body lumen such that pressure within the lumen is maintained within a predetermined range of pressures. In some embodiments, the predetermined pressure range is less than 50 mmHg, or less than 100 mmHg. In some embodiments, the predetermined pressure range is about 0 mmHg to about 40 mmHg, or about 30 mm Hg to about 40 mm Hg. In some embodiments, the control unit 110 can be operatively coupled to one or more valves, which the control system 110 can control to allow and/or terminate delivery or evacuation of an ablation medium. Further details of such control mechanisms are described with reference to
In some embodiments, the control unit 110 and/or other components of the ablation system 100 can optionally be coupled to one or more additional compute devices 190. Compute device(s) 190 can be can be any suitable processing device configured to run and/or execute certain functions. The one or more compute device(s) 190 can include, for example, a computer, a laptop, a portable device, a mobile device, or other suitable compute device including a processor, a memory, and/or an input/output device. For example, the control unit 110 can be coupled to a remote compute device, such as a workstation, through which a user (e.g., physician, administrator, etc.) can control one or more operational parameters of the ablation system 100. The control unit 110 and the one or more compute device(s) 190 can be configured to send data and/or receive data from one or more other compute device(s) 190, e.g., via a network. For example, the control unit 110 can send alerts and/or other information to a remote device (e.g., a display, a mobile device) such that the remote device can present that information to a user (e.g., a physician). In some embodiments, the control unit 110 can send data such as patient information, operational status of one or more components of the ablation system 100, etc.
In some embodiments, the control unit 110 can be integrated into a handheld device that is attached to a proximal end of the catheter system 150. The handheld device can include on or more input and/or output devices (e.g. buttons, switches, keyboards, touchscreens, display, etc.) through which an operator of the ablation system 100 can control the operation of the ablation system 100 to perform an ablation procedure. In some embodiments, the control unit 110 can be remote from the catheter system 150, and a remote operator can control one or more components of the ablation system 100 to perform an ablation procedure.
The catheter system 150 can be percutaneously inserted into a body lumen (e.g., a gallbladder lumen) to scar down and defunctionalize portions of anatomy (e.g., the gallbladder) without the need for surgical removal of the anatomy. The catheter system 150 can be used in the interventional radiology (IR) suite and with local anesthesia, eliminating the risks associated with general anesthesia in high risk surgical patients. Placement of the device leverages existing IR workflows and can be deployed in a manner similar to existing devices. For example, for placement in the gallbladder lumen, such placement can be similar to a cholecystostomy tube or percutaneous gallbladder drainage tube.
In some embodiments, the lumen 262 can be configured to evacuate or drain fluids (e.g., liquids or gases) and/or debris (e.g., gallstones or fragments thereof, tissue, etc.) from within the body lumen BL. For example, the lumen 262 can allow an ablation medium (e.g., a cryogenic ablation medium) delivered to the body lumen BL to be evacuated from the body lumen BL. In some embodiments, the lumen 262 can be operatively coupled to a vacuum source 240, which can be activated to apply negative pressure within lumen 262 to evacuate fluid from within the body lumen BL. Alternatively, the lumen 262 can function as a passive evacuation passageway for fluid to exit the body lumen BL. For example, as ablation medium is delivered into the body lumen BL and pressure increases within the body lumen BL relative to an exterior of the shaft 260, such pressure can passively drive a portion of the ablation medium out from the body lumen BL via lumen 262.
In some embodiments, the outer shaft 260 can define one or more additional lumens, e.g., a lumen 264, which can be structurally and/or functionally similar to lumen 262. For example, lumen 264 can also be configured to provide access into the body lumen BL. In some embodiments, lumen 262 can be configured to receive the inner shaft 270 and lumen 264 can be configured to receive a different surgical and/or monitoring device (e.g., a probe, a second ablation device, etc.). In some embodiments, one or more of lumens 262, 264 can be fluidically coupled to a sensor (e.g., a pressure sensor) to allow for pressure measurements of the body lumen BL and/or other portions of the body. For example, a sensor integrated into a control unit (e.g., control unit 110) can be in fluid communication with one or more of lumens 262, 264 and take measurements (e.g., pressure measurements) of an environment within the outer shaft 260 and/or body lumen BL.
In some embodiments, the outer shaft 260 optionally includes a sensor 263. In some embodiments, the sensor 263 can be located in a distal portion of the outer shaft 260 that is configured to be disposed within the body lumen BL. Alternatively, the sensor 263 can be disposed at a different location along the outer shaft 260, including, for example, within a lumen (e.g., lumen 262, 264), at a proximal end at the outer shaft 260, etc. The sensor 263 can be configured to capture information about an environment within the body lumen BL or other environment within and/or surrounding the outer shaft 260. For example, the sensor can be configured to measure a property (e.g., pressure, temperature) of an ablation medium being delivered to the body lumen BL, a property (e.g., pressure, temperature) of the body lumen BL or fluid within the body lumen BL, etc. The sensor 263 can include, for example, a pressure sensor (e.g., pressure transducer, strain gauge transducer, diaphragm displacement sensor, optical fiber pressure sensor, solid state sensor), temperature sensor, light sensors, gas sensors, etc. In some embodiments, sensor 263 can be coupled to a control unit (e.g., control unit 110) and/or other compute device (e.g., compute device 190) via a wired connection, such as, for example, a wire that is coupled to and/or disposed within the outer shaft 260. In some embodiments, the sensor 263 can be configured to wirelessly transmit data, e.g., indicative of one or more measured properties of the body lumen BL, to control unit and/or another compute device.
In some embodiments, the outer shaft 260 includes an expandable member or structure 266 that can be deployed within the body lumen BL, e.g., transitioned from an undeployed sate to a deployed or expanded state. The expandable structure 266 can be configured to prevent dislodgement and/or create a seal between the outer shaft 260 and the body lumen BL. In use, the outer shaft 260 can be advanced, e.g., along a guidewire, until a distal end of the outer shaft 260 is positioned within the body lumen BL through an opening. The expandable structure 266 can then be deployed (e.g., expanded, inflated), as schematically shown in
While two lumens (e.g., lumens 262, 264) are depicted in
In some embodiments, the inner shaft 270 can be configured to deliver thermal ablation, cryoablation, chemical ablation, or any combination thereof. In some embodiments, cryoablation involves delivering a low temperature fluid to wall of the gallbladder, such as liquid nitrogen. In some embodiments, cryoablation involves delivering an ablation medium to the gallbladder wall that induces low temperatures due to phase change, such as nitrous oxide or carbon dioxide. In some embodiments, thermal ablation involves delivering a high temperature fluid to the wall of the gallbladder, such as, for example, hot water or steam. In some embodiments, the ablative medium is delivered in a liquid form, a gaseous form, an aerosol form, a gel form, or any combination thereof.
The inner shaft 270 can define a lumen 272. The lumen 272 can be configured to deliver an ablation medium, e.g., from ablation medium supply 220, to a nozzle 274 that is disposable within the body lumen BL. The nozzle 274 can be configured to release the ablation medium into the body lumen BL. In some embodiments, the nozzle 274 can include a plurality of openings or fenestrations for distributing the ablation medium throughout the body lumen BL. In some embodiments, the lumen 272 and nozzle 274 can be configured to convey a cryogenic ablation medium in a liquid state into the body lumen BL. The lumen 272 and nozzle 274 can be configured with dimensions that maintain a set amount of pressure on the cryogenic ablation medium such that the medium does not undergo a liquid-to-gas transition until the ablation medium exits the openings of the nozzle 274. Stated differently, the lumen 272 and nozzle 274 can be configured to convey a cryogenic ablation medium in a liquid state to the openings of the nozzle 274, at which point the release of the cryogenic ablation medium into the body lumen BL results in the cryogenic ablation medium changing from the liquid state into a gas state. In some embodiments, the lumen 272 of the inner shaft 270 can have a diameter from about 0.001 inches to about 0.1 inches, including all values and subranges in between.
In some embodiments, the inner shaft 270 can optionally include a valve 278. The valve 278 can be configured to control delivery of the ablation medium into the body lumen BL. For example, the valve 278 can be configured to turn on or shut off supply of the ablation medium into the nozzle 274. In some embodiments, a control unit (e.g., control unit 110) can be configured to control opening and/or closing of the valve 278. In some embodiments, a mechanical actuator (e.g., coupled to a handheld device, as described above) can be used to open and/or close the valve 278. In some embodiments, the valve 278 can be configured to close (e.g., automatically and/or via control by a control unit) in response to a pressure within the body lumen BL being greater than a predetermined threshold. In some embodiments, a sensor (e.g., sensor disposed on inner or outer shaft 260, 270 and/or sensor coupled to control unit 110) can be used to measure the pressure within the body lumen BL and control the valve 278 to open and/or close. In some embodiments, the valve 278 can be configured to close in response to a pressure difference between the body lumen BL and an evacuation lumen (e.g., lumen 262), e.g., indicating that a blockage or obstruction has formed along an evacuation pathway. For example, multiple sensors can be configured to measure different pressures associated with the catheter system 250 and/or body lumen BL, and a control unit (e.g., control unit 110) can be configured to analyze when such pressure measurements to determine when an unexpected obstruction has isolated any fluid flow paths into and/or out of the body lumen BL.
As noted above, in some embodiments, the inner shaft 270 can be or form part of a cryoablation device and be configured to deliver a cryogenic ablation medium into the body lumen BL. The cryoablation device can leverage the phase-change properties of certain cryogenic ablation mediums (e.g., liquid nitrous oxide) to induce cryoablation temperatures at a target tissue interface. When such cryogenic ablation mediums transition from liquid to gas, they expand in volume and can cause increase in pressure within the body lumen BL. Therefore, one important consideration in designing systems and devices disclosed herein lies in the monitoring and control of the intraluminal pressure in the body lumen BL during an ablation procedure. For example, systems and devices disclosed herein can be configured to ensure that intraluminal pressure does not increase above a predetermined threshold and/or lies within a predetermined range. In instances where there is an increase in intraluminal pressure (e.g., pressure above a predetermined threshold, or sudden change in pressure above a predetermined rate), systems and devices disclosed herein can be configured to evacuate air, gaseous cryoablation medium, and/or other fluids from within the body lumen BL to reduce the intraluminal pressure. In such instances, it can be important to ensure to any cryogenic ablation medium within the catheter system 250 (e.g., within lumen 272 of the inner shaft 270) and/or supply line into the catheter system 250 does not exit the catheter system 250 (e.g., nozzle 274) into the body lumen BL, further adding to the pressure increase. Accordingly, it can be desirable to minimize or reduce the amount of residual cryogenic ablation medium that is delivered into the body lumen BL in response to detecting a pressure increase event (e.g., pressure above a predetermined threshold, or sudden change in pressure above a predetermined rate). In some embodiments, the valve 278 can be used to reduce the amount of residual cryogenic ablation medium that is delivered into the body lumen 270. The valve 278 can be positioned at or near the nozzle 274 such that the valve 278, upon closing, prevents any residual or excess ablation medium within the lumen 272 and/or other passageways leading to the nozzle 274 from being delivered into the body lumen BL.
The valve 278 can include any range of suitable mechanisms. In some embodiments, the valve can be closed in its resting state but can open to allow ablation medium to be delivered into the body lumen BL. Alternatively, the valve 278 can be open in its resting state and can be closed to prevent additional ablation medium from being delivered into the body lumen BL. In some embodiments, the valve 278 can be biased closed and/or open using a spring mechanism. The valve 278 can have any suitable geometry including, for example, a cube, cone, cylinder, triangular prism, torus, helix, ovoid, or other three-dimensional body with sufficient structure to impede ablation medium flow. In some embodiments, the valve 278 can be seated against a valve seat defined within the inner shaft 270 (e.g., within lumen 272). In some embodiments, the valve 278 can be actuated, either manually or via a control device (e.g., control device 110), with a drive wire or rod, pneumatic or hydraulic pressure, electromagnetic force, and/or motor to open and/or close. Further details of example valve designs are described with reference to
In some embodiments, the inner shaft 270 optionally includes a sensor 273. In some embodiments, the sensor 273 can be located in a distal portion of the inner shaft 270 that is configured to be disposed within the body lumen BL. Alternatively, the sensor 273 can be disposed at a different location along the inner shaft 270, including, for example, within a lumen (e.g., lumen 272, 276), at a proximal end at the inner shaft 270, etc. The sensor 273 can be configured to capture information about an environment within the body lumen BL. For example, the sensor 273 can be configured to measure a property (e.g., pressure, temperature) of an ablation medium being delivered to the body lumen BL, a property (e.g., pressure, temperature) of the body lumen BL or fluid within the body lumen BL, etc. The sensor 273 can include, for example, a pressure sensor (e.g., pressure transducer, strain gauge transducer, diaphragm displacement sensor, optical fiber pressure sensor, solid state sensor), temperature sensor, light sensors, gas sensors, etc. Sensor 273 can be capable of communicating data (e.g., sensor measurements) to a control unit (e.g., control unit 110) and/or other compute device (e.g., compute device 190) via a wired or wireless connection.
In some embodiments, the sensor 273 can measure a temperature of an exhaust gas (e.g., a gas exiting the body lumen during an ablation procedure). The temperature of the exhaust gas can be indicative of a degree or state of ablation. In other words, the temperature of the exhaust gas can indicate whether an ablation of a body lumen is complete. The sensor 273 can measure this information and provide it to a controller or processor (e.g., control unit 110 or a dedicated heating element controller), which can then control ablation delivery based on such information. In some embodiments, the controller can be coupled to a heater or heating element 230. The controller can be configured to control the heating element 230 to modulate a refrigeration power of a cryogenic ablation medium. For example, the controller can be configured to activate or power on the heating element 230 to heat a portion of a cryogenic ablation medium delivery line, thereby reducing a refrigeration power of the cryogenic ablation medium being delivered therein. The controller can be configured to reduce the refrigeration power of the cryogenic ablation medium such that a temperature of the exhaust gas remains within a predefined range for a predefined period of time. It can be desirable to maintain the temperature of the exhaust gas (which can be indicative of a temperature of the body lumen) within a predefined range for a predefined period of time because such can be indicative of ablation completion. The heating element 230 can be disposed along a portion of a delivery line for delivering the cryogenic ablation medium. In some embodiments, the heating element 230 can be disposed outside of a patient's body, e.g., along a portion of a line coupling the inner shaft 270 to the ablation medium supply 220. In some embodiments, the heating element 230 can be implemented as a resistive heating coil wrapped around the delivery line. Alternatively or additionally, the heating element 230 can be implemented as a heated water jacket around the delivery line, inductive heating of a metal flow path, a Peltier chip or other thermoelectric device, or any other suitable type of heating element capable of conducting heat to the delivery line. Further details of the heating element 230, and the control thereof, are described with reference to
In some embodiments, the inner shaft 270 can optionally include one or more additional lumens 276. In some embodiments, a lumen 276 can configured as a passageway for relaying pressure information or other conditions (e.g., temperature) from the body lumen BL and/or other portions of the catheter system 250. For example, a first lumen 276 can be configured to extend or open into the body lumen BL, and a pressure sensor 211 (e.g., a sensor disposed or operatively coupled to a control unit, such as control unit 110) can be used to measure a pressure within the body lumen BL (i.e., the intraluminal pressure). As another example, a temperature sensor can be used to measure temperature within the body lumen via the lumen 276. A second lumen (not depicted) can be configured to extend or open into the evacuation lumen (e.g., lumen 262), and a pressure sensor can be used to measure a pressure within the evacuation lumen. In some embodiments, the lumen 276 can be configured to receive a guidewire and/or one or more additional instruments (e.g., temperature, pressure, or other sensor probes).
In some embodiments, the catheter system 250 can optionally include an occluder 279. Occluder 279 can be configure to occlude or close an opening or lumen outlet LO into nearby anatomical structures from the body lumen BL. For example, in the case where the body lumen BL is a gallbladder lumen, the occluder 279 can be configured to occlude a cystic duct. The occluder 279 can be coupled to and/or detachable from the inner shaft 270. In operation, the occluder 279 can be coupled to a distal end of the inner shaft 270. The inner shaft 270 can be navigated into the body lumen BL, e.g., via insertion through the outer shaft 260. The inner shaft 270 can be manipulated to position the occluder 279 at an opening out of the body lumen BL (e.g. outlet lumen such as a cystic duct). The occluder 279 can then be decoupled or ejected from the inner shaft 270, allowing the occluder 279 to be placed in the opening. The occluder 279 can subsequently be fixed in place, e.g., via volume expansion of the occluder 279, external threads, friction fit, adhesion, or other suitable fixation mechanism. Further details of suitable occluders such as, for example, plugs, are described in International Patent Application No. PCT/US2019/017112, incorporated herein by reference.
While two lumens (e.g., lumens 272, 276) are depicted in
The outer shaft 260, inner shaft 270, and/or probe 280 can be formed of flexible and/or semi-flexible material that enables each to be navigated to the body lumen BL, e.g., along a guidewire. The material can be a medical grade, biocompatible material.
Processor 312 of control unit 310 can be any suitable processing device configured to run and/or execute functions associated with deploying one or more components of a catheter system (e.g., advancing or retracting a shaft, deploying an expandable structure, opening and/or closing a valve), delivering ablation medium into a body lumen, analyzing sensor data associated with an ablation procedure involving the catheter system, controlling temperature and/or pressure within the body lumen, etc. Processor 312 can be configured to execute modules, functions, and/or processes. Processor 312 can be a general purpose processor, a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), and/or the like. In some embodiments, processor 312 is part of a circuit, e.g., such as an integrated circuit. In some embodiments, one or more other components of the ablation system can be integrated into the circuit, including, for example, one or more sensors.
Input/output interface 319 can include a user interface and/or communication interfaces for connecting the control unit 310 to one or more external compute devices. The user interface(s) can include one or more components that are configured to receive inputs and send outputs to other devices and/or a user operating a device, e.g., a user operating a catheter system. For example, the user interface can include a display device (e.g., a display, a touch screen, etc.), an audio device (e.g., a speaker or alarm), and one or more additional input/output device(s) configured for receiving an input and/or generating an output to a user. The communication interface(s) can include one or more wireless and/or wired interfaces, e.g., for communicating with other compute device (e.g., compute device(s) 190) via one or more networks (e.g., a local area network (LAN), a wide area network (WAN), a virtual network, a telecommunications network).
Memory 314 can be, for example, a random access memory (RAM), a memory buffer, a hard drive, a database, an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), a read-only memory (ROM), and/or so forth. In some embodiments, memory 314 stores instructions that cause processor 312 to execute modules, processes, and/or functions associated with deploying one or more components of a catheter system (e.g., advancing or retracting a shaft, deploying an expandable structure, opening and/or closing a valve), delivering ablation medium into a body lumen, analyzing sensor data associated with an ablation procedure involving the catheter system, controlling temperature and/or pressure within the body lumen, etc. Methods as described herein can be implemented by way of machine (e.g., computer processor) executable code stored on an electronic storage location of the control unit 310, such as, for example, on the memory 314, or a memory operatively coupled to the control unit 310. In some embodiments, the machine executable or machine-readable code is provided in the form of software. In operation, the code can be executed by the processor 312. In some cases, the code is retrieved from the memory 314 to be accessed and/or executed by the processor 312.
As depicted in
In the event a pressure buildup or increase is detected (e.g., pressure being above a threshold value or changing a predetermined percentage or amount), a user interface can alert the user, e.g., via an output device 419, with an audio, visual and/or haptic response. Alternatively, in some embodiments, the user is not notified but the processor 412 controls a valve 478 to terminate delivery of the ablation medium into the body lumen. In some embodiments, in the event of a pressure buildup event, the processor 412 can detect the event and directly interface with (e.g., control) the valve 478 to close within a predetermined period of time (e.g., about 0-10 seconds response time, inclusively), such that the flow of ablation medium into the body lumen BL is terminated. In at least one embodiment, one or more additional valves (not depicted) disposed closer to or at the ablation medium supply 420 can be used to shut off the flow of ablation medium from the ablation medium supply 420 into the lumen 472 (e.g., of a catheter system) as a secondary control measure.
In at least one embodiment, the space in the lumen 462 between the outer shaft and the inner shaft provides an evacuation path for gas volume within the target lumen. In at least one embodiment, one or more active and/or passive evacuation mechanisms, as described above with respect to
In at least one embodiment, the inner and/or outer shaft can be held stationary during an ablation procedure. In another embodiment, the at least a portion of the inner and/or outer shafts can be dynamic and move around within a two-dimensional plane and/or three-dimensional volume within the body lumen.
In some embodiments, the catheter system can be placed into a gallbladder lumen. Accessing the gallbladder with the catheter system can be achieved through a percutaneous approach. In some embodiments, an access sheath or outer shaft 760 of the catheter system accesses the gallbladder 2 through a transhepatic, percutaneous approach using ultrasound guidance, as seen in
After positioning the distal end of the outer shaft of the catheter system within the body lumen, the method 500 can optionally include deploying an expandable structure, at 504. Deploying the expandable structure within the body lumen can ensure that the outer shaft (e.g., access catheter, introducer) remains or is retained within the body lumen during the ablation procedure.
The method 500 can include advancing an inner shaft (e.g., inner shaft 270) of the catheter system into the body lumen, at 506. The inner shaft can be advanced until a nozzle (e.g., nozzle 274) of the inner shaft is disposed within the body lumen distal to a distal end of the outer shaft. The inner shaft can be advanced into the body lumen by inserting the inner shaft into a lumen defined by the outer shaft and advancing the inner shaft through that lumen until a distal portion of the inner shaft is disposed distal to the outer shaft. The distal portion of the inner shaft can include one or more openings (e.g., fenestrations) that can deliver ablation medium into the body lumen. In some embodiments, the method 500 can optionally include deployment of saline to lavage and drain any content within the body lumen, e.g., via inner and/or outer shafts. For example, fluid such as saline can be delivered into the gallbladder via a first lumen (e.g., lumen 272 defined by inner shaft 270) and/or content within the body lumen (e.g., gallbladder content) can be evacuated from the body lumen via a second lumen (e.g., lumen 262 defined by outer shaft 260).
The method 500 can optionally include occluding a nearby outlet of the body lumen (e.g., a cystic duct), at 507. For example, an occluder (e.g., occluder 279) can be positioned at the outlet lumen and deployed (e.g., ejected, expanded, etc.) to occlude the outlet lumen. The method 500 can optionally include opening a supply lumen valve (e.g., valve 278), at 508. For example, as discussed above with reference to
The method 500 can include delivering the ablation medium to the body lumen, at 510. In some embodiments, a cartridge (e.g., ablation medium supply source 120, 220) of a cryogenic ablation medium (e.g., nitrous oxide) or any other suitable ablation medium can be loaded into a handle (e.g., handheld device) of the ablation device. In the case of using a cryogenic ablation medium, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more than 10 freeze-thaw cycles can be delivered to the gallbladder, at 510, to ensure complete hypothermic death of the gallbladder mucosa. While delivering the ablation medium, method 500 can include events and/or steps associated with pressure and/or temperature monitoring, as further described below with reference to
The method 500 can optionally include generating information to present to a user, at 526. In some embodiments, the information presented to the user can be presented via a compute device, such as control unit 110 and/or 310, or other compute device in network communication with the ablation system (e.g., a tablet, smartphone, or any other suitable communication device). In some embodiments, to evaluate the temperature of tissue at a different location, the temperature sensor can optionally be moved to a new location, at 527. For example, the temperature sensor can be retracted from tissue a first location, moved to a second location, and inserted into tissue at a second location. At step 528, the method 500 can include determining if the ablation is completed based at least on the temperature measurements collected by the temperature sensor. If the ablation is completed (528: YES), the supply of ablation medium is terminated at 529, and then the method 500 can continue to 514. If the ablation is not completed (528: NO), the method can continue to monitor the temperature and status of ablation, by repeating 520-527.
At 514, the catheter system (e.g., introducer and ablation catheter) can be removed from the body lumen. For a time period (e.g., a few weeks) after the removal of the ablation system, the body's chronic inflammatory response can scar the ablated gallbladder tissue, leading to involution of the lumen and occlusion of the cystic duct. Bile flow can be shut off to the gallbladder, while its blood supply remains uncompromised, resulting in an inert organ.
In some embodiments, as described above, the ablation procedures described herein use a cryogenic ablation medium. In some embodiments, the cryogenic ablation medium is a liquid. In some embodiments, the cryogenic ablation medium is a gas. In some embodiments, the cryogenic ablation medium undergoes a liquid-to-gas phase transition when being delivered using the catheter devices and nozzles disclosed herein. In some embodiments, cryoablation is achieved via the refrigerant property due to the liquid to gas phase change from an ablation medium, such as liquid nitrous oxide, carbon dioxide, and argon. In some embodiments, the phase change of the cryogenic ablation medium is triggered by a sudden reduction in pressure.
In some embodiments, the pressure sensing lumen 1176 can terminate at an orifice O that is disposed in the gallbladder cavity, while the pressure sensor 1115 is located outside of the gallbladder cavity. In other words, the pressure sensing lumen 1176 can fluidically couple an interior of the gallbladder cavity to the pressure sensor 1115. The pressure sensor 1115 can be disposed at the control unit 1110 and/or operatively coupled to the control unit 1110. In such a configuration, the pressure sensor 1115 can measure the pressure inside of the gallbladder cavity while being positioned outside of the gallbladder cavity.
The pressure sensing lumen 1176 can be disposed about the inner shaft 1170 or outer shaft 1160 of the catheter system according to one of several different arrangements. For example, in an embodiment, the pressure sensing lumen 1176 can be affixed to the inner shaft 1170, as shown in
While not expressly identified in
Systems, devices, and methods described herein implement a passive evacuation channel and cryogen control system to safely vent cryogen gas from the gallbladder cavity, while ensuring safe operating conditions. During cryogen delivery, a cryogenic ablation medium (e.g., nitrous oxide) expands and evacuates to an external environment (e.g., atmosphere) through an annular space between an inside surface of the outer shaft 1160 and an outer surface of the inner shaft 1170. Resistance in the evacuation channel can cause the gallbladder cavity to distend, to facilitate exposure of tissue within the lumen to the cryogenic ablation medium. The solenoid valve 1121 can be configured to control or regulate delivery of the ablation medium, e.g., from the ablation medium supply 1120, into the gallbladder lumen. For example, the control unit 1110 can control the solenoid valve 1121 to transition from an open state in which ablation medium can be delivered into the gallbladder lumen to a closed state in which ablation medium can be prevented from being delivered into the gallbladder lumen. While a solenoid valve is provided as the example valve herein, it can be appreciated that other types of valves, including mechanically actuated valves, magnetically actuated valves, etc. can be used to control the delivery of the ablation medium into the gallbladder lumen. The control unit 1110, pressure sensor 1115, and solenoid valve 1121 can produce a closed-loop pressure feedback system for maintaining safe operating pressures within the gallbladder cavity. In particular, in response to detecting a pressure within the gallbladder cavity that is greater than a predetermined maximum threshold, the control unit 1110 can control the solenoid valve 1121 to terminate supply of the ablation medium into the gallbladder cavity and/or evacuate via the outer shaft 1160 the ablation medium from the gallbladder cavity to an external environment. Additionally or alternatively, in response to detecting a pressure within the gallbladder cavity that is less than a predetermined minimum threshold, the control unit 1110 can control the ablation medium supply 1120 and/or solenoid valve 1121 to provide additional ablation medium into the gallbladder cavity to sufficiently distend the gallbladder for cryoablation.
In some embodiments, redundant pressure sensors can help monitor evacuation pressures or detect a problem during cryoablation therapy. A first pressure sensor (e.g., pressure sensor 1215a) can relay intraluminal pressure from the gallbladder, while a second pressure sensor (e.g., pressure sensor 1215b) can relay the pressure from an evacuation channel or lumen in the outer shaft 1260. Based on the readings or measurements of the pressure sensors 1215a, 1215b, the control unit 1210 can monitor and detect errors in device operation and subsequently halt therapy (e.g., terminate delivery of the ablation medium).
For example, when a blockage has occurred in the evacuation channel, the pressure from pressure sensing lumen 1276a can be greater than the pressure from pressure sensing lumen 1276b. This can indicate that cryoablation medium has caused ice to form at a point along the evacuation channel (e.g., at or near a distal end of the shaft 1260), blocking flow through the evacuation channel. In response to detecting this difference in pressure, the control unit 1210 can be configured to halt therapy (e.g., terminate supply of ablation medium into the gallbladder cavity) such that pressure within the gallbladder cavity does not increase without the capability of venting or evacuating that pressure. In some embodiments, the control unit 1210 can further activate one or more heating coils to melt the ice that has caused the blockage to reopen the evacuation channel and allow for evacuation of ablation medium.
In some embodiments, the pressure sensing lumens 1276a, 1276b can be affixed to the inner shaft 1270, as shown in
While not depicted, the control unit 1210 can include the same components as other control units described herein (e.g., control unit 110, 310, 1110), each having substantially the same structure and/or function. For example, control unit 1210 can include a valve (e.g., a solenoid valve) for controlling or regulating delivery of an ablation medium into the gallbladder cavity.
Cryoablation destroys tissue through two mechanisms. First, cryoablation produces low temperatures at the target tissue site that induce intracellular ice crystal formation, and subsequent cell death. Second, cryoablation produces reperfusion damage, which is caused by the activation of cell death signaling cascades in response to surrounding cell apoptosis, which helps reinforce cell lethality and is an important part of a cryoablation procedure.
When looking at tissue destruction as a function of temperature, sensors can be employed to measure the temperature at the cryogen source and/or the temperature gradient throughout the tissue. Both temperature measurements are important to evaluating the tissue and status or effectiveness of the ablation. Therefore, temperature measurement systems that provide information on the thermal gradient within the tissue during the procedure are particularly useful in assessing ablation performance.
In some embodiments, the S-shaped spring-loaded arm of the probe 1580 can be inserted through a delivery lumen (e.g., lumen 262, 264) of the shaft 1560 of the catheter system, in which a maximum radius or lateral extent of the S-shaped spring-loaded arm of the probe 1580 conforms to that of the delivery lumen. When the distal end of the S-shaped spring-loaded arm of the probe 1580 exits the lumen of the shaft 1560, it can transition into an expanded state (e.g., due to spring bias).
In some embodiments, the S-shaped spring-loaded arm 1580 can be made from steel, stainless steel, spring steel, nitinol, a polymer, or a composite with sufficient material elastic and strain bearing properties to enable return to its original confirmation. While the probe 1580 is described as being spring-biased to transition into an expanded structure, it can be appreciated that other mechanisms can be used to bias or extend the distal portion of the probe 1580 toward a tissue surface of the body lumen. For example, a mechanical mechanism (e.g., a pull wire), an electrical mechanism, shape-memory material, etc. can be used to produce a desirable shape and/or expansion of the probe 1580.
The temperature sensor 1586 can be configured to provide temperature data to a processor (e.g., of a control unit, such as control unit 110, 310, etc.) for monitoring and/or analyzing temperature. As described above with reference to
In some embodiments, the temperature sensor 1586 can be configured to penetrate (e.g., pierce) into tissue of the body lumen. For example, the probe 1580 can terminate in a needle or other suitable structure, and the temperature sensor can be mounted to and/or integrated into the needle. The temperature sensor 1586, by being disposed within the tissue, can be configured to obtain temperature measurements of the tissue that are less impacted by the extreme temperature of the ablation medium disposed within the body lumen.
Similar to ablation system 1500, the temperature sensor 1686 can be configured to provide temperature data to a processor (e.g., of a control unit, such as control unit 110, 310, etc.) for monitoring and/or analyzing temperature. As described above with reference to
In some embodiments, the valve geometry can be located on the proximal side of the conforming mating face and leverage the pressure of the cryogen supply line (e.g., pressure within ablation medium delivery lumen, e.g., lumen 272 of an inner shaft 270) to stay in a normally closed state. In some embodiments, a driving force can be applied to break the seal between the valve geometry and the conforming mating face, thereby allowing the flow of cryogen. For example,
In some embodiments, the cryogen supply line volume 1971b (e.g., volume of the ablation medium delivery lumen, e.g., lumen 272 of an inner shaft 270) distal to the valve 1978 is sufficiently small to minimize residual volume pressure buildup, such as that described above with reference to valve 278 depicted in
One of the primary difficulties with consideration to device safety is controlling the intraluminal pressure buildup associated with the phase-change of the liquid nitrous oxide ablation medium sprayed within the gallbladder or other targeted ablation area. More specifically, if a pressure build-up event is detected, there should be a safe way to ensure that the pressure does not continue to build up and is properly evacuated. In the situation where a pressure build up event is occurring, a large concern is the remaining liquid nitrous oxide located within the delivery lumen due to the fact that is has the potential to continue to deliver a large volume of gas, depending on the total volume of the “uncontrolled supply line” or the segment of the supply line that is beyond any mechanical valve, which can cut the flow of the supply line. Accordingly, it can be beneficial to minimize the concern of supply line pressure by monitoring the pressure and adjusting the device accordingly.
According to various embodiments of the present disclosure, a cryoablation device can be configured to control a flow of cryogen within the cryogen delivery lumen a cryoablation device. For example, the cryoablation device can include a valve mechanism or other type of device that can be used to open and/or close an area in the cryogen delivery lumen (e.g., lumen 272 of an inner shaft or ablation catheter 270) thereby restricting or allowing a flow of cryogen past a distal end of the valve mechanism and into a targeted ablation area (e.g., gallbladder). According to various embodiments, the cryoablation device can be in data communication with a computing device that is configured to monitor pressure within a gallbladder lumen or other targeted lumen. As will be discussed below, pressure can be released by controlling cryogen flow via a control valve and/or other component. According to various embodiments, the cryoablation device can comprise one or more pressure sensors in data communication with the computing device. The pressure sensors are configured to measure the pressure within the gallbladder lumen or other targeted lumen.
In some embodiments of the present disclosure, systems, devices, and methods for ablation (e.g., cryoablation) can use or incorporate an ablation feedback or dosage feedback mechanism. The feedback mechanism can be configured to assist in determining when ablation has completed, e.g., when the target tissue has been sufficiently ablated.
The control unit 2210 includes a processor 2212, an input/output interface 2219, a first valve 2221 (supply valve) for controlling delivery of the cryogen supply, and a second valve 2222 (purge valve) for controlling purging of the ablation delivery line. In some embodiments, an expandable structure 2279 can hold or maintain the outer shaft 2260 in the gallbladder cavity, e.g., during an ablation procedure. The processor 2212 is operatively coupled to the first and second valves 2221, 2222. The control unit 2210 can control the opening and closing of the first and second vales 2221, 2222. Stated differently, the control unit 2210 can be configured to cause the valves 2221, 2222 to transition between an open configuration and a closed configuration. In an embodiment, the valves 2221, 2222 can be solenoid valves.
Ablation medium can flow from the ablation medium supply 2220 into the inner shaft 2270, passing by the valve 2221. The valve 2221 can be configured to open (e.g., be set to the open configuration) to allow delivery of cryogenic ablation medium into the gallbladder cavity. Additionally, the valve 2221 can be configured to close (e.g., be set to the closed configuration) to shut off delivery of cryogenic ablation medium into the gallbladder cavity, e.g., to prevent over-pressuring the gallbladder cavity and/or after receiving feedback indicating that the ablation is complete. In some embodiments, after the valve 2221 is closed, the valve 2222 can open (e.g., be set to the open configuration) to control purging of the ablation medium line, e.g., purging of excess ablation medium within the fluid delivery path between the valve 2221 and the nozzle or openings of the inner shaft or cryogen delivery catheter 2270. The valve 2222 can be configured to open a channel or pathway to an exterior of the cryoablation device 2200, via which excess ablation medium can be vented or purged. While not depicted, in some embodiments, the cryoablation device 2200 can include one or more pressure sensing lumens or pressure sensors, e.g., as described with reference to
Similar to other embodiments described herein, cryoablation gas delivered into the gallbladder lumen can exit the lumen via the outer shaft 2260 or, specifically, an annular space between the inner and outer shafts. In some embodiments, one or more temperature sensors 2216 can be placed at various locations along a flow path of gas that exits the gallbladder cavity through the outer shaft 2260. As shown, the cryoablation device 2200 includes a first temperature sensor 2216a and a second temperature sensor 2216b (collectively referred to as temperature sensors 2216). The first temperature sensor 2216 can be positioned within the gallbladder lumen and be configured to measure a temperature of the cryoablation gas within the gallbladder cavity, e.g., at a point where the gas exits into the outer shaft 2260. The second temperature sensor 2216b can configured to measure the temperature of the cryoablation gas as it leaves the outer shaft 2260.
In some embodiments, one or more of the temperature sensors 2216 can be coupled to an exterior side of the inner shaft 2270. In some embodiments, one or more of the temperature sensors 2216 can be coupled to an interior side of the outer shaft 2260. In some embodiments, the first and second temperature sensors 2216a, 2216b can be positioned along a length of the inner shaft or cryoablation delivery catheter 2270. For example, the first and second temperature sensors 2216a, 2216b can be coupled to the inner shaft 2270 at different locations along its length. Alternatively, in some embodiments, one or both of the first and second temperature sensors 2216a, 2216b can be coupled to the outer shaft or introducer sheath 2260. Still alternatively, in some embodiments, the second temperature sensor 2216b can be positioned at a more proximal location along the evacuation path of the cryogenic ablation medium, e.g., in the purge valve 2222 or in close proximity to the purge valve 2222 such that the second temperature sensor 2216b can measure the temperature of the gas as the gas moves through the purge valve 2222.
Measuring the exhaust gas temperature via the temperature sensors 2216 can have several advantages. First, these sensors 2216 can provide real-time feedback of the average temperature in the body lumen. The temperature data can be analyzed, e.g., by the control unit 2210 (or specifically, by the processor 2212 of the control unit 2210) to determine whether a sufficient dosage of ablation medium has been delivered to the lumen to ablate the target tissue. The more contact the temperature sensors 2216 have with the exhaust gas, the more accurate and responsive their readings are. In general, more temperature sensors can provide a more accurate characterization of the exhaust gas. As shown, the cryoablation device 2200 includes two temperature sensors 2216. In some embodiments, the cryoablation device 2200 can include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or at least about 10 temperature sensors 2216, inclusive of all values and ranges therebetween. Each of the temperature sensors can be disposed at a location along the evacuation path of the cryoablation gas. In some embodiments, the temperature sensors 2216 can include T-type thermocouples.
In some embodiments, one or more of the temperature sensors 2216 can be positioned at a location distal to the distal end of the outer shaft 2260. In some embodiments, one or more of the temperature sensors 2216 can be positioned about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 350 μm, about 400 μm, about 450 μm, about 500 μm, about 550 μm, about 600 μm, about 650 μm, about 700 μm, about 750 μm, about 800 μm, about 850 μm, about 900 μm, about 950 μm, about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, or about 10 cm distal to the distal end of the outer shaft 2260, inclusive of all values and ranges therebetween.
In some embodiments, one or more of the temperature sensors 2216 can be positioned at a location proximal to the proximal end of the outer shaft 2260. In some embodiments, one or more of the temperature sensors 2216 can be positioned about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 350 μm, about 400 μm, about 450 μm, about 500 μm, about 550 μm, about 600 μm, about 650 μm, about 700 μm, about 750 μm, about 800 μm, about 850 μm, about 900 μm, about 950 μm, about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, or about 10 cm proximal to the proximal end of the outer shaft 2260, inclusive of all values and ranges therebetween.
The control unit 2310 includes a processor 2312, an input/output interface 2319, a supply valve 2321, and a purge valve 2322. The processor 2312, input/output interface 2319, supply valve 2321, and purge valve 2322 can be structurally and/or functionally similar to the processor 2212, input/output interface 2219, supply valve 2221, and purge valve 2222 described with reference to
As shown, the cryoablation device 2300 includes a first temperature sensor 2316a and a second temperature sensor 2316b (collectively referred to as temperature sensors 2316). The first and second temperature sensors 2316a, 2316b can be structurally and/or functionally similar to the first and second temperature sensors 2216a, 2216b but be disposed on or coupled to the outer shaft 2360 instead of the inner shaft 2370. In particular, the first temperature sensor 2316a is coupled to the interior of the outer shaft 2360 in the gallbladder cavity and the second temperature sensor 2316b is coupled to the interior of the outer shaft 2360 at the proximal end of the outer shaft 2360.
For cryoablation device, it can be beneficial to monitor the temperature of gases exiting the gallbladder lumen, e.g., for safety reasons and/or for assessing the progress or status of ablation (e.g., assessing when ablation is complete).
Different tissue targets or body lumens can be associated with different thermal loads, e.g., depending on their characteristics. Body lumens with high thermal loads may be large, have thickened walls, and/or have a high level of vascularization. The higher the thermal load of the body lumen, the more energy may be necessary to cool the lumen. In other words, given an equal amount of time, higher thermal load targets would reach a temperature that is greater than the temperature of lower thermal load targets. Therefore, each body lumen may have different exhaust gas cooling rates and therefore require different amounts of time to sufficiently ablate.
Monitoring the exhaust gas temperatures can provide an indication of when the body lumen has cooled sufficiently and therefore has been sufficiently ablated. This in turn can help provide an approximation of an amount of time the ablation systems described herein would need to deliver cryoablation into the gallbladder lumen. Additionally, the phase-change diagram of N2O, as depicted in
In some embodiments, the target time period for the exhaust gas temperature to be at or below the desired value at step 2602 can be at least about 1 s, at least about 2 s, at least about 3 s, at least about 4 s, at least about 5 s, at least about 10 s, at least about 15 s, at least about 20 s, at least about 25 s, at least about 30 s, or at least about 1 minute. In some embodiments, the target time period for the exhaust gas temperature to be at or below the desired value at step 2602 can be no more than about 1 minute, no more than about 30 s, no more than about 25 s, no more than about 20 s, no more than about 15 s, no more than about 10 s, no more than about 5 s, no more than about 4 s, no more than about 3 s, no more than about 2 s, or no more than about 1 s. Combinations of the above-referenced time periods are also possible.
In some embodiments, system, devices, and methods described herein can rely on feedback pressure. For example, as described with reference to
In some embodiments, the cryoablation device can also include a temperature sensors (e.g., temperature sensors 2216a, 2216b, 2316a, 2316b) that are configured to measure a temperature of gases exiting the gallbladder lumen. As such, both temperature and pressure data can be used to provide feedback to a control unit (e.g., a processor of any of the control units described herein) to monitor ablation and determine dosage.
The cryoablation catheter 2970 can include a nozzle or a plurality of openings or fenestrations, similar to other cryoablation catheters described herein. The nozzle can be configured to delivery a cryogenic ablation medium into a body lumen, such as, for example, a gallbladder lumen. The cryoablation catheter 2970 can also include a cage or other expandable body, which can be configured to expand to space the nozzle from a wall of the body lumen, e.g., to facilitate the distribution of cryogenic ablation medium.
The cryoablation catheter 2970 can include a portion that can be disposed internally within a patient. For example, the nozzle and cage of the cryoablation catheter 2970 can be disposed within a gallbladder lumen. While the cryoablation catheter 2970 is described as a catheter, it can be appreciated that the cryoablation catheter 2970 can be configured as a shaft, which can be disposed within an outer shaft or access sheath, similar to that described with reference to
The cryogen source 2920 can be configured to deliver a cryogenic ablation medium to the cryoablation catheter 2970. In some embodiments, the cryogen source 2920 can be a tank or cartridge that includes a liquid cryogenic ablation medium (e.g., nitrous oxide), which can be delivered via a high-pressure delivery line 2922 to the cryoablation catheter 2970. The cryoablation catheter 2970 can include or be coupled to a handle interface 2902, e.g., for receiving the cryogenic ablation medium from the high-pressure delivery line 2922.
The ablation system also includes a controller implemented as a heater controller 2910, a delivery line heater 2930, and a heater thermocouple 2932. The heater controller 2910 can be structurally and/or functionally similar to other control units or controllers described herein (e.g., control unit 110). In some embodiments, the heater controller 2910 can be a closed-loop controller for controlling the operation of the heater 2930. In some embodiments, the controller 2910 can be a proportional-integral-derivative (PID) controller, which employs feedback to control the heater 2930. The controller 2910 can use the thermocouple 2932 to achieve a set point temperature (At) between a room temperature and a critical temperature of the cryogenic ablation medium (e.g., between about 20° C. and about 37° C., including all sub-ranges and values therebetween). The thermocouple 2932 can be configured to provide temperature feedback for the closed-loop controller 2910. In some embodiments, the thermocouple 2932 can be embedded near the heater 2930 (e.g., near the coils of the resistive wire). The critical temperature of the cryogenic ablation medium represents the temperature at which a cryogenic ablation medium is 100% is gaseous phase and therefore has little or no refrigeration potential. In an embodiment, the cryogenic ablation medium can be nitrous oxide with a critical temperature of about 36.5° C., and the controller 2910 can be configured to achieve a set point temperature that is between room temperature and 36.5° C.
The heater 2910 can be configured to be located along the delivery line 2922. The heater 2910 can be configured to transfer heat to the cryogenic ablation medium being delivered through the delivery line 2922, e.g., to reduce a refrigeration power of the cryogenic ablation medium. In some embodiments, the heater 2910 can include a resistive heating coil wrapped around the delivery line 2922 (e.g., a resistive heating wire wrapped around a polyetheretherketone (PEEK) delivery line 2922). Alternatively, the heater 2910 can be any other type of conductive heating (e.g., heated fluid water jacket, inductively heated metal flow path, thermoelectric heating element). The delivery line 2922 (and thermal contact with the heater 2930) can be formed of a heat conductive material, e.g., to facilitate heat transfer from the heater 2930 to the cryogenic ablation medium disposed within the line 2922. The rate of heat transfer to the cryogenic ablation medium can be dependent on a number of factors, including, for example, heater length or length of delivery line being heated (x), power density (W/m), and the set point temperature (Δt).
The modulation of the power input to the heater 2930 (or control of other parameters that may affect the rate of heat transfer) can lead to modulation of the refrigeration potential or power of the cryogenic ablation medium, which can be useful in throttling cooling power during an ablation procedure.
While
As described above with reference to
While the cryogenic ablation medium is being delivered, the ablation system can also monitor the exhaust gas temperature to determine whether to activate a delivery line heater (e.g., delivery line heater 230, 2930, etc.). In some embodiments, the ablation system can also include one or more pressure sensors, e.g., for checking a pressure of the body lumen, at 3308. When the pressure is within a safe range (e.g., within a predefined range of pressure values), then the system can continue delivering the cryogenic ablation medium. When the pressure is outside of the safe range, then the system can stop the delivery of the ablation medium.
It will be appreciated that the present disclosure may include any one and up to all of the following examples.
Example 1: A cryoablation catheter, comprising: a catheter body comprising a cryogen delivery lumen for delivery of a cryogen to an area of tissue; and a valve mechanism disposed at a distal end section of the cryogen delivery lumen, the valve mechanism being configured to control a flow of the cryogen.
Example 2: The cryoablation catheter of example 1, wherein the cryogen comprises nitrous oxide.
Example 3: The cryoablation catheter of example 1, further comprising a nozzle positioned at a distal end of the cryogen delivery lumen, the nozzle being configured to uniformly disperse the cryogen onto the area of tissue when the valve mechanism is in an open configuration that allows the cryogen to flow out of the distal end the cryogen delivery lumen and into the nozzle.
Example 4: The cryoablation catheter of example 1, wherein the valve mechanism is configured to: impede the flow of the cryogen to prevent the cryogen from exiting a distal end of at least one cryogen delivery lumen and being dispersed onto the area of tissue when in a closed configuration; and allow the cryogen to flow through the distal end of the cryogen delivery lumen and be dispersed onto the area of tissue when in an open configuration.
Example 5: The cryoablation catheter of example 1, wherein the valve mechanism comprises a valve component that is sized and shaped to engage with a conforming mating face of the cryogen delivery lumen thereby causing a seal.
Example 6: The cryoablation catheter of example 5, wherein the valve mechanism further comprises a driving mechanism coupled to the valve component, and the driving mechanism is configured to generate an opposing force against the valve component to cause movement of the valve component relative to the conforming mating face of the cryogen delivery lumen.
Example 7: The cryoablation catheter of example 6, wherein the driving mechanism comprises at least one of: a drive wire, a drive rod, pneumatic pressure system, hydraulic pressure system, an electromagnetic force system, or a motor.
Example 8: The cryoablation catheter of any one of examples 5 or 6, wherein the valve mechanism further comprises a positioning component coupled to the valve component, and the positioning component is configured to position the valve component against the mating face of the cryogen delivery lumen such that a normal configuration of the valve mechanism is in a closed configuration to impede a flow of cryogen.
Example 9: The cryoablation catheter of example 8, wherein the positioning component comprises a spring return mechanism or a cable tension system.
Example 10: The cryoablation catheter of any one of examples 5-9, wherein the valve component is positioned on a proximal side of a mating face of the cryogen delivery lumen.
Example 11: The cryoablation catheter of example 10, wherein a pressure associated with the cryogen causes the valve component to rest against the proximal side of the mating face of the cryogen delivery lumen.
Example 12: The cryoablation catheter of any one of examples 5-11, wherein the conforming mating face of the cryogen delivery lumen is positioned between a first portion of the cryogen delivery lumen and a second segment of the cryogen delivery lumen, the second segment being distal to the mating face.
Example 13: The cryoablation catheter of example 12, wherein a volume of the second segment of the cryogen delivery lumen is sized to minimize residual volume pressure buildup associated with the cryogen.
Example 14: The cryoablation catheter of example 13, wherein a length of the second segment is about 0-10 centimeters.
Example 15: A method, comprising: dispersing, via a catheter of a cryoablation device, cryogen onto an area of tissue in a body lumen, the cryogen being delivered via a delivery lumen of the catheter; measuring, via a pressure sensor disposed within the body lumen, a pressure within the body lumen; determining, via a computing device, whether the pressure exceeds a predefined threshold; and reducing the pressure in the body lumen in response to determining that the pressure exceeds the predefined threshold.
Example 16: A system, comprising: a cryoablation catheter configured to uniformly disperse cryogen to an area of tissue in a lumen; a pressure sensor disposed within the cryoablation catheter, the pressure sensor being configured to measure a pressure within the lumen; and a processor in data communication with the pressure sensor, the processor being configured to: obtain pressure data from the pressure sensor; determine whether the pressure associated with lumen is within a predefined pressure threshold; and initiate a reduction of pressure within the lumen in response to determining that the pressure is outside the predefined pressure threshold.
It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.
Also, various concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.
As used herein, the terms “about” and/or “approximately” when used in conjunction with numerical values and/or ranges generally refer to those numerical values and/or ranges near to a recited numerical value and/or range. In some instances, the terms “about” and “approximately” may mean within ±10% of the recited value. For example, in some instances, “about 100 [units]” may mean within ±10% of 100 (e.g., from 90 to 110). The terms “about” and “approximately” may be used interchangeably.
Some embodiments described herein relate to a computer storage product with a non-transitory computer-readable medium (also may be referred to as a non-transitory processor-readable medium) having instructions or computer code thereon for performing various computer-implemented operations. The computer-readable medium (or processor-readable medium) is non-transitory in the sense that it does not include transitory propagating signals per se (e.g., a propagating electromagnetic wave carrying information on a transmission medium such as space or a cable). The media and computer code (also may be referred to as code or algorithm) may be those designed and constructed for the specific purpose or purposes. Examples of non-transitory computer-readable media include, but are not limited to, magnetic storage media such as hard disks, floppy disks, and magnetic tape; optical storage media such as Compact Disc/Digital Video Discs (CD/DVDs), Compact Disc-Read Only Memories (CD-ROMs), and holographic devices; magneto-optical storage media such as optical disks; carrier wave signal processing modules; and hardware devices that are specially configured to store and execute program code, such as Application-Specific Integrated Circuits (ASICs), Programmable Logic Devices (PLDs), Read-Only Memory (ROM) and Random-Access Memory (RAM) devices. Other embodiments described herein relate to a computer program product, which may include, for example, the instructions and/or computer code disclosed herein.
The systems, devices, and/or methods described herein may be performed by software (executed on hardware), hardware, or a combination thereof. Hardware modules may include, for example, a general-purpose processor (or microprocessor or microcontroller), a field programmable gate array (FPGA), and/or an application specific integrated circuit (ASIC). Software modules (executed on hardware) may be expressed in a variety of software languages (e.g., computer code), including C, C++, Java®, Ruby, Visual Basic®, and/or other object-oriented, procedural, or other programming language and development tools. Examples of computer code include, but are not limited to, micro-code or micro-instructions, machine instructions, such as produced by a compiler, code used to produce a web service, and files containing higher-level instructions that are executed by a computer using an interpreter. Additional examples of computer code include, but are not limited to, control signals, encrypted code, and compressed code.
This application is a continuation of International Patent Application No. PCT/US2023/062419, entitled “SYSTEMS, DEVICES, AND METHODS FOR ABLATION AND DEFUNCTIONALIZATION OF A GALLBLADDER WITH DOSAGE FEEDBACK,” filed Feb. 10, 2023 which claims the priority to and the benefit of U.S. Provisional Application No. 63/308,548, entitled “SYSTEMS, DEVICES, AND METHODS FOR ABLATION AND DEFUNCTIONALIZATION OF A GALLBLADDER WITH DOSAGE FEEDBACK,” filed on Feb. 10, 2022, the disclosures of which are hereby incorporated by reference in their entirety.
This invention was made with government support under Grant No. 1938608 of the National Science Foundation Small Business Innovation Research (SBIR)/Small Business Technology Transfer (STTR) Phase I.
| Number | Date | Country | |
|---|---|---|---|
| 63308548 | Feb 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2023/062419 | Feb 2023 | WO |
| Child | 18798810 | US |
