Delivery system for cryoablation device

Abstract

One embodiment includes a cryoablation shaft. The cryoablation shaft includes a working fluid circuit, a vacuum circuit, an insulating portion in which the vacuum circuit extends within the insulating portion, an expansion chamber, a supply pipe having a distal outlet within the expansion chamber, through which fluid from the working fluid circuit moves distally down the cryoablation shaft and expands in the expansion chamber, and a guidewire lumen. The guidewire lumen includes a metal tube and a polymer sleeve configured to surround at least a portion of the metal tube.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a cryoablation system, and more particularly, to a delivery device for a cryoablation system. This application claims priority to U.S. Provisional Patent Application No. 63 / 468,968, filed May 25, 2023, and U.S. Patent Application No. 18 / 671,727, filed May 22, 2024, the contents of which are hereby incorporated by reference in their entirety.

Background Art

[0002] During cryosurgery, a surgeon may place one or more cryoprobes to freeze and thaw tissue to excise a target region of a patient's anatomical structure. In one example, a cryoprobe uses the Joule-Thomson effect to effect cooling or heating of the probe tip. In such cases, a cryogenic fluid within the cryoablation probe expands from high pressure to low pressure, causing the device tip to cool to a temperature corresponding to or lower than the cryoablation of the tissue in the vicinity of the tip. Heat transfer between the expanded cryogenic fluid and the outer wall of the cryoprobe forms an ice ball in the tissue surrounding the tip, followed by cryoablation of the tissue.

Summary of the Invention

[0003] In a first embodiment, the cryoablation shaft includes a working fluid circuit, a vacuum circuit, an insulating portion wherein the vacuum circuit extends into the insulating portion, and an expansion chamber extending distal to the insulating portion. The cryoablation shaft further includes a guidewire lumen configured for guidewire insertion and extending along the length of the cryoablation shaft. The guidewire lumen may include a metal tube and a polymer sleeve configured to surround at least a portion of the metal tube. The cryoablation shaft further includes a supply tube having a distal outlet in the expansion chamber, through which a fluid from the working fluid circuit travels distally down the cryoablation shaft and expands in the expansion chamber, a return tube surrounding the supply tube, and an insulating shaft surrounding the return tube.

[0004] In a second embodiment, in addition to or instead of one or more of the embodiments described above, the guide wire lumen may be coaxially located within the supply pipe, the supply pipe may be coaxially located within the return pipe, and at least a portion of the return pipe may be coaxially located within the adiabatic shaft.

[0005] In a third embodiment, in addition to or in lieu of one or more of the embodiments described above or below, the fluid from the working fluid circuit moves distally down the cryoablation shaft through an annular space defined between the return pipe and the guidewire lumen.

[0006] In the fourth embodiment, in addition to or instead of one or more of the embodiments described above or below, the metal tube may include either nitinol or stainless steel. In the fifth embodiment, in addition to or instead of one or more of the embodiments described above or below, the polymer sleeve may include either a polyether block amide or polyethylene terephthalate.

[0007] In a sixth embodiment, in addition to or instead of one or more of the embodiments described above, at least a portion of the metal tube may include a plurality of slots, and the polymer sleeve may be configured to form a seal around the portion of the metal tube including the plurality of slots.

[0008] In the seventh embodiment, in addition to or in place of one or more of the embodiments described above or below, the cryoablation shaft further includes a distal tip portion containing metal, which is configured to seal the distal end of the expansion chamber at the distal tip portion of the cryoablation shaft.

[0009] In the eighth aspect, in addition to or instead of one or more of the preceding or following aspects, the distal end of the metal tube may be joined to the proximal end of the distal tip using an intermetallic joining process.

[0010] In the ninth embodiment, in addition to or instead of one or more of the embodiments described above, the distal tip may define a central channel, the central channel may be configured to receive the guidewire. The proximal end of the central channel of the distal tip may be joined to the distal end of the metal tube.

[0011] In a tenth embodiment, in addition to or instead of one or more of the embodiments described above or below, the cryoablation shaft may include a first compression winding portion configured to seal the polymer sleeve to the metal tube at the distal end of the polymer sleeve.

[0012] In an eleventh embodiment, in addition to or instead of one or more of the embodiments described above, the cryoablation shaft may include a second compression winding portion configured to seal the polymer sleeve to the metal tube at the proximal end of the polymer sleeve.

[0013] In the twelfth embodiment, in addition to or instead of one or more of the embodiments described above or below, the guide wire lumen is capable of forming a curve having a minimum radius of curvature of 30 mm or less.

[0014] In a thirteenth embodiment, the guidewire lumen of a cryoablation shaft may include a metal tube, the metal tube having at least a portion thereof comprising a plurality of slots; a polymer sleeve configured to form a seal around the portion of the metal tube comprising the plurality of slots; and a distal tip. The guidewire lumen is configured for guidewire insertion and may extend over the length of the cryoablation shaft. The metal tube may be configured to be joined to the distal tip at the distal end of the cryoablation shaft using an intermetallic bonding process.

[0015] In the fourteenth embodiment, in addition to or instead of one or more of the embodiments described above or below, the guide wire lumen may be coaxially located in the supply pipe of the cryoablation shaft, the supply pipe may be coaxially located in the return pipe of the cryoablation shaft, and at least a portion of the return pipe may be coaxially located in the adiabatic shaft of the cryoablation shaft.

[0016] In the 15th embodiment, in addition to or instead of one or more of the embodiments described above or below, the metal tube may include either nitinol or stainless steel. In the sixteenth embodiment, in addition to or instead of one or more of the embodiments described above or below, the polymer sleeve may include either a polyether block amide or polyethylene terephthalate.

[0017] In a 17th embodiment, in addition to or instead of one or more of the embodiments described above or below, the guidewire lumen may further include a compression winding portion configured to seal the polymer sleeve to the metal tube.

[0018] In the 18th embodiment, in addition to or instead of one or more of the embodiments described above or below, the guide wire lumen is capable of forming a curve having a minimum radius of curvature of 30 mm or less.

[0019] In a 19th embodiment, the cryoablation shaft may include a working fluid circuit, a vacuum circuit, an insulating portion in which the vacuum circuit extends within the insulating portion, an expansion chamber, and a guidewire lumen configured for guidewire insertion and extending over the length of the cryoablation shaft. The guidewire lumen may include a metal tube in which at least a portion of the metal tube includes a plurality of slots, and a polymer sleeve surrounding at least a portion of the metal tube and configured to form a seal around the portion of the metal tube including the plurality of slots. The cryoablation shaft may further include a supply tube having a distal outlet in the expansion chamber, through which a fluid from the working fluid circuit travels distally down the cryoablation shaft and expands in the expansion chamber, a return tube surrounding the supply tube, and an insulating shaft surrounding the return tube. The guidewire lumen may be coaxially located within the supply tube. The supply tube may be coaxially located within the return tube. The return pipe may be located coaxially within the insulated shaft.

[0020] In a 20th embodiment, in addition to or in place of one or more of the embodiments described above or below, the cryoablation shaft may further include a distal tip portion containing metal, which is configured to seal the distal end of the expansion chamber at the distal tip of the cryoablation shaft.

[0021] This summary is some of the teachings of this application and is not intended to be an exclusive or comprehensive treatment of the subject matter. Further details are found in the detailed description and the appended claims. Each aspect can be more fully understood by being associated with the figures. Other aspects may become apparent to those skilled in the art by reading the following detailed description and viewing the drawings that form a part thereof, but each aspect should not be construed in a limiting sense. The scope of the present disclosure is defined by the appended claims and their legal equivalents.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1 is a schematic view of a cryoablation system according to various embodiments of the present disclosure. [Figure 2] FIG. 2 is a schematic view of a part of a cryoablation system according to various embodiments of the present disclosure. [Figure 3] FIG. 3 is a schematic view of a part of a cryoablation shaft shown according to various embodiments of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view of the shaft of FIG. 3 taken along section 4-4 according to various embodiments of the present disclosure. [Figure 5] FIG. 5 is a cross-sectional view of the shaft of FIG. 3 taken along section 5-5 according to various embodiments of the present disclosure. [Figure 6] FIG. 6 is a schematic view of the biliary system according to various embodiments of the present disclosure. [Figure 7] FIG. 7 is a schematic view of the growth of an ice ball generated by a cryoablation system according to various embodiments of the present disclosure. [Figure 8] FIG. 8 is a schematic view of a part of a cryoablation shaft according to various embodiments of the present disclosure. [Figure 9] FIG. 9 is a schematic view of a part of a cryoablation shaft according to various embodiments of the present disclosure. [Figure 10]FIG. 10 is a schematic view of a portion of a cryoablation shaft according to various embodiments of the present disclosure. [Figure 11] FIG. 11 is a radial cross-sectional view of a cryoablation shaft according to various embodiments of the present disclosure. [Figure 12] FIG. 12 is a radial cross-sectional view of a cryoablation shaft according to various embodiments of the present disclosure. [Figure 13] FIG. 13 is a radial cross-sectional view of a cryoablation shaft according to various embodiments of the present disclosure. [Figure 14] FIG. 14 is a cross-sectional view of a guide wire lumen and distal tip according to various embodiments of the present disclosure. [Figure 15] FIG. 15 is a cross-sectional view of a cryoablation shaft including the guide wire lumen and distal tip of FIG. 14 according to various embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] While each embodiment may take various changes and alternative forms, details of each embodiment are shown by way of example in the drawings and will be described in detail below. The scope of the present disclosure is not limited to the specific aspects described. Rather, it is intended to encompass modifications, equivalents, and alternatives included within the spirit and scope of the present disclosure.

[0024] Some cryoablation systems may be useful for ablating lesions in the biliary tract or other difficult-to-access parts of the human anatomy. In such cases, the cryoprobe may need to travel through a tortuous passage. A cryoprobe with a rigid shaft may not be suitable for such applications.

[0025] The present disclosure relates to a cryoablation system having a flexible shaft. This shaft may have sufficient flexibility to access specific parts of the human anatomy, such as the biliary tract, while maintaining appropriate burst strength and thermal insulation to ensure patient safety.

[0026] In various embodiments, the cryoablation system preferably includes a guidewire. A guidewire, as defined herein, is a flexible medical wire inserted into the body to guide a larger instrument, such as a catheter, to a target location. Including a guidewire in the cryoablation system allows for access to parts of the patient's anatomical structure (e.g., the biliary system) with greater precision and less damage to the flexible shaft. The guidewire may extend within a guidewire lumen that extends over part or all of the length of the shaft. The guidewire may be added to the cryoablation system in either a monorail configuration or an over-the-wire configuration. In alternative embodiments, the cryoablation system may be introduced into the patient using a sheath instead of a guidewire. Advantageous guidewire lumen configurations are described herein.

[0027] The concepts described herein may be applied in connection with the cryoablation systems described in U.S. Patent Application Publication No. 2021 / 00045793, entitled "Dual Stage Cryocooler," and U.S. Patent Application Publication No. 2021 / 00045794, entitled "Flexible Cryoprobe," both filed on August 14, 2020, both of which are incorporated herein by reference in their entirety.

[0028] Referring to Figure 1, schematic diagrams of cryoablation systems according to various embodiments of the present disclosure are shown. In various embodiments, the cryoablation system may include a handle 102 and a shaft 104. In various embodiments, the shaft 104 is insertable into the handle 102 and can be securely attached to the handle using a shaft-to-handle connector 103. In various embodiments, the shaft 104 and the shaft-to-handle connector 103 of the cryoablation system 100 may form a catheter assembly. In some embodiments, the catheter assembly includes components of the cryoablation system that are replaced each time a cryoablation procedure is performed. In some aspects, the cryoablation system 100 may include a working fluid source 110, a pre-cooler fluid source 112, and a vacuum source 114, each connectable to the cryoablation system 100.

[0029] These three sources correspond to three independent circuits within the refrigeration ablation system 100: namely, the precooler, the working fluid, and the active vacuum. In some embodiments, the working fluid source 110 and the precooler fluid source 112 are connected to the base of the handle 102 of the refrigeration ablation system 100, and the vacuum source 114 is connected near the distal end of the handle, adjacent to the shaft-to-handle connector 103. The refrigeration ablation system may further include a precooler gas exhaust port 116 and a working gas exhaust port 118 connected to the handle 102. In various embodiments, the shaft-to-handle connector 103 functions as a manifold, maintaining each fluid circuit isolated from one another.

[0030] In some embodiments, the cryoablation system 100 includes a console 117. The console may be used to control the system. The console may be electrically connected to the handle and the cryoablation assembly, and may also be in fluid communication. In some embodiments, the working fluid source 110, the precooler fluid source 112, and the vacuum source 114 may all be connectable to the console 117 of the cryoablation system 100 using conduits. In some embodiments, the precooler gas exhaust port 116, the working gas exhaust port 118, or both may be connectable to conduits that return the exhaust to the console 117 or another location in the treatment room, so that the exhaust is released into the ambient environment at an appropriate location. Various supply and exhaust ports may be arranged in any suitable configuration at predetermined locations along the handle 102. Thus, the arrangement in Figure 1 is only one example of a suitable configuration.

[0031] Examples of the specifications and functions of each of these circuits are provided in the following paragraphs. However, the specific fluid and pressure values ​​are for illustrative purposes only, and other configurations are possible. In one embodiment, the pre-cooler circuit may include pressurized argon at 24.1 megapascals (MPa). The pre-cooler circuit can cool the incoming working fluid and operate within the handle. In one embodiment, the working fluid circuit may include pressurized argon at 12.4 MPa and / or pressurized helium at 12.4 MPa. The working fluid circuit generates and / or thaws an ice ball. The working fluid circuit can operate within the handle, within the insulated portion or region of the shaft, and within the expansion chamber of the shaft. In one embodiment, the active vacuum can maintain a vacuum of 6.67 pascals (Pa) or less. The active vacuum can insulate the shaft. The active vacuum can operate within the handle and within the insulated region of the shaft.

[0032] In various embodiments, the working fluid circuit extends inside both the handle 102 and the shaft 104 of the cryoablation system 100 and carries the fluid that generates and thaws the ice ball. The term “fluid circuit” as used throughout this application may be replaced in various embodiments with a gas circuit, a liquid circuit, a fluid chamber, a gas chamber, or a liquid chamber. Also, the term “fluid” as used throughout this application may be replaced in various embodiments with a gas or a liquid. During ablation (freezing cycle), argon at 12.4 MPa is circulated through the probe to generate an ice ball inside the patient’s body surrounding the expansion chamber 106. The working fluid can be any suitable cooling fluid (e.g., nitrogen, air, argon, krypton, xenon, N2O, CO2, CF4). In some embodiments, the pressure of the high-pressure flow of the working fluid may be 6.9 MPa, 8.3 MPa, 9.7 MPa, 11.0 MPa, 12.4 MPa, 17.2 MPa, 27.6 MPa, or 41.4 MPa or higher. In some embodiments, the pressure of the working fluid high-pressure flow may be 55.2 MPa, 34.5 MPa, 20.7 MPa, 18.6 MPa, 16.5 MPa, 14.5 MPa, or 12.4 MPa or less. In some embodiments, the pressure of the working fluid high-pressure flow may be in the range of 6.9 MPa to 41.4 MPa, 8.3 MPa to 27.6 MPa, 9.7 MPa to 16.5 MPa, 11.0 MPa to 14.5 MPa, or about 12.4 MPa. Therefore, in embodiments where the working fluid is a cooling fluid, the temperature of the working fluid in the expansion chamber 106 may be about 190 Kelvin. In some embodiments, the temperature of the working fluid may be 250 Kelvin, 200 Kelvin, 150 Kelvin, or 100 Kelvin or less, or within a range of any of these.

[0033] In various embodiments, the pre-cooler circuit is completely housed within the handle 102. In various embodiments, the pre-cooler circuit is located within the system console 117. In various embodiments, the pre-cooler circuit is located within a portion of the catheter located immediately proximal to the handle. In various embodiments, the pre-cooler circuit is located within a portion of the catheter located immediately distal to the handle. In various embodiments, the pre-cooler circuit operates using argon or any other suitable cooling fluid. In some embodiments, the high-pressure flow of the pre-cooler fluid may be at a higher pressure than the high-pressure flow of the working fluid. The pre-cooler fluid may be supplied at a pressure higher than, for example, about 13.8 MPa. In some embodiments, the pressure of the pre-cooler fluid may be 10.3 MPa, 13.8 MPa, 17.2 MPa, 20.7 MPa, or 24.1 MPa or higher. In some embodiments, the pressure of the pre-cooler fluid may be 31.0 MPa, 29.3 MPa, 25.9 MPa, or 24.1 MPa or lower. In some embodiments, the pressure of the precooler fluid may be in the range of 10.3 MPa to 31.0 MPa, 13.8 MPa to 29.3 MPa, 17.2 MPa to 27.6 MPa, 20.7 MPa to 25.9 MPa, or about 24.1 MPa.

[0034] In some embodiments, the outer surface of the shaft 104 can be insulated from the inner surface of the shaft. In various embodiments, a vacuum circuit or vacuum chamber extends both within the handle 102 and within the insulated region 105 of the shaft 104. Throughout the cryoablation procedure, a vacuum is actively drawn along the insulated region 105 of the shaft 104, providing a protective barrier between the outer surface of the shaft 104 and the patient. In alternative embodiments, shaft insulation can be achieved by circulating a fluid, gas, or heating fluid throughout the shaft, or by electrically heating a portion of the shaft. In alternative embodiments, shaft insulation can be achieved by housing a non-circulating fluid or gas within the insulated shaft.

[0035] The shaft 104 may be any appropriate length that allows it to reach the target anatomical structure of the subject. In some embodiments, the shaft length may be 20 cm, 38 cm, 55 cm, 72 cm, or 90 cm or more. In some embodiments, the shaft length may be 150 cm, 135 cm, 120 cm, 105 cm, or 90 cm or less. In some embodiments, the shaft length may be in the range of 20 cm to 150 cm, 38 cm to 135 cm, 55 cm to 120 cm, 72 cm to 105 cm, or about 90 cm.

[0036] In various embodiments, specific portions of the shaft 104 may be flexible. In one embodiment, the entire length of the shaft may be flexible. For example, the shaft may be bendable about its longitudinal axis. In some such embodiments, the shaft may have a shaft diameter configured such that the shaft is flexible enough to form a curve with a desired radius of curvature. For example, the shaft may be flexible enough to form a curve with a minimum radius of curvature of 30 mm, 20 mm, 10 mm, or 5 mm or less.

[0037] In various embodiments, the shaft 104 may include an insulated region 105 and an expansion chamber 106. The insulated region 105 defines the portion of the shaft 104 that is insulated by the vacuum chamber. The expansion chamber 106 is the portion of the shaft 104 that is not insulated by the vacuum and defines the portion where the ice ball is generated. In various embodiments, the flexible shaft transports a high-pressure working fluid from the handle 102 to the expansion chamber 106, where it undergoes Joule-Thomson expansion and the corresponding temperature change. The working fluid travels down the flexible shaft, through the handle, and is discharged into the atmosphere from the console, or enters the handle and is discharged from the handle.

[0038] The distal end of the shaft may terminate with a distal working tip 108. During use, the distal working tip 108 is positioned in the patient's body, surrounded by tissue, and possibly to ablate the tissue at cryogenic temperatures. The distal working tip 108 may, advantageously, be configured to puncture tissue in some examples. For example, the distal working tip 108 may include a sharp tip, such as a trocar tip. Alternatively, the distal working tip 108 may not have a sharp tip. In some embodiments, the distal working tip 108 may be a non-traumatic tip designed to cause minimal tissue damage. In some embodiments, the distal working tip 108 may include a working port configured for aspiration, delivery of therapeutic drugs, and delivery of other devices, including but not limited to guidewires, imaging catheters, sensing devices, biopsy devices, balloons, and stents.

[0039] [Handle equipped with a pre-cooling circuit (Figure 2)] Referring to Figure 2, schematic diagrams of some of the refrigeration ablation systems according to various embodiments of the present disclosure are shown. In some embodiments, the refrigeration ablation system 100 may include a working fluid source 110 connected to a working fluid circuit and a pre-cooler fluid source 112 connected to a pre-cooler fluid circuit. The working fluid circuit may include a working fluid supply conduit 210 for transporting a high-pressure flow of working fluid from the working fluid source 110 to the distal end of the shaft 104 (not shown in this figure). The working fluid circuit may also include a working fluid return conduit (not shown in this figure) for returning a low-pressure flow of working fluid from the distal end of the shaft to the base of the handle 102.

[0040] The precooler fluid circuit may include a precooler supply circuit 212 that terminates at a precooler Joule-Thomson orifice 223 and delivers a high-pressure flow of precooler fluid from a precooler fluid source 112 to the precooler fluid expansion region 222 within the handle 102. The precooler fluid circuit may also include a precooler return conduit (indicated by arrow 213). The precooler return conduit may be configured to deliver precooler fluid away from the precooler fluid expansion region 222 back to the base of the handle 102. The precooler return conduit may be housed together with the precooler supply circuit 212 and extend back to the control console and gas manifold.

[0041] In various embodiments, a pre-cooler fluid circuit can facilitate heat exchange between the working fluid and the pre-cooler fluid. For example, in embodiments where the working fluid cools during expansion to cryogenically ablate the tissue around the distal working tip 108, a pre-cooler fluid circuit can be used to pre-cool the high-pressure flow of the working fluid. In various embodiments, the working fluid supply conduit 210 may include a first heat exchanger 216. The first heat exchanger 216 can facilitate heat exchange between the high-pressure flow of the working fluid in the working fluid supply conduit 210 and the low-pressure flow of the pre-cooler fluid in the pre-cooler return conduit.

[0042] In various embodiments, the precooler supply conduit 212 may include a second heat exchanger 218 that enables heat exchange (e.g., regenerative heat exchange) between a high-pressure flow of precooler fluid and a low-pressure flow of precooler fluid. In some embodiments, the precooler fluid may be a cooling fluid. In such embodiments, heat can be removed from the high-pressure flow of precooler fluid by regenerative heat exchange between the high-pressure flow of precooler fluid and the low-pressure flow of precooler fluid. Thus, the second heat exchanger 218 can facilitate the precooling of the high-pressure flow of precooler fluid.

[0043] In various embodiments, the high-pressure precooler fluid flowing out of the second heat exchanger 218 continues to flow through the precooler supply conduit 212 into the precooler fluid expansion region 222. In the precooler fluid expansion region, which is entirely contained within the handle 102, the precooler supply conduit 212 terminates at a Joule-Thomson orifice. The high-pressure precooler fluid flow may expand at or downstream of the Joule-Thomson orifice within the precooler fluid expansion region 222. This rapid decrease in pressure causes a corresponding decrease in temperature. The precooler fluid expansion region 222 may be in fluid communication with a precooler return conduit to transport the expanded low-pressure precooler fluid flow (for example, to discharge into the atmosphere if the precooler fluid circuit is open, or to return to the precooler fluid source if the precooler fluid circuit is closed). After expanding in the Joule-Thomson orifice, the cooled precooler fluid returns through the handle 102 in the annular space between the core tube 215 and the outer surface of the handle 102. As the precooler fluid passes through the precooler return conduit, it cools the working fluid in the first heat exchanger 216.

[0044] The working fluid circuit 210 may further include a third heat exchanger 220 in the shaft 104 of the refrigeration ablation system configured to perform heat exchange (e.g., regenerative heat exchange) between the high-pressure flow of working fluid in the working fluid supply circuit 210 and the low-pressure flow of working fluid (not shown in this figure) returning through the shaft 104.

[0045] [Details of the distal tip and inflation chamber (Figure 3)] Referring to Figure 3, schematic diagrams of some of the cryoablation shafts according to various embodiments of the present disclosure are shown. In various embodiments, the shaft includes an insulated region 105 and an expansion chamber 106. In various embodiments, the insulated region 105 of the shaft 104 includes a supply pipe 324 located within a return pipe 326 located within an insulated shaft 328. A concentric shaft structure is designed to isolate the working fluid circuit 210 and the vacuum chamber 336 from each other.

[0046] In various embodiments, the high-pressure flow of working fluid travels down the supply pipe 324 after exiting the handle 102. When the working fluid reaches the working fluid expansion chamber 106, the supply pipe 324 terminates at a Joule-Thomson orifice 332 or distal outlet 332. The high-pressure flow of working fluid may undergo expansion in the Joule-Thomson orifice 332 within the expansion chamber 106, or downstream thereof. This rapid decrease in pressure causes a corresponding decrease in temperature. Heat transfer between the expanded working fluid and the outer wall of the expansion chamber 106 causes ice balls to form in the tissue around the tip 108, resulting in cryoablation of the tissue.

[0047] The expansion chamber 106 may be in fluid communication with a working fluid return conduit (defined by the annular space between the supply pipe 324 and the inner surface of the return pipe 326 of the expansion chamber) to transport the expanded low-pressure flow of working fluid (for example, to discharge it into the atmosphere if the working fluid circuit is open, or to return it to the working fluid source if the working fluid circuit is closed). As the working fluid passes through the working fluid return conduit, it cools the working fluid input flow in the third heat exchanger 220 (Figure 2).

[0048] In various embodiments, the working fluid is a cooling fluid and / or cooling gas (e.g., nitrogen, air, argon, krypton, xenon, N2O, CO2, CF4). In this case, the working fluid in the high-pressure flow may be at a pressure at which expansion through the Joule-Thomson orifice 332 cools the working fluid to a temperature at which cryogenic ablation occurs in the tissue surrounding the expansion chamber 106. In certain embodiments, the pressure of the working fluid in the high-pressure flow upstream of the Joule-Thomson orifice 332 may be about 6.9 MPa to about 13.8 MPa (e.g., about 12.4 MPa). Therefore, in embodiments where the working fluid is a cooling fluid, the temperature of the working fluid after expansion exiting the Joule-Thomson orifice 332 may be 150 Kelvin, 160 Kelvin, 170 Kelvin, 180 Kelvin, 190 Kelvin, or 200 Kelvin or higher, or within a range of any of these values.

[0049] The cryoablation system 100 may be designed so that the outermost surface of the shaft does not cause thermal damage to non-target structures. In various embodiments, ice ball formation is limited to the expansion chamber 106 of the shaft 104, which may also be referred to as the operating region of the apparatus. Selective ice ball formation is achieved by vacuuming through the insulated region 105 of the shaft 104. In various embodiments, the cryoablation system 100 may be configured to establish a vacuum communication between the shaft 104 and the vacuum source 114.

[0050] Referring again to Figure 1, the cryoablation system 100 may be configured to connect to a vacuum source 114 at the handle 102. In various embodiments, the vacuum source 114 is configured to evacuate along the length of the insulated region 105 of the shaft 104. In one embodiment, the entire insulated region 105 of the shaft 104 is evacuated between the outer diameter of the return pipe 326 and the inner diameter of the insulated shaft 328.

[0051] In various embodiments, the vacuum source 114 is configured to evacuate within at least a portion of the handle 102. Such a configuration can insulate the handle 102 and protect the operator of the refrigeration ablation system from cryogenic exhaust gases. In some embodiments, the vacuum source 114 is connected to the handle 102, and the space between the supply pipe 324 and the return pipe 326 can be evacuated by evacuating the inside of the handle 102, by fluid communication between the shaft 104 and the handle 102. In other embodiments, the vacuum source 114 is connected directly to the shaft 104, for example, using a T-fitting along the length of the shaft 104.

[0052] To provide thermal insulation along the insulated region 105 of shaft 104, the wall of the flexible shaft is a double wall (return tube surrounded by the insulated shaft) with a small gap between the return tube 326 and the insulated shaft 328. By preventing convective heat transfer by vacuuming the space between the return tube and the insulated shaft, the temperature of the working fluid does not cause ablation of healthy non-target patient tissue along the insulated region of the shaft or induce uncontrolled apoptosis / necrosis. Sufficient insulation is achieved by actively evacuating the air in the gap and maintaining a vacuum of about 0.05 Torr. However, depending on the configuration of the cryoablation system, other vacuum pressures may be appropriate. In some embodiments, a support filament 330 is wound along the outer diameter of the return tube 326. One choice of filament material is a polymer such as polyetheretherketone (PEEK). The filament can prevent direct contact between the outer surface of the return tube and the inner surface of the insulated shaft. The filament 330 minimizes heat conduction between the inner shaft and the insulated shaft. Instead of filament 330, other alternatives may be used, such as an extruded tube / co-extruded shape or other features positioned on a shaft.

[0053] In some embodiments, the shaft may not include a filament. In such embodiments, the return tube 326 and the insulated shaft 328 are selected to have material properties sufficient to minimize heat conduction between the inner shaft and the insulated shaft.

[0054] The joint 334 is located at the junction of the insulating region 105 and the expansion chamber 106. This joint can seal the vacuum layer. [Cross section, dimensions, and material of a flexible shaft (Figure 4)] Referring to Figure 4, a cross-sectional view of the shaft of Figure 3 obtained along section 4-4 according to various embodiments of the present disclosure is shown. In various embodiments, the insulated region 105 of the shaft 104 includes a supply pipe 324 concentrically located within a return pipe 326 concentrically located within an insulated shaft 328. The insulated region 105 may include the shaft portion of the vacuum chamber 336 and the insulated portion of the working gas circuit 210. In various embodiments, the vacuum chamber 336 surrounds and isolates the insulated portion of the working gas circuit 210 from the insulated portion.

[0055] In various embodiments, after exiting the handle 102, the high-pressure working fluid flows distally through the adiabatic region of the shaft via the supply pipe 324. After cooling and expanding in the expansion chamber 106, the working fluid returns proximal through the adiabatic region 105 of the shaft 104 in the annular space between the supply pipe 324 and the return pipe 326.

[0056] In various embodiments, the material and dimensions of each layer of the shaft 104 may be selected to have a degree of flexibility sufficient to allow the shaft to bend about its longitudinal axis at the operating temperature of the apparatus.

[0057] In various embodiments, the supply tube 324, which may also be referred to herein as a capillary tube, is made of any suitable material such as a flexible metal, polymer, or composite material. In one embodiment, the supply tube 324 is made of nitinol (NiTi), stainless steel, or the like.

[0058] In some embodiments, the inner diameter of the supply pipe 324 may be 0.30 mm, 0.35 mm, 0.40 mm, or 0.45 mm or more. In some embodiments, the inner diameter of the supply pipe 324 may be 0.60 mm, 0.55 mm, 0.50 mm, or 0.45 mm or less. In some embodiments, the diameter of the supply pipe 324 may be in the range of 0.30 mm to 0.60 mm, in the range of 0.35 mm to 0.55 mm, in the range of 0.40 mm to 0.50 mm, or about 0.45 mm.

[0059] In some embodiments, the outer diameter of the supply pipe 324 may be 0.38 mm, 0.43 mm, 0.48 mm, 0.53 mm, or 0.58 mm or more. In some embodiments, this outer diameter may be 0.78 mm, 0.73 mm, 0.68 mm, 0.63 mm, or 0.58 mm or less. In some embodiments, this outer diameter may be in the range of 0.38 mm to 0.78 mm, in the range of 0.43 mm to 0.73 mm, in the range of 0.48 mm to 0.68 mm, in the range of 0.53 mm to 0.63 mm, or about 0.58 mm.

[0060] In some embodiments, the thickness of the supply pipe 324 may be 0.10 mm, 0.11 mm, 0.12 mm, 0.14 mm, or 0.15 mm or more. In some embodiments, the thickness of the supply pipe 324 may be 0.20 mm, 0.19 mm, 0.18 mm, 0.16 mm, or 0.15 mm or less. In some embodiments, the thickness of the supply pipe 324 may be in the range of 0.10 mm to 0.20 mm, in the range of 0.11 mm to 0.19 mm, in the range of 0.12 mm to 0.18 mm, in the range of 0.14 mm to 0.16 mm, or about 0.15 mm.

[0061] In various embodiments, the return tube 326 is composed of any suitable material or combination of materials, such as flexible metal or polymer. In various embodiments, the return tube 326 may be made of polyimide, fluorinated ethylene propylene (FEP), Teflon®, etc. In one embodiment, the return tube 326 is formed from a polyimide material to have high gas impermeability over a wide temperature range, thereby allowing a vacuum to be maintained on the outside while accommodating the working fluid inside. In certain examples, the return tube 326 is made from a braided-reinforced polyimide tube to enhance gas impermeability, burst strength, and flexibility. In some embodiments, the return tube 326 is formed from a single layer of material. In some embodiments, the return tube 326 may be formed from two or more material layers selected to optimize the performance of the shaft 104. These material layers may be joined to each other using any suitable one or more techniques, such as adhesives or reflow processes.

[0062] In some embodiments, the outer diameter of the return pipe 326 may be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.4 mm or more. In some embodiments, the outer diameter of the return pipe 326 may be 1.8 mm, 1.7 mm, 1.6 mm, 1.5 mm, or 1.4 mm or less. In some embodiments, the outer diameter of the return pipe 326 may be in the range of 1.0 mm to 1.8 mm, 1.1 mm to 1.7 mm, 1.2 mm to 1.6 mm, 1.3 mm to 1.5 mm, or about 1.4 mm.

[0063] In some embodiments, the inner diameter of the return pipe 326 may be 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, or 1.3 mm or more. In some embodiments, the inner diameter of the return pipe 326 may be 1.7 mm, 1.6 mm, 1.5 mm, 1.4 mm, or 1.3 mm or less. In some embodiments, the inner diameter of the return pipe 326 may be in the range of 0.9 mm to 1.7 mm, in the range of 1.0 mm to 1.6 mm, in the range of 1.1 mm to 1.5 mm, in the range of 1.2 mm to 1.4 mm, or about 1.3 mm.

[0064] In some embodiments, the thickness of the return tube 326 may be 0.10 mm, 0.11 mm, 0.12 mm, 0.14 mm, or 0.15 mm or more. In some embodiments, the thickness of the return tube 326 may be 0.20 mm, 0.19 mm, 0.18 mm, 0.16 mm, or 0.15 mm or less. In some embodiments, the thickness of the return tube 326 may be in the range of 0.10 mm to 0.20 mm, in the range of 0.11 mm to 0.19 mm, in the range of 0.12 mm to 0.18 mm, in the range of 0.14 mm to 0.16 mm, or about 0.15 mm.

[0065] In various embodiments, the insulated shaft 328 is made of any suitable material such as a flexible metal or polymer. In various embodiments, the insulated shaft 328 is made of polyimide, fluorinated ethylene propylene (FEP), Teflon®, etc. In certain embodiments, the insulated shaft 328 may include polytetrafluoroethylene (PTFE) and / or one or more polyether block amides (trade name Pebax®, hereinafter known as "Pebax").

[0066] In some embodiments, the insulated shaft 328 is formed from a single layer of material. In some embodiments, the insulated shaft 328 may be formed from two or more layers of material selected to optimize the performance of the shaft 104. These layers of material may be joined to each other using one or more suitable techniques, such as adhesives or reflow processes.

[0067] In one embodiment, the insulated shaft may be formed using a braided-reinforced polyimide tube coated with an outer layer of Pebax. Such a three-layer structure allows a high vacuum to be maintained between the return tube and the insulated shaft without the insulated shaft 328 collapsing on the return tube 326.

[0068] In some embodiments, the outer diameter of the insulating shaft 328 may be 1.2 mm, 1.4 mm, 1.5 mm, 1.6 mm, or 1.8 mm or more. In some embodiments, the outer diameter of the insulating shaft may be 2.2 mm, 2.1 mm, 2.0 mm, 1.9 mm, or 1.8 mm or less. In some embodiments, the outer diameter of the insulating shaft may be in the range of 1.3 mm to 2.3 mm, 1.4 mm to 2.1 mm, 1.5 mm to 2.0 mm, 1.6 mm to 1.9 mm, or about 1.8 mm.

[0069] In some embodiments, the inner diameter of the insulating shaft 328 may be 1.0 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.6 mm or more. In some embodiments, the inner diameter of the insulating shaft 328 may be 2.2 mm, 2.0 mm, 1.9 mm, 1.8 mm, or 1.6 mm or less. In some embodiments, the inner diameter of the insulating shaft 328 may be in the range of 1.0 mm to 2.2 mm, 1.2 mm to 2.0 mm, 1.3 mm to 1.9 mm, 1.4 mm to 1.8 mm, or about 1.6 mm.

[0070] In some embodiments, the thickness of the insulating shaft 328 may be 0.10 mm, 0.11 mm, 0.12 mm, 0.14 mm, or 0.15 mm or more. In some embodiments, the thickness of the insulating shaft 328 may be 0.20 mm, 0.19 mm, 0.18 mm, 0.16 mm, or 0.15 mm or less. In some embodiments, the thickness of the insulating shaft 328 may be in the range of 0.10 mm to 0.20 mm, in the range of 0.11 mm to 0.19 mm, in the range of 0.12 mm to 0.18 mm, in the range of 0.14 mm to 0.16 mm, or about 0.15 mm.

[0071] In some embodiments, PEEK filaments 330 are wound around the return tube 326. The PEEK filaments 330 may have a pitch of 0.5 mm, 1.0 mm, 1.5 mm, or 2.0 mm or more, or a pitch within a range of any of these values. Alternatively, the filaments may be multiple separate parts mounted along the return tube 326. The PEEK filaments 330 maintain their coaxial arrangement by preventing direct contact between the return tube 326 and the insulated shaft 328. In some embodiments, an adhesive (e.g., LOCTITE®) is applied to the filaments at the ends of the return tube 326 and the insulated shaft 328 to attach the PEEK filaments 330. In various embodiments, the winding of the PEEK filaments is configured to minimize or prevent conductive heat transfer from the return tube to the insulated shaft. In alternative embodiments, other insulating polymers such as stretched PTFE (ePTFE) and nylon may be used as substitutes for the PEEK filaments.

[0072] In some embodiments, the diameter of the PEEK filament 330 may be 0.002 mm, 0.004 mm, or 0.005 mm or more. In some embodiments, the diameter of the PEEK filament 330 may be 0.007 mm, 0.006 mm, or 0.005 mm or less. In some embodiments, the diameter of the PEEK filament 330 may be in the range of 0.002 mm to 0.007 mm, in the range of 0.004 mm to 0.006 mm, or about 0.005 mm.

[0073] [Shaft inside the expansion chamber (Figure 5)] Referring to Figure 5, a cross-sectional view of the shaft of Figure 3 obtained along cross-section 5-5 according to various embodiments of the present disclosure is shown. The cross-sectional view of Figure 5 shows the expansion chamber 106 of the shaft 104. In various embodiments, the expansion chamber 106 is located distal to the adiabatic region 105 along the shaft 104. The expansion chamber 106 may include the expansion portion of the working fluid circuit 210.

[0074] In various embodiments, the high-pressure working fluid flows down the supply pipe 324 after exiting the handle 102. After cooling and expanding in the expansion chamber 106, the working fluid returns downward through the expansion chamber 106 in the annular space between the supply pipe 324 and the outer wall of the expansion chamber. In various embodiments, the expansion chamber 106 is configured to maximize heat transfer between the working gas and the patient's tissue through the optimization of parameters such as wall thickness and material.

[0075] In various embodiments, the expansion chamber 106 is made of any suitable material or combination of materials, such as a flexible metal or polymer. In various embodiments, the expansion chamber 106 is made of polyimide, fluorinated ethylene propylene (FEP), Teflon®, etc. In some embodiments, the expansion chamber 106 includes an extension of the return tube 326 in the insulated region 105 of the shaft 104. Alternatively, the expansion chamber is a separate component from the return tube 326 and can be joined to the shaft 104 using any suitable joining and / or fitting, such as reflow soldering, adhesive bonding, soldering, or any other suitable mechanical joining process capable of withstanding cryogenic pressure and temperature.

[0076] In some embodiments, the expansion chamber 106 is formed from a single material layer. In some embodiments, the expansion chamber 106 is formed from two or more material layers. These material layers can be joined to each other using any suitable one or more techniques, such as adhesives or reflow processes.

[0077] In some embodiments, the outer diameter of the expansion chamber 106 may be 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, or 1.7 mm or more. In some embodiments, the outer diameter of the expansion chamber 106 may be 2.1 mm, 2.0 mm, 1.9 mm, 1.8 mm, or 1.7 mm or less. In some embodiments, the outer diameter of the expansion chamber 106 may be in the range of 1.3 mm to 2.1 mm, 1.4 mm to 2.0 mm, 1.5 mm to 1.9 mm, 1.6 mm to 1.8 mm, or about 1.7 mm.

[0078] In some embodiments, the inner diameter of the expansion chamber 106 may be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.4 mm or more. In some embodiments, the inner diameter of the expansion chamber 106 may be 1.8 mm, 1.7 mm, 1.6 mm, 1.5 mm, or 1.4 mm or less. In some embodiments, the inner diameter of the expansion chamber 106 may be in the range of 1.0 mm to 1.8 mm, 1.1 mm to 1.7 mm, 1.2 mm to 1.6 mm, 1.3 mm to 1.5 mm, or about 1.4 mm.

[0079] In some embodiments, the wall thickness of the expansion chamber 106 may be 0.20 mm, 0.22 mm, 0.25 mm, 0.28 mm, or 0.30 mm or more. In some embodiments, the wall thickness of the expansion chamber 106 may be 0.40 mm, 0.38 mm, 0.35 mm, 0.32 mm, or 0.30 mm or less. In some embodiments, the wall thickness of the expansion chamber 106 may be in the range of 0.20 mm to 0.40 mm, in the range of 0.22 mm to 0.38 mm, in the range of 0.25 mm to 0.35 mm, in the range of 0.28 mm to 0.32 mm, or about 0.30 mm.

[0080] [Examples of treatment areas (Figure 6)] The cryoablation systems and structures described herein are flexible and are highly suitable for cryoablation of areas along lumens, blood vessels, or passages of the body. The cryoablation system 100 is configured to be sufficiently flexible to access and ablate many different such structures. The inflation chamber may have a shape and size that produces a geometrically shaped ice ball or ice column suitable for ablating structures along the length of a body lumen. Furthermore, the materials and structures of the probes described herein are selected to protect patient tissue and withstand high operating pressures and low temperatures.

[0081] Referring to Figure 6, schematic diagrams of the biliary system according to various embodiments of the present disclosure are shown. The biliary system includes organs and tubules that produce, store, and release bile (a fluid produced by the liver that helps digest fats) into the small intestine. The biliary system includes the gallbladder, as well as the bile ducts inside and outside the liver.

[0082] Cholangiocarcinoma, or cholangiocarcinoma, is a rare disease in which cancer cells form in the bile ducts. The treatment outcomes for cholangiocarcinoma are generally poor. Current treatment options (e.g., Whipple surgery or biliary drainage) are high-risk and often ineffective.

[0083] Cryoablation is a promising treatment for cholangiocarcinoma. This cryoablation system 100 is configured to be flexible enough to access and ablate the patient's bile duct. The expansion chamber may have a shape and size that produces an ice ball with a suitable geometric shape for resecting tumors within the bile duct.

[0084] In addition to treating cholangiocarcinoma, the cryoablation system 100 can be used to treat several conditions, including other cancerous tumors (e.g., skin, liver, kidney, bone, lung, prostate, and breast), pain, skin conditions (e.g., atypical moles, warts, skin tags, or actinic keratosis), and arrhythmias. The cryoablation system 100 can also ablate benign tumors, soft tissue, and healthy tissue.

[0085] [Ice ball formation (Figure 7)] Referring to Figure 7, schematic diagrams of the growth of ice balls produced by cryoablation systems according to various embodiments of this disclosure are shown. Cryoablation is defined as cell destruction at low temperatures. Ice balls are formed in the expansion chamber of the cryoablation system, freezing intracellular and extracellular material to temperatures below 173 Kelvin. The application of these extremely low temperatures induces cell death. Ablation temperatures low enough to induce complete cell death are achieved. Lethal temperatures for various tissues have been reported to be between 253 Kelvin and 233 Kelvin.

[0086] Figure 7 shows the growth of the ice ball over the course of the cryoablation procedure. The times in this example are 60 seconds, 120 seconds, 180 seconds, and 240 seconds. Isotherms of 273 Kelvin, 253 Kelvin, and 233 Kelvin are shown for each time period. As the cryoablation procedure progresses over time, the overall ice ball size increases. More importantly, the isotherms of cell death (253 Kelvin and 233 Kelvin isotherms) grow along both the long and short axes of the ice ball.

[0087] The times and temperatures given in Figure 7 are intended for illustrative purposes only. Ice ball formation may be modified based on the cryoablation system and the structure of the patient's tissue. Ice ball growth may also stabilize after reaching a specific ablation time. For example, in some embodiments, the ice ball may reach its maximum diameter after ablation of the tissue for about 10 minutes. In some embodiments, the operator of the cryoablation system may terminate the cryoablation procedure when the ice ball reaches its maximum size. In some embodiments, since keeping the tissue at a cryogenic temperature for a longer period of time may have therapeutic benefits, the operator of the cryoablation system may continue the cryoablation procedure even after the ice ball has reached its maximum size over a predetermined period of time.

[0088] In some embodiments, an ice ball is formed, and then, upon thawing, it is formed again. In some embodiments, an active thawing method is used, while in other embodiments, a passive thawing method is used.

[0089] In the example in Figure 7, the ice ball is elliptical (for example, the ice ball is longer along the first axis than along the second axis). The first axis of the ice ball corresponds to the longitudinal axis of the expansion chamber. The ratio of height to diameter of the expansion chamber can correlate with the shape of the ice ball. In particular, an expansion chamber that is much longer than its width results in a more oval ice ball. Such ice balls are more compatible with the anatomical structure of the bile duct and are therefore generally more suitable for the treatment of cholangiocarcinoma. However, other cryoablation applications may require a more spherical ice ball. In such cases, the expansion chamber can be modified to have a smaller length-to-diameter ratio.

[0090] In some embodiments, the major axis length of the ice ball may be 0.5 mm, 2 mm, 4 mm, 6 mm, 8 mm, or 10 mm or more, or within a range of any of these. In some embodiments, the minor axis length of the ice ball may be 0.5 mm, 2 mm, 4 mm, 6 mm, 8 mm, or 10 mm or more, or within a range of any of these.

[0091] [Cryoablation shaft including slotted tube section, polymer layer, and reinforcing layer (Figure 8)] Referring to Figure 8, schematic diagrams of the tip portions of cryoablation shafts according to various embodiments of the present disclosure are shown. In various embodiments, the shaft includes an insulated region 105 and an expansion chamber 106. In various embodiments, the insulated region 105 of the shaft 104 includes a supply pipe 324 concentrically located within a return pipe 326 concentrically located within an insulated shaft 328. The concentric shaft structure is designed to isolate the working gas circuit and the active vacuum circuit from each other.

[0092] In various embodiments, the high-pressure working fluid flows down the supply pipe 324 after exiting the handle 102. The high-pressure working fluid undergoes expansion in or downstream of the Joule-Thomson orifice 332 and can return through the shaft in the annular space between the supply pipe 324 and the return pipe 326.

[0093] In various embodiments, the expansion chamber 106 of the shaft 104 includes a supply pipe 324 concentrically located within a return pipe 326. In various embodiments, the return pipe 326 includes multiple layers.

[0094] In various embodiments, the innermost layer of the return tube is a slotted tube 830, which includes slots 840 along at least a portion of the length of the shaft 104. The slots 840 are formed in the tube material by any suitable means, such as laser cutting. The slots 840 may be laser-cut in the shaft using any suitable pattern to optimize the strength and flexibility of the return tube 326. The material of the slotted tube 830 may be a metal, such as stainless steel, Nitinol, or other durable material. Many different configurations and patterns of the slotted tube 830 are also available, and one may be selected to have the desired flexibility for its application. In various embodiments, the slotted tube forms the core of the return tube 326.

[0095] In some embodiments, the slotted tube 830 contains slots only within the expansion chamber 106. In this embodiment, the portion of the slotted tube 830 extending into the insulated region 105 has a solid wall. Figure 8 shows a schematic side view of the slotted tube 830 including slots 840 within the expansion chamber 106, with the supply tube 324 within the slotted tube 830 indicated by a dashed line. In an alternative embodiment, the slotted tube 830 has slots along its entire length.

[0096] The slotted tube may be configured to have sufficient flexibility to form a curve with a desired radius of curvature. For example, the slotted tube may have sufficient flexibility so that the shaft can form a curve with a minimum radius of curvature of 30 mm, 20 mm, 10 mm, 5 mm, or 3 mm or less. The slotted tube 830 may have different levels of flexibility in the expansion chamber and the insulated region 105.

[0097] In various embodiments, the first polymer layer 842 surrounds a portion of the slotted tube 830, which includes slots, for accommodating the working fluid within the shaft 104. In various embodiments, a reinforcing layer 844 surrounds the first polymer layer 842 and is configured to reduce the possibility of leakage or rupture in the first polymer layer by reinforcing the first polymer layer 842 with additional strength.

[0098] In various embodiments, the first polymer layer 842 may be formed from any suitable polymer such as polyethylene terephthalate (PET), PTFE, ePTFE, PEEK, polyetherimide (PEI), or polyimide (PI). In various embodiments, the reinforcing layer 844 may be a second polymer layer formed from any suitable polymer such as PET, PTFE, PEEK, polyetherimide (PEI), or polyimide (PI). In various embodiments, the reinforcing layer is gas impermeable. In various embodiments, the reinforcing layer 844 is not impermeable and may contain braided polymer material, and / or coiled polymer or metallic material, and / or coating and sealing material.

[0099] In various embodiments, the number of polymer layers in the return tube may be two, three, four, or more. In various embodiments, the total number of layers in the return tube may be two, three, four, or more.

[0100] In the embodiment shown in Figure 8, where the slotted portion of the slotted tube 830 is located within the expansion chamber, the first polymer layer 842 and the reinforcing layer 844 extend from within the heat insulating region 105 to the distal end. In various embodiments, the first polymer layer 842 is joined to the slotted tube 830 at a first joint 846 near the proximal end of the expansion chamber 106 and a second joint 848 near the tip 108 of the shaft 104.

[0101] In various embodiments, the reinforcing layer 844 is joined to the slotted tube 830 at a first joint 847 near the proximal end of the expansion chamber 106 and / or a second joint 849 near the tip 108 of the shaft 104.

[0102] Additional joints may be positioned along any other suitable location on the shaft. The joints can be formed from any suitable material such as Vectran, UHMWPE, PEEK, polyimide, or metal wire. Vectran is a synthetic fiber spun from a liquid crystal polymer that exhibits high tensile strength at low temperatures and is advantageous for use in cryoablation systems. In alternative embodiments, joints 846, 847, 848, and 849 can be formed by alternative methods such as crimping or scribing rings, polymer reflow bonding, adhesive bonding, or soldering.

[0103] In various embodiments, the coating material for joints 846, 847, 848, 849 may be applied along the entire length of the expansion chamber around a polymer layer, a reinforcing layer, or both. The coating layer may have a higher coating pitch at the joint location and extend along the rest of the expansion chamber at a lower pitch level. The coating layer may extend from the proximal end to the distal end, then reverse direction and extend back towards the proximal end. The number of coating layers may be one, two, three, four, or more.

[0104] In various embodiments, the joints 846, 847, 848, and 849 are configured to increase the burst strength of the layers of the return pipe 326. In some embodiments, the burst strength of the first polymer layer 842 and the reinforcing layer 844 may be 12.4 MPa, 13.1 MPa, 13.8 MPa, 14.5 MPa, 15.2 MPa, or 41.4 MPa or higher. In some embodiments, the burst strength of the first polymer layer 842 and the reinforcing layer may be 41.4 MPa, 20.7 MPa, 19.3 MPa, 17.9 MPa, 16.5 MPa, or 15.2 MPa or lower. In some embodiments, this burst strength may be in the range of 12.4 MPa to 41.4 MPa, 13.1 MPa to 27.6 MPa, 13.8 MPa to 17.9 MPa, 14.5 MPa to 16.5 MPa, or about 15.2 MPa.

[0105] In some embodiments, the burst strength of the bonded first polymer layer 842 and reinforcing layer 844 may be 12.4 MPa, 13.1 MPa, 13.8 MPa, 14.5 MPa, 15.2 MPa, 27.6 MPa, or 41.4 MPa or higher. In some embodiments, the burst strength of the bonded first polymer layer 842 and reinforcing layer 844 may be 41.4 MPa, 20.7 MPa, 19.3 MPa, 17.9 MPa, 16.5 MPa, or 15.2 MPa or lower. In some embodiments, the burst strength of the bonded first polymer layer 842 and reinforcing layer 844 may be in the range of 12.4 MPa to 41.4 MPa, in the range of 13.1 MPa to 27.6 MPa, in the range of 13.8 MPa to 17.9 MPa, in the range of 14.5 MPa to 16.5 MPa, or about 15.2 MPa.

[0106] In some embodiments, the burst strength of each joint 846, 847, 848, and 849 may be 1.4 MPa, 4.8 MPa, 8.3 MPa, 11.7 MPa, 15.2 MPa, 27.6 MPa, or 41.4 MPa or higher. In some embodiments, the burst strength of each joint may be 41.4 MPa, 34.8 MPa, 28.3 MPa, 21.7 MPa, or 15.2 MPa or lower. In some embodiments, the burst strength of each joint may be in the range of 1.4 MPa to 41.4 MPa, in the range of 4.8 MPa to 34.8 MPa, in the range of 8.3 MPa to 28.3 MPa, in the range of 11.7 MPa to 21.7 MPa, or about 15.2 MPa.

[0107] In some embodiments, joints 846, 847, 848, and 849 may have the same burst strength. Alternatively, some of these joints may have a higher burst strength than others. For example, the proximal joints 846 and 847 may have a lower burst strength than the distal joints 848 and 849.

[0108] In various embodiments, the return tube 326 may be configured to be flexible enough to form a curve having a desired radius of curvature. For example, the return tube may be flexible enough so that the shaft can form a curve having a minimum radius of curvature of 30 mm, 20 mm, 10 mm, 5 mm, or 3 mm or less.

[0109] [A slotted tube section that can extend along the entire length of the return tube] Figure 8 shows that the slotted tube 830 contains slots only within the expansion chamber 106, but in an alternative embodiment, the slotted tube 830 has slots along its entire length. In this alternative embodiment, the first polymer layer 842 and the reinforcing layer 844 extend along the entire length of the return tube 326. A reinforcing coating layer, such as a Vectran material coating, may also extend along the entire length of the return tube. It may be desirable to have slots along the entire length of the return tube in order to achieve a desired level of flexibility along the return tube.

[0110] [Refrigerated ablation shaft including slotted pipe section and gradient braid (Figure 9)] Referring to Figure 9, schematic diagrams of some of the cryoablation shafts according to various embodiments of the present disclosure are shown. In various embodiments, the shaft includes an insulated region 105 and an expansion chamber 106. In various embodiments, the insulated region 105 of the shaft 104 includes a supply pipe 324 located within a return pipe 326. The return pipe 326 in Figure 9 includes multiple layers.

[0111] The innermost layer of the return pipe 326 is a slotted pipe 830, which may be constructed using any optional configuration and detailed configuration described herein. The slotted pipe 830 is surrounded by a polymer layer 956, which is concentrically surrounded by a reinforcing gradient braided layer 940.

[0112] In various embodiments, the gradient braided layer 940 includes regions of different braiding densities, with the density increasing toward the distal end of the apparatus. The first braided region 958 is located within the insulating region and has the lowest density. The second braided region 960 overlaps the insulating region 105 and the expansion chamber 106 and is denser than the first braided region 958. The third braided region 962 has the highest density and is located within the expansion region. The return pipe may include one, two, three, or more braided layers.

[0113] In various embodiments, the polymer layer 956 is configured to contain the working fluid in the return tube while preventing the working fluid from escaping radially through the slots in the slotted tube. The polymer layer may consist of the options and materials described herein with respect to the first polymer layer. In some embodiments, the expansion chamber 106 may include an additional braided layer between the slotted tube 830 and the polymer layer 956 (not shown in this figure). The additional braided layer is configured to prevent friction between the polymer layer 956 and the slotted tube 830.

[0114] [Examples of braided materials, braided element diameters, braided density regions, coils, and burst strengths] Braided tubing is used in a variety of medical applications. Braided reinforcement can improve the functional properties of medical devices, such as strength, rigidity, rupture pressure resistance, torque transmission, and torsional resistance. These features can allow the cryoablation shaft to move through tortuous sections of the patient's anatomical structures, such as the bile duct. Design considerations such as braid pattern, pick count (ppi), material, wire dimensions, wire size / shape, and resin durometer can significantly affect the device's performance.

[0115] The braided portion of the shaft can be formed from any suitable material such as metal (e.g., Nitinol, stainless steel, tungsten, MP35N, or other such materials), polymer (e.g., PET, Kevlar, carbon fiber, Vectran, or other such materials). The braided material is formed by weaving metal or fiber filaments in a braided pattern. In various embodiments, the cross-section of the filaments is circular, but other cross-sectional shapes (e.g., flat, star-shaped, triangular) are also possible. In some embodiments, the diameter of the filaments may be 0.01 mm, 0.1 mm, 0.2 mm, 0.3 mm, or 0.5 mm or more. In some embodiments, the diameter of the filaments may be 2 mm, 1.6 mm, 1.2 mm, 0.8 mm, or 0.5 mm or less. In some embodiments, the diameter of the filaments may be in the range of 0.01 mm to 2.00 mm, 0.1 mm to 1.6 mm, 0.2 mm to 1.2 mm, 0.3 mm to 0.8 mm, or about 0.5 mm.

[0116] In various embodiments, the density of the braided portion can be varied so that high-density braids increase radial strength and rigidity, while low-density braids provide flexibility. The shaft may include multiple braids having various material properties. In various embodiments, the shaft may include a lightweight braid (for example, having a relatively low braid density) between the return tube 326 and the polymer layer 956. As described above, the lightweight braid can prevent excessive friction between the slotted return tube 326 and the polymer layer 956, although structural support is limited.

[0117] In various embodiments, the density of the braided material can increase from the base of the shaft 104 to the tip 108 of the shaft. Such a configuration increases the likelihood that the shaft will fail closer to the base if the device malfunctions. This type of failure is generally preferable from the viewpoint of patient safety compared to failure closer to the tip 108 of the shaft.

[0118] In various embodiments, the first gradient braided region 958 extends into the thermal insulation region 105 of the shaft 104 (i.e., starting where the shaft connects to the handle 102 and ending in front of the expansion chamber 106). In various embodiments, the gradient braided portion 958 may have a first burst strength. The first burst strength may be constant along the thermal insulation region of the shaft. Alternatively, the first burst strength of the gradient braided portion 958 may increase from the base of the shaft to the expansion chamber. In various embodiments, the gradient braided portion 958 may have a first braid density. The first braid density may be constant along the thermal insulation region of the shaft. Alternatively, the first braid density of the gradient braided portion 958 may increase from the base of the shaft to the expansion chamber.

[0119] In some embodiments, the minimum burst strength of the braided section 958 may be 20.7 MPa, 13.8 MPa, 6.9 MPa, 5.5 MPa, 4.1 MPa, 2.8 MPa, 1.4 MPa, or 0.7 MPa or less, or within a range of any of these values. In some embodiments, the maximum burst strength of the braided section 958 may be 0.7 MPa, 2.0 MPa, 3.4 MPa, 4.8 MPa, 6.2 MPa, 6.9 MPa, 13.8 MPa, or 20.7 MPa or more, or within a range of any of these values.

[0120] In various embodiments, the second braided portion 960 extends into the expansion chamber 106 of the shaft 104. In some embodiments, the second braided portion 960 may begin at the starting end of the expansion chamber and terminate at or near the tip 108 of the shaft. Alternatively, the second braided portion 960 may begin toward the distal end of the insulating region 105 of the shaft (as shown in Figure 9) and terminate at or near the tip 108 of the shaft. In some embodiments, the second braided portion 960 is continuous with the first braided portion 958. Alternatively, the second braided portion 960 may be formed from elements physically separate from the elements of the first braided region 958.

[0121] In various embodiments, the second braided portion 960 may have a second burst strength. The second burst strength may be constant along the length of the first braided layer. Alternatively, the second burst strength of the second braided portion 960 may increase along the length of the first braided layer (from the end of the insulating region 105 to the tip 108). In various embodiments, the second braided portion 960 may have a second braid density. The second braid density may be constant along the length of the second braided portion. Alternatively, the second braid density of the second braided portion 960 may increase along the length of the second braided portion.

[0122] In some embodiments, the burst strength of the second braided portion 960 may be 10.3 MPa, 12.9 MPa, 15.5 MPa, 18.1 MPa, 20.7 MPa, or 41.4 MPa or more. In some embodiments, the burst strength of the second braided portion 960 may be 34.5 MPa, 31.0 MPa, 27.6 MPa, 24.1 MPa, or 20.7 MPa or less. In some embodiments, the burst strength of the second braided portion 960 may be in the range of 10.3 MPa to 34.5 MPa, in the range of 12.4 MPa to 31.0 MPa, in the range of 15.5 MPa to 27.6 MPa, in the range of 17.9 MPa to 34.5 MPa, or about 20.7 MPa.

[0123] In various embodiments, the third braided region 962 extends to the expansion chamber 106 of the shaft 104. In some embodiments, the third braided region 962 may start from the beginning of the expansion chamber and end at or near the tip 108 of the shaft.

[0124] In various embodiments, the third braided region 962 may have a third bursting strength. The third bursting strength may be constant along the length of the third braided region. Alternatively, the bursting strength of the third braided region 962 may increase along the length of the third braided region. In various embodiments, the third braided region 962 may have a third braid density. The third braid density may be constant along the length of the third braided region. Alternatively, the braid density of the third braided region 962 may increase along the length of the first braided layer.

[0125] In some embodiments, the burst strength of the third braided region 962 may be 10.3 MPa, 12.9 MPa, 15.5 MPa, 18.1 MPa, or 20.7 MPa or higher. In some embodiments, the burst strength of the third braided region 962 may be 34.5 MPa, 31.0 MPa, 27.6 MPa, 24.1 MPa, or 20.7 MPa or lower. In some embodiments, the burst strength of the third braided region 962 may be in the range of 10.3 MPa to 34.5 MPa, in the range of 12.4 MPa to 31.0 MPa, in the range of 15.5 MPa to 27.6 MPa, in the range of 17.9 MPa to 24.1 MPa, or about 20.7 MPa.

[0126] In alternative embodiments, any or all of the gradient braided regions 958, 960, 962 may be formed from a coil. A coil as defined herein is a filament material wound around a shaft. Similar to the braided materials described above, the filament may be selected to have one or more suitable materials and to have a cross-sectional shape such as circular, rectangular, or other shapes. Each region may contain a coil having different densities, radial strengths, stiffness, and flexibility. The coil may be single-layer or multi-layer. In some embodiments, multi-layer coils may have alternating winding directions (e.g., the first layer is wound clockwise and the second layer counterclockwise). In various embodiments, the coil pitch may be modified to optimize the shaft's properties such as flexibility and burst strength. For example, a denser coil pitch may increase the burst strength of the shaft, while a looser coil pitch may increase the shaft's flexibility. In various embodiments, the pitch of the coil material may increase from the base of the shaft 104 to the tip 108 of the shaft.

[0127] [Transitions between braided regions] In some embodiments, the transitions between the first, second, and third braided sections are density transitions of the same physical braided elements, such that one braided region is continuous with an adjacent braided region. Alternatively, one braided section may be made from elements that are physically separated from the elements of the adjacent braided region.

[0128] [Composite shaft (Figure 10)] Referring to Figure 10, schematic diagrams of some of the cryoablation shafts according to various embodiments of the present disclosure are shown. In various embodiments, the expansion chamber 106 of the shaft 104 includes a supply pipe 324 concentrically located within a composite return pipe 1064. In various embodiments, the return pipe may be a composite shaft. In various embodiments, the composite return pipe 1064 is formed from one or more distinct layers. One possible return pipe layer is the braided layer 1066 shown in Figure 10.

[0129] In various embodiments, the composite return tube 1064 may be formed from one or more polymer and / or braided layers, as described in detail herein. After forming the separate layers, the composite shaft may be heated to a temperature at which the separate layers bond to each other to form a single composite layer. In some embodiments, some of the separate layers may contribute to the radial strength of the expansion chamber, while others may contribute to the gas containment capacity of the expansion chamber. In such embodiments, radial strength and gas containment may be achieved from a single composite layer. Such a configuration can improve the tunability of the properties of the expansion chamber material while reducing the diameter of the expansion chamber.

[0130] In some embodiments, an additional braided layer 1066 may be placed on top of the rest of the composite return tube 1064. The additional braided layer is selected to have braided properties that increase the radial strength of the expansion chamber 106.

[0131] [Example of distal mounting (Figure 10)] In various embodiments, the working fluid can be contained in the tip 108 of the shaft using a plug 1068 and one or more joints 1070. In various embodiments, the joints 1070 and / or the plug 1068 may be formed of one or more materials suitable for coupling with the composite return tube 1064 and / or braided layer 1066 to enhance the sealing of the shaft 104. In various embodiments, the joints 1070 and / or the plug 1068 may be formed of one or more materials having sufficient strength to enhance the burst strength of the expansion chamber.

[0132] In various embodiments, the plug 1068 includes a raised portion 1072. The raised portion 1072 improves the mechanical strength of the joined joint 1070 by providing additional structural support to the joint to resist the pressure within the expansion chamber.

[0133] [Marker for imaging system] The joint 334 (Figure 3) and the distal tip 108 (Figures 8 and 10) are configured to appear on the imaging system. The joint 334 may include a marker band made of radiopaque material such as tungsten, platinum-iridium, or other suitable material. The material and dimensions of the distal tip 108 may be configured to appear on the imaging system. Examples of materials for the distal tip 108 include stainless steel and nitinol. Markers at each end of the device's operating area help the physician visually identify the location of the cryoablation operating area relative to the patient's anatomical structure and the target area of ​​cryoablation. Examples of imaging systems include ultrasound, fluoroscopy, cone-beam CT, and MRI systems.

[0134] [Installation Options] In some embodiments, the catheter system is delivered using a sheath introduction system. An example of a sheath introduction system is a maneuverable sheath. Alternatively, the catheter system may be maneuverable. In another embodiment, the catheter system includes a monorail lumen along a portion of the catheter to facilitate introduction.

[0135] [Guidewire delivery option] In various embodiments, the cryoablation system preferably includes a guidewire. A guidewire, as defined herein, is a flexible medical wire inserted into the body to guide a larger instrument, such as a catheter, to a target location. Using a guidewire in a cryoablation system allows for access to a flexible shaft with greater precision and less damage to parts of the patient's anatomical structure (e.g., the biliary system). The guidewire may extend within a guidewire lumen that extends over part or all of the length of the shaft. A guidewire lumen, as defined herein, is a channel or hollow space that facilitates the insertion of the guidewire. The guidewire lumen may be added to the cryoablation system in a monorail configuration or an over-the-wire configuration. In alternative embodiments, the cryoablation system may be introduced into the patient using a sheath instead of a guidewire.

[0136] In a monorail configuration, the guide wire and guide wire lumen extend only within a portion of the shaft's length. In the cryoablation system 100, the guide wire and guide wire lumen may extend only within the distal portion of the shaft 104 in a monorail configuration (for example, only within the portion adjacent to the tip 108, or only within the portion slightly away from the tip 108). In some embodiments, the distal tip 108 may include a lumen through which the guide wire passes. Compared to an over-the-wire configuration in which the guide wire lumen extends along the entire length of the shaft, the monorail configuration does not require the guide wire lumen to extend throughout the entire shaft, thus allowing for a smaller shaft diameter and reduced shaft complexity. In various embodiments, when using a monorail guide wire, most of the cross-section of the shaft 104 remains unchanged from the shaft embodiment shown in Figure 3.

[0137] In an over-the-wire configuration, an additional guidewire lumen is present and extends along the length of the shaft. In various embodiments, the lumen extends along the entire length of the shaft. Over-the-wire catheter configurations are particularly useful for positioning medical devices in parts of anatomical structures (e.g., the biliary system) that are difficult to navigate. Compared to monorail lumen configurations, over-the-wire catheter configurations reduce the possibility of uneven strain on parts of the catheter configuration during bending that occurs during the navigation and / or positioning of the shaft, thereby reducing the possibility of structural damage or failure of the catheter device. However, the external diameter size and complexity of the cryoablation shaft can increase due to the need to extend an additional lumen and guidewire within the shaft.

[0138] To illustrate the size difference between the monorail shaft and the over-the-wire shaft in a specific example, the outer diameter of the monorail shaft may be approximately 6–7 French (2.00–2.33 mm), while the outer diameter of the over-the-wire shaft may be approximately 8–9 French (2.67–3.00 mm). These ranges are for illustrative purposes only, but the over-the-wire shaft generally requires a diameter greater than or equal to the diameter of the monorail shaft. To implement an over-the-wire configuration, the shaft 104 of the cryoablation system needs to be modified to accommodate an additional guidewire lumen and guidewire. This can be done in any suitable way, but three possible embodiments are shown in Figures 11–13.

[0139] In each of the examples described below with respect to Figures 11 to 13, the external shape of each of the following elements of the cryoablation system, namely the feed tube, return tube, guidewire lumen, and adiabatic shaft, may be circular. In other words, these elements have a circular external shape in radial cross-section. In alternative embodiments, the external shapes of the feed tube, return tube, guidewire lumen, and / or adiabatic shaft may be any other suitable shape, such as elliptical, rectangular, or any other shape that facilitates placement within the body lumen.

[0140] In each of the examples described below with respect to Figures 11-13, the internal space defined by the guidewire lumen is circular and does not contain any components other than the guidewire during the introduction process. The guidewire may be removed from the guidewire lumen after the catheter has been introduced to the target body location. Alternatively, depending on the procedure being performed, the guidewire may remain inside the guidewire lumen during the cryoablation procedure. In each of the examples described below with respect to Figures 11-13, the supply tube is positioned concentrically (Figures 11 and 13) or eccentrically (Figure 12) within the return tube.

[0141] In each of the examples described below with respect to Figures 11 to 13, the internal space of the insulated shaft is occupied by other elements, and as a result, the internal space used by the vacuum insulated chamber is not circular and its shape differs from embodiment to embodiment. Furthermore, the internal space defined by the return pipe and supply pipe may also differ from embodiment to embodiment, as the internal space defined by these elements may be occupied by one or more of several other elements.

[0142] [Separated exhaust configuration (Figure 11)] Referring to Figure 11, cross-sectional views of cryoablation shafts according to various embodiments of the present disclosure are shown. In various embodiments, the shaft 104 may include a supply pipe 324, a return pipe 326, an insulated shaft 328, and a filament 330. The shaft also includes a guidewire lumen 1132 for inserting a guidewire, the guidewire lumen 1132 extending over the entire length of the shaft 104. In the example of Figure 11, the supply pipe 324 is coaxially located within the return pipe 326, and the guidewire lumen 1132 is in contact with the return pipe 326. The guidewire lumen 1132 and the return pipe 326 are each tangentially connected to the insulated shaft 328 by a support filament 330. The supply pipe 324, the return pipe 326, the guidewire lumen 1132, and the filament 330 are all surrounded by the insulated shaft 328. In alternative embodiments, the shaft may not include the filament 330.

[0143] In various embodiments, the high-pressure working fluid, after exiting the handle 102, travels distally down the shaft 104 through the supply pipe 324. The working fluid then cools and expands in the expansion chamber 106, and returns proximal through the shaft 104 in the annular space between the supply pipe 324 and the return pipe 326.

[0144] In the example in Figure 11, the supply pipe has a substantially circular cross-section and does not house any other elements. In the example in Figure 11, the supply pipe 324 is housed concentrically within the return pipe 326.

[0145] In the example shown in Figure 11, the return tube 326 and the guide wire lumen 1132 are arranged side by side adjacent to each other. The external shape of the return tube 326 when combined with the guide wire lumen 1132 resembles the shape of a figure eight.

[0146] A vacuum chamber space is defined between the outer wall of the return tube 326 and the guide wire lumen 1132 and the inner wall of the insulated shaft 328. The vacuum chamber space is circular in shape and does not include the figure-eight shaped internal space occupied by the guide wire lumen 1132 and the return tube 326.

[0147] The support filament 330 wraps around the outer surfaces of the supply tube 324 and the guide wire lumen 1132, holding these two components in a fixed relationship with each other. In an alternative embodiment, the shaft may not include the filament 330.

[0148] [Common exhaust configuration (Figure 12)] Referring to Figure 12, cross-sectional views of cryoablation shafts according to various embodiments of the present disclosure are shown. In various embodiments, the shaft may include a supply pipe 324, a return pipe 326, an insulated shaft 328, and a support filament 330. The shaft also includes a guidewire lumen 1132 for inserting a guidewire, the guidewire lumen 1132 extending over the entire length of the shaft 104. In the example of Figure 12, the return pipe 326 is coaxially located within the insulated shaft 328, and the filament 330 is located between the return pipe 326 and the insulated shaft 328. Both the supply pipe 324 and the guidewire lumen 1132 are located within the return pipe 326. In alternative embodiments, the shaft may not include the filament 330.

[0149] In various embodiments, the high-pressure working fluid, after exiting the handle, travels distally down the shaft 104 through the supply pipe. The working fluid then cools and expands in the expansion chamber 106 and returns proximal through the shaft 104 in the space between the supply pipe 324 and the return pipe 326. As seen in the example in Figure 12, a guidewire lumen 1132 is also located in the space between the supply pipe 324 and the return pipe 326. Thus, the return passage for the working fluid is defined by the cross-sectional area of ​​the return pipe 326 minus the cross-sectional area of ​​the guidewire lumen 1132 and the cross-sectional area of ​​the supply pipe 324.

[0150] In the example shown in Figure 12, both the supply pipe 324 and the guidewire lumen 1132 have a circular cross-section and do not house any other components. The supply pipe 324 and the guidewire lumen 1132 are located side by side. In some embodiments, the supply pipe 324 and the guidewire lumen 1132 are adjacent to each other.

[0151] In the example shown in Figure 12, both the supply pipe 324 and the guidewire lumen 1132 are located within the return pipe 326. The return pipe 326 defines a space for the working gas to return, and this space has a circular outer shape. The inner shape of the return pipe 326 is defined around the circular outer shapes of the supply pipe 324 and the guidewire lumen 1132.

[0152] The supply tube 324 and the guide wire lumen 1132 are arranged side by side. There may or may not be a gap between the supply tube 324 and the guide wire lumen 1132. In various embodiments, the supply tube 324 and the guide wire lumen 1132 are adjacent to each other, and the outer shape of the supply tube 324 combined with the guide wire lumen 1132 resembles a figure eight shape.

[0153] The working gas return space within the return pipe 326 is defined between the outer walls of the supply pipe 324 and the guide wire lumen 1132 and the inner wall of the return pipe 326. The working gas return space is defined around the internal space that may be occupied by the guide wire lumen 1132 and the supply pipe 324 and has a circular outer shape.

[0154] The return pipe 326 is coaxially located within the adiabatic shaft 328. The vacuum chamber space is annular between the inner wall of the adiabatic shaft and the outer wall of the return pipe. [Central guidewire lumen configuration (Figure 13)] Referring to Figure 13, cross-sectional views of cryoablation shafts according to various embodiments of the present disclosure are shown. In various embodiments, the shaft 104 may include a guidewire lumen 1132 coaxially located within a supply pipe 324. The supply pipe 324 is coaxially located within a return pipe 326. The return pipe 326 is coaxially located within an insulated shaft 328. The filament 330 is located between the return pipe and the insulated shaft. In alternative embodiments, the shaft may not include the filament 330.

[0155] In various embodiments, the high-pressure working fluid, after exiting the handle 102, travels distally down the shaft 104 through the supply pipe 324. Since the guidewire lumen 1132 is coaxially located within the supply pipe 324, the working gas fluid travels down the annular space between the return pipe 326 and the guidewire lumen 1132. The working fluid then cools and expands in the expansion chamber 106, and then returns proximal through the shaft 104 within the annular space between the supply pipe 324 and the return pipe 326.

[0156] In the example shown in Figure 13, the supply pipe 324 is coaxially located within the return pipe 326. The return pipe 326 is coaxially located within the adiabatic shaft 328. The vacuum chamber space is annular between the inner wall of the adiabatic shaft and the outer wall of the return pipe.

[0157] [Guide wire lumen configuration (Figure 14)] Referring to Figure 14, cross-sectional views of guidewire lumens according to various embodiments of the present disclosure are shown. In various embodiments, the guidewire lumen 1132 is configured to extend over the length of the cryoablation shaft 104 when inserted into the cryoablation shaft. In various embodiments, the guidewire lumen 1132 is configured for guidewire insertion. In various embodiments, the guidewire lumen 1132 may include a metal tube 1432 and a polymer sleeve 1442 configured to surround at least a portion of the metal tube.

[0158] In various embodiments, the guidewire lumen 1132 may include a metal tube 1432. The metal tube may be formed from any suitable material such as Nitinol or stainless steel. In various embodiments, at least a portion of the metal tube 1432 may include one or more slots 1434. The slots 1434 may be formed in the tube material by any suitable means such as laser cutting. The slots 1434 may be laser-cut into the metal tube 1432 using any suitable pattern to optimize the strength and flexibility of the metal tube 1432. Many different configurations and patterns of slots 1434 are available and may be selected to have the desired flexibility for their application.

[0159] In some embodiments, the metal tube 1432 may include a plurality of slots 1434 along its entire length. In some embodiments, the metal tube 1432 may define a plurality of slots 1434 along its length between portions of the metal tube 1432 that do not have slots. For example, the metal tube 1432 may not have slots 1434 in its distal end portion 1443. In various embodiments, the metal tube 1432 may not have slots 1434 in its proximal end portion 1445. In various embodiments, the metal tube 1432 may not have slots 1434 in both its distal end portion 1443 and its proximal end portion 1445.

[0160] The metal tube 1432 may be configured to have sufficient flexibility to form a curve with a desired radius of curvature. For example, the metal tube 1432 may have sufficient flexibility to allow the guidewire lumen 1132 to form a curve with a minimum radius of curvature of 30 mm, 20 mm, 10 mm, 5 mm, or 3 mm or less. The flexibility of the metal tube 1432 allows the entire cryoablation shaft to have flexibility that enables maneuverability toward the treatment site.

[0161] In various embodiments, the guidewire lumen 1132 may include a polymer sleeve 1442. The polymer sleeve 1442 may be formed from any suitable material such as polyether block amide or polyethylene terephthalate. In various embodiments, the polymer sleeve 1442 is configured to cover at least a portion of the metal tube 1432. In the example of Figure 14, at least a portion of the metal tube 1432 includes a plurality of slots 1434, and the polymer sleeve 1442 is configured to form a seal around the slot-forming portion of the metal tube 1432. In such embodiments, the polymer sleeve 1442 is configured to provide an airtight seal around the metal tube 1432, preventing gas from entering the metal tube through the slots while maintaining the flexibility of the metal tube.

[0162] In various embodiments, the polymer sleeve 1442 covers the entire length of the metal tube 1432. Alternatively, as shown in Figure 14, for example, the polymer sleeve 1442 does not cover the metal tube 1432 at the distal end portion 1443. In various embodiments, the polymer sleeve 1442 does not cover the metal tube 1432 at the proximal end portion 1445. In various embodiments, the polymer sleeve 1442 does not cover the metal tube 1432 at both the distal end portion 1443 and the proximal end portion 1445. In various embodiments, the polymer sleeve 1442 extends along the length of the metal tube 1432 between the distal end portion 1443 and the proximal end portion 1445. The exposed portions of the metal tube 1432 at the distal end, proximal end, or both ends provide a metal surface for joining other components and achieving an hermetically sealed bond.

[0163] In various embodiments, the guidewire lumen 1132 may include a first compression wrap portion 1440 configured to seal the polymer sleeve 1442 to the metal tube 1432 at the distal end of the polymer sleeve 1442. In various embodiments, the guidewire lumen 1132 may include a second compression wrap portion 1441 configured to seal the polymer sleeve 1442 to the metal tube 1432 at the proximal end of the polymer sleeve 1442. In the example of Figure 14, the polymer sleeve 1442 is sealed to the metal tube 1432 such that the distal end portion 1443 and the proximal end portion 1445 of the metal tube 1432 are not covered by the polymer sleeve or compression wrap portion.

[0164] In various embodiments, the first compression winding section 1440 and the second compression winding section 1441 are configured to seal the polymer sleeve to the metal tube 1432 by applying a consistent compressive force around the polymer sleeve 1442.

[0165] In various embodiments, the first compression winding section 1440 and the second compression winding section 1441 include a filament wound around the polymer sleeve 1442 and metal tube 1432 of the guidewire lumen 1132. In various embodiments, the filament is configured to be wound around the polymer sleeve 1442 and metal tube 1432 of the guidewire lumen 1132 at a winding threshold tension. For example, the filament needs to be able to withstand the suspension of an object of a predetermined mass without breaking. The predetermined mass may be 0.5 kg, 1 kg, 1.5 kg, or more. In some embodiments, the filament is suspended at the predetermined mass during the winding process to apply sufficient winding tension.

[0166] In various embodiments, the compression winding portion may have a certain tensile strength. In some embodiments, the tensile strength may be 1.0 gigapascals (GPa), 1.8 GPa, 2.7 GPa, or 3.5 GPa or more. In some embodiments, the tensile strength may be 6.0 GPa, 5.2 GPa, 4.3 GPa, or 3.5 GPa or less. In some embodiments, the tensile strength may be in the range of 1.0 GPa to 6.0 GPa, in the range of 1.8 GPa to 5.2 GPa, in the range of 2.7 GPa to 4.3 GPa, or about 3.5 GPa.

[0167] In various embodiments, the compression winding portion may be a single filament, a multi-filament material, a single-wire material, a multi-wire material, a metal, a plastic, or a composite material. In various embodiments, the compression winding portion is configured to maintain tension to the end of the winding portion. In various embodiments, the compression winding portions 1440, 1441 may be formed from single-filament sutures and / or multi-strand sutures. In various embodiments, the compression winding portion may be formed from one or more materials, including but not limited to fibrous materials such as stainless steel, tungsten, platinum-iridium alloy (Pt-Ir), and fiber-based materials (e.g., Technora®, Dektran).

[0168] In various embodiments, the compression winding section may have a closed pitch (each winding of the filament is in contact with an adjacent winding). Alternatively, the compression winding section may have a pitch of 0.5 mm, 1.0 mm, 1.5 mm, or 2.0 mm or more, or a value within a range of any of these.

[0169] In some embodiments where the compression winding portion is a filament, the diameter of the filament may vary depending on the material of the filament and its ability to maintain tension during manufacturing. In some embodiments, the diameter of the filament may be 0.002 mm, 0.004 mm, or 0.005 mm or more. In some embodiments, the diameter of the filament may be 0.007 mm, 0.006 mm, or 0.005 mm or less. In some embodiments, the diameter of the filament may be in the range of 0.002 mm to 0.007 mm, in the range of 0.004 mm to 0.006 mm, or about 0.005 mm.

[0170] In various embodiments, the first compression winding section 1440 and the second compression winding section 1441 may include an adhesive configured to encapsulate the compression winding section. This adhesive is configured to maintain a winding threshold tension and can improve the material properties of the compression winding section, such as biocompatibility and radiopaqueness. Alternatively, the adhesive may be applied to individual parts of the compression winding sections 1440, 1441, such as the ends. Examples of suitable adhesives that can be used to encapsulate the compression winding section include cyanoacrylate adhesives and LOCTITE® adhesive, available from Henkel Adhesive Technologies, Inc., Bridgewater, New Jersey, USA.

[0171] In various embodiments, the filaments of the first compression winding section 1440 may be formed of a material configured to transmit electrical signals (e.g., conductive wire). In such embodiments, one or more sensors may be positioned at the distal end of the shaft 104 so that sensor data can be transmitted from the sensors to the console via the conductive filaments. In one example, an electromagnetic position sensor may be included at the distal tip 1436 of the shaft 104 so as to assist a physician in positioning the shaft within the patient's anatomical structure. In such a configuration, the first compression winding section 1440 may be configured to transmit a low voltage which is translated from the distal tip 1436 to the console. In another example, the first compression winding section 1440 may incorporate an optical fiber cable configured to provide information about the shape of a target anatomical structure. Any other suitable sensors or combinations of sensors, including but not limited to temperature sensors, pressure sensors, strain sensors, etc., may be included at the distal end of the shaft.

[0172] In various embodiments, the filaments of the first compression winding section 1440 may be formed from one or more high-resistance wires. The high-resistance wires may be configured to allow electric heating of the expansion chamber 106 of the shaft 104. Electric heating can facilitate a faster thawing of the ice ball. This can shorten the time required for the cryoablation procedure and reduce the possibility of pathway dissemination, where harmful tissue adheres to the shaft and spreads to other parts of the patient's anatomical structure.

[0173] In various embodiments, the guidewire lumen 1132 is configured to seal the distal tip 1436 of the cryoablation shaft 104. In various embodiments, the distal tip 1436 is configured to seal the distal end of the expansion chamber 106 of the cryoablation shaft 104. The distal tip 1436 may be formed from any suitable material such as nitinol or stainless steel.

[0174] In various embodiments, the distal end portion 1443 of the metal tube 1432 is joined to the proximal end of the distal tip portion 1436 using an intermetallic joining process such as welding, soldering, or brazing. In the example shown in Figure 14, the distal end portion 1443 of the metal tube does not have a slot 1434 and is not covered by a polymer sleeve 1442. Such embodiments allow the distal end portion 1443 of the metal tube 1432 to form a strong intermetallic joint 1438 with the distal tip portion 1436.

[0175] In various embodiments, the distal tip 1436 defines a central channel 1437, which is configured to receive a guidewire. In various embodiments, the proximal end of the central channel 1437 of the distal tip 1436 can be joined to the distal end portion 1443 of the metal tube 1432 to form an intermetallic joint 1438.

[0176] In various embodiments, the proximal end portion 1445 of the metal tube 1432 can be joined to the cryoablation probe at any suitable location, such as the proximal end of the shaft 104 or the handle 102.

[0177] In various embodiments, the guidewire lumen 1132 is constructed to be sufficiently robust so as not to be compressed by the high-pressure gas flow within the refrigeration ablation shaft 104. In various embodiments, the guidewire lumen 1132 is constructed to withstand the compression pressure during normal operation of the refrigeration ablation system, which is approximately 1 MPa or 150 psi. In various embodiments, the burst strength of the guidewire lumen 1132 may be 0.4 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, or 1.0 MPa or higher.

[0178] In various embodiments, the guidewire lumen 1132 is constructed to be sufficiently robust to withstand large compressive pressures of approximately 15 MPa or 2200 psi that may occur in the failure state of the refrigeration ablation system. In some embodiments, the burst strength of the guidewire lumen 1132 may be 9.0 MPa, 10.5 MPa, 12.0 MPa, 13.5 MPa, or 15.0 MPa or higher. In some embodiments, the burst strength may be 21.0 MPa, 19.5 MPa, 18.0 MPa, 16.5 MPa, or 15.0 MPa or lower. In some embodiments, the burst strength may be in the range of 9.0 MPa to 21.0 MPa, in the range of 10.5 MPa to 19.5 MPa, in the range of 12.0 MPa to 18.0 MPa, in the range of 13.5 MPa to 16.5 MPa, or approximately 15.0 MPa.

[0179] [An embodiment of a central guidewire lumen with a distal tip (Figure 15)] Referring to Figure 15, schematic diagrams of a portion of the guidewire lumen and distal tip in a cryoablation shaft according to various embodiments of the present disclosure are shown. In the example of Figure 15, the shaft has the central guidewire lumen configuration shown and described in Figure 13. Alternatively, the guidewire configuration options described with respect to Figure 14 can be used in the separate exhaust embodiment of Figure 11 or the common exhaust embodiment of Figure 12.

[0180] Referring again to Figure 15, in various embodiments, the shaft 104 may include a guide wire lumen 1132 that is coaxially located within the supply pipe 324. The supply pipe 324 is coaxially located within the return pipe 326, and at least a portion of the return pipe is coaxially located within the insulated shaft 328.

[0181] In various embodiments, the high-pressure working fluid flows down the supply pipe 324 after exiting the handle 102. The high-pressure working fluid undergoes expansion in or downstream of the Joule-Thomson orifice 332 and can return through the shaft in the annular space between the supply pipe 324 and the return pipe 326.

[0182] In various embodiments, the guidewire lumen 1132 is configured to be joined to the distal tip 1436 and then inserted into the distal end of the shaft 104. In various embodiments, the outer circumference 1554 of the distal tip 1436 is configured to be joined to the inner surface of the distal end of the return tube 326. In various embodiments, the inner surface of the return tube 326 is metal. The distal tip 1436 can be joined to the return tube 326 by any suitable means, such as an intermetallic bonding process, adhesive, or compression element, depending on the material of the innermost layer of the return tube.

[0183] In various embodiments, the outer diameter of the distal tip 1436 is configured to be substantially equal to the inner diameter of the return tube 326. In such embodiments, the guidewire lumen 1132 is configured to be centered within the shaft 104 by coupling the distal tip 1436 to the inner surface of the return tube 326.

[0184] In various embodiments, the outer surface of the distal tip 1436 includes projections, fins, bevels, shoulders, or two or more of these structures to improve the mechanical strength of the connection between the distal tip and the return tube 326 and to resist the pressure within the expansion chamber. Examples of such outer surface structures of the distal tip 1436, as well as structures and methods for securing the distal tip 1436 to the return tube 326, are shown and described in U.S. Patent Application No. 18 / 671,742, filed on 22 May 2024, entitled “Distal Tip Structure for Cryoablation Probe,” which is incorporated herein by reference in its entirety.

[0185] The concepts described herein may be applied to and used in connection with the cryoablation systems and components described in the following four U.S. Patent Applications filed on May 22, 2024: U.S. Patent Application No. 18 / 671,489, entitled "Cryoablation Catheter Shaft Construction"; U.S. Patent Application No. 18 / 671,627, entitled "Safety Devices for Cryoablation Probe"; U.S. Patent Application No. 18 / 671,677, entitled "Multiple Gas Circuit Connector and Method for Cryoablation System"; and U.S. Patent Application No. 18 / 671,742, entitled "Distal Tip Structure for Cryoablation Probe," which are incorporated herein by reference in their entirety.

[0186] As used herein and in the claims, “a / an” and “the” include multiple subjects unless otherwise explicitly indicated. The term “or” is generally used to include “and / or” unless otherwise explicitly indicated.

[0187] As used herein and in the claims, the term “configured” describes a system, apparatus, or other structure that is built or configured to perform a particular process or employ a particular configuration. The term “configured” may also be used interchangeably with other similar terms such as arranged and configured, built and positioned, constructed, manufactured and positioned.

[0188] All publications and patent applications referred to herein represent the level of skill of those skilled in the art to which the present invention pertains. All publications and patent applications are incorporated herein by reference to the same extent as if each individual publication or patent application were specifically and individually indicated by reference.

[0189] As used herein, an enumeration of numerical ranges by endpoints includes all numbers contained within that range (for example, 2 to 8 includes 2.1, 2.8, 5.3, 7, etc.). The headings used herein are for structural reference only. These headings should not be considered to limit or characterize any invention described in any claim that may arise from this disclosure. For example, with respect to the heading "Technical Field," the claims should not be limited by the language selected under that heading to describe that technical field. Similarly, the description of the technology in "Background Art" does not constitute prior art to any invention in this disclosure. Furthermore, the "Summary of the Invention" should not be considered as a characteristic of the invention described in the claims.

[0190] The embodiments described herein are not intended to be exhaustive, nor are they intended to limit the invention to the exact forms disclosed in the detailed description. Rather, the embodiments are selected and described so that those skilled in the art can recognize and understand the principles and practices. Several aspects have been described above with reference to various specific preferred embodiments and techniques. However, many changes and modifications can be made that fall within the spirit and scope of this disclosure.

Claims

1. It is a cryoablation shaft, Working fluid circuit and Vacuum circuits and, An insulating portion, wherein the vacuum circuit extends within the insulating portion, An expansion chamber extending distal to the aforementioned heat insulating portion, A guidewire lumen configured for guidewire insertion and extending over the length of the cryoablation shaft, Metal pipe and A polymer sleeve configured to surround at least a portion of the metal tube, The guide wire lumen includes, A supply pipe having a distal outlet within the expansion chamber, wherein the fluid from the working fluid circuit moves distally down the cryoablation shaft through the supply pipe and expands within the expansion chamber, A return pipe surrounding the supply pipe, The insulated shaft surrounding the aforementioned return pipe, A cryogenic ablation shaft equipped with a refrigeration ablation shaft.

2. The cryoablation shaft according to claim 1, wherein the guide wire lumen is coaxially located within the supply pipe, the supply pipe is coaxially located within the return pipe, and at least a portion of the return pipe is coaxially located within the adiabatic shaft.

3. The cryoablation shaft according to claim 2, wherein the fluid from the working fluid circuit moves distally down the cryoablation shaft through an annular space defined between the return pipe and the guide wire lumen.

4. The cryoablation shaft according to claim 1, wherein the metal tube comprises either nitinol or stainless steel.

5. The cryoablation shaft according to claim 1, wherein the polymer sleeve comprises either polyether block amide or polyethylene terephthalate.

6. The cryoablation shaft according to claim 1, wherein at least a portion of the metal tube includes a plurality of slots, and the polymer sleeve is configured to form a seal around the portion of the metal tube including the plurality of slots.

7. The cryoablation shaft according to claim 1, wherein the distal end of the expansion chamber is configured to be sealed to the distal tip of the cryoablation shaft, and the distal tip further comprises a metal.

8. The cryoablation shaft according to claim 7, wherein the distal end of the metal tube is joined to the proximal end of the distal tip using an intermetallic bonding process.

9. The cryoablation shaft according to claim 7, wherein the distal tip defines a central channel, the central channel is configured to receive the guidewire, and the proximal end of the central channel of the distal tip is joined to the distal end of the metal tube.

10. The cryoablation shaft according to claim 1, further comprising a first compression winding portion configured to seal the polymer sleeve to the metal tube at the distal end of the polymer sleeve.

11. The cryoablation shaft according to claim 10, further comprising a second compression winding portion configured to seal the polymer sleeve to the metal tube at the proximal end of the polymer sleeve.

12. The cryoablation shaft according to claim 1, wherein the guide wire lumen is capable of forming a curve having a minimum radius of curvature of 30 mm or less.

13. The guide wire lumen of the cryoablation shaft, A metal tube, wherein at least a portion of the metal tube includes a plurality of slots, A polymer sleeve configured to form a seal around the portion of the metal tube including the plurality of slots, It comprises a distal tip and, The guide wire lumen is configured to extend over the length of the cryoablation shaft, The aforementioned guidewire lumen is configured for guidewire insertion, The metal tube is configured to be joined to the distal tip of the cryoablation shaft using an intermetallic bonding process at the distal end of the cryoablation shaft, forming a guidewire lumen.

14. The guide wire lumen according to claim 13, wherein the guide wire lumen is coaxially located within the supply pipe of the cryoablation shaft, the supply pipe is coaxially located within the return pipe of the cryoablation shaft, and at least a portion of the return pipe is coaxially located within the insulated shaft of the cryoablation shaft.

15. The guidewire lumen according to claim 13, wherein the metal tube comprises either nitinol or stainless steel.

16. The guidewire lumen according to claim 13, wherein the polymer sleeve comprises either polyether block amide or polyethylene terephthalate.

17. The guidewire lumen according to claim 13, further comprising a compression winding portion configured to seal the polymer sleeve onto the metal tube.

18. The guide wire lumen according to claim 13, wherein the guide wire lumen is capable of forming a curve having a minimum radius of curvature of 30 mm or less.

19. It is a cryoablation shaft, Working fluid circuit and Vacuum circuits and, An insulating portion, wherein the vacuum circuit extends within the insulating portion, Expansion chamber and A guidewire lumen configured for guidewire insertion and extending over the length of the cryoablation shaft, A metal tube, wherein at least a portion of the metal tube includes a plurality of slots, A polymer sleeve configured to surround at least a portion of the metal tube and to form a seal around the portion of the metal tube including the plurality of slots, The guide wire lumen includes, A supply pipe having a distal outlet within the expansion chamber, wherein the fluid from the working fluid circuit moves distally down the cryoablation shaft through the supply pipe and expands within the expansion chamber, A return pipe surrounding the supply pipe, The system comprises an insulating shaft surrounding the return pipe, A cryoablation shaft wherein the guide wire lumen is coaxially located within the supply pipe, the supply pipe is coaxially located within the return pipe, and the return pipe is coaxially located within the adiabatic shaft.

20. The cryoablation shaft according to claim 19, wherein the distal end of the expansion chamber is configured to be sealed to the distal tip of the cryoablation shaft, and the distal tip further comprises a metal.

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