Methods and systems for treating venous disease

Abstract

The technology allows for electrical connection between a single heated segment treatment catheter and an energy delivery controller. The catheter and controller are connected using a tip-sleeve, tip-ring-sleeve, tip-ring-ring-sleeve, tip-ring-ring-ring-sleeve, or other suitably configured push-fit or blind-fit configuration. The catheter may have multiple individually selectable segments or a single segment and is also connected to an energy controller and a suitable push-fit connection device that is recognized and differentiated by different energy delivery profiles. The catheter can deliver heat-based therapy to a patient's perforator veins.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 015,416, entitled "METHODS AND SYSTEMS FOR VENOUS DISEASE TREATMENT," filed April 24, 2020, which is incorporated by reference in its entirety. Incorporation by Reference

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

[0002]

[0003] The present disclosure details novel systems and methods for treating a patient's vasculature, and in particular, for treating a patient's perforator veins (PV). [Background technology]

[0003]

[0004] Blood vessels and other physiological structures may fail to perform their proper functions. For example, if opposing valve leaflets in a vein do not touch each other, blood flow in the vein is not necessarily restricted primarily to one direction toward the heart. This condition is called venous reflux, which causes a local increase in blood pressure in the vein. The local increase in blood pressure is then transmitted to surrounding tissues and the skin. Furthermore, failure of a valve in a vein causes a cascade of successive failures of valves along the vein. To standardize the reporting and treatment of the diverse symptoms of chronic venous disorders, a comprehensive clinical-etiology-anatomy-pathophysiology (CEAP) classification system has been developed to enable uniform diagnosis. The CEAP classification is commonly used to describe levels of patient symptoms of increasing severity, from spider veins, to varicose veins, to swelling (edema), to skin changes (bluish blotches, lipodermatosclerosis), to previously healed ulcers, and finally, to active ulcers, which are considered the most severe. Chronic venous insufficiency is a term often used to describe the more severe symptoms of chronic peripheral venous disease.

[0004]

[0005] The veins of the human lower extremity consist of three systems: the superficial venous system, the deep venous system, and the perforating venous system, which connects the superficial and deep systems. The superficial system includes, among others, the great saphenous vein (GSV) and the small saphenous vein (SSV). The deep venous system includes the anterior and posterior tibial veins, which together form the popliteal vein, which becomes the femoral vein when joined by the small saphenous vein.

[0005]

[0006] Perforator veins connect the deep venous system of the legs to the superficial veins closer to the skin. Normal or healthy perforator veins pass blood from the superficial veins to the deep veins as part of normal blood circulation. Dysfunctioning perforator veins allow blood flow from the deep venous system to the superficial veins, causing or contributing to problems such as varicose veins, edema, skin and soft tissue changes, lipodermatosclerosis, chronic cellulite, venous ulcers, and the like.

[0006]

[0007] Several procedures have been proposed for the isolation of incompetent perforator veins. The "Linton" procedure requires a very long incision (knee to ankle) over the mid-calf to expose the perforator veins. Individual veins are then surgically dissected, ligated, and severed to prevent blood flow between the superficial and deep venous systems. A minimally invasive alternative has been developed by DePalma, in which individual incompetent perforator veins are identified along "Linton's lines" using ultrasound. Small incisions are then used to access individual perforators for ligation and dissection. More recently, individual ligation and dissection of perforator veins has been performed using an endoscope inserted into the proximal calf. Summary of the Invention [Problem to be solved by the invention]

[0007]

[0008] While generally effective, each of the above procedures requires surgical incision followed by ligation and sectioning of the vein. Thus, at best, the procedures are traumatic for the patient and require significant operating time. Furthermore, the procedures are complex and often require a second surgeon to assist with the procedure.

[0008]

[0009] For these reasons, it would be desirable to provide additional and improved techniques for blocking dysfunctional perforator veins for the treatment of varicose veins, edema, skin and soft tissue changes, lipodermatosclerosis, chronic cellulite, venous ulcers, and other conditions. Such procedures should preferably be minimally invasive, relying, for example, on introducer sheaths, cannulas, catheters, trocars, or needles to gain access to the perforator veins at the deep fascial plane. In particular, it would be desirable if a procedure requiring little or no incision could be performed under local anesthesia, reducing postoperative healing time and morbidity and complication rates, and requiring only a single surgeon. Additionally, it would be desirable to provide devices and methods useful for performing procedures on other tissues and hollow anatomical structures in addition to perforator veins. At least some of these objectives are met by the various embodiments of the present invention described herein below. [Means for solving the problem]

[0009]

[0056] A system is provided comprising: a heating catheter including a handle and a heating element formed from a resistive coil positioned at the distal end of the heating catheter; an energy delivery control device having a display and a socket for receiving a TRS connector; and an interconnecting cable extending between the handle of the catheter and the TRS-type connector at the end of the interconnecting cable, the TRS connector being configured to be received in the socket of the energy delivery control device, the interconnecting cable including a power delivery line, a communication line, and a shared ground wire providing a return path for the power delivery line and the communication line to the energy delivery control device, the power delivery line and the communication line terminating in the TRS-type connector.

[0010]

[0057] In some embodiments, the system includes a thermocouple within the heating element and in electrical contact with the TRS-type connector.

[0058] In another embodiment, the system includes a push button on the handle.

[0011]

[0059] In some embodiments, the TRS style connector is a tip-sleeve, tip-ring-sleeve, tip-ring-ring-sleeve, tip-ring-ring-ring-sleeve, or other suitably configured push-fit or blind-fit configuration.

[0012]

[0060] In some embodiments, the heating element comprises a generally helically shaped resistive heater coil disposed near the distal end of the shaft.

[0061] In other embodiments, the thermocouple is positioned on, in, or within the heater coil or the segment of the catheter that includes the heater coil.

[0013]

[0062] In one embodiment, the system further includes an insulating coating covering the heating element.

[0063] In some embodiments, the heating catheter is flexible or has a rigid section and a flexible section.

[0014]

[0064] In many embodiments, the heating catheter has an insertable length of 40 cm.

[0065] A method of delivering heat-based therapy to a patient's perforator veins is provided, the method including: coupling a heating catheter having a single 5 mm long heating element formed from a resistive coil positioned at the distal-most end of the catheter to an energy delivery controller using a TRS connector associated with the heating catheter; preparing the energy delivery controller for delivery of thermal energy using the heating catheter by automatically recognizing the catheter as having a single 5 mm long resistive heating element; accessing the patient's vasculature using a needle and cannula assembly; introducing the heating catheter into the patient's vasculature to an initial treatment site; initiating a single heating segment heat delivery profile in the energy delivery controller by depressing a button on the catheter handle; and providing heat therapy at the initial treatment site according to the single heating segment heat delivery profile while an energy generating device monitors the output of a thermocouple associated with the heating element to a 130°C setpoint.

[0015]

[0066] In some embodiments, the initial treatment site is a perforator vein at or below the fascial layer.

[0067] In another embodiment, pressing the button initiates the delivery of a single 20 second heat treatment of a single heating segment heat delivery profile.

[0016]

[0068] In one embodiment, the method further includes advancing a needle and cannula assembly into the blood vessel above the fascial layer, and advancing a heating segment through the cannula to a treatment site at or below the fascial layer.

[0017]

[0069] In some embodiments, the method includes advancing a needle and cannula assembly into a blood vessel at or below the fascial layer, and advancing a probe through the cannula to a treatment site at or below the fascial layer.

[0018]

[0070] In some embodiments, the method includes monitoring the temperature at the treatment site and modulating power delivery to the energy element in response to the monitored temperature.

[0019]

[0071] In another embodiment, the method includes initiating multiple thermal treatments within the perforator veins at multiple segments from the initial treatment site at or below, across, and above the fascia.

[0020]

[0072] In one embodiment, the step of monitoring the temperature is performed using a thermocouple on, in, or within the heating element.

[0073] Also provided is a method of treating a blood vessel at a treatment site, the method including the steps of using an energy-emitting probe, the probe comprising an elongate shaft having a proximal end and a distal end, and an energy element adjacent the distal end, the energy element comprising a generally helical-shaped resistive heater coil disposed near the distal end of the elongate shaft; accessing the blood vessel through the skin with a needle and cannula assembly; removing the needle from the cannula; advancing the energy-emitting probe through the cannula to the treatment site; applying energy to the treatment site with the energy element to constrict the blood vessel, wherein the energy is applied intravascularly to the blood vessel; and removing the probe and cannula.

[0021]

[0074] In some embodiments, the method includes advancing a needle and cannula assembly into a blood vessel above the fascial layer, and advancing a probe through the cannula to a treatment site at or below the fascial layer.

[0022]

[0075] In one embodiment, the method includes monitoring the temperature at the treatment site and modulating power delivery to the energy element in response to the temperature.

[0076] In some embodiments, the blood vessel comprises a perforator vein.

[0023]

[0077] In another embodiment, the probe shaft is flexible.

[0078] One embodiment includes a TRS connector at the proximal end of the elongate shaft.

[0079] In some embodiments, the method includes advancing a needle and cannula assembly into a blood vessel at or below the fascial layer, and advancing a probe through the cannula to a treatment site at or below the fascial layer.

[0024]

[0080] A method of treating a blood vessel at a treatment site is provided, the method including the steps of using an energy-emitting probe, the probe including an elongate shaft having a proximal end and a distal end, and an energy element adjacent the distal end, the energy element including a generally helically shaped resistive heater coil segment disposed near the distal end of the shaft, the helically shaped resistive heater coil segment including the energy element having an insulating coating; accessing the blood vessel through the skin with a needle and cannula assembly; removing the needle from the cannula; advancing the energy-emitting probe through the cannula to the treatment site; applying energy to the treatment site using the energy element to constrict the blood vessel, the energy being applied intravascularly to the blood vessel; and removing the probe and cannula.

[0025]

[0081] In some embodiments, the method includes advancing a needle and cannula assembly into a blood vessel above the fascial layer, and advancing a probe through the cannula to a treatment site at or below the fascial layer.

[0026]

[0082] In one embodiment, the method includes monitoring the temperature at the treatment site and modulating power delivery to the energy element in response to the temperature.

[0083] In one embodiment, the blood vessel comprises a perforator vein.

[0027]

[0084] In another embodiment, the probe shaft is flexible.

[0085] In some embodiments, the method further includes a TRS connector at the proximal end of the elongate shaft.

[0028]

[0086] In some embodiments, the method includes advancing a needle and cannula assembly into a blood vessel at or below the fascial layer, and advancing a probe through the cannula to a treatment site at or below the fascial layer.

[0029]

[0087] In one embodiment, the method further comprises a foot switch in communication with the energy delivery control device, and initiation of the therapy delivery sequence is initiated by user interaction with the energy delivery control device using a push button on the handle or the foot switch.

[0030]

[0088] There is provided a heating catheter comprising: a handle; a flexible shaft extending from the handle, the flexible shaft having an insertable length of up to 40 cm; a heating element formed with a resistive coil positioned in a distal portion of the shaft; a plurality of leads connected to the heating element; and an energy delivery control device having a socket configured to receive a connector of the heating catheter, wherein the energy delivery control device is configured to apply current to the first lead and the second lead to activate a first heating length of the heating element, to apply current to the first lead and the third lead to activate a second heating length of the heating element, and to apply current to the first lead and the fourth lead to activate a third heating length of the heating element.

[0031]

[0089] In some embodiments, the connector of the heating catheter comprises a TRS-type connector, and the catheter further comprises an interconnecting cable extending between the handle of the catheter and the TRS-type connector, the TRS connector configured to be received in a socket of the energy delivery control device, the interconnecting cable including power delivery lines, communication lines, and a shared ground wire providing a return path for the power delivery lines and communication lines to the energy delivery control device, and the power delivery lines and communication lines terminating within the TRS-type connector.

[0032]

[0090] In some embodiments, the catheter includes a thermocouple within the heating element.

[0091] In some embodiments, the thermocouple is positioned between the first lead and the second lead.

[0033]

[0092] In other embodiments, the thermocouple is galvanically isolated from the circuitry configured to power the heating element.

[0093] In some embodiments, the thermocouple and the heating element do not share a common ground.

[0034]

[0094] In one embodiment, the first heated length may range from approximately 0.5 cm to approximately 5 cm, the second heated length may range from approximately 2.5 cm to 20 cm, and the third heated length may range from approximately 5 cm to 40 cm.

[0035]

[0095] In some embodiments, the catheter further comprises a push button on the handle.

[0096] In another embodiment, the TRS style connector is a tip-sleeve, tip-ring-sleeve, tip-ring-ring-sleeve, tip-ring-ring-ring-sleeve, or other suitably configured push-fit or blind-fit configuration.

[0036]

[0097] In some embodiments, the heating element comprises a generally helically shaped resistive heater coil.

[0098] A method for treating a patient's perforator veins is provided, the method including the steps of accessing the patient's perforator veins at an access location located above the patient's fascial layer with a cannula assembly; introducing a flexible heating catheter through the cannula assembly into the perforator vein at the access location above the fascial layer; advancing the heating catheter within the perforator vein, past the fascial layer, to a first treatment location within the perforator vein and below the fascial layer; activating a heating element of the heating catheter to provide thermal therapy at the first treatment location; retracting the heating catheter within the perforator vein to a second treatment location within the perforator vein; and activating a heating element of the heating catheter to provide thermal therapy at the second treatment location.

[0037]

[0099] In some embodiments, the second treatment location is located within the perforator vein and below the fascial layer.

[0100] In one embodiment, the method further includes retracting the heating catheter within the perforator vein to a third treatment location within the perforator vein and activating a heating element of the heating catheter to provide thermal therapy at the third treatment location.

[0038]

[0101] In some embodiments, the third treatment location is located within the perforator vein and above the fascial layer.

[0102] In other embodiments, the second treatment location is located within the perforator vein and above the fascial layer.

[0039]

[0103] In one embodiment, the method further comprises imaging the heated catheter with real-time ultrasound imaging.

[0104] In some embodiments, the method includes identifying successful occlusion of the perforator veins under real-time ultrasound imaging.

[0040]

[0105] In another embodiment, the method includes identifying a diminishing bubbling effect in a vein under real-time ultrasound imaging.

[0106] In some embodiments, the heating catheter further comprises a circuit board having firmware that is stamped with the catheter type during production.

[0041]

[0107] In other embodiments, the heating catheter is rendered inoperable by the energy delivery controller if the energy delivery controller does not recognize or accept the engraved catheter type. [Brief explanation of the drawings]

[0042] [Figure 1]

[0010] FIG. 1 illustrates an example of an energy delivery system for providing intravenous thermal ablation. [Figure 2]

[0011] FIG. 1 illustrates an example of a heating element of a heating catheter for providing intravenous thermal ablation. [Figure 3] 1 is an exemplary cross-sectional view depicting a heating catheter. [Figure 4A] FIG. 4A is a diagram depicting an example heating element of a heating catheter. [Figure 4B] FIG. 4B is a diagram depicting an example heating element of a heating catheter. [Figure 5A] FIG. 5A is an example diagram depicting an example heating element of a heating catheter. [Figure 5B] FIG. 5B is an example diagram depicting an example heating element of a heating catheter. [Figure 6] FIG. 1 is an exemplary block diagram depicting a heating catheter. [Figure 7] FIG. 1 depicts an exemplary central processing unit for a heating catheter. [Figure 8]

[0017] FIG. 1 is a diagram depicting an example heater resistance measurement engine and an example power router engine of a heating catheter. [Figure 9]

[0018] FIG. 1 depicts an example thermocouple amplifier and an example temperature reference engine of a heating catheter. [Figure 10]

[0019] FIG. 1 depicts an example communication engine of a heating catheter. [Figure 11A] FIG. 11A is a diagram depicting exemplary communication connections for a heating catheter. [Figure 11B] FIG. 11B is a diagram depicting exemplary communication connections for a heating catheter. [Figure 11C] FIG. 11C is a diagram depicting exemplary communication connections for a heating catheter. [Figure 12]

[0021] FIG. 1 is a diagram depicting exemplary communication lines connecting a heating catheter to an energy delivery control device. [Figure 13]

[0022] A diagram depicting exemplary tip, ring, and sleeve cable connections and lines that can be used to connect a heating catheter to an energy delivery control device. [Figure 14A] FIG. 14A is a diagram depicting exemplary communication lines between a heating catheter and an energy delivery controller. [Figure 14B] FIG. 14B is a diagram depicting exemplary communication lines between the heating catheter and the energy delivery controller. [Figure 14C] FIG. 14C is a diagram depicting exemplary communication lines between the heating catheter and the energy delivery controller. [Figure 15]

[0024] FIG. 1 is an exemplary diagram depicting an example energy delivery control device. [Figure 16] FIG. 1 is an exemplary block diagram depicting an energy delivery control device. [Figure 17]

[0026] FIG. 1 depicts an exemplary central processing unit for an energy delivery control device. [Figure 18] FIG. 10 depicts exemplary pulse period lengths provided from the CPU to the power driver. [Figure 19]

[0028] FIG. 1 depicts an example low-pass filter, discriminator, and Schmitt buffer of a shared power delivery and communication legitimizer. [Figure 20]

[0029] FIG. 10 depicts an example of a shared power delivery and communication justification device. [Figure 21]

[0030] FIG. 10 depicts exemplary steps for filtering data signals transmitted over a shared power delivery and communication ground. [Figure 22]

[0031] FIG. 1 depicts an exemplary power driver and short circuit protection engine for an energy delivery controller. [Figure 23]

[0032] A diagram depicting an example power switching engine for an energy delivery control device. [Figure 24]

[0033] A diagram depicting an example multi-voltage power supply that may be used by the energy delivery control device. [Figure 25]

[0034] FIG. 1 depicts an example Secure Digital (SD) card that may be used with the energy delivery controller. [Figure 26]

[0035] A diagram depicting an example sound processor and audio output that may be used with the energy delivery control device. [Figure 27]

[0036] A diagram depicting an example touch screen display that may be used with the energy delivery control device. [Figure 28]

[0037] A diagram depicting an example real-time clock that may be used with the energy delivery control device. [Figure 29]

[0038] FIG. 1 depicts an exemplary flash memory that may be used with the energy delivery control device. [Figure 30]

[0039] FIG. 1 depicts an example electromagnetic interference (EMI) filter that may be used with the energy delivery controller. [Figure 31]

[0040] FIG. 1 is an exemplary diagram depicting a heating catheter placed within a venous lumen. [Figure 32] FIG. 10 depicts an exemplary power-time curve for powering a heating catheter. [Figure 33A] FIG. 33A is a diagram depicting an exemplary technique that may be utilized to promote self-centering heating within the venous lumen. [Figure 33B] FIG. 33B is a diagram depicting an exemplary technique that may be utilized to promote self-centering heating within the venous lumen. [Figure 33C] FIG. 33C is a diagram depicting an exemplary technique that may be utilized to promote self-centering heating within the venous lumen. [Figure 34A]

[0043] FIG. 34A depicts an exemplary heating catheter designed to facilitate dual-zone heating within the venous lumen. [Figure 34B] FIG. 34B depicts an exemplary heating catheter designed to facilitate dual-zone heating within the venous lumen. [Figure 35A]

[0044] FIG. 35A is a diagram depicting an exemplary heating catheter air passageway designed to facilitate visualization of the heating catheter with ultrasound. [Figure 35B] FIG. 35B is a diagram depicting an exemplary heating catheter air passageway designed to facilitate visualization of the heating catheter with ultrasound. [Figure 36A]

[0045] FIG. 1 is a perspective view of an embodiment of a single heated segment treatment catheter with a push button handle and a TRS connector. [Figure 36B]

[0046] FIG. 36B is an enlarged cross-sectional view of the catheter of FIG. 36A showing the rounded distal end, the location of the coil segments, and the location of the thermocouples within the coil segments. [Figure 37]

[0047] FIG. 1 is a schematic diagram of a circuit for galvanically isolating a catheter thermocouple from a catheter heating element. [Figure 38]

[0048] FIG. 1 illustrates one embodiment of a multi-segment heating catheter. [Figure 39A]

[0049] 36B illustrates several steps in the use of the flexible catheter of FIG. 36A introduced through a percutaneous sheath within a perforator vein. [Figure 39B] 36B illustrates several steps in the use of the flexible catheter of FIG. 36A for advancement within a perforator vein. [Figure 39C] 36B illustrates several steps in the use of the flexible catheter of FIG. 36A to perform thermal treatment on a segment of a perforator vein below the fascial layer. [Figure 40A]

[0050] 36B is a graph of the temperature measured over a 20 second treatment period delivered by the catheter in FIG. 36A as measured by a thermocouple positioned as shown in FIG. 36B. [Figure 40B]

[0051] 39B is a graph of the external temperature near the treatment coil of the catheter of FIG. 36A measured at points adjacent the distal, central, and proximal portions of the heating coil during the implementation of the 20 second treatment period of FIG. 39A. [Figure 41]

[0052] 10A-10C illustrate a method for selecting a single segment thermal therapy TRS catheter or a multiple selectable thermal segment therapy TRS catheter to deliver therapy to a treatment site within a patient's venous vasculature. [Figure 42A]

[0053] FIG. 42A is a diagram illustrating a "TRS type connector" that includes a TS design. [Figure 42B] FIG. 42B is a diagram illustrating a "TRS-type connector" that includes a TRS design. [Figure 42C] FIG. 42C is a diagram illustrating a "TRS-type connector" that includes a TRRS design. [Figure 42D] FIG. 42D is a diagram illustrating a "TRS-type connector" that includes a TRRRS design. [Figure 43]

[0054] 1 is a flow chart illustrating one method for treating a patient's perforator veins with thermal therapy. [Figure 44]

[0055] 10 is another flow chart illustrating a method for treating a patient's perforator veins with thermal therapy. DETAILED DESCRIPTION OF THE INVENTION

[0043]

[0108] Generally, various aspects and embodiments of the present invention relate to medical methods and devices for a heat treatment catheter that is suitable for use in the thermal treatment of vascular structures when coupled to a compatible generating device via a TRS connector. More particularly, some embodiments relate to the design and use of a heat treatment catheter having one heat treatment segment or two or more heat treatment segments for thermally coagulating and / or shrinking vascular structures, including blood vessels of the venous vasculature. More specifically, single heat treatment segment catheters can be configured for the treatment of perforator veins connecting superficial veins to deep veins in the legs, superficial venous trunks of the legs (e.g., the great saphenous vein, the small saphenous vein, and the like), as well as superficial tributary veins of the legs, internal testicular veins (varicocele), ovarian veins, gonadal veins, rectal vessels, fallopian tubes, arteriovenous malformations, arteriovenous fistula branches, esophageal varices, and the like. The devices and methods described herein for thermal treatment catheters are applicable whether single or multiple thermal treatment segment catheters are utilized, including use in treating perforator veins with a single thermal treatment segment catheter configured for use with a generator via a blind connection such as a tip-ring-sleeve embodiment or other suitable connector compatible with the generator described herein.

[0044]

[0109] 1 depicts an example energy delivery system 100 for performing thermal ablation. In this example, energy delivery system 100 includes a heating catheter 102, which is a long, thin, flexible or rigid device that can be inserted into a narrow anatomical lumen, such as a vein, and an energy delivery controller 104. Heating catheter 102 is connected to energy delivery controller 104 to provide energy that causes heating at the distal end of heating catheter 102, which can be placed within the lumen of the vein to be treated.

[0045]

[0110] FIG. 2 depicts a heating catheter 102 having a heating element 106 that is heated by an electric current. The electric current generated within the heating element 106 transfers thermal energy to the vein wall by conduction (conductive heating). In certain implementations, the active heating length of the heating element 106 may be user-selectable. For example, the active heating length may be selectable from 1 cm to 10 cm. In this example, a user (e.g., a doctor, surgeon, etc.) may select a heating length as small as d (e.g., 1 cm) up to a maximum length D (e.g., 10 cm) by, for example, selecting a switch on the heating catheter 102 or the energy delivery control device 104. Here, markings 108, 110 may be provided at different lengths along the heating catheter 102 to guide the user with a visual cue, such as a series of dots 110 spaced approximately equal to the length of the shortest heating length d, and another visual cue, such as a series of lines 108 spaced approximately equal to the length of the longer heating length D. This may be done to indicate where the shorter lengths of heating are or to facilitate local location and heating of the shorter lengths of heating within the vessel.

[0046]

[0111] In certain implementations, the markings 108, 110 may be geometric lines or shapes, alphabetic letters, color-coded features, or combinations thereof. In further variations, the markings 108, 110 may be spaced approximately equal to the length of the heating elements 106 (e.g., 10 cm apart when the heating elements are 10 cm long) or slightly longer than the heating elements 106 to prevent accidental overlap of treatments (e.g., 10.1 cm apart when the heating elements are 10 cm long). Preventing overlap of heating segments has two primary advantages. First, avoiding overlap aids in the speed of the procedure as treatments ablate the longest possible length of the vessel with each treatment, and second, overlapping treatments results in additional heating in the overlapping areas, which can result in unnecessary tissue damage. The markings 108, 110 may include alignment markings to facilitate the location of the heating elements and / or tube attachment.

[0047]

[0112] In certain implementations, markings or distinguishable features can indicate a minimum distance of treatment away from the active length of the heating element 106, providing a cue to the user to avoid heating tissue too close to the patient's skin. In one example, the markings or tubing or adhesive edge can be 2.5 or 3.0 cm proximal to the proximal end of the heating element 106.

[0048]

[0113] FIG. 3 depicts a cross-sectional view of the heating element 106. In this example, the treatment catheter 102 may consist of a tube 112 around which a coil 114 is wrapped or disposed. The coil 114 has an associated resistance that allows current to pass through the coil 114, causing it to heat, thereby generating thermal energy that is ultimately applied to the vein wall by conduction (conductive heating). The tube 112 provides a passageway through which wires 118, 120 may extend to provide electrical connection between the coil 112 and the catheter handle, ultimately communicating with the energy delivery controller 104. A smaller tube 113 is inside the tube 112 to facilitate the infusion of fluids or the passage of guide wires. Other items, such as temperature sensors and the like, may also use the passageway provided by the tube 112. In certain implementations, a wire loading passage may be cut into the tube 112 through which the wires 118, 120 connecting the coil 114 may be threaded to conceal and protect these wires and reduce the profile of the heating catheter 102. Additionally, a non-stick outer layer 116 may be provided over the coil 114 of the heating element 106 to, for example, prevent direct contact with venous tissue and promote smooth and easy movement of the heating catheter within the venous lumen.

[0049]

[0114] In certain implementations, the non-stick outer layer 116 can be shrink tubing made from polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), or another applicable outer jacket, preferably, but not necessarily, a low surface energy material. Additionally, a higher friction outer jacket, such as a fluorinated or parylene-coated polyethylene terephthalate (PET) layer, can be treated to have reduced friction. Furthermore, additional sections of heat shrink tubing (e.g., PET, 0.0005 to 0.001 inches thick) can be placed over one or both ends of the non-stick outer layer to strengthen assembly of the heated catheter 102. Alternatively, the coil 114 can be coated to prevent sticking to tissue, such as blood vessel walls.

[0050]

[0115] In certain implementations, the outer diameter of the heating element 106 and heating catheter 102 may be 7F (2.33 mm) or less (e.g., 6F (2.0 mm), 5F (1.67 mm), 4F (1.33 mm), etc.). The length of the heating element 106 may be equivalent to the length of the shortest blood vessel typically treated. For example, the heating element 106 may be approximately 10 cm long for treating long blood vessels, and in another example, the heating element 106 may be approximately 1 cm long for treating short blood vessels. In various other examples, the heating element length may be 15 cm, 7 cm, 5 cm, or 3 cm. The heating element 106 may be covered with a non-stick outer jacket having a thickness of, for example, approximately 0.0005 to 0.001 inches, or approximately 0.001 to 0.003 inches. Short catheter heating lengths are often combined with a technique in which the heating catheter is slowly retracted along the lumen of the blood vessel (continuous pullback ablation), causing the venous lumen to close in a manner similar to a clothing zipper that closes the opening when a slider is pulled. Longer catheter heating lengths are often combined with a technique in which the venous lumen is heated while the catheter is stationary, causing a section of the venous wall to simultaneously contract to closure (partial ablation).

[0051]

[0116] In certain implementations of the exemplary energy delivery system, the heating element 106 may be made from a coiled configuration (single or double lead) of wire (i.e., wire). Accordingly, FIGS. 3-4 depict the coiled configuration of wire making up the heating element 106. In the example of FIG. 3, the wire cross-section 112 has a rectangular profile, but the profile may also be circular or oval to increase the cross-sectional area while decreasing the outer diameter of the heating element 106 for the purpose of efficient generation of heat within the coil by rapid transfer of heat to the surrounding body tissue intended to be treated. Exemplary materials for the heating element 106 may be, among others, stainless steel (a commonly used heating element material for heating to low temperatures, such as below approximately 300°C); nichrome wire; ferroalloy; nickel titanium; Elgiloy; MANGANIN® or an alloy of approximately 86% copper, 12% manganese, and 2% nickel; MONEL® or an alloy primarily composed of nickel (up to 67%) and copper with small amounts of iron, manganese, carbon, and silicon; or a nickel alloy.

[0052]

[0117] 4A and 4B depict diagrams of the heating element 106 of the heating catheter 102. The helical shape of the coil 114 around the tube 112 may be more apparent in the diagram relative to FIG. 3. In certain implementations, a temperature sensor 124 (e.g., a thermocouple or thermistor) may be located along the length of the heating coil 114, such as 1-3 cm from the distal end of the heating catheter 102. As discussed above, the temperature sensor 124 may be located between the coil turns (with spacing or insulation to prevent shorting across the coil), over the coil assembly (e.g., insulated by a layer covering the metal coil, such as FEP, PTFE, or parylene, to prevent shorting across the coil), under the coil assembly, or within the body of the heating catheter 102 under the heating element area. The wiring 122 connecting to the temperature sensor 124 may be directed into the body or tube 112 of the heating catheter 102 near the point where the temperature sensor 124 is active in the measurement, or the wire may be directed by one of the wiring methods described herein.

[0053]

[0118] In certain implementations, an in-wall tube wiring configuration is used below the heating element 106, where bifilar thermocouple wires are embedded within the wall thickness of the tube, the bifilar wires are exposed at the intended measurement locations by laser drilling or the like, and electrical connections are made before or after loading the heating element 106 onto the tube 112. In one example, the thermistor is placed within a depression created by permanently deflecting one or more heating coil turns inward. In one embodiment, the thermistor is placed within a depression in the tube surface onto which the heating coil is loaded; such a depression may be created by cutting a pattern into the surface of the tube or by thermally modifying the surface.

[0054]

[0119] In certain implementations, the treatment catheter 102 is manufactured for a single use, after which the treatment catheter 102 is disposed of. Therefore, the individual parts or components of the treatment catheter 102 are selected with cost reduction in mind. For example, a low-cost heating element 106 may be constructed using a rectangular profile stainless steel wire approximately 0.002 to 0.005 inches thick and approximately 0.020 to 0.025 inches wide, wound into coils with a pitch length of 0.030 to 0.040 inches, creating a gap between the coils of approximately 0.005 to 0.020 inches. If the coils are touching, or may occasionally touch, the coil wire may be coated (e.g., with a 0.0005 inch to 0.005 inch layer of polyimide, PTFE, FEP, PET, perfluoroalkoxyalkane (PFA), or other coating) to electrically insulate each coil. Alternatively, an amount of non-conductive material may be placed in the space between successive coils, such as a filament wound between the coils similar to a double helix configuration, to provide a physical barrier against direct coil-to-coil contact.

[0055]

[0120] In various implementations, additional electrical insulation to or between the coils 114 may not be necessary if the gap between the coils 114 is sufficient to prevent direct coil-to-coil contact when the heating element 106 of the treatment catheter 102 is bent to the tightest radius expected during use. To this end, a more preferred gap between the coils 114 may be approximately 15% to 33% of the width of the coil element, as a larger gap reduces the available heating area of ​​the heating element 106 in a coiled configuration.

[0056]

[0121] In a specific implementation, for a 10 cm heating length, an exemplary heating coil resistance is approximately 8 Ω, with approximately 2 Ω resistance in the catheter wires and cables, when heated to a maximum power level of 57.1 W by a 24 V power supply at 2.38 A. For a 7 cm heating length, an exemplary heating coil + wire resistance is approximately 14.4 Ω when heated to a maximum power level of 40 W by a 24 V power supply at 1.67 A. For a 1.0 cm heating length, an exemplary heating coil + wire resistance is approximately 101 Ω when heated to a maximum power level of 5.7 W by a 24 V power supply at 0.238 A. AC power supplies such as 12 V, 9 V, and 3 V have the relationships I=P / V [A=W / V] and R=P / I. 2 [Ω=W / A 2 ] have different resistance range needs.

[0057]

[0122] In certain implementations, the two ends of the heating element (in a single-lead coil configuration) may be soldered to copper or similar conductors of sufficiently low resistance that extend through or along the length of the energy delivery catheter shaft to a handle or cable connector that ultimately connects to the energy delivery system. One or more temperature measurement features (e.g., thermocouples, thermistors, resistance temperature detectors) may be located along the length of the heating element or configured within the heating element. It may be beneficial for the thermocouple location to be within the region visible by ultrasound while imaging the tip of the catheter. Because linear ultrasound probes are often approximately 2.0-4.0 cm wide, an exemplary location for temperature measurement is 1.0-3.0 cm proximal to the distal end of the heating coil. It is important to place at least one such temperature measurement feature (when one or more are included in the device) within the region of the heating element most likely to be compressed tightly against the vein wall; when the heating element is partially visualized by the ultrasound probe during treatment, that region of compression is typically within the most distal 3.0-4.0 cm of the heating element.

[0058]

[0123] FIG. 5A depicts an example 500 of a heating element 502. In this example, the heating element 502 is shown as a long resistor having a length D and a resistance R, where current flowing through resistor R creates heat. In certain implementations, the active heating length of the heating element may be selectable and adjustable by the user. As a result, the thermal ablation heating catheter 102 can be used to quickly treat long vein segments, but can also treat much shorter lengths. Accordingly, FIG. 5B depicts a heating catheter 550 with a first heating element portion 552 having a length d1 and a resistance R1 and a second heating element portion 554 having a length d2 and a resistance R2. In this example, d2 is longer than d1, and d1 and d2 collectively equal the length D. Thus, depending on the desired treatment, the user can select to have the desired heating length using switch 556. In this example, when switch 556 is switched to A, only the first heating element 552 corresponding to length d1 will be turned on, and when switch 556 is switched to B, in this example, the first heating element 552 and the second heating element 554 will be turned on.

[0059]

[0124] In certain implementations, length D is 10 cm and d1 is 1.0 or 2.5 cm long. Another example configuration is a 7 cm heating element that can heat along its entire length or only along the most distal 3 cm. A further example configuration is a 6 cm heating element that can heat along its entire length or only along the most distal 2 cm. Three selectable lengths, such as 10 cm, 3 cm, or 1 cm, are also advantageous, although it should be understood that any number of selectable lengths are possible.

[0060]

[0125] In certain implementations, for the same energy delivery system to effectively power and control both longer and shorter length heating elements (either switchable on the same energy delivery catheter or using two or more different types of energy delivery catheters), it is desirable to be able to adjust the power supply voltage to a lower value for shorter length devices. As noted above, a 10 cm heating length heated to 57.1 W by a 24 V power supply at 2.38 A may have a resistance of 8 Ω, while a 1.0 cm heating element operated at the same wattage per unit length (5.7 W) using the same 24 V power supply may have a resistance of 80 Ω. One-tenth the length of a 10 cm physical heating element (designed to have a resistance of 8 Ω over a 10 cm length) has an inherent resistance of 0.8 Ω, which is only one-hundredth of the target resistance for operation at 24 V. Indeed, this shorter 1.0 cm heating element length (with a 0.8 Ω resistance) can be driven by 2.38 A at 2.4 V. This reduced voltage is achieved using a transformer (e.g., a ferrite transformer) or resistor, and may preferably be built into the energy delivery control device 104, or alternatively, it may be built into the heating catheter 102 (e.g., in the handle or cable assembly). More practical voltages are 9 V and 3 V, with appropriately balanced heating element resistance to achieve maximum heating of approximately 5.7 W / cm, which is reduced to lower levels of heating as needed to maintain the target temperature. This level of heating compares well with studied protocols for thermal ablation of veins at 120°C with reasonably fast heating times, although it should be noted that alternative perturbations of higher or lower maximum heating may also be employed; examples are greater than 6 W / cm for even faster heating rates or to higher temperatures or over larger diameter heating elements, or less than 5 W / cm for slower heating or to lower temperatures.

[0061]

[0126] In a specific implementation, the heating element 106 has at least three connections for switchable heating lengths (first heating element 552 or first heating element 552 + second heating element 554), and each of the two heating segments of the heating element includes a temperature sensor. One example configuration is a heating element 106 with a distal heating length of 2.5 cm (temperature sensor mid-length at 1.25 cm) and a proximal heating length of 7.5 cm (temperature sensor mid-length at 3.75 cm). A more specific implementation configures energy control to the heating element 106 so that either or both heating segments can be actively heated, such that each segment can be independently controlled to reach and maintain a therapeutic temperature. A preferred configuration is for the electrical connections within the length of the heating element (not the connections at the two ends) to a shared ground. A similar specific implementation could be a 20 cm heating element configured as a 10 cm heating segment. More than two segments could be similarly configured.

[0062]

[0127] In certain implementations, electrical bonding of conductive wires to the heating element by solder is facilitated by plating at least a portion of the heating element with another material that is easier to solder (e.g., does not require corrosive acid flux). Exemplary plating materials are gold, tin, and nickel. Plating can be done from component wire before the wire is formed into the heating element shape (such as plating wire spool-to-spool), or the finished heating element shape can be plated. The entire heating element can be plated, or selected areas at the solder contact locations can be plated.

[0063]

[0128] In certain implementations, the distal tip of the heating catheter 102 may have a rounded end (fully round), or it may be shaped like a dilator with an overall tapered shape so that the heating catheter 102 can be introduced directly into a vein over a long access guidewire without the need for an introducer sheath. A lumen (e.g., for a guidewire or for fluid passage therethrough) may be present, extending from the tip through the length of the heating catheter shaft to a handle or connector at the proximal end of the heating catheter 102. The lumen may be sized to slidably receive a guidewire of approximately 0.014 inches, 0.018 inches, 0.025 inches, or 0.035 inches in diameter. Alternatively, the lumen may terminate midway along the heating catheter shaft, such as exiting a side port approximately 20 cm proximal to the distal tip. The inner lumen can feature elongated ribs that act as standoffs to reduce the surface area of ​​the lumen contacted by the guidewire, reducing friction. In certain implementations, there are no guidewires or fluid lumens within the body of the heating catheter 102.

[0064]

[0129] In certain implementations, a handle or connector hub for the thermal ablation heating catheter 102 connects to the catheter shaft, which contains the electrical connections for the heating element conductive wire leads and the temperature sensor 124 leads, as well as providing a fluid connection with the guidewire lumen (if present). The handle may also include a button or activation feature that communicates with the energy delivery controller 104 to indicate the user's readiness to begin (or prematurely stop) heating treatment. The handle button may be located on the top or side of the handle, or the handle design may be configured to allow the handle to be pressed or squeezed on either side for activation. The start / stop activation feature may prevent unintentional activation of treatment initiation, which may be achieved by requiring a greater force than would normally be applied by accidental contact and / or by including geometric features that act to prevent unintentional contact with the activation feature. In one embodiment, the handle has a highly textured surface to provide maximum grip; such a surface may be incorporated as a feature in the injection mold for the part, with a generally tapered pocket between 0.001 and 0.01 inches deep, which may be positioned at an angle as the part exits the mold.

[0065]

[0130] Figure 6 depicts an example block diagram of the heating catheter 102. In a particular implementation, the heating catheter 102 includes a central processing unit (CPU) 600 in communication with a temperature reference engine 602, a debouncing circuit 604 for a push button 606, a thermocouple amplifier 608 for a thermocouple 610, a power router 616, a heater resistance measurement engine 618, and a communications engine 620. Figure 7 depicts an example circuit diagram of the CPU 600 and the push button 606 according to one particular implementation. The power plus side is provided from the energy delivery controller 104 to the heating catheter 102, is selected by the power router 616 to reach heater B 612 or a combination of B 612 and A 614, and exits the power minus side. 5B, the connection of heater A 614 and heater B 612 to power router 616 allows a user to selectively switch between using only heater B 612 or both. In these figures, heater A 614 and heater B 612 are similar to 552 and 554 (612≈552, 614≈554, and 616≈556).

[0066]

[0131] In this example, the heater resistance measurement engine 618 can monitor and measure the resistance of a selected heater. FIG. 8 depicts an example circuit diagram of the heater resistance measurement engine 618 and the power router 616, according to one particular implementation. The thermocouple amplifier may convert the thermocouple resistance received from the heater resistance measurement engine 618 to temperature, for example, with cold junction compensation, and / or may accept input from a thermistor. More than one temperature input may be included. FIG. 9 depicts an example circuit diagram of the thermocouple amplifier 608 and the temperature reference engine 602, according to one particular implementation. Additionally, the communication engine 620 is connected to the short-circuit protection engine 622, and data from the communication engine 620 can be sent back to the energy delivery controller 104 via the communication and power minus side through the communication engine 620. Accordingly, FIG. 10 depicts an example circuit diagram of the communication engine 620, according to one particular implementation. The heating catheter 102 may also have a memory module for storing information such as device identification and operating parameters for the energy delivery controller 104, device-specific calibration information, and test and / or product usage history. This memory module may also be integrated into the microprocessor, control engine, or CPU 600.

[0067]

[0132] In certain implementations, at least a portion of the heated catheter 102 may be provided for user sterilization in a sterile barrier package (e.g., a Tyvek-Mylar pouch, a permeable or impermeable pouch, or a thermoformed tray with a permeable membrane lid). In further variations, methods such as ethylene oxide sterilization, gamma sterilization, E-beam sterilization, or hydrogen peroxide gas sterilization may be included to sterilize the heated catheter 102.

[0068]

[0133] In certain implementations, the sterile barrier package consists of a tube (e.g., high-density polyethylene (HDPE)) held in a coiled configuration, with at least one end allowing the heated catheter 102 to be introduced inside the coil for protection. A component (e.g., a die-cut flat card, a thermoformed tray or clamshell, or a molded shape) can be configured to hold both the coil and the catheter handle and / or cable. The catheter handle can be configured to hold a portion of the coil.

[0069]

[0134] In certain implementations, the electrical connection between the heating catheter 102 and the energy delivery controller 104 can be made by plugging a long catheter cable (constructed as part of a disposable energy delivery catheter) directly into the energy delivery controller 104. Additionally, a user-sterilizable, multi-use cable can connect between the energy delivery catheter handle and the energy delivery system. FIGS. 11A, 11B, and 11C illustrate the controller connector 1100, thermocouple connector 1102, and first and second heater connectors 1104. In certain implementations, the electrical connection can be made partway between the heating catheter 102 and the energy delivery controller 104, for example, 18 inches from the edge of the sterilization operating table (with an energy delivery catheter cable length of 24 to 36 inches).

[0070]

[0135] In certain implementations, a push-fit type connector (such as an IA" mono or tip, ring, and sleeve (TRS) stereo plug, a card-edge connector, or a LEMO® style connector) may be used to connect the heating catheter and the energy delivery system. The electrical connection may be facilitated by being magnetically coupled. The electrical wiring of the energy delivery catheter may be bundled wires, twisted pair wires, or a generally parallel monofilar or bifilar cable.

[0071]

[0136] FIG. 12 depicts an example cable configuration 1200 for power delivery and communication that may include a wire bundle having two 20 AWG (e.g., 26 / 0.16BC) wires for power delivery 1202 (red) and a common ground 1204 (e.g., PVC coated with red and black insulation, respectively), and a 30 AWG (e.g., 7 / 0.1BC) communication wire 1206 (e.g., PVC coated with blue insulation) for communication. The cable configuration 1200 may be provided highly shielded with a shield 1208, such as a helically wound copper wire bundle (e.g., 72 / 0.102BC), a braided wire shield, a conductive tape-wrapped shield, or the like. The wire size and gauge may be reduced or increased in other similar implementations. The entire cable is covered with a jacket 1210 of PVC, thermoplastic elastomer (TPE), or a similar non-conductive material.

[0072]

[0137] 13 depicts an example TRS plug 1300 that may be used, in a particular implementation, as an electrical connection between the cable configuration 1200 (attached to the heating catheter 102) and the energy delivery controller 104. In this example, the TRS plug 1300 is a 0.635 cm (¼ inch) TRS stereo barrel plug having three conductors: a tip 1302, a ring 1304, and a sleeve 1306. The four conductors of the cable (including the shield 1208) can be made to work with a three-conductor TRS plug such as the TRS plug 1300 by connecting the (red) power delivery 1202 wire to the tip 1302, the (blue) communication wire 1206 to the ring 1304, and both the (black) ground wire 1204 and the shield 1208 to the sleeve 1306.

[0073]

[0138] In certain implementations, the shield 1208 terminates near the handle of the heating catheter 102 and is not commonly connected to the ground wire 1204 at the handle. This is shown as three possible configurations in FIGS. 14A-14C. Thus, FIG. 14A depicts a first example wire configuration 1402 in which a single wire provides both power delivery and communication to the heating catheter 102, with a single ground wire acting as a ground and providing a return path for communications without any shielding. FIG. 14B depicts a second example wire configuration 1404 in which a single wire provides both power delivery and communication to the heating catheter 102, with a single ground wire acting as a ground and providing a return path for communications with shielding (or, in other words, a shield). FIG. 14C depicts a third example wire configuration 1406 in which separate wires provide power delivery and communication to the heating catheter 102, with both wires sharing the same ground wire return path with shielding.

[0074]

[0139] Thus, in certain implementations, only two wires extend between the heating catheter 102 and the energy delivery controller 104. The two wires are used to deliver energy and also to carry data signals (e.g., in the high frequency range), such as serial communications, that are filtered out, e.g., using a low-pass filter, before the energy is conducted to the heating element. The heating catheter 102 may include a momentary switch, such as to provide a start / stop signal for heating. One or more light-emitting diode (LED) lights may be defined on the energy delivery catheter, such as approximately adjacent one or both ends of the heating element 106, or located within the catheter handle, configured to illuminate through the heating element 106. In one example, the LED lights flash in a pattern that makes it easy for a user to distinguish the LED lights from background light.

[0075]

[0140] There may also be one or more piezoelectric ultrasound crystals on the heating catheter 102, such as generally adjacent one or both ends of the heating element 106, configured to deliver a distinct signal within the ultrasound field for visualization in B-mode or color Doppler. There may be a usage control engine that determines whether the energy delivery control device 104 has been used in a recognized procedure and prevents further use after specified conditions, such as the number of treatments and / or the time elapsed since the first clinical use.

[0076]

[0141] In certain implementations, an instruction set (e.g., software) may be present to recognize the heating catheter 102 and apply a corresponding instruction set to manage heating control and information display. The instruction set may observe whether a button is pressed on the energy delivery catheter and then begin or end energy delivery. Energy may be automatically terminated after a predetermined treatment time, after delivery of a desired total or minimum amount of power, or after a combination of the two requirements.

[0077]

[0142] In certain implementations, the energy delivery controller 104 includes a power source and a measurement device. One measurement device may be a Wheatstone bridge, suitable for measuring temperature via thermocouples. Another measurement device may be a thermistor. Another measurement device may be an ohmmeter or similar means for measuring the resistance or impedance of the heating element circuit of the heating catheter 102. Another measurement device may be an ammeter or similar means for measuring or determining the current delivered to the heating element circuit of the heating catheter 102. Another measurement device may be configured to interface with a serial communication element (e.g., a 1-WIRE® chip or a radio frequency identification (RFID) device) of the energy delivery catheter.

[0078]

[0143] In certain implementations, the energy delivery controller 104 communicates with the energy delivery catheter using minimal conductive wires between them, for example, a serial communication protocol over a pair of wires, which may be used not only to deliver energy to the heating catheter 102 (perhaps stored or regulated in a capacitor built into the heating catheter 102 handle or cable, or by signals from the heating catheter 102 that alert the energy delivery controller 104 when to send power and what the voltage and current should be), but also to provide catheter identification data and temperature and / or resistance / impedance feedback.

[0079]

[0144] In certain implementations, the energy delivered to achieve heating of the heating element may be delivered in a series of pulses, similar to pulse-width modulation, but the pulses are configured into a serial communication protocol to achieve bidirectional communication. In one example, a third line is configured for communication from the energy delivery catheter to the energy delivery controller 104. In one example, one or more thermistors are used in the heating element of the heating catheter 102 to simplify temperature measurement and enable such data to be transmitted to the energy delivery controller 104. In an alternative example, one or more thermocouples are used in the heating element, and a cold junction thermocouple and Wheatstone bridge or similar compensation are used in the catheter handle to determine temperature measurements and enable such data to be transmitted to the energy delivery controller 104.

[0080]

[0145] In an exemplary use case, upon insertion of the heating catheter 102 into the energy delivery controller 104, a low-current test voltage within a limited frequency range is applied to the heating catheter 102 and is low- or high-pass filtered to prevent therapeutic levels of energy from being delivered to the heating element 106. A communication handshake may be established between the heating catheter 102 and the energy delivery controller 104, and the heating catheter 102 may transmit an identifier to the energy delivery controller 104 that allows the energy delivery controller 104 to recognize the heating catheter 102 and associate the correct set of instructions to manage it. The heating catheter 102 may also transmit a quality check status that ensures the heating catheter 102 is authentic, functioning properly, and ready for therapy.

[0081]

[0146] The heating catheter 102 may transmit the measured temperature of the heating element 106 at intervals such as 10-100 times per second (10-100 Hz). The heating catheter 102 may transmit the status of a start / stop command, such as when a user presses a button on the catheter handle to begin treatment. When the start / stop command is that the button is pressed to begin treatment, the heating catheter 102 may send a command to the energy delivery controller 104 indicating that treatment should begin, and the energy delivery controller 104 begins transmitting power at the appropriate voltage and / or duty cycle for the active heating length of the heating catheter 102, and at a current sufficient to achieve and maintain the target treatment temperature, using relay temperature or thermocouple resistance from the heating catheter 102 to guide the treatment. The energy delivery controller 104 may display the measured temperature, the level of energy being delivered, and the remaining treatment time.

[0082]

[0147] If the heating catheter 102 has a user-selectable active heating element zone (e.g., the entire length of the heating element 106 or the distal 25% or 10% of the heating element 106), the energy delivery controller 104 may communicate to the heating catheter 102 that delivery power should be routed to the appropriate lines to achieve that heating length. The screen of the energy delivery controller 104 may also show an image identifying which portion of the heating catheter 102 will heat or is being heated. The voltage may be stored (e.g., in a capacitor) and / or ramped up or down to provide sufficient voltage (e.g., 3 V) for the logic portion of the heating catheter 102 that is separate from the delivery voltage for the active heating element length (e.g., 24 V for a 10 cm heating length, 6 V or 9 V for 2.5 cm, and 2.4 V, 6 V, or 9 V for 1 cm). Alternatively, the logic portion of the heating catheter 102 may be powered by a battery in the handle (e.g., a CR2032 button cell, AAA, or other battery). In one example, the two wires in the heating catheter 102 cable can be a twisted or substantially parallel pair (e.g., 16-24 AWG, more preferably 18-22 AWG, preferably twisted for flexibility) shielded within the cable. Connectors for two- or three-wire catheter cables can be coaxial designs, such as coaxial power plugs (as commonly used to plug power cables into laptop computers), coaxial plugs (e.g., TRS or TR) such as those used for headphones and / or microphones, or other connectors, such as 2-3 banana plug connectors or card edge connectors. While TRS connectors are more typically described herein, other "TRS-style" connectors accommodating more than two or three wires are possible, depending on electrical requirements. For example, TRRS (4-wire / contact) or TRRRS (5-wire / contact) connectors are additionally contemplated. (See additional examples in Figures 41A-41D.)

[0083]

[0148] In certain implementations, one or more charge pumps are used within the catheter handle to increase the voltage to a transistor (e.g., a MOSFET) that connects the heating element to the power delivery circuitry. The charge pumps are used to overcome the natural decrease in resistance over time that results from battery use.

[0084]

[0149] As discussed above, an exemplary three-conductor connector used to plug the heating catheter 102 into the energy delivery control device 104 is a 6.35 mm stereo TRS audio plug with three conductors. The tip can provide power, the ring can provide a communications link, and the sleeve can be a common return to ground. This system is shielded from the user so that when the tip first contacts the power source, only the ground can be contacted by the user's hand. In a further implementation, a switch is configured to allow power connection to the 6.35 mm connector jack only when the plug is physically pressed into the jack, so that the tip does not short across the tip and ring ends inside the connector jack. This switch can be configured inside the jack so that the tip of the plug presses and engages the switch, or it can be configured outside so that the body of the 6.35 mm plug handle presses and engages the switch. In a further implementation, circuitry connected to the TRS connector plug and / or jack includes one or more diodes positioned to prevent a short between the tip and ring contacts from damaging the catheter or energy delivery device. In a further implementation, the circuitry connected to the TRS connector plug and / or jack includes one or more fuses positioned to prevent a short circuit between the tip and ring contacts from damaging the energy delivery device or causing overt physical damage to the catheter.

[0085]

[0150] In certain implementations, a separate component sterile sleeve, similar to a sterile ultrasound probe cover, can be designed to interact with the handle / cable connection, providing an easy means of deploying the sterile sleeve to cover a multi-purpose cable. One exemplary way to facilitate deployment of the sterile sleeve is to build it into a rigid or semi-rigid frame that covers the desired length of cable and is attached to the end of the sleeve that will be extended forward to provide surface sterilization. This same frame can be used to stretch a sleeve material tensioner (like a drum skin) at the end that will interface with the heated catheter handle to enable a fluid-tight seal. One way to achieve such a seal is for the handle to pierce the sleeve material and then force it open via a tapered interface that seals against the sleeve material.

[0086]

[0151] Alternatively, the sleeve material may have a molded opening that is smaller than the tapered entry point on the catheter handle but that forcibly stretches the sleeve material to provide a seal against the handle. In one embodiment, a frame is provided that can be used with commercially available ultrasound probe covers to provide a means for easy connection and deployment as described above. In all cases where a sterile sleeve is used, the length of the sterile sleeve should be at least sufficient to cover the cable to the edge of the sterile field, e.g., approximately 30-60 cm.

[0087]

[0152] In certain implementations, the multi-purpose cable is configured to include a radio frequency (RF) antenna that can detect an RFID tag embedded in the catheter near the connection point between the catheter and the cable. In a further example, the cable includes a handle with associated electronics, such as a switch, and the RF antenna is located within the handle so that when the connector to the catheter is plugged into the handle, the RF antenna can read and interact with an RFID tag that is part of the catheter. This RFID tag can be used to identify the device, apply associated parameters from the energy control unit, and further store data including an ongoing history of device usage.

[0088]

[0153] In certain implementations, an alternative way to connect the heating catheter 102 to the energy delivery controller 104 is to use inductive coupling to power the heating catheter 102 across a sterile barrier, so that puncturing the barrier is not necessary. This may be done to provide power to the energy delivery system when it is placed within a sterile field (such as in a sterile envelope) or may be done between the energy delivery controller 104 and the heating catheter 102. Communication between the energy delivery controller 104 and the heating catheter 102, such as for catheter identification, temperature feedback, and device start / stop commands, may be done via wireless protocols such as Wi-Fi, BLUETOOTH, or ZIGBEE.

[0089]

[0154] In certain implementations, the energy delivery system may be a tabletop controller designed to be located outside the sterile field, in a location visible to all participants in the procedure who have a need to see the displayed data or who will physically interact with the system (such as by plugging in an energy delivery catheter). It may also be beneficial for the system to be located near a fluid delivery pump for the local anesthetic solution and / or an ultrasound controller or display screen.

[0090]

[0155] 15 depicts an example diagram of an example energy delivery controller 104. In certain implementations, the energy delivery controller 104 may be located directly adjacent to the sterile field (such as placed on a pole stand with a boom-style arm to hold the device generally above the sterile field) or directly within the sterile field (if placed within a sterile envelope such as a see-through bag, or if the system and power supply are configured to withstand sterilization, such as with steam). Information may be provided to a user of the energy delivery controller 104 on a display screen 1500 (e.g., LCD, LED, flat panel, touch screen) by indicators (e.g., light and / or sound) or by interacting with a remote device such as a cell phone, tablet, or computer. Exemplary information provided to the user may include the power level 1506 being delivered (e.g., instantaneous power in W or W / cm and / or cumulative power in Joules or J / cm), the measured temperature 1504 (e.g., °C), a timer 1502 (e.g., countdown or countup, seconds), alert or status messages, identification 1508 of the connected heating catheter 102, history of previous treatments, system and / or catheter settings, software revision of the energy delivery system, and copyright information. Multiple languages ​​and date / time formats may be supported, as well as being user selectable.

[0091]

[0156] In certain implementations, the energy delivery controller 104 may be powered by facility power (e.g., a wall outlet in the range of 110-240 VAC) with a voltage regulator either built into the system or configured into the power cord (e.g., a corded power supply system that accepts 110-240 VAC as an input and provides 24 V DC as an output). Additionally, the energy delivery controller 104 may be battery-powered. Two or more power modules may be incorporated into the energy delivery controller 104 to provide appropriate voltages for the microcontroller (e.g., 6-20 V, or 7-12 V) and energy delivery voltages (e.g., 12-24 V and 1-5 V, or 18-24 V and 1.8-3 V). In certain implementations, the energy delivery controller 104 is powered by facility power (e.g., 110-112 V or 220-240 V), and the microprocessor in the heating catheter 102 is powered by a battery (e.g., 5 V). In a further implementation, the battery inside the heated catheter 102 has a pull tab that cuts off power until pulled away by the user. In a further implementation, the pull tab is attached to the heated catheter 102 packaging such that the pull tab automatically releases when the user removes the catheter 102 from the packaging.

[0092]

[0157] FIG. 16 depicts an example block diagram of the energy delivery controller 104. In this example, a controller CPU 1600 is coupled to a voltage switch 1602, a power driver 1604, and an overcurrent and short-circuit protection 1606. FIG. 17 depicts a diagram of the controller CPU 1600 that may be used in the energy delivery controller 104. FIG. 22 depicts an example circuit diagram for the power driver 1604 and the overcurrent and short-circuit protection engine 1606, and FIG. 23 depicts an example circuit diagram for the power switching engine 1602 that may be used in the energy delivery controller 104. In certain implementations, control of the intensity of energy provided to the energy delivery catheter may be achieved through amplitude modulation or pulse-width modulation (PWM) of the power signal from the CPU 1600 to the power driver 1604. FIG. 18 depicts an example pulse period length provided from the CPU 1600 to the power driver 1604. In this example, the pulse period may be constant or variable. The degree of applied energy may be modulated by a duty cycle. The pulse amplitude can be constant (eg, 24V) or can depend on the heated length of the element (eg, 24V for 10cm, 9V for 2.5cm, or 3V for 1cm).

[0093]

[0158] For serial communication protocols within the power cycling, switching between heating element lines to activate the desired heating length can be accomplished within the heat delivery catheter (e.g., within the handle) based on the delivered power level (pulse amplitude) or based on keyed pulse(s) of energy delivery that encode device identification. Amplitude modulation can be for electromagnetic wavelengths within the high frequency band, for example. PWM can also use varying pulse widths within the high frequency band.

[0094]

[0159] Thus, signals being transmitted from the CPU 1600 to the heating catheter 102 may travel through the power driver 1604 to the EMI filter 1608 before reaching a connection 1610 corresponding to the cable connecting the heating catheter 102. Figure 30 depicts an example diagram of an EMI filter 1608 that may be used with the energy delivery controller 104 to filter out electromagnetic interference from other components and the like. Thus, signals are transmitted out of and received by the energy delivery controller 104 via a shared power delivery and communication validator (SPDCL) 1614.

[0095]

[0160] In this example, the controller CPU 1600 is coupled to the SPDCL 1614, which receives communication data from the heating catheter 102. In this example, because the line configuration 1200 utilizes a shared ground and communication data return, the SPDCL 1614 must filter out noise caused by sharing the return with the power delivery line. Accordingly, FIG. 19 depicts an example block diagram of the SPDCL 1614. In this example, the SPDCL 1614 includes a low-pass filter 1900, a discriminator 1902, and a Schmitt buffer 1904. Additionally, FIG. 20 depicts a circuit diagram of the SPDCL 1614, including the low-pass filter 1900, the discriminator 1902, and the Schmitt buffer 1904. Accordingly, FIG. 21 depicts example steps the SPDCL 1614 may take to filter data signals being transmitted over the shared power delivery and communication ground lines. In this example, Figure 21 shows signal 2102 and noise 2104 created by sharing the same ground for power delivery and communication return. Thus, Figure 21 shows communication line 2106 and filter output 2108, as well as a Schmitt output 2110 from which communication line 2106 generates gate output 2112. In this way, SPDCL 1614 filters out noise that would corrupt the communication signal being transmitted from heating catheter 102 as it travels down the multi-purpose cable described above on its way to energy delivery controller 104.

[0096]

[0161] In certain implementations, circuitry and component placement is provided within the energy delivery controller 104 in close proximity to the catheter plug-in jack connection 1610 to filter out noise within the system and provide clean power and clear, stable communication between the heating catheter 102 and the energy delivery controller 104.

[0097]

[0162] Referring back to FIG. 16 , the energy delivery controller 104 receives power via a power connector 1636 to a multi-voltage power supply 1634, which is connected to a main control board including the display 1632 and controller CPU 1600 described above. FIG. 24 depicts example circuits for the multi-voltage power supply 1634, power connector 1636, and multi-voltage output 2400, and FIG. 27 depicts an example circuit diagram for the touchscreen display 1632. Additionally, the energy delivery controller 104 may include one or more SD cards. In this example, the energy delivery controller 104 includes SD card circuits 1624A and 1624B. Accordingly, FIG. 25 depicts example circuit diagrams for SD card A 1624A and SD card B 1624B. In this example, the CPU 1600 is connected to an audio processor 1626 that can process audio signals and provide them to an audio output 1628 or speaker to provide alerts and the like to the user. Figure 26 depicts an example circuit diagram for a sound processor 1626 and audio output 1628 that may be used with the energy delivery controller 104. Additionally, the CPU 1600 is connected to a reset switch 1630, a real-time clock 1618, and a flash memory 1616. Accordingly, Figure 28 depicts an example circuit diagram for the real-time clock 1618, and Figure 29 depicts an example circuit diagram for the flash memory 1616 that may be used in the energy delivery controller 104.

[0098]

[0163] 31 depicts an example 3100 of a heating catheter 10 placed within a venous lumen 3102. In a particular implementation of the example treatment method, the venous lumen 3102 can be accessed by a user (e.g., a surgeon, doctor, assistant) using the Seldinger technique. For example, a needle can be placed through the skin 3104 into the venous lumen 3102, then a flexible access line can be placed through the needle into the venous lumen 3102, the needle can be retracted while the access line remains within the venous lumen 3102, a sheath with a vasodilator can be placed over the access line into the venous lumen 3102, and finally the access line and dilator can be retracted while the sheath within the venous lumen 3102 extends out through the skin 3104, providing quick access for the heating catheter 102 directly to the venous lumen 3102.

[0099]

[0164] Alternatively, the venous lumen may be accessed by cut-down (cutting the skin and subcutaneous tissue with a sharp blade, visualizing the vein, cutting open the vein wall, and placing a sheath directly into the venous lumen). For treatment of the great saphenous vein (GSV), vascular access is typically achieved near or just below the knee, or near the inner ankle. A heating catheter is placed into the venous lumen (typically through a sheath) and advanced through the vein to the intended starting treatment site. For GSV treatment, this advancement location is typically at or near the saphenofemoral junction (SFJ) near the patient's groin. Ultrasound visualization is typically used to guide the heating catheter 102 to the SFJ and to precisely deliver heating to the deep vein and / or venous branches.

[0100]

[0165] In certain implementations, in some cases involving tortuous (highly curved) veins or awkward branching angles of side branches that prevent easy insertion of the heating catheter into the advancement location, a guide wire may be used to assist in correct positioning of the heating catheter. In this case, the guide wire is first advanced to the intended starting treatment site, and then the heating catheter is advanced over the guide wire to the intended starting treatment site. The use of a guide wire to facilitate the advancement of the heating catheter is also useful when multiple veins are being treated within the same incision, because treatment of one vein may cause other nearby vessels to spasm (constrict into a narrower lumen), thereby making vascular access and / or catheter advancement more difficult.

[0101]

[0166] In certain implementations, a common method of local anesthesia used with intravenous thermal ablation is by infiltration of nearby tissue surrounding the vein along the entire length of the vein segment to be treated. In this method, an anesthetic solution (e.g., a mixture of lidocaine, epinephrine, and sometimes sodium bicarbonate) is injected through a long needle or cannula into the perivenous space surrounding the blood vessel to be treated. In the case of GSV treatment, the anesthetic solution is injected into the "saphenous eye," a narrow region of tissue between the deep and superficial fascia that, in cross section, resembles an eye shape (an oval pinched at both ends) with the vein near the center. Some other vein segments are not contained within the fascial compartment; in such cases, the anesthetic fluid is injected into nearby tissue so that it generally surrounds the vein to be treated. The injection of anesthetic fluid can serve several purposes, including, but not limited to, local anesthesia for patient comfort during heating, hydrostatic compression of the vein to remove and empty blood from the venous lumen and press the venous wall into direct contact with the heating catheter, and a thermal heat sink to protect surrounding tissue and nerves from heating damage.

[0102]

[0167] In certain implementations, after the heating catheter is in place and local anesthesia is applied, additional strategies may be used to completely empty the venous segment of blood, such as tilting the patient's body into the Trendelenburg position (legs up, head down) and directly compressing the vein with external means, such as manual compression by hand, or wrapping the limb with a compression wrap or sleeve.

[0103]

[0168] In certain implementations, for partial ablation, the heating catheter 102 is heated by the energy delivery control device 104. In one treatment example, the heating element 106 is heated to approximately 120°C for 20 seconds per partial ablation treatment. Proximal to the SFJ, two treatments may be applied, with the heating catheter 102 being moved distally a distance approximately equal to the length of the heating element 106. Distal movement of the heating catheter 102 may be guided by a series of printed markings along the heating catheter shaft, as discussed in FIG. 2, and the user may refer to a data location (e.g., a line drawn on the skin or a visualized distance between the sheath and the nearest marking) that aligns with the shaft markings. For very large veins or aneurysmal sections of the vein, the user may choose to perform multiple treatments (e.g., two to five) within each vein segment. Successive treatments of vein segments may be repeated until the entire desired length of the vein has been treated, after which the catheter (and sheath, if used) is removed from the vein.

[0104]

[0169] In a particular implementation of the treatment example, the desired heating cycle is repeated conditionally relative to the size of the vessel, with vein segments smaller than 10 mm in diameter being treated with one energy delivery cycle, vein segments 10 mm or greater but less than 18 mm being treated with two energy delivery cycles, and vein segments 18 mm or greater being treated with three energy delivery cycles. Additional energy delivery cycles may be added for vein segments closest to the source of reflux (e.g., closest to the SFJ).

[0105] [Table 1]

[0106]

[0170] In certain implementations of example treatments, shorter lengths of veins (such as perforator veins that provide a connection between superficial veins such as the GSV and deep veins such as the common femoral vein) may be treated at higher temperatures and / or for longer treatment times. Examples are treatments at 120°C for 40 or 60 seconds, which may be achieved by two or three 20-second treatments, or treatments at 140°C for 20 or 30 seconds.

[0107]

[0171] In certain implementations of therapeutic examples, heating control is managed to achieve an initial temperature over a period of time and then increase to a higher temperature. In one example, the initial temperature is at or near the boiling point of the fluid (e.g., blood) within the lumen, and then, after an initial period that may cause vascular spasm and / or activate soluble gases from within the surrounding fluid, the temperature is increased above the boiling point of the fluid.

[0108]

[0172] In certain implementations of the treatment example, the heating control may be configured to provide a temperature drop near the end of the treatment, giving the heated tissue more time to adjust as it approaches body temperature again.

[0109]

[0173] In certain implementations of the treatment example, vascular access for short venous segments can be achieved using simpler methods than those previously described. For example, a needle (or short sheath) can be inserted directly through the skin into a perforator vein. The needle can be guided into the vein using ultrasound visualization. In guiding the needle into the vein using ultrasound visualization, the needle can be pushed into the patient toward the field of view until the ultrasound image shows the needle tip within the lumen of the vein and a drop of blood flashback from the end of the needle, indicating that the needle lumen is in fluid communication with the vascular lumen. An energy delivery catheter, either flexible or rigid in design, can then be placed through the needle into the venous lumen. Once the energy delivery catheter is positioned within the venous lumen, the needle can be deflected if desired. The energy delivery catheter can be further advanced along the venous lumen, if desired, and guided by angulation of the catheter shaft, by rotation of the curved tip of the energy delivery catheter, and / or by advancing the energy delivery catheter over a guide wire inserted through the catheter lumen.

[0110]

[0174] In a specific implementation of the example of treating a generally T-shaped (or angled T) vascular junction, such as an anastomosis between a perforator vein and an overlying superficial vein, a method of performing T-shaped ablation may include introducing an energy delivery catheter into the superficial vein at a site distal or proximal to the perforator vein and then advancing it past the perforator vein junction to a more proximal or distal site. Energy may be delivered to the proximal superficial vein segment and reach the vascular junction by partial ablation, continuous pullback with heating, or a combination thereof. The catheter may then be advanced into the perforator vein (ideally past the deep fascial layer and close to the deep vein), and energy may be delivered to the perforator vein by partial ablation, continuous pullback with heating, or a combination thereof. Finally, the catheter can be positioned in the distal superficial vein segment and energy can be delivered to the proximal superficial vein segment by local ablation, continuous pullback with heating, or a combination thereof.

[0111]

[0175] In a specific implementation of another example of treating a T-shaped junction, the energy delivery catheter can be configured to provide a T-shaped heating pattern. Using a T-shaped heating pattern, the junction can be heated by placing the catheter at the junction to align a T-shaped heating pattern applicator with the T-shaped vascular junction, and then heating in place to permanently close or reshape the junction. A T-shaped heating pattern can be created using a device configured to heat along the length of the catheter (similar to the heating elements described herein) but also having side holes along the length of the heating element, and a secondary heating element can be advanced through the side holes. Another way to create a T-shaped heating pattern is to provide a heating element with side holes along its length, and heated fluid (near, at, or above its boiling point) is discharged through the side holes so that the heated fluid creates the intersection of the T-shaped heating pattern.

[0112]

[0176] In another example specific implementation of the treatment of a T-junction, the energy delivery catheter can be configured to provide an L-shaped heating pattern. In the L-shaped heating pattern, the catheter can similarly be placed in alignment with the vascular junction, and then heat can be applied. A similar effect can be achieved by placing a flexible heating element across the generally L-shaped vascular junction to induce a generally L-shaped heating pattern.

[0113]

[0177] In certain implementations, after ablation, compression is applied along the treated vein segment, or compression stockings and / or external compression wraps may be used on the entire limb, typically for several days after treatment. The success of thermal ablation procedures is usually very high, with rates of complete vascular occlusion (no blood flow through the treated segment) of 95% or more one year after surgery. A secondary measure is the rate of no reflux, where blood flow is present but in one direction (toward the heart), as in a properly functioning venous system. Both of these blood flow measures (rates of occlusion and no reflux) are surrogates for actual measures of patient clinical symptoms (e.g., pain, tenderness, mobility, Venous Clinical Severity Score, Chronic Venous Insufficiency Questionnaire (CIVIQ), Aberdeen Varicose Vein Questionnaire (AVVQ™), Reflux Disease Questionnaire).

[0114]

[0178] In certain implementations, energy can be delivered to the intended blood vessel by partial ablation, in which the energy delivery catheter is positioned at one location and remains stationary while energy delivery begins for a predetermined period, after which the catheter is repositioned to the next location. In this manner, a length of blood vessel longer than the heating element can be treated in a series of successive steps. At locations near an anatomical source of greater vascular pressure, such as near the SFJ in the case of GSV treatment, a greater amount of delivered energy can be applied. This can be achieved by repeating the treatment at that location before moving the heating element to the next location, by extending the treatment time, or by increasing the treatment temperature. Movement of the energy delivery catheter can follow markings along the catheter shaft, such as moving the catheter shaft a distance approximately equal to the length of the active heating element.

[0115]

[0179] In certain implementations, the length of treatment time (e.g., 20 seconds, 30 seconds, 40 seconds) or the total amount of energy delivered (e.g., 60 J / cm, 80 J / cm, 100 J / cm, 120 J / cm) may be user-selectable, such as by pressing a touchscreen to select the desired time, or by pressing one of two or more treatment buttons on the catheter handle, where each treatment button specifies the desired treatment time or energy delivery.

[0116]

[0180] In certain implementations, the length of active heating of the catheter is user-selectable between a shorter and a longer active length, where vessels shorter than the longer active length can be treated with the shorter active length, and vessels longer than the longer active length can be treated with the longer active length or a combination of one or more treatments with the shorter active length and one or more treatments with the longer active length.

[0117]

[0181] In certain implementations, energy can be delivered to the intended vessel by pullback ablation, where the heating element active length is heated while the energy delivery catheter is pulled along the vessel lumen; in this manner, heat is applied in a manner similar to painting with a brush.

[0118]

[0182] In certain implementations, control of the actual delivery of energy to the heating element can be via temperature feedback (e.g., proportional-integral-derivative (PID) control) to achieve and maintain a desired treatment temperature by delivering a set power level or by delivering a variable power level according to a power-time relationship. The power-time relationship can be configured to approximate the level of power per hour that would normally be delivered to the intended vessel if the system were temperature controlled to achieve and maintain the desired set temperature. One way to determine such a power-time relationship is by measuring (or recording and later analyzing) the delivered power over a series of time intervals for several vascular treatments by several different users associated with several different patients. Another way to determine such a power-time relationship is by measuring such data from a particular physician or group of physicians. Another way to determine such a power-time relationship is by establishing a benchtop heating configuration that matches the thermal properties of human tissue during heating treatment and then measuring such data as above on a benchtop model.

[0119]

[0183] In one example of power delivery for thermal ablation of refluxing veins, a 7 cm long 7F OD heating element is heated to a set temperature of 120° C. for 20 seconds. In certain implementations, exemplary power levels delivered to achieve and maintain that temperature are approximately 35-40 W for the first second of heating, 30-37 W for the second second, and 27-32 W, 23-29 W, 20-27 W, 18-24 W, 17-23 W, 16-22 W, 16-21 W, 15-20 W, 15-20 W, 15-20 W, 14-19 W, 13-18 W, 13-18 W, 13-17 W, 12-17 W, 12-17 W, and 12-17 W for the third through 20th seconds of treatment, respectively. These same values ​​are each divided by 7 to yield example power levels per centimeter of active heated length. In one exemplary use of the above energy delivery power-time relationship, a 10 cm long 7F OD heating element may have an energy delivery of approximately 50-60 W in the first second of heating, 45-55 W in the second second, and 40-50 W, 35-45 W, 30-40 W, 25-35 W, 24-34 W, 23-33 W, 22-32 W, 21-31 W, 20-30 W, 19-29 W, 18-28 W, 17-27 W, 17-26 W, 16-26 W, 16-26 W, 15-26 W, 15-26 W, 15-26 W in the third through fourth seconds of treatment, respectively; smaller diameter heating elements may heat blood vessels to slightly higher temperatures or for longer periods of time due to the reduced surface area for transferring heat to the tissue.

[0120]

[0184] In certain implementations, the method for setting these energy delivery parameters (as in the example above) for any particular size configuration (e.g., a 6F, 5F, or 4F heating element of a particular length) is to perform a series of treatments within the vessel or surrogate tissue, and temperature-controlled (e.g., PID-controlled) heating is performed to achieve and maintain the desired continuous temperature or variable temperature profile. The measured or recorded energy delivery data is then stored and analyzed in its entirety, and suitable confidence intervals are applied to the upper and lower bounds of the data, or simply the mean or median at each time point is calculated, and the curve is then appropriately smoothed.

[0121]

[0185] FIG. 32 depicts an example power-time curve 3200 for powering a heating catheter. In certain implementations, energy is delivered without temperature measurement, and the energy is delivered at a power-time configuration that matches a typical power-time configuration achieved by a temperature-controlled device, which may be of similar heating element dimensions, or at selected increments above or below such a typical power-time configuration. Exemplary power-time relationships are shown above, such as a 100% power-time curve or a 120% power-time curve. Such configurations without temperature measurement can represent significant cost savings in device construction. In further specific implementations, the catheter consists of a heating element with a non-stick coating on the catheter shaft. The catheter shaft connects to a cable assembly with a minimal handle (which may or may not include a button to start / stop treatment). The cable may plug into the energy delivery controller 104 with a 0.635 cm (1 / 4 inch) TRS stereo plug if the cable is grounded, or with a 0.635 cm (1 / 4 inch) TS mono plug if the cable is not grounded. The cable plug housing may include an RFID tag that can be recognized by the energy delivery controller 104 to identify the catheter type, to verify that the catheter is an authentic, certified product, and to limit the use of the catheter to an authorized number of uses (e.g., single use only, or multiple uses such as 3 or 10).

[0122]

[0186] In certain implementations, in a method of energy control, energy delivery is set to a default or user-selectable total energy delivery (e.g., approximately 60, 80, 100, or 120 joules per centimeter of heating element active length), and energy is delivered until the total value is reached. Smaller amounts of energy (e.g., 60-80 J / cm) are activated by a single press of the catheter button, while larger amounts of energy (e.g., 100-120 J / cm) are activated by double presses of the catheter button in rapid succession. Variable amounts of energy can be measured by varying the length of time the blood vessel is heated to and maintains approximately the desired temperature. Variable amounts of energy can also be measured by varying the approximate temperature to which the blood vessel is heated during similar time intervals. During energy delivery, the instantaneous amount of energy may be modulated by an engine (e.g., a processor or process) to set and maintain a desired temperature (e.g., by PID control), the energy may be set to a constant value, or the energy may be delivered according to a preset power versus time relationship by a lookup table or mathematical algorithm managed by the engine. Conditions may also exist where a larger value of time to deliver the desired total energy, or a minimum cumulative time at or near the set temperature, is selected because energy is not efficiently delivered into the intended treatment tissue, such as a vein wall, when cooling of the energy delivery catheter by excessive amounts of surrounding fluid (e.g., blood) may cause the total energy to be delivered more quickly than would be ideal for successful treatment.

[0123]

[0187] In certain implementations, the delivered power is integrated over time to determine a history of delivered energy (e.g., in Joules (J) or J / cm). If a specific intended energy delivery is desired (e.g., 80 J / cm), energy can be delivered according to a lookup table of delivered energy per elapsed time until the integrated delivered power is equal to or slightly greater than the intended energy delivery. Similarly, energy can be delivered as needed to reach and maintain a desired temperature until the integrated delivered power is equal to or slightly greater than the intended energy delivery.

[0124]

[0188] In certain implementations, various features and methods can be used to facilitate tracking of the energy delivery catheter from the access site to the desired treatment start location of the treatment (e.g., the SFJ when treating the GSV). If the vessels are sufficiently straight without angled vascular branches that would misdirect the catheter following the branches, the energy delivery catheter can simply be pushed through the vasculature to the start location. A guide wire can be inserted through the energy delivery catheter to the start location, and the energy delivery catheter can then be advanced over the guide wire. The energy delivery catheter can be advanced within the body of a longer guide catheter that has previously been advanced to the start location.

[0125]

[0189] In certain implementations, the energy delivery catheter can have an overall curved shape that allows it to be advanced like a guidewire, and rotation of the catheter shaft while advancing can be used to select which branch vessel to follow, with a tip curve bend radius of approximately 3 inches to 8 inches being sufficient. For example, an energy delivery catheter with a curved tip may not have a lumen therethrough. Alternatively, the energy delivery catheter can have a steerable tip, with the radius of curvature being user-adjustable, such as by pulling tension on a line established within one side of the catheter shaft causing that side of the catheter shaft to become shorter in length, effectively bending the catheter shaft.

[0126]

[0190] In certain implementations, a magnetic material, a material susceptible to magnetic force, or an electromagnet may be incorporated near the tip of the energy delivery catheter so that a user can apply a magnetic force to attract the tip in a desired direction. Examples of controllable magnetic sources include rare earth magnets, neodymium magnets, and MRI.

[0127]

[0191] In certain implementations, confirmation of the final catheter position at the point of treatment initiation can be by ultrasound visualization, visualization of light energy transmitted through the skin (such as from a light-emitting diode or diodes constructed within the catheter near the tip, near both ends of the heating element, or near both ends of each user-selectable heating length along the heating element), or surgical cutting of the catheter tip and direct visualization or palpation. An exemplary distance from the nearest deep vein is 2 centimeters. The catheter can have a fixed guide wire attached to its tip. This has the advantage of aiding catheter navigation through the vasculature (similar to a standard guide wire), and it can also be used as a visual guide to be precisely extended a desired length beyond the area of ​​catheter heating (such as 2 cm distal to the heating element) and aligned with an anatomical structure, such as aligning the tip of the fixed guide wire with the SFJ.

[0128]

[0192] In certain implementations, a method of alerting a user when vascular heating is not progressing in a typical manner according to the intended treatment (such as heating a superficial vein after an anesthetic fluid has been injected to surround and empty the blood vessel, such that the energy delivery catheter is primarily heating the vein wall as opposed to heating the bulk of the fluid, such as the blood surrounding the catheter) is to provide a time-variable maximum power level to the heating catheter. In such cases, if an abnormal amount of fluid is present around the heating element (providing a cooling effect in that area and countering the intended heating of the vessel wall), the set temperature cannot be achieved or maintained, and the user will notice that the treatment temperature displayed on the energy delivery control device 104 has fallen below the intended treatment temperature. After a determined time below the intended treatment temperature, the user may be given an alert (text, icon, and / or sound) indicating that excessive cooling is present around the heating catheter. This notification may prompt the user to make adjustments to bring the heating element into improved contact with the vessel wall, such as by further emptying blood from the vessel.

[0129]

[0193] In certain implementations, a 120% power curve, such as that shown in Figure 32, is used as the maximum allowable energy delivery over time. For specific catheter and energy delivery system designs, similar curves can be created by measuring the average, median, or other typical energy delivery over time for several treatments in a representative system, where the heating energy is determined so that the desired treatment temperature is achieved and maintained. In further specific implementations, a time-dependent temperature relationship is obtained over several treatments in a representative system, and subsequent power-time relationships are determined and created to obtain similar time-dependent temperature relationships without the use of direct temperature measurements.

[0130]

[0194] In certain implementations, if the temperature of the heating element is too low for the level of power being delivered, or if the power level required to achieve the set temperature is too high (such conditions primarily indicate an excess of fluid around the heated area of ​​the energy delivery catheter instead of ideal heating of the vein wall), the user may be alerted by showing a graphical representation of the catheter with a graphical representation of fluid or cooling around the heated area. Alternatively, a message such as, for example, "Warning: Excess fluid, please empty vein" may be displayed.

[0131]

[0195] In certain implementations, the rapidity with which the treated vessel segment can be brought to the intended treatment temperature can be used as an indication of vessel wall contact and the absence of blood or fluid to cool the area. If the measured temperature is not achieved within a set time (e.g., for a set temperature of 120°C heated by a 7 cm 7 F heating element at a maximum power of 40 W, the temperature will typically register higher than 115°C after 3 seconds of heating), the user can be warned, heating can be automatically stopped, and / or the power level can be reduced to a level insufficient to coagulate blood within the vessel lumen.

[0132]

[0196] In certain implementations, temperature non-uniformity along the heating element can be indicated by comparing temperatures measured at different points along the heating element. Knowing whether the temperature is non-uniform can help prevent portions of the heating element from becoming too hot, which could cause damage to the device, and thus is beneficial for warning the user and / or automatically halting treatment or automatically reducing power to a lower level. If the electrical resistance of the heating element is temperature-dependent and, as a result, the temperature can be predicted by the measured resistance, e.g., a resistance temperature detector (RTD), the heating element resistance can be compared by the engine to the temperature measured by a thermocouple or thermistor via a resistance-to-temperature lookup table or algorithm. If the values ​​do not match a determined amount (e.g., by more than 10-20°C), it indicates that the heating element is not substantially uniform in temperature. In such cases, the user may be alerted by a sound / letter / code and / or the system may automatically reduce the power level or terminate treatment early or reduce the heating temperature to a lower level; in such situations, the user may be alerted to adjust the catheter or compression technique to create more uniform contact between the heating element and the vessel wall. An alternative method for determining if heating is not within predicted parameters is for the engine to compare the measured temperature (e.g., from a thermocouple, thermistor, or RTD measurement) to a known predicted temperature versus time lookup table or algorithm for similar energy delivery power-time relationships.

[0133]

[0197] In certain implementations, the resistance or impedance of the heating element is continuously measured by the engine to detect changes consistent with abnormal heating of the element or physical damage to the element. In such cases, treatment may be automatically stopped, power may be automatically reduced to a lower level, and / or the user may be alerted to the condition.

[0134]

[0198] In certain implementations, before treatment begins, the user may be notified that the tissue surrounding the energy delivery catheter heating element is being wetted with local anesthetic fluid; this condition may be detected by the energy delivery system engine when room temperature fluid is injected, as nearby fluid injection temporarily reduces the treatment vessel's temperature from body temperature to room temperature, and the engine can detect that temperature level. For example, a user notification tone or alert may be given after the catheter measures body temperature (approximately 34-39°C) for more than a predetermined time (e.g., 15 seconds) and then reduces to a lower temperature, such as room temperature (e.g., 24-28°C).

[0135]

[0199] In certain implementations, it is desirable for the user to know after treatment that the treated vessel has been substantially coagulated, with a contracted vessel diameter being the primary indicator. This can be observed under ultrasound visualization, but immediately after treatment, the vessel under treatment may be in a spasmodic state. One indicator that may be useful is a measurement of the force required to pull the energy delivery catheter (and heating element) to the next vessel segment. The force may be measured by a strain gauge applied to the catheter shaft or in the handle, or by a simple spring gauge measurement built into the handle. An acceptable force above a minimum acceptable threshold may be displayed as a visual cue and / or an audible cue may be presented.

[0136]

[0200] In certain implementations, Doppler ultrasound crystals are included within the energy delivery catheter to measure blood flow within the vessel lumen, providing a direct means of measuring or indicating blood flow or a desired lack of blood flow.

[0137]

[0201] In certain implementations, for an energy delivery catheter with a user-selectable heating length (e.g., 10 cm or 2.5 cm), the length of active heating can be selected by the user by pressing the touchscreen display, such as by pressing the image of the catheter and heating element. In this example, the default heating length can be the longer length, and when the screen image is pressed, a shorter length selection is made in the software and the image of the catheter shows the shorter active heating length. Further pressing of that area of ​​the screen (e.g., when heating is not active) toggles between the two active heating lengths. In one example, with three user-selectable heating lengths, pressing the screen image toggles continuously between the three heating lengths.

[0138]

[0202] In certain implementations, for an energy delivery catheter with a user-selectable heating length (e.g., a continuous range from 10 cm to 1 cm), the length of active heating can be selected by a slidable electrode contacting the proximal (or distal) end of the active heating length. The slidable electrode can contact the heating element along a range, such as 10 cm from the distal end of the element to 1 cm from the distal end. The effective length of heating can be measured by sensing the impedance between two electrical contacts of the heating element (e.g., a soldered connection at the distal end and a spring contact connection at a more proximal location) or by an electrically switchable selection. A user interface on the energy delivery control device 104 can display the effective heating length to the user and deliver the appropriate energy to heat a segment of that length, and can display the heating energy as an intensity per unit length of heating (e.g., W / cm).

[0139]

[0203] In certain implementations, the foot pedal has multiple switches, one switch serving to start or stop treatment and another switch serving to toggle a user-selectable heating length. In another example, the handle has two switches, one switch serving to start or stop treatment and another switch serving to toggle a user-selectable heating length. Alternatively, in examples where the handle has two switches, one switch can be used to start a longer heating length while the other switch can be used to start a shorter heating length, and in further implementations, pressing either of the two switches during energy delivery will immediately stop energy delivery.

[0140]

[0204] In certain implementations, the energy delivery controller plays a sound to indicate the treatment, such as identifying when it is heating to a set temperature and when it is heating to continue at the set temperature. In a further example, different changes in pitch or tone or tones indicate whether the user-selectable treatment length catheter is heating a shorter or longer active heating length.

[0141]

[0205] In certain implementations, for example systems in which the active heating length of the heating element is user-selectable (e.g., 10 cm or 1 cm), markings may be applied along the length of the heating element approximately equal to the length of the shorter heating length. A series of markings may be applied, where one visual cue (such as a series of dots) may be applied spaced approximately equal to the length of the shorter heating length and another visual cue (such as a series of lines) may be applied spaced approximately equal to the length of the longer heating length. This may be done to indicate where the shorter heating length is located or to facilitate local positioning and heating of the shorter heating length within the blood vessel. The markings may be created by printing (e.g., pad printing, screen printing, painting, or a designed color scheme on the tubing) on ​​the tubing where the coil heating element is located, provided that the space between the coils is wide enough to allow for the markings to be visible. Alternatively, the heating element or coil itself may be directly printed (e.g., pad printed) either in a pre-coiled configuration or after being loaded into the tubing. Alternatively, an ultra-thin layer of colored tubing can be placed over the heating element (e.g., PET heat shrink, approximately 0.0005 to 0.001 inches thick), with alternating pieces or short segments of different colors forming a pattern that facilitates gradual location for heating over shorter heating lengths. This marked outer layer can constitute the final outer layer covering the heating element, or it can be covered by an additional layer such as FEP, PTFE, or PET. Alternatively, a pre-printed layer of tubing can be shrunk over the heating element and / or over the tubing.

[0142]

[0206] In certain implementations, the heating element coil can be positioned on the shaft by directly coiling wire around the catheter shaft or section of tubing, by loosely sliding a pre-wound coil over the catheter shaft or section of tubing, or by using reverse rotation of the heating coil element to temporarily recoil a smaller pre-wound coil to a larger diameter than the one being slid over the catheter shaft or section of tubing to fit the coil over the catheter shaft or section of tubing. In certain implementations, the tubing can be rotated while pushing inside the heating coil so that the rotation of the tubing tends to widen the coil diameter to allow the coil to slide, wrap, or twist over the top of the tubing. In certain implementations, the heating coil can be rotated while loading onto the tubing so that the rotation of the coil tends to widen the coil diameter to allow the coil to slide, wrap, or twist over the top of the tubing. The heating element coil can have a shaped end configuration that interacts with the outer surface of the tubing to guide or steer the heating coil onto the shaft to a desired position.

[0143]

[0207] In certain implementations, wiring connections to the heating element can be made by soldering conductive wire to the heating coil after the heating coil is first loaded onto the shaft, or by pre-wiring (soldering or welding) the heating coil and then placing the wired assembly onto the shaft. In one configuration, holes or slots can be placed in the tube near the site where the wire will penetrate (e.g., by cutting with a hole cutter, skiving, or laser drilling) before the heating coil is loaded into place. In further specific implementations, after the wires are positioned in their final position within the holes or slots through the tube, adhesive can be applied to the holes or slots to protect the integrity of the tube against kinking if it is bent at that location. In one configuration, a slit can be made in one or more ends of the tube over which the coil assembly will be loaded, leaving room for the conductive wire to enter the lumen of the tube near the heating coil end. In an example, a passageway within the tube into which the coil assembly is loaded allows one or more conductive wires to be positioned directly below the heating coil so that multiple conductive wires can enter the lumen of the tube near the distal end of the coil assembly. In another example, a long slit is made in the tube below the heating coil to allow for wire passage or placement, and a molded part is slid inside the tube below the coil to provide mechanical support and prevent the coil-loaded assembly from easily kinking or otherwise bending in an undesirable manner.

[0144]

[0208] In certain implementations, for example systems in which the active length of heating is user-selectable, the electrical circuitry to achieve this selection can be created by attaching conductive wire to each end of the heating coil and to points midway along the heating coil (e.g., conductive wires attached 0 cm, 2.5 cm, and 10 cm proximal, measured from the distal end of the coil). The midway wire can be directed into the lumen of the tube at that location, or it can be located directly below the coil, above the coil, or between coil turns until it reaches a more favorable location for entering the lumen of the tube, such as near the distal end of the heating coil. An insulating layer must exist between the heating coil and any conductive wires physically located across adjacent coils; that insulation can be on the conductive wire itself, on the heating coil itself, in a layer of material generally between them, or a combination thereof.

[0145]

[0209] In certain implementations where the active length of heating is user-selectable, the shorter length of wiring connection (e.g., 2.5 cm proximal to the distal end of the heating coil) is made using smaller wire than the wire connecting the two ends of the coil. This smaller wire can continue all the way through the handle and cable to the energy delivery controller, or it can be smaller only along a portion of its length, such as from the 2.5 cm location to the distal end of the coil. In further specific implementations, the shorter length of wiring connection between the 2.5 cm location and a point near the distal or proximal end of the heating element is ribbon wire that is 2 to 8 times wider than its thickness.

[0146]

[0210] In certain implementations, the shape of the heating element is modified before, or preferably after, loading onto the catheter tube so that the cross section of the heating element is not round (as is typical), but instead has flat or recessed areas along all or a portion of its length to leave space for the outer wire of the coil while maintaining a minimal profile for the catheter through a circular hole, such as in an access sheath.

[0147]

[0211] In certain implementations of two-piece heating coil assemblies, the proximal coil segment is wired with conductive wire at both ends, with or without a thermocouple placed at the distal end of the proximal coil, and then the distal coil segment is added and electrically connected to the distal end of the proximal coil (at the proximal end of the distal coil), with the conductive wire connected at the distal end of the distal coil. This method can be facilitated by a passage or slit in the underlying tubing that extends from the distal end of the tubing to the junction between the proximal and distal coils; that type of slit in the distal end of the tubing can be supported by adding an underlying tubing with slits in opposite directions that are inserted so that the two slits extend in opposite directions from the point where the assembly wire enters the body of the catheter.

[0148]

[0212] In certain implementations, the heating element is constructed using a high-temperature resistant shaft material such as polyimide, polyetheretherketone (PEEK), ULTEM®, or silicone in an assembly designed to withstand a full range of heating temperatures (e.g., room temperature, approximately 25°C, up to approximately 200°C or higher), and the heating element / shaft assembly is then connected to a more economical material (e.g., 72D PEBAX®, nylon) to make up the majority of the catheter shaft length. The connection between these two shaft sections can be by adhesive (e.g., UV-cured acrylic adhesive, UV-cured cyanoacrylate, moisture-cured cyanoacrylate, two-part epoxy, or water-soluble adhesive) or by melt processing, which is facilitated when the polyimide or other high-temperature material has an integral outer layer of a corresponding melt-processable compatible material.

[0149]

[0213] In certain implementations, a way to increase the tensile strength of a catheter assembly can be to include a pull element within the catheter shaft. For example, a wire (e.g., stainless steel, NiTi, copper, etc.) can be attached to the heating element or to the tubing near the heating element on one end and to the handle on the other. This wire can be electrically connected to the coil, providing a conductive connection with that end of the coil, or it can be electrically insulated so that it does not connect as a functional part of the electrical circuit. If the wire is intended to be conductive, conduction can be improved by plating (e.g., gold, copper) or cladding.

[0150]

[0214] In certain implementations, the wires running through the catheter shaft from the handle area to the heating element area are Siameseed into a bundle to facilitate wire loading. The Siamese bundle can be flat with side-by-side wires or multi-layered. A color-coded configuration, such as a flat bundle with a uniquely colored line at one end or multiple colored wires, can aid in identifying the correct wire connections during catheter assembly.

[0151]

[0215] In certain implementations, the visibility of the catheter when viewed through body tissue with ultrasound can be improved by providing a textured surface (i.e., surface structure) to improve the reflection of sound waves, or by providing trapped air pockets or passages within the device. Thus, Figures 35A and 35B depict an example heated catheter tube designed to facilitate visibility of the heated catheter with ultrasound. Methods for achieving a textured surface on the heated catheter tube 112 include chemical etching, grit blasting, laser machining, sanding or scraping, crimping in a patterned die, or molding key components with the desired texture in an injection mold. Methods for creating trapped air pockets 3504 include leaving spaces between heating coils bridged by an outer layer of material such as a smooth outer jacket; extruding a tube with multiple lumens (such as an array around a central lumen); extruding a tube with multiple grooves 3502 along the outside and then covering the outside with heat shrink tubing to form bridges across the grooves that trap the air in the small passages; laser machining pockets or grooves into the surface of the tube and then covering the machined areas with thin heat shrink tubing so that the bridges trap the air in their shape; and performing a heat treatment with multiple wires parallel to the axis of the tube and then withdrawing the wires leaving multiple parallel lumens that are then fluid-tight at two ends or in succession to create the trapped air passages or pockets.

[0152]

[0216] In certain implementations, multiple cube corner reflectors are laser machined into the surface of the shaft tube onto which the coil is loaded, or into a short section of tube that is slid into place on the shaft, similar to how marker bands are for visibility under x-ray or fluoroscopy, or into the smooth outer jacket that covers the heating coil. The physical dimensions or surface roughness of the trapped air to improve ultrasound contrast (echogenicity) should ideally be approximately the same as the wavelength of the sound used for imaging. For example, a 10 MHz ultrasound probe uses a wavelength of 0.006 inches in water (15 MHz = 0.004 inches, 6 MHz = 0.010 inches).

[0153]

[0217] In certain implementations, the energy delivery catheter may be powered by a pair of wires (and possibly stored power in a capacitor built into the energy delivery catheter handle or cable), and then use wireless communication (e.g., BLUETOOTH® or ZIGBEE®) between the energy delivery catheter and the energy delivery controller 104 for catheter identification, temperature and / or resistance / impedance feedback, and start / stop commands. In certain implementations, the energy delivery system is miniaturized and integrated into the handle of the energy delivery catheter.

[0154]

[0218] In certain implementations, the catheter electronics and connector system for the two- or three-wire cable are combined into an application-specific integrated circuit (ASIC) to minimize cost and components within the catheter, such as within the catheter handle. In further particular implementations, such an ASIC includes a logic engine (e.g., a microprocessor), memory storage, noise filtering, and means for switching and directing power. In further particular implementations, the ASIC includes input facilities for multiple unique temperature sensors. In further particular implementations, the ASIC includes input facilities for multiple user interaction buttons. In further particular implementations, the ASIC has the ability to direct power into multiple energy delivery features of the medical device, independently or simultaneously. In further particular implementations, the ASIC has the ability to activate several user interaction devices, such as LED lights or ultrasound crystals. In further particular implementations, the logic board or ASIC is powered from a remote power source, such as within a controller, or by a wirelessly charged battery. In a further specific implementation, the ASIC includes a charge pump that increases the voltage to a transistor (e.g., a MOSFET) that connects the catheter heating element to the power delivery circuit, the charge pump being used to overcome the natural decrease in resistance over time that results from battery use.

[0155]

[0219] In certain implementations, surgical data storage from several recent treatments can be wirelessly transferred to a memory module built into the power supply. The surgical data storage from each treatment can be relayed to a wireless data device such as a laptop computer, tablet computer, or cell phone. Live gauges and / or start / stop buttons can be interactively displayed on such a wireless device.

[0156]

[0220] In certain implementations, information about the treatment, such as the date and time of the treatment, how many heating cycles were completed, the total time of energy delivery, and the total energy delivered per cycle (e.g., J / cm), may be stored within the energy delivery controller 104. Other information, such as temperature and power levels versus time increments, the measured resistance or impedance of the energy delivery catheter heating element circuitry versus time increments, and alerts or status updates (whether displayed to the user), may also be stored. This data storage may include the most recent usage of 10 or more energy delivery catheters used with the energy delivery controller 104, as raw or encrypted data storage.

[0157]

[0221] In certain implementations, the energy delivery system is configured to accept communication from a footswitch (pneumatic, air-filled tube-activated, or electric, such as a direct cord, or a cordless information link such as BLUETOOTH® or ZIGBEE®) (in addition to or instead of a switch on the handle of the energy delivery catheter) to provide a signal to start or stop treatment. A pattern of presses, such as a double press, may be required to start treatment, or the energy delivery controller 104 may require that the pedal be held down for at least the first 1-2 seconds of each treatment, or pressing down the foot pedal may mirror the effect of pressing a handle button.

[0158]

[0222] In certain implementations, the energy delivery system is configured to electronically interact with the fluid delivery pump, such as to control the rate at which the pump delivers fluid or to monitor the volume of fluid delivered by the pump. For example, the energy delivery controller 104 can accept input about the starting volume and / or concentration of the fluid to be attached (or provided electronically with some or all of that information) and then display an indication of how much fluid remains to be delivered while the pump is delivering the fluid. This can help the user know that they have enough fluid remaining to cover all of the intended body tissue anesthetic effect, rather than injecting too much at the start and not having enough volume left for the final location.

[0159]

[0223] In certain implementations, the energy delivery system is configured to also carry data over the same conductors that provide the heating energy current to the heating catheter. Examples of data carried by the energy delivery system include the open / close configuration of the start / stop button, a device identifier, historical information about connected device usage, and / or temperature. In this manner, electrical conductors between the heating catheter and the energy delivery control device 104 can be minimized. Energy can be delivered within the high frequency band of the electromagnetic spectrum, with the degree of heating modulated by amplitude modulation, while one or more data signals are also carried at higher and / or lower frequencies. Energy can also be delivered as constant amplitude direct current energy, with the degree of heating modulated by interrupting the current in successive start / stop intervals of various lengths (pulse width modulation), while one or more data signals are also carried within the pattern of the start / stop intervals.

[0160]

[0224] In certain implementations, a Wheatstone bridge is connected to the thermocouple conductors to assist in energy measurement. The Wheatstone bridge may be located within the energy delivery controller 104. The Wheatstone bridge may also be located within the heating catheter, such as within the handle of the heating catheter. An isothermal junction of one or more thermocouple leads may be located within the heating catheter, such as within the handle of the heating catheter. A reference temperature sensor, such as an integrated circuit temperature sensor, may be located within the isothermal junction of the heating catheter. The foregoing method of reference junction compensation within the heating catheter has the direct advantage of not requiring the dissimilar metals of the thermocouple to extend from the heating element to the energy delivery controller 104, and can facilitate the transport of data between the heating catheter and the energy delivery controller 104 via a minimal number of wires.

[0161]

[0225] Being able to control how many times a device can be used to treat a patient can be beneficial, as devices are developed to provide good treatment at the least possible cost, and little extra effort is made to ensure the device will withstand many uses. This has been commonplace in the endovenous laser industry for many years, among other single-use medical devices.

[0162]

[0226] In certain implementations, an electronic control engine within the heating catheter is used to record data regarding the status of use of the heating catheter and communicate that information to the energy delivery controller 104. In one example, an indicator of the time of first use or elapsed time of use may be stored within the heating catheter, such as in an integrated circuit within the heating catheter handle or cable assembly. In this manner, the energy delivery controller 104 can determine, via the usage control engine, whether the heating catheter has been used previously in a procedure and how much time has passed since that use, allowing the energy delivery controller 104 to enable use of the heating catheter within an acceptable time period for treating a single patient in one treatment procedure, such as over a 1-4 hour period from the start of the first treatment to the start of the last treatment. This is advantageous in that if the heating catheter is implanted but the patient's treatment is canceled before treatment begins (and before the heating catheter is rendered unsterile), the catheter can still remain sterile and be used later on a replacement patient.

[0163]

[0227] In certain implementations, the electronic control engine within the heating catheter is configured to cooperate with the energy delivery controller 104 to enable use of the heating catheter for a predetermined number of patient treatments. A typical multiple-use scenario for an intravenous laser allows use of the laser fiber for up to five patient treatment sessions. In one example, the electronic control engine and energy delivery controller 104 work together to enable three to five treatment sessions, where each treatment session can be defined as a group of treatments within an allowable time window, such as one to four hours, or each treatment session can be defined as the treatment of a single patient, with the first treatment starting after the previous time interval has elapsed, then triggering the start of successive treatments with a new time interval. Once all allowable time intervals have been completed, the electronic control engine and energy delivery system no longer enable further treatments.

[0164]

[0228] In certain implementations, the heating catheter electronic control engine records or counts the applied treatments, and the energy delivery controller 104 allows treatments up to a threshold number of treatments. In an example, for a heating element length of 10 cm, the threshold number of treatment cycles may be in the range of 10 to 30 cycles.

[0165]

[0229] In certain implementations, the heating catheter electronic control engine records the elapsed time that the heating catheter has been implanted into the energy delivery control device 104. In examples, after 2-6 hours of implantation time, the electronic control engine and energy delivery system no longer enable treatment.

[0166]

[0230] In certain implementations, data regarding heating catheter usage can also be useful in diagnosing reported malfunctions of the heating catheter. It is useful for storing memory within the heating catheter's electronic control engine, including the identification of the energy delivery controller 104 used for treatment, the start and stop times of each treatment, and a measure of the energy delivered during each treatment. Records of quality control testing as part of the manufacturing process are also useful. This data is ideally encrypted to prevent unauthorized changes to the data.

[0167]

[0231] In certain implementations, the electronics in the handle of the heated catheter, including a battery to power the logic engine and communications, are configured to facilitate activating the logic and communications system after the battery in the catheter assembly is depleted. In further certain implementations, the circuit board pads or other conductors are configured to be reachable by external probe conductors through the body of the handle, such as by removing the button cover and contacting the appropriate conductors through a window that previously housed the button cover.

[0168]

[0232] In certain implementations, data from a sampling group of procedures may be collected on a memory module within the energy delivery controller 104. This data may be transferred to a company for storage in a company memory module. Users may receive compensation for sending this data, such as product rebates, cash equivalents, or other consideration, or the data may be collected without compensation. The company may analyze this and other data, collectively or individually, to determine a unique, average, or intermediate energy delivery profile. If the data is collected from an energy delivery catheter with temperature feedback, the determined energy delivery profile is one typically required to achieve and maintain the same desired temperature. The energy delivery profile may also be usable with a similarly constructed (or having equivalent thermal characteristics) energy delivery catheter that does not include temperature feedback to achieve similar tissue ablation characteristics with a simpler and potentially less costly energy delivery catheter design. The user may be required to specify what type or size of vessel is being treated so that energy delivery profiles can be developed for various vessels. In such cases, the user can select on the energy delivery control device 104 which type of vessel is being treated so that the system can associate the correct energy delivery profile with the treatment at hand.

[0169]

[0233] In a specific implementation, a similar energy delivery system is used to treat benign prostatic hyperplasia (BPH) via transurethral needle ablation (TUNA). In such a system, radiofrequency needle(s) are placed through the urethra into the lateral lobe of the prostate. The needles are energized to increase the temperature of the target area of ​​the prostate and induce thermal necrosis (local tissue death). In a further specific implementation of the procedure, tissue is heated to 110°C with RF power delivered at 456 kHz for approximately 3 minutes per lesion, causing coagulopathy. In an alternative specific implementation, the needles are configured to include a heating element that transfers heat to the surrounding prostate tissue. Such a configuration may include the minimized wiring serial communication design described above.

[0170]

[0234] Figures 33A-33C depict exemplary techniques that can be utilized to promote uniform heating within the venous lumen. In certain implementations, a similar energy delivery system is used to treat endometriosis by endometrial ablation. In such systems, uterine electrosurgery or radiofrequency ablation is achieved by inserting a specialized instrument into the uterus that passes an electrical current that eventually heats up and destroys the endometrial layer. Exemplary instruments can include a wire loop 3304 depicted in Figure 33C, a spiked ball, a triangular mesh, a roller ball, or an inflatable balloon 3302 depicted in Figure 33B, or wings 3300 depicted in Figure 33A. In a further specific implementation, the generator delivers up to 180 W at 500 KHz to ablate the endometrium to a uniform depth over a programmed treatment cycle of 40-120 seconds. In an alternative further specific implementation, heating of the inflatable balloon 3302 is achieved to maintain a surface temperature of approximately 70-75°C during a 4-minute treatment session.

[0171]

[0235] 33A-33C can also be used to promote uniform heating of the heating catheter 102 by properly centering the heating elements 106 within the venous lumen. Additionally, FIGS. 34A and 34B depict another device or technique for promoting uniform heating. In this example, the heating elements 106 are provided on two parallel tubes that are bent or curved away from each other, as shown in FIG. 34A, and that are stationary and parallel next to each other when force is applied to the heating elements 106 from the side. Thus, within the venous lumen, each heating element 106 will press against the side of the venous lumen, ensuring uniform heating, and will press against each other when they encounter, for example, a smaller area.

[0172]

[0236] In certain implementations, similar energy delivery systems are used to treat cancerous lesions such as those in the liver, lung, breast, kidney, and bone, in which heat is typically applied directly within the tumor, such as through a needle having a heating element or having one or more electrodes for delivery of radiofrequency energy, or by multiple needles delivering RF energy.

[0173]

[0237] In certain implementations, similar energy delivery systems are used to treat back pain, such as by radiofrequency neurotomy, in which heat is applied to targeted nerve tracts to block the transmission of pain signals to the brain. A needle or heating element carrying one or more electrodes is directed through a gap in the spine into the treatment area of ​​inflamed nerve tissue.

[0174]

[0238] In certain implementations, similar energy delivery systems are used to treat Barrett's esophagus, a condition in which normal squamous epithelium is replaced by specialized columnar epithelium known as intestinal metaplasia in response to inflammation and damage caused by gastroesophageal reflux disease (GERD). In this treatment, heat is applied directly to the Barrett's lining of the esophagus. In further specific implementations, the energy delivery system works in conjunction with an ablation catheter having an inflatable balloon with a plate-based heating element or electrodes.

[0175]

[0239] An exemplary manufacturing assembly step may include cutting a length of main shaft tubing (e.g., polyimide tubing). External shaft markings may be printed (e.g., laser etched or pad printed, alternatively pad printed after a surface treatment such as plasma) onto the main shaft tubing and cured and dried. The shaft markings may include sequential markings for user alignment, as well as machining guide markings such as the locations of heating element ends and through-holes.

[0176]

[0240] Drill (e.g., laser machining or sharp hole cutter), punch, or skive through holes for the wires into the area where the heating element will be located. Clean or polish at least the soldering location on the heating element to remove oxidation, such as by sanding, grit blasting, or acid etching (which may be included in acid soldering flux). In one example, a tinning process is applied to the heating element soldering location, such as using silver solder and hydrochloric acid flux. Clean or neutralize the heating element. Load the heating element into the main shaft tube, aligning the element with the machining guide markings (if present). If the coil heating element is smaller than the shaft tube and, as a result, cannot be slid straight over the tube, rotate the heating element or shaft (or counter-rotate the two relative to each other) in a direction that widens the coil to allow it to slide over the tube.

[0177]

[0241] The coil heating element can be snugly fitted into place by counter-rotating the two coil ends and tightening the coil onto the shaft tube. Connecting wire (e.g., 28-32G copper "magnet wire") can be soldered to the appropriate location on the heating element; exemplary soldering locations include side-wrapping the last 1 / 4-1 / 2 coil with copper wire at each end, or sandwiching copper wire between portions of the last two coils. Prior to soldering, remove the insulation from the wire ends, such as by cutting, brushing, or scraping the wire, leaving approximately 2-5 mm of bare wire exposed. The connecting wire can be threaded through the nearest through-hole to the proximal end of the shaft. A thermocouple (or thermistor) can be threaded through a through-hole near the temperature sensing location, with the thermocouple junction (or thermistor bulb) positioned between the coil turns to prevent coil-to-coil shorting (prevented by an air gap or insulating layer such as PET). The thermocouple is fixed in place, such as with cyanoacrylate glue.

[0178]

[0242] Slide the smooth outer jacket over the heating element, align it to cover the desired area, and heat-shrink it to tightly cover the heating element. Slide the guidewire lumen through the inside of the shaft tube, aligning it so that the distal end of the guidewire extends approximately 1.0–3.0 mm beyond the distal end of the shaft tube. Apply an adhesive, such as UV-cured acrylic or cyanoacrylate, to the distal tip to bond the two tubes together, providing a rounded, atraumatic tip and maintaining full access to the guidewire lumen inner diameter.

[0179]

[0243] Consequently, the above steps can be taken for another implementation of the heating element, but this time a third wiring connection can be added to the heating element at a point along its length (e.g., 2.5 cm from the distal end of the coil). Additionally, instead of using a through-hole for the thermocouple to enter the shaft tube near its sensing location, the thermocouple wire is wrapped in a coiled fashion in the space between consecutive heating coils. Note that this same coil-space winding can be used for the third wiring connection as seen in exemplary heating element subassembly B, and the two windings can be side-by-side within the coil space, or run in opposite directions along the coil space, or a combination of the two.

[0180]

[0244] In another example, instead of using a through-hole for the thermocouple to enter the shaft tube near its sensing location, the thermocouple wire is laid over the heating coil so that it is trapped in place between the heating coil and the smooth outer jacket. It is important that sufficient electrical insulation cover the thermocouple wire to prevent shorting the heating element coil. The strip of insulation between the thermocouple and the coil can be used along the entire length the thermocouple wire covers the heating coil, or simply along the end of the thermocouple wire, in which case the end is stripped to create the joint. Alternatively, the coil can be coated with shrink tubing or parylene or a similar coating to prevent electrical contact with the thermocouple. One way to align the insulating film strip is to include two holes or straps near one end of the strip through which the thermocouple wire can be passed to extend past the area of ​​the thermocouple junction and hold the strip in place.

[0181]

[0245] Another way to align the strip is to glue it, such as with cyanoacrylate. Note that this same wire configuration on the coil can be used for the third wiring connection as seen in exemplary heating element subassembly B. One way to position the thermocouple in the desired location before heat-shrinking the smooth outer jacket in place is to thread a filament (cotton or polymer or other) through the location of the thermocouple junction, and then secure, such as with tape, the thermocouple wire to one end of the coil assembly and the filament to the other end to hold the junction in place while the smooth outer jacket is shrunk in place, trapping the thermocouple wire. One way to ensure that the wire profile on the heating coil does not protrude completely along the outside of the heating coil is to deform the heating coil inward along the path of the thermocouple wire, such as by crimping the heating coil (possibly including the tube in which it is loaded) into a die crimp fixture.

[0182]

[0246] Instead of placing a thermocouple between the heating coils, a thermistor is placed directly beneath the heating coil, preferably in direct contact with the inner surface of the heating coil. One way to position the thermistor is to cut a window in the main shaft tube so that the thermistor axis is parallel to the main shaft tube axis and one side of the thermistor is flush with or slightly above the surface of the main shaft tube. One means of holding the thermistor in place is to cut a window in the main shaft tube, leaving one or more straps that invert into the lumen of the main shaft tube to support the thermistor and prevent it from falling unsupported into the lumen of the main shaft tube. Another means of holding the thermistor in place is to place a molded plug next to or beneath the thermistor to prevent it from falling unsupported into the lumen of the main shaft tube. A thin layer of heat shrink tubing can be placed over the main shaft tube to hold the thermistor in place before loading the heating coil.

[0183]

[0247] If the heating element subassembly does not include the entire length of the catheter shaft to be inserted into the patient, an additional length of proximal shaft tubing (e.g., 72D Pebax, polyimide, or other material) with printed shaft markings is glued to the proximal end of the main shaft tubing. This glue can be an adhesive such as cyanoacrylate or UV-cured acrylic, or it can be heat-bonded. An exemplary heat bond in place is to melt the Pebax proximal shaft tubing to the polyimide main shaft tubing with a thin Pebax outer layer.

[0184]

[0248] A cable assembly (with an electrical cable having a bayonet connector for the energy delivery control device 104 on one end and a cable anchor and handle circuit board assembly on the other end) is assembled with the A-side of the handle assembly. A strain relief body is placed over the proximal end of the catheter or heating element assembly. The catheter of the heating element assembly is then glued to the A-side of the handle assembly. Wires from the catheter or heating element assembly are electrically connected (e.g., soldered) to the handle circuit board assembly, and exposed electrical surfaces are potted with an insulating material such as UV adhesive. Button component(s) may be assembled into the B-side of the handle assembly (or button functionality may be designed into the deflection portions of one or both of the A-side and B-side), and the A-side and B-side of the handle assembly are mated together. The two halves may be mated together by a press-fit post-and-hole configuration, adhesive bonding, solvent bonding, or ultrasonic welding. The strain relief body may be mated to the handle assembly by any of the methods listed above.

[0185]

[0249] The catheter may be tested to ensure all electrical connections are effective, such as by measuring a baseline temperature with an included temperature sensor, measuring electrical resistance across the heating element, and measuring the validity of the identification components. The heating catheter electronic control engine may be programmed with codes, conditions that enable treatment with the user's energy delivery system, and possibly measured data such as test records and / or test results.

[0186]

[0250] The catheter can be inserted into a coiled protective tube, such as polyethylene, with the handle fitting directly into the end of the tube or into a side or intermediate holder adjacent to the tube. The electrical cable can be coiled to fit within or next to the protective coil area. This coiled assembly can be slid into a protective pouch, such as TYVEK® / MYLAR®, and the open end of the pouch is heat sealed. This pouch, with appropriate labeling covering one or more of the end flaps, is placed into a chipboard carton along with printed instructions.

[0187]

[0251] In certain implementations, a catheter having a heating element has an expandable / collapsible feature intended to keep the heating element portion of the catheter more centered within the treatment vessel lumen when the vessel lumen collapses flat with the heating element within the vessel lumen (such as by external unidirectional compression of surrounding tissue). In certain implementations, the heating element portion of the catheter is curved in a pattern that provides a flattened, serpentine orientation of the heating element along the vessel lumen when the vessel lumen collapses flat. In certain implementations, the heating element portion of the catheter is curved in a helical orientation to help the heating element contact the surface of the vessel lumen when the vessel lumen is much larger than the size of the heating element.

[0188]

[0252] To minimize the number of conductors in a device cable assembly, with a correspondingly reduced number of conductors in the device connector, one particular implementation consists of three conductors: a power conductor, a communication conductor, and a shared return (ground) for power and communication. Sharing a return conductor for high levels of current causes a voltage drop across the return conductor, which disturbs the reference voltage of the communication signals.

[0189]

[0253] In certain implementations, specialized circuitry (a combination of a filter, discriminator, and Schmitt buffer) is used to recreate the original shape (information) of the communication signal. A non-zero gain low-pass filter filters out noise components induced in the communication cable by changes in current in the power conductors. The discriminator recreates the main shape of the signal. The Schmitt buffer further transforms the signal so that it meets digital signal requirements such as signal level and slew rate.

[0190]

[0254] In a simulation of this particular implementation, the signal shapes at particular stages of the circuit are shown. Trace 1 shows the input (communication) signal conveying the desired information. Trace 2 shows exemplary noise (both high and low frequencies) generated by the environment, e.g., current changes in the power conductors. Trace 3 shows a signal with the combined effects of the signal from Trace 1 and the noise from Trace 2. Trace 4 shows the shape of the signal after a low-pass filter removes the noise and amplifies the signal; this signal exhibits improper timing and slew rate, as well as parasitic glitches. Trace 5 shows the signal at the output of the discriminator; the glitches have been removed, but the signal still exhibits an improper slew rate. Trace 6 shows the signal at the output of the Schmitt buffer; here, the signal exhibits sufficient quality to capture the information it conveyed. Comparing signals 6 (output) and 1 (input) shows proper communication of the signal information with slight degradation in timing, and the voltages are intentionally different to be consistent with the transmitting and receiving systems.

[0191]

[0255] It will be understood that many of the above design features, variations, and configurations for generator operation, thermal treatment catheter, or energy emitting probe configurations, and other such variations for using tip-sleeve, tip-ring, tip-ring-sleeve, tip-ring-ring-ring-sleeve, tip-ring-ring-ring-ring-sleeve, or other types of so-called blind or "headphone jack" connectors, can be advantageously applied to the alternative single thermal segment catheters that follow.

[0192]

[0256] 36A is a perspective view of an embodiment of a heated segment treatment catheter 3600 having a push button handle 3602 and a TRS connector 3604. The handle, cable, and TRS connector may be configured as described above with the multiple segment selectable length catheter embodiments. Additionally, the generator described above includes hardware and software to recognize and interact with a single thermal treatment segment.

[0193]

[0257] The treatment catheter may be a single-segment heating catheter or a multi-segment selectable-length heating catheter. The heating catheter may have a shaft with an insertable length L of 40 cm to 100 cm with a resistive coil heating element ranging in active heating length HL from approximately 0.5 cm to 10 cm. In some embodiments, the heating element may be up to 20 cm or longer in length. The catheter may be single-use and disposable. Circuitry (e.g., a handle board) controlling the heating element and / or temperature sensing may be disposed within the handle. In some embodiments, the catheter diameter may be approximately 2.0 mm, intended for use with a 6F vascular access system, although the catheter may also have a smaller 5F configuration. The treatment catheter is designed and configured for operation with a generator (such as generator 104 described above) for delivery of thermal therapy at a desired setpoint temperature (e.g., 130°C) that may be non-adjustable or adjustable during delivery.

[0194]

[0258] In some embodiments, the catheter may include a thermocouple or temperature sensor configured to sense or measure the temperature of the coil heating element during treatment. In further embodiments, delivery of thermal therapy at a desired setpoint temperature may be controlled in a feedback loop by the generator using a signal from the heating coil sensor / thermocouple. Figure 36B is an enlarged cross-sectional view of the catheter of Figure 36A showing the rounded distal tip 3606, the heating coil segment 3608 within the catheter shell 3610, and the location of the temperature sensor (e.g., thermocouple) 3612 within the heating coil segment. As seen in this view, the heating coil segment is positioned at the very distal end of the treatment catheter, retracted only by the rounded, atraumatic tip. The temperature sensor is shown in a location within the heating coil approximately halfway between the proximal and distal ends of the heating coil segment. However, it should be understood that the temperature sensor may be placed elsewhere within the heating coil segment.

[0195]

[0259] As explained above, the temperature inside the catheter is measured by a temperature sensor or thermocouple located in the heating coil element. Figure 37 is a schematic diagram of a circuit 3700 for a catheter in which the catheter thermocouple 3701 is galvanically isolated from the circuitry for powering the heating element 3703. Galvanic isolation of the thermocouple amplifier in the handle eliminates the possibility of surgical error caused by fluid ingress into the catheter through a contaminated catheter surface.

[0196]

[0260] The thermocouple wires of the catheters described herein may be insulated by an insulating coating, and an additional sealing tube may be placed over the thermocouple junction. Despite these measures, small damage may still be found on the coating as a result of the stresses the thermocouple wire is subjected to during production. The coil heater element itself is insulated only externally by the catheter shell (e.g., FEP plastic layer).

[0197]

[0261] Typical signal values ​​for a properly operating thermocouple do not exceed a few millivolts. The voltage powering the catheter varies from a few volts to approximately 20 V (depending on the heater type and the phase of the heating cycle). If the catheter surface becomes contaminated (e.g., by puncture with a needle while injecting tumescent fluid during intravenous therapy), conductive fluids (e.g., saline and blood) can penetrate into the catheter, creating a conductive path between the uninsulated heater coil winding and damaged insulation of the thermocouple (e.g., through damage to the thermocouple wire coating). When the heater is energized, the voltage powering the catheter biases the thermocouple signal, resulting in an erroneous, excessively high temperature reading. This can occur because both the thermocouple signal amplifier and the power circuit energizing the catheter share the same reference ground. An erroneous, excessively high temperature reading causes the heating cycle to be immediately terminated and an over-temperature error to be returned by the generator.

[0198]

[0262] To eliminate the possibility of the errors described above, the thermocouple amplifier 3702 (and optionally, the secondary thermocouple amplifier 3704) illustrated in FIG. 37 is galvanically isolated from reference ground using an isolation amplifier powered from a voltage source that is galvanically isolated from the handle power circuit. In this way, the thermocouple and heater do not share the same reference ground, and even if the catheter surface and thermocouple wire coating become contaminated and conductive fluids seep into the catheter, there is no return for the signal to cause an erroneous temperature reading, and therefore the measured temperature value remains correct. Because the thermocouple voltage is no longer referenced to the handle substrate ground potential, the thermocouple reading remains valid even if there is a short circuit between the thermocouple and the heater.

[0199]

[0263] FIG. 38 illustrates one embodiment of a multi-segment selectable length heating catheter 3800 having heating coil segments 3808 that may include multiple user-selectable heating lengths. The heating catheter may be configured to connect to a generator as described herein. In some embodiments, the heating catheter includes a TRS-type connector configured to plug into a generator socket. As shown in FIG. 38A , the illustrated embodiment may include three separate heating lengths HL1, HL2, and HL3. In some embodiments, HL1 may have a length ranging from approximately 0.5 cm to approximately 5 cm, HL2 may have a length ranging from approximately 2.5 cm to 20 cm, and HL3 may have a length ranging from approximately 5 cm to 40 cm. In one particular embodiment, HL1 may include a length of 2.5 cm, HL2 may include a length of 6.25 cm, and HL3 may include a length of 10 cm. However, it should be understood that the lengths of the heating lengths may vary depending on the application or target anatomy. For example, in another embodiment, HL1 may have a length of 2.5 cm, HL2 may have a length of 10 cm, and HL3 may have a length of 20 cm. Similarly, fewer or more than three heating lengths may be incorporated into the catheter using the same principles used herein. The catheter may further include a temperature sensor (e.g., a thermocouple) 3812 positioned within the HL1 heating length. The catheter may include multiple leads L1, L2, L3, and L4 configured to excite the heating coil segments comprising the heating lengths HL1, HL2, and HL3. For example, to excite HL1, a DC current may be applied to leads L1 and L2. Similarly, a DC current applied to leads L1 and L3 may excite HL2, and a DC current applied to leads L1 and L4 may excite HL3. The leads may include, for example, 30-32 AWG wire.

[0200]

[0264] In some embodiments, the catheters described herein are single use or limited use. As such, the systems herein, including the generators, may implement a number of methods to prevent rework or reuse of catheters after they have been used.

[0201]

[0265] First, each catheter can be "branded" with its type and programmed during production. The branding process can include burning information into the catheter's flash memory (e.g., as firmware in the handle board). The branding serves many purposes, including allowing the controller / generator to identify the type of catheter shaft inserted into the catheter handle. As described herein, many different catheter types can be implemented within the system. For example, catheters can include single heating element shafts, multi-length heating element catheter shafts, short catheter shafts, long catheter shafts, etc. By branding the catheter type into the catheter's handle board, the controller / generator can automatically and accurately identify the catheter type when the catheter is plugged into the controller and automatically configure the controller / generator to accurately control that particular catheter type.

[0202]

[0266] In some embodiments, marking each catheter also includes storing a catheter-specific production lot / serial number to enable product traceability. For example, if manufacturing defects or problems are later identified with a particular production lot of catheters, these defective catheters can be easily identified and / or flagged by a control / generator upon attempted use.

[0203]

[0267] A region code may also be engraved into the handle substrate of the catheter, allowing for regionalization. For example, a particular region or country may only approve a subset of available catheter types. By imprinting the region code on the catheter, only approved catheter types can be used with generators in those particular regions. For example, a catheter type (e.g., a 20 cm long, multiple heating element catheter) may be approved for use in the United States but not in Europe. Imprinting the region code on these catheters will allow use of this particular catheter only in the United States but will prohibit or prevent use if the catheter is plugged into a European generator / controller.

[0204]

[0268] Embedding the catheter with code read protection further hinders the use and production of counterfeit catheters. Because the catheter is engraved with the code read protection in firmware directly onto the handle board, the embellishment scheme prevents reverse engineering. Because the catheter cannot function in the field without the embellishment, counterfeit catheters without the embellished handle board cannot be used with the controller / generator. Because the embellishment is done by software / firmware, the catheter is provided with a certificate without the need for hardware modifications.

[0205]

[0269] In addition to the catheter type imprinting, the imprinting may further include limitations on catheter use, including a therapy cycle number usage limit, a time usage limit, or a battery charge usage limit. For example, the catheter handle board may be imprinted with a therapy cycle usage limit (e.g., a 56 therapy cycle usage limit). The number may be stored in the catheter handle board as firmware. Because the number is stored locally on the catheter handle board, removing power (e.g., removing or replacing the catheter battery) does not affect, change, or reset the therapy cycle number. When the catheter has been used for the entire therapy cycle limit, the catheter may become non-functional. The catheter may also be imprinted with a time usage limit (e.g., a maximum usage of 240 minutes). As above, the time usage of the catheter is tracked and stored on the handle board itself, preventing the time usage from being changed or reset. When the catheter has been used for the entire time usage limit, the catheter may become non-functional.

[0206]

[0270] In one embodiment, the controller / generator may be configured to communicate with the catheter periodically, at set or random time intervals. When the generator communicates with the catheter, it may check these imprinting limits, including time use limits or treatment cycle limits, to ensure the catheter is still valid. If communication is not possible between the catheter and the generator, the system may become idle / inoperable until communication with the catheter is re-established.

[0207]

[0271] In another embodiment, a system is disclosed that allows for field upgrades to allow for easy upgrades of the controller / generator firmware. A bootloader resides persistently in the controller / generator memory. When the controller is powered on, the bootloader always runs first and is responsible for:

[0208]

[0272] 1) When removable memory (e.g., an SD card) is inserted into a control unit and the memory contains a valid application code image, under certain circumstances this image may be burned into the control unit's code memory. Whether the code image is burned depends on a key file that must be present on the removable memory. The key file specifies the version of the code image intended to be burned. The image will only be burned if (a) the version number specified in the key is the same as the version number embedded in the code image, (b) the version of the code currently loaded on the control unit is less than the version of the code image (or no code is loaded on the control unit at all), and (c) the code image passes a code integrity check (a checksum is embedded in the code image). Function (b) prevents the user from downgrading the code or accidentally burning the same version multiple times if the SD card remains in the socket.

[0209]

[0273] 2) If a code image exists in the controller's code memory (or it has just been burned), the boot loader can verify its integrity, and if the code image is valid, the boot loader will transfer control to it and begin executing the controller application. The application code image may contain an embedded branch table that allows for proper interrupt handling.

[0210]

[0274] FIGS. 39A-39C illustrate one embodiment of treatment of perforator veins. As shown in FIG. 39A, the perforator veins pass through the fascial layer F to connect the deep venous system DV with the superficial venous system SV, as generally shown. With reference to FIG. 39A, a target treatment site below the fascial layer may be accessed from within the PV under ultrasonic guidance by an ultrasound probe 3902. In this embodiment, although not required, an introducer 3904 including a needle or cutting tip (e.g., a scalpel) may make a skin incision to access the PV through the skin above the fascial layer in the superficial tissue compartment. With reference next to FIG. 39B, an angiocatheter 3906 may be introduced into the PV through the skin incision. It should be understood that in some embodiments, the skin incision step described in FIG. 39A is not performed. Instead, an angiocatheter including a needle or cutting tip may be used directly to puncture the skin and access the PV. In one embodiment, the PV is accessed above the fascia by an angiocatheter. In another embodiment, the PV is accessed below the fascia with an angiocatheter. In yet another embodiment, the PV is accessed above the fascia with an angiocatheter, but then advanced further within the vein to a position below the fascia. Final access is ensured using ultrasound guidance and by noting blood "flashback" from the angiocatheter. Once the PV is accessed, the inner needle can be removed, exiting the introducer tube within the PV, ready to accept the introduction of a flexible device (such as a flexible catheter with one or more heating element segments described herein).

[0211]

[0275] Referring to FIG. 39C , a flexible device (such as a flexible catheter having one or more heating element segments described herein) can be inserted into a vascular catheter to access a PV. As described above, in some embodiments, the vascular catheter is positioned within the PV above the fascia, or sometimes it is positioned below the fascia. If above the fascia, the catheter can be advanced intravenously past the fascial layer to access portions of the PV below the fascial layer. The flexible catheter can be advanced within the target PV to position one or more heating elements within the PV and below the facial layer (F) at an initial treatment site. As described above, the catheter can be configured to apply thermal therapy to the target vein with a single press of a button on the catheter handle or through the use of a remote footswitch. For example, in one embodiment, pressing a button on the catheter handle delivers a 20-second treatment to the target site at a non-adjustable setpoint temperature of 130°C. The catheter can then be manipulated within the PV to treat additional segments or areas within the PV if needed.

[0212]

[0276] In some embodiments, treatment of the PV can be provided from outside the PV. In these embodiments, a target venous treatment site below the fascial layer is accessed under ultrasound guidance starting below the fascial layer. The PV is treated as described above by applying heat to the PV using a flexible catheter for a specified time period and temperature (e.g., 20 seconds of treatment at 130°C). In yet another possible variant, for example, treatment of a portion of the PV can be performed by placing a heating coil within a selected PV segment or outside or adjacent to a selected PV segment.

[0213]

[0277] More specifically, an introducer with a removable needle tip may be introduced through the skin, directed toward the target treatment site and the perforator vein (PV). Next, under ultrasound guidance, the needle and introducer may be advanced toward and enter the PV below the fascial layer within the deep tissue compartment. The needle may then be withdrawn. At this point, access to the interior of the perforator vein (PV) through an opening in the vessel wall is provided. Next, a treatment catheter may be advanced along the introducer to the PV treatment site below the fascial layer. Once the treatment segment (e.g., the heated length of the catheter) is satisfied that it is adjacent to or at the desired location within the PV, the user may activate thermal therapy (e.g., by pressing a button on the handle of the flexible catheter). Pressing the button initiates an energy delivery protocol within the generator to deliver energy to a single coil segment at a predetermined temperature for a predetermined period of time (e.g., 20 seconds at a 130°C setpoint).

[0214]

[0278] Once treatment is complete, the heating catheter and cannula may be removed, leaving a contracted region within the perforator vein. Optionally, the catheter may be maneuvered to position the treatment segment at one or more other treatment sites before being withdrawn. Additionally, although not shown, the catheter may be advanced to the treatment site over a previously placed guidewire. Additionally, although not shown, prior to delivering energy to the treatment site, a local tumescent fluid / anesthesia (i.e., saline + lidocaine, with or without an epinephrine mixture) may be administered outside the PV to protect the surrounding tissue and minimize any pain during treatment.

[0215]

[0279] Figure 40A is a graph of the temperature measured over a 20 second treatment period delivered by the catheter in Figure 36A, as measured by a thermocouple positioned as shown in Figure 36B. The graph shows that the 130°C set point was measured by a thermocouple in the heating coil from immediately after the start ramp or about 5 seconds until the end of the 20 second treatment session.

[0216]

[0280] FIG. 40B is a graph of the external temperature near the treatment coil of the catheter of FIG. 36A measured at points adjacent the distal, central, and proximal portions of the heating coil during the 20-second treatment period of FIG. 39A. The graph shows the temperature increase as power is delivered to the treatment segments. A relatively stable and expected temperature increase is observed in all measurement segments during the majority of the 5- to 20-second treatment session. These graphs show that the maximum temperature measurement in the external tissue adjacent to the treatment area did not exceed approximately 95°C until power delivery was terminated at the end of the 20-second treatment session. This delta offset between the catheter's external temperature and its internal measured setpoint temperature can be optimized and / or adjusted during the design process by material selection, material dimensions, and the setpoint temperature itself.

[0217]

[0281] In various embodiments, the generators described herein include hardware and software modifications to recognize and interact with any number of alternative embodiments of the single thermal treatment segment. Additionally, numerous different PID tunings, desired power curve shapes, power delivery curve shapes, or other controllable generator outputs are possible utilizing the concepts described herein for optimal use of the single heated segment catheter. Still further, the generator includes operational instructions such that, when a button is actuated on the handle, the temperature profile of FIGS. 40A-40B or a functional equivalent is produced within the target region of the vasculature. Additionally or optionally, the generator display may indicate that a single segment catheter is connected and may include additional functionality via interaction with the display, or may not provide functionality for display interaction.

[0218]

[0282] FIG. 41 is a method 400 for selecting a single segment thermal therapy TRS catheter or a multiple selectable thermal segment therapy TRS catheter to deliver therapy to a treatment site within a patient's venous vasculature.

[0219]

[0283] First, in step 405, a patient is evaluated for thermal treatment to a portion of the venous vasculature, which involves the selection of an appropriate heating catheter device.

[0284] Next, there is a decision to proceed with a single heating element catheter (step 410) or a multiple selectable heating segment catheter (step 415).

[0220]

[0285] The selected catheter type is connected to the generator by inserting the catheter TRS connector into the appropriate socket on the front of the generator 104 (step 420).

[0221]

[0286] In step 425, the generating device automatically recognizes the catheter type as single or multiple segments, then (i) enables operation of the handle push button or foot switch, (ii) changes the display to indicate the catheter type, and (iii) enables display functions (if any).

[0222]

[0287] Using an appropriate vascular access technique (e.g., FIG. 39A), a heating catheter is advanced to the target anatomical structure using ultrasound guidance (step 430).

[0288] If the answer to step 440 is YES and a single heating segment is being used to treat a perforator vein, the heating element is advanced across the fascia to the initial treatment site (step 445).

[0223]

[0289] When in the desired position, the user presses a push button or foot switch on the handle and the generator delivers the desired power profile (step 450).

[0290] If the user wishes to treat another segment, the answer to step 455 is YES, and the user adjusts the catheter position and repeats steps 450 and 455 until the answer to step 455 is NO, at which point the user proceeds to step 460 and removes the treatment catheter, concluding the procedure.

[0224]

[0291] Returning to step 430, if the answer to step 465 is YES and a multiple selectable heating segment catheter is being used to treat the vein, a heating element segment is advanced within or adjacent to the initial venous treatment site (step 470).

[0225]

[0292] When in the desired position, the user interacts with the generator to indicate the number of segments to be activated, after which the user presses a button on the handle and the generator delivers the desired power profile (step 475).

[0226]

[0293] If the user wishes to treat another segment, the answer to step 455 is YES, and the user adjusts the catheter position, interacts with the generator display, and repeats steps 470 and 475 until the answer to step 455 is NO, at which point the user proceeds to step 460 and removes the treatment catheter, concluding the procedure.

[0227]

[0294] In additional alternative embodiments, the treatment catheter and energy delivery generator may be adapted for blind connectors (i.e., self-aligning connectors) or other push-to-connect type connectors to establish communication therebetween. This type of connection mode contrasts with conventional multi-pin connectors common to catheter and generator interfaces, which use several separate pin-and-socket connection points that must be fully engaged and in a specific orientation to establish catheter-generator communication.

[0228]

[0295] In contrast, consider Figures 42A-42D, which illustrate several different "TRS-style" connectors, including TS, TRS, TRRS, and TRRRS designs. Figure 42A is a side view of a tip-sleeve or TS connector. Figure 42B is a side view of a tip-ring-sleeve or TRS-style connector. Figure 42C is a side view of a tip-ring-ring-sleeve or TRRS-style connector. Figure 42D is a side view of a tip-ring-ring-ring-sleeve or TRRRS-style connector. Any modification, or modifications, to these simple push-to-connect style connectors may be used in the catheter / generating devices described herein.

[0229]

[0296] When a TRS-type connector is implemented in the catheter described herein, the catheter may further include an interconnecting cable extending between the catheter handle and the TRS-type connector on the end of the cable. In this embodiment, the TRS connector is configured to be received in a socket of an energy delivery controller or generator. The interconnecting cable may include power delivery lines, communication lines, and a shared ground line that provides a return for the power delivery lines and communication lines to the energy delivery controller. In this embodiment, the lines of the interconnecting cable may be configured to terminate in the TRS-type connector.

[0230]

[0297] The flexible nature of the catheters provided herein offers many advantages over other competing devices in the field. First, the flexible catheters and the long lengths of the provided catheters (e.g., up to 40 cm to 100 cm in length) allow for deeper access within the PV. In some embodiments, the flexible catheters can be inserted into the PV several centimeters below the fascial layer. The ability to access the PV far below the fascial layer provides the opportunity to apply multiple treatments below the fascial layer. For example, a flexible catheter with a 0.5 cm heating element length can be inserted into the PV below the fascial layer, and the heating element can be activated to provide a first treatment below the fascial layer. The catheter can then be moved (i.e., retracted), and the heating element can be activated to provide a second treatment below the fascial layer. This process can be repeated until the catheter is positioned above the fascial layer. Treatment can continue within the PV even above the fascial layer until the desired treatment is completed. Thus, in some embodiments, one or more treatments are provided within the PV below the fascial layer and one or more treatments are provided above the fascial layer.

[0231]

[0298] 43 is a flowchart describing one embodiment for treating a patient's perforator veins. In step 4402, a flexible catheter may be inserted into a target region of the perforator vein at or below the fascial layer. In step 4404, a heating element of the catheter may be activated to provide heat therapy or thermal treatment to the target region at or below the fascial layer. Next, in optional step 4406, the flexible catheter may be moved to a second target region within the PV (e.g., withdrawn proximally toward the patient's skin), but still at or below the fascial layer. In optional step 4408, another thermal treatment may be applied at the second target region. Optional steps 4406 and 4408 may be repeated for subsequent third, fourth, fifth, sixth, etc. target regions at or below the fascial layer, if desired.

[0232]

[0299] In step 4410, the flexible catheter may now be moved (e.g., retracted) to a third target region of the PV above the fascial layer. Finally, in step 4412, the heating element may be activated to provide thermal therapy to the third target region above the fascial layer.

[0233]

[0300] In some embodiments, two or more treatment cycles may be performed at the same location within the vein before moving on to the next treatment site. For example, referring to the flowchart of FIG. 43, the majority of the treatment cycle, or alternatively, the longest treatment time, may be applied to the first target area. As treatment progresses to the second, third, fourth, etc. target areas, fewer or equal treatment cycles or treatment times may be applied to each subsequent target area. For example, in one embodiment, 40 seconds of total treatment time may be applied to the first target area, and 20 seconds of total treatment time may be applied to each subsequent target area (e.g., the second, third, fourth, etc. target area). In another embodiment, 80 seconds of therapy may be applied to the first target area, 60 seconds of therapy may be applied to the second target area, 40 seconds of therapy may be applied to the third target area, and 20 seconds of therapy may be applied to the fourth target area.

[0234]

[0301] 44 is another flowchart illustrating a method for treatment planning for treatment of a patient's veins, such as a perforator vein. As described above, a flexible catheter having a heating element as described herein may be inserted into the patient's perforator vein. In some embodiments, the perforator vein is accessed at a location positioned above the patient's fascial plane. The catheter may then be advanced within the vein from the access location, past the fascial plane, to a first treatment location within the perforator vein and below the fascial plane.

[0235]

[0302] The location of the heating element of the catheter relative to the patient's anatomy can be used to determine the type of treatment for the patient. For example, if the entire length of the heating element (or heating coil) is below the deep fascial plane (step 402) and multiple segments or treatments are planned (step 404), at least six treatments per segment can be planned or delivered below the deep fascial plane and no more than six treatments per segment can be planned or delivered above the deep fascial plane in step 406.

[0236]

[0303] For purposes of this embodiment, a "segment" may be defined as a location within a perforator vein where treatment is planned, and a "treatment" may be defined as the application of thermal energy by a heating element on a catheter for a predetermined time (e.g., 20 seconds) and at a predetermined temperature (e.g., 130°C).

[0237]

[0304] Thus, in one embodiment, a treatment regimen including steps 402, 404, and 406 may include at least six 20-second treatments at 130° C. in the perforator veins below the deep fascial plane, and no more than six 20-second treatments at 130° C. in the perforator veins above the deep fascial plane. It should be understood that the predetermined time and predetermined temperature may be adjusted.

[0238]

[0305] If the entire length of the heating element (or heating coil) is below the deep fascial plane (step 402), and if multiple segments or treatments are not planned (step 404), then approximately 10-12 treatments may be planned or delivered at the treatment site below the deep fascial plane in step 408.

[0239]

[0306] Similarly, if the entire length of the heating element (or heating coil) is not below the deep fascial plane (step 402), and if multiple segments or treatments are not planned (step 410), then in step 408, approximately 10-12 treatments may be planned or delivered at treatment sites either above the deep fascial plane or both above and below the deep fascial plane.

[0240]

[0307] Finally, if the entire length of the heating element (or heating coil) is not below the deep fascial plane (step 402), and if multiple segments or treatments are planned (step 410), then in step 412, approximately 8-12 treatments may be planned or delivered in each segment either above the deep fascial plane or both above and below the deep fascial plane.

[0241]

[0308] The number of treatments / segments selected should take into account the vein size, the length of the vein to be treated, the anatomy of the tributaries within the segment being treated, bubbling changes in the heating element during treatment (as observed under ultrasound), and echogenicity changes / shadowing during and after treatment under ultrasound. The number of treatments described in FIG. 44 is not required but may instead be used as guidance for selecting how many treatments should be performed in each segment of the vein to successfully occlude the vein. In addition to these guidelines, ultrasound visualization feedback may also be used to determine the success of each treatment and manage the number of treatment cycles to perform in each segment. Successful occlusion often manifests as a slowing of bubbles / bubbles seen in the treated vein under direct ultrasound visualization (e.g., with each successive vein segment treated, the intraluminal bubbling effect often decreases as the vein is ablated and any further blood flow is blocked), and with each additional segment being successfully treated, the ultrasound echo density / echogenicity of the tissue also becomes greater, causing a far-field ultrasound shadowing effect that may often indicate successful vein / tissue ablation. Finally, the echogenicity of the catheter's heating coil can also be used to visualize its location within the vein with each successive pullback to ensure consistent and complete vein ablation along the multi-segment treatment length.

[0242]

[0309] These and other examples provided herein are intended to illustrate, and not necessarily to limit, the implementations described. As used herein, the term "implementation" means an implementation that serves to illustrate by way of example, not limitation. The techniques described in the foregoing text and figures can be mixed and matched as appropriate to produce alternative implementations.

[0243]

[0310] As used herein, the term "embodiments" means embodiments that serve to illustrate by way of example and not limitation. The techniques described in the foregoing text and figures can be mixed and matched as appropriate to produce alternative embodiments.

Claims

1. a heating catheter including a bulging rounded tip, a handle having a push button, a heating element formed from a resistance coil positioned at a distal end of the heating catheter, and a catheter shell extending along the outside of the heating element and terminating in abutment against a proximal curved portion of the bulging rounded tip, wherein the distal end of the heating element is retracted from the distal-most end of the heating catheter only by the bulging rounded tip; an energy delivery control device having a display and a socket for receiving a TRS-type connector and configured to communicate with the push button on the handle; a thermocouple in the resistive coil and in electrical contact with the TRS-type connector, the thermocouple being galvanically isolated from a reference earth using an isolation amplifier powered by a voltage source that is galvanically isolated from the circuit for powering the handle; an interconnection cable extending between the handle of the heating catheter and a TRS-type connector at a terminal end of the interconnection cable, the TRS-type connector configured to be received in the socket of the energy delivery control device, the interconnection cable comprising: a power transmission line; A communication line, and a shared ground wire providing a return path for the power delivery wires and the communication wires to the energy delivery control device, the power delivery wires and the communication wires terminating in the TRS type connector, the heating catheter having information in a flash memory to identify the type of heating catheter, the information including a region code that limits use of a particular catheter type to a particular geographic region, and including one or more treatment cycle use restrictions.

2. 10. The system of claim 1, wherein the TRS-style connector is in a tip-ring-sleeve, tip-ring-ring-sleeve, tip-ring-ring-ring-sleeve, or blind-connect configuration.

3. The system of any one of claims 1 to 2, wherein the heating element comprises a generally helical shaped resistive heater coil disposed at the distal end of a shaft.

4. The system of any one of claims 1 to 3, further comprising an insulating coating covering the heating element.

5. The system of any one of claims 1 to 4, wherein the heating catheter is flexible or has a rigid section and a flexible section.

6. The system of any one of claims 1 to 5, wherein the heating catheter has an insertable length of 40 cm.

7. 7. The system of any one of claims 1 to 6, further comprising a footswitch in communication with the energy delivery controller, wherein initiation of delivery of therapy to a treatment site on a patient is initiated by user interaction with the energy delivery controller using a push button on the handle or the footswitch.

8. The system of claim 1 , wherein the heating catheter further comprises a circuit board having firmware imprinted with the catheter type during manufacture.

9. 9. The system of claim 8, wherein the heating catheter is rendered inoperable by the energy delivery controller if the energy delivery controller does not recognize or accept the type of catheter imprinted on it.

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