A microwave ablation catheter

Abstract

The present invention provides a microwave ablation catheter designed for renal nerve ablation, incorporating an advanced cooling system to optimize performance. The catheter features a body with distal and proximal portions, housing a microwave antenna within the distal portion. This antenna, in electrical communication with a microwave generator, delivers microwave energy for tissue ablation. There is a cooling system comprising an external coolant pump that directs cooling fluid from a first internal lumen to a second internal lumen. The fluid contacts the microwave antenna before entering the second lumen. A first thermocouple within the second lumen monitors temperature and communicates with the coolant pump to dynamically adjust the flow rate of the cooling fluid based on sensed temperature thresholds.

Description

A MICROWAVE ABLATION CATHETERTECHNICAL FIELD

[0001] The present invention generally relates to catheter ablation devices used in renal denervation procedures. Specifically, the present invention relates a microwave ablation catheter for ablating renal nerves in a subject, featuring a cooling mechanism within the catheter itself that utilises irrigation fluid to optimize cooling during the ablation process.BACKGROUND

[0002] The following references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the following prior arts discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of the present invention of which the identification of pertinent prior art proposals is but one part.

[0003] Denervation means loss of nerve supply. The primary causes of denervation include disease, chemical toxicity, physical injury, or intentional surgical interruption of a nerve. One example of a denervation procedure that has been found to produce beneficial effects is renal denervation.

[0004] Renal denervation is a minimally invasive procedure used to treat resistant hypertension, which is termed as high blood pressure that doesn’t respond very well to medications. This procedure targets the sympathetic nerves located in the renal arteries, which play a crucial role in regulating blood pressure. By disrupting these nerves, renal denervation aims to lower blood pressure levels effectively.

[0005] Currently, renal denervation procedures are performed using ablation catheters. These catheters are inserted into the renal arteries, which supply blood to the kidneys. In these catheters radiofrequency energy or ultrasound energy is utilized to heat and disrupt the nerves surrounding the arteries. This intervention effectively reduces nerve signals responsible for enhancing blood pressure.

[0006] The catheter is typically navigated to the desired location within the artery or veins under imaging guidance, such as fluoroscopy or ultrasound.

[0007] There exist two types of ablation catheters namely radiofrequency (RF) energy and ultrasound catheters to achieve renal denervation.

[0008] RF energy catheters generate heat that is applied to the vessel wall surrounding the renal arteries. This heat thermally damages the sympathetic nerves, thereby reducing their ability to transmit signals that contribute to elevated blood pressure. For example, Medtronic Symplicity Spyral Catheters use radiofrequency ablation, wherein the frequency is in the range of 350 to 500 kHz.

[0009] On the other hand, ultrasound-based catheters, utilize high-frequency sound waves to achieve a similar effect. These sound waves generate mechanical vibrations that create localized tissue damage around the renal arteries, leading to a reduction in nerve activity and subsequent blood pressure control. For example, Recor Medical Paradise catheter uses ultrasound energy, wherein the frequency is the range of 1 to 2 MHz.

[0010] These conventional catheters use much lower frequencies compared to microwave energy which typically uses frequencies in the range of 300 MHz to 300 GHz.

[0011] US 11039884 B2 relates to a microwave ablation device comprises a feed line, a microwave radiator and a device outer sheath in which at least part of the feed line is contained. The sheath in use, allows an irrigation liquid to flow therethrough, wherein the feed line has a junction with the radiator has an outer conducting shield terminating and insulated at the junction. The feed line has a conductive core that extends to the radiator. The conductive core forms a radiating element electrically insulated from its surrounding environment. The radiator is unbalanced.

[0012] AU 2019321870 Al relates to a catheter ablation device for delivery of energy (such as microwave energy) via a radiating antenna to a selected region of tissue, the device having an elongated catheter with an outer sheath, configured to allow flow offluid along the catheter to exit through one or more orifices adjacent to the antenna. The device includes an impedance monitoring system having two electrodes arranged respectively inside and outside said catheter sheath, the impedance monitoring system including an electric circuit incorporating an ionic conductivity path through said fluid. The device is introduced into a blood vessel and the invention allows monitoring of changes in the size of the blood vessel during an ablation procedure, as it can be used to measure the impedance of an electrical circuit including a blood path in the blood vessel in the region of the ablation, the measured impedance providing a measure of vascular calibre.

[0013] Existing microwave, radiofrequency (RF), and ultrasound ablation catheters face several significant drawbacks

[0014] Firstly, many of these catheters rely on external irrigation systems for cooling, which can limit their reach and maneuverability during procedures. This external setup increases procedural complexity and may hinder precise catheter placement.

[0015] Secondly, there is variability in the effectiveness of microwave, RF, and ultrasound ablation catheters in achieving long-term treatment outcomes for conditions such as hypertension and tumor ablation.

[0016] Moreover, these catheters carry inherent risks of complications, including vascular injury and the potential for renal artery stenosis. The problem with these catheters lies in their design as they rigid probes with ceramic tips and a thicker diameter, which makes them inflexible. This lack of flexibility can lead to difficulties during insertion and maneuvering within the body, increasing the risk of causing unintended damage or puncturing soft tissue. Additionally, the thick diameter of the catheters having size ranging between at 8-10 French, preferably 8 French may not be suitable for all patients or procedures, potentially leading to further complications.

[0017] Lastly, achieving complete nerve ablation, particularly in targeted areas like renal nerves for hypertension treatment, remains a challenge. Incomplete nerve ablation can compromise treatment efficacy and necessitate additional procedures.

[0018] In light of the above drawbacks, there is a need for an alternative type of ablation device namely an internally cooled microwave catheter that can overcome the length limitations faced by existing technologies without sacrificing cooling performance.

[0019] The catheter device integrates precise and uninterrupted cooling to enhance procedural safety and reliability.

[0020] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.SUMMARY

[0021] PROBLEMS TO BE SOLVED

[0022] It may be an advantage to provide an internally cooled microwave catheter that overcomes the short length limitations of existing technologies.

[0023] It may be an advantage to provide a microwave ablation catheter that has a length of about 900 mm without compromising cooling performance, facilitating greater reach, particularly for complex ablations in the kidneys and heart.

[0024] It may be an advantage to provide a microwave ablation catheter that eliminates the need for external irrigation fluid removal thereby enhancing manoeuvrability and simplifying procedures.

[0025] It may be an advantage to provide a microwave ablation catheter that may be used for renal denervation or cardiac ablation procedures.

[0026] It may be an advantage to provide microwave ablation catheter that may be used for cardiac ablation when large deep lesions are required.

[0027] It may be an advantage to provide a microwave ablation catheter with an internal cooling mechanism that avoids biocompatibility issues associated with external irrigation materials, thereby minimizing subject risks and precisely controlling the flow rate.

[0028] It may be an advantage to provide a microwave ablation catheter that ensures consistent and unobstructed flow of cooling liquid throughout the procedure.

[0029] It may be an advantage to provide a microwave ablation catheter having a lumen for housing guidewires or mechanisms, providing the advantage of precise navigation and manipulation of the catheter tip within the body.

[0030] It may be an advantage to provide a microwave ablation catheter that consists of deflectable catheter sheaths, a feature not present in any currently available internally cooled microwave ablation catheters.

[0031] It may be an advantage to provide a lubricious coating to the catheter’s bloodcontacting surface for reducing thrombus formation.

[0032] It may be an advantage to provide a microwave ablation catheter that leverages advanced low friction polymer compound and additives in the extrusion process to achieve a lubricious property in the catheter sheath material without compromising joint strength.

[0033] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0034] MEANS FOR SOLVING THE PROBLEM

[0035] The present invention may be envisioned to a microwave ablation catheter for ablating renal nerves in a subject, facilitated by a cooling mechanism that utilizes irrigation fluid to optimize cooling during the ablation process.

[0036] In a first aspect of the present invention, the catheter may be adapted for delivering microwave energy in ablating tissue, the catheter comprising a catheter body having a distal and proximal end; a microwave antenna situated or positioned between a first internal lumen and a second internal lumen, and located within the distal portion of the catheter body, the microwave antenna is in electrical communication with a microwave generator to deliver microwave energy to the antenna; an antenna cooling system comprising an external coolant pump for directing cooling fluid from the first internal lumen to the second internal lumen, wherein the cooling fluid from the first internal lumen contacts the microwave antenna prior to entering the second internal lumen; a first thermocouple positioned in the second internal lumen and in communication with the external cooling pump and the external cooling pump is configurated to dynamically adjust the flow rate of the cooling fluid to the microwave antenna when predetermined temperature thresholds are sensed by the thermocouple.

[0037] Preferably, the flow rate of the cooling fluid is between 30 ml / min- lOOml / min.

[0038] Preferably, the first internal lumen is an internal in-flow lumen and the second internal lumen is an internal out-flow lumen.

[0039] Preferably, the catheter includes at least one electrode located on the outer periphery of the catheter, wherein the electrode is configured to perform at least one function from the group of: sensing, pacing, mapping, and ablation.

[0040] Preferably, the catheter further comprises a second thermocouple positioned at the electrode located on the outer periphery of the catheter.

[0041] Preferably, the first thermocouple is configured to monitor the cooling efficiency of the microwave antenna.

[0042] Preferably, the second thermocouple is configured to measure the temperature of the blood or tissue.

[0043] Preferably, the catheter further comprises a guide wire lumen extending from the proximal end to the distal end, wherein the guide wire lumen allows for a guide wire to extend therethrough.

[0044] Preferably, the microwave antenna is compatible with standard coaxial cables having a diameter of about 1.13 mm with an impedance value of approximately 50 Ohms.

[0045] Preferably, the antenna cooling system is in fluid communication to a proximal end of the first internal lumen.

[0046] Preferably, the catheter comprises a lubricious coating to the outer surface of the catheter.

[0047] Preferably, the microwave ablation catheter operates at a frequency ranging between 300 MHz to 300 GHz. More preferably, the microwave ablation catheter operates at a frequency between 2 GHz to 3 GHz, the preferred frequency being 2.45 GHz.

[0048] Preferably, the microwave antenna may be selected from the group consisting of monopole, dipole, slotted, or quarter-wavelength antenna.

[0049] Preferably, the catheter body further comprises: a first elongate tubular member having a proximal end portion and distal end portion, and houses a second elongate tubular member and contains plurality of lumens; the second tubular member includes a proximal end portion and a distal end portion extending from the distal end of the first tubular member; a catheter shaft extending from the proximal end to the distal end of the catheter; and a knob-like control mechanism attached to the proximal end of the first tubular member, wherein the knob-like control mechanism is configured to control the movement, deflection, or positioning of the catheter within the body of the subject.

[0050] Preferably, the at least one lumen is positioned within the first elongate member from the proximal end to the distal end

[0051] Preferably, the at least one lumen is positioned within the second elongate member from the proximal end to the distal end

[0052] Preferably, the catheter further comprises a catheter sheath that surrounds and protects the catheter shaft.

[0053] Preferably, the catheter further comprises: a handle, wherein the handle includes aa proximal end and a distal end and the catheter device extending from the distal end of the handle; an operating mechanism for effecting relative displacement between the first elongate tubular member and the second elongate tubular member of the catheter.

[0054] Preferably, the operating mechanism is a knob that is axially slidable on the handle of the catheter body.

[0055] Preferably, the catheter has a length of about 900mm.

[0056] Preferably, the catheter may or may not be deflectable.

[0057] Preferably, a guide wire lumen is not required if the catheter is deflectable.

[0058] Preferably, the guide wire lumen can also be used for injecting contrast, especially when the catheter is not deflectable.

[0059] Preferably, the distal end of the first tubular member and the distal end of the second tubular member are joined through a process of plastic welding.

[0060] Preferably, the material of the first tubular member and the second tubular member is Polyether block amide (PEBAX).

[0061] Preferably, the tip of the catheter may bend bidirectionally at an angle ranging between 0 to ±90 degrees for an effective ablation procedure.

[0062] Preferably, the catheter includes a tapered tip structure that extends beyond the microwave antenna to accommodate a guide wire extending through a guide wire lumen or the fluid passage in the catheter body.

[0063] Preferably, the proximal end of the catheter body may be equipped with at least six connectors for various components, including the guide wire, microwave generator, coolant inflow, coolant outflow, sensing and pacing EP system and saline pressure infuser bag.

[0064] Preferably, the connectors from the proximal end of the catheter may be integrated to be a single connector to achieve better usability.

[0065] The invention is to be interpreted with reference to the at least one of the technical problems described or affiliated with the background art of the invention. The present aims to solve or ameliorate at least one of the technical problems and this may result in one or more advantageous effects as defined by this specification and described in detail.BRIEF DESCRIPTION OF THE FIGURES

[0066] The disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various implementations of the disclosure. The drawings, however, should not be taken to limit the disclosure to the specific implementations, but are for explanation and understanding only.Figure 1A illustrates a cross-sectional view illustrating a first design of the lumen, creating a symmetrical configuration;Figure IB illustrates a cross-sectional view illustrating a second design of the lumen, creating a symmetrical configuration;Figure 1C illustrates a cross-sectional view illustrating a third design of the lumen, creating a symmetrical configuration;Figure ID illustrates a cross-sectional view illustrating a fourth design of the lumen, creating a symmetrical configuration;Figure IE illustrates a cross-sectional view illustrating a fifth design of the lumen, creating a symmetrical configuration;Figure 2 illustrates a cross-sectional view of the symmetrical lumen arrangement, showing a pull wire attached to two of the symmetrical lumens to achieve catheter deflection;Figure 3 illustrates a schematic view of the catheter bending due to pull wire manipulation;Figure 4 illustrates a cross-sectional view of catheter coolant movement;Figure 5 illustrates another cross-sectional view of the distal end of the catheter highlighting the components;Figure 6 illustrates an ablation catheter, in accordance with an embodiment of the present specification;Figure 7 represents the microwave catheter system fully assembled and ready for use, including all necessary equipment and connections for the procedure;Figure 8 illustrates a side sectional view of the distal tip of a catheter, in accordance with an embodiment of the present specification;Figure 9 illustrates a side sectional view of the distal tip of a catheter with guidewires, in accordance with an embodiment of the present specification;Figure 10 illustrates a sectional view of the thermocouple placed inside the return irrigation lumen;Figure 11 illustrates a sectional view depicting the placement of an additional thermocouple close to the distal electrode;Figure 12A illustrates a cross-sectional view of the distal end of the catheter with coolant channels and microwave antenna;Figure 12B depicts a sectional view of the coolant inflow and outflow in the separate lumens within the multi-lumen catheter tube;Figure 13A illustrates a cross-sectional view of the distal end of the catheter highlighting the positioning of the microwave antenna with adjacent lumens;Figure 13B depicts a sectional view of the sensing wire and guide wire passing through separate individual lumens within the multi-lumen catheter tube;Figure 14A illustrates a cross-sectional view of the distal end of the catheter highlighting the braided catheter shaft;Figure 14B depicts a sectional view of the multi-lumen catheter tube joint with braided catheter shaft tube;Figure 15A illustrates a cross-sectional view of the distal end of the catheter highlighting the ring electrode;Figure 15B depicts a sectional view of the ring electrode with sensing wire passing through the inside of one of the individual lumens of the catheter shaft;Figure 16 illustrates a schematic view of proximal end of the multi-lumen tube;Figure 17 illustrates a schematic view of the muti-lumen tube being assembled with lumen and over-moulded plastic; andFigure 18 illustrates a cross-sectional view of the distal end of the catheter highlighting the positioning of the pressure sensor;Figure 19 illustrates a sectional view of a control system arrangement for a micro wave ablation catheter;Figure 20 illustrates a system diagram showing the arrangement of control components in a microwave ablation system; andFigure 21 illustrates a system diagram an extension of Figure 20 illustrating the arrangement of control components.DESCRIPTION OF THE INVENTION

[0067] Preferred embodiments of the invention will now be described with reference to the accompanying drawings and non-limiting examples, [insert embodiment discussion]

[0068] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms, in keeping with the broad principles and the spirit of the invention described herein.

[0069] The present invention and the described preferred embodiments specifically include at least one feature that is industrial applicable.

[0070] The term “subject” includes animals, preferably mammals, including humans. In some embodiments, the subject is a primate. In other preferred embodiments, the subject is a human.

[0071] The terms “returned irrigation lumen” and “internal out-flow lumen” convey the same meaning in the context of the present invention.

[0072] As used herein, the term "distal" refers to the portion that is being described which is further from a user, while the term "proximal" refers to the portion that is being described which is closer to a user.

[0073] The term “sensing” in the context of renal denervation involves the use of specialized electrodes or sensors to monitor and measure electrical activity in the renal nerves.

[0074] The term “pacing” in the context of renal denervation involves applying controlled electrical impulses to the renal nerves.

[0075] The term “plastic welding” in the context of the present invention is a process of joining two or more pieces of plastics together using heat, pressure, and sometimes filler materials.

[0076] In the context of the present invention, the words “comprise”, “comprising” and the like are to be construed in their inclusive, as opposed to their exclusive, sense, that is in the sense of “including, but not limited to”.

[0077] The term “reflowed over-molded plastic” in the context of the present invention refers to a manufacturing process where plastic is molded over another material or and then the assembly is heated (reflowed) to enhance bonding and structural integrity.

[0078] The invention is directed, in part, to a microwave ablation catheter for ablating renal nerves in a subject, facilitated by a cooling mechanism that utilizes irrigation fluid to optimize cooling during the ablation process.

[0079] The catheter operates using frequencies ranging from 300 MHz to 300 GHz, preferably between 2 GHz to 3 GHz.

[0080] The microwave ablation catheter operates at a frequency of 2.45 GHz

[0081] The catheter has a length of about 900mm. It may be appreciated that the length of the catheter may be more than 900mm.

[0082] Referring to Figure 1 that illustrates five different designs 38, 39, 40, 41, 42 of the lumen.

[0083] Figure 1A illustrates a cross-sectional view of a first lumen design 38 with one large lumen at the top center 38 A, two small circular lumens 38B, 38C at the bottom and one large U-shaped lumen 38D surrounding the bottom and side lumens creating a symmetrical configuration. The design is symmetrical along a central axis, ensuring even distribution of forces and consistent bending characteristics.

[0084] Figure IB illustrates a cross-sectional view of a second lumen design 39 featuring one large circular lumen 39A at the top centre , two smaller circular lumens 39B, 39C at the bottom and a U-shaped lumen 39D surrounding the two smaller circular lumens, creating a symmetrical configuration.

[0085] Figure 1C illustrates a cross-sectional view of a third lumen design 40, featuring one large circular lumen at the center 40A, two smaller circular lumens 40B, 40C on either side of the central lumen 40A, two large U-shaped lumens 40D and 40E surrounding the large circular lumen 40A and the two small lumens 40B, 40C creating a symmetrical configuration.

[0086] Figure ID illustrates a cross-sectional view of a fourth lumen design 41, showing one large circular lumen 41 A at the top centre, two smaller circular lumens 4 IB, 41 C at the bottom and a U-shaped lumen 41D surrounding the two smaller circular lumens, creating a symmetrical configuration.

[0087] Figure IE illustrates a cross-sectional view of a fifth lumen design 42 featuring one large circular lumen 42A at the top center, two smaller circular lumens 42B, 42C and two small oval shaped lumens 42D, 42E at the bottom of the large lumen 42A and a U- shaped lumen 42F surrounding the four small lumens, creating a symmetrical configuration.

[0088] Furthermore, referring to Figure 2 that illustrates the cross section of the multi lumen tube 26 in the catheter body 2 with four distinct lumens 26A, 26B, 26C, 26D focusing on the internal arrangement of the lumen. The arrows in Figure 2 indicate the direction in which the pull wires can move within the catheter body 2.

[0089] Referring to Figure 3 that depicts the catheter 1 bending mechanism 43 due to pull wire manipulation. Tensioning the pull wires causes the catheter 1 to bend in a controlled manner, with the arrows indicating the specific direction of this bending movement. This view helps illustrate how the catheter’s 1 shape changes based on the pull wire adjustments.

[0090] Figure 4 a cross-sectional view of the distal end 3 of the catheter 1 displaying the coolant movement across the inflow channel 9 and outflow channel 10. The inflow channel 9 is the pathway through which coolant enters the catheter 1, while the outflow channel 10 is where the coolant exits after circulating through the catheter 1.

[0091] The junction 24 between the inflow and outflow channels 9, 10 is made with laser cutting to accurately control the dimensions. The arrow in the Figured indicates the movement of the coolant 25.

[0092] The coolant 25 flows efficiently, maintaining optimal temperature control in the catheter 1. The absence of adhesive and the precision of laser cutting contributes to a smooth junction 24 between the inflow 9 and outflow channels 10, reducing the risk of blockages or failures.

[0093] Figure 5 also illustrates the distal end of the catheter 1 designed for micro wave ablation. The catheter tip 6, located at the furthest end functioned for insertion into the body of the subject. It is formed by reflowing (melting) the multi-lumen tubing in a preformed die without adding any extra material, ensuring the distal end 3 remains free of air bubbles or joint failures. The microwave antenna 5 located near the tip structure 6 is responsible for generating the microwave energy used in the ablation process.

[0094] There is a guide wire 8 to assist in positioning the catheter 1 accurately within the body. The internal irrigation flow represents the movement of coolant 25 within the catheter 1, entering through the inflow channel 9, circulating around the microwave antenna, and exiting through the outflow channel 10. This efficient cooling process ensures optimal temperature control during ablation.

[0095] The sensing wire distal seal 19 ensures there are no leaks or blockages, contributing to the smooth flow of coolant 25 within the catheter 1.

[0096] Referring to Figure 6 that illustrates an ablation catheter 1 comprising the following components.

[0097] A catheter body 2 with a fluid passage (not shown in this figure), featuring both a distal end 3 and proximal end 4. The distal end 3 is equipped with a microwave antenna 5 connected to a microwave generator 12, delivering microwave energy for tissue ablation.

[0098] The antenna 5 is constructed using materials material that can withstand high temperatures and resist damage from microwave energy including but not limited to standard coaxial cables with at least 50 Ohm impedance. The material may be selectedfrom the group of Fluorinated ethylene propylene (FEP) or Polyester PET film backed Copper foil.

[0099] The antenna cooling system 5 includes a coolant pump (not shown in this figure) for directing coolant fluid from the proximal end 4 of the internal in-flow lumen 9 to the distal end 3 of the internal in-flow lumen 9 in which the coolant fluid 25 exiting from the distal end 3 of the internal in-flow lumen 9 then contacts the microwave antenna 5 prior to entering the distal end 3 of the internal out-flow lumen 10 and then the heat exchanged coolant fluid exits the proximal end 4 of the internal out-flow irrigation lumen 10 . This cooling mechanism directs a cool irrigation fluid or a saline fluid around the microwave antenna 5 to prevent overheating and ensure effective ablation. The cool irrigation fluid may have a temperature of around 20 °C.

[0100] The cooling pump (not shown in this figure) is in electrical and / or wireless communication with a controller (not shown) which dynamically adjusts the flow rate of the cooling fluid to the microwave antenna 5 when predetermined temperature thresholds are sensed by the thermocouple, in which the flow rate may range between 30 ml / min - 100 ml / min of the directing cooling fluid into the first internal irrigation lumen or the first internal in-flow irrigation lumen. It may be appreciated that the flow rate may increase higher than 100 ml / min for emergency cooling of the micro wave antenna 5.

[0101] The cooling fluid may be refrigerated to achieve better cooling effect both on catheter and the tissue contact region of the catheter, preventing the ablation heat effect to blood, thereby reducing potential blood clotting.

[0102] The thermocouple in the return irrigation lumen can be utilized to control the cooling pump. Based on the output temperature, the irrigation flow can be automatically adjusted to maintain optimal conditions.

[0103] Additionally, the distal end 3 of the catheter 1 features a tapered tip structure 6 that extends beyond the microwave antenna 5 to accommodate a guide wire 8 extending through a guide wire lumen or the fluid passage (not shown) in the catheter body 2.

[0104] The tip structure 6 may be designed for precise positioning the distal end 3 of the catheter body 2 when ablating tissue. The tip structure 6 may have a triangular profile. The tip structure may have a rounded tip.

[0105] The proximal end 4 of the catheter body 2 may be equipped with an array of connectors 9, 10, 11, 12, 13, 14 for various components, including the guide wire, microwave system, electrode(s), coolant inflow and outflow and saline pressure.

[0106] The catheter 1 further comprises a first elongate tubular member 15 and a second elongate tubular member 16.

[0107] The first elongate tubular member 15 has a proximal end portion defining a proximal end 15A and a distal end portion defining a distal end 15B. The first tubular member 15 may have one or more lumens (not shown) extending between the proximal end 15A and the distal end 15B.

[0108] A second elongate tubular member 16 is received in the lumen of the first tubular member 15. In this embodiment, the second tubular member 16 is slidable axially in the lumen of the first tubular member 15. The second tubular member 16 also includes a proximal end portion defining a proximal end 16A and a distal end portion defining a distal end 16B. The second tubular member 16 defines a lumen extending between the proximal end 16A and the distal end 16B.

[0109] The first tubular member 15 includes a knob-like control mechanism 17 at its proximal end 15 A, allowing for precise movement, deflection, and positioning of the catheter 1 within the subject’s body. It also consists of multiple lumens to house essential components such as the microwave antenna 5 and electrodes 7 in the device 1.

[0110] The catheter 1 further includes least one lumen defined between the proximal end 15A and the distal end 15B of the first elongate member 15. There is one lumen arranged between the proximal end 16A and the distal end 16B of the second elongate tubular member 16.

[0111] Furthermore, within the catheter 1 there is a catheter shaft (not shown) extending from the proximal end 4 to the distal end 3 of the catheter 1 and a catheter sheath (not shown) that surrounds and protects the catheter shaft (not shown).

[0112] A form of lubricious coating is applied to the vascular surface of the catheter 1 to improve smoothness and minimize friction, thereby reducing the risk of blood clot (thrombus) formation.

[0113] Additionally, the operating mechanism is the form of a knob 17 that is axially slidable on the handle 18 of the catheter 1. This knob 17 like control mechanism controls the movement, deflection, or positioning of the catheter 1 withing the body of the subject. The axial movement of the knob 17 effects finer adjustment of position of the first tubular member 15 and the second tubular member 16 relative to each other.

[0114] As above, Figure 7 represents the arrangement of the micro wave catheter system 20 and its associated equipment, arranged for procedural use.

[0115] This setup includes the microwave catheter 1 itself, fully assembled and connected to a range of essential components. The setup includes six connectors coupled to the proximal end of the catheter body.

[0116] First connector 12 is the microwave generator connector to provide the necessary microwave energy.

[0117] Second and third connector is for the coolant system comprising a coolant inflow connector 9 for introducing coolant into the system and a coolant outflow connector 10 for regulating its exit, ensuring proper temperature control.

[0118] Additionally, there is a fourth connector 14 to which a saline pressure infuser bag is connected to maintain the required pressure within the catheter.

[0119] The catheter includes a fifth connector 11 connecting an electrophysiology system, in which the electrophysiology system can be configured for sensing, mapping, pacing, and / or ablating tissue via or using pulse field energy. The fifth connector 11 may interface with the at least one electrode(s) 7 for real-time monitoring and control in which the at least one electrode 7 are located on the outer periphery of the catheter 1.

[0120] The sixth connector 13 is a guide wire inlet connector for positioning the guide wire 8 within the catheter body 2.

[0121] All these components are interconnected at the proximal end 4 of the catheter body 2, enabling a fully operational and coordinated system ready for use.

[0122] Referring to Figure 8 and 9 that illustrates side sectional views of the distal tip 6 of a catheter body 2.

[0123] Figure 8 depicts the tapered tip structure 6 of the catheter 1 with four electrodes 7 positioned on the outer periphery of the structure. The catheter 1 of Figure 8 is deflectable catheter since it does not have guidewires.

[0124] The electrodes 7 may be spaced equidistantly from each other and serially arranged along distal end 3 of the catheter 1.

[0125] The catheter 1 includes at least four electrodes 7 and can accommodate up to ten electrodes. The electrodes 7 may be a curved electrode around on an outer periphery section or portion of the catheter 1. Depending on the use, for example but not limited to if wanting to map between two regions of tissue at the same time, it may be appreciated that further electrodes can be arranged on the outer periphery of the catheter 1.

[0126] While Figure 9 is similar to Figure 8, Figure 9 specifically illustrates the distal end 3 of a catheter 1 equipped with a retractable guidewire 8 and the tapered tip structure 6. The guidewire 8 can be retracted into the catheter 1 to avoid any issues during the procedure. There guidewire lumen (not shown) may be flushable with saline irrigationfluid so that blood does not coagulate or block the lumen during or after use. It is crucial that the guidewire 8 is controlled such that it does not protrude from the catheter 1 when microwave energy is applied, as the guidewire 8 can heat up, potentially leading to complications.

[0127] Prior to the ablation process, the guidewire 8 is behind the electrode 7 to ensure effective and safe energy delivery. However, for catheters utilizing Pulsed Field Ablation (PF A) energy, the guidewire 8 may remain in any position during the ablation process without affecting the procedure's safety or effectiveness.

[0128] Figure 10 is a sectional view of the first thermocouple 21. This thermocouple 21 measures the temperature of the return irrigation fluid for assessing the cooling efficacy of the micro wave antenna 5. By monitoring this temperature, it is possible to detect any anomalies that may indicate the antenna 5 is radiating incorrectly and heating the wrong location.

[0129] If the temperature of the return irrigation fluid exceeds a certain threshold, for example exceeding 38 °C, it may signal a potential issue with the ablation process and the controller (not shown) may dynamically adjust the flow rate of the cooling fluid to cool the microwave antenna 5 to a predetermined or an optimum safe temperature. The thermocouple wire (not shown) can be routed to the electrical wire lumen 22, ensuring accurate temperature readings are relayed for effective monitoring.

[0130] Figure 11 similar to Figure 10 sectional view depicting the placement of the second thermocouple 23 close to the distal electrode 7.

[0131] Another thermocouple 23 of Figure 11 is adhered to the inner surface of the electrode 7 and measures the temperature of the blood flowing over the catheter 1 when the catheter 1 makes contact with tissue. This measurement is essential in determining the heat distribution, specifically how much heat is being absorbed by the blood rather than the target tissue.

[0132] Additionally, high temperature readings from this thermocouple 23 may indicate that the ablation might be occurring at an incorrect location.

[0133] Figures 12A through 15B provide cross-sectional views of the catheter's 1 internal structures, each highlighting specific components and configurations at different positions within the multi-lumen catheter tube 26.

[0134] Specifically, Figure 12A illustrates a cross-sectional view of the distal end 3 of the catheter 1 highlighting the coolant inflow 9 and outflow channels 10, and the positioning of the micro wave antenna 5. This figure explains how coolant 25 circulates around the antenna 5 to maintain optimal temperature control during the procedure. The left arrow indicates coolant inflow 9, whereas the right arrow indicates coolant outflow 10.

[0135] Figure 12B provides a sectional view of the coolant inflow 9 and outflow 9 in the separate lumens within the multi-lumen catheter tube 26 and position of the antenna 5. This design features a central lumen surrounded by two equally sized lumens on either side. Additionally, it includes a large ring structure and a smaller ring structure, which contains two dotted circular features within it. The lumen is divided along the Y-axis into two halves, offering a detailed view of the internal arrangement and structural elements.

[0136] Figure 13A depicts a cross-sectional view showing the positioning of the sensing wire lumen 19 and guide wire lumen within the catheter 1. It demonstrates how these lumens are arranged relative to each other and other internal structures.

[0137] Figure 13B depicts a sectional view of the sensing wire 19 and guide wire passing through separate individual lumens within the multi-lumen catheter tube 26. This design features a central lumen on the left side, flanked by two equally sized lumens on either side. Additionally, it incorporates a large ring structure and a smaller ring structure with two dotted circular features inside it. The lumen is divided along the Y-axis into a 3 / 4 portion, providing a detailed view of the internal arrangement and structural components.

[0138] Figure 14A highlights a cross-sectional view of the catheter 1 with braided catheter shaft 27. This figure illustrates how the braided design contributes to the catheter's overall durability and maneuverability.

[0139] Figure 14B depicts a sectional view of the multi-lumen catheter tube 26 joint with braided catheter shaft tube 27. This design features a central lumen encircled by two equally sized lumens on either side, with two smaller lumens positioned within the central lumen. Additionally, the design includes a large ring structure that surrounds the central lumen. The lumen is divided along the Y-axis into two halves, providing a detailed view of the internal arrangement and structural elements.

[0140] Figure 15A illustrates a cross-sectional view of the distal end of the catheter 1, highlighting the ring electrode 31. In the figure there includes a ring electrode sensing wire 28, a ring electrode joint sensing wire 29 and a ring electrode 30 attached to the outside of multi-lumen catheter tube. The figure shows the joint where the ring electrode is attached to the electrode sensing wire 28, ensuring a secure connection for sensing purposes.

[0141] Figure 15B depicts a sectional view of the ring electrode 31 with the sensing wire 28 passing through the inside of one of the individual lumens of the catheter shaft 27, demonstrating an alternative configuration.

[0142] Figure 16 shows a schematic view of the proximal end of the multi-lumen tube 26 A . This end of the tube 31 is where it connects to another device or system for the introduction or extraction of fluids or substances.

[0143] The multi-lumen tube 26 of Figure 16 consists of multiple internal channels (lumens) within a single outer tube, with the cross-section having four distinct lumens 32, 33, 34, 35.

[0144] Referring to Figure 17 that provides a detailed view of the assembly process for the multi-lumen tube 26, involving lumen inserts 36 and over-molded plastic 37. Themulti-lumen tube's proximal end 26A, with its multiple internal channels, is encased in over-molded plastic 37. The over-molded plastic 37 enhances structural integrity and ensures a secure connection. A lumen inserts mandrel 36 is used during the over-molding process to position and support the lumen inserts, ensuring they are correctly aligned and maintained in the desired configuration.

[0145] Figure 18 provides a cross-sectional view of the distal end 2 of the catheter 1, showing the placement of the pressure sensor 44 within the lumen. The pressure sensor 44 may be strategically positioned on the peripheral distal surface of the catheter 1. This sensor monitors blood pressure in close proximity to the electrodes 7, enabling more precise data collection and better integration of pressure measurements with electrode functionality.

[0146] The primary function of a lumen inserts mandrel is to support the internal diameter of the tube. This helps maintain precise lumen dimensions, which is critical for the functionality of the catheter.

[0147] Mandrels can be made from various materials, including metal (e.g., stainless steel, titanium), plastic, or other suitable materials that can withstand the manufacturing conditions without degrading or deforming.

[0148] The catheter system comprises a catheter 1 , a handle 18 that has a proximal end 16A and a distal end 16B and the catheter 1 extends from the distal end 16B of the handle; and an operating mechanism carried by the handle 18 for effecting relative displacement between the first tubular member 15 and the second tubular member 16 . The operating mechanism comprises a knob 17 that is axially slidable on the handle body 18.

[0149] Referring to Figure 19 which is a schematic view of the control system arrangement for the microwave ablation catheter. The system is specifically configured to monitor and control temperature and coolant flow within the catheter for determining closed-loop thermal ablation optimization.

[0150] Within the figure, the catheter structure is represented by two cylindrical sections, with an upper section having a first thermocouple 21 routed to the electrical wire lumen 22and a lower section having a second thermocouple 23. Both the first thermocouple 21 and the second thermocouple 23 are integrated into the catheter structure to monitor temperatures, providing real-time temperature data. A coaxial cable 50 extends through the catheter structure, connecting these thermocouples 21 and 23 to a machine learning model 51.

[0151] The machine learning model 51 is configured to manage various operational parameters of the ablation system, receiving temperature data from thermocouples 21 and 23. It incorporates a dual-flow configuration for simultaneous energy delivery and temperature regulation.

[0152] The flow of microwave power 54, indicated by an arrow pointing towards thermocouple 21 and also originating from the ML model 51, enables energy delivery to the ablation site. Additionally, a flow of coolant 55 indicated by an arrow on the lower section pointing towards thermocouple 23 and also originating from the ML model 51, facilitates temperature regulation within the catheter and at the ablation site.

[0153] In the figure, there includes a tip temperature measurement 52, which gauges the temperature at the distal end of the catheter where ablation occurs, providing critical feedback on actual treatment site temperature. Furthermore, there is an outflow temperature measurement 53 that tracks the coolant temperature as it exits the catheter, indicating the amount of heat removed from the ablation site. The machine learning model receives real-time temperature data from the the tip temperature 52 and outflow temperature measurement 53.

[0154] Based on data received, the ML model 51 continuously optimizes both the microwave power delivery 54 for precise temperature control and the cooling fluid flow rates 55 and may be configured to predict tissue temperature and the size of the ablation zone.

[0155] Referring to Figure 20, a system diagram 60 that illustrates the arrangement of components within the catheter system. The system 60 comprises four electrodes 7 connected to an impedance data input 61 which is further connected to a controller with impedance monitoring system 62. This controller 62 is configured to detect real-time changes in tissue impedance and provide crucial feedback. Based on these impedance changes, the controller 62 adapts various ablation parameters, indicated by arrow including microwave power, duration, and cooling fluid flow rate. This adaptive control ensures consistent lesion formation by accounting for tissue variations.

[0156] The controller is configured to receive real-time temperature data from the first and second thermocouples in order to monitor the tissue undergoing ablation. The controller further employs a predictive algorithm or machine learning model to continuously optimize microwave power delivery and cooling fluid flow rate. This continuous optimization is performed to achieve a desired ablation lesion size and shape while simultaneously minimizing collateral tissue damage.

[0157] The predictive algorithm embedded within the controller actively monitors realtime temperature data from both the thermocouples during renal denervation surgery. This is crucial for patient safety, as a tip temperature reaching 50°C may lead to complications such as thrombus formation due to excessive heat.

[0158] Hence, in order to prevent such issues, the algorithm is designed to ensure the tip temperature never exceeds 45°C. This is achieved by continuously and dynamically adjusting the flow rate and microwave power. As the tip temperature approaches the 45°C threshold, the algorithm proportionally increases the water flow and reduces the microwave power, thereby maintaining a safe operating temperature.

[0159] The relationship between flow rate (m), microwave power (related to heat Q), can be described by the formula: m=Cp(t2-tl)nQ,where t2— tl represents the temperature difference between the outflow and inflow, Q is heat directly corelated with microwave power and n is efficiency of the radiator

[0160] Beyond this real-time control, the system incorporates a safety mechanism. Given that high microwave power can also cause tissue damage, the controller collects extensive datasets of these operational parameters. This data can then be used to train an Al model, enabling more sophisticated and collective management of the outputs for enhanced patient safety and surgical efficacy.

[0161] Referring to Figure 21, a system diagram 70 which is a further extension of the system illustrated in Figure 20.

[0162] At the top of the figure, a catheter is shown with four electrodes 7. Below this, the system incorporates two primary processing blocks a microwave block 71 and a PFA (Pulsed Field Ablation) block 72. These blocks are functionally connected via control lines to a central controller unit 62, positioned below them.

[0163] At the bottom there is an Input from GUI (Graphical User Interface) block 73 serving as the interface for user input. This control architecture demonstrates how user input is managed and propagated throughout the system. The Input from GUI block 73 feeds directly into the Controller unit 62, allowing user commands and parameters to be transmitted to the core control logic. The controller 62 thereafter orchestrates the operations of both the microwave ablation and pulsed field ablation functionalities, enabling comprehensive and user-driven management of the ablation procedure.

[0164] This adaptation of the ablation parameters accounts for variations in tissue type, water content, and blood flow, ensuring consistent lesion formation across different tissue environments.

[0165] Furthermore, the direct integration of the impedance monitoring mechanism and linkage to adaptive microwave ablation parameters, specifically for tissue-optimizationrepresents an advanced feature that enhances the precision and consistency of the ablation procedure.

[0166] While the catheter has been described in the context of renal denervation, it should be noted that it is also applicable for other procedures, such as cardiac ablation.

[0167] In specific embodiments, the multi-lumen catheter features dedicated empty lumens for contrast injection, facilitating enhanced fluoroscopic imaging. The present design provides the advantage of precise contrast delivery directly through the catheter. This allows for optimized control over contrast injection, enabling more accurate imaging and better procedural guidance based on the catheter’s exact placement.

[0168] While the catheter has been described in the context of renal denervation, it should be noted that it is also applicable for other procedures, such as cardiac ablation.

[0169] While only 4 electrodes have been shown, this is purely for illustration purposes and the catheter could carry up to 10 electrodes.

[0170] The advanced catheter design offers several key advantages It ensures cooling control by containing the cooling irrigation fluid within the catheter, allowing for accurate adjustment of the flow rate.

[0171] Additionally, the internal irrigation system eliminates the risk of coagulated blood obstructing throughout the procedure, improving efficiency and reducing blockage of irrigation lumens resulting in no flow of fluid and overheating of microwave antenna.

[0172] The design also prioritizes biocompatibility by keeping the irrigation fluid entirely within the catheter, thereby minimizing the risk of adverse reactions associated with external materials. Furthermore, the catheter’s robust construction, free from glue joints in the distal section, reduces the risk of air bubbles weakening the sheath and potentially causing bursts during ablation.

[0173] It will be appreciated by person skilled in the art that numerous variations and / or modifications may be made to the described embodiments without departing from the broadly described scope. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A catheter adapted for delivering microwave energy in ablating tissue, the catheter comprising: a catheter body having a distal portion and a proximal portion; a microwave antenna positioned between a first internal lumen and a second internal lumen, and located within the distal portion of the catheter body, wherein the microwave antenna is in electrical communication with a microwave generator to deliver microwave energy to the antenna; an antenna cooling system comprising; an external coolant pump for directing cooling fluid from the first internal lumen to the second internal lumen, wherein the cooling fluid from the first internal lumen contacts the microwave antenna prior to entering the second internal lumen; and a first thermocouple positioned in the second internal lumen and in communication with the external cooling pump, wherein the external cooling pump is configurated to dynamically adjust the flow rate of the cooling fluid to the microwave antenna when predetermined temperature thresholds are sensed by the thermocouple.

2. The catheter of Claim 1, wherein the flow rate of the cooling fluid is between 30 ml / min- lOOml / min.

3. The catheter of Claim 1, wherein the first internal lumen is an internal in-flow lumen and the second internal lumen is an internal out-flow lumen.

4. The catheter of Claim 1, wherein the catheter includes at least one electrode located on the outer periphery of the catheter, wherein the electrode is configured to perform at least one function from the group of: sensing, pacing, mapping, and ablation.

5. The catheter of Claim 1, wherein the catheter further comprises a second thermocouple positioned at the electrode located on the outer periphery of the catheter.

6. The catheter of Claim 1, wherein the first thermocouple is configured to monitor the cooling efficiency of the microwave antenna.

7. The catheter of Claim 5, wherein the second thermocouple is configured to measure the temperature of the blood or tissue.

8. The catheter of Claim 1 , wherein the catheter further comprises a guide wire lumen extending from the proximal end to the distal end, wherein the guide wire lumen allows for a guide wire to extend therethrough.

9. The catheter of Claim 1, wherein the micro wave antenna is compatible with standard coaxial cables having a diameter of about 1.13 mm with an impedance value of about 50 Ohms.

10. The catheter of Claim 1, wherein the antenna cooling system is in fluid communication to a proximal end of the first internal lumen.

11. The catheter of Claim 1, wherein the catheter comprises a lubricious coating to the outer surface of the catheter.

12. The catheter of Claim 1, wherein the microwave ablation catheter operates at a frequency ranging between 300 MHz to 300 GHz, preferably between 2 GHz to 3 GHz,13. The catheter of Claim 12, wherein the micro wave ablation catheter operates at a frequency of 2.45 GHz14. The catheter of Claim 1, wherein the micro wave antenna may be selected from the group consisting of monopole, dipole, slotted, or quarter-wavelength antennas15. The catheter of any one of Claims 1 to 14, wherein the catheter body comprises; a first elongate tubular member having a proximal end portion and distal end portion, and houses a second elongate tubular member and contains plurality of lumens; wherein the second tubular member includes a proximal end portion and a distal end portion extending from the distal end of the first tubular member; a catheter shaft extending from the proximal end to the distal end of the catheter; and a knob-like control mechanism attached to the proximal end of the first tubular member, wherein the knob-like control mechanism is configured to control the movement, deflection, or positioning of the catheter within the body of the subject.

16. The catheter of Claim 15, wherein there includes at least one lumen defined between the proximal end and the distal end of the first elongate member.

17. The catheter of Claim 15, wherein there includes at least one lumen defined between the proximal end and the distal end of the second elongate tubular member.

18. The catheter of Claim 15, wherein catheter comprises a catheter sheath that surrounds and protects the catheter shaft.

19. The catheter of Claim 15, wherein the catheter further comprises: a handle, wherein the handle includes aa proximal end and a distal end and the catheter device extending from the distal end of the handle; an operating mechanism for effecting relative displacement between the first elongate tubular member and the second elongate tubular member of the catheter device.

20. The catheter of Claim 19, wherein the operating mechanism is a knob that is axially slidable on the handle of the catheter body.

21. The catheter of Claim 19, wherein the catheter has a length of about 900 mm.

22. The catheter of Claim 19, wherein the catheter may or may not be deflectable.

23. The system of Claim 19, wherein a guide wire lumen is not required if the catheter is deflectable.

24. The system of Claim 19, wherein the guide wire lumen is required if the catheter is not deflectable.

25. The system of Claim 19, wherein the distal end of the first tubular member and the distal end of the second tubular member are joined through a process of plastic welding.

26. The system of Claim 19, wherein the material of the first tubular member and the second tubular member is Polyether block amide (PEBAX).

27. The system of Claim 19, wherein the tip of the catheter may bend bidirectionally at an angle ranging between 0 to ±90 degrees for an effective ablation procedure.

28. The system of Claim 19, wherein the catheter is configured with an integrated pressure sensor designed for direct measurement of blood pressure.

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