Soft balloon devices and systems

Abstract

A device, system, and method for safely performing various treatment procedures using a single treatment device. For example, a system is provided that includes a treatment device having a highly compliant balloon that is inflated at a constant pressure and remains soft during use, which enhances balloon-tissue contact, treatment efficacy, and patient safety. In one embodiment, a system for ablating tissue includes: a treatment device including a highly compliant balloon; a control unit including a fluid supply reservoir in fluid communication with the highly compliant balloon, the control unit being configured to deliver fluid from the fluid supply reservoir to the highly compliant balloon such that the highly compliant balloon is maintained at a balloon pressure between 0.2 psig and 3.0 psig.

Description

Technical Field

[0001] The present invention relates to a device, system and method for safely performing various treatment procedures using a single treatment device. For example, a system is provided that includes a treatment device with a highly compliant balloon that inflates at a constant pressure and remains "soft" during use, which enhances balloon-tissue contact, treatment efficacy and patient safety. Background Art

[0002] Cardiac arrhythmias are conditions that affect the normal rhythm of the heart and affect millions of people. Certain types of arrhythmias, including ventricular tachycardia and atrial fibrillation, can be treated using one or more energy modalities such as endocardial or epicardial cryoablation.

[0003] The effectiveness of an ablation procedure may depend largely on the quality of contact between the therapeutic element of the medical device and the heart tissue. Surgical procedures such as pulmonary vein isolation (PVI) are commonly used to treat arrhythmias, such as atrial fibrillation. In such surgical procedures, a therapeutic element such as a cryoballoon may be positioned at the ostium of a pulmonary vein so as to create a circumferential lesion around the ostium. However, the success of the procedure depends largely on the quality of the lesion(s) created during the procedure and whether the cryoballoon has completely blocked the pulmonary vein. For example, a complete circumferential lesion is only created when the cryoballoon has completely blocked the pulmonary vein. On the other hand, incomplete blockage allows blood to flow out of the pulmonary vein being treated, through the cryoballoon, and into the left atrium of the heart. Warm blood flow may prevent the cryoballoon from reaching a sufficiently low temperature to create a permanent lesion in the target tissue. Generating a reversible lesion may not be sufficient to achieve electrical isolation, and as a result, heart disease is likely to recur.

[0004] When performing PVI, it may also be difficult to prevent the therapeutic element from moving too deep within the pulmonary vein while applying sufficient pressure through the elongated body of the device to ensure adequate contact between the therapeutic element and the ostium of the pulmonary vein. Tissue ablation within the pulmonary vein may lead to complications such as cardiac tamponade and pulmonary vein stenosis, in which the pericardial sac surrounding the heart fills with blood.

[0005] In addition, in a single ablation procedure, therapeutic elements of different sizes, shapes, and configurations may all be required. For example, an ablation procedure may involve PVI and linear ablation patterns. To accomplish this, the physician may employ several different catheters having variations in the geometry and / or size of the therapeutic elements in order to produce the desired ablation pattern. Each device may have a unique geometry for producing a specific lesion pattern, wherein multiple catheters are removed and replaced in sequence to produce the desired lesion. However, replacing various devices during the surgical procedure may result in inaccurate placement and positioning or movement of the distal tip relative to the target tissue, and may further increase the time required to perform the surgical procedure, and may increase the risk of injury and discomfort to the patient. Even if a single device includes therapeutic elements that can be converted between configurations to provide many different ablation patterns, it is physically challenging to convert the therapeutic elements without displacing the device from the treatment site. Summary of the invention

[0006] The present invention advantageously provides a device, system and method for safely performing different treatment procedures using a single treatment device. For example, a system is provided that includes a treatment device having a highly compliant balloon that inflates at a constant pressure and remains "soft" during use, which enhances balloon-tissue contact, treatment efficacy and patient safety.

[0007] In one embodiment, a system for ablating tissue includes: a treatment device comprising a highly compliant balloon; and a control unit including a fluid supply reservoir connected to the highly compliant balloon fluid, the control unit being configured to deliver fluid from the fluid supply reservoir to the highly compliant balloon so that the highly compliant balloon is maintained at a balloon pressure between 0.2 psig (pounds per square inch gauge) and 3.0 psig.

[0008] In one aspect of this embodiment, the control unit is configured to maintain the balloon pressure between 0.2 psig and 3.0 psig during inflation of the highly compliant balloon.

[0009] In one aspect of this embodiment, the control unit is configured to maintain the balloon pressure between 0.2 psig and 3.0 psig during tissue ablation.

[0010] In one aspect of this embodiment, the system further comprises: a vacuum source; a fluid delivery conduit between the fluid supply reservoir and the highly compliant balloon; and a fluid return conduit between the highly compliant balloon and the vacuum source.

[0011] In one aspect of this embodiment, the system also includes: a flow control valve, which is fluidly connected to the fluid delivery pipeline; and a pressure control valve, which is fluidly connected to the fluid return pipeline, and the control unit is configured to selectively adjust the flow control valve and the pressure control valve to maintain the balloon pressure between 0.2psig and 3.0psig.

[0012] In one aspect of this embodiment, the system further comprises: a pitot tube at least partially disposed within the highly compliant balloon; and a pressure sensor in communication with the pitot tube. In one aspect of this embodiment, the control unit is configured to determine the balloon pressure based on the pressure measurements recorded by the pressure sensor. In one aspect of this embodiment, the control unit is configured to determine the static pressure within the highly compliant balloon based on the stagnation pressure recorded within the highly compliant balloon.

[0013] In one aspect of this embodiment, the therapeutic element also includes a pressure sensor within the highly compliant balloon, which is connected to the control unit and is configured to record a pressure signal generated by the heartbeat, and the control unit is configured to determine the occlusion state of the highly compliant balloon based on the pressure signal recorded by the pressure sensor.

[0014] In one aspect of this embodiment, the treatment device further comprises: an elongated body having a proximal portion and a distal portion; a shaft slidably disposed within the elongated body; a handle fixedly coupled to the proximal portion of the elongated body; and an actuator element mechanically connected to the shaft and at least partially disposed within the handle, the actuator element and the shaft being freely movable relative to the handle and the elongated body. In one aspect of this embodiment, the shaft has a proximal portion and a distal portion, the highly compliant balloon has: a proximal neck coupled to the distal portion of the elongated body; and a distal neck coupled to the distal portion of the shaft, retraction of the actuator element from an initial position transitions the highly compliant balloon between a first configuration and a second configuration, and extension of the actuator element from the initial position transitions the highly compliant balloon between the first configuration and a third configuration.

[0015] In one aspect of this embodiment, the first configuration is an at least substantially circular configuration. In one aspect of this embodiment, the highly compliant balloon is expandable to a first outer diameter when in the first configuration, and is further expandable to a second outer diameter when in the first configuration. In one aspect of this embodiment, the first outer diameter is approximately 23 mm and the second outer diameter is approximately 36 mm.

[0016] In one aspect of this embodiment, the second configuration is an annular configuration.

[0017] In one aspect of this embodiment, the third configuration is an elongated configuration.

[0018] In one embodiment, a system for ablating tissue includes: a treatment device, the treatment device comprising: a slender body having a distal portion and a proximal portion; a shaft slidably configured within the slender body, the shaft having a proximal portion and a distal portion; a highly compliant balloon, the balloon having a distal neck and a proximal neck, the distal neck being connected to the distal portion of the shaft, and the proximal neck being connected to the distal portion of the slender body; a control unit, the control unit comprising: a processing circuit, a coolant supply reservoir, and a vacuum source; a fluid delivery conduit between the coolant supply reservoir and the highly compliant balloon; and a fluid return conduit between the highly compliant balloon and the vacuum source, the processing circuit being configured to regulate the coolant flow through the fluid delivery conduit and the fluid return conduit to maintain the highly compliant balloon at a balloon pressure of 0.2 psig to 3.0 psig during the inflation phase and the ablation phase, the processing circuit being further configured to control the balloon pressure independently of the flow rate of coolant from the coolant supply reservoir.

[0019] In one aspect of this embodiment, the system also includes: a flow control valve connected to the fluid delivery pipeline fluid; and a pressure control valve connected to the fluid return pipeline fluid, the processing circuit being configured to control the flow control valve and the pressure control valve and the vacuum source to maintain the balloon pressure between 0.2psig and 3.0psig.

[0020] In one embodiment, a method for performing a medical procedure includes: selecting a desired expansion size for a balloon of a treatment device; delivering fluid to the balloon and withdrawing coolant from the balloon so that the balloon expands to a desired size and has a pressure between 0.2 psig and 3.0 psig; delivering coolant to the balloon at a certain flow rate and maintaining the balloon at a pressure between 0.2 psig and 3.0 psig, the pressure being controlled independently of the flow rate of the coolant, the delivery of coolant to the balloon reducing the temperature of the balloon to a temperature sufficient to cryoablate tissue; positioning the treatment device so that the balloon contacts a target tissue area; and using the balloon to cryoablate the target tissue area.

[0021] In one aspect of this embodiment, the method further includes: continuously monitoring the pressure within the balloon; and regulating the flow of coolant to and from the balloon by adjusting at least one of a flow control valve and a pressure control valve, wherein adjusting at least one of the flow control valve and the pressure control valve is independent of regulating the flow rate of the coolant.

[0022] As required, detailed embodiments of the present disclosure are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the present invention that can be implemented in various forms. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching a person of ordinary skill in the art to apply the present invention differently with virtually any appropriate detailed structure. Further, the terms and phrases used herein are not intended to be limiting; rather, they are intended to provide an understandable description of the present invention. The present invention may be better understood by considering the following description in conjunction with the accompanying drawings. The accompanying drawings are not drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be more fully understood, and the attendant advantages and features thereof will be more readily appreciated, by referring to the following detailed description considered in conjunction with the accompanying drawings, in which:

[0024] Figure 1 An exemplary medical system is shown that includes a medical device having a highly compliant balloon;

[0025] FIG2 shows a cross-sectional view of an elongated body of a currently known medical device;

[0026] Figure 3 showing a cross-sectional view of an elongated body of a medical device disclosed herein;

[0027] Figure 4 Exemplary medical devices such as Figure 1 A cross-sectional view of the medical device shown in;

[0028] Figure 5 Shows Figure 1 A schematic diagram of an exemplary medical system;

[0029] Figure 6 showing a highly compliant balloon having a first outer diameter in a first expanded configuration;

[0030] Figure 7 showing a highly compliant balloon in an expanded first configuration having a second outer diameter;

[0031] Figure 8 A graph of balloon diameter versus inflation pressure is shown;

[0032] Fig. 9 showing a graph of tissue contact surface area on a balloon versus inflation pressure;

[0033] Fig.10 shows a front view of a currently known balloon and an exemplary tissue contact area on the distal side of the currently known balloon;

[0034] Fig.11 shows a front view of a medical device having a highly compliant balloon disclosed herein in an expanded first configuration and an exemplary tissue contacting region on a distal surface of the highly compliant balloon;

[0035] Fig.12 shows a side view of an exemplary highly compliant balloon in an expanded first configuration and in contact with a target tissue area;

[0036] Fig.13 Shows when Fig.11 a contact surface of the highly compliant balloon when the highly compliant balloon is in an expanded first configuration and in contact with a region of target tissue;

[0037] Fig.14 showing a side view of an exemplary highly compliant balloon in an expanded second configuration;

[0038] Fig.15 and 16 They are shown respectively Fig.13 a highly compliant balloon and a contact surface of the highly compliant balloon when the highly compliant balloon is in an expanded second configuration and in contact with a target tissue region;

[0039] Fig.17 showing an elevational view of an exemplary highly compliant balloon in an expanded second configuration and an exemplary tissue contacting region on a distal side of the highly compliant balloon when the distal surface of the highly compliant balloon contacts a region of target tissue;

[0040] Fig.18 shows a side view of an exemplary highly compliant balloon in a delivery configuration;

[0041] Fig.19 shows a side view of an exemplary highly compliant balloon in an expanded third configuration and in contact with a target tissue area;

[0042] Fig. 20 Shows when Fig.19 an exemplary tissue contacting region of the highly compliant balloon when the highly compliant balloon is in an expanded third configuration and in contact with a target tissue region;

[0043] Fig.21 A graph of pressure over time for assessing vascular occlusion is shown;

[0044] Figure 22-24 Various ways of occluding a blood vessel with a highly compliant balloon are shown;

[0045] Fig.25Shows the manner in which a blood vessel is occluded using a currently known balloon;

[0046] Fig.26 shows a graph comparing the depth into a blood vessel that a distal end of a balloon can travel depending on force; and

[0047] Fig. 27 A flow chart of an exemplary method for performing a medical procedure using a therapeutic device with a highly compliant balloon is shown. DETAILED DESCRIPTION

[0048] The devices, systems and methods disclosed herein are used to treat tissue regions, such as pulmonary vein isolation, point ablation and / or linear ablation with a single treatment device. For example, a system is provided that includes a treatment device having a highly compliant balloon that is inflated at a constant pressure and remains "soft" during use, which enhances balloon-tissue contact, treatment efficacy and patient safety.

[0049] Before describing in detail exemplary embodiments according to the present disclosure, it should be noted that components are appropriately represented in the drawings with conventional symbols and only those specific details relevant to understanding the embodiments of the present disclosure are shown to avoid obscuring the present disclosure due to details that would be obvious to those skilled in the art having the benefit of the description herein.

[0050] As used herein, relative terms such as "first", "second", "top" and "bottom" and similar expressions may be used only to distinguish one entity or element from another entity or element, without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terms used herein are only for describing specific embodiments and are not intended to limit the concepts described herein. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless otherwise clearly stated herein. It should also be understood that the term "comprising" as used herein specifically refers to the presence of the stated features, wholes, steps, operations, elements and / or parts, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, parts and / or combinations thereof.

[0051] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. It should also be understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant field, and will not be interpreted in an idealized or overly formal manner unless explicitly defined in this article.

[0052] In the embodiments described herein, connection terms such as "in communication with..." may be used to indicate electrical or data communication, which may be achieved, for example, by physical contact, induction, electromagnetic radiation, radio signals, infrared signals, or optical signals. It should be understood by those skilled in the art that multiple components may interoperate and may be changed and varied to achieve electrical and data communication.

[0053] Referring now to the drawings, in which like reference numerals refer to like elements throughout the drawings, Figure 1 An embodiment of a medical system is shown in the drawings, which is generally designated "10". Devices and system components are appropriately represented in the drawings with conventional symbols, and only those specific details relevant to understanding the embodiments of the invention are shown, so as not to obscure the disclosure due to details that will be apparent to those skilled in the art with the benefit of the description herein. In addition, although certain embodiments or figures described herein may show features that are not expressly indicated in other figures or embodiments, it should be understood that the features and components of the systems and devices disclosed herein are not necessarily mutually exclusive and may be included in various different combinations or configurations without departing from the scope and spirit of the invention.

[0054] One embodiment of the medical system 10 may generally include a treatment device 12 in communication with a control unit 14. The treatment device 12 may include one or more diagnostic or therapeutic elements 16 for energy interaction or other therapeutic interaction between the treatment device 12 and a treatment site (also referred to as a target tissue region). The (one or more) treatment elements 16 may, for example, deliver cryotherapy, and may also be configured to deliver radiofrequency energy, or in other cases be used to transfer energy to a tissue region near a target tissue region, including cardiac tissue. Specifically, the one or more treatment elements 16 may be configured to reduce the temperature of adjacent tissue in order to perform cryotherapy and / or cryoablation. For example, the treatment element 16 may include one or more balloons 18 (such as Figure 1 ), a cryogenic coolant may be circulated in these balloons to reduce the temperature of the balloons. As discussed in more detail below, when fully inflated, the balloon(s) 18 are configured to be "soft" (i.e., easily deformable and / or conformable to the target tissue area). In addition, the therapeutic element 16 may include other thermally and / or electrically conductive components, such as one or more electrodes in communication with the control unit 14.

[0055] In one embodiment, the treatment device 12 includes an elongated body 20 that is sized and configured to pass through a patient's vascular system and / or to be positioned near an area of ​​tissue for diagnosis or treatment, such as a catheter, cannula, or intravascular introduction. For example, the elongated body 20 may have an outer diameter of 11 French (Fr). The elongated body 20 defines a longitudinal axis 22, a proximal portion 24, and a distal portion 26, and may also include one or more lumens disposed within the elongated body 20 that provide mechanical, electrical, and / or fluid communication between the proximal portion 24 of the elongated body 20 and the distal portion 26 of the elongated body 20. In currently known devices, the elongated body 28 may include a central lumen 30, an outer wall 32, a fluid delivery conduit 36, and a guidewire lumen 37 (e.g., as shown in FIG. 2), with a plurality of smaller lumens 34 extending into the central lumen 30 in the outer wall 32. The central lumen 30 defines a fluid return conduit in the area between the outer wall 32 (and the plurality of smaller lumens 34) and the guidewire lumen 37. However, the extension of the plurality of smaller lumens 34 into the central lumen 30 limits the fluid return conduit. In contrast, the treatment device 12 disclosed herein does not include the plurality of smaller lumens 34, and thus provides a larger fluid return conduit that is capable of draining fluid from the balloon 18 more quickly. For example, Figure 3 As shown, the elongated body 20 includes a central lumen 38, an outer wall 40, a fluid delivery conduit 42, and an optional guidewire lumen 44. The central lumen 38 defines a fluid return conduit 46 in the area between the outer wall 40 and the guidewire lumen 44. In one embodiment, compared to currently known designs, Figure 3 The configuration shown can increase the volume of the fluid return conduit by more than 30%. In addition, the larger volume of the fluid return conduit reduces the pressure drop within the elongated body 20.

[0056] In one embodiment, the treatment device 12 also includes a shaft 48 slidably disposed within the elongated body 20. For example, the shaft 48 is a flexible linear shaft that is longitudinally movable within the lumen of the elongated body 20 (e.g., the central lumen 38 or the guidewire lumen 44). Further, the shaft 48 includes a proximal portion (not shown) and a distal portion 50 having a distal tip 52. The movement of the shaft 48 can affect the shape and configuration of the balloon 18. For example, the shaft 48 can be fully advanced when the balloon 18 is deflated and in a delivery (or first) configuration, in which the balloon 18 has a minimum diameter, which is suitable, for example, for retracting the treatment device 12 into the sheath to be delivered to or removed from the treatment site. Conversely, when the balloon 18 is expanded and in a treatment (or second) configuration, the shaft 48 can be advanced or retracted a distance that affects the size and configuration of the expanded balloon 18, as discussed in more detail herein. Further, the shaft 48 may include a guidewire lumen through which a sensing device, mapping device, guidewire, or other system components may be positioned and extend from the distal end of the treatment device 12.

[0057] As described above, in one embodiment, one or more therapeutic elements 16 include a single expandable element, such as the balloon 18 shown in the figure. However, it will be understood that the treatment device 12 may include more than one therapeutic element 16, electrode or other suitable energy exchange structure or component, and the therapeutic element 16 includes expandable and / or non-expandable therapeutic elements (e.g., an inner balloon surrounded by an outer balloon). Figure 1 In the illustrated embodiment, the therapeutic element 16 includes a balloon 18, such as a cryoballoon, having a proximal neck 54 coupled to the elongated body distal portion 26 and a distal neck 56 coupled to the shaft distal portion 50. In one embodiment, the distal neck 56 is coupled to the shaft distal end 52. The proximal neck 54 and the distal neck 56 of the balloon 18 can be coupled to the elongated body 20 and the shaft 48, respectively, using any suitable means, such as using adhesives, chemical bonding, laser welding, having one or more mechanical coupling elements, etc. Further, the balloon 18 is a compliant or highly compliant balloon composed of one or more materials such as polyurethane, polyolefin copolymer (POC), or other materials that allow the balloon to be "soft" (i.e., easily deformable and / or conform to areas of target tissue) when fully inflated. The compliant or highly compliant balloon 18 is referred to herein as a "highly compliant balloon". In addition, the balloon 18 can be inflated to a first outer diameter (e.g., about 23 mm) and further inflated to a second outer diameter (e.g., about 36 mm) at an inflation pressure between 0.2 psig and 3.0 psig, which is also the pressure of the balloon 18 when the balloon 18 is used in an ablation procedure. In contrast, currently known balloons are inflated at a pressure of about 2 psig, with an ablation pressure of 17.5 psig.

[0058] The treatment device 12 includes one or more nozzles, orifices, or other fluid delivery elements 58 for delivering fluid to the interior chamber 60 of the balloon 18. During operation, coolant may flow from the coolant supply reservoir 62 through the fluid delivery conduit 42 within the elongated body 20 to the distal portion 26, where the coolant may then enter the interior chamber 60 of the balloon 18, such as through the one or more fluid delivery elements 58, where the coolant may expand to cool the balloon 18. The expanded coolant may then be transferred from the interior chamber 60 of the balloon 18 to a coolant recovery reservoir 64 and / or a scavenging system through a fluid return conduit. Further, as discussed in more detail below, the size of the balloon 18 when fully expanded may be selected by the user based on various factors, such as the patient's anatomy and the diameter of the pulmonary vein ostium, and may also be independent of the balloon's flow rate and the fluid pressure generated by delivering the coolant to the balloon 18.

[0059] The treatment device 12 also includes a handle 66 coupled to the proximal portion 24 of the elongated body. The handle 66 includes one or more steering or deflection components for manipulating the elongated body 20, one or more treatment elements 16, and / or additional components of the treatment device 12. In one embodiment, the handle 66 includes an actuator element or button 68 that is in direct mechanical communication with the proximal portion of the shaft 48. In one embodiment, the button 68 is a sliding mechanism that is longitudinally movable within or relative to the handle 66. In this embodiment, movement or actuation (e.g., longitudinal movement) of the button 68 exerts a direct force on the shaft 48 and causes the shaft 48 to also slide or move longitudinally within the elongated body 20. When the distal neck 56 of the balloon 18 is coupled to the distal portion 50 of the shaft 48, this longitudinal movement of the shaft 48 caused by the engagement of the button 68 will cause a change in the shape and / or size of the balloon 18, as discussed in more detail below. Further, the handle 66 is fixedly coupled to the elongated body proximal portion 24, while the button 68 is mechanically coupled to the shaft 48; however, in one embodiment, the button 68 and the shaft 48 are free to move relative to the handle 66 and the elongated body 20 (even though the button 68 may be at least partially disposed within the handle), thereby allowing the button 68 and the shaft 48 to move based on the balloon pressure without user actuation or control. That is, when the button 68 is not engaged by the user, in one embodiment, both the button 68 and the shaft 48 are free to move longitudinally relative to the handle 66 and the elongated body 20 based on the force exerted on the shaft distal portion 50 by the inflation pressure of the balloon 18. As described herein, the handle 66 also includes a connector that can be directly or indirectly mated with the control unit 14 to establish communication between one or more components of the treatment device 12 and one or more components of the control unit 14.

[0060] In one embodiment, the treatment device 12 and / or the control unit 14 include one or more sensors. In one non-limiting example, the treatment device 12 includes one or more pressure sensors 70 on and / or within the balloon 18. These pressure sensors 70 are configured to record pressure waves from or through the balloon 18, such as pressure waves generated by the beating heart of the patient. Fig.21 As shown, the size or value of the pressure wave recorded by the sensor 70 can be used to determine whether the balloon 18 completely blocks the blood vessel, such as the pulmonary vein orifice. Since the balloon 18 is used at low pressure (e.g., <6 psig), the patient's heartbeat can be accurately monitored using the pressure sensor 70. When the blood vessel is blocked, the pressure signal (i.e., the pressure wave generated by the heartbeat) becomes less obvious and is indirectly proportional to the blockage quality of the blood vessel. In a non-limiting example, a relatively flat signal can indicate appropriate blockage.

[0061] Additionally or alternatively, one or more sensors may be used to evaluate the expansion and / or configuration of the balloon 18. For example, in one embodiment, the control unit 14 includes a pressure sensor 72 that is fluidically connected to a Pitot tube 74 in the treatment device 12. The Pitot tube 74 may be made of polyimide or (one or more) similar materials and may have an outer diameter of approximately 0.030 inches. In one embodiment, the Pitot tube 74 includes a distal end 76 that is at least partially located within the internal chamber 60 of the balloon 18 and a proximal end 77 opposite the distal end 76, the proximal end 77 containing, coupled to, or otherwise connected to the pressure sensor 72. The distal end 76 of the Pitot tube includes an opening that is exposed to the fluid circulating in the internal chamber 60. The Pitot tube 74 is used to determine the dynamic pressure (P) of the fluid in the internal chamber 60 based on the dynamic pressure of the fluid in the internal chamber 60. 动态 ) and static pressure (P 静态 ) to measure the stagnation point (P 滞止 ) at the distal end 76, the pressure within the internal chamber 60 being the pressure near the opening at the distal end 76 (e.g., Figure 4 shown):

[0062] P 滞止 = P 静态 + P 动态 (1)

[0063] in:

[0064] P 动态 = (ρ* v 2 ) / twenty two)

[0065] As discussed in more detail below, the velocity of the fluid (e.g., coolant) circulating within the balloon 18 is relatively low, particularly near the opening at the distal end 76 of the pitot tube. Thus:

[0066] P 动态 = 0 (3)

[0067] as well as

[0068] P 滞止 = P 静态 (4)

[0069] Therefore, the Pitot tube 74 is at the stagnation point (P 滞止 The fluid pressure measured at ) can be used to directly determine the static pressure (P 静态 ) (i.e., balloon pressure). However, it will be appreciated that a pitot-static tube may be used in place of a pitot tube. Additionally or alternatively, other components may be used to determine pressure, such as piezoresistive MEMS, fiber optic systems based on the Fabry-Perot principle, capacitive resistors, thermistors, etc. Determining the pressure within the interior chamber 60 allows the user and / or control unit 14 to set the diameter of the balloon 18 based on the determined pressure, monitor the pressure of the balloon 18 to prevent over-pressurization, and / or monitor the thrust on the treatment device 12 or a portion thereof when in use.

[0070] In one embodiment, a coolant supply reservoir 62, a coolant recovery reservoir 64, and / or one or more alternative energy sources for supplying a selected treatment mode to the treatment element 16 (e.g., a radio frequency generator, an ultrasound generator, a light source, etc.) and various control mechanisms for the medical system 10 are contained in the control unit 14. For example, if a fluid other than a coolant is used to inflate the balloon 18, the control unit 14 may also include an inflation fluid reservoir. The control unit 14 also includes one or more computers 78 having one or more displays 80 and processing circuits 82 and / or software modules. The processing circuit 82 may be programmed or programmable to perform automated operations and performance of the features, sequences, or processes described herein. As a non-limiting example, the processing circuit 82 includes a memory and a processor, the memory communicates with the processor and has instructions that, when executed by the processor, configure the processor to perform one or more system functions. For example, the processing circuit 82 may be configured to receive electrical signals from pressure sensors 70, 72 to assess the occlusion of the balloon 18 on the blood vessel and / or determine the fluid flow rate and / or balloon pressure. It will be appreciated that one or more system components may be physically located external to the control unit 14; however, for simplicity, any system component not part of the treatment device 12 may be referred to herein as being located within the control unit 14. In one embodiment, the control unit 14 (e.g., the processing circuit 82) is configured to convert one or more determined pressure values ​​(e.g., P 滞止 and / or P 静态) is compared to a threshold pressure to determine whether balloon 18 is maintained at a pressure between 0.2 psig and 3.0 psig. Additionally or alternatively, control unit 14 is configured to determine the pressure value (e.g., P) during a procedure. 滞止 and / or P 静态 For example, the control unit 14 may be configured to compare the determined pressure values ​​recorded during the expansion phase with the determined pressure values ​​recorded during the ablation phase.

[0071] Now refer to Figure 5-20 , the expansion of balloon 18 will now be discussed in more detail. In one embodiment, balloon 18 is a highly compliant balloon that can be expanded to various outer diameters while maintaining a high degree of flexibility or compliance with the contours of an object (e.g., a tissue surface) in contact with balloon 18. For example, when balloon 18 is expanded to have a first configuration having at least a substantially circular shape, balloon 18 can be expanded to a first outer diameter OD1, such as approximately 23 mm (±2 mm) (e.g., approximately 15 mm). Figure 6 If desired, the balloon 18 can be further expanded to a larger second outer diameter OD2, such as about 36 mm (± 2 mm) (eg, Figure 7 As shown). Of course, the balloon 18 can be expanded to any outer diameter between the first outer diameter and the second outer diameter, depending on the surgical procedure, the patient's anatomy, the user's preference, etc. However, regardless of the outer diameter of the balloon 18, the balloon 18 remains highly compliant. A fluid, such as a coolant, used to inflate the balloon 18 can be delivered to the internal chamber 60 at a pressure between 0.2 psig and 3.0 psig. The medical system 10 may also include one or more flow control valves located in the fluid flow path of the medical system 10, and a vacuum pump or vacuum source 84 for removing fluid from the balloon's internal chamber 60. For example, the medical system 10 (e.g., the control unit 14) may include a flow control valve 86 in communication with the fluid delivery conduit 42 and a pressure control valve 88 in communication with the fluid return conduit 46 (e.g., as shown in FIG. 1 ). Figure 5 shown).

[0072] In one embodiment, the button 68 and shaft 48 are free to move relative to the handle 66 and the elongated body 20. When the balloon 18 is inflated, the shaft 48 is free to move and assumes its position based on the pressure differential between the two sides of the balloon 18. As the outer diameter of the balloon 18 increases with pressure, the length of the balloon 18 also increases because the movement of the shaft 48 (in this case, in the proximal to distal direction) is not constrained, as in currently known devices.

[0073] exist Figure 8A comparison of balloon diameter and inflation pressure between the balloon 18 of the present disclosure and two currently known balloon devices is shown in FIG. Curve 90 of the balloon 18 of the present disclosure shows that, even at low inflation pressures (e.g., up to 3.0 psig), inflation of the balloon results in a rapid increase in the balloon outer diameter. In contrast, curves 92, 94 of the currently known balloon devices show that, as inflation pressure increases, the balloon outer diameter increases much more slowly. Fig. 9 A graph is shown of tissue contacting surface area versus inflation pressure on balloon 18. In some embodiments, lower inflation pressures result in greater tissue contacting surface area.

[0074] Now refer to Figure 10-27 , the use of treatment device 12 is discussed in more detail. Fig.10 and 11 The distal surfaces of the currently known balloon 96 and the balloon 18 of the present disclosure are shown, respectively, for ablating an area of ​​target tissue. As described above, the balloon 18 of the present invention is highly compliant (i.e., the balloon 18 is "soft") even when inflated. Thus, pushing the balloon 18 against the target tissue area, even when gently pushed, causes the balloon 18 to deform so that a larger surface area of ​​the balloon 18 is in contact with the target tissue area. Fig.10 A front view (ie, distal side 98) of a currently known balloon 96 is shown, with an exemplary tissue contacting region 100 illustrated. Fig.11 A front view (ie, distal side 102 ) of a balloon 18 of the present disclosure is shown, with an exemplary tissue contacting region 104 illustrated. Fig.10 and 11 A comparison of the balloon 18 and the treatment device 12 shows that the high degree of compliance or softness of the balloon 18 results in a larger, more uniform tissue contact surface, which in turn results in more efficient lesion formation. When the balloon 18 is in the at least substantially circular first configuration, the treatment device 12 can be used in various surgical procedures, such as pulmonary vein isolation. Although the treatment device 12 is shown in the figures as having a shaft distal tip 52 that protrudes beyond the distal side 102 of the balloon 18, it will be understood that the treatment device 12 may alternatively have an atraumatic, substantially continuous distal side 102 without the shaft distal tip 52 protruding.

[0075] The same principle applies when the lateral surface of the balloon 18 is used to ablate an area of ​​target tissue. Fig.12 and 13 For example, Fig.12 A side view of a highly compliant balloon 18 is shown inflated when a lateral surface 106 of the balloon 18 contacts an area of ​​target tissue 108, and shows that when the balloon 18 is pushed against the area of ​​target tissue 108, the balloon flattens to create a larger, more uniform tissue contact area 104. Fig.131 and 2. A lateral surface 106 of the balloon 18 is shown in FIG. 2 with an exemplary tissue contacting region 104 thereon when the balloon 18 is in contact with a target tissue region.

[0076] Figure 11-13 The use of the balloon 18 is shown when the balloon is in a first configuration that is at least substantially circular. For example, the balloon 18 can be expanded into a spherical, oval, obovate, elliptical, or any other shape in which the necks of the proximal side 54 and the distal side 56 of the balloon 18 are located outside the interior chamber 60. Conversely, Figure 14-17 The balloon 18 is shown being used to ablate an area of ​​target tissue 108 using the lateral surface 106 of the balloon 18 when the balloon 18 is in a second, at least substantially annular, configuration. In this configuration, the balloon 18 may be positioned against the area of ​​target tissue 108 such that the tissue contact region 104 is located about the equator or outer periphery 110 of the balloon 18. When the balloon 18 is in the second, at least substantially annular configuration, the treatment device 12 may be used, for example, to ablate a rotor (a rotating area of ​​abnormal current flow) and / or to create a punctate lesion in an area of ​​target tissue.

[0077] In one embodiment, the balloon 18 is converted from the at least substantially circular first configuration to the at least substantially annular second configuration by engagement with or actuation of the button 68, which causes the shaft 48 within the elongated body 20 to move in a distal-to-proximal direction, thereby causing the proximal neck 54 and the distal neck 56 of the balloon 18 to flip into the interior chamber 60 (e.g., Figure 14-17 In embodiments where the fluid delivery element 58 is coupled to, positioned within, or otherwise associated with the shaft 48, retraction of the shaft 48 also directs the fluid delivery element 58 toward the equator 110 of the balloon 18 to focus the cooling effect of the coolant circulating within the interior chamber 60 toward the equator 110, thereby forming a lateral surface for effective tissue ablation. Conversely, as Fig.17 As shown in the tissue contact area 104 on the distal side 102 of the balloon 18, the distal side 98 of the balloon 18 may not be well adapted to the area of ​​the target tissue for ablation.

[0078] Figure 18-20 1 and 10. The lateral surface 106 of the balloon 18 is used to ablate a region of target tissue 108 when the balloon 18 is in the elongated third configuration. In one embodiment, the balloon 18 is initially in a delivery configuration in which the balloon 18 is not expanded (eg, Fig.18Once the area of ​​target tissue is approached, balloon 18 is only partially inflated or not inflated at all (i.e., to an inflation pressure below arterial pressure), and shaft 48 is extended from the initial position in a proximal-to-distal direction within elongated body 20 (e.g., by actuation of button 68 by the user) to cause balloon 18 to elongate and create a relatively large tissue contact area 104 when lateral surface 106 contacts an area of ​​target tissue 108 (e.g., as shown in FIG. 1 ). Fig.19 and 20 ). In this configuration, balloon 18 can be used to create a linear, at least substantially linear, or elongated lesion (e.g., when forming a mitral isthmus isolation line). Because the circulation (flow rate) of the coolant within interior chamber 60 can be controlled independently of the inflation pressure (via the flow volume of the delivery and return conduits and / or the strength of the vacuum source), balloon 18 can be used to ablate an area of ​​target tissue even in the most deflated or partially inflated state.

[0079] The treatment device 12 disclosed herein with a highly compliant balloon 18 can also be used to safely occlude a vessel, such as when performing pulmonary vein isolation, without causing the distal end of the treatment device 12 (e.g., the shaft distal tip 52 and the distal portion of the balloon 18) to advance too far into the vessel. The deeper the balloon is advanced into the vessel, the greater the risk of tamponade, aneurysm, and / or nerve damage. Figure 22-24 A treatment device 12 is shown having a highly compliant balloon 18 for occluding a blood vessel 111, and Fig.25 A treatment device 112 is shown having a balloon 96 for occluding a blood vessel 111 . Fig.26 A graph comparing the depth to which the distal ends of balloons 18, 96 can travel into a blood vessel 111 according to force is shown, wherein lines 114, 116, 118 and 120 represent Figure 22-25 Scenario. Current wisdom in the art is that a compliant balloon inflated at low pressure during an occlusion will tend to travel too far in the vessel. However, the treatment device 12 of the present disclosure does not have this problem. Because the shaft 48 is free to move when the user is not pressing the button 68, the axial force provided by the user on the handle 66 during an occlusion is not transferred or is only transferred to a small extent to the shaft 48 (and the distal end 52 of the shaft). Instead, the axial force provided by the user at the handle 66 will be transmitted through the slender body 20 and therefore to the rear of the balloon 18. This causes the balloon diameter to increase and thus prevents the balloon 18 from entering the blood vessel 111 to an unacceptable or unsafe depth.

[0080] This phenomenon can be likened to passing a rope through a hole: it may be difficult to push the rope through the hole, but it is very easy to pull the rope through the hole. Fig. 22A first method of occluding a vessel 111 with a highly compliant balloon 18 is shown, wherein the axial force provided by the user is transmitted only through the shaft 48 (similar to pulling a "rope" through a "hole"), as depicted by the arrows. For example, the balloon 18 is inflated to an outer diameter of 28 mm at 1.0 psig. Fig.23 A second method of occluding a blood vessel 111 with a highly compliant balloon 18 is shown, wherein an axial force provided by a user is transmitted through the shaft 48 (similar to pulling a "rope" through a "hole"), and through the elongated body 20 (similar to pushing a "rope" through a "hole"), as depicted by the arrows. For example, the balloon 18 is inflated to an outer diameter of 28 mm at 1.0 psig. Fig.24 A third method of occluding a blood vessel 111 with a highly compliant balloon 18 is shown, wherein the axial force provided by the user is transmitted only through the elongated body 20 (similar to pushing a "rope" through a "hole"), as depicted by the arrows. For example, the balloon 18 is inflated to an outer diameter of 28 mm at 1.0 psig. Finally, Fig.25 A method of occluding a blood vessel 111 with a currently known (i.e., non-highly compliant) balloon 96 is shown, wherein the axial force provided by the user is transmitted through the elongated body 28 and / or the shaft 122. As the balloon 96 is more rigidly inflated, transmitting the axial force through the elongated body 28 relative to the shaft 122 can have the same or approximately the same effect on the balloon 96. Thus, Fig.25 Arrows are shown in , to depict the axial force transmitted to the elongated body 28 and / or shaft 122. For example, the balloon 96 is inflated to an outer diameter of 28 mm at a pressure of 18 psig.

[0081] If available from Figure 22-25 and Fig.26 As seen in the accompanying diagrams, transferring the axial force generated by the user on the handle 66 to the shaft 48 can effectively "pull" the highly compliant balloon 18 into the vessel 111 through the proximal-to-distal movement of the shaft 48 (which elongates and reduces the outer diameter of the balloon 18, thereby making it easier for the balloon 18 to advance into the vessel). However, transferring the axial force generated by the user on the handle 66 to the slender body 20, such as by disengaging the shaft 48 from the button 68 (e.g., to allow the shaft 48 to move freely relative to the handle 66 and the slender body 20), causes the slender body 20 to push against the rear of the balloon 18, resulting in an increase in the outer diameter of the balloon 18. This increase in outer diameter prevents the balloon 18 from advancing to an undesirable depth in the vessel 111. Further, Fig.24 The illustrated occlusion of a blood vessel by the highly compliant balloon 18 provides nearly identical results to occlusion of a blood vessel by the currently known non-highly compliant balloon 96. Thus, the user retains the benefits discussed herein of performing medical procedures using the highly compliant balloon 18 without the potential for patient injury currently anticipated when using a balloon inflated to a low pressure.

[0082] Now refer to Fig. 27 , an exemplary method of using a medical system 10 that includes a treatment device 12 having a highly compliant balloon 18 is shown. In an exemplary first step 130, a user navigates the treatment device 12 to a position proximate to an area of ​​target tissue 108. In one embodiment, the area of ​​target tissue 108 may be a pulmonary vein ostium, a location on the left atrium wall, or any other suitable location within the patient's body. The control unit 14 (e.g., processing circuitry 82) is then used to automatically, semi-automatically, and / or manually control the inflation and use of the balloon 18 to perform an ablation procedure. For example, in an exemplary second step 132, the user uses the touch screen display 80 and / or other user input device of the medical system 10 to select a desired size and / or outer diameter of the balloon 18. Then, the inflation phase begins, and the control unit 14 manipulates or otherwise controls the flow control valve 86 in the fluid delivery conduit 42, the pressure control valve 88 in the fluid return conduit 46, and / or other valves in the fluid flow path of the medical system 10 to provide a continuous flow of fluid to and from the balloon 18, thereby inflating the balloon 18 to a desired size and / or outer diameter (e.g., to an outer diameter selected by a user). In one embodiment, when the treatment device 12 is in communication with the control unit 14, the control unit 14 manipulates the flow control valve 86 to regulate or control the flow, delivery, and circulation of coolant to and within the balloon 18, and the control unit 14 manipulates the pressure control valve 88 to control the inflation pressure in the balloon 18 as measured by the pitot tube 74 (or other pressure sensor) in the balloon 18. Optionally, if a currently known treatment device is in communication with the control unit 14, the control unit 14 may be configured to provide a flow control valve 86 based on the PT5 ( Figure 514. The user may also manipulate the button 68 in the handle 66 to move the shaft 48 and adjust the shape and configuration of the balloon 18 during the inflation phase. For example, the shaft 48 may be advanced in a proximal-to-distal direction to extend the balloon 18 (thereby creating a linear lesion), or the shaft 48 may be retracted in a distal-to-proximal direction to convert the balloon 18 into an at least substantially annular shape (e.g., forming a punctate lesion or an ablation rotor). However, it will be understood that the user may alternatively not engage the button 68 and may alternatively allow the shaft 48 to move freely within the elongated body 20 during the inflation phase (e.g., when performing a pulmonary vein isolation procedure). In one embodiment, the balloon 18 is in fluid communication with a vacuum pump or vacuum source 84 and is inflated at a constant inflation pressure between 0.2 psig and 3.0 psig. In one embodiment, the balloon 18 is inflated using a coolant delivered to the interior chamber 60 at a flow rate of approximately 1500 sccm (±500 sccm). For example, the coolant flow rate may be adjusted to 1500 sccm (±500 sccm) using the flow control valve 86, and the pressure of the balloon 18 may be set between 0.2 psig and 3.0 psig by adjusting the pressure control valve 88. Alternatively, a fixed amount of coolant may be delivered to the balloon 18 to increase the pressure within the balloon 18 to a target or desired pressure, for example, through automatic, semi-automatic, or manual manipulation of the flow control valve 86, and the pressure control valve 88 may be manipulated (e.g., automatically or semi-automatically by the control unit 14, or manually by a user) to help maintain or stabilize the pressure within the balloon at the target pressure. In one embodiment, once the target balloon pressure is reached, the control valves 86 , 88 may be closed (eg, automatically or semi-automatically by the control unit 14 , or manually by a user) to stop the flow of coolant to and from the balloon 18 .

[0083] In an exemplary fourth step 136, once the balloon 18 is inflated and in the desired configuration, the control unit 14 automatically or semi-automatically begins the ablation phase and adjusts the control valves 86, 88 (and / or the user can manually adjust the control valves 86, 88) to maintain the balloon 18 at a relatively low ablation pressure. In one embodiment, the control unit 14 determines that the balloon 18 has reached the desired expanded size based on the pressure measurements from the pressure sensors 70, 72, and automatically begins the ablation phase. In another embodiment, the control unit 14 determines that the balloon 18 has reached the desired expanded size based on the pressure measurements from the pressure sensors 70, 72, and prompts the user to confirm and manually start the ablation phase. Once the ablation phase is initiated, no further adjustments to the size, shape, and / or configuration of the balloon 18 are allowed. In one embodiment, the control unit 14 (e.g., the processing circuit 82) includes software with which the user can interact to lock or prevent further modifications to the balloon size, shape, and / or configuration.

[0084] In an exemplary fifth step 138, the user may position the treatment device 12 so that the balloon 18 is in contact with the target tissue area. In one embodiment, the balloon 18 is used to ablate tissue at a constant pressure between 0.2 psig and 3.0 psig, which is the same pressure as the inflation pressure, as opposed to the inflation pressure of approximately 17.5 psig required in currently known devices. This relatively low pressure allows the balloon 18 to be highly compliant and very flexible during use. In one embodiment, the balloon 18 is used to perform pulmonary vein isolation, and an axial force applied by the user on the handle 66 to enhance contact tissue contact with the balloon 18 and occlusion by the balloon 18 is transmitted through the elongated body 20. In turn, this applies an axial force on the rear of the balloon 18 and increases the outer diameter of the balloon, which prevents the balloon 18 from traveling too deep in the pulmonary veins. Although positioning the balloon 18 in contact with the area of ​​the target tissue is described as the fifth step 138, it will be understood that this step may be performed before, during, or after the inflation stage.

[0085] Further, in an exemplary sixth step 140, the control unit 14 may continuously monitor pressure measurements from the pressure sensors 70, 72 during the inflation phase and the ablation phase in a feedback loop to ensure that the balloon 18 remains at a predetermined size, shape, and / or configuration so that the balloon 18 does not become over-pressurized, and / or monitor the thrust applied to the handle 66 and / or the elongated body 20 during use. If the control unit 14 determines that the coolant flow and / or balloon pressure needs to be adjusted (e.g., based on the user's initial balloon size specification), the control unit 14 automatically adjusts the control valves 86, 88, the vacuum pump or vacuum source 84, and / or other system components 10 to return the pressure of the balloon 18 to within the range of 0.2 psig to 3.0 psig. Alternatively, if the pressure measurements indicate a system and / or balloon failure, the control unit 14 and / or the user may interrupt the delivery of coolant to the balloon 18. When the balloon is inflated and used to ablate a target tissue area, the balloon 18 is connected to the vacuum pump or vacuum source 84 (that is, when the balloon 18 is in a vacuum state), and the flow rate of the coolant used to cool the balloon 18 and the balloon pressure can be independently controlled by the control unit 14. In other words, regardless of the coolant flow rate within the balloon 18, the control unit 14 can maintain the balloon at a pressure between 0.2 psig and 3.0 psig. However, the flow rate is adjustable. For example, when the balloon 18 is in the elongated third configuration (such as Figure 18-20 ), with the balloon 18 in an expanded configuration (e.g., Figure 10-17 In one embodiment, the flow rate may be automatically or semi-automatically adjusted or determined by the control unit 14 based on the selected inflation pressure of the balloon 18. Although monitoring pressure measurements is described as a sixth step 140, it will be understood that this step may be performed at any time during the procedure, in discrete steps, or continuously throughout the procedure (e.g., as shown in FIG. 1 ). Fig. 27 shown).

[0086] In an exemplary seventh step 142, the deflation phase begins (e.g., the flow of coolant is interrupted or reduced), and the balloon 18 is converted to a delivery configuration for safe removal from the patient. Optionally, the balloon 18 may be allowed to thaw before removal to prevent injury when removing a balloon that is cryoadhered to the target tissue area.

[0087] It will be appreciated by those skilled in the art that the present invention is not limited to what has been specifically shown and described above. Furthermore, unless otherwise mentioned above, it should be noted that all drawings are not to scale. Based on the above teachings, various modifications and variations are possible without departing from the scope and spirit of the present invention.

[0088] It should be understood that the various aspects disclosed herein may be combined in combinations different from those specifically presented in the specification and drawings. It should also be understood that, according to examples, certain actions or events of any process or method described herein may be performed in a different order, may be added, combined, or omitted entirely (e.g., all described actions or events may not be necessary to perform the technology). In addition, although for clarity, certain aspects of the present disclosure are described as being performed by a single module or unit, it should be understood that the technology of the present disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0089] It will be appreciated by those skilled in the art that the present invention is not limited to what has been specifically shown and described above. Furthermore, unless otherwise mentioned above, it should be noted that all drawings are not to scale. Based on the above teachings, various modifications and variations are possible without departing from the scope and spirit of the present invention.

Claims

1. A system for ablating tissue, the system comprising: A therapeutic device, comprising: Highly compliant balloon; an elongated body having a proximal portion, a distal portion, a central lumen, a guidewire lumen, a pitot tube, a pressure sensor and an outer wall, the central lumen having an inner diameter and an outer diameter, the inner diameter being defined by the guidewire lumen, the outer diameter being circular and defined by the outer wall, the central lumen defining a fluid return conduit disposed between the guidewire lumen and the outer wall, and the pitot tube being disposed in the fluid return conduit; a shaft slidably disposed within the elongated body; a handle fixedly coupled to the proximal portion of the elongated body; and a button in mechanical communication with the shaft, the button being movable to a first position in which the button is depressed and a second position in which the button is relaxed, wherein movement of the button to the first position applies a force on the shaft and movement of the button to the second position releases the force on the shaft, allowing the shaft to move freely relative to the handle and the elongated body and allowing the highly compliant balloon to expand; A control unit includes a fluid supply reservoir connected to the highly compliant balloon fluid and a pressure sensor connected to the pitot tube fluid, the control unit being configured to deliver fluid from the fluid supply reservoir to the highly compliant balloon to maintain the highly compliant balloon at a balloon pressure between 0.2 psig and 3.0 psig.

2. The system according to claim 1, characterized in that The control unit is configured to maintain the balloon pressure between 0.2 psig and 3.0 psig during inflation of the highly compliant balloon.

3. The system according to any one of claims 1 or 2, characterized in that The control unit is configured to maintain the balloon pressure between 0.2 psig and 3.0 psig during tissue ablation.

4. The system according to any one of claims 1 or 2, characterized in that Also includes: Vacuum source; as well as a fluid delivery conduit between the fluid supply reservoir and the highly compliant balloon; Wherein, the fluid return conduit is between the highly compliant balloon and the vacuum source.

5. The system according to claim 4, characterized in that Also includes: a flow control valve in fluid communication with the fluid delivery conduit; as well as a pressure control valve in fluid communication with the fluid return conduit, The control unit is configured to selectively adjust the flow control valve and the pressure control valve to maintain the balloon pressure between 0.2 psig and 3.0 psig.

6. The system according to any one of claims 1 or 2, characterized in that: in: The Pitot tube is at least partially disposed within the highly compliant balloon.

7. The system according to claim 6, characterized in that The control unit is configured to determine the balloon pressure based on pressure measurements recorded by the pressure sensor.

8. The system according to claim 1, characterized in that The control unit is configured to determine a static pressure within the highly compliant balloon based on the recorded stagnation pressure within the highly compliant balloon.

9. The system according to claim 1, characterized in that The treatment device also includes a pressure sensor within the highly compliant balloon, which is connected to the control unit and is configured to record a pressure signal generated by a heartbeat. The control unit is configured to determine the occlusion state of the highly compliant balloon based on the pressure signal recorded by the pressure sensor.

10. The system according to claim 1, wherein: The shaft has a proximal portion and a distal portion, and the highly compliant balloon has: a proximal neck coupled to the distal portion of the elongated body; as well as a distal neck coupled to the distal portion of the shaft, Retraction of the button from the initial position transitions the highly compliant balloon between a first configuration and a second configuration, and extension of the button from the initial position transitions the highly compliant balloon between the first configuration and a third configuration.

11. The system according to claim 10, characterized in that The first configuration is a substantially circular configuration.

12. The system according to claim 11, characterized in that The highly compliant balloon is expandable to a first outer diameter when in the first configuration and is further expandable to a second outer diameter when in the first configuration.

13. The system of claim 12, wherein: The first outer diameter is 23 mm, and the second outer diameter is 36 mm.

14. The system of claim 13, wherein: The second configuration is at least one of the group consisting of an annular configuration and an elongated configuration.

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