Thermal balloon angioplasty system providing diagnostic and treatment based on real-time feedback of therapeutic effect

Abstract

A medical system (100) and method of use are disclosed. The system (100) includes: an inflatable balloon (102) adapted to be deployed in a blood vessel (205) lumen; a pressure source adapted to inflate and deflate the balloon (102); a heating element disposed in the balloon (102) and adapted to provide heat to the blood vessel (205) lumen; a sensing device disposed in the balloon (102); a processor (153); and a tangible, non-transitory computer readable medium that stores instructions. When executed by the processor (153), the instructions cause the processor (153) to: based on data received from the sensing device, generate cross-sectional data of the balloon (102) and / or blood vessel (205) where the balloon (102) is deployed. The system (100) also includes a display (140) adapted to show the cross-sectional data of the balloon (102) and the blood vessel (205).

Description

THERMAL BALLOON ANGIOPLASTY SYSTEM PROVIDING DIAGNOSTIC AND TREATMENT BASED ON REAL-TIME FEEDBACK OF THERAPEUTIC EFFECTBACKGROUND

[0001] Angioplasty is ubiquitous in many medical treatments today and involves deploying a balloon in an artery or vein that is diseased, and inflating the balloon. In one common application, angioplasty is a procedure used to open blocked arteries, such as blocked coronary arteries caused by coronary artery disease. The deployed balloon may be used restore blood flow to the heart muscle without open-heart surgery, and allows for components, such as stents, to be deployed after the artery is open.

[0002] Thermal angioplasty involves applying heat via the deployed balloon and potentially improves standard percutaneous transluminal angioplasty (PTA) when applied for a short duration (e.g., less than approximately 15 s) and in temperature ranges (e.g., less than approximately 70°C) that modify tissue properties without inducing thermal ablation. Thermal angioplasty may be useful in attempting to expand a vein affected by post thrombotic syndrome (PTS) that can develop from long-term effects from a previous deep venous thrombosis (DVT). These conditions can result in scarring of the tissue of the vein, resulting in a reduced cross- sectional area (CSA) or complete occlusion.

[0003] Thermal angioplasty can be carried out at lower dilatation pressures by the balloon using short duration heating because the vessel wall softens in response to the heat, thereby potentially limiting vascular damage that can occur using high pressure balloon dilatation. Short-term thermal dilatation is associated with (i) reversible collagen thermal denaturation and stretchfixing of elastin, (ii) collagen fiber re-orientation in the circumferential direction, and (iii) stretching of the smooth muscle cells (SMCs). These effects allow the expansion of the vessel at a comparatively lower pressure, reducing vascular damage, which can result in restenosis after balloon angioplasty due to over-proliferation of the SMCs in response to the injury. Similarly, reducing vascular trauma of balloon dilatation (venop lasty) in a deep venous application may reduce the risk of re-thrombosis; therefore, offering a more durable treatment solution for vessels that otherwise cannot be stented. To date, a practical implementation of this treatment has not emerged. One challenge with this approach is the inability to treat the tissue within a therapeutic window without under-treating or over-applying the thermal treatment and causing thermalinjury. As a result, the clinician / user cannot properly apply heat to the diseased vascular portion and for the correct amount of time not only to treat the diseased vascular portion properly, but also to terminate treatment before damage to the vascular portion occurs.

[0004] What is needed, therefore, is a system and method for thermal angioplasty that overcomes at least the noted drawbacks of the known approaches described above.SUMMARY

[0005] In accordance with a representative embodiment, a medical system comprises: an inflatable balloon adapted to be deployed in a blood vessel lumen; a pressure source adapted to inflate and deflate the balloon; a heating element disposed in the balloon and adapted to provide heat to the blood vessel lumen; a sensing device disposed in the balloon; a processor; and a tangible, non-transitory computer readable medium that stores instructions. When executed by the processor, the instructions cause the processor to: based on data received from the sensing device, generate cross-sectional data of the balloon and / or blood vessel where the balloon is deployed; and a display adapted to show the cross-sectional data of the balloon and the blood vessel.

[0006] In accordance with another representative embodiment, a method of monitoring a medical procedure is described. The method comprises: providing heat during balloon pressurization to expand a blood vessel lumen; generating cross-sectional data of the balloon and / or blood vessel where the balloon is deployed; displaying the cross-sectional data of the balloon and / or blood vessel; providing an input to a graphic user interface (GUI); and changing the heat provided to the balloon, or changing the pressure applied to the balloon, or both via an input on the GUI.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The example embodiments are best understood from the following detailed description when read with the accompanying drawing figures. It is emphasized that the various features are not necessarily drawn to scale. In fact, the dimensions may be arbitrarily increased or decreased for clarity of discussion. Wherever applicable and practical, like reference numerals refer to like elements.

[0008] Fig. 1 A is a simplified block diagram of a system for thermal balloon angioplasty, inaccordance with a representative embodiment.

[0009] Fig. IB is a simplified block diagram of the console of the system of Fig. 1A comprising a graphical user interface (GUI) in accordance with a representative embodiment.

[0010] Fig. 2 illustrates a display comprising a GUI used in a system for thermal balloon angioplasty in accordance with a representative embodiment.

[0011] Fig. 3 A is a simplified block diagram of a system for thermal balloon angioplasty, in accordance with a representative embodiment.

[0012] Fig. 3B is a simplified block diagram of a system for thermal balloon angioplasty, in accordance with a representative embodiment.

[0013] Fig. 4 is a simplified block diagram of a system for thermal balloon angioplasty, in accordance with a representative embodiment.

[0014] Fig. 5 is a simplified block diagram of a system for thermal balloon angioplasty, in accordance with a representative embodiment.

[0015] Fig. 6 is a simplified block diagram of a system for thermal balloon angioplasty, in accordance with a representative embodiment.

[0016] Fig. 7 is a graph of impedance versus tissue pressure adapted for display on a display of a system for thermal balloon angioplasty in accordance with a representative embodiment.DETAILED DESCRIPTION

[0017] In the following detailed description, for the purposes of explanation and not limitation, representative embodiments disclosing specific details are set forth in order to provide a thorough understanding of embodiments according to the present teachings. However, other embodiments consistent with the present disclosure that depart from specific details disclosed herein remain within the scope of the appended claims. Descriptions of known systems, devices, materials, methods of operation and methods of manufacture may be omitted so as to avoid obscuring the description of the representative embodiments. Nonetheless, systems, devices, materials and methods that are within the purview of one of ordinary skill in the art are within the scope of the present teachings and may be used in accordance with the representative embodiments. It is to be understood that the terminology used herein is for purposes of describing particular embodiments only and is not intended to be limiting. Definitions and explanations for terms herein are in addition to the technical and scientific meanings of the termsas commonly understood and accepted in the technical field of the present teachings.

[0018] It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements or components, these elements or components should not be limited by these terms. These terms are only used to distinguish one element or component from another element or component. Thus, a first element or component discussed below could be termed a second element or component without departing from the teachings of the inventive concept.

[0019] As used in the specification and appended claims, the singular forms of terms ‘a’, ‘an’ and ‘the’ are intended to include both singular and plural forms, unless the context clearly dictates otherwise. Additionally, the terms “comprises,” and / or “comprising,” and / or similar terms when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0020] Unless otherwise noted, when an element or component is said to be “connected to”, “coupled to”, or “adjacent to” another element or component, it will be understood that the element or component can be directly connected or coupled to the other element or component, or intervening elements or components may be present. That is, these and similar terms encompass cases where one or more intermediate elements or components may be employed to connect two elements or components. However, when an element or component is said to be “directly connected” or “immediately adjacent” to another element or component, this encompasses only cases where the two elements or components are connected or disposed immediately adjacent to each other without any intermediate or intervening elements or components.

[0021] As described herein in connection with various representative embodiments, a system and method for monitoring a medical procedure is described enabling effective treatment of lesions either on the arterial or venous side. As described more fully below, the systems and methods of the present teachings enable monitoring of a thermal angioplasty treatment so that in-situ and real-time changes to the treatment can be effected. Just by way of illustration, determining the cross-sectional area and compliance of the vein or artery enables monitoring of the vein or artery during a thermal angioplasty. This enables, for example, changes to be made to increase heat applied in the balloon to continue treatment, as well as to terminate treatment to avoid damagingthe vein or artery by over-heating.

[0022] By the present teachings, deployment of angioplasty balloons in thermal angioplasty procedures results in improvements in the field of non-invasive discovery / monitoring and monitored treatment of diseased veins and arteries. More generally, as will become clearer as the present description continues, the present teachings foster improvement to the deployment and use of catheters comprising angioplasty balloons in medical applications, resulting in improvements in minimally-invasive medical technologies. Finally, it is noted that the systems and methods of gathering real-time data (including image data), determining various characteristics based on these data in real-time, and taking appropriate action in real-time cannot practically be performed in the mind, but rather require hardware (e.g., a processor) and computer-executable instructions (“instructions”) stored on tangible, non-transitory computer readable media of as described in connection various representative embodiments, to realize the real-time monitoring, diagnosis and treatment of diseased veins or arteries.

[0023] It is noted that while representative embodiments focus on applications of the present teachings to diagnosis and treatment of diseased veins (e.g., post-thrombotic lesions in deep venous disease, or below the knee arterial lesions associated with critical limb ischemia), this is merely illustrative. More generally, the systems and methods of the representative embodiments may be used in the diagnosis and treatment of diseased arteries (e.g., coronary arteries).

[0024] Fig. 1A illustrates a system 100 is a simplified block diagram of a system for thermal balloon angioplasty in accordance with a representative embodiment.

[0025] The system 100 comprises a balloon catheter device 101 comprising a balloon catheter (not shown in Fig. 1) and an imaging device (not shown in Fig. 1) adapted to expand and apply heat to a blood vessel.

[0026] The system further comprises a controller 150 and a console 180. As described more fully below, the balloon catheter device 101 comprises a multi-lumen catheter allowing for fluid transport, guidewire path, and housing electrical leads connecting the energy source to the distal end of the catheter. The balloon catheter device 101 also comprises an inflatable balloon element adapted to achieve clinically relevant pressures and maintaining integrity within the temperature ranges as required to achieve clinical effectiveness. The balloon catheter device 101 also comprises a heating element disposed inside, or in one embodiment, outside the balloon. These heating elements comprise, for example, a thermistor, radio frequency (RF) or otherelectromagnetic heating element, a laser heating element, or an ultrasound element. The balloon catheter device 101 further comprises a temperature sensor located within the balloon or in other embodiments, outside the balloon, and one or more known sensing / imaging elements disposed inside the balloon and designed to detect / image vascular changes, as well as provide real-time monitoring of the balloon catheter device 101 and the vessel in which the balloon catheter device 101 is deployed. Just by way of illustration, known imaging modalities contemplated to be deployed in the balloon catheter device 101 include, but are not limited to an Intravascular ultrasound (IVUS) imaging device, an optical coherence tomography (OCT) imaging device, a dielectric sensing / imaging device.

[0027] The controller comprises a processor 153, and is connected to the balloon catheter device 101 via a patient interface module (PIM) 108 or other standardized interface module used in medical applications. The controller 150 also comprises a memory 151 that store computerexecutable instructions (code) and medical data. Notably, the use of separate memories is merely illustrative, and fewer or more memories are contemplated. In accordance with representative embodiments described more fully below, these instructions, when executed by the processor 153 carry out various functions of representative embodiments described herein. As such, the memory 151 may store a set of software instructions that can be executed to cause the system 100 to perform some or all aspects of the methods or computer-based functions disclosed herein.

[0028] The controller 150 may be implemented by a computer that includes more elements than the controller 150 in Fig. 1. Notably, in accordance with a representative embodiment, the controller 150 is remote to the system 100, and is adapted to control various aspects of the system 100 remotely via connections including both wired and wireless connections and protocols. In this sense, the controller 150, at least in part is a specialty or particular computer useful in controlling the system 100.

[0029] In accordance with a representative embodiment, in addition to the PIM 106, other interfaces such as ports, disk drives, wireless antennas, or other types of receiver circuitry that connect the controller 150 to other electronic elements. Moreover, other interfaces such as buttons, keys, a mouse, a microphone, a speaker, a display, icons of a GUI on a display, or other elements that users can use to interact with the controller 150 such as to enter instructions and receive output.

[0030] The controller 150 may operate as a standalone device or may be connected, for example, using a network to other computer systems or peripheral devices. In representative embodiments, the system 100 performs logical processing based on digital signals received via an analog-to- digital converter. The controller 150 can also be implemented as or incorporated into various devices, such as a workstation that includes a controller, a stationary computer, a mobile computer, a personal computer (PC), a laptop computer, a tablet computer, or any other machine capable of executing a set of software instructions (sequential or otherwise) that specify actions to be taken by that machine. The controller 150 can be incorporated as or in a device that in turn is in an integrated system that includes additional devices. In an embodiment, the controller 150 can be implemented in a device that also provides video or data communication. Moreover, the controller 150 may be connected to components of the system via a local wired interface such as an Ethernet cable or via a local wireless interface such as a Wi-Fi connection.

[0031] The processor 153 may be considered a representative example of a processor of the controller 150 and executes instructions to implement some or all aspects of methods and processes described herein. The processor 153 is tangible and non-transitory. As used herein, the term “non-transitory” is to be interpreted not as an eternal characteristic of a state, but as a characteristic of a state that will last for a period. The term “non-transitory” specifically disavows fleeting characteristics such as characteristics of a carrier wave or signal or other forms that exist only transitorily in any place at any time. The processor 153 is an article of manufacture and / or a machine component. The processor 153 is configured to execute software instructions to perform functions as described in the various embodiments herein. The processor 153 may be a general-purpose processor or may be part of an application specific integrated circuit (ASIC). The processor 153 may also be a microprocessor, a microcomputer, a processor chip, a controller, a microcontroller, a digital signal processor (DSP), a state machine, or a programmable logic device. The processor 153 may also be a logical circuit, including a programmable gate array (PGA), such as a field programmable gate array (FPGA), or another type of circuit that includes discrete gate and / or transistor logic. The processor 153 may be a central processing unit (CPU), a graphics processing unit (GPU), or both. Additionally, any processor described herein may include multiple processors, parallel processors, or both. Multiple processors may be included in, or coupled to, a single device or multiple devices.

[0032] The term “processor” as used herein encompasses an electronic component able toexecute a program or machine executable instruction. References to a processor should be interpreted to include more than one processor or processing core, as in a multi-core processor. A processor may also refer to a collection of processors within a single computer system or distributed among multiple computer systems.

[0001] The memory 151 and may include a main memory and / or a static memory, where memories in the system 100 communicate with each other and the processor 153 via a bus. The memory 151 may be considered a representative example of a memory of the controller 150, and store instructions used to implement some or all aspects of methods and processes described herein. Memories described herein are tangible storage mediums for storing data and executable software instructions and are non-transitory during the time software instructions are stored therein. As used herein, the term “non-transitory” is to be interpreted not as an eternal characteristic of a state, but as a characteristic of a state that will last for a period. The term “non- transitory” specifically disavows fleeting characteristics such as characteristics of a carrier wave or signal or other forms that exist only transitorily in any place at any time. The memory 151 is an article of manufacture and / or machine components. The memory 151 is a computer-readable medium from which data and executable software instructions can be read by a computer (e.g., by the processor 153 of the controller 150). The memory 151 may be implemented as one or more of random access memory (RAM), read only memory (ROM), flash memory, electrically programmable read only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, a hard disk, a removable disk, tape, compact disk read only memory (CD-ROM), digital versatile disk (DVD), floppy disk, blu-ray disk, or any other form of storage medium known in the art. The memory may be volatile or non-volatile, secure and / or encrypted, unsecure and / or unencrypted. The inventive concepts also encompass a computer readable medium that stores instructions that cause a data processing system (such as the DSP of an NV A) to execute the methods described herein. Finally, a computer readable medium is defined herein to be any medium that constitutes patentable subject matter under 35 U.S.C. §101 and excludes any medium that does not constitute patentable subject matter under 35 U.S.C.§101. Examples of such media include non-transitory media such as computer memory devices that store information in a format that is readable by a computer or data processing system. More specific examples of non-transitory media include computer disks and non-volatile memories.

[0033] Additionally, the memory 151 is an example of a computer-readable storage medium. Computer memory is any memory which is directly accessible to a processor. Examples of computer memory include, but are not limited to RAM memory, registers, and register files. References to “memory” should be interpreted as possibly being multiple memories. The memory may for instance be multiple memories within the same computer system. The memory may also be multiple memories distributed amongst multiple computer systems or computing devices. Software instructions, when executed by the processor 153, perform one or more steps of the methods and processes as described herein. In an embodiment, the software instructions may reside all or in part within the memory 151 and / or the processor 153 during execution by the controller 150.

[0034] The console 180 is local to the controller 150. As described more fully below, the console 180 comprises a GUI and is connected to the controller 150 via a local wired interface such as an Ethernet cable or via a local wireless interface such as a Wi-Fi connection. As described more fully below, the console 180 may comprise a display, and through the GUI enables a user (e.g., a clinician / user) to provide inputs via the controller 150 to the balloon catheter device 101. Moreover, the console 180 be interfaced with other user input devices by which users can input instructions, including mouses, keyboards, thumbwheels and so on. The display of the console 180 may be a monitor such as a computer monitor, a display on a mobile device, an augmented reality display, a television, an electronic whiteboard, or another screen configured to display electronic imagery. The console 180 may also include one or more input interface(s) such as those noted above that may connect to other elements or components, as well as an interactive touch screen configured to display prompts to users and collect touch input from users. These interface may also be icons (not shown in Fig. IB) on the display 140 via the GUI 142.

[0035] The controller 150 may perform some of the operations described herein directly and may implement other operations described herein indirectly. For example, the controller 150 may indirectly control operations such as by generating and transmitting content to be displayed on the display 140. The controller 150 may directly control other operations such as logical operations performed by the processor 153 executing instructions from the memory 151 based on input received from electronic elements and / or users via the interfaces. Accordingly, the processes implemented by the controller 150 when the processor 153 executes instructions from the memory 151 may include steps not directly performed by the controller 150.

[0036] A method of monitoring a procedure using the balloon catheter device 101 according to the present teachings may include setting the pressure applied to the balloon of the balloon catheter device 101, and setting the heat applied via the balloon catheter device 101. The method further comprises receiving images from the selected imaging device disposed in the balloon catheter device 101. As described more fully herein, the method further comprises calculating the cross-sectional area (CSA) of the deployed balloon, and calculating the compliance of the vessel under examination. These parameters may then be displayed on the display of the console 180 and provide the user (clinician) with information that allows the clinician / user to alter or terminate the operation of the balloon catheter device 101. Just by way of example, and as described more fully below, when the CSA or compliance of the vessel reaches a plateau, the user, via inputs to the console (e.g., via the GUI) can increase the heat applied to the vessel to further expand the balloon and thus the diseased vein or artery. Moreover, the user may alter the applied pressure of the balloon via a similar input. Still further, based on the determined compliance, CSA and / or temperature in the balloon catheter device 101, the user may terminate the application of heat to avoid cauterizing or otherwise damaging the vessel. In yet another representative embodiments, threshold values of temperature and / or pressure may be stored in memory 151 and the controller can terminate a treatment automatically when a threshold is reached.

[0037] Fig. IB is a simplified block diagram of the console 180, PIM 106 of the system 100 of Fig. 1 A comprising a graphical user interface (GUI) in accordance with a representative embodiment. Various aspects and details of the currently described representative embodiments are common to the various representative embodiments described above in connection with Fig. 1 A. These common aspects and details may not be repeated to avoid obscuring the presently described representative embodiments.

[0038] The console 180 is connected to balloon catheter device 101 via the PIM 106, and as described more fully below, is adapted to provide an interface for a user to heat and expand the balloon in the balloon catheter device, monitor the expansion of the balloon catheter device 101, and make adjustments to the amount of heat (i.e., adjust the temperature) and expansion (i.e., adjust the pressure) applied by the balloon catheter device 101. As such, and as described more fully below, in accordance with various aspects of the representative embodiments, the status of the deployed balloon catheter device 101, including the temperature and pressure, are monitoredreal-time by a clinician / user via the console.

[0039] The balloon catheter device 101 comprises a balloon 102 and a heating element (not shown in Fig. IB). Once deployed, the balloon 102 is expanded to a set pressure via the pump 107. As described more fully below, the pressure of applied to the balloon 102 by the pump 107 can be controlled (e.g., changed) based on inputs to the console 180, such as via an icon (not shown in Fig. IB) of the GUI 142. Besides a direct connection to the console 180, the pump 107 can also be connected to the PIM 106. Alternatively, the pump 107 can be controlled manually.

[0040] The heat applied to the balloon 102 (and thus to the tissue of the blood vessel in the portion where the balloon catheter device 101 is deployed) is set by an energy source 118, which may be, for example, an electrical power supply. As shown, the set point of the temperature are adapted to be displayed at the display 140, and changes to the applied temperature may be made by the user via an icon (not shown in Fig. IB) of the GUI 142.

[0041] The type of heating element (e.g., thermistor, radio frequency (RF) or other electromagnetic heating element, laser heating element, or an ultrasound element) dictates the energy source 118 of the console. As described more fully below, the temperature in the balloon 102 may be monitored real-time during a treatment by system 100 and provided to the display 140. Beneficially, and based on this monitoring, the temperature of the balloon 102 (and thus the tissue of the blood vessel in the region where the balloon catheter device 101 is deployed) can be controlled (e.g., changed) based on inputs to the console 180, such as via an icon (not shown in Fig. IB) on a GUI 142. Among other functions, the control of the temperature applied by the heating element can include increasing the temperature to aid in the treatment of the diseased portion of the blood vessel, and to terminate application of heat when damage can be done to the blood vessel by continued application of heat.

[0042] The console 180 further comprises a temperature acquisition unit 112 and a pressure acquisition unit 114. The temperature acquisition unit 112 is adapted to receive temperature readings from a temperature sensor (not shown in Fig. IB) disposed in the balloon 102. In accordance with a representative embodiment, the temperature acquisition unit 112 comprises an electrical circuit adapted to convert voltage outputs from the temperature sensor to a temperature value based on a known temperature-voltage relationship (e.g., from a look-up table stored in memory). As shown, temperature readings are adapted to be displayed at the display 140.

[0043] As described more fully below, the temperature readings are provided real-time to theconsole and are displayed for review by the user. In one aspect of the present teachings, based on the temperature readings, the controller 150, via the processor 153, is adapted to automatically change the temperature or terminate heating by the heating element to effect various desired ends during the treatment. Moreover, and as described more fully below, the temperature may be adjusted based on real-time temperature readings via inputs on the console 180 (e.g., via an interface on a GUI (not shown in Fig. IB)).

[0044] The pressure acquisition unit 114 is adapted to receive pressure readings from the pump 107 via the PIM 106. Illustratively, the pressure readings would made using a pressure sensor disposed in / at the pump 107. In accordance with a representative embodiment, the pressure acquisition unit 114 comprises an electrical circuit adapted to convert voltage outputs from the pressure sensor to a pressure value based on a known temperature-voltage relationship (e.g., from a look-up table stored in memory). As shown, pressure readings as well as pressure set points are adapted to be displayed at the display 140, and changes to the applied pressure may be made by the user via the GUI 142.

[0045] As described more fully below, the pressure readings are provided real-time to the console and are displayed for review by the user. In one aspect of the present teachings, based on the pressure readings, the controller 150, via the processor 153, is adapted to automatically change the pressure or terminate application of pressure to the balloon 102 to effect various desired ends during the treatment. Moreover, and as described more fully below, the pressure may be adjusted based on real-time temperature readings via inputs on the console 180 (e.g., via an interface on a GUI (not shown in Fig. IB)).

[0046] The console 180 further comprises an imaging transmit signal unit 119 and an imaging receive signal unit 116. In accordance with a representative embodiment, the imaging transmit signal unit 119 comprises a known function / signal generator and the imaging receive signal unit comprises an known electrical circuit that records the signal received from the imaging device, and processes the signal / data to provide an image for display 140. The imaging transmit signal unit 119, via the processor 153 of controller 150, is adapted to provide the requisite signal of the selected imaging unit to imaging device (not shown in Fig. IB) in the balloon catheter device 101 cause the imaging device to acquire images in the balloon catheter device 101 in real-time. As noted above, the imaging transmit signal unit 119 is adapted to provide control signals appropriate for the selected imaging modality (e.g., IVUS imaging device, OCT imaging device,dielectric sensing / imaging device). Notably, as shown by the dotted line, the imaging signal is also provided as an input to an algorithm (executed by the processor 153) used to generate the image. Specifically, to generate the image, the type of imaging transmit signal is required to determine its sequence allowing the algorithm to interpret the image. Just by way of example, when an IVUS array, which is around the circumference of the of the catheter shaft inside the balloon such as shown in Figs. 3A-3B, is used to provide the real-time image, different elements of the array are adapted to activate in a sequence. For the algorithm reconstruct the image, the type and timing of the pulses sent to the IVUS array are needed.

[0047] The imaging receive signal unit 116 receives the signals from the imaging device deployed in the balloon catheter device 101, and provides these received signals as input to the algorithm (executed by the processor 153) for generation of the image and its display on the console. An example of this imaging receive signal unit 116 is an known analogue front-end that may consist of a bandpass filter, low noise amplifier, and analogue to digital conversion. As described more fully below, these real-time images enable the system 100 to automatically effect action, or enable the clinician / user to manually effect action via the console 180 (e.g. via the GUI) based on the images gathered.

[0048] The console 180 comprises a compliance algorithm 122 and an image generation algorithm 124. These algorithms comprise computer executable code, which when executed by a processor, cause the processor to determine the compliance (C), and generate the image based on the imaging device disposed in the balloon catheter device 101 and the cross-sectional area (CSA) of the blood vessel in which the balloon catheter device 101 is deployed, respectively. Just by way of illustration, the instructions may be stored in memory 151, and executed by the processor 153.

[0049] The image generation algorithm 124 in combination with the imaging transmit signal unit 119 can also be utilized to detect changes in the vascular and surrounding tissue properties, altered by the application of heat and pressure, via tracking changes in local image signal intensity (e.g. echogenicity), or assessing tissue stiffness via elastography.

[0050] As shown, data from various inputs are provided to the algorithms to enable the CSA and the compliance. To this end, the image transmit signal unit 119 and the image receive signal unit 116 are provided to the image generation algorithm 124. These data are used to reconstruct the image on the display 140 (an illustrative image is shown in greater detail in Fig. 2).

[0051] The image generation algorithm uses these data to determine the CSA of the vessel in which the balloon catheter device 101 is deployed. (Notably, and as described more fully below, when a vein is being imaged, the CSA of the balloon 102 is substantially the same as the CSA of the vein.) As shown in Fig. 2, the CSA of an arterial lumen may include various kinds of plaque in between the vessel border and the outer surface of the balloon 102.

[0052] In accordance with a representative embodiment, the determination of the CSA comprises first determining the interface of the blood vessel wall with the lumen. The interface can be detected based on a gradient in the image intensity, and can be manually input via the GUI such as via an input of the GUI at the image. Next, the number of pixels is determined in the area inside this interface, and the number of pixels is converted to a cross-sectional area to provide the CSA. This determination may be implemented as an algorithm in computer executable instruction store in memory 151, for example, and executed by processor 153. Notably, this method may be repeated for each image generated for display.

[0053] In certain representative embodiments, the pressure provided by the pump 107 is maintained at a specific level for a certain period of time. With the heat applied, the balloon 102 expands with the expansion of the blood vessel cause by the applied heat. As such, changes in the CSA (e.g., increases) caused by applied heat can be indicative of healing of the diseased blood vessel caused by the heat and the applied balloon pressure. Based on the calculated CSA, decisions regarding the duration of the currently applied level of heat and changes to the applied level of heat can be made by the clinician / user. For example, and as described more fully below, there are times when plateaus are reached, and the desired steady expansion of the blood vessel cause by the heat and the balloon 102 ceases. In some instances, these plateaus can be overcome by increasing the temperature applied by increasing the output of the energy source 118. As such, either by manual change by the clinician / user upon observing these plateaus, or automatically based on instructions executed by the processor 153, the temperature can be raised to see if further heating is useful. Just by way of illustration, when a plateau is reached such as described in connection with Fig. 2, its duration can be monitored. If the duration of the plateau exceeds a predetermined time interval, the system 100 is adapted to provide a visual and / or an audio indication that the plateau is too great. Upon this indication, the clinician can cease application of heat.

[0054] Once the CSA is determined by the image generation algorithm 124, these data may beused by the compliance algorithm 122 to determine the compliance. Specifically, changes in the set pressure (AP) over a particular time interval are provided from the pump 107 to the compliance algorithm 122, and changes in the CSA (AA) are provided from the image generation algorithm 124, allowing for the determination over time of the compliance (C=AA / AP) in real time and over a diagnosis / treatment period. As described more fully below, the compliance versus time, or the CSA versus time, or both, may be shown on the display 140, and the compliance and / or the CSA usefully monitored in real-time, enabling the system 100, either automatically or manually, to alter the treatment. Just by way of illustration, when the compliance and / or the CSA versus time hits a plateau, the temperature provided by the heating element of the balloon catheter device from the energy source 118 may be increased, and resulting in a change in the compliance and / or CSA. This change in the compliance and / or the CSA may increase steadily, or suddenly. The former allows for decisions to be made to maintain the temperature and / or pressure for a certain period of time, or to increase the temperature and / or pressure. The latter can indicate that one of these collagen webs impeding the diseased blood vessel broke. Similarly, the pressure in the balloon catheter device 101 may increase at an unacceptable rate, which, for example, may be indicative of the balloon’s bursting. The image generation algorithm the algorithm may terminate the procedure either through a warning on the console 180. Moreover, Notably, there may be a threshold temperature for the maximum temperature to be applied to the blood vessel. The algorithm may terminate the procedure to avoid damaging the blood vessel from overheating. This termination may be done manually based on an alarm on the console 180, or can be carried out automatically when the threshold is reached.

[0055] As will be appreciated, measurement of the compliance requires a change in the pressure. Illustratively, to assess compliance, a pressure variation may be created by the pump 107. For example, the pump 107 may be adapted to cause a sinusoidal pressure variation, where the amplitude of the sinusoid is selected to be a function of the pressure (e.g., 10% of the nominal pressure). This variation may be carried out based on an input by the clinician (e.g., via the GUI) with the change implemented by execution of instructions by the processor 153 that are stored in memory 151.

[0056] The console 180 also comprises a display 140. As shown in more detail in connection with Fig. 2, the display is configured to provide real-time values of the temperature and pressurein the balloon catheter device 101, the CSA and the compliance versus time. Additionally, the set points and actual measures of temperature can be displayed, where the balloon temperature is substantially equal to the set temperature. As shown in Fig. 2 in accordance with a representative embodiment, the output images from the image sensing device can be displayed. Based on these data, and as noted above, the vessel diameter can be determined and displayed. Finally, vascular changes in real-time can be shown on the display, allowing the clinician / user to detect these changes and take action as needed.

[0057] The display 140 may include a GUI 142. As described more fully below, based on readings on the display, the GUI 142 allows the clinician / user to set and / or make changes to, for example, the pressure and / or the temperature applied to the balloon catheter device 101.

[0058] Fig. 2 illustrates a display 200 comprising a GUI used in a system 100 for thermal balloon angioplasty in accordance with a representative embodiment. Various aspects and detail of the presently described representative embodiments may be common to those described in connection with the representative embodiments of Figs. 1A-1B. These common aspects and details may not be repeated to avoid obscuring the description of the display 200 and GUI described in connection with Fig. 2. The display 200 comprises an image from the balloon catheter device 101 disposed in a blood vessel 205, which in the presently described representative embodiment is an artery. Notably, the region 232 shows the tissue surrounding the blood vessel 205 based on the maximum imaging diameter specific to the selected imaging device. Region 206 is the external elastic lamina, and as is known includes the reference vessel that is used to measure the percentage occlusion. An inner circle 204 depicts the diameter of the balloon deployed in the blood vessel 205. As such, region 205 is a part of the vessel wall immediately outside the external elastic lamina of region 206.

[0059] The inner circle 204 shows the CSA vessel lumen derived from the imaging signal from the selected imaging device. Illustratively, the imaging device is an IVUS device, and based on the received imaging signal data, a border detection algorithm is used to determine the boundary of the inner circle. Such border detection algorithms are known, and determine boundaries, for example based on image intensity gradients. Such algorithms may be part of the image generation algorithm 124. Illustratively, the border detection algorithm is stored in memory 151 as computer executable instructions, which when executed by the processor 153 generate not only the image shown in Fig. 2, but also determine the CSA. In accordance with a representativeembodiment, this calculated area is displayed at icon 216 for every image generated. For example, this calculated area can be determined at a typical frame rate of 30 fps. Notably, the minimum and maximum diameters can be displayed as shown. Displaying the minimum and maximum diameters is useful in determining the eccentricity (non-circularity) of the vessel being imaged due to a lesion or compression.

[0060] The blood vessel 205 depicts a feature of the blood vessel wall that is detected per the imaging system, representing the location of the external elastic lamina of the blood vessel and commonly noted as the reference vessel for the purpose of sizing. The corresponding diameter or area measurement 208 may be used to calculate the percentage of lumen area that is reduced due to the lesion per icon 218 within the cross-sectional view 202. The inner circle 204 is essentially the expanded balloon disposed in the vessel lumen, which is narrowed due to the presence of a vascular lesion 234, for example. Notably, the balloon is inflated and the lumen diameter is substantially the same as the balloon diameter. Because of the vascular lesion 234 in the artery, the balloon is shown with limited expansion. However, in accordance with the present teachings, a clinician / user monitoring the procedure can increase the heat and / or applied pressure provided via the balloon catheter device 101, to increase the diameter of the inner circle 204. Alternatively, based on this monitoring, the clinician / user may terminate application of heat to avoid damaging the tissue of the blood vessel 205 and the surrounding vascular tissue in region 232. In accordance with a representative embodiment, this calculated area is displayed at icon 216 such as described above.

[0061] Notably, if the blood vessel 205 depicted in Fig. 2 were a vein and not an artery, the region of vascular lesion 234 may be minimal or non-existent, and only the diameter of the inner circle 204 of the vein (and the balloon) would be determined by the image generation algorithm 124. However, there may be instances where the lumen diameter and the reference vessel diameter could be determined. Again, as alluded to above, and as described more fully below, the clinician / user monitoring the procedure could make decisions on the duration and magnitude of the heat or pressure applied.

[0062] The display 200 also comprises a graph 210 of compliance versus time during the procedure. Additionally, or alternatively, the CSA of the vessel (and the balloon) versus time can be provided on the display 200 via icon 212 of the GUI. In regions 242, 246 and 250, the compliance is shown to be increasing as a result of the applied heat and / or pressure selected ineach region. In regions 244, 248 and 252, the compliance remains substantially unchanged. During the periods of regions 244, 248, 252, decisions can be made regarding the next step in the treatment. For example, when region 248 is reached, the level of applied heat and / or pressure can be increased by to increase the compliance. Similarly, if the graph 210 were CSA versus time, when region 244 is reached, the level of applied heat and / or pressure can be increased to increase the CSA. This result of this change is realized in region 246.

[0063] In accordance with a representative embodiment, and as noted above, the display may comprise a GUI, which allows the clinician / user to change the temperature in the balloon 102, or to change the pressure in the balloon 102 or both. For example, inputs to a pressure and temperature set point icon 214 allows the user to selectively adjust the temperature and pressure. This procedure can be repeated when the plateau in region 248 is reached, and the compliance (or CSA) can be increased as shown in region 250. In this way, the compliance and the CSA of the blood vessel can be increased resulting in increased blood flow as a result of the treatment of the representative embodiment. As such, the patient’s vascular health is improved by the monitoring of the compliance and CSA of the blood vessel being treated, and the actions taken using the console 180 in accordance with the present teachings.

[0064] As noted above, care must be taken to avoid overheating the blood vessel 205 to avoid damaging the blood vessel 205. Moreover, the duration that the balloon catheter device 101 is deployed must also be monitored because during deployment of the balloon 102, blood flow in the blood vessel 205 is restricted, and can result in harm to the patient undergoing the procedure. As alluded to above, threshold levels of temperature, or pressure, or duration of deployment of the balloon 102 can be set, and the instructions can cause the processor 153 to terminate the application of heat, or deployment of the balloon 102, or both. Alternatively, these thresholds may trigger warnings (e.g. audio warnings) when a threshold is reached, and application of heat, and / or pressure to the components of the balloon catheter device 101 can be manually terminated by the clinician / user monitoring the procedure.

[0065] Fig. 3 A is a simplified block diagram of a system 300 for thermal balloon angioplasty, in accordance with a representative embodiment. Various aspects and detail of the presently described representative embodiments may be common to those described in connection with the representative embodiments of Figs. 1A-2. These common aspects and details may not be repeated to avoid obscuring the description of the system 300 described in connection with Fig.3A.

[0066] The system 300 comprises a balloon 302 in which a guidewire lumen 304 is disposed. A thermistor 306 is positioned to generate heat and measure the temperature in the balloon 302. Alternatively, a known laser (not shown) may be used to apply heat. In yet another representative embodiment, the pump 107 may comprise a heating element and the pump infuses warm fluid to the balloon. Thermistors / thermocouples within the balloon allow temperature within balloon to be adjusted via adjusting the temperature and flow rate of the fluid into the balloon.

[0067] An imaging system 307 is disposed as shown on the guidewire lumen. As noted above, one of a number of imaging systems are contemplated. Notably, the imaging system 307 and thermistor 306 is adapted to be moved along the axis of the guidewire lumen 304 inside the balloon 302.

[0068] The system further comprises a fluid communication lumen 310 to enable inflation and deflation of the balloon 302. The balloon catheter device is connected via a PIM 308. The PIM 308 comprises a pressure interface 312, an image / CSA module 314 and a temperature control module 318. As described above, the PIM is configured to send signal to and receive signals from the console 180 during operation of the balloon catheter device in a procedure as described above. As described more fully above, console 180 processes data that are received to display various data relevant to the procedure, including temperature, pressure; compliance versus time, cross sectional area vs. time; temperature and pressure setpoints; real time measurements; and image and vessel diameter measurements.

[0069] The guidewire lumen 304 facilitates catheter delivery to the lesion. At the distal (balloon) end, thermistors 306 are located within the balloon 302 and are used to generate heat and monitor temperature. The thermistor can be a metal (e.g. Al or Al / Si) embedded in a flexible substrate (e.g. polyimide) to enable wrapping it around a tubular structure. F2R technology can be used to create a solid chip to bond electrical wires to. Alternatively, the thermistor 306 can be embedded in silicon chip. For the temperature sensing-element a thermocouple may alternatively be used. The temperature of the thermistor can be controlled / kept constant via a Wheatstone bridge. In a representative embodiment, the effective temperature can be for example <70°C for 15 s or 45 °C for 3 minutes to produce the desired treatment effect.

[0070] Over the catheter shaft providing the guidewire lumen, during a procedure the imaging system 307 can be delivered and positioned within the balloon 302. In a representativeembodiment, the imaging system 307 may be an IVUS system and may be a separate catheter that runs within a balloon catheter that is designed for compatibility with the IVUS device, or it may be integrated into the balloon system and remain in a fixed position. Fluid is administered in the annular space around the IVUS catheter in a coaxial catheter design, or through a separate inflation lumen as in a multi-lumen catheter design. Upon completion of the thermal angioplasty procedure, fluid is rapidly removed from the balloon and may be replaced with a lower temperature fluid to cool the tissue if desired. Alternatively, cool fluid (i.e. saline) may be administered through an infusion port along the catheter length, which can in turn aid in lowering the temperature on the up or downstream side of the balloon that is in contact with the blood to protect against heat transfer from the catheter to the blood.

[0071] Finally, as noted above, the IVUS device is merely an illustrative example of an imaging device contemplated for the present teachings. Alternatively, and just by way of example, the imaging device may be an optical coherence tomography (OCT) device, in an OCT a rotating element (not shown) is disposed inside center of the balloon. A guide wire lumen at the location of the balloon is then not possible. So the rotating shaft with the imaging element are disposed in the center of the balloon. The guide wire then run along the outside of the balloon or is retracted with the catheter is in place.

[0072] Fig. 3B is a simplified block diagram of a system 320 for thermal balloon angioplasty, in accordance with a representative embodiment. Various aspects and detail of the presently described representative embodiments may be common to those described in connection with the representative embodiments of Figs. 1A-3A. These common aspects and details may not be repeated to avoid obscuring the description of the system 320 described in connection with Fig. 3A.

[0073] The system 320 comprises a balloon 322 in which a guidewire lumen 324 is disposed. A thermistor 326 is positioned to generate heat and measure the temperature in the balloon 322. An imaging system 327 is disposed as shown via the guidewire lumen 324. As noted above, one of a number of imaging systems are contemplated. The system further comprises a fluid communication lumen 310. The balloon catheter device is connected via a PIM 328 to the console 180. The PIM comprises a pressure interface 332, an image / CSA module 314 and a temperature control module 336. As described above, the PIM is configured to send signal to and receive signals from the console 180 during operation of the balloon catheter device in aprocedure as described above. As described more fully above, console 180 processes data that are received to display various data relevant to the procedure, including temperature, pressure; compliance versus time, cross sectional area vs. time; temperature and pressure setpoints; real time measurements; and image and vessel diameter measurements.

[0074] The guidewire lumen 324 facilitates catheter delivery to the lesion. At the distal (balloon) end, thermistors 326 are located within the balloon 322 and are used to generate heat and monitor temperature. The thermistor can be a metal (e.g. Al or Al / Si) embedded in a flexible substrate (e.g. polyimide) to enable wrapping it around a tubular structure. F2R technology can be used to create a solid chip to bond electrical wires to. Alternatively, the thermistor 326 can be embedded in silicon chip. For the temperature sensing-element a thermocouple may alternatively be used. The temperature of the thermistor can be controlled / kept constant via a Wheatstone bridge. In a representative embodiment, the effective temperature can be for example <70°C for 15 s or 45 °C for 3 minutes to produce the desired treatment effect.

[0075] Over the shaft that contains the guidewire lumen, during a procedure the imaging system 327 can be delivered and positioned within the balloon 322. In a representative embodiment, the imaging system 327 may be an IVUS system and may be a separate catheter that runs within a balloon catheter that is designed for compatibility with the IVUS device, or it may be integrated into the balloon system and remain in a fixed position. Fluid is administered in the annular space around the IVUS catheter in a coaxial catheter design, or through a separate inflation lumen as in a multi-lumen catheter design. Upon completion of the thermal angioplasty procedure, fluid is rapidly removed from the balloon and may be replaced with a lower temperature fluid to cool the tissue if desired. Alternatively, cool fluid (e.g., saline) may be administered through an infusion port along the catheter length, which can in turn aid in lowering the temperature on the up or downstream side of the balloon that is in contact with the blood to protect against heat transfer from the catheter to the blood.

[0076] Fig. 4 is a simplified block diagram of a system 400 for thermal balloon angioplasty, in accordance with a representative embodiment. Various aspects and detail of the presently described representative embodiments may be common to those described in connection with the representative embodiments of Figs. 1A-3B. These common aspects and details may not be repeated to avoid obscuring the description of the system 400 described in connection with Fig. 4.

[0077] The system 400 comprises a balloon 402 in which a guidewire lumen 404 is disposed. A temperature sensor 406 is positioned to measure the temperature in the balloon 402. The temperature sensor may be a thermistor or a thermocouple, for example.

[0078] An imaging system is disposed via the guidewire lumen 404. As noted above, one of a number of imaging systems are contemplated. The system further comprises a fluid communication lumen 410. The balloon catheter device is connected via a PIM 408 to the console 180. The PIM comprises a pressure interface 412, an image / CSA module 414 and a temperature control module 418. As described above, the PIM 408 is configured to send signal to and receive signals from the console 180 during operation of the balloon catheter device in a procedure as described above. As described more fully above, console 180 processes data that are received to display various data relevant to the procedure, including temperature, pressure; compliance versus time, cross sectional area vs. time; temperature and pressure setpoints; real time measurements; and image and vessel diameter measurements.

[0079] The system 400 is similar to the systems 300, 320 except that electromagnetic energy is used to heat the fluid inside the balloon (and surrounding tissue) instead of the thermistors. In accordance with a representative embodiment, the electromagnetic energy is in the radio frequency (RF) band. Heat application is controlled via electrical voltage and frequency applied by an RF generator. Typical frequencies used for heating tissue are in the 500kHz range but can be as low are 20 kHz or high as 5MHz. This can be done in either a monopolar or bipolar approach. In the monopolar configuration electrodes may be disposed in the balloon 402 and a patch is placed on the skin of the patient. The electrical current then runs from the electrodes 405, 407 in the balloon 402 to the electrode in the patch. In the bi-polar configuration two or more electrodes are inside the balloon, with the current running in between the electrodes inside the balloon.

[0080] The system further comprises a fluid communication lumen 410 disposed between the balloon catheter device and the PIM 408.

[0081] Fig. 5 is a simplified block diagram of a system 500 for thermal balloon angioplasty, in accordance with a representative embodiment. Various aspects and detail of the presently described representative embodiments may be common to those described in connection with the representative embodiments of Figs. 1A-4. These common aspects and details may not be repeated to avoid obscuring the description of the system 500 described in connection with Fig. 15.

[0082] The system 500 comprises a balloon 502 in which a guidewire lumen 504 is disposed. A temperature sensor 506 is positioned to measure the temperature in the balloon 502. The temperature sensor 506 may be a thermistor or a thermocouple, for example.

[0083] An imaging system is located in the balloon similar as in Figs 3A-4. As noted above, one of a number of imaging systems are contemplated. The system further comprises a fluid communication lumen 510. The balloon catheter device is connected via a PIM 508 to the console 180. The PIM comprises a pressure interface 512, an image / CSA module 514 and a temperature control module 518. As described above, the PIM is configured to send signal to and receive signals from the console 180 during operation of the balloon catheter device in a procedure as described above. As described more fully above, console 180 processes data that are received to display various data relevant to the procedure, including temperature, pressure; compliance versus time, cross sectional area vs. time; temperature and pressure setpoints; real time measurements; and image and vessel diameter measurements.

[0084] The system 500 is similar to the system 400 except electrodes 505, 507 and temperature sensor 506 are disposed on an outer surface of the balloon 502 and close to the vessel tissue 530. Heat application is controlled via electrical voltage and frequency applied by an RF generator, which generates an electric field 509. Typical frequencies used for heating tissue are in the 500kHz range but can be as low are 20 kHz or high as 5MHz. This can be done in either a monopolar or bipolar approach. In the monopolar configuration electrodes may be disposed in the balloon 502 and a patch is placed on the skin of the patient. The electrical current then runs from the electrodes 505, 507 in the balloon 502 to the electrode in the patch. In the bi-polar configuration two or more electrodes are inside the balloon, with the current running in between the electrodes inside the balloon.

[0085] The system further comprises a fluid communication lumen 510 disposed between the balloon catheter device and the PIM 508.

[0086] In the representative embodiment, the system 500 uses dielectric impedance sensing to determine the CSA. Additionally, changes in the lesion, vessel wall or surrounding tissue that indicate therapeutic effect can be detected by spectral electrical impedance sensing with the electrodes 505 and 507.

[0087] Fig. 6 is a simplified block diagram of a system 600 for thermal balloon angioplasty, inaccordance with a representative embodiment. Various aspects and detail of the presently described representative embodiments may be common to those described in connection with the representative embodiments of Figs. 1A-5. These common aspects and details may not be repeated to avoid obscuring the description of the system 600 described in connection with Fig. 6A.

[0088] The system 600 comprises a balloon 602 in which a guidewire lumen 604 is disposed. A thermistor 606 is positioned to generate heat and measure the temperature in the balloon 602. An imaging system comprising electrodes 605 and 607 is disposed as shown via the guidewire lumen 604. The electrodes 605, 607 are used to effect dielectric sensing to assess the CSA. Further details of this sensing can be found in commonly owned U.S. Patent Application No. 20220054038 Al, the entire disclosure of which is specifically incorporated by reference.

[0089] The system further comprises a fluid communication lumen 610. The balloon catheter device is connected via a PIM 608. The PIM comprises a pressure interface 612, an image / CSA module 314 and a temperature control module 318. As described above, the PIM is configured to send signal to and receive signals from the console 180 during operation of the balloon catheter device in a procedure as described above. As described more fully above, console 180 processes data that are received to display various data relevant to the procedure, including temperature, pressure; compliance versus time, cross sectional area vs. time; temperature and pressure setpoints; real time measurements; and image and vessel diameter measurements.

[0090] The guidewire lumen 604 facilitates catheter delivery to the lesion. At the distal (balloon) end, thermistors 606 are located within the balloon 602 and are used to generate heat and monitor temperature. The thermistor can be a metal (e.g. Al or Al / Si) embedded in a flexible substrate (e.g. polyimide) to enable wrapping it around a tubular structure. F2R technology can be used to create a solid chip to bond electrical wires to. Alternatively, the thermistor 606 can be embedded in silicon chip. For the temperature sensing-element a thermocouple may alternatively be used. The temperature of the thermistor 606 can be controlled / kept constant via a Wheatstone bridge. In a representative embodiment, the effective temperature can be for example <70°C for 15 s or 45 °C for 3 minutes to produce the desired treatment effect.

[0091]

[0092] Fig. 7 is a graph 700 of impedance versus tissue pressure from a system for thermal balloon angioplasty in accordance with a representative embodiment. The impedance ismeasured, for example, using the system 500 described in connection with Fig. 5 above.

[0093] Region 702 shows the effect of heating at a comparatively low temperatures, where viscoelastic changes in the blood vessel may occur, but chemical changes in the tissue of the blood vessel generally do not occur.

[0094] Region 704 shows the beginning of denaturation of the tissue causes a chemical change in tissue structure, subsequently changing the trend of impedance behavior.

[0095] Region 706 shows the effect of heating up to a temperature of approximately 100 °C. At this temperature, the evaporation of liquids dehydrates the tissue substantially, resulting in a significant change in the impedance of the tissue as shown.

[0096] Although systems and methods for monitoring and controlling a medical procedure have been described with reference to several exemplary embodiments, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of peripheral vascular pressure gradient determination in its aspects. Although peripheral vascular pressure gradient determination has been described with reference to particular means, materials and embodiments, peripheral vascular pressure gradient determination is not intended to be limited to the particulars disclosed; rather peripheral vascular pressure gradient determination extends to all functionally equivalent structures, methods, and uses such as are within the scope of the appended claims.

[0097] The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of the disclosure described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.

[0098] One or more embodiments of the disclosure may be referred to herein, individually and / or collectively, by the term “invention” merely for convenience and without intending tovoluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.

[0099] The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter.

[0100] The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to practice the concepts described in the present disclosure. As such, the above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present disclosure. Thus, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents and shall not be restricted or limited by the foregoing detailed description.

Claims

CLAIMS:

1. A medical system (100), comprising: an inflatable balloon (102) adapted to be deployed in a blood vessel (205) lumen; a pressure source adapted to inflate and deflate the balloon (102); a heating element disposed in the balloon (102) and adapted to provide heat to the blood vessel (205) lumen; a sensing device disposed in the balloon (102); a processor (153); a tangible, non-transitory computer readable medium that stores instructions, which when executed by the processor (153), cause the processor (153) to: based on data received from the sensing device, generate cross-sectional data of the balloon (102) and / or blood vessel (205) where the balloon (102) is deployed; and a display (140) adapted to show the cross-sectional data of the balloon (102) and the blood vessel (205).

2. The system (100) of claim 1, wherein the processor (153) is further adapted to display (140) a graph (210) of the cross-sectional data versus time, or cross-sectional versus pressure, or both.

3. The system (100) of claim 1, wherein the processor (153) is further adapted to determine a cross-sectional area of a blood vessel (205) lumen from the cross-sectional data.

4. The system (100) of claim 3, wherein the processor (153) is further adapted to determine the compliance from a change in the cross-sectional area and a change in the pressure.

5. The system (100) of claim 3, wherein the processor (153) is further adapted to display (140) a graph (210) of a compliance versus time.

6. The system (100) of claim 1, further comprising a temperature sensor (406) disposed in the balloon (102) and adapted to measure the temperature inside the balloon (102), or on the outside of the balloon (102), or both.

7. The system (100) of claim 6, further comprising a graphic user interface (GUI (142)) connected to the display (140), wherein via input on the GUI (142), the processor (153) is adapted to change one or more of the temperature and the pressure in the balloon (102).

8. The system (100) of claim 7, wherein via the GUI (142), the processor (153) is adapted to provide a warning signal when a threshold temperature or electrical impedance of the tissue is reached.

9. The system (100) of claim 7, wherein via the GUI (142), the processor (153) is adapted to display a threshold comprising a point of saturation on the graph of the cross-sectional area and / or compliance versus time to determine a treatment status.

10. The system of claim 1, wherein the display is further adapted to show changes in vascular tissue properties.

11. The system of claim 10, wherein the processor, based on the changes to vascular tissue properties, is adapted to alert a user, or terminate an application of heat or pressure to the balloon, or both.

12. The system of claim 1, wherein the heating element comprises a thermistor, a radio frequency (RF) heating source, a laser, or an ultrasound heating device.

13. The system of claim 1, wherein the cross-sectional data-generating device comprises an intravascular ultrasound (IVUS) imaging device, an optical coherence technology (OCT) imaging device, or a dielectric sensing device.

14. A method of monitoring a medical procedure, the method comprising: providing heat during balloon pressurization to expand a blood vessel lumen; generating cross-sectional data of the balloon and / or blood vessel where the balloon is deployed; displaying the cross-sectional data of the balloon and / or blood vessel; providing an input to a graphic user interface (GUI); and changing the heat provided to the balloon, or changing the pressure applied to the balloon, or both via an input on the GUI.

15. The method of claim 14, further comprising displaying a graph of the cross-sectional data versus time and / or pressure.

16. The method of claim 14, further comprising determining a cross-sectional area of a blood vessel lumen from the cross-sectional data.

17. The method of claim 13, further comprising determining a compliance from a change in the cross-sectional area and a change in the pressure.

18. The method of claim 16, further comprising displaying a graph of a compliance versus time.

Images