Intravascular resistance measurement device and related method for interpreting condition of blood vessel

Abstract

Provided herein are intravascular devices and related systems and methods for interpreting vascular conditions (e.g., by measuring flow resistance). Selectively inflatable first and second balloons are disposed at the distal end portion of the catheter body and spaced apart from each other. The one or more ports are arranged between the first balloon and the second balloon at intervals along the catheter body. The second balloon is repositionable relative to the first balloon.

Description

[0001] Cross-reference to related applications: This application claims priority to U.S. Patent Application No. 18 / 218,737, filed July 6, 2023, which in turn claims priority to U.S. Provisional Patent Application No. 63 / 457,891 (hereinafter referred to as "Provisional Application '891"), filed April 7, 2023, and U.S. Provisional Patent Application No. 63 / 367,784, filed July 6, 2022; and this application also claims priority to Provisional Application '891. The disclosures of all the above applications are incorporated herein by reference in their entirety. Technical Field

[0002] Exemplary embodiments generally relate to apparatus, systems, and methods for measuring fluid resistance within blood vessels (such as human veins) with the aim of interpreting vascular conditions such as vascular occlusion or stenosis. Background Technology

[0003] Sometimes blood vessels become completely or partially blocked and / or narrowed due to one or more lesions, which can lead to poor blood circulation and a variety of medical complications. Several techniques exist to treat such blocked and / or narrowed vessels to improve blood flow. Understanding the degree of occlusion (e.g., length, extent, and / or type) is often important, but measuring these intravascular features in a living patient, especially in a relatively minimally invasive manner, remains challenging. Existing techniques for examining such occlusions include various imaging techniques such as intravascular ultrasound (IVUS), computed tomography (CT), magnetic resonance imaging (MRI), and venography—a catheter-based diagnostic procedure that images the interior of veins, essentially providing a real-time view. These techniques have limitations because they rely on the external appearance of the vessel. Veins and other blood vessels generally have high compliance, making accurate assessment based on appearance difficult. Furthermore, existing imaging techniques typically focus on only one plane at a time, presenting other drawbacks. Moreover, such measurements often require inflating the vessel to artificially high pressure, failing to accurately simulate the physiological state of the vessel. Summary of the Invention

[0004] There is a pressing need for an alternative means of measuring internal characteristics of blood vessels. This document provides apparatus, systems, and methods for measuring resistance characteristics within vascular systems, such as human veins, which can be used to determine the hemodynamic significance of abnormalities or lesions. In exemplary embodiments, vascular conditions, such as (but not limited to) occlusion or stenosis, can be understood by interpreting resistance characteristics.

[0005] A distal end of an intravascular device can include at least two balloons spaced apart. The distal end of the device can be inserted into a vasculature of a subject under study and can be pushed along a guidewire to a site of interest (which can or can not have one or more blockages, but does not necessarily require a blockage). The region between the two balloons can define a region of interest. A first balloon, proximal to the other, can be inflated to substantially block normal blood flow within the vessel. Fluid can be injected through a port on the catheter between the two balloons at a controlled flow rate or pressure. A second balloon, distal to the other, can be adjusted to change the flow characteristics of the injected fluid. In this way, the volume and / or pressure of the fluid can be determined and the resistance can be calculated.

[0006] The flow characteristics of the injected fluid can be changed in a number of ways, such as by changing the pressure of the injected fluid (e.g., by adjusting the volume of fluid injected and / or the inflation level of the distal balloon), changing the volume of the region of interest (e.g., by adjusting the relative positions of the two balloons and thus the length of the region of interest), inflating, deflating, or repositioning the balloons (e.g., by adjusting the gap between the balloons and the blockage). Changes in flow rate and / or resistance can then be measured.

[0007] Vessels that are more elastic can have a relatively stable resistance to changes in volume or pressure because such vessels can accommodate changes in flow rate by volume adjustment. Vessels that are less elastic can have a greater change in resistance to changes in volume or pressure because such vessels can have difficulty accommodating changes in flow rate by volume adjustment. The elasticity of a vessel can be an indicator of the health of the vessel: vessels that are less elastic can generally indicate a stenosis or a lesion, while vessels that are more elastic can generally indicate a relatively healthy vessel.

[0008] Additionally or alternatively, the flow rate through the distal balloon can increase and / or the back pressure can decrease when the gap between the distal balloon and the surrounding tissue increases (e.g., the fit loosens), and the flow rate through the distal balloon can decrease and / or the back pressure can increase when the gap between the distal balloon and the surrounding tissue decreases (e.g., the fit tightens). In this way, the size of the vessel and / or blockage can be measured.

[0009] Subsequently, the balloons can be used to perform a treatment, such as, but not limited to, angioplasty, stent implantation, drug delivery (e.g., through a drug coating), or a combination thereof.

[0010] Measurements can be taken at one or more regions to generate data, interpretations, and / or visualizations of vessels (e.g., veins) in a vasculature of a human subject. For example, measurements can be taken before and after a treatment to assess the effectiveness of the treatment.

[0011] The distal balloon and / or occlusion balloon can also be used to perform a number of treatments at the vessel, such as angioplasty.

[0012] Although this document sometimes uses veins as an example, as a further non-limiting example, this disclosure may also be applied to arteries or other vascular-related applications.

[0013] The following description, in conjunction with the accompanying drawings, details other features and advantages of the systems and methods of this disclosure, as well as the structure and operation of various aspects of this disclosure. Attached Figure Description

[0014] In addition to the features described above, other aspects of the invention will become clear from the following description of the drawings and exemplary embodiments. In the various views, the same reference numerals denote the same or equivalent features, wherein:

[0015] Figure 1 This is a plan view of an exemplary intravascular measurement system, with section line AA and detail A labeled.

[0016] Figure 2 for Figure 1 A detailed side view of the distal end of the vascular measurement device in the system shown.

[0017] Figure 3 for Figure 1 A detailed side view of another exemplary embodiment of the distal end of the vascular measurement device in the system shown;

[0018] Figure 4 For along Figure 1 The section line AA is used to extract the content of the section line. Figures 1 to 3 Front sectional view of the embodiment shown;

[0019] Figure 5 For operation Figures 1 to 4 Exemplary logic flowcharts of the systems and devices shown;

[0020] Figure 6 for Figure 1 A detailed side sectional view of another exemplary embodiment of the vascular measurement device in the system shown, along... Figure 7 The section line BB in the middle is cut off;

[0021] Figure 7 For along Figure 1 The section line AA is used to extract the content of the section line. Figure 6 Front sectional view of the embodiment shown;

[0022] Figure 8 For operation Figures 6 to 7 Exemplary logic flowcharts of the systems and devices shown;

[0023] Figure 9 For it to be passable Figures 1 to 8 A floor plan of an exemplary visual display interface generated by the system, apparatus and / or method shown;

[0024] Figure 10 FIG. 1 shows a plan view of an exemplary system in use in an exemplary blood vessel; Figures 1 to 9

[0025] Figure 11 FIG. 2 shows a plan view of the system of FIG. 1 in use in a second exemplary blood vessel; Figure 10

[0026] Figure 12 FIG. 3 shows a plan view of another exemplary embodiment of the system of FIG. 1 in use in another exemplary blood vessel. Figures 10 to 11 DETAILED DESCRIPTION

[0027] Various embodiments of the present application will be described in detail below with reference to the drawings. In the following description, specific details are provided to assist in a thorough understanding of these embodiments of the present application. It will be apparent, however, that various modifications and changes can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, descriptions of well-known functions and constructions can be omitted for clarity and conciseness.

[0028] Embodiments of the present application will be described herein below with reference to schematic drawings of idealized embodiments (and intermediate structures) of the present application. As such, deviations from the shapes of the regions illustrated herein can occur as a result of, for example, manufacturing processes and / or tolerances, and are to be expected. Embodiments of the present application should not be construed as limited to the particular shapes of regions illustrated herein, but are to include deviations in shapes that result from, for example, manufacturing. Thus, embodiments of the present application are to encompass regions that can not be identical to a given idealized region illustrated herein, but which are nevertheless equivalent in function and / or result to the regions that they approximate.

[0029] Figure 1 An exemplary system 10 for measuring a blood vessel feature within a passageway is shown. In an exemplary embodiment (non-limiting), the system 10 can be configured to measure blood flow resistance within a human vein, but the system 10 can also be adapted to measure any type of fluid within any type of blood vessel passageway of any animal. The measured flow rate and / or resistance characteristics can be used to interpret certain blood vessel conditions, such as (but not limited to) the presence, size, and / or nature of an occlusion, and the degree of stenosis.

[0030] The relationship between pressure, force, and volume is known. For example, it is known that pressure is equal to force times volume. Thus, by controlling the volume and the pressure, the magnitude of the force can be calculated. In a blood vessel structure, if a known pressure is applied within a known study region (i.e., volume is known), the magnitude of the force can be calculated. When the pressure and / or volume are adjusted, changes (or lack of changes) in the force can indicate whether the passageway is relatively more elastic (typically a healthy condition) or stiffer and / or has a stenosis (typically a diseased condition).

[0031] ​​​A fluid having certain known characteristics can be provided and / or injected within a portion of the vasculature. In this manner, the pressure of the fluid within the study region can be known. The fluid can be partially, substantially (e.g., > 95%) or completely (e.g., > 99%) confined within the study region by a first balloon 42 (sometimes referred to herein as an "occlusion balloon") and a second balloon 44 (sometimes referred to herein as a "variable size balloon," a "measurement balloon" or a "treatment balloon") of the proximal end. In this manner, the volume of the study region can be known and / or determined (e.g., based on the size of the isolated vascular region between the two balloons 42, 44). Since the pressure and volume of the fluid within the study region are known, the resistance to flow of the fluid can be calculated.

[0032] The volume of the study region and / or the pressure of the fluid can be varied in a number of ways, such as by injecting additional fluid (e.g., saline, contrast, or a combination thereof), by removing some of the fluid, by adjusting the flow rate of the injected fluid, and / or by adjusting the position of the first balloon 42 relative to the second balloon 44. By these manipulations, the changes in flow rate and / or resistance under different conditions can be measured. The response of the tissue to these changes can indicate the level of elasticity of the vessel, which in turn can reflect the health or diseased state of the vessel. When the pressure and / or volume of the injected fluid is varied, if the vessel is relatively more elastic, the resistance measurements will be relatively stable, as the vessel can accommodate the higher pressure and / or increased flow by volume adjustments, for example; if the vessel is relatively less elastic, the resistance measurements will vary more as the volume and / or pressure of the fluid is varied, as the vessel has difficulty accommodating these changes by volume adjustments.

[0033] Additionally or alternatively, when the gap between the distal balloon 44 and the surrounding tissue increases (e.g., the fit loosens), the flow rate through the distal balloon 44 can increase and / or the back pressure can decrease; when the gap between the distal balloon 44 and the surrounding tissue decreases (e.g., the fit tightens), the flow rate through the distal balloon 44 can decrease and / or the back pressure can increase. In this manner, the size of the vessel and / or obstruction can be measured.

[0034] Measurements can be taken at different segments of the vessel to assess the elasticity and / or condition of the vessel. Measurements can be taken before and after treatment to assess the effectiveness of the treatment.

[0035] The system 10 can include a catheter device 12. The catheter device 12 can include a distal portion 18 that can be coupled to a catheter tube 16 that extends from a handle assembly 14. The catheter tube 16 and / or the distal portion 18 can be configured to be implanted and / or navigated within a portion or all of a human vasculature. For example, and without limitation, the catheter tube 16 and / or the distal portion 18 can be flexible, can be made of one or more biocompatible materials, and / or can be configured for single use or for repeated use after conventional sterilization.

[0036] Handle assembly 14 can include one or more control mechanisms 22 for controlling distal portion 18. Such control mechanisms 22 can include, for example and without limitation, one or more sliders 22A, knobs 22B, levers, switches, buttons, electronic touchscreens, combinations thereof, or the like. Control mechanisms 22 can be configured to electronically or mechanically control various operations of distal portion 18, device 12, and / or system 10 more generally. For example and without limitation, control mechanisms 22 can be mechanically coupled to elements of distal portion 18, device 12, and / or system 10 more generally via wires, cannulae, tubes, rods, links, flex circuits, gears, cams, combinations thereof, or the like; in addition or as an alternative, control mechanisms 22 can be electronically coupled to elements of distal portion 18, device 12, and / or system 10 more generally via wired or wireless connections, motors, actuators, combinations thereof, or the like.

[0037] In example embodiments (non-limiting), one of control mechanisms 22A can be configured to control movement of one or more balloons 42, 44 of distal portion 18. Such movement control can include inflation / deflation, axial movement of the balloons toward or away from one another, axial movement of the balloons relative to handle assembly 14, combinations thereof, or the like.

[0038] One or more fluid channels, mechanical couplings, and / or electronic couplings, and / or other components can extend through portions or all of catheter tube 16. In example embodiments (non-limiting), catheter tube 16 can be configured to accommodate guidewire 20. In this manner, distal portion 18 can be delivered to a target region within the vasculature along guidewire 20.

[0039] Handle assembly 14 and / or catheter tube 16 can be configured to establish fluid connections with one or more fluid sources 28. Fluid sources 28 can include one or more containers 30 for containing one or more types of fluid, such as, for example and without limitation, saline, contrast media, combinations thereof, or the like, although any type of fluid can be used. Such connections can be made via one or more fluid ports 24.

[0040] System 10 can include one or more sensors 52. Sensors 52 can include pressure sensors, force sensors, flow rate sensors, combinations thereof, or the like. Sensors 52 can be fluidly connected between fluid source 28 and distal portion 18, which as explained further below, can be in fluid communication with the surrounding environment (e.g., the vascular environment in which distal portion 18 is operating). In this manner, as distal portion 18 is navigated to a target region within a patient's vasculature, the flow rate, resistance, pressure, or combinations thereof, of the vessel can be measured. Any number, type, and / or location of sensors 52 can be used. For example, and without limitation, sensors 52 can be mounted at distal portion 18 and connected to other elements of system 10 and / or device 12 via wired or wireless connections.

[0041] System 10 can include one or more controllers 54. Controllers 54 can be local to device 12, remote from device 12, combinations thereof, or the like. For example, and without limitation, some or all of controllers 54 can be provided on a personal electronic device and / or a server. Controllers 54 can be in electronic communication with sensors 52 and configured to receive and / or interpret data acquired from sensors 52; additionally or alternatively, controllers 54 can be in physical and / or electronic communication with control mechanism 22 and configured to receive and / or interpret data acquired from control mechanism 22. Controllers 54 can be configured to control the operation of device 12 and / or system 10 based on data acquired from sensors 52 and / or control mechanism 22.

[0042] In example embodiments, and without limitation, system 10 can include one or more displays 32. Displays 32 can be configured to provide content related to the status of device 12, fluid injection information, measured flow and / or resistance characteristics, combinations thereof, or the like. Displays 32 can function solely as a display device, and / or as an interactive user interface 22C. References herein to "displays 32" or "user interfaces 22C" refer to both functionalities, or either functionality alone. In example embodiments, and without limitation, content generated on displays 32 can be provided by controllers 52. Displays 32 can be provided on device 12 (e.g., at handle assembly 14), and / or remote from device 12 (e.g., on one or more dedicated displays and / or personal electronic devices).

[0043] The information provided on display 32 can include data readings (e.g., pressure readings, flow readings, flow rates, resistances, or combinations thereof), vascular condition information (e.g., patency, occlusion, gaps, elasticity, degree of stenosis, or combinations thereof), historical information, cumulative information, average values, highest readings, lowest readings, most common readings, median readings, bar graphs, line graphs, color-coded results (e.g., red for out-of-range, green for in-range), pass / fail indications, dials, or combinations thereof.

[0044] The information provided on display 32 can be qualitative or quantitative. Device 12 and its sensors can be calibrated according to various parameters, such as based on specific readings (e.g., in millimeters of mercury (mmHg), milliliters per minute (ml / min), wood units, pascals per meter per second (Pa / m / s), or combinations thereof). Handle assembly 14, other portions of device 12, or system 10 can include one or more speakers or other audio-generating devices for providing audible feedback related to vascular conditions. For example (and without limitation), a clicking sound can be emitted based on measured resistance; as measured resistance increases, the frequency of the clicking sound can increase. This can provide qualitative feedback to the user without requiring manual manipulation during use.

[0045] The features and manner of operation of device 12 for measuring vascular conditions will be discussed further below.

[0046] Figure 2 An exemplary embodiment of distal end 18 is shown. Distal end 18 can include one or more balloons 42, 44, and a first balloon 42 and a second balloon 44 can be provided. In the direction of catheter tube 16, first balloon 42 can be closer to handle assembly 14 relative to second balloon 44, but need not be so arranged.

[0047] Second balloon 44 can be configured to fully or substantially occlude a blood vessel upon sufficient inflation (e.g., occlusion degree > 95%). Second balloon 44 can have a relatively higher compliance compared to first balloon 42, so as to achieve full or substantial occlusion at a lower pressure. Second balloon 44 can have a length of 1 centimeter, but other dimensions can be used; and a maximum inflated diameter of 14 millimeters, but other dimensions can be used. The size and / or level of compliance of second balloon 44 used can be adjusted according to patient conditions and / or the portion of the vascular system in which device 12 is being applied.

[0048] One or more fluid channels 36 can extend through portions or all of catheter tube 16 to second balloon 44, to enable inflation and deflation of second balloon 44. As a non-limiting example, fluid channels 36 can include one or more tubes.

[0049] Additionally, for example in connection with Figure 3 As can be more clearly seen, two balloons 44, 45 can be provided to occlude a blood vessel or other vessel region, and the two balloons can be inflated separately. The length of each balloon 44, 45 can be 2 centimeters, although other dimensions can be used; any number, size, type, and / or arrangement of balloons can be used to occlude a blood vessel. Separate fluid passageways 36, 37 can be provided for each balloon 44, 45, such as to enable separate inflation / deflation, although this is not required; in other example embodiments, one or more shared fluid passageways can be used.

[0050] The first balloon 42 can be relatively less compliant than the second balloon 44, 45. In example embodiments (non-limiting), the first balloon 42 can be inflated to different diameters. In example embodiments (non-limiting), the first balloon 42 is known to inflate to different sizes at different inflation pressures, volumes, external conditions (such as ambient fluid pressure), or combinations thereof. One or more fluid passageways 48 can extend to the first balloon 42 (such as to enable separate inflation / deflation); in other example embodiments (non-limiting), one or more shared fluid passageways can be used.

[0051] One or more fluid injection passageways 38 can be provided. The fluid injection passageways 38 can extend through portions or all of the catheter tube, to a space between the first balloon 42 and the second balloon 44. The fluid injection passageways 38 can be in fluid communication with one or more ports 40 on the catheter tube 16. In this manner, fluid from one or more fluid sources 28 can be selectively injected into the blood vessel; additionally or alternatively, this can also facilitate measurement of fluid pressure within the blood vessel (such as by back pressure). Any number, size, shape, arrangement, and / or spacing of ports 40 can be used. For example (non-limiting), a plurality of such ports 40 can be distributed linearly and / or circumferentially along the catheter tube 16.

[0052] A guidewire passageway 46 can extend through portions or all of the catheter tube 16, such as to accommodate a guidewire 20, and can terminate at a distal opening 34 configured to accommodate the guidewire 20. The guidewire passageway 46 can be disposed within the fluid injection passageway 38, such as in a nested configuration, although this is not required.

[0053] In example embodiments (non-limiting), the catheter tube 16 can be configured to accommodate a second catheter tube 17 coupled to the second balloon 44. In this manner, the second balloon 44 can be moved and / or controlled independently. As a non-limiting example, the second catheter tube 17 can accommodate the passageway 46 and / or the guidewire 20, and / or one or more fluid passageways (such as the fluid passageway 36). In this manner, the second balloon 44 can pass through the first balloon 42, although this is not required.

[0054] Measurements can be made according to expected local conditions. For example, and without limitation, expected resistance levels or expected degrees of change can differ for different blood vessels. Vessel conditions can be judged manually or automatically based on absolute thresholds, percentage changes, rate changes, or combinations of the above, and the criteria can be adjusted according to the intended placement location of device 12.

[0055] Figure 4 An exemplary cross-sectional view of catheter tube 16 is shown. The size, shape, location, number, and / or arrangement of passages 36, 37, 38, 46, and / or 48 can vary. Other mechanical connections (e.g., wires, cords, cables, rods, sleeves, or combinations thereof) and / or electronic connections (e.g., wires) can be provided within catheter tube 16, in addition to or in place of some or all of passages 36, 37, 38, 46, and / or 48, to control movement of one or both balloons 42, 44.

[0056] For simplicity of illustration, some or all of the passages and / or connections in the various figures can be shown in simplified form, such as passages 36, 38, 46, 48 in Figures 2-3 and Figure 6 , and connections 40 in Figure 6 . These passages can be shown as lines (solid or dashed) to indicate their general direction, to avoid introducing unnecessary complexity that can obscure the illustration. However, those skilled in the art will appreciate that in actual applications, such passages can include one or more conduits, channels, etc., which can be provided separately and / or nested within one another, such as shown and / or described in, for example and without limitation, Figure 4 and Figure 7 .

[0057] Control mechanism 22 can be located locally at handle assembly 14 and / or device 12, or externally thereto, and can include, for example and without limitation, a valve, a pump, a motor, a nozzle, or combinations thereof, to control selective inflation and / or deflation of balloons 42, 44, 45 with inflation fluid. Inflation fluid can include one or more fluids from fluid source 28 (e.g., saline), ambient air, or combinations thereof. In addition or as an alternative, such control mechanism 22 can also be used to control selective injection of fluid through port 40 into a blood vessel.

[0058] Figure 5An exemplary method of using system 10 is shown. First proximal occlusion balloon 42 and / or distal balloons 44, 45 can be inflated to completely or substantially occlude a blood vessel (e.g., to an occlusion level of >95%). It is known that first balloon 42 and / or variable size balloon 44, 45 can inflate to different diameters under conditions such as a particular volume of inflation fluid being injected, the inflation fluid pressure being increased to a predetermined value, based on material properties, or a combination of the above factors. The volume of the region between balloons 44, 45 and balloon 42 can be known based on the distance between balloons 44, 45 and balloon 42 and / or the diameter of the blood vessel. The distance between proximal balloon 42 and distal balloons 44, 45 can be a fixed value or an adjustable value: if a fixed value, the distance is known; if an adjustable value, the distance can be electronically recorded by device 12 or manually read by a user via radiopaque markers or other visual indicators spaced along catheter tube 16. In other exemplary embodiments, the volume can be determined based at least in part on the inflated size of one or more balloons 42, 44, 45.

[0059] One or more fluids can be injected from fluid source 28 through port 40 into the blood vessel to create a fluid flow within the blood vessel having a known pressure. In exemplary embodiments (non-limiting), the fluid pressure can be set to approximate physiological pressure, such as (but not limited to) about 30-35 mm Hg, although other pressure values can be used. In this way (non-limiting example), a blood vessel region under physiological conditions can be studied. Balloons 42, 44, 45 can be adjusted to different sizes (e.g., diameters) and / or pressures by selectively inflating / deflating them.

[0060] The final flow rate and / or resistance characteristics of the fluid can be determined based on the known pressure and / or volume, and / or measured by sensor 52.

[0061] The volume of the region under study, the pressure of the fluid, and / or the volume of the fluid can be varied in a number of ways, such as by injecting additional fluid (e.g., saline), expelling some of the fluid, varying the flow rate of the fluid, and / or adjusting the position of first balloon 42 relative to second balloon 44, 45. By these operations, the changes in resistance under different conditions can be measured. The response of the tissue to these changes can indicate the level of elasticity of the blood vessel, which in turn can reflect the health or diseased state of the blood vessel. If the blood vessel is relatively more elastic, the resistance measurements will be relatively stable when the pressure and / or volume of the fluid being injected is varied, because the blood vessel can accommodate the changes in pressure and / or volume by volume adjustments, such as by expanding. If the blood vessel is relatively less elastic, the resistance measurements will vary more when the volume and / or pressure of the fluid being injected is varied, because the blood vessel has difficulty accommodating these changes by volume adjustments.

[0062] Measurements can be taken at different segments of the vessel to assess the elasticity and / or condition of the vessel. Measurements can be taken before and after treatment to assess the effectiveness of the treatment.

[0063] The controller 54 can be configured to receive data from the sensor 52 or other input data (e.g., known data, manually entered data) to determine the vessel size, occlusion characteristics (e.g., percent occlusion), vessel characteristics (e.g., degree of stenosis), or combinations thereof. The controller 54 can be configured to provide raw results and / or data interpretation results on the display 32. Such interpretation results can include (by way of non-limiting example) visual images of the occlusion and / or vessel.

[0064] Measurements can be taken at a single or multiple locations, such as along the length of the vessel to measure the overall length of the occlusion.

[0065] Veins in the human vascular system can be particularly suitable for such measurements due to their higher elasticity, but other vascular passageways can also be studied.

[0066] Additionally or alternatively, the balloons 42, 44, and / or 45 can be used to effectuate a therapeutic result. For example (by way of non-limiting example), the balloons 42, 44, and / or 45 can be used to perform angioplasty, stent implantation, drug delivery (via drug coating and / or the port 40). In this manner, the device 12 can be used to diagnose the degree of stenosis, occlusion, and / or other conditions, perform a treatment (e.g., angioplasty), and measure the resulting flow rate and / or resistance of the fluid and the condition of the vessel after treatment, all without having to remove the device from the vessel.

[0067] Contrast agents or other materials can be used to effectuate additional imaging results.

[0068] Figure 6 Another example embodiment of the distal end 18 is shown, in which one or both of the balloons 42, 44 can be slidably adjusted along the longitudinal axis of the guidewire 20 and / or the device 12. In example embodiments (by way of non-limiting example), a linkage 50 (e.g., a wire, cord, cable, sleeve, or combination thereof) can be provided to connect the first balloon 42 to one or more control devices 22 to effectuate axial movement (e.g., advancement, retraction) of the first balloon 42 along the catheter tube 16 toward the second balloon 44, or vice versa (e.g., axial retraction / advancement of the second balloon 44 toward the first balloon 42). In this manner, a reduction in volume can result in an increase in fluid pressure. Alternatively, such movement can be effected within the sheath 53; additionally or alternatively, axial movement of the second balloon 44 and / or the first balloon 42 can be effected via one or more linkages 56.

[0069] In exemplary embodiments (non-limiting), fluid flow and / or pressure can be relatively stable while the balloons 42, 44 are relatively moving, to examine a larger area of interest. For example (non-limiting), the second balloon 44 can be inflated to a size slightly smaller than the diameter of the blood vessel to be examined; fluid can be injected through the port 40 at a controlled pressure. As the second balloon 44 moves toward the first balloon 42 and encounters an occlusion, the monitored resistance can increase, as the local gap between the second balloon 44 and the occlusion's adjacent wall narrows. In this manner, the device 12 can be moved quickly over a larger area, to enable examination of a larger area, and / or to reduce the requirement for precision placement of the device 12.

[0070] Figure 7 An exemplary cross-sectional view of the catheter tube 16 is shown. Any number, size, type, and / or arrangement of channels 36, 37, 38, 46, 48 and / or connections 50, 56 can be used. For example (non-limiting), some or all of such channels 36, 37, 38, 46, 48 and / or connections 50, 56 can be in a nested arrangement and / or an adjacent arrangement.

[0071] Figure 8 An exemplary method of using the system 10 is shown. The proximal first balloon 42 can be inflated to substantially occlude the blood vessel (e.g., to an occlusion level of >95%). The distal second balloon 44 can be adjusted to different sizes (e.g., diameters) and / or pressures by selectively inflating / deflating the second balloon 44. The first balloon 42 and / or the second balloon 44 can be inflated to different diameters, given a certain volume of inflation fluid injected, a pressure of the inflation fluid increased to a predetermined value, based on material properties, or a combination of these factors. The second balloon 44, after being inflated to at least a nominal pressure, can be retracted and / or otherwise moved relative to the first balloon 42 to increase pressure and / or decrease volume. Fluid 28 can optionally, but not necessarily, be injected into the blood vessel through the port 40.

[0072] The final flow rate and / or resistance characteristics of the fluid can be determined and / or measured by the sensors 52. Changes in resistance, rates of change, or lack of change can be used to judge the health of the vessel. In an exemplary embodiment (non-limiting), as the gap between the second balloon 44 and the surrounding tissue decreases (e.g., as the fit tightens), the final pressure and / or resistance can increase, and / or the flow rate can decrease; as the gap between the second balloon 44 and the surrounding tissue increases (e.g., as the fit loosens), the final pressure and / or resistance can decrease, and / or the flow rate can increase. Such measurements can be taken at multiple locations along the vessel, under one or more flow conditions (e.g., volumetric flow, pressure, balloon 44 size, or combinations of the above), and can be used to interpret the size and / or condition of the vessel. For example (non-limiting), the size of an occlusion can be determined by measuring the amplitude of the change in vessel diameter; additionally or alternatively, areas of severe stenosis can be less elastic. In this way, the tissue response can be measured under varying conditions to determine the level of elasticity.

[0073] The controller 54 can be configured to receive data from the sensors 52 or other input data (e.g., known data, manually entered data) to determine the vessel size, occlusion characteristics (e.g., percentage of occlusion), vessel characteristics (e.g., degree of stenosis), or combinations of the above. The controller 54 can be configured to provide raw results and / or interpreted results on the display 32. Such interpreted results can include (non-limiting example) visualized images of the occlusion and / or vessel.

[0074] Contrast agents or other materials can be used to achieve additional imaging effects.

[0075] Figure 9 A non-limiting example of an exemplary visualization interface 58 provided by the system 10 is shown, which can display the vessel 64 (including the vessel wall) and / or the occlusion 68, and present various information 70.

[0076] Measurements can be taken at a single or multiple locations, such as to measure the overall length of the occlusion along the length of the vessel.

[0077] Veins in the human vasculature can be particularly well suited for such measurements due to their higher elasticity, but other vessel passageways can also be studied in this way.

[0078] Additionally or alternatively, the balloons 42, 44, and / or 45 can be used to achieve therapeutic effects. For example (non-limiting), the balloons 42, 44, and / or 45 can be used to perform angioplasty, stent implantation, drug delivery (via drug coating and / or the port 40). In this way, the device 12 can be used to diagnose the degree of stenosis, occlusion, and / or other conditions, perform a therapy (e.g., angioplasty), and measure the final flow rate and / or resistance of the fluid and the condition of the vessel after the therapy, all without the need to remove the device from the vessel.

[0079] Figures 10 to 12 The use of system 10 in an exemplary blood vessel 64 is shown. Figure 10 Occlusion balloon 42 is shown in an inflated state, substantially or completely blocking normal flow of blood or other fluid 65 in blood vessel 64 upstream of a study region, which can contain one or more blockages 68. Occlusion balloon 42 can be located upstream or upstream of a study region, and variable size balloon 44 can be located downstream or downstream of a study region. Fluid can be released through port 40 of device 12, forming a fluid flow 67 within the study region.

[0080] As shown in Figure 11 Variable size balloon 44 can be inflated to different sizes to measure changes in resistance or other characteristics of the injected fluid flow 67; additionally or alternatively, the state of injected fluid flow 67 can be changed to measure changes in resistance or other characteristics. Distal balloon 44 can be inflated to a state that fully or partially occludes blood vessel 64.

[0081] As shown in Figure 12 First balloon 42 can include one or more skirts 72. Skirts 72 can extend from the front or back of first balloon 42, and can be caused to conform to the inner wall of blood vessel 64 by movement of first balloon 42 and / or the natural flow of fluid 65 within blood vessel 64. This can help to further occlude blood vessel 64, for example to ensure a good seal with the inner wall of blood vessel 64; additionally or alternatively, skirts 72 can fully or partially seal adjacent branch blood vessels 64, for example to prevent fluid 65 from these branch blood vessels 64 from flowing into or out of the study region. This design can be particularly useful when the study region and / or blockages 68 are near one or more branch blood vessels 64; additionally or alternatively, skirts 72 can smooth or block abnormal sites within blood vessel 64 that are not being studied.

[0082] Skirts 72 can allow balloons 42, 44 to operate at relatively lower pressures by providing additional sealing and preventing natural fluid flow 65 from entering the study region.

[0083] Although the present disclosure is sometimes described herein with reference to veins as examples, the present disclosure can also be applicable to arterial or other blood vessel related applications as further non-limiting examples.

[0084] Any embodiment of the application can include any of the features of other embodiments of the application. The example embodiments disclosed herein are not intended to be exhaustive or to limit the scope of the application to the precise embodiments described. These example embodiments were chosen and described so that others skilled in the art might understand and appreciate various principles and interrelationships between elements of the application. Having described and illustrated the principles of the present application in reference to a number of example embodiments, it will be recognized that the example embodiments can be modified, altered, and / or adapted in various ways, and as such each embodiment should not be interpreted in a restrictive sense. Rather, the application should be understood to encompass any presently known or later developed techniques that meet the objectives of the application.

[0085] Certain operations described herein can be performed by one or more electronic devices. Each electronic device can include one or more processors, electronic storage devices, executable software instructions, or combinations of the above components, configured to perform the operations described herein. The electronic devices can be general purpose computers or specialized computing devices, such as personal computers, smartphones, tablet computers, databases, servers, etc. Electronic connections and transmissions described herein can be implemented through wired or wireless means. The computerized hardware, software, components, systems, steps, methods, and / or processes described herein can be used to improve the speed of their own operation. Electronic devices, including but not limited to electronic storage devices, databases, controllers, etc., can include and / or be configured to store only non-transitory signals.

Claims

1. An intravascular device for interpreting a blood vessel condition, wherein, The intravascular device comprises: a catheter tube; a first selectively inflatable balloon disposed at a distal portion of the catheter tube; a second selectively inflatable balloon disposed along the catheter tube distally of and spaced apart from the first balloon; and one or more ports disposed along the catheter tube between the first balloon and the second balloon; wherein the spacing of the first balloon relative to the second balloon is adjustable.

2. The intravascular device of claim 1, wherein, Further comprising: an additional catheter tube, wherein the first balloon is fixed to the additional catheter tube, the second balloon is fixed to the catheter tube, and the catheter tube is slidable within the additional catheter tube to adjust the spacing of the first balloon relative to the second balloon.

3. The intravascular device of claim 2, wherein, Further comprising: a handle assembly, wherein the catheter tube extends at least to the handle assembly, and the additional catheter tube is fixed to the handle assembly.

4. The intravascular device of claim 1, wherein, Further comprising: a handle assembly, wherein the catheter tube extends at least to the handle assembly; a connection extending within the catheter tube from the handle assembly to the second balloon; and a control device disposed at the handle assembly for controlling the connection to adjust the spacing of the first balloon relative to the second balloon. Further comprising:

5. The intravascular device of claim 1, wherein, a handle assembly; and a control device disposed at the handle assembly for controlling delivery of fluid from a proximal portion of the catheter tube or a fluid reservoir in fluid communication with the proximal portion of the catheter tube through the one or more ports to a patient's vasculature. Further comprising: one or more additional control devices associated with the handle assembly for controlling delivery of inflation fluid from one or more additional fluid reservoirs located at a proximal portion of the catheter tube or in fluid communication with the proximal portion of the catheter tube to the first balloon and the second balloon such that the first balloon and the second balloon can be inflated independently; and 6. The intravascular device of claim 5, wherein, one or more tubular passageways for delivering the fluid extending within or along the catheter tube and in fluid communication with the first balloon and the second balloon to effect inflation of the first balloon and the second balloon as described. Further comprising: one or more sensors located at or in fluid communication with the one or more ports and / or located within or in fluid communication with an interior of the catheter tube for measuring changes in one or more characteristics of fluid between the first balloon and the second balloon.

7. The intravascular device of claim 1, wherein, Further comprising: a controller in electronic communication with the one or more sensors, wherein the controller comprises one or more electronic storage devices containing software instructions that, when executed, configure one or more processors to:

8. The intravascular device of claim 7, wherein, receive a first reading from the one or more sensors at a first point in time when the first balloon is at a first spacing along the catheter tube from the second balloon and fluid is being injected from the one or more ports; and receive a second reading from the one or more sensors at a second point in time when the first balloon is at a second spacing along the catheter tube from the second balloon and fluid is being injected from the one or more ports. ​ ​ receiving a second reading from the one or more sensors at a second time point, at which the first balloon and the second balloon are at a second spacing, and the second spacing is less than the first spacing.

9. The intravascular device of claim 7, wherein, Further comprising: a controller in electronic communication with the one or more sensors, wherein the controller comprises one or more electronic storage devices containing software instructions that, when executed, configure one or more processors to: receive a first reading from the one or more sensors at a first time point, at which the fluid injected from the one or more ports has a controlled pressure and / or flow rate; receive a second reading from the one or more sensors at a second time point, at which the controlled pressure and / or flow of the fluid is being changed or has been changed in a known manner.

10. The intravascular device of claim 7, wherein, Further comprising: a controller in electronic communication with the one or more sensors, wherein the controller comprises one or more electronic storage devices containing software instructions that, when executed, configure one or more processors to: receive data from the one or more sensors at a first time point, at which fluid is being injected from the one or more ports; receive data from the one or more sensors at a second time point, at which at least one of the following is being adjusted or has been adjusted: fluid flow from the one or more ports, inflation level of the second balloon, and spacing between the first balloon and the second balloon.

11. The intravascular device of claim 7, wherein: the one or more sensors comprise at least one of: a pressure sensor and a flow rate sensor.

12. The intravascular device of any one of claims 7 to 11, wherein: the controller contains additional software instructions in the one or more electronic storage devices that, when executed, further configure one or more processors to: determine a flow resistance at the first time point and the second time point; and determine a condition of the blood vessel based at least in part on a change in flow resistance between the first time point and the second time point.

13. The intravascular device of claim 1, wherein, Further comprising: a skirt extending from at least one of the first side and the second side of the first balloon.

14. A method of interpreting a condition of a blood vessel using an intravascular device, the method comprising: introducing a distal portion of the intravascular device into a blood vessel system of a patient, wherein the intravascular device comprises: a catheter tube; a first balloon that is selectively inflatable, disposed at a distal portion of the catheter tube; a second balloon that is selectively inflatable, disposed along the catheter tube distally of the first balloon and spaced apart from the first balloon; and one or more ports spaced apart along the catheter tube between the first balloon and the second balloon; wherein a spacing of the first balloon relative to the second balloon is adjustable; inflating the first balloon to at least contact an inner surface of the blood vessel; inflating the second balloon at least partially; injecting a fluid through the one or more ports into the blood vessel system of the patient; and receiving data from the one or more sensors at a first time point, at which fluid is being injected from the one or more ports; receiving data from the one or more sensors at a second time point, at which at least one of the following is being adjusted or has been adjusted: fluid flow from the one or more ports, inflation level of the second balloon, and spacing between the first balloon and the second balloon. One or more characteristics of the fluid are measured at a plurality of time points by one or more sensors associated with the intravascular device.

15. The method of claim 14, wherein, Further comprising the steps of: moving the second balloon relative to the first balloon to reduce the spacing between the first balloon and the second balloon, wherein the plurality of time points includes at least one time point before the second balloon is moved relative to the first balloon and at least one time point after the second balloon is moved relative to the first balloon.

16. The method of claim 14, further comprising the steps of: altering at least one characteristic of the fluid in a known manner, wherein the plurality of time points includes at least one time point before the at least one characteristic of the fluid is altered and at least one time point after the at least one characteristic of the fluid is altered.

17. The method of claim 16, wherein: the at least one characteristic of the fluid includes pressure or flow rate; and at least between the first time point and the second time point, the other of the pressure or flow rate of the fluid remains constant.

18. The method of claim 14, wherein, Further comprising: adjusting the inflation level of the second balloon, wherein the plurality of time points includes at least one time point before the inflation level of the second balloon is adjusted and at least one time point after the inflation level of the second balloon is adjusted, and at least between the first time point and the second time point, at least one of the pressure and flow rate of the controlled fluid remains constant.

19. The method of any one of claims 14 to 18, wherein, Further comprising the steps of: electronically automatically deriving, by executing software instructions stored in one or more non-transitory electronic storage devices, and by one or more processors operating in accordance with the software instructions: determining a flow resistance at each of the plurality of time points based at least in part on data received from the one or more sensors at the plurality of time points; and interpreting a condition of the blood vessel based on changes in the flow resistance between the plurality of time points.

20. A system for interpreting a condition of a blood vessel by measuring flow resistance, the system comprising: an intravascular device comprising: a handle assembly including a control device; a first catheter tube extending from and fixed relative to the handle assembly; a selectively inflatable first balloon disposed at a distal end of the first catheter tube; a second catheter tube positioned within the first catheter tube with a distal end extending beyond the distal end of the first catheter tube and the first balloon; a selectively inflatable second balloon disposed at a distal end of the second catheter tube, wherein the second catheter tube is slidable relative to the first catheter tube by operation of the first control device to adjust a spacing between the first balloon and the second balloon; and a plurality of ports spaced along the catheter tubes between the first balloon and the second balloon, wherein the ports are in fluid communication with a fluid reservoir and an interior of the catheter tubes, and operation of a second control device is used to adjust a flow of fluid from the fluid reservoir to the ports; wherein operation of a third control device is used to adjust an inflation level of the first balloon. wherein the fourth control device is operated to adjust an inflation level of the second balloon; a sensor in fluid communication with the port to measure a change in a characteristic of the fluid, the characteristic including pressure and flow rate; and a controller including one or more non-transitory electronic storage devices containing software instructions that, when executed, configure one or more processors to: receive readings from the sensor at a plurality of time points at which the controlled fluid having at least one of a controlled pressure and a controlled flow rate is provided through the port, wherein at least a first time point is when the first balloon is inflated and at a first spacing from the second balloon also in an inflated state, and at least a second time point is when the first balloon is inflated and at a second spacing from the second balloon also in an inflated state, and the second spacing is less than the first spacing; determine a resistance of the controlled fluid based at least in part on the readings at the first time point and the second time point; and determine a condition of the blood vessel based at least in part on a change in the resistance between the first time point and the second time point.

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