Wireless resonant circuit and variable inductance vascular monitoring implant and anchoring structure thereof

Abstract

Wireless vascular monitoring devices, systems, methods, and techniques based on variable inductance and resonant circuits are disclosed, including anchoring structures specifically configured for them. These wireless vascular monitoring devices, systems, methods, and techniques based on variable inductance and resonant circuits can be used to assist healthcare professionals in predicting, preventing, and diagnosing a variety of heart-related health conditions and other health conditions.

Description

[0001] open field

[0002] This invention generally relates to the field of vascular monitoring. In particular, the invention relates to wireless vascular monitoring implants and their anchoring structures. More specifically, the embodiments disclosed herein relate to fluid volume sensing in the inferior vena cava (IVC) using wireless, remotely or automatically actuated implants for monitoring or managing blood volume.

[0003] background

[0004] Others have attempted to develop vascular monitoring devices and technologies, including those for monitoring arterial or venous pressure or vascular lumen size. However, many of these existing systems are catheter-based (not wireless) and therefore limited to limited timeframes in clinical settings, potentially introducing risks associated with prolonged catheter insertion. For wireless solutions, the complexities of deployment, fixation, and the interrelationships between these factors and detection and communication, at best, result in inconsistent outcomes with these previously developed devices and technologies.

[0005] Existing wireless systems focus on pressure measurement, which is less responsive to the patient's fluid state in the IVC compared to IVC sizing. However, systems designed to measure vessel size also have several drawbacks in IVC monitoring. Impedance-based systems require electrodes to be positioned specifically relative to the width of the vessel. Such devices present particular difficulties when attempting to monitor IVC size because the IVC does not expand and contract symmetrically like most other vessels that may need monitoring. Precise positioning of these position-dependent sensors remains an unresolved problem. IVC monitoring presents additional challenges due to IVC physiology. The IVC wall is relatively compliant compared to other vessels and is therefore more susceptible to distortion due to the forces exerted by the implant to maintain its position within the vessel. Therefore, devices that work satisfactorily in other vessels may not be able to provide accurate monitoring in the IVC due to the distortion caused by the forces exerted by the implant on the IVC wall. Therefore, new developments in this area are anticipated to provide physicians and patients with reliable and affordable wireless vascular monitoring, particularly in the critical area of ​​heart failure monitoring.

[0006] Public Overview

[0007] The embodiments disclosed herein include wireless vascular monitoring devices, circuits, methods, and related technologies for assisting healthcare professionals in predicting, preventing, and diagnosing various conditions, indices of which may include vascular fluid state. Using the disclosed embodiments, metrics, including, for example, relative fluid state, fluid responsiveness, fluid tolerance, or heart rate, can be accurately estimated.

[0008] In one implementation, this disclosure relates to a wireless vascular monitoring implant that is adapted to be deployed and implanted in a patient's vascular system and positioned at a monitoring location in the lumen of the blood vessel in a manner that contacts the lumen wall. The implant includes an elastic sensor structure configured to expand and contract in size with natural movement of the lumen wall; wherein the electrical properties of the elastic sensor structure vary in a known relationship with its dimensional expansion and contraction; and the elastic sensor structure generates a wireless signal indicative of the electrical properties, which is wirelessly readable outside the lumen to determine the size of the lumen; the elastic sensor structure is configured and dimensionally designed to engage the lumen wall and to be substantially permanently implanted on or within the lumen wall; the elastic sensor structure has a variable inductance associated with its dimensional expansion and contraction in at least one dimension; and when powered by a power source for the structure, the elastic sensor structure generates a signal wirelessly readable outside the patient indicating a value in at least one dimension, thereby allowing the size of the lumen to be determined; wherein the elastic sensor structure includes a coil configured to engage with at least two opposing points on the lumen wall, the inductance of which varies based on the distance between the two opposing points on the coil. The distance between the relative points corresponds to the distance between points on the lumen wall; wherein the coil is rotationally symmetric about the longitudinal axis; wherein the elastic sensor configuration is configured to expand and contract along substantially any transverse axis of the blood vessel with the lumen wall to cause a change in variable inductance; wherein the elastic sensor configuration further includes a frame having at least one elastic portion formed with at least two points configured to be positioned relative to each other so as to engage opposite surfaces of the blood vessel lumen wall when the sensor configuration is positioned in a monitoring position in a manner that contacts the lumen wall; wherein the coil is formed on the frame by at least one wire arranged around the frame to form a plurality of adjacent strands around the frame; wherein the elastic sensor configuration includes a resonant circuit whose resonant frequency varies with the variable inductance, and the signal is related to the resonant frequency; wherein the coil includes a resonant circuit having an inductance and a capacitance defining a resonant frequency, wherein the resonant frequency varies based on the distance between the at least two points; and the coil is configured to be excited by a magnetic field directed at the coil from outside the patient.

[0009] These and other aspects and features of the non-limiting embodiments of the present disclosure will be apparent to those skilled in the art from the following description of specific non-limiting embodiments of the invention, taken in conjunction with the accompanying drawings. Brief description of the attached diagram

[0011] For the purpose of illustrating this disclosure, the accompanying drawings illustrate aspects of one or more embodiments of the disclosure. However, it should be understood that the disclosure is not limited to the precise arrangements and means shown in the drawings, wherein:

[0012] Figure 1 An embodiment of the wireless resonant circuit-based vascular monitoring (“RC-WVM”) system of this disclosure is schematically depicted;

[0013] Figure 1A A portion of an alternative embodiment of the RC-WVM system of this disclosure is schematically depicted;

[0014] Figure 2 and Figure 2A An alternative embodiment of an RC-WVM implant manufactured in accordance with the teachings of this disclosure is illustrated;

[0015] Figure 2B yes Figure 2 A schematic detailed view of the capacitor segment of the RC-WVM implant;

[0016] Figure 3 , Figure 3A , Figure 3B , Figure 3C and Figure 3D The diagram shows... Figure 1 An embodiment of a strip antenna schematically depicted in the system;

[0017] Figure 3E The orientation of the antenna strip relative to the implanted RC-WVM implant and the resulting magnetic field are schematically depicted.

[0018] Figure 4 It is a block diagram illustrating an embodiment of the system's electronic components;

[0019] Figure 5A and Figure 5B The diagram illustrates the waveform of a fixed-frequency RF burst excitation signal.

[0020] Figure 6A and Figure 6B The diagram illustrates the waveform of the swept-frequency RF burst excitation signal;

[0021] Figure 7A and Figure 7B The diagram illustrates the waveform of a multi-frequency RF burst excitation signal;

[0022] Figure 8 The diagram illustrates waveform pulse shaping;

[0023] Figure 9 Aspects of an embodiment of a delivery system for an RC-WVM implant as disclosed herein are schematically illustrated;

[0024] Figure 9A The distal end of an alternative embodiment of a delivery system for an alternative RC-WVM implant with an attachment anchoring frame as disclosed herein is schematically illustrated.

[0025] Figure 10A , Figure 10B , Figure 10C , Figure 10D and Figure 10E The diagram illustrates the use of a prototype system and, for example... Figure 1 and Figure 2 Signals obtained from preclinical experiments of the RC-WVM implant shown;

[0026] Figure 11A , Figure 11B and Figure 11C An alternative RC-WVM implant embodiment according to the teachings of this disclosure is illustrated;

[0027] Figure 12 The illustration shows, for example Figure 11A Assembly of the alternative RC-WVM implant embodiment shown in -C;

[0028] Figure 13 This is a detailed view of the anchoring structure that is installed on the implant before encapsulation;

[0029] Figure 14A , Figure 14B and Figure 14C The illustration shows an alternative anchoring structure for use with RC-WVM implant embodiments;

[0030] Figure 15A and Figure 15B An alternative embodiment of a strip antenna for use with the RC-WVM implant and system as described herein is illustrated;

[0031] Figure 16A and Figure 16B The illustration shows a recapture feature that facilitates the localization and repositioning of the RC-WVM implant during placement using the delivery catheter disclosed herein.

[0032] Figure 17 This is a perspective view of an alternative RC-WVM implant embodiment with an attachment anchoring frame and axial anchoring barbs;

[0033] Figure 18 For example Figure 17 A perspective view of the anchoring frame shown;

[0034] Figure 19 This is a detailed diagram showing the support section where the anchoring frame is attached to the RC-WVM implant;

[0035] Figure 20 This is a detailed diagram showing the gap in the anchoring frame that prevents the magnetic field from coupling with the anchoring frame;

[0036] Figure 21The illustration shows another alternative embodiment in which the anchoring frame is positioned at both ends of the RC-WVM implant;

[0037] Figure 22A , Figure 22B and Figure 22C Another embodiment of the anchoring frame is illustrated, wherein the anchoring barbs are oriented parallel to the anchoring frame support.

[0038] Figure 23A , Figure 23B and Figure 23C Another embodiment of the anchoring frame is illustrated, wherein the anchoring barbs are oriented in the flow direction within the blood vessel in which the RC-WVM is implanted;

[0039] Figure 24A and Figure 24B Another embodiment of the anchoring frame is illustrated, wherein the anchoring barb is positioned at the top of the anchoring frame;

[0040] Figure 25A The diagram illustrates a fixed anchoring frame, wherein adjacent anchoring barbs are on the same side of the frame supports; and Figure 25B An alternative with dual anchors at each anchoring location is shown;

[0041] Figure 26A , Figure 26B , Figure 26C , Figure 26D , Figure 26E , Figure 26F , Figure 26G and Figure 26H Each illustration depicts an alternative embodiment of the anchoring barb;

[0042] Figure 27 This is a schematic cross-sectional view showing the non-conductive connection between two anchoring frame components;

[0043] Figure 28 A perspective view of another alternative anchoring frame embodiment is shown; and

[0044] Figure 29A , Figure 29B , Figure 29C and Figure 29D Different alternative embodiments of the anchoring frame attachment arm are shown.

[0045] Detailed description

[0046] This disclosure relates to wireless resonant circuit-based vascular monitoring (“RC-WVM”) implants, systems, methods, and software, including excitation feedback monitoring (“EFM”) circuitry that can be used to excite the RC-WVM implant with an excitation signal and receive characteristic feedback signals generated by the RC-WVM implant. By automatically or manually analyzing the feedback generated by the RC-WVM implant, healthcare professionals can help predict, prevent, and diagnose various cardiac, renal, or vascular-related health conditions. For example, feedback generated by the RC-WVM implant at a specific time can be compared with feedback generated by the RC-WVM implant at other times and / or with feedback generated by a baseline RC-WVM implant to understand vascular geometry and thus estimate relative fluid status, fluid responsiveness, fluid tolerance, heart rate, respiratory rate, and / or other metrics. One or more of these estimates can be generated automatically or manually to monitor the patient’s condition and provide feedback to healthcare professionals and / or the patient in the event of any anomalies or relevant trends.

[0047] System Overview

[0048] The unique physiology of the IVC presents unique challenges in attempting to detect and interpret changes in IVC size caused by variations in a patient's fluid state. For example, the IVC walls in a typical monitoring area (i.e., between the hepatic and renal veins) are relatively compliant compared to other vessels, meaning that changes in vascular volume can cause different changes in the relative distance between the anterior and posterior walls compared to the medial and lateral walls. Therefore, typically, changes in fluid volume will cause contradictory changes in vascular geometry and movement; that is, as blood volume decreases, the IVC tends to shrink and collapse with respiration, while as blood volume increases, the IVC tends to enlarge and collapse less with respiration. The systems and implants disclosed herein are uniquely configured to compensate for and interpret such contradictory changes.

[0049] like Figure 1 As shown, the system 10 according to this disclosure typically includes an RC-WVM implant 12 configured for placement in a patient's IVC, a control system 14, an antenna module 16, and one or more remote systems 18 communicating with the control and communication module via one or more data links 26, such as processing systems, user interfaces / displays, data storage, etc., which may be wired or remote / wireless data links. In many embodiments, the remote system 18 may include a computing device and a user interface serving as an external interface device, such as a laptop computer, tablet computer, or smartphone.

[0050] The RC-WVM implant 12 typically includes a variable inductor, a constant capacitance, and a resonant LC circuit formed as an elastically collapsible coil structure that moves with the IVC wall as the IVC wall expands and contracts due to changes in fluid volume when positioned at a monitoring location within the patient's IVC. The variable inductance is provided by the coil structure of the implant such that the inductance changes as the size of the coil changes with the movement of the IVC wall. The capacitive element of the circuit can be provided by discrete capacitors or by the inherent capacitance specifically designed into the implant structure itself. Embodiments of the RC-WVM implant 12 may also be provided with anchoring and isolation devices inherently designed into the implant structure, or have unique additional such structures to ensure that the implant is securely and properly positioned in the IVC without excessively distorting the vessel wall, thereby distorting or otherwise negatively impacting the measurements determined by the implant. Typically, the RC-WVM implant 12 is configured to at least substantially permanently implant itself into the vessel wall in which it is placed during deployment and does not require physical connection (for communication, power, or other means) to any device outside the patient's body after implantation. As used herein, "substantially permanently implanted" means that, under normal use, the implant will remain embedded in the vessel wall for its entire useful life and may integrate into the vessel wall to varying degrees due to tissue inward growth, but can be intentionally removed by endovascular interventional or surgical removal procedures specifically designed for implant removal as indicated in medicine. Details of alternative embodiments of implant 12 (e.g.) Figure 2 , Figure 2A and Figure 11A -C (as shown) is provided below. In particular, it should be noted that any of the alternative RC-WVM implants described herein can be used in the alternative system 10 described herein without further modification to the system, unless the modification can be determined.

[0051] The control system 14 includes functional modules (typically including EFM circuitry and designated as module 20) for signal generation, signal processing, and power supply, and a communication module 22. Communication module 22 facilitates communication with and data transmission to various remote systems 18 via data link 26 and optionally via other local area-based or cloud-based networks 28. Details of exemplary embodiments of the control system 14, modules 20 and 22, and alternative elements to the EFM circuitry are described below and in [the relevant section]. Figure 4 The diagram is shown below. After the signal received from the RC-WVM implant 12 is analyzed following excitation by the transmitting coil of the EFM circuit, the results can be transmitted manually or automatically via remote system 18 to the patient, caregiver, medical professional, health insurance company, and / or any other expectant and authorized party in any suitable manner (e.g., verbally, by printing out a report, by sending a text message or email, or otherwise).

[0052] Antenna module 16 is connected to control system 14 via power and communication link 24, which can be wired or wireless. Based on signals provided by the EFM circuitry of control system 14, antenna module 16 generates a properly shaped and oriented magnetic field around RC-WVM implant 12. The magnetic field excites the LC circuitry of RC-WVM implant 12, causing it to generate a "ring-back" signal indicating the current inductance value. Because the inductance value depends on the geometry of the implant, which, as described above, changes based on the size of the IVC in response to changes in fluid state, heart rate, etc., the ring-back signal can be interpreted by control system 14 to provide information about the geometry of the IVC and the associated fluid state. Therefore, antenna module 16 also provides a receiving function / antenna and a transmitting function / antenna. In some embodiments, the transmitting and receiving functions are performed by a single antenna; in other embodiments, each function is performed by a separate antenna. Antenna module 16 in Figure 1 The image is schematically depicted as an antenna strip, and this embodiment is described in more detail below. Figure 3A -D is shown.

[0053] Figure 1A An alternative embodiment of the antenna module 16 as antenna plate 16a is illustrated, wherein the transmitting coil 32 and the receiving coil 34 are disposed in a plate or mattress 36, and the patient lies with his / her back on the plate or mattress 36, wherein the RC-WVM implant 12 (implanted in the IVC) is positioned above the coils 32, 34. Figure 1A The antenna module 16 shown is functionally equivalent to other alternative antenna modules disclosed herein; as described above, antenna module 16 is connected to control system 14 via power and communication link 24. Another alternative embodiment of the strip antenna module is... Figure 15A and Figure 15B The planar antenna module is shown in the diagram. It can also be configured in wearable configurations, such as where the antenna coil is integrated into wearable clothing, such as a backpack or vest. Antenna module 16 may also include a coil adapted to be directly attached to the patient's skin via tape, glue, or other means, for example, above the abdomen or back, or the coil may be adapted to be integrated into furniture, such as a chair back. As those skilled in the art will understand, various embodiments of antenna module 16 as described herein can be used with other devices without additional changes to the system or antenna module. Figure 1 The system 10 shown is used together, except as expressly indicated herein.

[0054] Variable inductance LC circuits generate resonant frequencies that vary with inductance. When an implant is securely fixed at a known monitoring location within an IVC, changes in the geometry or dimensions of the IVC cause changes in the construction of the variable inductor, which in turn cause changes in the circuit's resonant frequency. These changes in resonant frequency can be correlated with changes in vascular geometry or dimensions via an RC-WVM control and communication system. Therefore, not only should the implant be securely positioned at the monitoring location, but at least the variable coil / inductor portion of the implant should also have a predetermined elasticity and geometry. Thus, typically, the variable inductor is specifically configured to change shape and inductance proportionally to changes in vascular geometry. In some embodiments, anchoring and isolation devices will include suitably selected and configured shapes and compliance within the sensor coil structure of the implant to move with the vessel wall while maintaining positioning. Such embodiments may or may not include additional anchoring features, as discussed in more detail below. Alternatively, the anchoring and isolation device may include a separate structure spaced apart from and / or mechanically isolated from the variable inductor coil structure, such that the anchoring function is physically and / or functionally separated from the measurement / monitoring function, and that any twisting or constraint on the blood vessel caused by the anchor is sufficiently distanced from and / or isolated from the variable inductor to avoid unduly affecting the measurement.

[0055] The RC-WVM implant 12, acting as a variable inductor, is configured to be remotely excited by an electric field delivered by one or more transmitting coils within an antenna module positioned outside the patient's body. Upon excitation, the LC circuit generates a resonant frequency, which is then detected by one or more receiving coils of the antenna module. Because the resonant frequency depends on the inductance of the variable inductor, changes in the geometry or size of the inductor caused by variations in the vessel wall geometry or size result in changes in the resonant frequency. The detected resonant frequency is then analyzed by the RC-WVM control and communication system to determine changes in vessel geometry or size. The information derived from the detected resonant frequency is processed using various signal processing techniques described herein and can be transmitted to various remote devices (such as healthcare provider systems or patient systems) to provide status or, where appropriate, alerts or treatment modifications. To facilitate the measurement of the detected resonant frequency, it is desirable to provide a design with a relatively high Q factor, i.e., a resonant circuit configuration that maintains signal / energy for a relatively long period of time, particularly when operating at lower frequencies. For example, in order to realize the advantages of using Litz lines as further described herein, it is desirable to operate in a resonant frequency range below 5 MHz, typically between about 1 MHz and 3 MHz, in which case it is desirable for the resonant circuit configuration to have a Q factor of at least about 50 or greater.

[0056] Example of a complete system embodiment

[0057] See below for reference Figure 2-8 Details of one possible embodiment of the complete exemplary system 10 are discussed. Subsequently, details of other alternative embodiments of the system components are described. However, it should be understood that the exemplary system is not limited to the use of... Figure 1-8 The specific elements or components shown are as indicated, and any alternative components subsequently described may be replaced without changing the entire system, unless otherwise specified.

[0058] Figure 2 An example of an RC-WVM implant 12 according to this disclosure that can be used in exemplary system 10 is illustrated. Figure 2 The enlarged detail within the box represents the cross-sectional view shown. (Note that in the cross-sectional view, the ends of the very fine lines may not be clearly visible due to their small size). Typically, the RC-WVM implant 12 includes a resilient sensor construction that typically comprises an induction coil formed around an open center that allows blood to flow substantially unimpeded through it, wherein the inductance of the induction coil changes with the construction geometry due to forces applied thereto. In this example, the implant 12a is formed as a resilient concentric zigzag or linked “Z” structure with a series of support sections 38 joined at their ends by rounded crown sections 40 forming acute angles. The resulting structure can also be perceived as sinusoidal in appearance. This structure can be formed by winding the wire 42 around a frame or core 44. In this alternative, the RC-WVM implant 12a has a shaped 0.010” nickel-titanium alloy wire frame 44, with 300 individually insulated Kinlitz wires 42, each 0.04 mm in diameter, wound in a single loop around the nickel-titanium alloy wire frame. In the case of single-loop winding, as in... Figure 2 As can be seen in the cross-sectional view, the strands of line 42 appear substantially parallel to the frame at any given point. The individual insulators on the Litz line 42 can be formed as a biocompatible polyurethane coating. Also in this particular example, the discrete capacitor 46 is provided with a capacitance of approximately 47 nF (nanofarads); however, the capacitance can range from approximately 180 picofarads to approximately 10 microfarads to cover all possible permissible frequency bands of the RC-WVM implant 12 (from approximately 148.5 kHz to approximately 37.5 MHz).

[0059] In an alternative, instead of arranging a relatively large number of strands in a single loop, a relatively small number of strands (e.g., in the range of about 10-20 strands, or more specifically about 15 strands) can be arranged in a relatively large number of loops (e.g., in the range of about 15-25 loops, or more specifically about 20 loops). In this alternative embodiment, discrete capacitor elements are replaced with the inherent coil capacitance formed based on the space between the parallel strands.

[0060] In another alternative embodiment, the implant 12a is configured to ensure that the support segment 38 is a straight support segment between the coronary segments 40. A straight support segment offers the advantage that the support segment remains in contact with the vessel wall along its entire length, regardless of the size of the vessel in which it is deployed. When the sensor construction frame is formed, for example, by laser cutting from a nickel-titanium alloy tube, the straight configuration of the support segment can be achieved by shaping it to maintain the desired straight configuration.

[0061] Also refer to Figure 2B A Litz wire 42 is formed around a shaped nickel-titanium alloy frame 44. The two ends of the Litz wire 42, possibly covered with a layer of PET heat-shrink tubing 60, are connected together with capacitors 46 to form a loop circuit. The capacitors 46 include capacitor terminals 52 connected to the Litz wire 42 via solder connections 54 to gold wire contacts 56. The gold wire contacts 56 are formed by removing (or burning off) short sections of individual insulators from the ends of the Litz wire 42 and joining these ends to form solid contacts, which can then be connected to the capacitor terminals 52 via solder connections 54. The capacitors, capacitor terminals, and gold wire contacts are encapsulated in a suitable biocompatible insulating material 58 (such as a reflow polymer or epoxy). In an alternative embodiment, the entire structure can then be covered with a layer of PET heat-shrink insulator 60. Alternatively, if it is determined that a short circuit should not be created through the frame, gaps can be provided within the frame at the capacitors or elsewhere.

[0062] like Figure 2 As shown, the RC-WVM implant 12a may also optionally be provided with an anchor 48 to help prevent implant migration after placement in the IVC. The anchor 48 may also be formed from a nickel-titanium alloy laser-cut segment or shaping line and incorporated into each support segment 38. Barbs 50 extend outward at the ends of the anchor 48 to engage the IVC wall. In one embodiment, the anchor 48 is bidirectional in both head and tail directions; in other embodiments, the anchor may be in one direction, a mixture of both directions, or perpendicular to the blood vessel.

[0063] The overall structure of the RC-WVM implant 12 strikes a balance between electrical and mechanical requirements. For example, the ideal electrical sensor is positioned as close as possible to the solenoid, with the strut length being as short as possible and ideally zero, while mechanical considerations for deployment and stability dictate that the implant strut length be at least as long as the diameter of the blood vessel in which the strut will be deployed, to avoid misalignment and maintain stability. The dimensions of the components of the RC-WVM implant 12a are determined by… Figure 2 The letters AF are used to identify these dimensions, and examples of typical values ​​suitable for a range of patient anatomy are provided below in Table I. Generally, based on the teachings herein, those skilled in the art will recognize that the uncompressed free-state (overall) diameter of the RC-WVM implant 12 should not significantly exceed the maximum expected fully extended IVC diameter of the patient to whom the RC-WVM implant will be used. The height of the RC-WVM implant should generally be selected to balance implant stability at the monitoring location with geometry / flexibility / elasticity, thereby providing adaptation within the intended area of ​​the IVC without affecting the ability of the hepatic or renal veins in most individuals, which could impair sensory data generated by the implant. Among other factors, height and stability considerations will be influenced by the specific RC-WVM implant design configuration and whether significant anchoring features are included. Therefore, as those skilled in the art will understand, the main design consideration of the RC-WVM implant 12 according to this disclosure is to provide a structure that forms a variable inductance LC circuit capable of performing the measurement or monitoring functions described herein, and is configured to securely anchor the structure within the IVC without twisting the IVC wall by providing sufficient but relatively low radial force to the IVC wall.

[0064]

[0065] Another alternative structure for the RC-WVM implant 12 is as follows: Figure 2A The illustration shows the RC-WVM implant 12b. Figure 2AThe enlarged details within the frame again represent the cross-sectional view taken as indicated. In this embodiment, the overall structure of implant 12b is similar to that of implant 12a, formed on a frame having a straight support section 38 and a curved crown section 40. In this embodiment, the discrete capacitors of the previous embodiment are replaced by distributed capacitance between several bundles of wire strands. Multiple strands (e.g., approximately fifteen strands) of wire 64 are placed parallel to each other and twisted into bundles. The bundle is then wound multiple times around the entire circumference 68 of the wire frame 66 (which can be, for example, a nickel-titanium alloy wire with a diameter of 0.010”), resulting in a multi-turn parallel strand bundle. The insulator between the bundles results in a distributed capacitance that causes the RC-WVM to resonate as before. The overall dimensions are similar and can be approximated as shown in Table I. The outer insulation layer or coating 60 can be applied as previously described or using an impregnation or spraying process. In this case, in the absence of discrete capacitors, the LC circuit is instead generated by tuning the inherent capacitance of the structure via the selection of the material and length / configuration of the strands. In this case, 20 turns of 15 strands of wire together with the silicone outer insulation layer 60 are used to achieve the capacitance inherent in the implant 12b in the range of approximately 40-50 nF.

[0066] Unlike implant 12a, the frame 66 of implant 12b is not continuous to avoid completing an electrical loop within the implant, as this would negatively impact performance. Any overlapping ends of the frame 66 are spaced apart by an insulating material such as heat-shrink tubing, insulating epoxy, or reflow polymer. RC-WVM implant 12b (may include or may not include anchors). Alternatively, the implant is configured to be compliant / resilient to allow it to move with changes in the geometry or size of the IVC wall, while maintaining its position with minimal distortion of the IVC wall's natural movement. This configuration can be achieved by appropriately selecting materials, surface features, and dimensions. For example, the length of the support segment of the frame must balance considerations of electrical performance and stability, where a shorter support segment length may tend to improve electrical performance, but a longer support segment length may increase stability.

[0067] To stimulate the RC-WVM implant 12 and receive signals back from the implant, the antenna module 16 will functionally include transmitting and receiving antennas (or multiple antennas). The antenna module 16 may therefore be provided with physically visible transmitting and receiving antennas, or, as in the exemplary system 10 described herein, by a single antenna that switches between transmitting and receiving modes. Figure 3 and Figure 3A The antenna stripe 16b shown in Figure -D illustrates an example of an antenna module 16 employing a single switched antenna. The single-loop antenna is formed from a single wire and is placed around the patient's abdomen. This wire antenna is directly connected to the control system 14.

[0068] In terms of mechanical construction, the antenna band 16b generally comprises stretchable mesh segments 72 and buckles 74 for connections to power and data links 24. In one embodiment, to accommodate patients with varying circumferences (e.g., circumferences ranging from approximately 700 to 1200 cm), a multi-layered construction made of a combination of high- and low-strength materials can be employed. In such embodiments, the base layer 76 is a combination of high-strength segments 76a and low-strength segments 76b, which are joined, for example, by stitching. The outer layer 78, having substantially the same profile as the base layer 76, can be entirely constructed of a high-strength material, which may be a 3D mesh fabric. Within each segment, antenna cores 82 are provided in a serpentine configuration, with an overall length sufficient to accommodate the total stretch of the segment. The cores 82 themselves should not be stretched. Thus, the stretchability of the fabric layers is matched to the total length of the cores to meet the desired circumference adaptation for a particular band design. The outer layer 78 is joined to the base layer 76 along its edges. Covering the stitches with an adhesive material 80 is a suitable method for joining the two layers. The layers can be further bonded together by a heat-fused bonding material placed between the layers. The end 81 of the mesh segment 72 is configured to be attached to the buckle 74.

[0069] The core wire 82 forming the antenna element is disposed between layers and provided in an extendable serpentine configuration, allowing it to expand and contract as the band is stretched. The middle section 84 of the core wire 82, corresponding to the low-stretch section 76b, has a larger width. This section provides maximum sensitivity for reading signals from the RC-WVM implant 12, and is designed to be placed in the middle of the patient's back when the antenna band 16b is worn approximately at chest level at the bottom of the chest cavity. As a possible example, the core wire 82 can be made of 300 strands of stranded 46AWG copper wire, with a total length in the range of approximately 0.5-3 m. For an antenna band configured to stretch to accommodate a patient circumference in the range of approximately 700 to 1200 mm, the total length of the core wire 82 can be approximately 2 m. In some embodiments, it is preferred that the antenna band be placed closer to the tail end, at a height approximately at the patient's elbow when standing.

[0070] Numerous ways to provide an operable buckle for such an antenna band can be derived by those skilled in the art based on the teachings contained herein. Factors to consider in designing such a buckle include physical security, ease of manipulation by a less dexterous person, and protection against electric shock caused by careless contact with the electrical connector. As an example, buckle 74 comprises two halves, an inner half 74a and an outer half 74b. Buckle 74 provides not only a physical connection for the ends of the band but also an electrical connection for the antenna circuitry formed by the core wire 82. Regarding the physical connection, buckle 74 is relatively large to facilitate manipulation by a less dexterous person. Magnetic latches can be employed to assist closure, for example, a magnetic pad 86a on the inner half 74a connecting to a corresponding magnetic pad 86b on the outer half 74b. When needed, the system can be configured to monitor the integrity of the band circuitry and thus detect band closure. After confirming band closure, the system can be configured to assess the signal strength received from the implant and determine whether the received signal is sufficient for complete reading. If the signal is insufficient, instructions can be given to reposition the band to a better location on the patient.

[0071] Electrical connection of core wire 82 can be provided by recessed connector pins located on opposite connector halves 88a and 88b. Connection of power and data link 24 can be provided, for example, via coaxial RF cable, with coaxial connectors (e.g., SMA plugs) at buckle 74 and control system 14. As just one possible example, a suitable length for the power and data link using conventional 50-ohm coaxial cable is approximately 3 meters.

[0072] As mentioned above, using a single-coil antenna, as in antenna band 16b, requires switching the antenna between transmit and receive modes. This switching is performed within control system 14, an example of which is schematically depicted as follows: Figure 4 The control system 14a is described above. In this embodiment, the control system 14a includes functional modules 20, namely a signal generator module 20a and a receiver-amplifier module 20b. These functional modules, together with the transmit / receive (T / R) switch 92, provide the necessary switching of the antenna band 16b between transmit and receive modes.

[0073] Figure 3E The magnetic field generated by antenna band 16b is schematically illustrated. Interaction with RC-WVM implant 12. Both the antenna strip 16b and the implant 12 are generally arranged around axis (A). For optimal results using a strip antenna, each will be oriented in a substantially parallel direction around its axis, and to a feasible extent, will be coincidentally positioned, such as... Figure 3E As shown. When properly oriented relative to each other, the current (I) in the core wire 82 of antenna strip 16b generates a magnetic field. The magnetic field The coil of implant 12 is excited so that it resonates at a resonant frequency corresponding to its size / geometry at the time of excitation. For example... Figure 3E The antenna strip 16b shown here is oriented to minimize the power required to excite the implant coil and generate a readable resonant frequency response signal between it and the implant 12.

[0074] As with any RF coil antenna system, the antenna and system must be matched and tuned for optimal performance. The values ​​of inductance, capacitance, and resistance, and their interrelationships, should be carefully considered. For example, the coil inductance determines the tuning capacitance, while the coil resistance (including the tuning capacitance) determines the matching capacitance and inductance. Given the relatively low power of the disclosed system, these aspects are given particular attention to ensure that the RC-WVM implant 12 generates a sufficiently readable signal when actuated by a driving magnetic field. The use of adjustable bands, such as antenna band 16b (or using antenna bands of different sizes), raises additional considerations due to the variable or different lengths of the antenna coil controlled by the control system. To address these considerations, as understood in the art, separate tuning-matching circuits 94, 96 are provided in the signal generator module 20a and the receiver-amplifier module 20b, respectively. Figure 4 ).

[0075] Using conventional coaxial cable for RF power transfer, as described above in one embodiment of power and data link 24, optimal RF power transfer between the antenna and control system is achieved when the system and antenna impedances are matched to a real resistance of 50 ohms. However, in the embodiment described above, the resistance of antenna band 16b is typically much lower than 50 ohms. A conversion circuit, as part of tuning-matching circuits 94, 96, can be used to convert the antenna resistance to 50 ohms. In the case of antenna band 16b, a parallel capacitor conversion circuit has been found to be effective for this purpose.

[0076] In one example of tuning using the aforementioned system components, a series capacitor was used, which, together with a matching capacitor, forms the overall resonance. Using the measurements described in Table II below, the target resonant frequency was calculated to be 2.6 MHz based on inductance and capacitance. Considering the change in inductance due to stretching of antenna strip 16b at 2.6 MHz, for a length variation of antenna strip 16b's perimeter between 1200 mm and 700 mm, the resonant frequency was measured to change only from approximately 2.5 MHz to approximately 2.6 MHz. Considering a resistance of 11.1 ohms, the Q factor of the cable / strip assembly was calculated to be 3. This low Q factor translates to a full width at half maximum (FWHM) of the pulse at 600 kHz. This is much smaller than the change in resonant frequency caused by stretching the strip's perimeter from 700 mm to 1200 mm. Therefore, the tuning value for antenna strip 16b was determined to be C at 2.6 MHz. 匹配 =2.2nF and C 调谐 =2.2nF.

[0077]

[0078] While it can be expected that variable-length antennas, such as those included in antenna strip 16b, may face difficulties in tuning and maintaining the antenna as the length changes, this has not been found when utilizing this configuration. As described above, by intentionally employing cables for the power and data links 24 with relatively large inductance compared to the antenna inductance, the proportional change in inductance caused by the change in strip diameter is too small to degrade performance.

[0079] Refer again Figure 4 In addition to the tuning-matching circuitry 94, the signal generator module 20a also includes components for generating the signal required to excite the RC-WVM implant 12. These components include a direct digital synthesizer (DDS) 98, an anti-aliasing filter 100, a preamplifier 102, and an output amplifier 104. In one embodiment, the signal generator module 20a is configured to generate an RF burst excitation signal having a single, invariant frequency tailored to a specific RC-WVM implant paired with the system (exemplary waveforms are shown in...). Figure 5A and Figure 5B (As shown in the diagram). An RF burst comprises a predetermined number of sinusoidal pulses at a selected frequency with a set interval between bursts. The selected RF burst frequency value corresponds to the intrinsic frequency of the paired RC-WVM implant 12 that will produce the lowest amplitude in the implant reader output. By doing so, optimal excitation is achieved under the worst-case scenario of the implant response signal.

[0080] In an alternative implementation, the control system 14 excites the antenna module 16 at a predetermined frequency within the expected bandwidth of the paired RC-WVM implant 12. The system then detects the response from the paired RC-WVM implant and determines the implant's intrinsic frequency. The control system 14 then adjusts the excitation frequency to match the intrinsic frequency of the paired implant and continues to excite at that frequency throughout the complete readout cycle. As those skilled in the art will understand, the frequency determination and adjustment described with respect to this embodiment can be implemented via software using digital signal processing and analysis.

[0081] In another alternative implementation, each individual RF burst comprises a continuous frequency sweep within a predetermined frequency range equal to the possible bandwidth of the implant. Figure 6A This generates broadband pulses that can excite the implant at all possible intrinsic frequencies. Figure 6B The excitation signal can continue in this "burst frequency scan mode", or the control system can determine the sensor's natural frequency and adjust it to emit only at the natural frequency.

[0082] In a further alternative implementation, excitation involves a brief sweep of frequencies covering a set of discrete frequency values ​​that encompass the possible bandwidth of the paired RC-WVM implant 12. The frequency is sequentially incremented for each RF burst, and the RMS value of the RC-WVM implant response is evaluated after each increment. The control system 14 then establishes the frequency at which the RC-WVM implant response produces the maximum amplitude and continues to excite the paired RC-WVM implant at that frequency until a predetermined amplitude drop is detected, and then restarts the frequency sweep.

[0083] In another implementation, the excitation signal comprises a predetermined set of frequencies, each of which remains constant. The control system 14 excites the antenna module 16 (and thus the paired implant) by applying equal amplitudes across all frequency components. The system detects the response from the paired implant and determines its intrinsic frequency. The control system 14 then adjusts the relative amplitudes of the excitation frequency set to maximize the amplitude of the excitation frequency closest to the intrinsic frequency of the paired implant. The amplitudes of other frequencies are optimized to maximize the response of the paired implant while meeting electromagnetic radiation and transmission bandwidth limitations.

[0084] In another implementation, the direct digital synthesizer (DDS) 98 can be provided as a multi-channel DDS system to generate a predetermined number of simultaneous discrete frequencies, which belong to, as in Figure 7A and Figure 7BThe estimated operating bandwidth of the paired RC-WVM implant 12 is shown. Therefore, the amplitude of each frequency component can be independently controlled to provide optimal excitation to that particular RC-WVM implant 12 based on the individual coil characteristics of that particular RC-WVM implant 12. Additionally, the relative amplitude of each frequency component can be independently controlled to provide optimal excitation to the implant, i.e., the amplitude of the frequency components is selected in a way that maximizes the excitation signal in the worst-case scenario (i.e., maximum compression) that causes the paired implant to emit a response signal. In this arrangement, a summing amplifier 120 based on a high-speed operational amplifier is used to sum all the outputs from the multi-channel DDS system 98.

[0085] In another implementation, the signal generator module 20a can be configured to provide, for example... Figure 8 The pulse shaping is illustrated. Arbitrary waveform generation based on a direct digital synthesizer 98 is used to generate a pulse with a predetermined shape, and the spectrum of this pulse with the predetermined shape is optimized to maximize the response of the paired RC-WVM implant 12. The amplitude of the frequency components that cause a decrease in the loopback signal amplitude is maximized, while the amplitude of the frequency components that cause an increase in the loopback signal amplitude is reduced, so as to obtain a substantially constant output signal amplitude and thus an improved response from the RC-WVM implant 12.

[0086] Refer again Figure 4In addition to the tuning-matching circuit 96, the receiver module 20b also includes components for implant response detection, data conversion and acquisition for signal analysis, such as a single-ended input to differential output circuit (SE to DIFF) 106, a variable gain amplifier (VGA) 108, a filter amplifier 110, and an output filter 112. During the reception period, the T / R switch 92 connects the antenna band 16b to the receiver-amplifier 20b via the tuning and matching network 96. The response signal sensed by the implant 12 in the antenna band 16b is applied to the unity-gain single-ended to differential amplifier 106. The conversion from single-ended to differential mode helps to eliminate common-mode noise from the implant response signal. Since the amplitude of the implant response signal is in the microvolt range, the signal is fed into the variable gain differential amplifier 108 after the single-ended to differential conversion, which is capable of providing a voltage gain of up to 80 dB (10,000 times). The amplified signal is then applied to an active bandpass filter-amplifier 110 to eliminate out-of-band frequency components and provide additional amplification. The resulting signal is applied to a passive high-order low-pass filter 112 for further elimination of out-of-band high-frequency components. The output of the filter is fed into a data conversion and communication module 22. The data conversion and communication module 22 includes components for providing data acquisition and transmission from the electronic system to an external processing unit. A high-speed analog-to-digital converter (ADC) 114 converts the output signal of the receiver module 20b into a digital signal with a predetermined number of bits (e.g., 12 bits). This digital signal is transmitted to the microcontroller 116 in parallel mode. In one implementation, a level offset circuit is used to match the logic level of the ADC with that of the microcontroller. The data output by the ADC is stored sequentially in the microcontroller's internal flash memory. Direct memory access (DMA) is used in this process to maximize data throughput. The microcontroller 116 is synchronized with a direct digital synthesizer 98, so data acquisition begins when an RF burst is emitted to excite the implant 12. Once triggered, the microcontroller captures a predetermined number of samples (e.g., 1024). The number of samples multiplied by the sampling period defines an observation window within which the response signal from implant 12 is evaluated. This observation window is matched with the length of the response signal from implant 12, the length of which depends on the time constant of signal attenuation.

[0087] As a means of reducing noise, the response signal of implant 12 is observed a predetermined number of times (e.g., 256 times), and then the average response is calculated. This method greatly helps to increase the signal-to-noise ratio of the detected signal.

[0088] Next, the average response is transmitted to the external interface device 18 (e.g., a laptop computer) via communication module 118. This can be done in different ways. In one embodiment, communication is performed using a UART interface from the microcontroller, and external hardware is used to convert the UART to USB. In a second embodiment, a microcontroller with USB drive capability is used, and in this case, the connection to the external interface device is achieved using only a USB cable. In yet another implementation, communication between the microcontroller and the external interface device is wireless (e.g., via Bluetooth).

[0089] The system is powered by a low-voltage power supply unit (PSU) consisting of an AC-DC converter, conforming to Clause 8 of IEC 60601-1:2005+AMD 1:2012. This AC-DC converter has insulation between the mains input and output, providing at least two means of patient protection (MOPP). In this way, the power supply provides protection against electric shock to the user. The PSU is adaptable to a wide range of mains voltages (e.g., from 90 to 264 VAC) and mains frequencies (e.g., 47 to 63 Hz) to allow operation in different countries with different mains specifications.

[0090] As described above, the control system 14a utilizes software-based frequency detection. Therefore, in terms of signal transmission, once the excitation frequency is optimized, the system 10 employing the control system 14a with the signal generator module 20a operates in open-loop mode; that is, one or more frequencies and amplitudes of the transmitted signal are unaffected by the response of the RC-WVM implant 12. On the receiving side, using the amplifier-receiver module 20b, the control system 14a detects the response signal from the RC-WVM implant 12 and digitizes the signal using a high-speed data converter. The raw digitized data is then transmitted to a processing unit (e.g., a laptop computer or other device microcontroller) and digital signal analysis techniques (e.g., Fast Fourier Transform) are applied to establish the frequency content of the signal. Therefore, one advantage of using these software-based techniques is that phase-locked loop (PLL) circuitry or similar circuitry is not used or required in the control system 14a.

[0091] Another component of the overall RC-WVM system described in this article is the RC-WVM implant delivery system. Figure 9 and Figure 9AAspects of an endovascular delivery system for placing an RC-WVM implant 12 at a desired monitoring location within an IVC are schematically illustrated. The delivery system generally includes a delivery catheter 122 comprising an outer sheath 124 and a pusher 126 configured to be received within the lumen of the outer sheath 124. Insertion of devices into the circulatory system of humans or other animals is generally well known in the art and therefore not described in detail herein. Those skilled in the art will understand upon reading this disclosure in its entirety that the RC-WVM implant 12 can be delivered to a desired location in the circulatory system using, for example, a loading tool for loading a sterile RC-WVM implant into a sterile delivery system, which can be used to deliver the RC-WVM implant to the IVC via a femoral vein or other peripheral vascular access point, but other methods may also be used. Typically, the RC-WVM implant 12 will be implanted using a delivery catheter, of which delivery catheter 122 is an illustrative example, and the RC-WVM implant 12 will be optimized for delivery via the smallest possible catheter. To facilitate this operation, the bend in the implant crown segment 40 (or the ear portion as described later, collectively referred to as the "sensor construction end") can be a bend with a smaller radius to facilitate a low profile when inserted into the delivery catheter, as shown. In an alternative, the pusher 126 may be provided with a stepped distal end 128 having a reduced-diameter end portion 130 configured to engage the inner periphery of the RC-WVM implant 12 when it is compressed for delivery. For the use of anchors (e.g., Figure 2 Anchoring component 48 or Figure 11A In an implant embodiment (such as the anchor 48s), the end portion 130 can be configured to engage the inner periphery defined by the anchor in a compression configuration, such as... Figure 9 As shown. Alternatively, the distal end 128 of the actuator may be provided with a straight, flat end or other end shape configured to cooperate with a particular RC-WVM implant and anchor design. For example, as Figure 9A As shown, it has an anchoring frame 150 (see example). Figure 17 and Figure 18 The RC-WVM implant 12t can be deployed with a flat distal pusher 128 abutting against the coronal segment 40 of the implant 12t, and an anchoring frame 150 disposed opposite to the pusher 128.

[0092] In one deployment option, the RC-WVM implant can be inserted into the IVC from a peripheral vein (such as the femoral or iliac vein) to be positioned at a monitoring location between the hepatic and renal veins. It should be understood that the implant can also be introduced from other venous locations. Depending on the implant configuration, when placed in the IVC for fluid state monitoring, a specific orientation of the RC-WVM implant 12 may be required to optimize communication with the reader antenna coil. To facilitate the desired placement or positioning, the length and diameter of the RC-WVM implant 12 can be designed such that it gradually expands (“blooms”) as it is held in proper position using the pusher 126 and the sheath 124 is withdrawn. This gradual partial deployment helps ensure that the RC-WVM implant 12 is properly positioned in the IVC. The ratio of sensor length to vessel diameter (where the length is always greater than the vessel diameter) is also an important design factor to ensure that the sensor is deployed in the correct orientation within the IVC. In another alternative, the distal end 128 of the pusher 126 can be configured to releasably retain the anchor or proximal portion of the implant before it is fully deployed from the outer sheath 124, allowing the implant to retract for repositioning if needed. For example, small radially extending studs can be positioned near the end of the end portion 130, which engages behind the proximal coronal portion of the implant 12 once the implant 12 is compressed within the outer sheath 124, thereby allowing the implant to be pulled back from the partially deployed position but self-released from the studs upon full deployment after confirmed positioning. Conventional radiographic markings can be provided at or near the distal end of the outer sheath 124 and / or the pusher 126, and on the RC-WVM implant 12, to aid visualization during implant positioning and deployment. Typically, when using anchoring features, the implant is positioned using anchoring features with proximal orientation; therefore, the anchor is the last part to be deployed to facilitate proper orientation within the IVC and may allow for pull-back and repositioning if necessary. Once the implant is fully deployed, the delivery catheter 122 can be withdrawn from the patient, leaving the implant 12 as a discrete, self-contained unit in the vessel without any attached lines, leads, or other structures extending away from the monitoring location.

[0093] Example 1

[0094] RC-WVM implant 12a is already in use (e.g.) Figure 2 (in the middle), similar to antenna band 16b (such as...) Figure 3 Antenna stripes and control systems 14a (e.g.) Figure 4 The system described herein was evaluated in pre-clinical testing (in China). Delivery system 122 (e.g., Figure 9(Intravascular ultrasound and antenna band were used to deploy the implant into the sheep's IVC.)

[0095] Figure 10A , Figure 10B and Figure 10C The original ring down signal, the detection of the maximum frequency, and the conversion from the maximum frequency to the IVC area using the reference characteristic curve are shown respectively. Figure 10A The original loop-drop signal in the time domain is shown, where the resonant response of the RC-WVM implant decays over time. Modulation of the implant geometry causes a change in the resonant frequency, which can be viewed as a difference between two distinct plotted traces. Figure 10B The RC-WVM implant signal, transformed to the frequency domain and plotted over time, is shown. (E.g., using Fast Fourier Transform) Determined and plotted over time. Figure 10A The maximum frequency in the signal. Larger, slower modulations of the signal (i.e., three broad spikes) indicate respiratory-induced motion of the IVC wall, while faster, smaller modulations superimposed on the signal indicate motion of the IVC wall in response to the cardiac cycle. Figure 10C It shows in Figure 10A The frequency modulation is converted into an IVC area versus time plot. (In this case, the conversion is based on characteristic curves determined by bench testing on a range of sample diameter lumens following standard laboratory / testing procedures.) Figure 10C Therefore, the IVC area at the monitoring location is shown to respond to changes in the respiratory and cardiac cycles.

[0096] Figure 10D and Figure 10E The paper demonstrates the ability of the RC-WVM implant 12 (in this case, implant 12a) to detect changes in IVC area due to fluid loading. In one example, Figure 10D The results are shown in the paper, which describes how, after placing the RC-WVM implant 12 in the IVC of sheep and confirming that the implant signal was received, a 100 ml fluid dose was added to the animal at a rate of 10 ml / s. Figure 10D The gray band in the figure indicates the application of fluid dosage. As reflected by the reduced-frequency ring-back signal from the RC-WVM implant 12, the added flow capacity causes the IVC and the implant to expand, which in turn causes a change in the inductance of the implant, thus altering the frequency of its ring-back response to excitation. In another example, the result is... Figure 10E The diagram shows a tilted operating table used to transfer fluids within the animal's body. From Figure 10EStarting from the left, the first gray band indicates the time when the stage was initially tilted. The tilting of the stage causes fluid to shift away from the IVC, resulting in a smaller IVC diameter and thus increasing the frequency of the loopback signal of the RC-WVM implant 12 as it moves into the smaller diameter IVC. The second gray band indicates the time when the stage returns from tilt to a flat position. At this point, fluid shifts back into the IVC, causing the IVC to increase in size due to the increased fluid volume and thus decreasing the frequency of the loopback signal as explained above.

[0097] Therefore, these output signals demonstrate the detection of IVC modulation with respiration. Specifically, it should be understood that embodiments of the present invention can thus provide a surprisingly powerful diagnostic tool that can not only identify the general trend of IVC geometry changes, but also distinguish in real time changes in IVC geometry caused by respiration and cardiac function.

[0098] RC-WVM Implant Design Considerations and Alternative Implant Examples

[0099] It should be understood that measuring the dimensional changes of an IVC presents unique considerations and requirements due to the IVC's unique anatomy. For example, an IVC is a relatively low-pressure, thin-walled vessel that not only changes in diameter but also in its overall shape (cross-sectional profile) corresponding to changes in blood volume and pressure. An IVC does not dilate and constrict symmetrically around its circumference, but rather expands and collapses primarily in an anterior-posterior direction from a relatively circular cross-section at higher volume to a flattened elliptical cross-section at lower volume. Therefore, embodiments of the RC-WVM implant 12 must monitor this asymmetric low-pressure collapse and dilation in the AP direction without excessive radial restraint, and must also use sufficient force to engage the vessel wall to firmly anchor the implant and prevent migration. Thus, the RC-WVM implant 12 must be able to collapse in the AP direction along with the vessel from a generally circular cross-section to an elliptical or flattened cross-section without excessive distortion of the vessel's natural shape. These requirements are achieved through appropriate selection of material compliance and configuration according to several embodiments described herein, such that the coil measurement section of the RC-WVM implant 12 remains in contact with the IVC wall without inappropriate radial pressure that could cause it to twist. For example, the RC-WVM implant 12 according to embodiments described herein can apply a radial force in the range of about 0.05N-0.3N under 50% compression. Alternatively, increased positioning safety can be achieved without compromising measurement response by physically separating the anchoring section and the measurement section to move any potential twisting of the vessel wall caused by anchoring to a sufficient distance from the measurement section without affecting the measurement.

[0100] The RC-WVM implant 12 described herein can be configured in various structures, such as collapsible loops or tubes formed of wire with elastic sinusoidal or "Z-shaped" bends, or in more complex collapsible shapes, where more elastic regions (such as "ridges") are connected by relatively less elastic regions (such as "ears"). Each structure is configured based on size, shape, and material to maintain its positioning and orientation via bias between the elastic elements of the implant to ensure contact with the vessel wall. Additionally or alternatively, anchors, surface textures, barbs, scales, pins, or other fastening elements may be placed on the structure for more secure engagement with the vessel wall. Coatings or coverings may also be used to promote inward tissue growth. In some embodiments, it may be preferred to configure specific portions of the structure (e.g., coil ridges) to position and maintain the engagement portion to reduce any effect of biasing forces on movement of the vessel wall, such as that sensed at the coil ear, or vice versa. In other embodiments, separate anchoring structures may be coupled to the coil measurement portion of the implant. These anchoring structures may include hooks, expandable tubular elements, or other tissue-attaching elements that engage blood vessels upstream or downstream of the coil portion to minimize any interference with the natural expansion or contraction of blood vessels in the region of the coil itself. Sensing modes and positioning are described in more detail below.

[0101] When the RC-WVM implant 12 is energized, it must generate a signal of sufficient strength to be wirelessly received by an external system. In the case of a variable inductor circuit, the coil transmitting the signal to the external receiver must maintain a tubular shape or have a central antenna aperture of sufficient size, even when the blood vessel collapses, so that its inductance is sufficient to generate a field strong enough to be detected by the external antenna. Therefore, in some embodiments, it may be desirable for the variable inductor to have a collapsed portion that deforms with the expansion and collapse of the blood vessel and a non-collapsed portion that deforms relatively little when the blood vessel collapses and expands. In this way, a considerable portion of the coil remains open, even when the blood vessel collapses. In other embodiments, the coil may be configured to deform in a first plane containing the anterior-posterior axis and deflect relatively less in a second orthogonal plane containing the lateral-inner axis. In other embodiments, a first inductive coil that expands and collapses with the blood vessel may be provided, and a separate transmitting coil that deforms substantially little may be provided to transmit the signal to the external receiver. In some cases, the transmitting coil may also serve as an anchoring portion of the implant.

[0102] Turning to the specific alternative RC-WVM implant embodiments disclosed herein, the first exemplary alternative embodiment is... Figure 11A , Figure 11B , Figure 11C The RC-WVM implant 12s shown and Figure 14A , Figure 14B and Figure 14CThe alternative anchor 48s is shown in the figure.

[0103] The RC-WVM implant 12s utilizes PTFE-coated Kinlitz wires 42s wound around a nickel-titanium alloy wire frame 44s. PTFE has good heat resistance to withstand the manufacturing process while also being biocompatible. The overall configuration of the implant 12s includes a support segment 38 and a crown segment 40, substantially as described above. Alternatively, as described below, anchors 48s are secured near the crown segment 40. A section of heat-shrink tubing 61s is used to help ensure the compression of the return material and can be removed in a later assembly step. A section of heat-shrink tubing 60s can be used to cover and insulate the capacitor 46s, which in one embodiment may be a 47nF capacitor, or the heat-shrink tubing may also be removed as described above.

[0104] The capacitor 46s can include any suitable structure to provide the desired capacitance, such as the 47nF capacitor mentioned in one embodiment. For example, the desired capacitance can be achieved by gaps of a specific size, different terminal materials (e.g., leads, etc.), overlapping wires, or it can be a gap with a specific dielectric value in a tube. In the illustrated exemplary embodiment, the surface mount capacitor 46s is soldered between two terminals 56s formed by the connection of 300 strands of Litz wire 42s. Other electrical attachments can also be used, such as crimping or direct attachment to terminals with brazing caps without soldering. The capacitor segment is then encapsulated using a reflow process, which includes positioning a polymer reflow tube 59s on the capacitor, connectors, and terminals, followed by positioning a heat shrink tube 60s over the reflow tube. Before the capacitor is soldered in place, the reflow tube 59s and the heat shrink tube 60s are placed on the Litz wire / NiTi alloy frame assembly ( Figure 12 The illustration shows the return tube and heat-shrink tube used for the anchor (they are similarly positioned). The outer diameter of these tubes and their fitting tolerances are selected to facilitate assembly, minimize the overall profile of the final implant configuration, and optimize material flowability to increase bond strength. Heat is then applied to melt the polymer tube and shrink it using heat shrink technology, thereby compressing the molten polymer onto the capacitor to form a seal. The heat-shrink tube is then removed. Alternative designs may employ overmolding processes, impregnation processes, epoxy potting, or similar processes using appropriate biocompatible materials.

[0105] Details of the alternative anchor 48s are in Figure 14A -C is shown. The anchor 48s typically has at least two segments: an attachment segment 49s to the implant and an anchoring segment 51s providing fixation to the vessel wall. In some embodiments, such as Figure 14AAs shown in -C, the additional isolation segment 53s is located between the anchoring segment and the attachment segment to allow independent mechanical movement between the anchoring segment and the attachment segment, thereby helping to isolate the function of the anchor acting on the vessel wall from the sensing function of the implant. Multiple anchors 48s can be used in the anchoring system, wherein multiple attachment segments 49s form the attachment segment of the anchoring system, and multiple anchors or anchor segments 48s form the anchoring segment of the anchoring system.

[0106] The anchor 48s can be formed by laser-cutting a pattern from a nickel-titanium alloy tube and shaping the anchor barbs via a heat treatment process. Other embodiments can be formed using various material wires, shaped or bent using standard processes, or laser-cut from other metals or bioabsorbable polymers. The outer surface of the anchor can utilize different shapes or surface finishes to engage the vessel wall and prevent implant migration. The overall length of the anchor 48s, extending beyond the coronary segment 40 of the implant 12s, is selected to facilitate deployment from the delivery system 122. Figure 9 The expansion of the implant, while minimizing its impact on the movement of the implant with the blood vessel. This occurs, as described above, when the distal end of the implant ejects from the outer sheath 124 and engages with the vessel wall. The length of the anchor protrusion is selected to allow expansion to occur effectively. If the protrusion is too long, the implant may not be able to be deployed in the desired expanding, blooming manner. In one embodiment, the protrusion of the anchor extending beyond the coronal segment 40 ( Figure 11B The dimension D) is smaller than the inner diameter of the outer sheath 124 of the delivery catheter.

[0107] The attachment section 49s can be formed using a tube laser cutting process to create a helical section of the tube. For example... Figure 12 As indicated, each anchor 48s is positioned by winding the helical portion of the attachment segment around the sensor post. In one embodiment, the internal dimension of the helical portion of the attachment segment is smaller than the external dimension of the implant post 38, creating an interference fit to secure the anchor in place. In another embodiment, the internal dimension of the helical portion is smaller than the external dimension of the terminal 56s, but larger than the external dimension of the implant post 38, and therefore can be moved once properly wound onto the post. In an illustrative example, for an implant coil post with a nominal diameter of approximately 1.143 mm, the inner diameter of the helical portion of the attachment segment can be approximately 1.156 ± 0.05 mm (outer diameter approximately 1.556 ± 0.05 mm). Typically, the relative dimensions of the implant coil outer diameter and the inner diameter of the anchor helical portion can be selected to provide a positional interference fit.

[0108] After the anchor is placed on the implant support, a polymer return tube 59s is positioned above the assembly, and an additional heat-shrink tube 61s is placed above the assembly. Heat is then applied to melt the polymer tube and cause it to shrink, thereby forcing the polymer between the spaces in the helix of the anchoring section, thus strengthening the anchor's fixation to the implant assembly. The dimensions of the return tube 59s can also be designed to have a slight interference fit between the outer surface of the implant assembly and the inner surface of the anchor attachment section to provide some longitudinal and rotational fixation during assembly. The spacing between the helices is designed to allow return material to flow into the space and form an adhesive. The width of the helix is ​​designed to allow the helical section to be manipulated into place during assembly while still providing sufficient rigidity when fully assembled. The thickness of the section is minimized to reduce the overall profile of the implant. One advantage of using the helical portion as the attachment means for the attachment section 49s is that it allows the anchor to be attached to any wire-based implant, including insulated wire implants, without interfering with or penetrating the insulation layer. As described, the spiral portion distributes the adhesion force throughout the entire space of the insulating layer to avoid damage to the layer, and the space between the spirals facilitates adhesive attachment. Another advantage of using the spiral portion for attachment as described above is that the aspect ratio of the spiral segment can be selected to allow the spiral to loosen slightly, thereby allowing the anchor to be placed in the middle of the implant support segment without having to pass through the end of the capacitor terminal. Alternative embodiments of the attachment segment 49s can employ other shapes, such as a T-shape instead of a spiral segment, to prevent rotation and detachment from the sensor. Further alternatives may include replacing the polymer return tube 59s with a heat-shrinkable part that can only remain in place, or using adhesives or other bonding techniques.

[0109] like Figure 14A As shown in -C, the anchoring segment 51s includes two laser-cut and shaped anchoring barbs 50s. The barbs 50s are positioned on the vessel-facing surface of the anchor and, in some embodiments, are tilted at an angle between approximately 10 and 80 degrees to provide fixation to the vessel wall, resistance to anterior and posterior implant migration, and also facilitate collapse for loading and deployment of the implant via its delivery system. The barbs 50s are shaped to engage the vessel wall and have a length sufficient to pierce the vessel without penetrating it, typically between approximately 0.5 and 2.0 mm. The distal end of the anchoring segment 51s may have a flat end face 47s to engage with the pusher of the deployment system and may be chamfered to avoid any sharp edges that could cause unwanted vascular reaction or jamming on the delivery system. Other alternative embodiments may include multiple barbs or different surface treatments or barb shapes to optimize vascular fixation.

[0110] The isolation segment 53s is designed to isolate or reduce the transmission of mechanical movement from the anchoring segment 51s to the attachment segment 49s or from the attachment segment 49s to the anchoring segment 51s, allowing the implant to move freely and at least substantially free from torsion caused by contact between the anchoring segment and the vessel wall. The isolation segment 53s can therefore include a narrow cross-sectional area to provide flexibility while maintaining a constant thickness to provide adequate support. Rounded / curved surfaces, as shown, are maintained to avoid stress concentration, which can lead to fatigue or undesirable tissue damage. Alternative embodiments of the isolation segment 53s may include varying the tube thickness to provide greater flexibility, or varying the cross-section in a non-mirror manner to provide preferred flexibility in one direction.

[0111] Figure 15A and Figure 15B An alternative embodiment of the antenna band module 16s is shown. To accommodate patients of different circumferences, the band antenna 16s employs a loop antenna wire 82s mounted on or within the base layer 76s, which wraps around the patient to form a discontinuous circumferential loop. A communication link 24s is provided essentially as described above. By using a loop core wire, the core wire forms a loop antenna without necessarily extending all the way around the patient. In this way, a buckle or clasp (not shown) for band closure also does not need to provide an electrical connection to complete the antenna loop. Therefore, the simplified clasp can use variable connection methods, such as Velcro or other connection means, thereby eliminating the need for bands of various sizes. Figure 15A and Figure 15B As shown, the antenna strip 16s utilizes a single (or multiple) looped core wires 82s wound around the patient. When the base layer is wound around the patient, the loop ends 83s of the core wires 82s should be substantially adjacent, typically spaced approximately 2 cm to approximately 10 cm apart. Depending on specific design parameters, the signal strength provided by discontinuous looped core wires 82s may be less than that provided by continuous circumferential core wires 82s as described above. However, depending on the application and specific clinical requirements, the simplified looping and ease of use offered by the antenna strip module 16s can provide usability advantages exceeding signal requirements.

[0112] By adding recapture features at the distal end of the anchor and the tip of the actuator, the repositionability of the implant or even recapture with the deployment system can be improved, as illustrated in exemplary embodiments. Figure 16A and Figure 16B The image is shown in the diagram. This type of recapture feature allows the sensor to remain attached to the actuator even when partially deployed. From this point, the mechanical device can be used to fully deploy the sensor, reposition the device while the sensor is still attached to the actuator, or recapture the device by pushing the sheath over the sensor and removing the sensor. These features can take various forms, including interlocking elements, screws, or release lugs. In one embodiment, such as... Figure 16AAs illustrated, the recapture features 127, 129 may include a “T-shaped” extension 127 of the anchor that engages with a suitably shaped recess 129 in the distal end of the pusher 126. In another alternative, such as Figure 16B As shown, recapture features 127', 129' include a through-hole 127' in the distal end of the anchor, through which a pin-shaped extension 129' from the pusher 126 engages to provide engagement while remaining within the outer sheath 124. This type of recapture feature can be used for partial sensor deployment while retaining the ability to reposition or recapture the sensor. The recapture feature remains engaged while the distal end of the anchor remains within the sheath. When the operator is satisfied with the final position, the sheath is fully retracted, releasing the interlocking features and deploying the sensor.

[0113] Although the anchor 48s is in Figure 11A -C is shown as being attached only to one end of the implant (to facilitate the flowering deployment as described above), but it is conceivable that anchors can be placed at both ends of the implant, with fewer or more anchors provided compared to the four shown in the figure.

[0114] In other alternative embodiments, such as Figure 17-29D As shown, in contrast to the individual anchoring elements described above, one or more anchoring elements that help prevent migration can be provided as an integrated anchoring frame. In one example, such as Figure 17 As shown, the RC-WVM implant, including the anchoring frame 150, is attached to the RC-WVM sensor segment 12t. The RC-WVM sensor segment (or simply "sensor segment") 12t may include any previously described "Z-shaped" coil or a similar RC-WVM implant 12 as described above, which typically includes a support segment 38 joined by the crown segment 40. For clarity, reference is made to the following. Figure 17-29D In the described embodiments, the RC-WVM implant (or simply referred to as the "implant") refers to the combined RC-WVM sensor segment and anchor frame 150. The anchor frame 150 can be formed from a nickel-titanium alloy wire or a laser-cut tube, thereby expanding the tube to the equivalent diameter of the sensor segment. Nickel-titanium alloy or other materials with similar properties are well-suited for use as the material for the anchor frame 150 because it allows the anchor frame to collapse in the loader into the same loading configuration as the RC-WVM sensor segment (see [link to documentation]). Figure 9A ).

[0115] Figure 18An example of the anchoring frame 150 before attachment to a sensor segment (such as the RC-WVM sensor segment 12t) is shown. Similar to the RC-WVM sensor segment 12t, the anchoring frame 150 includes a series of straight support segments 152 (also referred to as anchoring segments) connected by curved crown segments 154 to form a flexible concentric zigzag or linked “Z-shaped” structure, which can also be visually considered sinusoidal. One or more anchoring barbs 156 are provided within the support segments or anchoring segments, as described in more detail below. Figure 17 and Figure 18 The anchoring frame 150 shown includes only a single anchoring barb 156 on each support section 152. The anchoring frame 150 is attached to the sensor section via an attachment arm 158 that overlaps with the support section 152 of the sensor section. It should also be noted that the crown section 154 at the end opposite the attachment section may be provided with recapture features, such as recapture features 127, 127', etc. Figure 16A and Figure 16B As shown, they cooperate with corresponding recapture features 129, 129′ formed on the distal end of the deployment actuator 126.

[0116] As in Figure 19 As shown, the polymerization return tube 160 is positioned above the attachment arm 158, and a further heat-shrinkable tube 162 is placed above the return tube. Figure 19 As illustrated, the attachment arm 158 is visible through the transparent return tube 160 and heat-shrink tube 162. Heat is then applied to melt the polymer in the return tube 160 and shrink the heat-shrink tube 162, thereby forcing the polymer between and around the attachment arms 158, thus securing the anchoring frame 150 to the RC-WMV sensor segment. The return tube 160 may be dimensionally designed to have a slight interference fit between the outer surface of the support segment 38 and the inner surface of the return tube to provide some longitudinal and rotational stability during assembly. The attachment arm 158 may be configured to include an anchoring isolation segment 159. The isolation segment 159 is an isolation device of one form as described above. The radial force requirements of the anchoring frame 150 and the function of the isolation segment 159 are also discussed in more detail below.

[0117] Attachment arm 158 may contain, for example Figure 19 The serrated configuration shown, where the space between the teeth 164 allows reflow material to flow between the teeth and form a stronger bond, is intended to increase bond strength. Other alternative configurations of the attachment arm 158 (which provide this increased surface area) are considered to increase bond strength, such as zigzag, T-shaped, S-shaped connectors, and the gap at the center of the support post. Figure 29A-D is shown. Other alternatives include surface finish or texturing on the attachment arm 158. In certain designs, such alternative configurations may allow for minimization of the attachment arm thickness to reduce the overall profile of the implant.

[0118] In some embodiments, such as Figure 18 and Figure 20 As shown, it may be desirable to provide a slit 166 in the anchor frame 150 to prevent the formation of a continuous loop of conductive material that could interfere with sensor readings. The slit 166 provides a discontinuity in the anchor frame to prevent magnetic fields from an external reader from coupling into the anchor frame and potentially providing interference from the RC-WVM implanted signal generated by the sensor segment. The slit 166 in the anchor frame 150 is advantageously located near the sensor segment, for example, approximately at the center of the anchor frame crown 154, such that the slit in the frame does not significantly compromise the structural integrity of the anchor frame 150. In one such example, as... Figure 18 and Figure 20 As shown, the slit crown 154S is provided with dual attachment arms 158, each attachment arm being secure to each support segment 38 on the opposite side of the corresponding implant crown segment 154. In other embodiments, the slit may be located at other locations on the anchoring frame, as described below. If desired, dual attachment arms 158 may also be provided for a seamless anchor crown 154.

[0119] In other embodiments, the decoupling slot 166 of the anchoring frame may be located at other locations on the frame, and in such cases, it is preferably structurally reinforced by bridging with an additional metal or polymer component that provides sufficient structural integrity to the anchoring frame while maintaining a discontinuous configuration. Alternatively, a continuous anchoring frame structure can be designed by carefully selecting the amount of metal material in the frame and the shape of the frame to minimize or control interference with the RC-WVM implant signal, allowing it to be otherwise compensated for in signal processing.

[0120] In some embodiments, the anchoring frame 150 may be attached to the RC-WVM sensor segment and loaded into the deployment system, wherein the orientation of the anchoring frame is first exposed during deployment. In this case, the pusher 126 of the delivery system 122 is carried on the crown segment 40 of the sensor segment (see, for example...). Figure 9A In other embodiments, this configuration can be reversed, with the sensor segment deployed first and the actuator of the deployment system carried on the coronal 154 of the anchoring frame 150. Orientation can vary depending on factors such as the implantation site (e.g., femoral vein versus jugular vein). In another alternative, such as... Figure 21As shown, to improve anchoring, the anchoring frame 150 can be positioned at each end of the RC-WVM implant (e.g., sensor segment 12t), in which case the anchoring frame will be deployed first regardless of the orientation of the RC-WVM implant in the delivery system.

[0121] Once the RC-WVM implant with anchoring frame 150 is deployed in the blood vessel, barbs 156 engage with the vessel wall in various orientations to prevent movement of the device. Figure 22A , Figure 22B and Figure 22C An embodiment of the anchoring frame 150a is shown, wherein the anchoring barbs 156a are configured parallel to the anchoring frame struts 152. It should also be noted that the anchoring frame 150 may employ two attachment arms 158 at each coronal portion facing the implant, some arms having serrations 164 while others do not. In another embodiment, the planar orientation of the anchoring barbs may be offset such that any increment between the axial direction of blood flow within the IVC or the indicated size range for the RC-WVM implant corresponds to the axial direction. Figure 22C Anchor barb 156a is depicted, which in its final shape is parallel to the post 150a to which it is attached, but its shape is such that its tip is not in the plane defined by the post and the parallel barb, i.e., in the case of... Figure 22C The protrusion is outside the plane of the page shown. This out-of-plane protrusion facilitates the anchor's engagement with the vessel wall, thereby preventing migration. The anchor is deployed in... Figure 22A As shown in the figure, the anchor is parallel to the strut 150a and therefore at an angle to the direction of blood flow in the blood vessel.

[0122] In another example, such as Figure 23A , Figure 23B and Figure 23C As shown, the axially facing anchoring barb 156b is positioned such that when the anchoring frame 150b is deployed within the blood vessel, the anchoring barb 156b is parallel (or nearly parallel) to the blood vessel direction and parallel to the flow within the blood vessel. In another embodiment, as... Figure 24A and Figure 24B As shown, the anchoring barb 156c of the anchoring frame 150c is located at the coronal portion 154 of the anchoring frame and extends outward to form an engagement vessel wall. Figure 24A and Figure 24B Examples of possible approximate dimensions for embodiments of the anchoring frame are also provided. Figure 23CAn anchoring barb 156b is depicted, which, in its final shape, is angled to the attached post 150b, and is positioned such that its tip is also outside the plane defined by the anchoring barb and the attached post. This out-of-plane protrusion on both axes facilitates better, more axial orientation of the anchoring member to engage with the vessel wall, thereby potentially providing increased resistance to migration. The deployment configuration of this anchoring member is... Figure 23A As shown, the anchor is angled to the support 150b and therefore generally parallel to the direction of blood flow in the vessel. This final positioning of the anchor tip (offset from the plane of the support on both axes) is also possible in... Figure 25A I saw it in the middle.

[0123] Figure 25A An anchoring frame embodiment 150a is depicted, which has straight support segments 152s formed between coronary segments 154. The straight support segments 152s offer the advantage that the support segments remain in contact with the vessel wall throughout their entire length, regardless of the size of the vessel in which they are deployed. When the frame is formed, for example, by laser cutting the structure from a nickel-titanium alloy tube, the straight configuration of the straight support segments 152s can be achieved by shaping the support segments to maintain the desired straight configuration. Figure 25B An alternative anchoring frame embodiment 150b is shown, which is formed around the surface of a cylindrical mandrel, resulting in a curved support section 152c. The curved support section 152c has the advantage of increasing the local force for pushing the anchoring barbs 156 (shown as double barbs) into the vessel wall for fixation, but may have the disadvantage of the coronary not contacting the vessel wall, especially when the device is implanted in a small vessel.

[0124] Various orientations and configurations of the anchor barb 156 can be achieved in, for example Figure 26A-26G The different embodiments illustrated herein are provided. For example, such as... Figure 26A As shown, the anchoring barbs 156 may extend outward at an angle (A) between approximately 10° and 90° at the center of each post 152 of the anchoring frame 150. The anchoring barbs 156 may alternately face one or both of the rearward or forward directions within the plane of the shaped post 152, or extend beyond that plane. In another embodiment, as... Figure 26B As shown, each support 152 can have multiple anchoring barbs 156a facing each direction. For example... Figure 26B The multiple anchoring barbs 156a shown are located on one side of the support 152, facing the opposite direction, while... Figure 26E In this configuration, the anchoring barbs are located on opposite sides of the support, facing the same direction. In another embodiment, as... Figure 26C and Figure 26D As shown, the anchoring barb 156b is contained within the thickness of the support 152, rather than, for example, as... Figure 26A and Figure 26B It is shown on the side of the support. Figure 26C The anchoring barb configuration shown in -D can be similar to... Figure 14A -C is formed as shown and as described above, with the anchor barb forming a 50s shape.

[0125] In other embodiments, in Figure 26E In the example shown in -H, the anchoring barb 156 may have different overall shapes and / or points, which can facilitate the insertion and retention of the anchoring barb within the vessel wall in a variety of clinical situations. Figure 26E The illustration shows a single forked barb 156c and a fishhook barb 156d positioned on opposite sides of the support 152 and facing the same direction. Figure 26F , Figure 26G and Figure 26H Further examples of anchoring barb designs are shown, in this case, a serrated barb 156e, a double-edged barb 156f, and a double-sided hook barb 156g. These barbs can be located on the side of the anchoring frame post and, as mentioned above, within the thickness of the post.

[0126] As described above, it may be desirable to configure the anchoring frame 150 such that it does not form coils that could interfere with the RC-WVM implant signal. As described above, one solution is the gap 166. In other embodiments, for example, where other design considerations may make discontinuous structures less preferable, such that the mechanical and electrical connections (e.g., crimped joints) of the anchoring frame wires are interlocked and in contact with each other, the ends of the wire terminals may be electrically insulated to prevent the formation of coils capable of coupling with a magnetic field. An example of such insulation is a polymer coating. In other embodiments, for example, where the anchoring frame may be formed from a laser-cut nitinol tube, this may require mechanical connections or adhesives that can physically and electrically separate the terminals of the nitinol frame using non-conductive adhesives (such as polymers, epoxy resins, or ceramic materials). Figure 27 This type of non-conductive connection is shown in cross-section. In this example, the end 170 of the anchoring frame 150 has an interlocking portion that can be bonded to a non-conductive adhesive 172, which also surrounds the connection to increase strength.

[0127] As previously discussed, the radial force applied by the RC-WVM implant should allow the sensor segment to move with the natural movement of the IVC as it expands and contracts due to changes in fluid volume. The anchoring frame 150 is configured to apply an outward radial force sufficient to ensure that the anchoring barbs 156 engage with the vessel wall to help prevent migration along the vessel without interfering with the movement and electrical performance of the RC-WVM sensor segment. Therefore, the radial force applied by the anchoring frame 150 can generally be equal to or greater than the radial force applied by the sensor segment of the RC-WVM implant to provide resistance to migration, while essentially isolating it from the lower radial force sensor segment via the isolation segment 159, which is configured to allow the IVC to expand and contract naturally in response to different fluid states.

[0128] The isolation segment 159 allows attachment between the sensor segment and the anchoring frame, but also allows the sensor segment and the anchoring frame to function independently of each other. Therefore, the RC-WVM sensor segment can contract and expand at its monitoring location within the blood vessel, independent of the expansion and contraction of the anchoring frame at its anchoring location within the blood vessel. One design consideration in selecting the configuration of the anchoring frame is that the radial force applied by the anchoring frame should be sufficient to prevent RC-WVM implant migration, but low enough not to dilate or open the blood vessel.

[0129] Figure 28 The illustration shows how changing the configuration—by varying the diameter of the anchor frame 150, the anchor frame width, the anchor frame thickness, the anchor frame shape, the crown diameter, the number of crowns, the anchor frame length, the material properties, the distance between the sensor segment and the anchor frame, and the overall length—adjusts or modifies the radial force of the anchor frame 150 to control the applied radial force. Another alternative to increasing the fixation of the RC-WVM implant is to provide anchor frames at both ends of the sensor segment, such as… Figure 21 As shown. Figure 28 An alternative anchoring frame 150a is shown, which has a relatively shorter strut length 152, more crowns 154 (here, 16 crowns instead of 8 in the previous embodiment), and a smaller crown diameter. The isolation section 159 is also longer, increasing the distance between the anchoring frame and the sensor section.

[0130] Figure 28The configuration of the anchoring frame 150a is chosen to target appropriate radial forces while minimizing areas of high strain concentration that could reduce fatigue life. Factors affecting the amount of radial force that the anchoring frame can apply without unduly impacting the sensor section include the distance between the anchoring barb 156 and the sensor section, which can be adjusted based on the positioning of the anchoring barb on the support 152 and / or by the length of the isolation section 159 that assists in isolation. In addition to varying the length of the isolation section 159, other adjustments include varying the thickness and / or the straightness relative to the curved section. For example, Figure 28 The image shows a straight anchoring isolation section 159, and in another example, a curved or S-shaped anchoring isolation section 159 is shown. Figure 24A It is shown in the middle.

[0131] In another alternative embodiment, the anchoring frame can be configured to intentionally break off and separate from the sensor segment over time. In this embodiment, for example, the connection point between the anchoring frame and the sensor segment in the isolation segment 159 is designed to be intentionally broken. The purpose of intentional breaking is to completely isolate the anchoring frame from the sensor segment after breaking. In this type of embodiment, the anchoring frame will secure the RC-WVM implant to prevent migration when initially deployed in a blood vessel. Over time, as the sensor segment embeds into the tissue, the risk of migration decreases. Thus, the function of the anchoring frame is no longer needed. Once no longer needed, this embodiment allows the anchoring frame to be disconnected from the device without surgery.

[0132] The material and design of the isolation segment 159 can be selected to provide different time periods for fracture to occur. For example, the geometry, design, movement, and materials of the sensor segment, isolation segment, and anchoring frame can be tuned to cause fatigue-induced fracture after / within a given time due to fatigue. Alternatively, fracture can be induced by external means. For example, ultrasound / RF can be used to induce fracture by disrupting the material or bond between the anchoring frame and the sensor segment at a predetermined frequency or energy. In another alternative embodiment, chemically induced fracture of the isolation segment 159 can be achieved using, for example, biodegradable polymers (e.g., PLA, PCL, PLGA, PLG) or other materials used as adhesives / connections between the anchoring frame and the RC-WVM implant frame. Chemically induced fracture utilizes the material properties of biodegradable polymers, which can degrade at controlled rates, including factors such as pH, temperature, the presence of microorganisms, and water.

[0133] In another alternative embodiment, the anchoring frame 150 may be made of a bioabsorbable / biodegradable material, such as that commonly used in bioabsorbable struts. Similar to other embodiments of anchoring frames, the purpose of a bioabsorbable anchoring frame is to help prevent migration. Again, the risk of migration is reduced as the sensor segment embeds into the tissue over time. Thus, the function of the anchoring frame is no longer needed. The material and design of the bioabsorbable anchoring frame can be selected for different absorption time periods.

[0134] The foregoing description is a detailed account of illustrative embodiments of the present invention. It should be noted that, in this specification and the claims appended thereto, unless specifically stated or otherwise indicated, connectives such as those used in the phrases “at least one of X, Y, and Z” and “one or more of X, Y, and Z” should mean that each item in the connective list may appear in the list in any number except every other item, or in any number combined with any other item or all other items, wherein each may also exist in any number. Applying this general rule, the connective phrases in the above examples, where the connective list consists of X, Y, and Z, should all include: one or more of X; one or more of Y; one or more of Z; one or more of X and one or more of Y; one or more of Y and one or more of Z; one or more of X and one or more of Z; and one or more of X, one or more of Y, and one or more of Z.

[0135] Various modifications and additions can be made without departing from the spirit and scope of the invention. Features of each of the various embodiments described above can be combined with features of other described embodiments as appropriate to provide multiple feature combinations in associated new embodiments. Furthermore, although some individual embodiments have been described above, the content described herein merely illustrates the application of the principles of the invention. Additionally, although specific methods herein may be shown and / or described as being performed in a particular order, the ordering will appear highly variable to those skilled in the art for the implementation of aspects of this disclosure. Therefore, this description is intended to be illustrative only and does not further limit the scope of the invention.

[0136] Exemplary embodiments have been disclosed above and illustrated in the accompanying drawings. Those skilled in the art will understand that various changes, omissions, and additions may be made to the specific disclosure herein without departing from the spirit and scope of the invention.

[0137] Various aspects of this disclosure may be implemented in one or more of the following embodiments:

[0138] 1) An anchoring system for a vascular implant, the anchoring system comprising:

[0139] A plurality of implant attachment segments are configured to attach to the vascular implant at spaced-apart locations, the attachment segments defining spaces between their structures to allow an adhesive to enter and attach to the vascular implant; and

[0140] At least one anchoring section is connected to each of the attachment sections, wherein at least one tissue-engaging anchoring barb is provided in each of the anchoring sections.

[0141] 2) The anchoring system according to 1) further includes an anchoring isolation section disposed between the attachment section and at least one anchoring section, the anchoring isolation section being configured to allow independent movement between the anchoring section and the attachment section.

[0142] 3) The anchoring system according to 1) or 2) includes a plurality of individual anchoring elements, each of the anchoring elements having an attachment section connected to one of the anchoring sections.

[0143] 4) The anchoring system according to 3), wherein each of the individual anchoring elements is formed of a flat sheet or tubular material, and the at least one tissue-engaged anchoring barb is cut from the surface of the material and bent outward.

[0144] 5) According to the anchoring system described in 1) or 2), the anchoring system further includes a plurality of anchoring segments connected by crown segments to form an anchoring frame with a flexible concentric zigzag structure.

[0145] 6) The anchoring system according to 5), wherein a crown section disposed at opposite ends of the anchoring section defines a first end and a second end of the anchoring frame, and at least one attachment section is connected to each crown section at at least one end of the anchoring frame.

[0146] 7) The anchoring system according to 5) or 6), wherein the frame is discontinuous, and one of the crown segments forms a slit crown, the slit crown having two crown segment members spaced apart by the gap and an attachment segment connected to each crown segment member.

[0147] 8) An anchor for a vascular implant comprising a tubular member formed by cutting and segmentation, the anchor comprising:

[0148] An anchoring section, comprising at least one outwardly extending tissue-engaging barb formed in the anchoring section by cutting and outwardly bending a portion of the anchoring section; and

[0149] An attachment segment, connected to the anchoring segment, configured to attach to the vascular implant, the attachment segment defining a space between the structures of the attachment segment to allow an adhesive to enter and attach to the vascular implant.

[0150] 9) The anchoring member according to 8) further includes an isolation section disposed between the anchoring section and the attachment section, the isolation section being configured to allow independent movement between the anchoring section and the attachment section.

[0151] 10) An anchoring frame for a vascular implant, the anchoring frame comprising a resilient concentric zigzag structure formed by a plurality of support segments interconnected by a crown segment, wherein:

[0152] The structure has two ends, wherein the crown section is disposed at one of the two ends and the support section is between the two ends;

[0153] At least a plurality of the support sections form an anchoring section having at least one tissue-engaging barb;

[0154] At least one attachment segment is connected to each crown segment at at least one of the ends of the structure; and

[0155] Each attachment segment includes an elongated member that defines a space between the structures of the attachment segments to allow an adhesive to enter and attach to the vascular implant.

[0156] 11) The anchoring frame according to 10) further includes an anchoring isolation section disposed between each attachment segment and each of the crown segments, the anchoring isolation section being configured to allow independent movement between the anchoring segment and the attachment segment.

[0157] 12) The anchoring frame according to 10) or 11), wherein the frame is electrically discontinuous, wherein non-conductive gaps are formed in the zigzag structure.

[0158] 13) The anchoring frame according to 12), wherein the non-conductive gap includes one of the crown segments forming a slit crown portion, the slit crown portion having two crown segment members spaced apart by the gap and an attachment segment connected to each crown segment member.

[0159] 14) An anchoring frame according to any one of 10)-13), wherein each tissue-engaging barb is disposed at an angle relative to the support section on the support section such that when the anchoring frame is deployed in the lumen of the vessel in a manner that contacts the lumen wall, the barb is positioned generally parallel to the direction of blood flow in the lumen of the vessel.

[0160] 15) An anchoring frame according to any one of 10)-14), wherein, when deployed in a lumen, the anchoring frame expands to contact the lumen wall, and the support segments are straight to allow each complete support segment and each coronary segment to be juxtaposed against the lumen wall for multiple lumen diameters in the case of a single-size anchoring frame.

[0161] 16) An anchoring system according to any one of 1)-7), an anchoring member according to any one of 8)-9), or an anchoring frame according to any one of 10)-15), wherein the attachment segment comprises alternating ridge and groove structures when the grooved region provides space for an adhesive to attach the implant between the ridge structures.

[0162] 17) An anchoring system according to any one of 1)-7), an anchoring element according to any one of 8)-9), or an anchoring frame according to any one of 10)-15), wherein the attachment section includes a series of holes formed along the attachment section.

[0163] 18) An anchoring system according to any one of 1)-7), an anchoring member according to any one of 8)-9), or an anchoring frame according to any one of 10)-15), wherein the attachment section includes a helical member having an inner diameter configured to be received on the outer diameter of the implant structure.

[0164] 19) The anchoring system, anchoring element, or anchoring frame according to 18), wherein the helical member is configured to engage the implant with an interference fit.

[0165] 20) An anchoring system, anchor, or anchoring frame according to any one of 1)-19), wherein the attachment segment includes a breakable connection to allow separation of the anchoring segment from the implant.

[0166] 21) The anchoring system, anchoring element, or anchoring frame according to 20), wherein the breakable connection is configured to self-separate after a predetermined time period.

[0167] 22) The anchoring system, anchoring element, or anchoring frame according to 20), wherein the breakable connection is configured to separate in response to externally guided energy.

[0168] 23) An anchoring system, anchor member, or anchoring frame according to any one of 1)-22), the anchoring system, anchor member, or anchoring frame further includes a recapture feature disposed opposite the attachment section, the recapture feature being configured to releasably engage a corresponding feature on a remote end of the deployment device.

[0169] 24) The anchoring element according to 23), wherein the recapture feature includes a portion of the anchoring section opposite the attachment section that is configured to have a protrusion or opening.

[0170] 25) The anchoring frame according to 23), wherein the recapture feature includes a recapture element extending from the crown section of the anchoring frame opposite the attachment section, the recapture element having a notch or opening capable of engaging with the distal end of the deployment device.

[0171] 26) A vascular implant adapted to be deployed and implanted in a patient's vascular system and positioned in a lumen of the vascular system in a manner that contacts the lumen wall, said implant comprising an anchoring system, a plurality of anchors or anchoring frames according to any one of 1)-25), said anchoring system, a plurality of anchors or anchoring frames being attached to a vascular device, wherein each attachment segment is attached to a separate segment of said vascular device.

[0172] 27) The vascular implant according to 26) further includes a reflux material that is melted into the space defined by the attachment segment to secure the attachment segment to the vascular device.

[0173] 28) The vascular implant according to 26) or 27), wherein:

[0174] The vascular device includes an elastic sensor configuration configured to expand and contract in size with the natural movement of the lumen wall;

[0175] The electrical properties of the elastic sensor structure vary in a known relationship with the dimensional expansion and contraction of the elastic sensor structure; and

[0176] The elastic sensor is configured to generate a wireless signal indicating the electrical properties, which can be wirelessly read outside the blood vessel lumen to determine the size of the blood vessel lumen.

[0177] 29) The vascular implant of claim 28), wherein the elastic sensor configuration includes an elastic concentric zigzag structure formed by a plurality of straight support segments interconnected by a coronal segment, wherein the straight segments are configured to allow each complete straight support segment and each coronal segment to be juxtaposed against the lumen wall for the plurality of lumen diameters in the case of a single-size elastic sensor configuration.

[0178] 30) The vascular implant according to 28) or 29), wherein:

[0179] The elastic sensor construction is configured and dimensionally designed to engage the cavity wall and to substantially permanently implant itself onto or within the cavity wall.

[0180] The elastic sensor configuration has a variable inductance, which is related to the dimensional expansion and contraction of the elastic sensor configuration along at least one dimension; and

[0181] When the elastic sensor configuration is excited by an energy source for the configuration, the elastic sensor configuration generates a signal that can be wirelessly read outside the patient, indicating the value of the at least one dimension, thereby allowing the size of the vascular lumen to be determined.

[0182] 31) The vascular implant according to any one of 28)-30), wherein the elastic sensor configuration includes a coil configured to engage at least two opposing points on the vascular lumen wall, the inductance of the coil varying based on the distance between the two opposing points corresponding to the distance between the points on the coil and the points on the lumen wall.

[0183] 32) The vascular implant according to 31), wherein the coil is rotationally symmetrical about the longitudinal axis.

[0184] 33) A vascular implant according to any one of 28)-32), wherein the elastic sensor configuration is configured to expand and contract along substantially any transverse axis of the blood vessel with the lumen wall, thereby altering the variable inductance.

[0185] 34) The vascular implant according to any one of 28)-33), wherein the elastic sensor configuration includes a resonant circuit whose resonant frequency varies with the variable inductance, and the signal is related to the resonant frequency.

[0186] 35) The vascular implant according to any one of 31)-34), wherein:

[0187] The coil includes a resonant circuit with an inductor and a capacitor having a defined resonant frequency, wherein the resonant frequency varies based on the distance between the at least two points; and

[0188] The coil is configured to be excited from outside the patient by a magnetic field directed at the coil.

[0189] 36) The vascular implant according to any one of 31)-35), wherein the coil is formed of Litz wire.

[0190] 37) A wireless vascular monitoring system comprising a vascular implant according to any one of 28)-36) and a patient external antenna ring, said patient external antenna ring comprising:

[0191] The base layer has sufficient length to form a discontinuous circumferential ring that completely surrounds the patient;

[0192] At least one continuous loop of antenna core wire disposed on the base layer, the length of the continuous loop being sufficient to extend substantially around the patient when the base layer is positioned around the patient;

[0193] A connection portion, the connection portion being used as a communication link between at least one continuous loop of the antenna core wire and the control system.

[0194] 38) The wireless vascular monitoring system according to 37) wherein at least one continuous loop of the antenna core wire has sufficient length such that the loop ends are substantially adjacent when the base layer is wrapped around the patient.

[0195] 39) A patient external antenna ring for a wireless vascular monitoring system, the patient external antenna ring comprising:

[0196] The base layer has sufficient length to form a discontinuous circumferential ring that completely surrounds the patient;

[0197] At least one continuous loop of the antenna core wire is disposed on the base layer, the length of the continuous loop being sufficient to extend substantially around the end of a substantially adjacent patient loop when the base layer is positioned around the patient;

[0198] A connection portion, the connection portion being used as a communication link between at least one continuous loop of the antenna core wire and the control system.

[0199] 40) An anchor for a wireless vascular monitoring implant, the anchor comprising:

[0200] An anchoring segment configured to engage with the vascular lumen wall within which the monitoring implant is placed, the anchoring segment including at least one outwardly extending barb; and

[0201] An attachment section is configured to attach to an elastic portion of the sensor construction, the attachment portion including a helical member sized to slide on the wire or coil portion of the monitoring implant in an interference fit, the helical portion also defining a space between the helices sufficient to accommodate adhesive therebetween.

[0202] 41) The anchoring member according to 40) further includes an isolation section disposed between the anchoring section and the attachment section, the isolation section being configured to at least partially mechanically isolate movement of the anchoring section relative to the attachment section.

[0203] 42) An anchoring member according to any one of 40)-41), wherein the adhesive comprises a polymeric reflow material.

[0204] 43) An anchoring member according to any one of 40)-42), wherein the helical member has an inner diameter that is dimensionally designed to produce a positional interference fit with the outer diameter of the coil portion of the monitoring implant.

[0205] 44) A method of manufacturing a wireless vascular implant, comprising:

[0206] A flexible frame construction is provided, the flexible frame construction being configured to present a desired shape for the implant in a free state;

[0207] Multiple coil wires are wound around the frame structure to form coils on the frame structure;

[0208] Connecting terminals are formed at the opposite ends of the coil wire;

[0209] Multiple anchors are placed on the coil formed on the frame structure, the anchors having helical sections configured to be received on the coil in an interference fit with the coil;

[0210] The anchor is bonded to the coil using an adhesive material that flows between the spaces in the spiral section; and

[0211] Attach the opposite terminals of the capacitor to the opposite connection terminals.

[0212] 45) The method of manufacturing a wireless vascular implant according to 44), wherein bonding the anchor includes placing a polymeric return tube over the helical segment on the coil and melting the return tube.

[0213] 46) An implant for positioning in a body cavity and engaging with the wall of the cavity, the implant comprising:

[0214] An implant body, the implant body including at least one wire component having an outer diameter; and

[0215] An anchoring element, the anchoring element including an attachment portion for attaching the anchoring element to the at least one line component, wherein the attachment portion includes a helical section defining an inner diameter dimensionally designed to fit into the outer diameter of the line component that engages with the helical section.

[0216] 47) The implant according to 46), wherein the spiral segment is dimensionally designed to form an interference fit with the outer diameter of the at least one linear component.

[0217] 48) The implant according to 47), wherein the implant further includes an adhesive material flowing between the open regions of the spiral segment.

[0218] 49) The implant according to 47) or 48), wherein the interference fit is a positional interference fit.

[0219] 50) An anchoring frame for a vascular implant, the anchoring frame comprising:

[0220] The flexible concentric zigzag structure is formed by multiple support segments connected to each other at acute angles through a rounded crown segment;

[0221] At least one tissue engagement barb is provided in the plurality of said support sections;

[0222] A device for attachment, used to attach the zigzag structure to a vascular implant; and

[0223] A non-conductive gap is formed in the zigzag structure, making the anchoring frame electrically discontinuous.

[0224] 51) The anchoring frame according to 50), wherein:

[0225] The elastic concentric zigzag structure has two ends, wherein the crown section is disposed at one of the two ends, and the support section is between the two ends;

[0226] The attachment means includes at least one attachment section, the at least one attachment section being connected to a plurality of crown sections at at least one end of the structure;

[0227] Each attachment segment includes an elongated member that defines a space between the structures of the attachment segments to allow an adhesive to enter and attach to the vascular implant.

[0228] 52) The anchoring frame according to 50) or 51), wherein the attachment device includes an anchoring isolation device for allowing independent movement between the resilient concentric zigzag structure and the implant attached to the resilient concentric zigzag structure.

[0229] 53) An anchoring frame according to any one of 50)-52), wherein the non-conductive gap includes one of the crown segments forming a slit crown portion, the slit crown portion having two crown segment members spaced apart by the gap and an attachment segment connected to each crown segment member.

[0230] 54) An anchoring frame according to any one of 50)-53), wherein, when deployed in a lumen, the anchoring frame expands to contact the lumen wall, and the support segment is straight to allow each complete support segment and each coronal segment to be juxtaposed against the lumen wall for multiple lumen diameters in the case of a single-size anchoring frame.

[0231] 55) An anchoring frame for a vascular implant, wherein, when the anchoring frame is deployed in a vascular lumen, the anchoring frame expands to contact the lumen wall, the anchoring frame comprising:

[0232] The flexible concentric zigzag structure is formed by multiple straight support segments connected to each other through a circular crown segment;

[0233] At least one tissue-engaging barb, said at least one tissue-engaging barb being disposed in the plurality of said support segments; and

[0234] A device for attachment, used to attach the zigzag structure to a vascular implant;

[0235] The straight configuration of the support segments allows each complete support segment and each coronary segment to be juxtaposed against the vessel lumen wall for multiple vessel lumen diameters within a single-size anchoring frame.

[0236] 56) According to the anchoring frame described in 55), wherein:

[0237] The elastic concentric zigzag structure has two ends, wherein the crown section is disposed at one of the two ends, and the support section is between the two ends;

[0238] The attachment means includes at least one attachment section connected to a plurality of crown sections at at least one end of the structure; and

[0239] Each attachment segment includes an elongated member that defines a space between the structures of the attachment segments to allow an adhesive to enter and attach to the vascular implant.

[0240] 57) A wireless vascular sensor configured to be implanted in a vascular lumen in contact with the lumen wall, the sensor comprising an elastic sensor configuration configured to expand and contract in size with natural movement of the lumen wall, wherein:

[0241] The elastic sensor configuration includes an elastic concentric zigzag structure formed by a plurality of straight support segments connected to each other by a circular coronal segment, wherein the straight support segments are configured to allow each complete straight support segment and each coronal segment to be juxtaposed against the lumen wall for multiple lumen diameters in the case of a single-size elastic sensor configuration;

[0242] The electrical properties of the elastic sensor structure vary in a known relationship with the dimensional expansion and contraction of the elastic sensor structure; and

[0243] The elastic sensor is configured to generate a wireless signal indicating the electrical properties, which can be wirelessly read outside the blood vessel lumen to determine the size of the blood vessel lumen.

[0244] 58) The wireless vascular monitoring implant according to 57), wherein:

[0245] The elastic sensor construction is configured and dimensionally designed to engage the cavity wall and to substantially permanently embed itself in or on the cavity wall.

[0246] The elastic sensor configuration has a variable inductance, which is related to the dimensional expansion and contraction of the elastic sensor configuration along at least one dimension; and

[0247] When the elastic sensor configuration is excited by an energy source for the configuration, the elastic sensor configuration generates a signal that can be wirelessly read outside the patient, indicating the value of the at least one dimension, thereby allowing the size of the vascular lumen to be determined.

[0248] 59) The wireless vascular monitoring implant according to any one of 57)-58), wherein the elastic sensor configuration includes a coil configured to engage at least two opposing points on the vascular lumen wall, the inductance of the coil varying based on the distance between the two opposing points corresponding to the distance between the points on the coil and the points on the lumen wall.

[0249] 60) A wireless vascular monitoring implant according to any one of 57)-59), wherein the elastic sensor configuration is configured to expand and contract along substantially any lateral axis of the blood vessel with the lumen wall, thereby altering the variable inductance.

[0250] 61) The wireless vascular monitoring implant according to any one of 57)-60), wherein the elastic sensor configuration includes a resonant circuit whose resonant frequency varies with the variable inductance, and the signal is related to the resonant frequency.

[0251] 62) The wireless vascular monitoring implant according to any one of 59)-61), wherein:

[0252] The coil includes a resonant circuit with an inductor and a capacitor having a defined resonant frequency, wherein the resonant frequency varies based on the distance between the at least two points; and

[0253] The coil is configured to be excited from outside the patient by a magnetic field directed at the coil.

Claims

1. An anchoring system for a vascular implant, the anchoring system comprising: Multiple implant attachment segments are configured to attach to the vascular implant at spaced-apart locations, the implant attachment segments defining a space between the structures of the implant attachment segments to allow an adhesive to enter and attach to the vascular implant; and Multiple anchoring segments, connected by crown segments, form an anchoring frame with a sinusoidal shape. At least one of the plurality of anchoring segments is connected to each of the implant attachment segments, wherein at least one tissue-engaging anchoring barb is provided in each of the anchoring segments.

2. The anchoring system of claim 1, further comprising an anchoring isolation section disposed between the implant attachment segment and the at least one anchoring segment, the anchoring isolation section being configured to allow independent movement between the anchoring segment and the implant attachment segment.

3. The anchoring system according to claim 1 or claim 2, wherein the anchoring system comprises a plurality of individual anchoring elements, each of the anchoring elements having an implant attachment segment connected to one of the anchoring segments.

4. The anchoring system according to claim 3, wherein, Each of the individual anchoring elements is formed from a flat sheet or tubular material, and the at least one tissue-jointing anchoring barb is cut from the surface of the flat sheet or tubular material and bent outward.

5. The anchoring system according to claim 1 or claim 2, wherein, The anchoring frame includes a flexible concentric zigzag structure.

6. The anchoring system according to claim 1 or claim 5, wherein, The crown section is disposed at opposite ends of the anchoring section to define a first end and a second end of the anchoring frame, and at least one attachment section is connected to each crown section at at least one end of the anchoring frame.

7. The anchoring system according to claim 1, claim 5, or claim 6, wherein, The frame is discontinuous, with one of the crown segments forming a slit crown portion having two crown segment members spaced apart by the gap and an attachment segment connected to each crown segment member.

8. The anchoring system according to any one of claims 1-7, wherein, When the grooved region provides space for the adhesive to attach to the implant between the ridged structures, the attachment segment includes alternating ridged and grooved structures.

9. The anchoring system according to any one of claims 1-7, wherein, The attachment section includes a series of holes formed along the attachment section.

10. The anchoring system according to any one of claims 1-7, wherein, The attachment section includes a helical member having an inner diameter configured to be received on the outer diameter of the implant structure.

11. The anchoring system according to claim 10, wherein, The helical member is configured to engage the implant with an interference fit.

12. The anchoring system according to any one of claims 1-7, wherein, The attachment segment includes a breakable connector to allow the anchoring segment to be separated from the implant.

13. The anchoring system according to claim 12, wherein, The breakable connection is configured to self-separate after a predetermined time period.

14. The anchoring system according to claim 12, wherein, The breakable connection is configured to separate in response to externally directed energy.

15. The anchoring system according to any one of claims 1-7, the anchoring system further comprising a recapture feature disposed opposite the attachment segment, the recapture feature being configured to releasably engage with a corresponding feature on a remote end of the deployment device.

16. An anchor for a vascular implant comprising a tubular member formed by cutting and segmentation, the anchor comprising: Multiple anchoring segments are connected by crown segments to form an anchoring frame having a sinusoidal form, each anchoring segment including at least one outwardly extending tissue-engaging barb formed in the anchoring segment by cutting and bending a portion of the anchoring segment outward; and A plurality of attachment segments are connected to the anchoring segment and configured to attach to the vascular implant at spaced-apart locations on the vascular implant. The plurality of attachment segments define a space between the structures of the plurality of attachment segments to allow an adhesive to enter and attach to the vascular implant.

17. The anchoring member of claim 16, further comprising an isolation section disposed between the anchoring section and the attachment section, the isolation section being configured to allow independent movement between the anchoring section and the attachment section.

18. The anchoring element according to any one of claims 16-17, wherein, When the grooved region provides space for the adhesive to attach to the implant between the ridged structures, the attachment segment includes alternating ridged and grooved structures.

19. The anchoring element according to any one of claims 16-17, wherein, The attachment section includes a series of holes formed along the attachment section.

20. The anchoring element according to any one of claims 16-17, wherein, The attachment section includes a helical member having an inner diameter configured to be received on the outer diameter of the implant structure.

21. The anchoring element according to claim 20, wherein, The helical member is configured to engage the implant with an interference fit.

22. The anchoring element according to any one of claims 16-17, wherein, The attachment segment includes a breakable connector to allow the anchoring segment to be separated from the implant.

23. The anchoring element according to claim 22, wherein, The breakable connection is configured to self-separate after a predetermined time period.

24. The anchoring element according to claim 22, wherein, The breakable connection is configured to separate in response to externally directed energy.

25. The anchoring member according to any one of claims 16-17, the anchoring member further comprising a recapture feature disposed opposite the attachment segment, the recapture feature being configured to releasably engage a corresponding feature on a remote end of the deployment device.

26. The anchoring element according to claim 25, wherein, The recapture feature includes a portion of the anchoring section that is configured to have a protrusion or opening opposite the attachment section.

27. An anchoring frame for a vascular implant, the anchoring frame comprising a resilient concentric zigzag structure formed by a plurality of support segments interconnected by a crown segment, wherein: The structure has two ends, wherein the crown section is disposed at one of the two ends and the support section is between the two ends; The plurality of said support sections form an anchoring section having at least one tissue-engaging barb; Multiple attachment segments, each attachment segment being connected to each crown segment at at least one of the ends of the structure; and Each attachment segment includes an elongated member that defines a space between the structures of the attachment segments to allow an adhesive to enter and attach to the vascular implant.

28. The anchoring frame of claim 27, further comprising an anchoring isolation section disposed between each attachment segment and each of the crown segments, the anchoring isolation section being configured to allow independent movement between the anchoring segment and the attachment segment.

29. The anchoring frame according to claim 27 or claim 28, wherein, The frame is electrically discontinuous, wherein non-conductive gaps are formed in the zigzag structure.

30. The anchoring frame according to claim 29, wherein, The non-conductive gap includes one of the crown segments forming a slit crown portion, the slit crown portion having two crown segment members separated by the gap and an attachment segment connected to each crown segment member.

31. The anchoring frame according to any one of claims 27-30, wherein, Each tissue-engaging barb is positioned at an angle relative to the support section on the support section, such that when the anchoring frame is deployed within the lumen in a manner that contacts the lumen wall, the barb is positioned generally parallel to the direction of blood flow within the lumen.

32. The anchoring frame according to claim 31, wherein, When deployed in a blood vessel lumen, the anchoring frame expands to contact the lumen wall, and the support segments are straight to allow each complete support segment and each coronary segment to be juxtaposed against the lumen wall for multiple blood vessel diameters in the case of a single-size anchoring frame.

33. The anchoring frame according to any one of claims 27-32, wherein, When the grooved region provides space for the adhesive to attach to the implant between the ridged structures, the attachment segment includes alternating ridged and grooved structures.

34. The anchoring frame according to any one of claims 27-32, wherein, The attachment section includes a series of holes formed along the attachment section.

35. The anchoring frame according to any one of claims 27-32, wherein, The attachment section includes a helical member having an inner diameter configured to be received on the outer diameter of the implant structure.

36. The anchoring frame according to claim 35, wherein, The helical member is configured to engage the implant with an interference fit.

37. The anchoring frame according to any one of claims 27-32, wherein, The attachment segment includes a breakable connector to allow the anchoring segment to be separated from the implant.

38. The anchoring frame according to claim 37, wherein, The breakable connection is configured to self-separate after a predetermined time period.

39. The anchoring frame according to claim 37, wherein, The breakable connection is configured to separate in response to externally directed energy.

40. The anchoring frame according to any one of claims 27-32, the anchoring frame further comprising a recapture feature disposed opposite the attachment segment, the recapture feature being configured to releasably engage with a corresponding feature on a remote end of the deployment device.

41. The anchoring frame according to claim 40, wherein, The recapture feature includes a recapture element extending from the crown section of the anchoring frame and opposite the attachment section, the recapture element having a notch or opening capable of engaging with the distal end of the deployment device.

42. A vascular implant adapted to be deployed and implanted in a patient's vascular system and positioned in a lumen of a blood vessel in a manner that contacts the lumen wall, said vascular implant comprising an anchoring system according to any one of claims 1-7, a plurality of anchors according to any one of claims 16-17, or an anchoring frame according to any one of claims 27-32, said anchoring system, said plurality of anchors, or said anchoring frame being attached to a vascular device, wherein, Each attachment segment is attached to a separate segment of the vascular device.

43. The vascular implant of claim 42, further comprising a reflux material melted into the space defined by the attachment segment to secure the attachment segment to the vascular device.

44. The vascular implant according to claim 42 or claim 43, wherein: The vascular device includes an elastic sensor configuration configured to expand and contract in size with the natural movement of the lumen wall; The electrical properties of the elastic sensor structure vary in a known relationship with the dimensional expansion and contraction of the elastic sensor structure; and The elastic sensor is configured to generate a wireless signal indicating the electrical properties, which can be wirelessly read outside the blood vessel lumen to determine the size of the blood vessel lumen.

45. The vascular implant according to claim 44, wherein, The elastic sensor configuration includes an elastic concentric zigzag structure formed by a plurality of straight support segments interconnected by a coronal segment, wherein the straight support segments are configured to allow each complete straight support segment and each coronal segment to be juxtaposed against the lumen wall for multiple lumen diameters in the case of a single-size elastic sensor configuration.

46. ​​The vascular implant according to claim 44 or 45, wherein: The elastic sensor construction is configured and dimensionally designed to engage the cavity wall and to substantially permanently implant itself onto or within the cavity wall. The elastic sensor configuration has a variable inductance, which is related to the dimensional expansion and contraction of the elastic sensor configuration along at least one dimension. and When the elastic sensor configuration is excited by an energy source for the configuration, the elastic sensor configuration generates a signal that can be wirelessly read outside the patient, indicating the value of the at least one dimension, thereby allowing the size of the vascular lumen to be determined.

47. The vascular implant according to claim 46, wherein, The elastic sensor configuration includes a coil configured to engage at least two opposing points on the cavity wall, the inductance of the coil varying based on the distance between the two opposing points corresponding to the distance between the points on the coil and the points on the cavity wall.

48. The vascular implant according to claim 47, wherein, The coil is rotationally symmetrical about the longitudinal axis.

49. The vascular implant according to any one of claims 47-48, wherein, The elastic sensor is configured to expand and contract along substantially any lateral axis of the blood vessel with the lumen wall, thereby altering the variable inductance.

50. The vascular implant according to any one of claims 47-49, wherein, The elastic sensor is constructed to include a resonant circuit whose resonant frequency varies with the variable inductor, and the signal is related to the resonant frequency.

51. The vascular implant according to any one of claims 47-50, wherein: The coil includes a resonant circuit with an inductor and a capacitor having a defined resonant frequency, wherein the resonant frequency varies based on the distance between the at least two points; and The coil is configured to be excited from outside the patient by a magnetic field directed at the coil.

52. The vascular implant according to any one of claims 47-51, wherein, The coil is formed from Litz wire.

53. A wireless vascular monitoring system comprising a vascular implant according to any one of claims 44-52 and a patient external antenna ring, said patient external antenna ring comprising: The base layer has sufficient length to form a discontinuous circumferential ring that completely surrounds the patient; At least one continuous loop of antenna core wire disposed on the base layer, the length of the continuous loop being sufficient to extend substantially around the patient when the base layer is positioned around the patient; A connection portion, the connection portion being used as a communication link between at least one continuous loop of the antenna core wire and the control system.

54. The wireless blood vessel monitoring system according to claim 53, wherein, At least one continuous loop of the antenna core wire has sufficient length such that the loop ends are substantially adjacent when the base layer is wrapped around the patient.

55. An anchoring frame for a vascular implant, the anchoring frame comprising: The flexible concentric zigzag structure is formed by multiple support segments connected to each other at acute angles through a rounded crown segment; At least one tissue engagement barb is provided in the plurality of said support sections; A device for attachment, used to attach the zigzag structure of the anchoring frame to the vascular implant; and A non-conductive gap is formed in the zigzag structure, making the anchoring frame electrically discontinuous; The attachment device includes at least one attachment section, which is connected to a plurality of crown sections at at least one end of the structure; and Each attachment segment includes an elongated member that defines a space between the structures of the attachment segments to allow an adhesive to enter and attach to the vascular implant.

56. The anchoring frame according to claim 55, wherein: The elastic concentric zigzag structure has two ends, wherein the crown section is located at one of the two ends, and the support section is located between the two ends.

57. The anchoring frame according to claim 55 or claim 56, wherein, The attachment device includes an anchoring isolation device for allowing independent movement between the resilient concentric zigzag structure and the implant attached to the resilient concentric zigzag structure.

58. The anchoring frame according to any one of claims 55-57, wherein, The non-conductive gap includes a crown segment forming a slit crown portion having two crown segment members spaced apart by the gap and an attachment segment connected to each crown segment member.

59. The anchoring frame according to any one of claims 55-58, wherein, When deployed in a blood vessel lumen, the anchoring frame expands to contact the lumen wall, and the support segments are straight to allow each complete support segment and each coronary segment to be juxtaposed against the lumen wall for multiple blood vessel diameters in the case of a single-size anchoring frame.

60. An anchoring frame for vascular implants, wherein, When the anchoring frame is deployed in the blood vessel lumen, the anchoring frame expands to contact the lumen wall, the anchoring frame comprising: The flexible concentric zigzag structure is formed by multiple straight support segments connected to each other through a circular crown segment; At least one tissue-engaging barb, said at least one tissue-engaging barb being disposed in the plurality of said support segments; and A device for attachment, used to attach the zigzag structure to a vascular implant; The straight configuration of the support segments of the anchoring frame allows each complete support segment and each coronary segment to be juxtaposed against the lumen wall for multiple vessel lumen diameters within a single-size anchoring frame; The attachment device includes at least one attachment section connected to a plurality of crown sections on at least one end of the structure of the anchoring frame; and Each attachment segment includes an elongated member that defines a space between the structures of the attachment segments to allow an adhesive to enter and attach to the vascular implant.

61. The anchoring frame according to claim 60, wherein: The elastic concentric zigzag structure of the anchoring frame has two ends, wherein the crown section of the anchoring frame is disposed at one of the two ends, and the support section of the anchoring frame is between the two ends.

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