Sensors for implantable medical systems and methods of manufacturing the same

Abstract

The present technology generally relates to a sensor assembly for an implantable medical device. In some embodiments, the sensor assembly includes a housing and a sensor subassembly including a first well member, a second well member, a pressure responsive element, a measurement component, and a coupling element. The first well member and the pressure responsive element can define a first cavity aligned with an aperture of the housing, and the second well member and the pressure responsive element can define a second cavity. The measurement component can be positioned in the second cavity. The coupling element can be disposed in the second cavity and in contact with each of the pressure responsive element and the measurement component. When the medical device is implanted within a patient, the measurement component can measure physiological parameters of the patient conveyed by the pressure responsive element and the coupling element.

Description

S ENSORS FOR IMPLANTABLE MEDICAL SYSTEMS ANDMETHODS OF MANUFACTURING THE SAMECROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] The present application claims the benefit of U.S. Provisional Patent Application No. 63 / 552,749, filed February 13, 2024, the disclosure of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present technology generally relates to implantable medical devices and / or medical systems and, in particular, to sensors for implantable medical devices and / or systems.BACKGROUND

[0003] Implantable devices and systems are utilized in modem medicine to provide a host of diagnostic and / or therapeutic benefits. For example, implantable shunting systems are widely used to treat a variety of patient conditions by shunting fluid from a first body region / cavity to a second body region / cavity. The flow of fluid through the shunting systems is primarily controlled by the pressure gradient across the shunt lumen and the geometry (e.g., size) of the shunt lumen. One challenge with conventional shunting systems is selecting the appropriate geometry of the shunt lumen for a particular patient. A lumen that is too small may not provide enough therapy to the patient, while a lumen that is too large may create new issues in the patient. Despite this, most conventional shunts cannot be adjusted once they have been implanted. Accordingly, once the system is implanted, the therapy provided by the shunting system cannot be adjusted or titrated to meet the patient’s individual needs.

[0004] Some implantable medical systems use sensors to measure physiological parameters (e.g., a shunt device that includes sensors to measure parameters in the first bodyregion and / or the second body region). Oftentimes, electrical components of sensors must be fluidically-isolated from anatomical regions in order to remain functional or accurate, and as such can be integrated into sealed (e.g., hermetically-sealed) housings, casings, and the like. For housings associated with pressure sensors, the housings generally can have a pressure responsive element at or near a surface that is affixed to the housing in a manner that is impermeable to fluid ingress. This pressure responsive element can be. for example, a diaphragm whosedeflection profile changes in response to changes in local physiological pressure. If the pressure responsive element is comprised of a material with suitable mechanical properties (e.g., flexural rigidity), it will sufficiently transfer pressure signals from outside of the housing to the interior of the housing without meaningful artifact (e.g., damping).

[0005] Challenges associated with systems described in the prior art can be related to manufacturing of appropriate sensor housings and related components. These challenges can include, for example, ensuring adequate coupling of a signal from outside of a housing to the electrical and / or mechanical components located internal to the housing that are sensitive to the signal (i.e., the '‘measurement component(s)” of the sensor apparatus). This coupling is generally accomplished using a coupling element, as elaborated upon below. Some approaches to pressure sensor assemblies described in the prior art have attempted to use a combined material as both a pressure responsive fluid-sealing element and as a pressure coupling element. These approaches, however, have been associated with limited success, as fluid ingress or diffusion over time can lead to degraded performance. Other approaches in the prior art use a separate diaphragm as a pressure responsive element and a fluid such as silicone oil as a coupling element that relays pressure signals produced in an external anatomical region (e.g., in the first body region or the second body region) to the measurement components within a housing. However, these solutions are often costly and difficult to manufacture and have been associated with unreliable performance, for example due to leaking of fluid out of the housing due to imperfections in the seal. Further, as sensor assemblies become smaller (e.g., to be compatible with percutaneously- delivered medical devices), the manufacturing difficulties associated with proper injection and / or encapsulation of a fluid coupling element escalate considerably.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed on illustrating clearly the principles of the present technology’. Furthermore, components can be shown as transparent in certain views for clarity of illustration only and not to indicate that the component is necessarily transparent. Components may also be shown schematically.

[0007] FIG. 1 is a schematic illustration of an interatrial shunting system including one or more sensors configured in accordance with select embodiments of the present technology.

[0008] FIG. 2A is a perspective view of a sensor assembly configured in accordance with select embodiments of the present technology.

[0009] FIG. 2B is a cross-sectional side view of the sensor assembly of FIG. 2A.

[0010] FIG. 3 is an enlarged cross-sectional side view of a sensor subassembly configured in accordance with select embodiments of the present technology.

[0011] FIG. 4 is an enlarged cross-sectional side view of another sensor subassembly configured in accordance with select embodiments of the present technology.

[0012] FIG. 5 is a flowchart illustrating a method of manufacturing a sensor assembly in accordance with select embodiments of the present technology.DETAILED DESCRIPTION

[0013] The present technology7is generally directed to medical systems including one or more sensors. In some embodiments, for example, the system includes a shunting element implantable into a patient at or adjacent to a septal wall of the patient. The shunting element, for example, can fluidly connect a left atrium and a right atrium of the patient to facilitate blood flow therebetween. In some embodiments, a size and / or shape of the shunting element is adjustable to alter the flow through the shunt. In some embodiments, for example, the shunting system can be configured to adjust the size and / or shape of the shunting element in response to a sensed (e.g., measured, detected, etc.) physiological parameter. For example, the system can include one or more sensors configured to sense a physiological parameter (e.g., temperature, pressure, etc.) in a first body chamber (e.g., the left atrium) and / or in a second body chamber (e.g., the right atrium), and the shunting element can be adjusted at least in part based on the sensed physiological parameter. In some embodiments, the sensors can include one or more capacitive sensors, piezoelectric sensors, piezoresistive sensors, Micro-electromechanical System (“MEMS”) sensors, and / or any other suitable sensor.

[0014] In some embodiments, a sensor assembly includes a housing or canister that is substantially impermeable to fluid. In some embodiments, the housing can at least partially enclose two coupling elements positioned on either side of a pressure responsive element (e.g., a diaphragm), and one or more measurement components interfacing one of the coupling elements. The other of the coupling elements can be exposed to an anatomical region (e.g., the first body chamber and / or the second body chamber) via, for example, an aperture in the housing. In some embodiments, the coupling elements may be chosen to be best suited for the parameterthe measurement component is designed to measure (e.g., pressure, temperature, etc ). The housing, the pressure responsive element, and / or the coupling elements can at least partially insulate or isolate the one or more measurement components from the anatomical region, while still allowing the one or more measurement components to sense physiological parameters. For example, the pressure responsive element and the pressure coupling elements can be configured to work in tandem to transmit a pressure (e.g., a left atrial pressure) from the anatomical region to the one or more measurement components of the system. In some embodiments, the coupling elements can be formed from elastomeric materials such as silicone gel, polydimethylsiloxane (PDMS), or another similar polymer. It is expected that medical systems including sensors that implement housings, pressure responsive elements, and / or coupling elements as described herein can reduce or prevent fluids (e.g., blood) in the first and / or second body cavities from disrupting or interfering with the operation of the one or more sensors. As explained in detail below, the disclosed sensor designs are further expected to improve the simplicity and lower the costs associated with manufacturing medical sensors, while providing assemblies that are expected to be both more accurate and robust in clinical settings.

[0015] The terminology used in the description presented below is intended to be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific embodiments of the present technology. Certain terms may even be emphasized below; however, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this Detailed Description section. Additionally, the present technology can include other embodiments that are within the scope of the examples but are not described in detail with respect to FIGS. 1-3.

[0016] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present technology. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features or characteristics may be combined in any suitable manner in one or more embodiments.

[0017] Reference throughout this specification to relative terms such as, for example, “substantially,” “approximately,” and “about” are used herein to mean the stated value plus or minus 10%.

[0018] As used herein, the terms “interatrial device’; “interatrial shunt device’; “IAD ”, “IASD”, “interatrial shunt”, and “shunt” are used interchangeably to refer to a device that, in at least one configuration, includes a shunting element that provides a blood flow between a first chamber (e.g., a left atrium of a heart) and a second chamber (e.g., a right atrium or coronary sinus of the heart) of a patient. Although described in terms of a shunt between the atria, namely the left and right atria, one will appreciate that the technology may be applied equally to devices positioned between other chambers and passages of the heart, between other parts of the cardiovascular system, or between other parts of the body. For example, any of the shunts described herein, including those referred to as “interatrial,” may nevertheless be used and / or modified to shunt between the left atria and the coronary sinus, or between the right pulmonary- vein and the superior vena cava. Moreover, while the disclosure herein primarily describes medical devices for shunting blood in the heart, the present technology can be readily adapted for medical devices used to shunt other fluids — for example, devices used for aqueous shunting or cerebrospinal fluid shunting. The present technology may also be adapted to a variety of implanted medical devices in addition to shunts. The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed present technology.A. Medical Systems Including Sensor(s)

[0019] FIG. 1 is a schematic illustration of an interatrial shunting system 100 (“system 100”) configured in accordance with embodiments of the present technology-. The system 100 includes a shunting element 102 defining a lumen 104 therethrough. The shunting element 102 can include a first end portion 103a positioned in a left atrium LA of a patient and a second end portion 103b positioned in a right atrium RA of the patient. Accordingly, when implanted in the septal wall S, the system 100 fluidly connects the left atrium LA and the right atrium RA via the lumen 104. When the system 100 is implanted within the patient to treat heart failure, blood generally flows through the lumen 104 in flow direction F (i.e., from the left atrium LA to the right atrium RA).

[0020] The system 100 can also include one or more sensors 140. For example, the system 100 can include a first sensor 140a positionable within the left atrium LA and a second sensor 140b positionable within the right atrium RA (collectively referred to as sensors 140). Further details regarding sensors configured for use with the system 100 or other medical systems are provided below with reference to FIGS. 2A and 2B. The sensors 140 can measure one or more physiologic parameters related to the system 100 or the environment proximate to the sensors140. For example, the first sensor 140a can be configured to measure left atrium LA pressure and the second sensor 140b can be configured to measure right atrium RA pressure. In some embodiments, the system 100 can further include a processor (not shown) configured to calculate a pressure differential between the left atrium LA and the right atrium RA, or other calculated parameters, based on the information measured by the sensor(s) 140. As described below, the system 100 may be adjusted based on the parameters measured by the sensor(s) 140 and / or the pressure differential calculated by the processor. Additional features of some embodiments of the sensors 140 useful in the system described herein are disclosed in International Patent Application Pub. No. WO 2021 / 113670, the disclosure of which is incorporated herein by reference in its entirety.

[0021] The system 100 also includes a flow control mechanism 150 (e.g., an actuation mechanism). The flow control mechanism 150 is configured to change a size, shape, or other characteristic of the shunting element 102 to change the flow of fluid through the lumen 104. In some embodiments, the flow control mechanism 150 can selectively change a size and / or shape of the lumen 104 to change the flow through the lumen 104. For example, the flow control mechanism 150 can be configured to selectively increase a diameter of the lumen 104 and / or selectively decrease a diameter of the lumen 104 in response to an input. In other embodiments, the flow control mechanism 150 is configured to otherwise affect a shape of the lumen 104. Accordingly, the flow control mechanism 150 can be coupled to the shunting element 102 and / or can be included within the shunting element 102. For example, in some embodiments the flow control mechanism 150 is part of the shunting element 102 and at least partially defines the lumen 104. In other embodiments, the flow control mechanism 150 is spaced apart from but operably coupled to the shunting element 102.

[0022] In some embodiments, at least a portion of the flow control mechanism 150 can comprise a shape memory material. The shape memory portion can include Nitinol, a shape memory' polymer, a pH-based shape memory' material, or any other suitable material configured to move or otherwise adjust as would be understood by one of skill from the description herein. The shape memory portion can be characterized by a curve that defines the amount of deformation the portion undergoes in response to a particular input (e.g., an applied stress). For example, the flow control mechanism 150 can include Nitinol element that is configured to change shape in response to exposure to energy, such as light and / or heat. In such embodiments, the flow control mechanism 150 can be selectively actuated by applying energy directly or indirectly to the Nitinol element. Additional embodiments of flow control mechanisms suitablefor use with the present technology are described in International Patent Application Pub. No. WO 2020 / 257530. the disclosure of which is incorporated herein by reference in its entirety’, and International Patent Application Pub. No. WO 2021 / 113670, the disclosure of which was previously incorporated by reference.

[0023] In some embodiments, the flow control mechanism 150 is coupled to a processor (not shown) that calculates the pressure differential between the left atrium and right atrium based, at least in part, on the measurements taken by the sensors 140. If the calculated pressure differential falls outside of a predetermined range, the processor can direct the flow control mechanism 150 to change the flow through the shunting element 102.

[0024] FIGS. 2A and 2B illustrate a perspective view and a cross-sectional side view; respectively, of a sensor assembly 200 (“assembly 200”) in accordance with select embodiments of the present technology’. The assembly 200 can be part of a stand-alone sensing system, part of an interatrial shunting system such as the system 100 of FIG. 1, or part of other suitable systems configured for implantation within a patient. In some embodiments, for example, the assembly 200 can be generally similar to, the same as, or included in (e.g., a component of) the first sensor 140a and / or the second sensor 140b of FIG. 1, and can measure one or more phy siologic parameters related to the environment proximate to the assembly 200.

[0025] Referring first to FIG. 2A, the assembly 200 includes a housing 210 (also referred to as a canister or vessel) having a first end portion 212a and a second end portion 212b, aheader subassembly 220 coupled to the first end portion 212a of the housing 210. and a sensor subassembly 230 disposed at least partially within the housing 210. In the illustrated embodiment, the housing 210 has a generally cylindrical shape and the header subassembly 220 has a generally domed shape. In other embodiments, how ever, the housing 210 and the header subassembly 220 can have other suitable shapes. In the illustrated embodiment, various portions of the housing 210 and the header subassembly 220 are rendered partially transparent for illustrative purposes only. The housing 210 can include an aperture 214 through which the sensor subassembly 230 can be at least partially exposed to the surrounding environment. The housing 210 and the header subassembly 220 can be formed from a material such a metal (e.g., titanium), a composite, polymer, a combination thereof, and / or any other suitable material. The housing 210 can be hermetically sealed (or substantially impermeable to fluid) to prevent fluid from leaking into the housing 210 and potentially damaging certain components of the sensorsubassembly 230 and / or affecting measurements taken by the sensor subassembly 230 during operation after implantation within a patient.

[0026] Referring next to FIG. 2B. the sensor subassembly 230 includes a first well member 232a and a second well member 232b (collectively referred to as “the well members 232”), a pressure responsive element 242 positioned between the first and second well members 232a, 232b, and a measurement component 250 disposed adjacent to and / or at least partially within the well members 232. In the illustrated embodiment, each of the well members 232 can have a tubular shape with a circular or elliptical cross-section. In other embodiments, however, the well members 232 can have other suitable shapes and / or configurations.

[0027] The second well member 232b can be fully disposed within the housing 210, and the first well member 232b can be coupled to the second well member 232b such that the well members 232 are aligned and the first well member 232a is at least partially exposed to the surrounding environment through the aperture 214 of the housing 210. A top portion of the first well member 232a can have a saddle shape such that the first well member 232a remains generally flush with the cylindrical shape of the housing 210, as shown in FIG. 2 A. The first well member 232a and the aperture 214 can form a fluid-tight seal therebetween, such as by also including O-rings, forming a threaded connection, forming an interference fit, etc.

[0028] The well members 232 can be formed from a material such a metal (e.g., titanium), a composite, polymer, a combination thereof, and / or any other suitable material. As shown in FIG. 2B, in some embodiments, a cross-sectional dimension DI (e.g.. diameter, major diameter, minor diameter) of the well members 232 can be at least 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, or between 2-6 mm. In some embodiments, a combined length D2 of the well members 232 can be at least 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, or between 0.5-6 mm. In some embodiments, the first and second well members 232a, 232b are integrally formed.

[0029] As shown in FIG. 2B, the pressure responsive element 242 can be attached between, coupled between, or otherwise integrated with the first and second well members 232a, 232b. In some embodiments, the pressure responsive element 242 can be a very thin diaphragm having low flexural rigidity and whose deflection profile changes in response to changes in local pressure. The pressure responsive element 242 can be formed from a material such a metal (e.g., titanium), a composite, polymer, a combination thereof, and / or any other suitable material. In some embodiments, the thickness of the pressure responsive element 242 is no more than 50 pm, 40 pm, 30 pm, 20 pm, 10 pm, or betw een 10-50 pm.

[0030] The sensor subassembly 230 can further include a first coupling element 240a disposed in the cavity defined by the first well member 232a and the pressure responsive element 242, and a second coupling element 240b disposed in the cavity defined by the second well member 232b and the pressure responsive element 242. Accordingly, the first coupling element 240a can be directly exposed to the surrounding environment through the aperture 214 of the housing 210, and the second coupling element 240b can at least partially cover, contact, encapsulate, or otherwise interface with the measurement component 250. The first and second coupling elements 240a, 240b can be formed from a material such as a silicone elastomer (e.g., polydimethylsiloxane (PDMS), silicone gel), other elastomeric material, or another suitable material. The first and second coupling elements 240a, 240b can be formed from the same material or different materials. The size (e.g.. volume) and / or the shape of the first and second coupling elements 240a, 240b can be selected based on the parameter the measurement component 250 is designed to measure (e.g., pressure, temperature, etc.), the location at which the assembly 200 is implanted, and / or other factors. For example, in some embodiments, the first well member 232a is filled such that the first coupling element 240a reaches the top of the first well member 232a. In other embodiments, the first well member 232a is only partially filled such that the first coupling element 240a does not reach the top of the first well member 232a.

[0031] The first coupling element 240a can be configured to transmit or convey one or more physiological parameters from the surrounding environment (e.g., the anatomical region, the left atrium LA, the right atrium RA, etc.) to the pressure responsive element 242. The pressure responsive element 242 can be configured to transmit or convey the one or more physiological parameters from the first coupling element 240a to the second coupling element 240b. The second coupling element 240b can be configured to transmit or convey the one or more physiological parameters from the pressure responsive element 242 to the measurement component 250. In other words, the first and second coupling elements 240a. 240b and the pressure responsive element 242 work in tandem to reliably and accurately convey physiological parameters from the surrounding environment to the measurement component 250.

[0032] The first and second coupling elements 240a, 240b can have a high bulk modulus such that the first and second coupling elements 240a, 240b are generally resistant to compression (e.g., in response to a pressure in the surrounding environment). For example, the first and second coupling elements 240a, 240b can have a bulk modulus K of at least 0.5 megapascals (MPa), 1 MPa, 2 MPa, 5 MPa. 10 MPa, 20 MPa, 50 MPa. 100 MPa, 1 gigapascals (GPa), 2 GPa, or any amount therebetween. In some embodiments, the first and second couplingelements 240a, 240b can have a hardness, as measured using the Shore hardness scale, of at least OOO. 0050, OOIOO, AO, A10, A20, A30, A40. A50, or any amount therebetween.

[0033] The bulk modulus of silicone elastomers (such as silicone gel) is typically less than the bulk modulus of the silicone oils used in conventional (e.g., larger, non-medical) sensor assemblies described in the prior art. Accordingly, one skilled in the art may generally expect that silicone elastomers have reduced viability as coupling elements and / or transmissive materials due to this difference in compressibility. Further, one could expect the use of a solid material coupling element (as opposed to a fluid or gas) could have further detrimental impact on the viability of the sensors due to challenges related to the coupling of solid components with measurement components. However, as described in more detail below, sensors configured in accordance with the present technology overcome these challenges and enable a silicone elastomer material to be utilized as a transmissive material without affecting the performance and / or accuracy of the sensors.

[0034] An unexpected finding associated with embodiments of the present technology configured to measure a pressure signal is that when used in conjunction with a very thin, low flexural rigidity pressure responsive element (e.g., the pressure responsive element 242), elastomeric coupling elements with a relatively lower bulk modulus (compared to a silicone oil) can effectively convey a pressure signal accurately from a region external to a housing (e.g.. an anatomical region such as a heart chamber) to a measurement component internal to the housing.

[0035] As described above, a further challenge to the viability of sensors using solid (e.g., elastomeric) coupling elements is an ability to manufacture such a component in a way that enables reliable functionality'. More specifically, it can be difficult to ensure that a solid coupling element makes sufficient and intimate contact with measurement component(s) of a sensor apparatus without introducing voids, gas bubbles, and / or other irregularities or disturbances that can introduce biases, artifacts, and / or other unwanted degradations to a conveyed signal. As disclosed in more detail below, the present technology overcomes this challenge with a novel manufacturing method aimed at depositing a solid coupling element in a manner such that it can cover, contact, or encapsulate a measurement component without voids, gas bubbles, and / or other irregularities.

[0036] In embodiments in which the first and second coupling elements 240a, 240b are composed of an elastomer (such as silicone gel), the first and second coupling elements 240a, 240b can be formed by depositing (e.g., pouring) the elastomer material into the cavities definedby the well members 232 and the pressure responsive element 242 when the elastomer material is in a liquid state where it has not yet been cured, hardened, etc., and allowing the elastomer material to cure or harden for a predetermined amount of time. For example, the predetermined amount of time can be at least 1 minute, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 45 minutes, 1 hour, 1 day, or any other amount of time. Such a method enables the elastomer material, while in its liquid state, to completely wet and form an intimate, void-free contact with the pressure responsive element 242 and the measurement component 250. Such a method also enables this intimate, void-free contact to be preserved after the elastomer material cures or hardens to form the first and second coupling elements 240a, 240b. If the elastomer material / first and second coupling elements 240a, 240b w ere to be applied in a cured or hardened state, said intimate contact would not be formed, and any dimensional differences between the mating surface of the cured or hardened first and second coupling elements 240a, 240b and the mating surfaces of the pressure responsive element 242 and / or the measurement component 250 would form voids. Maintaining such void-free contact is important to the pressure transmitting function of the first and second coupling elements 240a, 240b. as otherwise, pressure applied to the first and second coupling elements 240a. 240b (e.g., by the surrounding environment, by the pressure responsive element 242) would simply force the first and second coupling elements 240a, 240b into the void(s) rather than conveying the pressure to the measurement component 250. In other embodiments, however, the first and second coupling elements 240a, 240b can be formed using other suitable processes or techniques known to one of skill in the art.

[0037] The measurement component 250 can be positioned to sense one or more physiological parameters (e.g., pressure, temperature, etc.) conveyed from the surrounding environment by the first and second coupling elements 240a, 240b and the pressure responsive element 242. The measurement component 250 can include one or more capacitive sensors, piezoelectric sensors, piezoresistive sensors, MEMS sensors, and / or any other suitable sensor. In the illustrated embodiment, for example, the measurement component 250 includes a platform 252 (e.g., a circuit board) that can be coupled (e.g., via epoxy or other adhesives) to the second well member 232b to form a seal to contain the second coupling element 240b. In some embodiments, the measurement component 250 is prefilled with the material of the second coupling element 240b prior to assembly of the sensor subassembly 230.

[0038] FIG. 3 is an enlarged cross-sectional side view of a sensor subassembly 330 configured in accordance with select embodiments of the present technology. It is appreciated that the sensor subassembly 330 can be an example of the sensor subassembly 230 of FIGS. 2Aand 2B, and that similarly numbered components can be identical or similar in structure and / or function.

[0039] The sensor subassembly 330 can include a first well member 332a and a second well member 332b (collectively referred to as “the well members 332”). a pressure responsive element 342 positioned between the first and second well members 332a, 332b, and a measurement component 350 (e.g., a sensor) disposed adjacent to and / or at least partially within the second well member 332b. In the illustrated embodiment, the sensor subassembly 330 also includes a first coupling element 340a disposed in the cavity defined by the first well member 332a and the pressure responsive element 342, and a second coupling element 340b disposed in the cavity defined by the second well member 332b and the pressure responsive element 342. Each of the coupling element 340a and the second coupling element 340b can be disposed adjacent to and in contact with the pressure responsive element 342. In particular, the first coupling element 340a forms a curved exposed surface. The cross-section of the curved exposed surface of the first coupling element 340a can be parabolic, hyperbolic, circular, or otherwise curved. In some embodiments, the first coupling element 340a can have aflat, irregular, or other exposed surface shape.

[0040] In some embodiments, the sensor subassembly 330 further includes a covering 360 at least partially enclosing the sensor subassembly 330 (e.g.. and the sensor assembly that the sensor subassembly 330 is part of). The covering 360 can be composed of a semi-permeable or permeable material (e g., ePTFE). As shown, the shape of the covering 360 may track the shape of the first coupling element 340a, and may move therewith. Additional details regarding coverings are provided in U.S. Provisional Patent Application No. 63 / 554,364, filed February- 16, 2024. the disclosure of which is incorporated herein by reference in its entirety.

[0041] Compared to the first coupling element 240a of FIG. 2B, the first coupling element 340a occupies a smaller volume of the cavity defined by the first well member 332a and the pressure responsive element 342. Thus, FIG. 3 illustrates that the size (e.g., volume) and / or shape of the first coupling element 340a can be varied according to, e.g., desired sensor parameters. For example, if the first coupling element 340a is excessively attenuating the pressure signal, the thickness and / or shape of the first coupling element 340a can be altered accordingly (e.g., the thickness can be reduced). As another example, if too much of the patient’s blood is entering the remaining portion of the first well member 332a not occupied by the first coupling element 340a (e.g., due to the permeability of the covering 360) and pooling therein, leading to heightened riskof thrombus or other conditions, the thickness and / or shape of the first coupling element 340a can be altered accordingly (e.g., the thickness can be increased). In some embodiments, the first coupling element 340a can occupy no more than 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%, or 5-80% of the volume of the cavity defined by the first well member 332a and the pressure responsive element 342.

[0042] Furthermore, in some embodiments, the distance D3 between the pressure responsive element 342 and the measurement component 350 can be varied according to, e.g., desired sensor parameters. For example, the second coupling element 340b may be subject to thermal fluctuations and consequently thermally expand or contract. Such volumetric fluctuations of the second coupling element 340b can, in some circumstances, compromise the pressure signal transmitted from the pressure responsive element 342 to the measurement component 350. Accordingly, reducing the distance D3 can reduce the volume of the second coupling element 340b positioned between the pressure responsive element 342 and the measurement component 350, and thereby mitigate the effect of such volumetric fluctuations.

[0043] FIG. 4 is an enlarged cross-sectional side view of another sensor subassembly 430 configured in accordance with select embodiments of the present technology. It is appreciated that the sensor subassembly 430 can be an example of the sensor subassembly 230 of FIGS. 2A and 2B, and that similarly numbered components can be identical or similar in structure and / or function.

[0044] The sensor subassembly 430 can include a first well member 432a and a second well member 432b (collectively referred to as “the well members 432”), a pressure responsive element 442 positioned between the first and second well members 432a, 432b, and a measurement component 450 (e.g., a sensor) disposed adjacent to and / or at least partially within the second well member 432b. In the illustrated embodiment, the sensor subassembly 430 also includes a coupling element 440 disposed in the cavity defined by the second well member 432b and the pressure responsive element 442. However, compared to the sensor subassembly 230 of FIGS. 2A and 2B or the sensor subassembly 330 of FIG. 3, the sensor subassembly 430 of FIG. 4 does not include a coupling element in the cavity defined by the first well member 432a and the pressure responsive element 442. In some embodiments, the sensor subassembly 430 further includes a covering 460. As shown, the shape of the covering 460 can may track the shape of the cavity defined by the first well member 432a and the pressure responsive element 442, and move with the pressure responsive element 442.

[0045] As discussed above with reference to FIG. 3, the size and / or shape of the first coupling element can be varied to balance different factors (e.g., signal attenuation, risk of thrombus). Thus, the sensor subassembly 430 represents an embodiment aiming to remove all signal attenuation caused by, e.g., the first coupling element 340a by removing the first coupling element entirely. It will be appreciated that the decision whether to use the sensor subassembly 230, the sensor subassembly 330, the sensor subassembly 430, or other embodiment can depend on. e.g., the needs and particular characteristics of the patient, other sensor parameters, and / or the like.

[0046] Referring to FIGS. 2B-4 together, individual ones of the coupling elements can be composed of a silicone elastomer (e.g., polydimethylsiloxane (PDMS), silicone gel), other elastomeric material(s), or another suitable material. For example, the coupling element exposed to the environment (e.g.. the first coupling element 240a) can be composed of a low-durometer silicone (e.g., no more than 40, 30, 20. or 10 Shore A), as a softer material may enable more accurate pressure readings. As another example, the coupling element internal to the sensor assembly (e.g., the second coupling element 240b) can be composed of a two-part silicone to ensure that the material cures properly (e.g., a one-part silicone may have a higher chance of not curing as intended).B. Methods of Manufacturing Sensor Assemblies

[0047] FIG. 5 is a flowchart illustrating a method 500 of manufacturing a sensor assembly in accordance with an embodiment of the present technology. The method 500 can be used to manufacture the assembly 200 (FIGS. 2A and 2B) or other sensor assemblies. Sensor assemblies manufactured via the method 500 can be part of a stand-alone sensing system, part of an interatrial shunting system, or part of other suitable systems configured for implantation within a patient.

[0048] Beginning at block 502, the method 500 can include disposing a pressure responsive element (e.g., the pressure responsive element 242) between a first well member (e.g., the first well member 232a) and a second well member (e.g., the second well member 232b. In some embodiments, the first and second well members are made from a metal (e.g., titanium) tube having the desired cross-sectional shape and size, such as by cutting the tube to desired lengths. In some embodiments, the pressure responsive element can be formed by stamping a metal (e.g., titanium) foil with a desired thickness to the desired shape and size.

[0049] At block 504, the method 500 can include filling a first cavity defined by the first well member and the pressure responsive element with a first elastomer material. The method 500 continues at block 506 with filling a second cavity defined by the second well member and the pressure responsive element with a second elastomer material. The method 500 can include, at block 508, disposing a measurement component (e.g., the measurement component 250) at least partially in the second elastomer material. At block 510, the method 500 can then include allowing the first elastomer material to cure into a first coupling element (e.g., the first coupling element 240a) and the second elastomer material to cure into a second coupling element (e.g., the second coupling element 240b).

[0050] In some embodiments, the method 500 can also include, prior to disposing the measurement component at least partially in the second elastomer material, pre-filling the measurement component with the second elastomer material. Doing so can ensure that the measurement component is properly filled with the second elastomer material compared to, for example, relying on the second elastomer material in the second cavity7to seep into the measurement component. Removing any gaps or voids (e.g., air bubbles) in the measurement component can be critical to proper functioning of the measurement component.

[0051] In some embodiments, the method 500 can also include coupling the first well member to the second well member, such as via welding (e.g., laser welding) or another suitable technique. In some embodiments, the method 500 can also include coupling the second well member to the measurement component, such as via adhesives (e.g., epoxy). In some embodiments, the method 500 can also include enclosing the first well member, the second well member, the measurement component, the first coupling element, and the second coupling element inside a housing (e.g., the housing 210). The housing can include an aperture, and the first well member can be positioned at least partially in the aperture.

[0052] Sensors including coupling elements configured in accordance with embodiments of the present technology represent an improvement over traditional sensors that include silicone oil or other fluids. For example, referring again to FIGS. 2A and 2B together, the assembly 200 with the first and second coupling elements 240a, 240b sandwiching the pressure responsive element 242 and the second coupling element 240b interfacing the measurement component 250 is expected to be less costly to produce and easier to manufacture than traditional sensors. Further, as noted previously, sensor assemblies configured in accordance with the presenttechnology are expected to be both more accurate and robust in clinical settings than conventional devices.C. ExamplesThe present technology is illustrated, for example, according to various aspects described below as numbered examples (1 , 2, 3, etc.) for convenience. These are provided as examples and do not limit the present technology. It is noted that any of the dependent examples may be combined in any combination, and placed into a respective independent example. The other examples can be presented in a similar manner.1. A sensor assembly for an implantable medical device, the sensor assembly comprising: a housing having an aperture; and a sensor subassembly at least partially enclosed by the housing, the sensor subassembly comprising: a first well member positioned at the aperture of the housing; a second well member aligned with the first well member; a pressure responsive element disposed between the first well member and second well member, wherein the first well member and the pressure responsive element define a first cavity aligned with the aperture, and wherein the second well member and the pressure responsive element define a second cavity; a measurement component positioned in the second cavity; and a coupling element disposed in the second cavity and in contact with each of the pressure responsive element and the measurement component. wherein, when the medical device is implanted within a patient, the measurement component is configured to measure one or more physiological parameters of the patient conveyed by the pressure responsive element and the coupling element.2. The sensor assembly of example 1 wherein the coupling element is a second coupling element, and wherein the sensor subassembly further comprises a first coupling element disposed in the first cavity and in contact with the pressure responsive element.3. The sensor assembly of example 2 wherein each of the first coupling element and the second coupling element is composed of a silicone gel material.4. The sensor assembly of example 2 or example 3 wherein the first coupling element has a hardness no more than 20 Shore A.5. The sensor assembly of any of examples 2-4 wherein the first coupling element occupies no more than 50% of the first cavity.6. The sensor assembly of any of examples 2-5 wherein the first coupling element has a parabolic exposed surface facing the aperture.7. The sensor assembly of any of examples 1-6 wherein the coupling element is composed of a 2-part silicone gel material.8. The sensor assembly of any of examples 1-7 wherein the pressure responsive element is composed of titanium and has a thickness of no more than 30 pm.9. The sensor assembly of any of examples 1-8 wherein the measurement component includes a MEMS sensor.10. The sensor assembly of any of examples 1-9 further comprising a covering at least partially enclosing the housing and covering the aperture, wherein the covering is composed of ePTFE.11. The sensor assembly of any of examples 1-10 wherein the medical device comprises an interatrial shunt configured to be implanted within a heart of the patient.12. The sensor assembly of any of examples 1-11 wherein the one or more physiological parameters include a left atrial pressure and / or a right atnal pressure of the patient.13. A method of manufacturing a sensor assembly for an implantable medical device, the method comprising:disposing a pressure responsive element between a first well member and a second well member, wherein the first well member and the pressure responsive element define a first cavity aligned with an aperture of a housing of the sensor assembly, and wherein the second well member and the pressure responsive element define a second cavity; disposing a measurement component at least partially in the second cavity; filling the second cavity with an elastomer material such that the elastomer material is in contact with each of the pressure responsive element and the measurement component; and allowing the elastomer material to cure into a coupling element.14. The method of example 13 wherein the elastomer material is a second elastomer material, wherein the coupling element is a second coupling element, and wherein the method further comprises: filling the first cavity with a first elastomer material such that the first elastomer material is in contact with the pressure responsive element; and allowing the first elastomer material to cure into a first coupling element.15. The method of example 13 or example 14 wherein filling the second cavity with the elastomer material comprises filling the second cavity with a 2-part silicone gel material.16. The method of any of examples 13-15, further comprising: welding the first well member to the second well member; and coupling the second well member to the measurement component via adhesives.17. The method of any of examples 13-16, further comprising enclosing the first well member, the second well member, and the measurement component inside a housing, wherein disposing the pressure responsive element comprises aligning each of the first well member, the second well member, and the pressure responsive element with an aperture of the housing.18. A sensor subassembly, comprising: a first well member; a second well member aligned with the first well member;a pressure responsive element disposed between the first well member and second well member, wherein the first well member and the pressure responsive element define a first cavity aligned with the aperture, and wherein the second well member and the pressure responsive element define a second cavity; a measurement component positioned in the second cavity; and a coupling element disposed in the second cavity and in contact with each of the pressure responsive element and the measurement component, wherein, when the sensor subassembly is implanted within a patient, the measurement component is configured to measure one or more physiological parameters of the patient conveyed by the pressure responsive element and the coupling element.19. The sensor subassembly of example 18 wherein the coupling element is a second coupling element, and wherein the sensor subassembly further comprises a first coupling element disposed in the first cavity and in contact with the pressure responsive element.20. The sensor subassembly of example 19 wherein each of the first coupling element and the second coupling element is composed of a silicone gel material.Conclusion

[0053] Embodiments of the present disclosure may include some or all of the following components: a battery, supercapacitor, or other suitable power source; a microcontroller, FPGA, ASIC, or other programmable component or system capable of storing and executing software and / or firmware that drives operation of an implant; memory such as RAM or ROM to store data and / or software / firmware associated with an implant and / or its operation; wireless communication hardware such as an antenna system configured to transmit via Bluetooth, WiFi, or other protocols known in the art; energy harvesting means, for example a coil or antenna which is capable of receiving and / or reading an externally-provided signal which may be used to power the device, charge a battery, initiate a reading from a sensor, or for other purposes. Embodiments may also include one or more sensors, such as pressure sensors, impedance sensors, accelerometers, force / strain sensors, temperature sensors, flow sensors, optical sensors, cameras, microphones or other acoustic sensors, ultrasonic sensors, ECG or other cardiac rhythm sensors, SpCh and other sensors adapted to measure tissue and / or blood gas levels, blood volume sensors, and other sensors known to those who are skilled in the art. Embodiments may includeportions that are radiopaque and / or ultrasonically reflective to facilitate image-guided implantation or image guided procedures using techniques such as fluoroscopy, ultrasonography, or other imaging methods. Embodiments of the system may include specialized delivery catheters / sy stems that are adapted to deliver an implant and / or cany7out a procedure. Systems may include components such as guidewires, sheaths, dilators, and multiple delivery7catheters. Components may be exchanged via over- the- wire, rapid exchange, combination, or other approaches.

[0054] The above detailed description of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise forms disclosed above. Although specific embodiments of, and examples for, the technology7are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology as those skilled in the relevant art will recognize. For example, although steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments. For example, although this disclosure has been written to describe devices that are generally described as being used to create a path of fluid communication between the left atrium and right atrium, the left ventricle and the right ventricle, or the left atrium and the coronary sinus, it should be appreciated that similar embodiments could be utilized for shunts between other chambers of heart or for shunts in other regions of the body.

[0055] To the extent any material incorporated herein by reference conflicts with the present disclosure, the present disclosure controls. From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Where the context permits, singular or plural terms may also include the plural or singular term, respectively.

[0056] Unless the context clearly requires otherwise, throughout the description and the examples, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof, means any connection or coupling, either direct or indirect, between two or more elements; the coupling of connection between the elements can be physical, logical, or a combination thereof.Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. As used herein, the phrase “and / or” as in “A and / or B” refers to A alone, B alone, and A and B. Additionally, the term “comprising” is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and / or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with some embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology7. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.

Claims

CLAIMSWhat is claimed is:

1. A sensor assembly for an implantable medical device, the sensor assemblycomprising: a housing having an aperture; and a sensor subassembly at least partially enclosed by the housing, the sensor subassembly comprising: a first well member positioned at the aperture of the housing; a second well member aligned with the first well member; a pressure responsive element disposed between the first well member and second well member, wherein the first well member and the pressure responsive element define a first cavity aligned with the aperture, and wherein the second well member and the pressure responsive element define a second cavity; a measurement component positioned in the second cavity; and a coupling element disposed in the second cavity and in contact with each of the pressure responsive element and the measurement component. wherein, when the medical device is implanted within a patient, the measurement component is configured to measure one or more physiological parameters of the patient conveyed by the pressure responsive element and the coupling element.

2. The sensor assembly of claim 1 wherein the coupling element is a second coupling element, and wherein the sensor subassembly further comprises a first coupling element disposed in the first cavity and in contact with the pressure responsive element.

3. The sensor assembly of claim 2 wherein each of the first coupling element and the second coupling element is composed of a silicone gel material.

4. The sensor assembly of claim 2 wherein the first coupling element has a hardness no more than 20 Shore A.

5. The sensor assembly of claim 2 wherein the first coupling element occupies no more than 50% of the first cavity.

6. The sensor assembly of claim 2 wherein the first coupling element has a parabolic exposed surface facing the aperture.

7. The sensor assembly of claim 1 wherein the coupling element is composed of a 2-part silicone gel material.

8. The sensor assembly of claim 1 wherein the pressure responsive element is composed of titanium and has a thickness of no more than 30 pm.

9. The sensor assembly of claim 1 wherein the measurement component includes a MEMS sensor.

10. The sensor assembly of claim 1 further comprising a covering at least partially enclosing the housing and covering the aperture, wherein the covering is composed of ePTFE.

11. The sensor assembly of claim 1 wherein the medical device comprises an interatrial shunt configured to be implanted within a heart of the patient.

12. The sensor assembly of claim 1 wherein the one or more physiological parameters include a left atrial pressure and / or a right atrial pressure of the patient.

13. A method of manufacturing a sensor assembly for an implantable medical device, the method comprising: disposing a pressure responsive element between a first well member and a second well member, wherein the first well member and the pressure responsive element define a first cavity aligned with an aperture of a housing of the sensor assembly, and wherein the second well member and the pressure responsive element define a second cavity; disposing a measurement component at least partially in the second cavity;filling the second cavity with an elastomer material such that the elastomer material is in contact with each of the pressure responsive element and the measurement component; and allowing the elastomer material to cure into a coupling element.

14. The method of claim 13 wherein the elastomer material is a second elastomer material, wherein the coupling element is a second coupling element, and wherein the method further comprises: filling the first cavity with a first elastomer material such that the first elastomer material is in contact with the pressure responsive element; and allowing the first elastomer material to cure into a first coupling element.

15. The method of claim 13 wherein filling the second cavity with the elastomer material comprises filling the second cavity with a 2-part silicone gel material.

16. The method of claim 13, further comprising: welding the first well member to the second well member; and coupling the second well member to the measurement component via adhesives.

17. The method of claim 13, further comprising enclosing the first well member, the second well member, and the measurement component inside a housing, wherein disposing the pressure responsive element comprises aligning each of the first well member, the second well member, and the pressure responsive element with an aperture of the housing.

18. A sensor subassembly, comprising: a first w ell member; a second well member aligned with the first well member; a pressure responsive element disposed between the first well member and second well member, wherein the first well member and the pressure responsive element define a first cavity aligned with the aperture, and wherein the second well member and the pressure responsive element define a second cavity; a measurement component positioned in the second cavity; anda coupling element disposed in the second cavity and in contact with each of the pressure responsive element and the measurement component, wherein, when the sensor subassembly is implanted within a patient, the measurement component is configured to measure one or more physiological parameters of the patient conveyed by the pressure responsive element and the coupling element.

19. The sensor subassembly of claim 18 wherein the coupling element is a second coupling element, and wherein the sensor subassembly further comprises a first coupling element disposed in the first cavity and in contact with the pressure responsive element.

20. The sensor subassembly of claim 19 wherein each of the first coupling element and the second coupling element is composed of a silicone gel material.

Images