Covered bioelectronic endoluminal prosthesis and assembly of bioelectronic prostheses, systems and methods

Abstract

A covered intravascular prosthesis comprises an at least partially tubular scaffolding, a membrane excluding a tissue volume, integrated circuit(s), transducer(s), and transmitter(s) to provide monitoring functions to the vascular tissue. The prosthesis can be powered externally, or harvest energy from the body, and monitors and characterizes surrounding tissues, optionally characterizes its own structural integrity, and reports this information to an external system over an encrypted channel.

Description

[0001] COVERED BIOELECTRONIC ENDOLUMINAL PROSTHESIS AND ASSEMBLY OF BIOELECTRONIC PROSTHESES, SYSTEMS AND METHODS

[0002] CROSS-REFERENCE TO RELATED APPLICATION

[0003] This patent application claims priority of U.S. Patent Application No. 63 / 746,888, filed on January 17, 2025, the entire disclosure of which is hereby incorporated by reference herein for all purposes.

[0004] FIELD

[0005] The application generally relates to the field of covered stent and stent grafts for medical applications. More specifically, the present application relates to a covered stent or stent graft with integrated electronics for imaging and measuring various physiological parameters, optionally to prevent restenosis, and optionally to monitor an operational integrity of the stent.

[0006] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0007] This invention was made with Government support under 75N91024C00033 awarded by Advanced Research Projects Agency for Health (ARPA-H). The government has certain rights in the invention.

[0008] BACKGROUND

[0009] Stent grafts and flow diverters are used to exclude tissue within a human body or an animal body from a fluid circulation. The excluded tissue is typically at least an aneurysm, pseudoaneurysm, arteriovenous fistula, dissection or other tear or rupture of a vascular lumen; the fluid circulation is usually the systemic blood circulation; and stent grafts and flow diverters are used in the routine treatment of these and other conditions.

[0010] A stent graft consists of at least one segment of rigid, usually metallic, usually tubular, scaffolding, and one or more membranes. When used to treat an aneurysm, a stent graft can be deployed using minimally-invasive intravascular techniques, wherein the stent graft is maneuvered into place by means of an intravascular catheter system, and expanded at the site of the aneurysm. When expanded, the stent graft forms a passageway within the lumen of the artery, allowing blood to flow from central to peripheral regions, while also decreasing the pressure on the aneurysmal sac walls.Two common indications for stent graft implantation are abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA). Both of these conditions predispose to aortic rupture, a condition which carries an extremely high rate of mortality. When deployed within an aortic aneurysm, a stent graft is typically used to bridge the proximal and distal healthy segments of the vessel with a passageway that allows blood to flow, and to exclude from the systemic circulation a volume of the diseased aorta which is otherwise susceptible to aneurysmal sac expansion and rupture. One proposed and well-studied mechanism of action of stent grafts is depressurization of the aneurysmal sac: the pressure within the passageway is transferred to the membranes, and then to the scaffolding. In this way, the aneurysmal sac walls are spared the mechanical load to which they would otherwise be subject.

[0011] Stent grafts for AAA and TAA are often highly-specialized devices. Some stent grafts for AAA comprise an assembly of several separately-implantable apparatuses, each a stent graft in its own right. This is sometimes necessary because the diseased portion of artery may span several branch arteries. Commercial stent grafts for endovascular aneurysm repair (EVAR) of AAA often have an aortic portion, called the body, and two iliac limbs. A first device, consisting of the body and one limb, attached at fabrication, is inserted through an artery in one leg, usually the right leg. After expanding and bracing the central and peripheral ends of the stent graft against the healthy artery wall (this section of artery wall is called the landing zone), often in the infrarenal aorta centrally and the common or external right iliac artery peripherally, a second limb of the stent graft is inserted through an artery in the contralateral leg, and braced against typically the left iliac artery distally, and a short tubular segment inferior to the bifurcation in the first device centrally. In this way, the aneurysmal sac may be sealed off from the pressure of the aorta. Stent grafts for thoracic endovascular aneurysm repair (TEVAR) of TAA are similarly fabricated and deployed, except insofar as that they have a body and (if applicable) limbs suited to thoracic aortic anatomy. Fenestrations or additional sections may be added, such as for internal iliac, renal, celiac, mesenteric, brachiocephalic, carotid, subclavian or other branch vessels. Physicians may in some cases modify stent grafts to accommodate an individual patient’s anatomy.

[0012] Standard of care surveillance of aortic aneurysm status post endovascular aneurysm repair includes at least annual monitoring with computed tomography (CT) angiography. This surveillance regimen is costly and exposes the patient to high cumulative doses of ionizing radiation, but is justified on the high mortality rate ofaneurysm rupture. Concerning findings include aneurysm expansion, damage to or breakage of the stent graft, migration of the stent graft, and endoleak. Endoleak is defined as the flow of fluid into the aneurysmal sac volume outside of the stent graft, and is classified according to type. Flow of fluid through the seal at the landing zones constitutes a Type I endoleak. Flow of fluid into the aneurysmal sac volume through a branch artery is classified as a Type II endoleak. Flow of fluid through a tear in a membrane, a gap between devices within the assembly or other damage to the apparatus is called a Type III endoleak. Aneurysmal sac expansion without an identifiable endoleak is designated Type V endoleak. Type I and III endoleaks are typically intervened upon because of their implications for sac expansion and predisposition to aneurysmal rupture. In contrast, Type II endoleaks are of unclear significance and may either be associated with sac expansion or not. Contrast-enhanced ultrasound has been advocated as an alternative to CT angiography for follow-up monitoring after EVAR, however, this technique has seen limited adoption, perhaps due to the requirement for trained personnel. A technology that accurately monitors aneurysms and stent grafts for expansion, device damage, device migration and endoleak at decreased cost and with lower radiation exposure would represent a substantial improvement in the state of the art.

[0013] Aneurysmal sac pressure has been proposed as a predictive factor in aneurysm expansion status post E VAR, especially in cases of Type II endoleak of unclear significance. The U.S. Food and Drug Administration (FDA) has approved devices that may be implanted within the aneurysmal sac volume to report local pressure when interrogated by a clinician. The adoption of these devices has been limited by large size (and consequent technical complexity and risk of the implantation procedure), unreliability of pressure measurements (especially when devices are sandwiched between the limbs of a stent graft or between a stent graft and another anatomical structure), interference in telecommunication between the device and the interrogator in a high-noise hospital environment, and the theoretical locality of pressure measurement (due to variations in pressure throughout the aneurysmal sac volume attributable to thrombus). A technology that predicts the risk of aneurysmal sac expansion, the significance of a Type II endoleak, or any other complication of stent graft implantation would represent a substantial improvement in the state of the art.

[0014] Beyond the aorta, stent grafts of various configurations have been used to treat aneurysms, pseudoaneurysms, arteriovenous fistulae, ruptures and dissections throughout the body.Cerebral flow diverters are implantable prostheses similar in function to stent grafts. Cerebral flow diverters are typically used to treat aneurysms within the blood supply of the brain. Flow diverters comprise a scaffolding with a plurality of struts; they do not typically comprise membranes, and the reduction in flow and pressure within the target cerebral aneurysm is subserved by the low porosity of the mesh formed by the struts, which may act as a rectifier, allowing blood to flow out of the aneurysm, but not in. This functionally excludes the aneurysm from the fluid circulation. In-stent stenosis, aneurysmal sac expansion, and device damage are potential complications, monitoring for which typically requires follow-up imaging. Follow-up monitoring, typically with CT or magnetic resonance angiography, is indicated at about 6 and 12 months postoperatively, and at varying intervals thereafter, per the judgement of the surgeon and the specification of the protocol being followed. A technology that accurately monitors aneurysms and flow diverters for aneurysmal sac expansion, device damage (such as changes to the structural integrity of the scaffolding), and in-stent stenosis at decreased cost and with low radiation exposure would represent a substantial improvement in the state of the art.

[0015] Stent grafts are conceptually and structurally related to several popular families of medical devices. Like a stent graft, a covered stent consists of at least a rigid scaffolding and at least one membrane. In this disclosure, we will refer to as stent grafts all apparatuses or assemblies consisting of at least a rigid scaffolding and at least one membrane designed to exclude tissue within a human body or an animal body from a fluid circulation, and we will refer to as covered stents all apparatuses and assemblies consisting of at least a rigid scaffolding (z.e. a stent) and at least one membrane designed for some other purpose. One of the most popular indications for covered stents is the treatment of stenosed or occluded lumens within a human body or an animal body.

[0016] Covered stents are popular in the treatment of peripheral arterial disease of the femoropopliteal and iliac artery segments, with recent data supporting their superiority to bare metal stents in some populations of patients with these conditions. Another example is covered endovascular reconstruction of the aortic bifurcation (CERAB) for severe aortoiliac occlusive disease, for which three covered stents are typically used to reconstruct the aortic bifurcation.

[0017] One frequent complication of vascular interventions using covered stents is instent restenosis. Lifelong surveillance with Doppler ultrasound is typically indicated. Reinterventions for in-stent restenosis may be more durable than re-interventions for occlusion, but most clinically feasible intermittent monitoring regimens cannotrealistically identify all cases of critical restenosis before occlusion. A technology that enables continuous monitoring of covered stent restenosis would represent a substantial improvement in the state of the art. Because of their structural similarity to stent grafts, developments in stent graft technology can potentially improve covered stents, and the treatment of occlusive arterial disease.

[0018] Another medical intervention conceptually linked to EVAR is the implantation, for vascular disease or any other indication for which stents are used, of multiple overlapping stents. This technique allows for greater lengths of lumen to be treated than the length of a single stent. Information about the relative positions of the stents in an assembly of at least two stents is relevant to clinicians during and after the implantation procedure. This includes information about apposition between the stents, which, if present around their full circumference, may prevent unacceptably-high restenosis in any gaps between stents that may otherwise be present, and micromotion between stents that can lead to stent damage and tissue injury. Information about the degree of expansion of the scaffolding comprising each stent in the assembly is also valuable to clinicians. Clinicians currently confirm apposition between stents using invasive technologies like intravascular ultrasound (IVUS) and optical coherence tomography (OCT). A technology that enables collection of spatial data from assemblies of two or more stents in a minimally-invasive and continuous manner would represent a substantial improvement in the state of the art. Because stent grafts for EVAR also rely on circumferential apposition between devices to insure against Type III endoleak, developments in stent graft technology can potentially improve assemblies of multiple overlapping stents, and the treatment of the full range of conditions for which they are used.

[0019] Patients who undergo implantation of stent grafts and covered stents are at risk of myocardial infarction and other medical illness. An apparatus that monitors for myocardial infarction and other medical illness in this population would represent a substantial improvement in the state of the art.

[0020] BRIEF SUMMARY

[0021] The following is intended to be a brief summary of various aspects of the disclosed implementation and is not intended to limit the scope of the invention(s).

[0022] In one aspect, an implantable endoluminal apparatus comprises an at least partially tubular scaffolding expandable in a body lumen such that, in an expanded configuration, at least a portion of the scaffolding is braced against an inner wall of thebody lumen to provide a fluidly communicative passageway through the apparatus. In some implementations, the scaffolding is physically coupled to a flexible membrane that moves with the scaffolding, and excludes from fluid circulation a volume of tissue, such as an aneurysm, pseudoaneurysm, arteriovenous fistula, dissection, tear, rupture, or other anatomical structure of clinical interest. In some implementations, the apparatus further comprises at least one integrated circuit (IC) physically coupled to the scaffolding and communicatively coupled to one or more transducers physically coupled to at least one of the scaffolding, the membrane, such that when implanted the transducers are mechanically coupled to tissue adjacent to the scaffolding. In some implementations, the transducers are mechanically coupled to the excluded tissue volume. In some implementations, the transducers comprise reversible electromechanical transducers, including piezoelectric micromachined ultrasound transducers (PMUTs) or capacitively micromachined ultrasound transducers (CMUTs), to deliver acoustic or ultrasonic pulses or waves and to receive returned signals that carry information about structural or functional characteristics of tissue. In some implementations, signals from the acoustic interface are processed to obtain B-mode and Doppler images, including duplex images, to support clinically relevant assessments such as endoleak detection and endoleak characterization, aneurysmal sac diameter measurement and enlargement monitoring, and detection of migration, damage, and inadequate sealing of the apparatus against the inner wall of the body lumen. In some implementations, the apparatus additionally comprises other transducers, including pressure sensors, electrodes, optical or electromagnetic transducers, or conductors arranged to support characterization of tissue, scaffolding or flexible membrane. The IC is further communicatively coupled to at least one transmitter (and optionally a receiver) to transmit data to an external system, and in some implementations receives power and commands from the external system.

[0023] In another aspect, methods are provided for monitoring and risk stratifying a patient after implantation with the apparatus based on data collected by the apparatus. In some implementations, ultrasound imaging data (including B-mode and Doppler imaging data), pressure data, or additional sensor data are processed in an external system to identify one or more predictor variables associated with adverse clinical outcomes. In some implementations, a classifier or regression model is trained using multidimensional data collected from multiple individuals and corresponding real-world outcomes, and is used to predict risk of adverse clinical outcomes for an implanted patient. For aneurysms, adverse clinical outcomes include aneurysm sac expansion and rupture, and risk outputsmay be used to trigger alerts, increase surveillance intensity, or prompt clinical intervention.

[0024] In another aspect, systems and assemblies are provided comprising multiple overlapping implantable components. In some implementations, both components are apparatuses that include at least one IC and at least one transducer such as an ultrasound transducers, such that the assembly supports real-time information transmission during implantation (including overlap assessment, relative position ascertainment, and apposition confirmation) and continued monitoring over time for endoleaks (including Type III endoleaks at interfaces), migration, dislodgement, and damage. In other implementations, a first component is an apparatus that comprises ultrasound capability and telemetry, and a second component comprises limited or no electronic hardware, such that the first apparatus localizes the second apparatus using acoustic or ultrasonic pulses to confirm placement and to monitor the assembly over time.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 A is a schematic diagram showing an example implementation of an apparatus comprised of a scaffolding, membrane, reversible mechanical transducers, integrated circuits, and other sensors and transducer components.

[0026] FIG. IB is a schematic diagram showing an implementation in which the membrane is a flexible circuit board.

[0027] FIG. IC is a schematic diagram showing an implementation of various methods of physically coupling the at least one integrated circuit with the scaffolding, according to at least one illustrated implementation.

[0028] FIG. 2A is a cross-sectional view of an example apparatus implementation positioned in an aneurysm.

[0029] FIG. 2B is a schematic diagram showing an assembly of two apparatuses, according to at least one illustrated implementation.

[0030] FIG. 2C is a cross-sectional view of an example implementation to assess a relative position of two apparatuses and a Type III endoleak.

[0031] FIG. 3 is a schematic diagram showing an implementation of apparatus with struts replaced by at least one integrated circuit and at least one piezoelectric transducer.

[0032] FIG. 4A is a block diagram showing electronic systems for a preferred

[0033] implementation.FIG. 4B is a block diagram showing an integrated circuit for the preferred implementation.

[0034] FIG. 4C is a schematic diagram showing an interface to receive a signal from a transducer, according to at least one illustrated implementation.

[0035] FIG. 4D is a schematic diagram showing an interface for an acoustic transducer, according to at least one illustrated implementation.

[0036] FIG. 4E is a schematic diagram showing an interface for a piezoelectric transducer that further supports power harvesting, according to at least one illustrated implementation.

[0037] FIG. 5A is a schematic diagram showing a representation of a heart at enddiastole.

[0038] FIG. 5B is a cross-sectional view of a coronary artery at end-diastole showing apparatus placement and flexure.

[0039] FIG. 5C is a schematic diagram showing a representation of a heart at end-systole. FIG. 5D is a cross-sectional view of the coronary artery at end-systole showing apparatus placement and flexure, according to at least one illustrated implementation.

[0040] FIG. 6 is a block diagram of an impedimetric receiver system, according to at least one illustrated implementation.

[0041] FIG. 7 is a cross-sectional view of an example apparatus in a representative complex anatomy, according to at least one illustrated implementation.

[0042] FIG. 8A is a schematic diagram showing an example of the position of an external device to exchange energy and information with the implant, according to at least one illustrated implementation.

[0043] FIG. 8B is an enlarged schematic view of an example implementation of an external system or device to power and communicate with the implant, according to at least one illustrated implementation.

[0044] FIG. 8C is a schematic diagram showing an example representation of a deployment location for an apparatus, according to at least one illustrated implementation.

[0045] FIG. 8D is an enlarged sectional view of an example implementation of an apparatus in a coronary artery, receiving power and exchanging information with an external system.FIG. 9 is a block diagram showing an exemplary implementation of a software algorithm for the operation of apparatus, according to at least one illustrated implementation.

[0046] FIG. 10 a flowchart illustrating exemplary processes for interacting with the implant to receive information from the apparatus and present the information, according to at least one illustrated implementation.

[0047] FIG. 11 A is a flowchart illustrating an alert framework from the apparatus, according to at least one illustrated implementation.

[0048] FIG. 1 IB is a schematic example of a measured time-series parameter with alert thresholds, according to at least one illustrated implementation.

[0049] FIG. 12 is a flowchart of process for detecting and reporting structural damage, according to at least one illustrated implementation.

[0050] FIG. 13 is a flowchart of operation of a nominal implementation of apparatus. FIG. 14A is a schematic diagram showing an example of a risk assessment with inputs from predictor metrics and known outcomes, according to at least one illustrated implementation.

[0051] FIG. 14B is a schematic diagram showing an example of outcome prediction using a classifier based on an individual predictor metric, according to at least one illustrated implementation.

[0052] FIG. 14C is a schematic diagram showing an example of outcome prediction using a regression based on an individual predictor metric, according to at least one illustrated implementation.

[0053] FIG. 15A is a schematic diagram showing an assembly of an apparatus and a stent graft, according to at least one illustrated implementation.

[0054] FIG. 15B is a cross-sectional view of an example implementation to assess the relative position of an apparatus and a stent graft and to assess a Type III endoleak, according to at least one illustrated implementation.

[0055] DETAILED DESCRIPTION

[0056] In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with processor-based systems,computers, processors, memory and other storage media; telecommunications equipment including wired and wireless communication equipment, firewalls, servers, wireless radios (i.e., transmitters, receivers or transceivers); transducers and sensors, and artificial intelligence, machine-learning and / or artificial neural networks have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments. Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.”

[0057] Reference throughout this specification to “one implementation” or “an implementation” or to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the implementation or embodiment is included in at least one implementation or embodiment. Thus, the appearances of the phrases “in one implementation” or “in an implementation” or “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same implementation or embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations or embodiments.

[0058] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0059] As used in this specification and the appended claims, the term module means a set of hardware (i.e., a set of circuitry) and, or, a set of processor-executable instructions or processor-executable logic stored in nontransitory processor-readable media (also known as computer-readable media) as software and / or firmware or as embodied in a set of circuits (Application Specific Integrated Circuit, programmed Field Programmable Gate Array), and can include or be implemented in artificial intelligence systems, machine-learning systems, machine-learning models, and, or, trained artificial neural networks (e.g., autoencoders, variational autoencoders).

[0060] As used herein and in the claims, the term tissue and various thereof (e.g., tissues) mean bodily tissue including anatomical bodily tissue (e.g., vasculature, organs, muscle, tendon, ligament, bone, skin, cartilage) and bodily fluids (e.g., blood) unless expressly limited to one or the other type of bodily tissues.The headings and Abstract of the Disclosure provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.

[0061] The apparatus described in this disclosure is comprised of a metallic, polymeric, resorbable, or hybrid scaffolding that is expandable into a body lumen, such that when expanded it is at least in part braced against an inner wall of a body lumen. The scaffolding is comprised of at least one strut and includes at least a tubular portion, such that a fluidly communicative passageway through the scaffolding is formed when the scaffolding is expanded within a body lumen and at least in part braced against the inside wall of the body lumen. The scaffolding may be comprised in part or entirely of, for example, a bare metal stent, drug eluting stent, peripheral bare metal stent, bioresorbable stent, inferior vena cava filter, or flow diverter. The scaffolding may also be comprised in part or entirely of the rigid member or members of a stent graft or a covered stent, though other common endoluminal structures may comprise the majority of or all of the scaffolding. The scaffolding may be braced in one of a thoracic aorta, an abdominal aorta, an (internal, external or common) iliac artery, a femoral artery, a popliteal artery, a (anterior or posterior) tibial artery, a fibular artery, a subclavian artery, an axillary artery, a brachial artery, a renal artery, a celiac trunk, a (superior or inferior) mesenteric artery, a mesenteric vasculature, a coronary vasculature, a cerebral vasculature, a pulmonary vasculature or a peripheral vasculature, any great vessel, a carotid artery, a gastrointestinal tract, an esophagus, a colon or a rectum, a biliary pancreatic duct or a pancreas, a urethra or a ureter or any body lumen inside the human or animal body.

[0062] The scaffolding is physically coupled to at least one transducer, such that the transducer is mechanically coupled to a tissue of the body, or a fluid of the body adjacent to the expandable scaffolding. In some implementations the transducer is an electromechanical transducer, such as an acoustic transducer, a piezoelectric micromachined ultrasound transducer (PMUT), a piezoelectric material, a cavity pressure sensor, a capacitively micromachined ultrasound transducer (CMUT), or the like. Some implementations utilize electromechanical transducers that are reversible. A reversible electromechanical transducer converts electrical or electromagnetic energy into mechanical energy and converts mechanical energy into electrical or electromagnetic energy. Examples of reversible electromechanical transducers familiar to those knowledgeable in the art include PMUTs and CMUTs.

[0063] In further implementations, at least one transducer is an electrode, comprised of at least one of gold, silver / silver chloride, tantalum, titanium nitride, iridium oxide,platinum, glassy carbon, PEDOT:PSS, or other metallics, alloys, dielectrics, or conductive polymers. In some implementations, the electrodes may be used to measure a biological potential differential across the length of the body lumen traversed by the scaffolding. In some implementations, the at least one electrode may be used to deliver a therapeutic electrical current to the tissue. In some implementations the at least one electrode is used to characterize the impedance of at least one of the body lumen, the tissue adjacent to the scaffolding at at least one frequency.

[0064] In some implementations, the one or more transducer is a chemical sensor that measures the concentration of circulating proteins or biomolecules in the fluidly communicative passage that may be biomarkers for pathological conditions, or whose levels may be of clinical interest. These chemical sensors may comprise a metallic material, such as gold, platinum, or carbon-based substrate, with conjugated aptamers bonded to the surface, either directly or through a linkage molecule. The at least one chemical sensor is communicatively coupled to the integrated circuit, which further comprises a potentiostat, such that a signal can be generated from the interface through cyclic voltametric sweeps, those cyclic voltammetry sweeps ultimately containing information about the tissue or fluid in the body. The aptamers bound to the surface of the chemical sensor may be sensitive to at least one of troponin (T or I), creatine kinase MB, myoglobin and glucose, serotonin, cytokines, inflammatory biomarkers, cortisol, or any other biomarker of clinical interest. The optical signal received by electro-optical transducers may also be used to infer concentrations of one or more compounds within the body through spectroscopy.

[0065] In some implementations, the one or more transducers are at least one of a lightemitting diode, Vertical Cavity Surface-Emitting Laser (VCSEL), photodiode, singlephoton-avalanche diode (SPAD), or other electro-optical transducer. The one or more integrated circuits physically coupled to the scaffolding is further comprised of a driver to energize an optical emission (e.g. light-emitting diode). In further implementations, the at least one interface is communicatively coupled to one or more of these electro-optical transducers. These elements may be operable in the visible, infrared or ultraviolet range. They may be used to evaluate vascular health (for example, monitoring of atheromatous plaques with near infrared spectroscopy, or monitoring aneurysmal sac health), or radiate light into the vessel wall (i.e. photobiomodulation). Optical transducers may line the abluminal and adluminal aspects of the scaffolding, depending on if the implementation isdesigned to treat in-stent restenosis (adluminal) or existing plaques or aneurysmal sac pathology (abluminal).

[0066] In some implementations, the at least one transducer is at least one a cavity pressure sensor, capacitive pressure sensor, MEMS pressure sensor, or the like. The pressure sensor is commonly comprised of two conductive thin films separated by a compressible dielectric or a compressible cavity. Environmental pressure modulates the capacitance of this sensor in a reproducible fashion. The pressure sensor is communicatively coupled to the integrated circuit, which receives a signal from the interface containing information about the localized pressure adjacent to the pressure sensor. In some implementations, the IC autonomously takes periodic measurements from the at least one pressure sensor. In some implementations, the measurement is taken on-demand by receiving a command from the system outside of the body communicatively coupled to the integrated circuit. This information can be aggregated and stored on a memory at least one of inside the integrated circuit or in a second integrated circuit, and transmitted by the transmitter to the external system outside of the body. In some implementations, at least one of the at least one pressure sensor is comprised of a PMUT.

[0067] The at least one transducer may be positioned on any combination of the adluminal, abluminal, or side aspect of the scaffolding. The scaffolding can have a surface normal and can include or carry at least one component that is tangent to a tubular portion of the scaffolding.

[0068] The scaffolding is also physically coupled to at least one integrated circuit (IC) chip, that is communicatively coupled to the at least one transducer. In some implementations, the IC is structurally thinned. In further implementations the IC is structurally thinned to the point of mechanical flexibility. The IC is operable to at least one of process, store, or communicate the information about a tissue of the body. In some implementations, this information includes information about the patency of the body lumen. The at least one IC may be positioned on the adluminal aspect of the scaffolding or the abluminal aspect of the scaffolding.

[0069] Some implementations comprise at least one flexible membrane physically coupled to the scaffolding. This flexible membrane moves with the scaffolding when the scaffolding is expanded within the body lumen, and acts to functionally decrease the porosity of the scaffolding. In some implementations, this flexible membrane is part of a stent graft, such as an endograft for EVAR, and the flexible membrane further excludes from fluid circulation a volume of tissue, such as an aneurysm. Flexible membranes maybe used to facilitate the exclusion from circulation of at least one aneurysm, pseudoaneurysm, arteriovenous fistula, vascular dissection or other anatomical structure of clinical interest. The at least one transducer and the at least one IC may (in addition to being physically coupled to the scaffolding) be physically coupled to the abluminal aspect of the flexible membrane or the adluminal aspect of the flexible membrane.

[0070] FIG. 1A shows an example implementation of the apparatus with a flexible membrane, and wherein ICs (102) are physically coupled to the abluminal aspect of the scaffolding (101) and the adluminal aspect of the scaffolding (114). Both the abluminal aspect of the membrane (110) and the adluminal aspect of the membrane (116) are shown. The scaffolding shown is tubular. The scaffolding and the membranes collectively comprise a stent graft. The adluminal aspect of the scaffolding (101) faces the fluidly communicative passageway, denoted by 111, when the scaffolding is expanded within a body lumen. ICs, transducers, transmitters, and other components may also be attached to the side aspect (115) (aka side surface) in some implementations. The transducers in this implementation are physically coupled to the ICs, but they may optionally be physically coupled to the scaffolding directly, the flexible membrane directly, or to any other component that is physically coupled to the scaffolding. The transducers illustrated in this implementation are: a pair of electrodes (122) on the abluminal aspect of the scaffolding (101), reversible electromechanical transducers (106) on the abluminal aspect of the scaffolding (101) and the adluminal aspect of the scaffolding (114), a one pressure sensor (113) on each of the abluminal aspect of the scaffolding (101) and the adluminal aspect of the scaffolding (114), a photodetector (107), and a light-emitting diode (108), a chemical sensor (109). The placement of reversible electromechanical transducers on the abluminal aspect of the scaffolding (101) may be particularly advantageous to assess the condition of the aneurysm, pseudoaneurysm, arteriovenous fistula, vascular dissection or other anatomical structure being excluded from fluid circulation, and to monitor for aneurysmal sac expansion and endoleaks. Pressure sensors on the abluminal aspect of the scaffolding and the adluminal aspect of the scaffolding facilitate the calculation of a Mean Pressure Index (MPI), the utility of which has been studied in the prediction of aneurysmal sac expansion. In other implementations, the pressure sensors may be at opposite ends of the tubular portion of the scaffolding so as to detect the pressure drop across the scaffolding and to facilitate the calculation of the fractional flow reserve (FFR).

[0071] The IC is communicatively coupled to at least one transmitter, which is physically coupled to the scaffolding. The at least one transmitter is operable to transmit informationfrom the apparatus when it is implanted in the body lumen of the body. In some implementations, the transmitter is a part of the integrated circuit. In some implementations, an acoustic transducer, electromagnetic radiator, strut of the scaffolding, coil, antenna, or antenna system are communicatively coupled to the at least one transmitter. Consequently, the transmitter may transmit information about the tissue or the apparatus in the form of electromagnetic or mechanical pulses or waves.

[0072] In some implementations, the IC may be communicatively coupled, via the transmitter, to an external device or external system, outside of the body. In some implementations, the IC may be communicatively coupled, via the transmitter, to another device implanted within the body, but external to the apparatus. The communication link between the apparatus and the external system may occur over an instrumentation scientific medical (ISM) band, 13.56 MHz, 433 MHz, 866 MHz, 915 MHz, medical instrumentation communication service band, 402-405MHz, an IEEE communication standard band, an IEEE 802.15.1 protocol, an IEEE 802.15.4 protocol, or an IEEE 802.11 protocol, ultrawideband link, or any communication protocol or adhering to any standard. In some implementations, the integrated circuit further comprises a cryptographic element, which makes the integrated circuit operable to further process the data by at least one of encrypting, encoding, processing, decrypting, decoding, hashing, obfuscating, or otherwise generating derived information or metadata to be sent. The transmitter may transmit data, metadata, or a value derived from data collected from the at least one transducer, information about a state of the apparatus or software running on the at least one integrated circuit, information about the interaction between the apparatus and another apparatus or an endoluminal prosthetic apparatus, or a notification, by the transmitter of the apparatus to an external device at such time that an amount of collected data, a value derived from the data or an integrity of the apparatus takes certain defined values, or at a defined time or defined set of times that is specified by a manufacturer, a clinician, a patient, or a third party. In some implementations, the transmitter may be operable to respond to at least one of: receipt of a query from the external system; or a wireless technology activated by an electronic medical record software.

[0073] In some implementations, the IC is further communicatively coupled to at least one of a conductive coil, inductor, antenna, electromagnetic receiver, or at least one strut of the scaffolding, to receive energy from an external system or device in the form of electromagnetic radiation incident on the apparatus. In a further implementation, the scaffolding is physically coupled to at least one PMUT, which converts a time-changingpressure into electrical charge based on the piezoelectric effect, so that the apparatus may receive power in the form of mechanical, ultrasonic or acoustic energy from an external system or device. This allows the implant to be energized by ultrasonic signal originating from outside of the apparatus. The transducers may be affixed to the scaffolding, patterned into the scaffolding, and electrically coupled to the IC via a polymeric interconnect board designed to route conductors from one or more integrated circuits to the one or more PMUT. The at least one PMUT can be used to harvest energy from the motion of organs or tissues while implanted in the body lumen. The at least one PMUT may generate a charge in response to a stimulus applied to the at least one PMUT, from a body or fluid movement, including at least one of articular motion, pulsatile motion, or skeletal motion. In implementations receiving power from an external device or system, at least one of the ICs further comprises a power receiver, power recoverer, or power converter, operable to supply power to the IC and other components. Any of the power receiver, power recoverer, or power converter may also be a transmitter or receiver of information about the tissue of the body, about the apparatus, about another apparatus, or about the interaction between the apparatus and at least one other apparatus using its respective modality: electromagnetic or mechanical.

[0074] The transmitter in the implementation shown in FIG. 1A is on or in the IC (112), is an electromagnetic radiator, and makes contact with the abluminal aspect of the scaffolding (101), the scaffolding functioning as an antenna, and improving the effectiveness of the transmitter in transmitting information about the tissue or the apparatus, another apparatus or the interaction between apparatuses to the external device in the form of an electromagnetic signal. Moreover, in this implementation, the transmitter also functions as a receiver of information from the external device, the scaffolding functioning as an antenna to improve the effectiveness of the receiver.

[0075] Receiving, by the receiver, can be used to upload now alert criteria, software updates, firmware, or effector commands to the apparatus. It can also be used to enter modes in which data are collected and transmitted in real-time.

[0076] In some implementations, the at least one flexible membrane may also be comprised, in all or part, of at least one flexible circuit board, electromagnetic radiator, electrode or passivated patterned circuit. FIG. IB shows one implementation in which the flexible membrane consists of a flexible circuit board, the adluminal aspect of which is denoted 118, and the abluminal aspect of the flexible membrane is denoted 117. In this implementation, the flexible circuit board is wrapped around the scaffolding, theadluminal aspect of the scaffolding labeled 114, the abluminal aspect of the scaffolding labeled 101, and the side aspect of the scaffolding labeled 115. In various implementations, the flexible circuit board, passivated patterned circuit or other functional component may be wrapped fully or partly around all or part of the scaffolding. Reversible electromechanical transducers (106) are mounted on the adluminal aspect of the flexible membrane (118), facilitating assessment of the fluidly communicative passageway (111). Reversible electromechanical transducers (106) are also mounted on the abluminal aspect of the flexible membrane (117), which may be more advantageous for imaging the excluded tissue volume, comprising structures such as an aneurysm, pseudoaneurysm, vascular dissection, arteriovenous fistula, and the like.

[0077] FIG. 1C shows an implementation with an IC and transducers physically coupled to the scaffolding or the flexible membrane using a variety of methods. The abluminal aspect of the scaffolding (101), the adluminal aspect of the scaffolding (114), the side aspect (115)of the scaffolding (114), abluminal aspect of the membrane (110), and the adluminal aspect of the membrane (116) are shown. Several ICs (119) are physically coupled to the abluminal aspect of the scaffolding (101) and the adluminal aspect of the scaffolding (114), adjacent to the fluidly communicative passageway (111), using a snap fit. Another IC (120) is physically coupled to the membrane using a flexible tie (121). Each of these ICs is physically coupled to at least one bidirectional mechanical transducer (106). Physically coupling an IC or a transducer to the scaffolding using a snap fit, interference fit, casing, weld (through welding), glue (through gluing), sputter coat, adhesive, or encasing the IC within a rigid packaging, holds the relative position and orientation of the IC or transducer constant, which is advantageous, for example, when performing imaging on an aneurysm. Physically coupling the IC or transducer with a tie may be more appropriate when position and orientation are less important, such as when measuring pressure within the aneurysmal sac, which can likewise be performed bidirectional mechanical transducers as well as pressure sensors. However, all methods of physically coupling the ICs or transducers may be used for the full range of applications described in this disclosure. Methods involving a tie wherein the transducers are used for imaging may, however, require a software compensation for relative motion that is familiar to those knowledgeable in the art.

[0078] FIG. 2A shows an implementation of the apparatus implanted within an aneurysm (202) in cross-section. The stent graft comprises a scaffolding (203) and a flexible membrane (204) that bridge the aneurysm (202), and exclude the aneurysmal sac (233)from a fluid circulation that includes the fluidly communicative passageway (234) formed when the scaffolding (203) is expanded. ICs coupled to the abluminal aspect of the scaffolding (205) that face a section of healthy vessel (201), ICs coupled to the adluminal aspect, aka adluminal surface, of the scaffolding (206) that face the fluidly communicative passageway (234), and ICs coupled to the abluminal aspect of the scaffolding (203) that face the aneurysmal sac (233) are physically coupled to reversible electromechanical transducers (208). Blood entering the aneurysmal sac (233) through a branch artery (209) results in a Type II endoleak (210). A mechanical wave (211) is generated by the reversible electromechanical transducers (208) physically and electrically coupled to the IC (207) facing the Type II endoleak, and propagates toward the Type II endoleak (210). The mechanical wave (211) interacts with the Type II endoleak (210), reflecting and passing through the fluid comprising the Type II endoleak. In this implementation, a returned mechanical wave (212) is reflected back toward the reversible electromechanical transducers (208), carrying information about the Type II endoleak (210) in its latency and intensity. For example, Doppler imaging techniques, familiar to those knowledgeable in the art, can be used to assess the velocity of the fluid comprising the Type II endoleak, however, other parameters, such as size and morphology of the Type II endoleak, as well as structural and functional information about other healthy and diseased tissues can likewise be assessed. The mechanical wave may be an acoustic or ultrasonic pulse, wave or other perturbation of arbitrary form, as best to facilitate the type of imaging being performed, and in a manner familiar to those knowledgeable in the art. In some implementations, the returned mechanical wave (217) may be directed toward a set of electromechanical transducers different from those the mechanical wave resulting in the returned mechanical wave (216) after interacting with the tissue (by means of reflection, refraction or otherwise passing through a tissue or another apparatus). In some implementations the tissue is stationary. A shear wave or compressive force may be used to further characterize the elasticity or viscoelasticity of the tissue through shear wave imaging / elastography. For example, a shear wave (213) is introduced into the tissue by the reversible mechanical transducers (208). A mechanical wave is then emitted by the same or a different set of reversible mechanical transducers (214), and a mechanical wave returned from the tissue interacting with the shear wave (215) carries information about the tissue, in this case a section of healthy vessel (201), e.g., artery, but other healthy and diseased tissue may be likewise assessed, back toward the reversible electromechanical transducers (208). In other implementations, different(overlapping or non-overlapping) combinations of transducers may generate the shear wave or compressive force (e.g., deforming), generate the mechanical pulse or wave, and measure the returned mechanical pulse or wave. In various implementations, shear wave imaging / elastography is also implemented by means of measuring: a shear wave speed, a real and a complex shear modulus, an elastic modulus, a bulk modulus, a viscosity, a relaxation time, a shear wave attenuation, a strain resulting from a mechanical pulse or wave introduced into the tissue volume at least partially excluded from the fluid circulation, or a stiffness. In so doing, information about the excluded tissue volume (in this implementation, the aneurysm and surrounding healthy artery), and information about the tissue within the fluidly communicative passageway can be collected for processing and transmission.

[0079] The apparatus described in this Disclosure comprises at least a tubular portion of scaffolding, which may be expanded in a body lumen partially overlapping the tubular portion of scaffolding of another apparatus, forming a system of two or more apparatuses. A system of two or more apparatuses may offer advantages in collecting information about the interaction between the apparatuses. It may also be advantageous in collecting information about Type III endoleaks that are liable to occur if the apposition between the tubular portion of the scaffolding of each apparatus is inadequate in cases where the system is used to exclude a tissue volume from fluid circulation.

[0080] FIG. 2B shows an implementation of a system comprising an assembly of two apparatuses. A length of an outer apparatus (219) partially overlaps a length of an inner apparatus (218), the outer apparatus and the inner apparatus functioning as stent grafts or covered stents. A Type III endoleak is illustrated (231), fluid escaping into the excluded tissue volume (235).

[0081] FIG. 2C is a section view of the lengths of the apparatuses illustrated in FIG. 2B.

[0082] The Type III endoleak (231) is depicted as the arrow between the overlapping inner apparatus (218) and outer apparatus (219), indicating the flow of fluid into the excluded tissue volume (235), originally from a fluidly communicative passageway (236) formed through the shared lumen of the two apparatuses when they are expanded within the body lumen. A transducer (220) physically coupled to the inner apparatus (218) generates a mechanical or electromagnetic wave (222). The mechanical or electromagnetic wave (222) travels toward a transducer physically coupled to the outer apparatus (221). The mechanical or electromagnetic wave carries information about the relative position of the transducer carried by the inner apparatus (218) and the transducer carried by the outerapparatus (221). A different transducer (224) physically coupled to the outer apparatus (219) generates a mechanical or electromagnetic wave (225), which is directed toward a transducer (223) physically coupled to the inner apparatus (218). The mechanical or electromagnetic wave carries information about the relative position of the transducer (223) carried by the inner apparatus (218) and the transducer (224) carried by the outer apparatus (219). This information is transmitted to an IC (226) physically connected to the inner apparatus (218) by a transmission line (228). The IC (226) also energizes the transducer on the inner apparatus (218) that generates the mechanical or electromagnetic wave (222) via the transmission line (228). The information about the relative position of the transducer (224) physically coupled to the outer apparatus (219) and the transducer (223) physically coupled to the inner apparatus (218) is transmitted to an external device, external to the system, by a transmitter (227) that is communicatively coupled to the IC (226) by the transmission line (228). The transducer physically coupled to the inner apparatus (218) may also collect information about the Type III endoleak (231) by sending a mechanical wave (232) toward the fluid comprising the Type III endoleak (231) and, in combination with the IC (226) to which it is communicatively coupled, measuring the Doppler shift of a mechanical wave returned from the fluid comprising the Type III endoleak (231). The mechanical wave may be an acoustic or ultrasonic pulse, wave or other perturbation of arbitrary form. In some implementations, at least two electrodes may be used as transducers, and the potential detected by the IC at the electrodes carries information about the relative positions of the electrodes. Relative positions of at least two pairs of transducers may be algorithmically combined by techniques familiar to those knowledgeable in the art to infer the relative positions and configurations of the two apparatuses in multiple spatial dimensions. The information about the relative positions of the apparatuses can then be displayed to a patient, clinician or third party in real time, or after a delay. The information may include information about contact or apposition between the apparatuses, but, in this implementation, this information about contact or apposition is derived from the information about relative positions of the apparatuses. Each apparatus depicted comprises a tubular scaffolding, the scaffolding for the outer apparatus visible in cross-section (229). In this implementation, the outer apparatus also comprises a flexible membrane (230), to support the outer apparatus’s function in the role of a stent graft or covered stent. Some implementations do not comprise a flexible membrane and can be used as cerebral flow diverters, conventional bare-metal and drugeluting stents, and fully- and partly-resorbable scaffolds.In some implementations, the electrical coupling between the IC, transducers, and transmitters may be facilitated through the usage of conductive wiring, or a conductive metal patterned on a flexible polymer that can be wrapped around the scaffolding or flexible membranes, or be patterned or deposited onto the scaffolding or flexible membranes, or be incorporated into the scaffolding or flexible membranes. In a further implementation, an electrically-conductive circuit is embedded within or attached upon the scaffolding or flexible membranes in a helical manner and which forms an inductor, one or more capacitors are electrically coupled to the scaffolding, the flexible membranes or any electrically conductive circuit attached upon or embedded within the scaffolding or flexible membranes, and one or more digital switches with inputs from the at least one integrated circuit are placed in series with the inductor and the one or more capacitors, forming an electromagnetic radiator as well as a transmission line through which a mechanical, structural, or functional integrity of the scaffolding or flexible membranes can be assessed.

[0083] In some implementations, the mechanical integrity of the scaffolding is assessed through electrical coupling with at least one of the at least one strut that comprises the scaffolding or at least one of the at least one flexible membrane, forming a portion of at least one transmission line that can be electrically characterized to assess the mechanical integrity of the apparatus. In some implementations, a thin flexible interconnect with a patterned conductor designed to follow the mechanical construction of at least one part of the scaffolding or flexible membrane comprises one or more transmission lines. During scaffolding mechanical breakage, the interconnect is disrupted, which can be measured by the IC electrically coupled to the transmission line, by characterizing the electrical response of the transmission line. Elements of functional integrity, e.g.: biological growths on the apparatus, the mechanical conformation of the scaffolding (e.g. the degree of expansion of its tubular portion), and the proximity of the apparatus to the inner wall of the body lumen or to another apparatus, may be assessed through the deconvolution of an equivalent circuit model determined by characterizing the transmission line electrical response. For example, the inductance of a transmission line that wraps helically around a scaffolding, holding the number of windings constant, is expected to increase when the scaffolding is expanded, resulting in a change that can be measured by the IC. In a further example, a conductive fluid in a lumen functions as a capacitor to ground, changing the impedance of an insulated transmission line within a flexible membrane in a mannerdependent on the exposure of the flexible membrane to the fluid relative to the exposure of the initial flexible membrane to another flexible membrane.

[0084] FIG. 3 shows an implementation of the apparatus comprising a scaffolding (301) that is tubular, the flexible membrane (309) between the struts (305) of the scaffolding. Two of the struts are replaced by ICs (307), the ICs comprising load-bearing members of the scaffolding. In some implementations, a strut can be removed from a fully fabricated scaffold and replaced by an IC. Alternatively, in an additive manufacturing process, as the scaffolding is formed, the regions to be comprised of the IC are not deposited, and instead a connecting interface to the rest of the scaffolding is created to which an IC can be affixed. The IC (307) is physically coupled to the rest of the scaffolding using an interfacial material, (303), such as a biocompatible epoxy with similar mechanical and structural properties as the rest of the scaffolding. In various implementations, transducers, transmitters and other functional components can be likewise incorporated as all or part of a strut of the scaffolding. In this implementation, a PMUT (308) also replaces one strut on each side of one of the ICs (307), and is likewise affixed using interfacial material (303). Replacing load-bearing members of the scaffolding with PMUTs has the potential advantage, in some implementations, that bending along the longitudinal axis of the tubular portion of the scaffolding actuates the PMUTs and has generates energy to partly or wholly energize the IC. Each PMUT (308) is electrically coupled to the IC (307) to which the PMUT is closest with a transmission line (304). Damage to the scaffolding would alter the electrical properties of the transmission line (304) in a manner that can be interrogated by the IC (307) and ultimately transmitted to an external system. Another transmission line (310) runs on one of the flexible membranes (309), and is communicatively coupled to one of the ICs (307). Damage to the flexible membrane would alter the electrical properties of the transmission line (310) in a manner that can be interrogated by the IC (307) and ultimately transmitted to an external system.

[0085] In some implementations, the IC further comprises a driver for an at least one piezoelectric transducer, creating a mechanical pulse or wave from the piezoelectric transducer directed into at least one tissue or toward another mechanical transducer when the integrated circuit is energized to drive the at least one piezoelectric transducer. In some implementations this mechanical pulse or wave is an acoustic or ultrasonic pulse or wave, and interacts with tissue near the scaffolding, with the scaffolding itself, with any flexible membranes that are part of the apparatus, and with the assembly of apparatusescomprising the scaffolding, and returns pulse-echo responses at regions of mechanical impedance mismatch, conveying information about structural changes in the tissue of the body as the wave propagates through the tissue. The one or more transducers convert the returned mechanical pulse or wave into an electrical signal, and this information is communicated to and, processed, digitized, and stored by the IC via an interface. This information may be used to procedurally construct an image of the structure or a graphical representation of the function of the at least one tissue of the human body or the animal body from the converted signal according to A mode, B mode, M mode, Doppler, or duplex ultrasonography, compressive sensing, harmonic imaging, echocardiography, or another imaging procedure familiar to those knowledgeable in the art. This information may provide characterization of the scaffolding itself, including the structural integrity, functional integrity, mechanical continuity, and configuration (such as the degree of expansion) of the scaffolding, the interaction between the scaffolding and the inner wall of the body lumen of the body against which the scaffolding is braced, the structural and functional integrity of any flexible membranes present in the implementation, and the interaction of the scaffolding with the scaffolding and flexible membranes of other apparatuses in the assembly to which it belongs. This information may be used to infer a structural or functional patency of the vessel lumen, a size or shape of an aneurysm (e.g.: aneurysmal sac volume, aneurysmal sac cross-sectional area, aneurysmal sac diameter), a presence of or flow rate through an endoleak, or a flow through a tear in the body lumen, or arteriovenous fistula. This information may serve as a means of calculating fluid flow with the Doppler effect. This information may be enriched with respect to statistical noise through the use of mathematical techniques familiar to those knowledgeable in the art. In some implementations, a numerical transformation is computed by at least one of the integrated circuit or the external system, based on the pulse-echo-response information from the tissue adjacent to the scaffolding to account for a distortion to the received signal resulting from the at least one tissue that could affect the representational accuracy of the information. This numerical transform may be subsequently applied by at least one of the integrated circuit, or an external system, to compensate for the distortion.

[0086] FIG. 4A is a block diagram for the electronic systems for the preferred implementations. The IC (401) is communicatively coupled to at least one transducer (402, 403), and is further communicatively coupled to at least one transmitter (404). In some implementations, an electromagnetic receiver, antenna, coil, inductor, or conductivecomponent of the scaffolding for receiving wireless power from an external system (405) is further communicatively coupled to the at least one integrated circuit.

[0087] FIG. 4B denotes a block diagram for the IC (401). Energy transmitted by the external system to the implanted apparatus is received by least one of an electromagnetic radiator or electromagnetic receiver, antenna, coil, inductor, conductive component of the scaffolding, mechanical transducer, or other transducer, that is electrically coupled to the integrated circuit and converted into a useable supply voltage by a power recoverer circuit (406), allowing for energizing of the integrated circuit (401). In some implementations, the modulation of this delivered power signal may comprise the transmission of data from the external system to the implant. In some implementations, the energy recovered by the power recoverer circuit (406) generates one or more DC supply voltages, from which one or more of biases or references (412) are developed by means of one or more circuit familiar to those knowledgeable in the art. The IC is further comprised of at least one interface (411) to the one or more transducers (402, 403). The interface uses the biases and references to condition the signals received from the one or more transducers (402, 403). In this implementation, the specifications of the interfaces (411) vary according to the type of transducer with which they are paired, however all interact with the control system (408) that is responsible for properly tuning the transducer interfaces, implementing software algorithms, scheduling events, ensuring stable voltage sources and references, handling commands from the external system, and packaging data to transmit via the transmitter via the transmitter controller (410). In some implementations, the at least one transmitter controller (410) is comprised of a tx / rx switch, making the IC operable to both transmit information to and receive information from the external system or device. In such implementations, the IC can both transmit and receive information, and the IC implements a transmitter driver for data transmit and a baseband amplifier for data reception. The transmitter controller is further comprised of an oscillator frequency source (413), which generates the RF carrier frequency that is modulated for wireless communication. In some implementations, this is the MICS band, 402-405 MHz, though other electromagnetic wave frequencies may also be used. The control system is operable to directly send, via the at least one transmitter controller (410), information about the body contained within the signal from the at least one transducer (402, 403) in real time to the external system or device, and to send information stored in a memory (409), to the external system or device. The control system is operable to drive the at least one transducer (402, 403), via the interface (411), which, in this implementation, alsofunctions as a driver, to deliver an effector function at the command of the external system or device, or should a condition requiring effector activation otherwise be reached. The control system (408) may be operable to implement a software algorithm, classifier, statistical inference algorithm, or the like. The control system (408) further monitors and compares information received from the transducers (402, 403) against a statistically derived threshold or predefined constant threshold. When the external system is removed, the control system (408) places the integrated circuit (401) into an ultra-low-power state, and the ultra-low-power timer circuit (407) is activated to count a discrete periodic interval during which power is harvested by the at least one transducers (402, 403). When the timer circuit (407) reaches a predefined value, the control system (408) checks to ensure the power supplies, and biases or references (412) are stable. If these systems are not stabilized, the controller puts the integrated circuit (401) back into its low-power state mode, for a shorter time period, and this process repeats until the power supplies are stable. Then the control system (408) takes a series of measurements about the tissue through the reception of signals from the at least one transducer, via the at least one interface (411), and stores this information in the memory (409). In some implementations, where at least two mechanical pulses or waves containing structural or functional information about tissue are received and converted into signals, the information can be linearly or nonlinearly combined to achieve higher spatial image resolution, greater image signal -to-noise ratio, the combination of components of an image obtained through generation of each of the at least two pulses or waves by a varying subset of the at least one reversible electromechanical transducer, or combination of components of an image obtained by converting each of the at least two mechanical pulses or waves into a signal by a varying subset of the at least one reversible electromechanical transducer. The control system (408) transmits this information to the external system the next time that the external system is brought in communicative contact with the apparatus.

[0088] FIG. 4C denotes the interface (414) for receiving a signal from a transducer (415) that converts a mechanical, electrochemical, or electrical energy into a signal, such as from an electrode transducer or a capacitive pressure sensor. The interface is comprised of a low-noise amplifier (416) with a feedback circuit (417), which may be comprised of at least one passive circuit component, active circuit component, or switch. In some implementations, the low-noise amplifier amplifies a voltage signal in a way that minimally contributes electronic noise to the output, or converts a current signal into avoltage signal in a way that minimally contributes to the electrical noise of the output. Those knowledgeable in the art will be familiar with circuit topologies suitable to provide this amplification. The interface then includes transducer-specific filtering and further gain (418), leading to anti-alias filtering and to an analog to digital converter (419). The analog to digital converter enables the circuit to convert electrical perturbations into digital information that can be processed, stored, or transmitted.

[0089] FIG. 4D denotes the interface (420) for an acoustic or ultrasonic transducer (427), a type of reversible electromechanical transducer. The acoustic or ultrasonic transducer (427) interface (420) has a switch (425), which allows the control system (408) to select between a driven mode (TX) and a receive mode (RX). In the driven mode, the control system generates and delivers a signal or pulse or wave (421), which is amplified by amplifier (422) and driver (423) to achieve a strong-enough pulse (424) to drive the acoustic or ultrasonic transducer (427) to generate a mechanical pulse or wave directed into the tissue or toward another apparatus or transducer. The control system switches the interface into a receive mode, by way of a control signal (426), such that the interface (414) can be responsive to variations in a signal generated by the transducer in response to a mechanical pulse or wave. This signal is conditioned and digitized, as described in FIG. 4C

[0090] FIG. 4E illustrates an example interface (428) for a piezoelectric transducer (430), a type of acoustic or ultrasonic transducer, and by extension, a type of reversible electromechanical transducer. The interface (428) for the piezoelectric transducer (430) is similar to the interface for the acoustic transducer shown in FIG. 4D. The control system (408) generates a signal or pulse or wave (421) that is amplified by an amplifier (422) and a driver (423) to a pulse strong enough to drive the piezoelectric transducer (430) through the switch (429) to generate a mechanical pulse or wave when the control system has configured the switch (429) to the driven mode, using control signals (432). After driving the piezoelectric transducer, the interface may also receive a signal generated by the piezoelectric transducer (430) when exposed to a returned or received mechanical pulse or wave. The control system configures the switch (429) to a receive mode through the control signals (432), which communicatively couples the interface (414), aka reception system, to the transducer (430). The architecture of the reception system is shown in FIG.

[0091] 4C (414). When not driving or receiving a signal from the piezoelectric transducer (430), the control system (408) communicatively couples the piezoelectric transducer (430) to a rectifier circuit (431) through the switch (429), via the control signals (432). The rectifiercircuit (431) takes the signal received from converting the mechanical pulsatility or body movement of a fluid or tissue of the body as an input, and converts that generated charge into a usable direct-current voltage source (433). This allows the integrated circuit (401) to harvest energy from the body, while still supporting acoustic imaging, as well as driving acoustic energy into the scaffolding itself. The rectifier circuit (431) may be an active rectifier, passive rectifier, voltage doubler, or any suitable circuit topology for converting a periodic or aperiodic oscillation and producing a direct-current voltage. Those knowledgeable in the art will be familiar with a variety of potential applicable topologies.

[0092] In some implementations, the IC may be further comprised of at least one of: a power-on reset (POR) circuit to place the digital control systems into a known initial state, a low-drop-out (LDO) voltage regulator to provide a stable and regulated supply for logic elements, a voltage reference, a current reference, a bias circuit, a charge pump, a high voltage regulator, an analog to digital converter, a low-noise-amplifier, a digital to analog converter, an operational amplifier, a transconductance amplifier, a comparator, an oscillator, a phase-locked-loop, a memory, a controller, a state machine, a modulator, a mixer, a filter, or an encoder. In some implementations the IC is electronically coupled to at least one passive circuit element that is physically coupled to the scaffolding. In some implementations the integrated circuit (401) may further contain a cryptographic element to provide for encryption, decryption, hashing, obfuscation, or otherwise protecting information to be transmitted. In further implementations, the integrated circuit (401) may further be comprised of a driver to deliver electrical signals into tissue adjacent to electrodes. The driver may be an H-Bridge circuit, a cascode output stage, gm-boosted output stage, amplifier, or the like. Those knowledgeable in the art will be familiar with suitable topologies to provide for the delivery of electrical signals to tissue. In some implementations, the at least one transducer is comprised of two or more acoustic transducers communicatively coupled to the at least one integrated circuit wherein the driving of the two or more transducers occur at computed relative time delays, such that the mechanical wavefront generated from the at least one transducer is a mechanical wave that converges to a higher pressure amplitude at a focal point at some distance from the tissue adjacent to the scaffolding. In some implementations, the focal point of the pressure wave is used to at least one improve imaging resolution, modulate nervous system tissue, ablate tissue, stimulate mechano-sensitive tissue, or achieve a mechanically-mediated physiological effect.FIGS. 5A though 5D show how power from the flexural motion of the scaffolding within the body lumen may be harvested by the piezoelectric transducers that are integrated into the struts of the scaffolding. FIG. 5A represents the heart at end-diastole.

[0093] 501 is the left anterior descending (LAD) artery. FIG. 5B is a detail view of FIG. 5A showing an exposed section (502) the LAD (501) with a scaffolding (503) of an apparatus displayed therein. 503 demonstrates the position of the stent at end-diastole. Dashed outline 504 represents the position of the scaffolding at end-systole. The difference between the positions of 503 and 504 demonstrates the flexural motion of the stent within the artery during a normal cardiac cycle. Piezoelectric transducers integrated into the stent scaffolding can transduce this time-varying mechanical strain into electrical power for use by the apparatus. Correspondingly, FIG. 5C represents the heart at end-systole. The structure labeled 501 is the LAD. FIG. 5D is a detail view of FIG. 5C showing an exposed section (502) the LAD (501) with the scaffolding of the apparatus (506) implanted therein. 506 demonstrates the position of the stent at end-systole. Dotted outline 505 represents the position of the scaffolding at end-diastole. The difference between the positions of 506 and 505, equal in magnitude to that between 503 and 504, demonstrates the flexural motion of the scaffolding within the artery during a normal cardiac cycle.

[0094] Fig- 6 shows an example implementation of an impedance measurement system or impedimetric receiver, used to determine the impedance magnitude, or impedance response, of a tissue at a selected frequency. A frequency source (601) generates a digital sinusoidal reference waveform at a selected frequency. For example, the frequency source (601) may comprise a voltage-controlled oscillator (VCO), a numerically controlled oscillator (NCO), a direct digital frequency synthesis (DDS) engine, or any digitally-controlled oscillator that produces a digital representation of a sinusoid at the selected frequency.

[0095] The frequency source (601) is electrically coupled to a digital-to-analog converter (DAC) (602) that converts the digital sinusoid into an analog excitation waveform. The output of the DAC (602) is a time-varying analog voltage or current proportional to the instantaneous value of the synthesized sinusoid generated by the frequency source (601). The analog excitation waveform from the DAC (602) drives an output driver (603). In some implementations, the DAC (602) may generate a voltage waveform that is subsequently converted to a current by the output driver (603); in other implementations the DAC (602) may directly control an output driver (603), e.g., a current-output driverstage. The output driver (603) is configured to apply a controlled stimulus to a tissue via one or more electrodes (604). In a representative implementation, the output driver comprises a constant-current driver that injects a sinusoidal stimulus current at the selected frequency into a tissue to be measured through one or more electrodes. In this implementation the output driver (603) is acting as a stimulator. In a further implementation the output driver comprises a constant-voltage driver that injects a sinusoidal stimulus voltage at the selected frequency into the tissue to be measured through one or more electrodes. In the exemplary implementation, the output driver (603) includes sufficient compliance to maintain the selected stimulus across the expected range of tissue impedances without saturating, and may further include safety features such as current limiting, voltage compliance limiting, and fault detection.

[0096] The at least one electrode (604) and tissue present a complex impedance that converts the applied stimulus sinusoid into a corresponding sinusoidal response.

[0097] Depending on the chosen output driver (603) topology, the response may be observed as a voltage developed across the tissue / electrode path, a current flowing through the path, or both. Accordingly, an analog-front-end sensing stage (605) senses at least one of a tissue voltage or a tissue current. In the exemplary implementation, the tissue and electrodes (604) are driven with a known stimulus current using the output driver (603) and the analog-front-end senses the resulting voltage. A further mode of operation is comprised of an output driver (603) delivering a known sinusoidal stimulus voltage and sensing the corresponding sinusoidal current. In a further implementation, both voltage and current are sensed by sensing with multiple electrodes, or by time-multiplexing measurements at one electrode, or both, so that both quantities are measured.

[0098] The output of the sensing stage (605) is further processed with a tunable bandpass filter (606). The band-pass filter (606) allows a range of frequencies that includes the selected excitation frequency to electrically couple to the peak-amplitude detector (607), while attenuating or blocking out-of-band noise and interference. This ensures that the input to the peak-amplitude detection (607) system is predominantly comprised of information about the tissue response at the excitation frequency. In implementations that sweep the selected input frequency, the band-pass filter (606) may be further comprised of a switched filter bank with multiple center frequencies, a singular filter with a tunable center frequency, or a sufficiently wide pass-band frequency response to accommodate all anticipated frequencies of interest while providing attenuation outside of the range of interest.The filtered signal is converted to a low-frequency or DC quantity proportional to its peak amplitude from the peak-amplitude detector (607). In one implementation, a peak-amplitude detector is used to track and hold the peak amplitude of the filtered response sinusoid. The resulting scalar value from the peak-amplitude detector (607) is the amplitude response of the tissue to the excitation sinusoid, which gets converted to a digital code by an analog-to-digital converter (608). In one implementation, the analog-to-digital converter (ADC) samples the amplitude response a single time. In a further implementation, the ADC samples multiple times at a given selected frequency. These samples are averaged or otherwise filtered by the processing measurement (609) to improve measurement stability.

[0099] Processing the impedance measurement (609) involves receiving the digitized amplitude response measurement from the ADC (608) and computing an impedance magnitude corresponding to the selected excitation frequency generated by the frequency source (601) (601). In an implementation in which a known stimulus current is driven, for example, using an output driver (603) that is a constant-current output driver and a sensing stage (605) to sense voltage amplitude, the impedance magnitude at the selected frequency is processed (609) as the known current output amplitude delivered by the output driver (603) and the sensed voltage amplitude detected by a front end the voltage sensing stage (605). This provides for determination of the amplitude response of the impedance.

[0100] In a further implementation, a precision comparator is used alongside the peakamplitude detector (607) to infer the precise timing of the amplitude response peak.

[0101] Determining the relationship of the peak of the excitation sinusoid to the peak of the response sinusoid using information from the frequency source (601) and the comparator may provide phase response information that can be used to further determine the complex impedance characteristics of the tissue.

[0102] In a further implementation, a controllable analog oscillator subsumes the function of both the frequency source (601), e.g., a digitally-controlled oscillator, and the DAC (602). In a further implementation, a lock-in amplifier is used to determine the electromagnetic amplitude response and the electromagnetic phase response, allowing for more precise computation of the complex impedance.

[0103] The measured electromagnetic amplitude response and electromagnetic phase response can, in some embodiments, be used to infer information about the tissue, interaction between the apparatus and the tissue, interaction among at least twoapparatuses in an assembly, and the structural and functional integrity and configuration of the scaffolding and at least one flexible membrane, if applicable, comprising the apparatus.

[0104] In a further implementation, the output driver (603) delivers an electromagnetic pulse or wave with an arbitrary waveform shape, providing electrophysiological stimulation to tissue adjacent to the electrode. In some implementations the stimulator may provide at least one therapeutic benefits, affect tissue around the electrode, or characterize the tissue surrounding the electrode. In some implementations the stimulator may serve multiple functions.

[0105] FIG. 7 shows one implementation of the apparatus in illustrative complex anatomy. The main body of the scaffolding of the apparatus (710) is inserted into the aorta (701). Below the bifurcation (711), in which the tubular portion of the scaffolding splits into two or more tubular portions, the right limb of the scaffolding (712) is inserted into the right iliac artery (702). The left limb of the scaffolding (713) is short, and has an opening for a second member of an assembly, a stent graft (714), placed in the left iliac artery (702). Preservation of circulation to branch vessels can be accomplished in a diversity of ways. A chimney (718), which comprises a channel through the branch vessel (717) that continues on within the body of the scaffolding, is used in one branch vessel (715). A side arm (716) emerges directly from the body of the scaffolding. A fenestration (725) is an opening in the body of the scaffolding that allows blood to flow into the branch vessel (715). A landing zone (719) is a location designated by the clinician for a tight seal between the scaffolding and the inner wall of the body lumen. If the seal is not tight, it may result in an endoleak, in which the tissue volume of interest is not fully excluded from the fluid circulation. Tissue volumes that are typically excluded from circulation, and illustrated here, include an aneurysm (705), which is an outpouching of an intimal layer of the artery (703), a pseudoaneurysm (706), in which the intima is tom, and the fluid is contained within an adventitia (704). A tear or rupture (707) is not contained; a tear or rupture might lead to a hematoma. A dissection involves the formation of a false lumen (708), into which fluid may enter (709). A variety of endoleaks are illustrated. A Type I endoleak (720) typically arises at the landing zone. A Type II endoleak (722) results from flow of fluid into the excluded tissue volume from a branch vessel. A Type III endoleak (723) results from flow into the excluded tissue volume from the fluidly communicative passageway (710, 712, 713, 714) due to a breakin the scaffolding or a membrane or due to failure in the seal (724) between apparatuses in the assembly.

[0106] FIGS. 8A through 8D illustrate an example of the wireless exchange of energy and information between the apparatus implanted within the body and an external system or device, external to the body. FIG. 8A shows a patient holding the external device (801) to his chest. FIG. 8B is an expanded view of the external device (801). Arrows schematically illustrate the bidirectional exchange of information (802) and the transmission of power (803) between the external device and the apparatus deployed within the LAD of the patient. FIG. 8C is an exposed view of the heart of the patient. The LAD (804) of the heart is shown. FIG. 8D shows an exposed section (805) of the LAD (804) with the apparatus (806) comprised of a scaffolding with one or more flexible membranes implanted within the lumen of the LAD, the apparatus receiving power and exchanging information with the external system illustrated in FIG. 8B. In some implementations, the external system comprise or be communicatively coupled to at least one of: a smart cellular phone, a tablet device, a personal computer, a data hub, a cloud connected device, a switch or router, or a server hosting an electronic medical record system.

[0107] FIG. 9 shows part of one implementation of a software algorithm for operation on the at least one IC and on external devices and systems communicatively linked to the at least one IC. The set of transducers (901) comprises acoustic or ultrasonic transducers (905), which are typically PMUTs and CMUTs (i.e. reversible electromechanical transducers). These are electrically coupled to the interface hardware (906) shown in greater detail in FIGs. 4A-4E. Some implementations include other transducers (904), including pressure sensors, optical or electromagnetic transducers (such as light-emitting diodes, VCSELs, photodiodes, SPADs, and electromagnetic radiators), electrodes (for the detection of bioelectrical signals or for an impedimetric receiver), and at least one transmission line with electrical components, i.e. resistors, capacitors and inductors, either as discrete components or as impedances associated with the transmission line itself). In this implementation, the data from the interface hardware (906), e.g., ultrasound / acoustic interface, is processed to obtain B-mode (908) and Doppler (909) images according to methods familiar to those knowledgeable in the art. Superimposing these can produce duplex ultrasound images. In other implementations, A mode, M mode, compressive sensing, harmonic imaging, elastography, or shear wave imaging may be used. These images are combined with data from the other transducers (904) to supportthe tools in the Implant Toolbox (902), the suite of tools that may be used by the clinician when inserting the apparatus into the body lumen. These include endoleak detection (910), scaffold expansion measurement (911), relative position ascertainment (912) in cases when multiple apparatuses are being used in an assembly, and assembly protocols (913) to algorithmically confirm the expected placement of the apparatuses within the assembly and within the body lumen (e.g., to confirm apposition to the inner wall of the lumen). Besides implantation, the range of imaging outcomes that are of clinical interest include prosthesis migration, dislodgement of apparatuses within an assembly, aneurysmal sac diameter determination, aneurysmal sac enlargement, endoleaks, and damage to the apparatus or assembly. An artificial intelligence / machine learning algorithm performed in the external system can identify these in some implementations. Data from the other transducers (904) may improve the accuracy of these algorithms (903). In most implementations, each processing step on the at least one integrated circuit involves subjecting the signal comprising the data, by the at least one integrated circuit, to a linear or nonlinear transformation such that the information is enriched with respect to statistical noise. The Mean Pressure Index, a ratio of the aneurysmal sac pressure to the pressure within the fluidly communicative passage after the aneurysmal sac is excluded from the fluid circulation, has been studied and is of clinical interest for its predictive power. In hardware implementations where pressure sensors or electromechanical transducers are physically coupled to both the adluminal and abluminal aspects of the scaffolding or flexible membrane, it is possible to calculate the Mean Pressure Index (907), which may facilitate more accurate determination of risk (14). Both raw and processed (903) imaging data and data from the other transducers (904) can be used to predict the risk of adverse clinical outcomes (14). For aneurysms, this includes aneurysm sac expansion or rupture. For pseudoaneurysms, it includes a pseudoaneurysm expansion or rupture or a recurrent pseudoaneurysm. For an arteriovenous fistula, it includes aneurysmal degradation. Imaging data, both original (908, 909) and processed (903), raw data from the transducers (904), and derived outcome prediction data (14) can be sent to the patient, clinician or a third party at regular intervals, upon request, or when the data take certain values (alert conditions).

[0108] FIG. 10 is a flowchart illustrating an example implementation of the processes for measuring acute and chronic changes in the vessel in which the apparatus is deployed; detecting damage to the structural integrity of the scaffolding or membranes; alerting clinicians, caregivers, patients and, if required, emergency medical services, to urgent orimportant structural and functional changes detected by the apparatus; storing direct or derived measurements in memory; accessing device memory; displaying measured and derived data; and uploading measured and derived data to electronic medical records (EMRs). The set of transducers (1001) comprises acoustic or ultrasonic transducers (1006), which are typically PMUTs and CMUTs (i.e. reversible electromechanical transducers). These are electrically coupled to the interface hardware (1007) shown in greater detail in FIG. 4. Some implementations include other transducers (1005), such as pressure sensors, optical or electromagnetic transducers (e.g. light-emitting diodes, VCSELs, photodiodes, SPADs, and electromagnetic radiators), electrodes (for the detection of bioelectrical signals or for an impedimetric receiver), and at least one transmission line with electrical components (resistors, capacitors and inductors, either as discrete components or as impedances associated with the transmission line itself). In some implementations, the data are collected synchronously (1004) with a periodic or aperiodic signal from the body, and that signal may be measured by the electrode or another transducer. For example, in the case of a covered stent in a leg artery, electromyography data from the electrodes can be used to selectively measure lower extremity arterial pressure at rest. In the illustrated implementation, collection of synchronous data takes the form of gating of data such that data only at specific times is utilized; gating data may be an advantageous approach for collection of data from transducers that do not require much energy to convert into a signal. However, this collecting synchronous data can also be achieved in some implementations by driving the transducers at times that are synchronous to the periodic or aperiodic signal from the body.

[0109] If any alert conditions are met by the processed or directly-measured data, as shown in FIGs. HA and 11B, or the break / tear detection procedure (FIG. 12) identifies a compromise to the structural integrity or continuity of the scaffolding or flexible membrane, an alert process from the alert stack (1002) is activated. The alert is transmitted via the internet or a local network, from the external device; a mobile device, a tablet device, a personal computer, or a switch or router, each connected to the external device; a cloud-connected device; or a data hub; to the server network hosting the EMR system used by the clinician treating the patient; the clinician receives the alert on the EMR (1016). In the preferred implementation, it is also transmitted through a cellular or local network to the patient’s mobile device in the form of a text or voice message, or a notification within a software application on the mobile device (1017). The patient’scaregiver or caregivers may also elect to receive notifications (1018). In some implementations, the alert may be sent to an off-site monitoring center server (1019). Other alert options may be selected, including e-mail sent from the external system through the internet (1020). Some individuals, including the patient, or the at least one caregiver, clinician or monitoring center employee may be privileged in the software (1028) to evaluate the urgency of the alert and activate emergency medical services (1030) or to defer action (1029). In the latter case, in the preferred implementation, the alert would still be noted in the EMR and the monitoring center would still be notified, if applicable. In other implementations, emergency medical services may be summoned directly by the external system though the internet or a telephone line. In some implementations, an alert can be sent for detection of acute coronary syndrome by the integrated circuit or external system based on information collected by electrodes or by chemical sensors for troponin or myoglobin, scaffold breakage / flexible membrane tear (FIG. 12), patient falls, electronics malfunctions, variations in blood glucose, prosthesis migration, dislodgement of apparatuses within an assembly, aneurysmal sac enlargement, endoleaks, etc. Actions for each alert (e.g. a different set of devices receiving notifications) could be specified.

[0110] A clinician interface (1003) is a piece of software that, among other functions listed herein, allows for the selection of these presets on an external personal computer or mobile device, or, in some implementations, a dedicated external device for clinician use (1021). The clinician interface may or may not be integrated with the EMR software on the device on which it is being utilized. Via the clinician interface (1003), the treating clinician may activate a state on the apparatus wherein the intraluminal pressures measured by the transducers, and especially the ratio of the sensor readings in the proximal and distal portions of the prosthesis are measured, and these values, and / or filtered derivatives thereof (e.g. moving averages), are calculated and transmitted back to the device hosting the clinician interface (1003) for display in real time (1022), described here as “FFR mode” (1024). Another mode accessible through the clinician interface in the preferred implementation is “clinical-implant mode” (1025), which, when activated, causes data from the transducers about contact with the inner wall of the lumen and the configuration of the scaffolding, and derivatives thereof, to be transmitted to the device hosting the clinician interface (1003) and displayed in real time (1022), along with other tools from the Implant Toolbox (902). In “FFR mode” and “clinical-implant mode,” measurements are taken by the transducers, passed to the IC, transmitted wirelessly to theexternal device, and then to the device hosting the clinician interface, if applicable.

[0111] Calculation of derivative values (e.g. moving averages), may be performed on any of these devices. Two- or 3 -dimensional images that are interpretable by clinicians may be generated from data recorded by electro-optical and acoustic transducers on any of these devices and displayed in real time (1022). Finally, some or all measured values and derivatives thereof are stored in memory (1026), either on the apparatus, the external system, a server hosting the EMR, a mobile device connected to the external device, or another device connected via network protocols familiar to those knowledgeable in the art. The values to be stored are specified by the clinician. In the preferred implementation, the clinician interface can query the memory (1023) and display historical measured and derived values displayed in real time (1022) as well as real-time values from all the transducers (1001). Derived values may be recalculated from stored measured values. Values uploaded to the servers hosting the EMR (1027) may also be viewed by clinicians who do not have access to the clinician interface.

[0112] FIG. 11A is a flowchart showing an implementation that autonomously tracks a biomarker, physiological parameter, or statistically derived metric, such as a weighted moving average, over time, and notifies a patient, clinician, or third party when a detected or derived value exceeds an alert threshold. These data are optionally stored to track values over time. An initial measured or derived value and an initial bounding threshold are established (1101). The at least one integrated circuit waits for a specified period of time (1102), during which energy is harvested from the human or animal body to provide sufficient power to take the measurement from the at least one transducer. When the implant wakes up, new samples are taken and statistically derived parameters are updated with new values (1103). The values are compared against a fixed threshold, range, or a statistically derived threshold, or range, such as a multiple of an adaptive noise floor (1104) If the value exceeds the thresholds, an alert condition is raised to the external system, ultimately alerting a patient or physician (1105). After the alerts are issued the apparatus goes back to its low-power state to harvest power (1102). If the recorded datum is within the normal range at 1104, the apparatus goes back to its low-power state (1102). FIG. 11B shows a time series representation of the information and the relevant statistically-derived thresholds (1106). The data trace (1107), is displayed with its calculated mean (1108) and a normal range (1109). When a datum (1110) exceeds the threshold range (1109), an error condition, alert, or warning is delivered to the external system or device.FIG. 12 is a flowchart showing one implementation of the method for detection of breakage of the scaffolding or tear of a flexible membrane. A response of the scaffolding or membrane to mechanical perturbation (here, an impulse) introduced into the scaffolding by a reversible electromechanical transducer is measured by the same or a different reversible electromechanical transducer, and the data are collected by the IC via a transducer interface. The measured signal is shown (1201), with the impulse (1202), the response of the scaffolding or membrane when the scaffolding or membrane is intact (1203) and the response of the scaffolding or membrane when the scaffolding or membrane is damaged (1204). The measured data may optionally undergo a nonlinear transform, such as processing by a deep neural network, projection onto nonlinear basis functions, or another nonlinear transform familiar to those knowledgeable in the art (1205). The results are then processed by a classifier (1206) which separates the responses associated with apparatus damage from those associated with apparatus integrity according to a hyperplane (1207) of one or more dimensions. If a break or tear is detected (1208), then at least one of the clinician, the patient, or a third-party is alerted according to the settings of the device and any modifications to the software regime are initiated (1209). If no break or tear is detected, then the integrity of the apparatus will reinterrogated after some preset or variable time.

[0113] FIG. 13 is a flow chart that outlines the typical usage model for the preferred implementation. The apparatus starts up (1301) during the deployment into the lumen of the body, after which it begins to harvest energy from its environment, (1302). The apparatus will continue to harvest energy continuously, however, when an operational command (1319) is to be issued to the apparatus, and an external system is brought proximal to the apparatus (1320), the at least one transmitter of the apparatus becomes communicatively linked to the external system, and the external system provides supplemental power to the apparatus. The apparatus will detect this external system as it becomes communicatively coupled with the apparatus in (1303), and be operational to accept the wireless power, further energizing the integrated circuit (1310), which is converted to at least a usable direct-current system voltage through a power converter, power receiver, or power recoverer. It is possible that the external system, device, or method configured to provide wireless power will also transmit, via a communicative link or through modulation of the power link itself, a command (1319) to the apparatus. The decision tree is thus elucidated in (1311): if a command has not been received, the system will return to harvesting power from its environment, and will continue accepting externalpower if still available. However, if a command sequence is detected, the command is validated and decoded (1312), and the apparatus will implement an action to follow the command (1313). The command sequence may require the apparatus to transmit data that is stored on the apparatus in memory, in which case the data are read, packaged into a packet, and transmitted via the one or more transmitter (1314). Alternatively, the command may request that the apparatus take a measurement. In some cases, the external system may request readings of the supplies, bias points, and status of the electronic systems of the apparatus, in which case this information is the data transmitted by the at least one transmitter back to the external system in (1316). In other cases, the external system may request a reading from the at least one transducer. The apparatus may receive a signal from at least one of the transducers (1315). The information received is packaged and transmitted to the external system by the at least one transmitter (1316).

[0114] Alternatively, the command may be to provide some effect on the apparatus. In this case, the appropriate transducers are selected and driven to elicit the desired effect (1317), after which a confirmation or result is sent to the external system by the at least one transmitter (1316). In most implementations, the apparatus responds with acknowledgement and result of the command. The apparatus then returns to harvesting energy, (1302), and may continue to receive wireless energy via the integrated circuit (1310), and further commands (1311) as dictated by the external system, device, or method. If no external system, device, or method is providing power or interacting with the apparatus, the apparatus will periodically check whether the supplies are stabilized and check for a scheduled action, (1304). For instance, in the preferred implementation the apparatus wakes up at a regular intervals to take at receive information from the at least one transducer, assess the stability of the system voltage and biases in the electronic system of the apparatus, or provide some effect, (1304). The apparatus performs a function (1305) if doing so will not brown-out or otherwise deplete the charge powering the apparatus, and the apparatus will perform a function if the integrated circuit determines that sufficient charge is available to complete the function in its entirety. If these stipulations are not met, in the best implementation, the apparatus will return to continuously harvesting energy (1302) until these conditions are satisfied. When sufficient charge is available to complete the function in its entirety, the device will either receive information from the one or more transducers, (1306), and store the result of in memory (1307), or provide some effect (1308), and record the effect and any data surrounding the effect that are germane to the operation (1309). Upon completion of the action, the integrated circuitwill schedule the next action (1318). The apparatus then goes back to harvesting energy, (1302), until an external interaction occurs (1303), or until the conditions for a scheduled measurement or effect are met (1304).

[0115] FIG. 14A shows a training of a machine learning algorithm for the prediction of clinical outcomes, including an aneurysmal sac expansion or rupture, a pseudoaneurysm expansion or rupture, a recurrent pseudoaneurysm or tear in a body lumen, or an aneurysmal degradation. Multidimensional structural and functional data (1404) collected by the transducers of at least two individuals (1406, 1407), with at least one apparatus deployed in a body lumen of each of their respective bodies, is transmitted to and stored on an external system (1414). Each figure in column 1404 represents a set of multidimensional data collected from a single individual, 1406 representing individuals with one implanted apparatus, 1407 representing individuals with two implanted apparatuses. The multidimensional structural and functional data (1404) is a predictor variable. The categorical or continuous real-world outcome data (1405) are likewise stored in the external system (1414). 1408 represents a good clinical outcome, 1409 represents a bad clinical outcome corresponding to the individual on that row (1406, 1407). These outcomes may be a stable disease, an improvement in a disease, or an aneurysmal sac expansion or rupture, a a pseudoaneurysm expansion or rupture, a recurrent pseudoaneurysm or tear in the body lumen, or an aneurysmal degradation. Collectively, the structural and functional data (1404) and the outcome data (1405) comprise training data (1401). In some implementations, the data are subjected to a linear or nonlinear transformation such that the the information is enriched with respect to statistical noise. Using techniques familiar to those knowledgeable in the art, a classifier (1402) can be trained to classify an arbitrary set of structural or functional data based on its expected categorical outcome. In some implementations, this is accomplished by constructing a multidimensional hyperplane (1410) through the space of predictor data. Alternatively, if a continuous outcome variable (1411) is desired, a regression (1403) may be used instead of, or in addition to, the classifier (1402), the outcome variable (1411) a function of the multidimensional predictor variable (1412).

[0116] FIG. 14B shows the application of the classifier (1402) trained in FIG. 14A to a patient with unknown outcome (1415), in order to predict a categorical clinical outcome (1416). FIG. 14C shows the application of the regression (1403) on the data (1401) in FIG. 14A to a patient with unknown outcome (1415), in order to predict a clinical outcome (1417).FIG. 15A shows an implementation of a system comprising an assembly of an apparatus (1501) and a stent graft (1502). A length of the stent graft (1502) partially overlaps a length of the apparatus (1501). A Type III endoleak is illustrated (1503), fluid escaping into the excluded tissue volume (1518).

[0117] FIG. 15B is a section view along the section line illustrated in FIG. 15A. The Type III endoleak is depicted as the arrow between the overlapping apparatus (1501) and stent graft (1502), indicating the flow of fluid into the excluded tissue volume (1518), originally from a fluidly communicative passageway (1519) formed through the shared lumen of the stent graft and apparatus when the stent graft and apparatus are expanded within the body lumen. A transducer (1504) physically coupled to the apparatus (1501) generates a mechanical or electromagnetic wave (1505). The mechanical or electromagnetic wave (1505) travels toward and interacts with the stent graft (1502), ultimately generating a returned mechanical or electromagnetic wave (1506). The returned mechanical or electromagnetic wave (1506, 1507) carries information about the relative position of the transducer (1504) carried by the apparatus (1501) and the stent graft (1502). A returned mechanical or electromagnetic wave, which may be any combination of reflected, refracted, scattered or transmitted through the material of the stent graft, may be received by the transducer that generated the mechanical or electromagnetic wave that caused the returned mechanical or electromagnetic wave detected by the transducer (1504) or by another transducer (1508). This information is transmitted to an IC (1513) physically connected to the apparatus (1501) by a transmission line (1515). The IC (1513) also energizes the transducer (1504) on the apparatus that generates the mechanical or electromagnetic wave via the transmission line (1515). In some embodiments, a mechanical transducer (1510) is physically coupled to the stent graft (1502). A mechanical wave (1509) generated by the transducer (1508) physically coupled to the apparatus (1501) likewise results in a returned wave (1511), but the returned wave may be affected by the mechanical impedance of the transducer (1510) physically coupled to the stent graft (1502), which may in some implementations be modified by the clinician, and which may subserve more precise triangulation of the relative positions of the apparatus and the stent graft.

[0118] The information about the relative position of the transducers physically coupled to the apparatus (1504, 1508) and the stent graft (1502) is transmitted to an external device, external to the system, by a transmitter (1514) that is communicatively coupled to the IC (1513) by the transmission line (1515). The transducer (1504) physically coupledto the apparatus (1501) may also collect information about the Type III endoleak (1503) by sending a mechanical wave (1512) toward the fluid comprising the Type III endoleak (1503) and, in combination with the IC (1513) to which it is communicatively coupled, measuring the Doppler shift of a mechanical wave returned from the fluid comprising the Type III endoleak (1503).

[0119] The mechanical wave may be an acoustic or ultrasonic pulse, wave or other perturbation of arbitrary form. Information from at least two transducers may be algorithmically combined by techniques familiar to those knowledgeable in the art to infer the relative positions and configurations of the apparatus and the stent graft in multiple spatial dimensions. The information about the relative positions of the apparatus and the stent graft can then be displayed to a patient, clinician or third party in real time, or after a delay. The information may include information about contact or apposition between the apparatus and the stent graft, but, in this implementation, this information about contact or apposition is derived from the information about relative positions of the apparatus and the stent graft. The apparatus and the stent graft depicted each comprise a tubular scaffolding, the scaffolding for the stent graft visible in cross-section (1516). In this implementation, the stent graft comprises a flexible membrane (1517). Other implementations comprise a cerebral flow diverter, conventional bare-metal and drugeluting stent, fully- or partly-resorbable scaffold, or other endoluminal prosthetic apparatus, in lieu of a stent graft. The endoluminal prosthetic apparatus may, in some implementations, be inside of the apparatus when the endoluminal prosthetic apparatus and the apparatus overlap.

Claims

CLAIMSI / We claim1. An apparatus implantable in a body lumen of a body, the apparatus comprising: a scaffolding that is expandable and that includes at least a tubular portion, wherein the scaffolding is insertable into the body lumen of the body and expandable such that the scaffolding when expanded is at least in part mechanically braced against an inner wall of the body lumen and when expanded the tubular portion of the scaffolding forms a fluidly communicative passageway through the scaffolding;at least one flexible membrane physically coupled to the tubular portion of the scaffolding, when the scaffolding is expanded the at least one flexible membrane at least partially excludes a volume of tissue from a fluid circulation, the fluid circulation at least through the fluidly communicative passageway;at least one reversible electromechanical transducer, the at least one reversible electromechanical transducer physically coupled to the scaffolding and when the scaffolding is expanded, the at least one reversible electromechanical transducer is mechanically coupled to at least one of the volume of tissue at least partially excluded from the fluid circulation by the at least one membrane, the fluidly communicative passageway;at least one integrated circuit physically coupled to the scaffolding and communicatively coupled to at least one of the at least one reversible electromechanical transducer, wherein the at least one integrated circuit at least one of processes, stores or communicates information represented by at least one signal generated by the at least one reversible electromechanical transducer,at least one transmitter physically coupled to the scaffolding and communicatively coupled to the at least one integrated circuit and communicatively coupled to an external device that is external to the apparatus, wherein the at least one transmitter transmits information from the apparatus to the external device while the apparatus is implanted in the body lumen of the body.

2. The apparatus according to claim 1, wherein at least one of the scaffolding, the at least one flexible membrane, is further physically coupled to at least one of a resistor, a capacitor, an inductor that forms at least part of at least one transmission line, the at leastone transmission line communicatively coupled to the at least one integrated circuit, and electrically characterizable to infer at least one of a structural integrity, a functional integrity, or a structural expansion of at least one of the scaffolding or the at least one flexible membrane.

3. The apparatus according to claim 1, wherein the at least one flexible membrane comprises at least one of an adluminal aspect of the flexible membrane facing the fluidly communicative passageway, and an abluminal aspect of the flexible membrane facing the tissue volume at least partially excluded from circulation, or the scaffolding comprises at least one of an adluminal aspect of the scaffolding facing the fluidly communicative passageway, an abluminal aspect of the scaffolding facing the tissue volume at least partially excluded from circulation, and a side aspect of the scaffolding having a surface normal that comprises at least a component that is tangent to the tubular portion of the scaffolding, andthe at least one integrated circuit is physically coupled to at least one of:the flexible membrane on at least one of the adluminal aspect of the flexible membrane, the abluminal aspect of the flexible membrane,or to the scaffolding on at least one of the adluminal aspect of the scaffolding, the abluminal aspect of the scaffolding, or the side aspect of the scaffolding.

4. The apparatus according to claim 1, wherein at least one of the at least one flexible membrane at least in part comprises at least one of a flexible circuit board, an electromagnetic radiator, at least one electrode, or a passivated patterned circuit.

5. The apparatus according to claim 1, wherein at least one of the at least one reversible electromechanical transducer is a capacitively micromachined ultrasound transducer.

6. The apparatus according to claim 1, wherein at least one of the at least one reversible electromechanical transducer is a piezoelectric transducer.

7. The apparatus according to claim 6, wherein the at least one piezoelectric transducer is electrically coupled to the at least one integrated circuit to partly or wholly energize the at least one integrated circuit in response to stimulus applied to the at least one piezoelectric transducer from a body movement or a fluid movement.

8. The apparatus according to claim 1, further comprising an at least one electrode physically coupled to the scaffolding and operatively coupled to at least one of the at least one integrated circuit.

9. The apparatus according to claim 8 wherein at least one of the at least one integrated circuit is further comprised of an at least one stimulator, electrically coupled to drive at least one of the least one electrode with an electromagnetic pulse or wave.

10. The apparatus according to claim 9 wherein at least one of the at least one integrated circuit is further comprised at least one impedimetric receiver that is communicatively coupled to at least one of the at least one electrode and that characterizes at least one of an electromagnetic amplitude response, an electromagnetic phase response of at least one of the tissue volume at least partially excluded from fluid circulation, the fluidly communicative passageway, the fluid circulation, to the electromagnetic pulse or wave.

11. The apparatus according to claim 1, wherein the at least one integrated circuit comprises at least: a driver to energize at least one of the at least one reversible electromechanical transducer to generate a mechanical pulse or wave, and at least one interface that is communicatively coupled to at least one of the at least one reversible electromechanical transducer and that is responsive to variations in the at least one signal generated by the at least one reversible electromechanical transducer when the at least one reversible electromechanical transducer is exposed to a mechanical pulse or wave.

12. The apparatus according to claim 1, wherein the at least one scaffolding has at least one of an at least one fenestration, an at least one side arm, an at least one bifurcation, or an at least one chimney.

13. The apparatus according to claim 1, further comprising at least one chemical sensor physically coupled to the scaffolding and communicatively coupled to the at least one integrated circuit.

14. The apparatus according to claim 1, wherein the at least one transmitter is communicatively linked to an external system that at least one of powers the apparatus, receives information from the apparatus, transmits information to the apparatus, controls the apparatus.

15. The apparatus according to claim 14, wherein the at least one external system at least one of: comprises, or is further communicatively coupled to at least one of:a smart cellular phone, a tablet device, a personal computer, a data hub, a cloud connected device, a switch or router, a server hosting an electronic medical record system.

16. The apparatus according to claim 1, wherein the at least one transmitter is a part of at least one of the at least one integrated circuit.

17. A method of operation of a system comprising an apparatus to gather structural or functional information about a human body or an animal body using an expandable scaffolding that is at least in part tubular and that carries at least one flexible membrane, at least one integrated circuit, at least one reversible electromechanical transducer, and at least one transmitter, the expandable scaffolding when expanded is at least in part mechanically braced against an inner wall of a body lumen of the human body or the animal body, and when expanded the expandable scaffolding forms a fluidly communicative passageway through the expandable scaffolding, and when expanded the flexible membrane at least partially excludes a tissue volume from a fluid circulation, the fluid circulation at least through the fluidly communicative passageway, the method comprising:energizing the at least one integrated circuit;generating a mechanical pulse or wave by at least one of the at least one reversible electromechanical transducer, the mechanical pulse or wave directed toward at least one of the tissue volume at least partially excluded from the fluid circulation, the fluidly communicative passageway, the fluid circulation;receiving, by at least one of the at least one reversible electromechanical transducer, a returned mechanical pulse or wave returned from at least one of the tissue volume at least partially excluded from the fluid circulation, the fluidly communicative passageway, the fluid circulation, the returned mechanical pulse or wave representing structural or functional information about at least one of the tissue volume at least partially excluded from the fluid circulation, the fluidly communicative passageway, the fluid circulation;converting, by the at least one reversible electromechanical transducer, the returned mechanical pulse or wave into a signal;communicating the signal from the at least one reversible electromechanical transducer to the at least one integrated circuit, the signal containing structural or functional information about at least one of the tissue volume at least partially excluded from the fluid circulation, the fluidly communicative passageway, the fluid circulation; andtransmitting, by the at least one transmitter, the information about at least one of the tissue volume at least partially excluded from the fluid circulation, the fluidly communicative passageway, the fluid circulation, to an external device that is external to the apparatus.

18. The method according to claim 17, further comprising:introducing an electrical, electromagnetic, ultrasonic, or acoustic pulse or wave, into the at least one of the expandable scaffolding, the at least one membrane by at least one of the at least one reversible electromechanical transducer, at least one integrated circuit; andwherein converting into a signal comprises converting into the signal a mechanical or electrical response of the at least one of the expandable scaffolding, the at least one membrane to the electrical, electromagnetic, ultrasonic, or acoustic pulse or wave that contains information about at least one of a structural integrity of the scaffolding or the at least one membrane, a mechanical continuity of the expandable scaffolding or the at least one membrane, a degree of expansion of the expandable scaffolding, an interaction between the expandable scaffolding or the at least one membrane and the inner wall of the body lumen against which the expandable scaffolding is braced, an interaction between at least two of: the expandable scaffolding, at least one of the at least one membrane, andinferring from the signal or a value representative of the signal, information about the expandable scaffolding or the at least one membrane, the interaction between the expandable scaffolding or at least one membrane with the inner wall of the body lumen of the body against which it is braced, or the interaction between at least two of: the expandable scaffolding, at least one of the at least one membrane.

19. The method according to claim 18, whereinintroducing an electrical or electromagnetic, ultrasonic, or acoustic pulse or wave, into the at least one of the expandable scaffolding, the at least one membrane, comprisesintroducing an electrical or electromagnetic pulse or wave into a transmission line that is part of at least one of the expandable scaffolding or the at least one membrane, embedded in at least one of the expandable scaffolding or the at least one membrane, or affixed to at least one of the expandable scaffolding or the at least one membrane.

20. The method according to claim 17, further comprising at least one of storing or processing, by the integrated circuit, the information about the at least one tissue volume at least partially excluded from the fluid circulation.

21. The method according to claim 17, wherein the tissue volume at least partially excluded from fluid circulation is at least one of an aneurysm, a pseudoaneurysm, an arteriovenous fistula, a tear in the body lumen, a hematoma, a rupture, or a vascular dissection.

22. The method according to claim 17, wherein generating the mechanical pulse or wave includes generating an acoustic or ultrasonic pulse or wave.

23. The method according to claim 17, further comprising:procedurally constructing an image of the structure or a graphical representation of the function of the tissue volume at least partially excluded from fluid circulation from the converted signal according to A mode, B mode, M mode, Doppler, duplex, compressive sensing, harmonic imaging, elastography, shear wave imaging, echocardiography, or another imaging procedure.

24. The method according to claim 17, further comprising:introducing an electrical, electromagnetic, ultrasonic, or acoustic pulse or wave, into at least one of the expandable scaffolding, the at least one membrane, by at least one of the at least one reversible electromechanical transducer or the at least one integrated circuit; andwherein converting into a signal comprises converting into the signal a mechanical or electrical response of at least one of the expandable scaffolding, the at least one membrane, to the electrical, electromagnetic, ultrasonic, or acoustic pulse or wave that contains information about at least one of a structural integrity of at least one of the expandable scaffolding, the at least one membrane, a mechanical continuity of at least one of the expandable scaffolding, the at least one membrane, a degree of expansion ofthe expandable scaffolding, an interaction between the expandable scaffolding and the inner wall of the body lumen against which the expandable scaffolding is braced.

25. The method according to claim 17, wherein communicating the signal containing structural or functional information about the tissue volume at least partially excluded from the fluid circulation comprises communicating the signal containing at least information from which is subsequently inferred: an aneurysmal sac diameter, an aneurysmal sac cross-sectional area, a shear wave speed, a real and a complex shear modulus, an elastic modulus, a bulk modulus, a viscosity, a relaxation time, a shear wave attenuation, a strain resulting from a mechanical pulse or wave introduced into the tissue volume at least partially excluded from the fluid circulation, a stiffness, an aneurysmal sac volume, an endoleak presence, an endoleak flow, or a flow through a tear in the body lumen or arteriovenous fistula, or any preceding parameters measured along at least one specified axis.

26. The method according to claim 17, further comprising converting, by at least one of the at least one reversible electromechanical transducer, or an at least one pressure sensor, pressure at at least one point in space in the tissue volume at least partially excluded from the fluid circulation.

27. The method according to claim 17, further comprising converting, by at least one of the at least one reversible electromechanical transducer, or an at least one pressure sensor, pressure at at least one point in space in the fluidly communicative passageway.

28. The method according to claim 17, further comprising: receiving, by at least one of the at least one reversible electromechanical transducer, a returned mechanical pulse or wave returned from at least one of at least one endoleak, an aneurysm, a pseudoaneurysm, an arteriovenous fistula, a tear in the body lumen, or a vascular dissection, the returned mechanical pulse or wave representing information about at least one of a position, flow rate, flow direction, size, elasticity, viscoelasticity, change in flow rate, change in size, change in elasticity, change in viscoelasticity of the at least one of the at least one endoleak, aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection, andwherein converting into a signal, by at least one of the at least one reversible electromechanical transducer, includes converting the returned mechanical pulse or wave,by the at least one reversible electromechanical transducer, into a signal that characterizes the at least one of the at least one endoleak, aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection; andwherein transmitting comprises transmitting, by the transmitter, the information about the at least one of the at least one endoleak, aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection.

29. The method according to claim 28, wherein transmitting, by the transmitter, the information about at least one of the at least one endoleak, aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection comprises transmitting at least one of:latency information from which a Doppler shift in the mechanical pulse or wave attributable to the flow of a fluid or a movement of an anatomical structure is inferred, or a measure of fluid flow or movement of an anatomical structure calculated from a Doppler shift in the mechanical pulse or wave inferred from the latency information, wherein calculating is performed on the at least one integrated circuit, oramplitude and latency information in the mechanical pulse or wave from which structural or functional information about the anatomical structure is inferred,a measure of anatomical structure position calculated from the amplitude and latency information in the mechanical pulse or wave, wherein the calculation is performed on the at least one integrated circuit, ora response to a shear wave, the shear wave applied to an anatomical structure, in the mechanical pulse or wave from which structural or functional information about the elasticity or viscoelasticity of the anatomical structure is inferred, ora measure of elasticity or viscoelasticity calculated from a response to a shear wave, the shear wave applied to an anatomical structure, in the mechanical pulse or wave, wherein the calculation is performed on the at least one integrated circuit.

30. The method according to claim 17, further comprising:introducing at least one of a shear wave or a compressive force, into at least one of the tissue volume at least partially excluded from the fluid circulation or the fluidly communicative passageway by at least one of the at least one reversible electromechanical transducer; andintroducing an ultrasonic or acoustic pulse or wave into at least one of the tissuevolume at least partially excluded from the fluid circulation or the fluidly communicative passageway by at least one of the at least one reversible electromechanical transducer; andwherein converting into a signal comprises converting into the signal a mechanical response of at least one of the tissue volume at least partially excluded from the fluid circulation or the fluidly communicative passageway to the ultrasonic or acoustic pulse or wave, as deformed by the shear wave or the compressive force, that contains information about at least one of the tissue volume at least partially excluded from the fluid circulation or the fluidly communicative passageway.

31. The method of operation of the system of claim 17 further comprising: generating a charge, by at least one of the at least one reversible electromechanical transducers, in response to a stimulus applied to the at least one reversible electromechanical transducer by movement of or within the human body or the animal body,and wherein energizing the at least one integrated circuit includes supplying at least part of the charge to operate the at least one integrated circuit.

32. The method of operation of the system of claim 17, the system wherein at least one of the at least one reversible electromechanical transducer comprises a load-bearing member of the expandable scaffolding, the method further comprising:generating a charge, by the at least one reversible electromechanical transducer in response to a stimulus applied to the at least one reversible electromechanical transducer by movement of or within the human body or the animal body,and wherein energizing the at least one integrated circuit includes supplying at least part of the charge to operate the at least one integrated circuit.

33. The method according to claim 23, the method further comprising: combining the information that is converted into the signal by the at least one reversible electromechanical transducer from at least two mechanical pulses or waves to achieve at least one of: higher spatial image resolution, greater image signal-to-noise ratio, combination of components of an image obtained through generation of each of the at least two pulses or waves by a varying subset of the at least one reversible electromechanical transducer, or combination of components of an image obtained byconverting each of the at least two mechanical pulses or waves into a signal by a varying subset of the at least one reversible electromechanical transducer.

34. The method according to any one of claims 23, 24, 30, and 33, further comprising:subjecting the converted signal, by the at least one integrated circuit, to a linear or nonlinear transformation such that the information is enriched with respect to statistical noise.

35. A method of operation of a system comprising an apparatus to characterize a risk of at least one of: an aneurysmal sac expansion or rupture, a pseudoaneurysm expansion or rupture, a recurrent pseudoaneurysm or tear in a body lumen, or an aneurysmal degradation, the apparatus comprising at least one expandable scaffolding that is at least in part tubular and that carries at least one integrated circuit, at least one transducer, and at least one transmitter, the expandable scaffolding when expanded is at least in part mechanically braced against an inner wall of a body lumen of a human body or an animal body, and when expanded the expandable scaffolding forms a fluidly communicative passageway through the expandable scaffolding, and when expanded the expandable scaffolding at least partially excludes at least one of an aneurysm, a pseudoaneurysm, an arteriovenous fistula, a tear in the body lumen, or a vascular dissection from a fluid circulation, the fluid circulation at least through the fluidly communicative passageway, the method comprising:energizing the at least one integrated circuit;generating a pulse or wave by at least one of the at least one transducer, converting into a signal, by at least one of the at least one transducer, a set of structural or functional information from the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection that is at least partially excluded from the fluid circulation;communicating the signal from the at least one transducer to the integrated circuit, the signal which characterizes the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection;transmitting, by the transmitter, the structural or functional information about the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection to an external device that is external to the apparatus; andprocessing the structural or functional information about the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection by subjecting the information to a linear or nonlinear transform such that the structural or functional information about the risk of at least one of: the aneurysmal sac expansion or rupture, the pseudoaneurysm expansion or rupture, the recurrent pseudoaneurysm or tear in the body lumen, or the aneurysmal degradation, is enriched with respect to statistical noise, by at least one of: at least one of the at least one integrated circuit, or at least a system external to the human or animal body.

36. The method according to claim 35, further comprisingpositioning the expandable scaffolding over the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection, the expandable scaffolding when expanded that at least partially excludes from the fluid circulation the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection; andafter positioning the expandable scaffolding, expanding the expandable scaffolding to at least partly exclude the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection from the fluid circulation.

37. The method according to claim 36, wherein the at least one expandable scaffolding carries at least one flexible membrane, the partially excluding from the fluid circulation the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection includes: blocking the fluid circulation from the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection, the blocking of the fluid circulation from the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection by the at least one flexible membrane.

38. The method according to claim 35, wherein the at least one transducer comprises at least one of: a piezoelectric transducer or a capacitive micromachined ultrasound transducer, and the converting into a signal comprises converting at least one of an acoustic response or an ultrasonic response containing the structural or functional information about the aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the bodylumen, or vascular dissection at least partially excluded from the fluid circulation into a signal.

39. The method according to claim 35, wherein the at least one transducer comprises at least one electrode, and the converting into a signal comprises converting an electrical response containing an impedance response into a signal, the impedance response containing the structural or functional information about the aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection at least partially excluded from the fluid circulation.

40. The method according to claim 35, wherein converting into a signal comprises converting into a signal by at least one of the at least one transducer that generated the pulse or wave.

41. The method according to claim 35, wherein converting into a signal comprises converting into a signal by at least one of the at least one transducer that did not generate the pulse or wave.

42. The method according to claim 35, wherein converting into a signal, by at least one of the at least one transducer, mechanical information from the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection that is at least partially excluded from the fluid circulation, includes converting into a signal, by at least one of the at least one transducer, at least one of a measure of, a value representative of, or a derivative of at least one of:a pressure;a pressure relative to a pressure measured at at least one point in space in the fluidly communicative passageway;an intensity of a mechanical pulse or wave returned from the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection that is at least partially excluded from the fluid circulation, and surrounding anatomical structures in their native state, and generated by: at least one of the at least one mechanical transducer that is converting the signal, or at least one of the at least one mechanical transducer other than the at least one mechanical transducer that is converting the signal;a latency, relative to an expected latency of a mechanical pulse or wave travelingthrough stationary tissue, of a mechanical pulse or wave returned from the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection that is at least partially excluded from the fluid circulation, and surrounding anatomical structures, and generated by: at least one of the at least one mechanical transducer that is converting the signal, or at least one of the at least one mechanical transducer other than the at least one mechanical transducer that is converting the signal; andan intensity of a mechanical pulse or wave returned from at least a point in space, relative to the expected intensity of the pulse or wave hypothetically returned from a set of points in space proximate to the point, in the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection that is at least partially excluded from the fluid circulation, and surrounding tissue, while interacting with a mechanical displacement wave, the mechanical pulse or wave generated by: at least one of the at least one mechanical transducer that is converting the signal, or at least one of the at least one mechanical transducer other than the at least one mechanical transducer that is converting the signal, and the mechanical displacement wave generated by: at least one of the at least one mechanical transducer that is converting the signal, or at least one of the at least one mechanical transducer other than the at least one mechanical transducer that is converting the signal.

43. The method according to claim 35, wherein subjecting the signal to a linear or nonlinear transform includes inputting the signal to a predictive model trained on data from humans or animals with at least two of:a stable disease,an improvement in a disease, orone or more of: an aneurysmal sac expansion or rupture, a pseudoaneurysm expansion or rupture, a recurrent pseudoaneurysm or tear in the body lumen, or an aneurysmal degradation.

44. The method according to claim 35, the method further comprising: storing, on at least one external system at least external to the human body or the animal body, the structural or functional information about the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection within the human body or the animal body;storing, on the at least one external system, a structural or functional information about an at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection within a second human body or a second animal body, the second human body or second animal body in which a mechanical scaffolding of a second apparatus is at least partly mechanically braced against an inner wall of a body lumen; constructing a predictive model that predicts a probability of at least one of: an aneurysmal sac expansion or rupture, a pseudoaneurysm expansion or rupture, a recurrent pseudoaneurysm or tear in the body lumen, or an aneurysmal degradation by using a set of training data comprising at least the structural or functional information about the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection within the human body or the animal body, the structural or functional information on the external system, and the structural or functional information about the at least one aneurysm, pseudoaneurysm, arteriovenous fistula, tear in the body lumen, or vascular dissection within the second human body or the second animal body, the structural or functional information on the external system.

45. A system implantable in a body lumen of a body, the system comprising at least two scaffoldings that are expandable and that each include at least a tubular portion, wherein each scaffolding is insertable into the body lumen of the body and expandable such that the scaffolding when expanded is at least in part mechanically braced against an inner wall of the body lumen and when expanded the tubular portion of the scaffolding forms a fluidly communicative passageway through the scaffolding, each scaffolding further physically coupled to:at least one transducer, the at least one transducer is mechanically, electrically or electromagnetically coupled to at least one other transducer on a different scaffolding from the at least one transducer;at least one integrated circuit, the at least one integrated circuit comprises at least one of: a driver to energize the at least one transducer to generate a mechanical, electrical or electromagnetic pulse or wave, at least one interface that is communicatively coupled to the at least one transducer and that is responsive to variations in a signal generated by the at least one transducer when the at least one transducer is exposed to a mechanical, electrical or electromagnetic pulse or wave; andat least one transmitter communicatively coupled to the at least one integrated circuit and communicatively coupled to an external device that is external to the system,wherein the at least one transmitter transmits information from the at least one integrated circuit to the external device while the system is implanted in the body lumen of the body.

46. The system according to claim 45, wherein an at least one flexible membrane is physically coupled to the tubular portion of at least one of the at least one scaffolding, and wherein when the scaffolding is expanded, the flexible membrane at least partially excludes a volume of tissue from a fluid circulation, the fluid circulation at least through the fluidly communicative passageway.

47. A method of operation of a system to gather structural or functional information about an assembly of at least two endoluminal prosthetic apparatuses, each of the at least two endoluminal prosthetic apparatuses respectively comprising at least a scaffolding, at least one integrated circuit, at least one transducer, and at least one transmitter, the at least one integrated circuit, the at least one transducer, and the at least one transmitter physically coupled to the respective scaffolding, each scaffolding when expanded is at least in part mechanically braced against an inner wall of a body lumen of a human body or an animal body, the method comprising:energizing the at least one integrated circuit on the scaffolding of at least one apparatus to drive the at least one transducer physically coupled to the scaffolding;generating a mechanical, electrical or electromagnetic pulse or wave by at least one of the at least one transducer physically coupled to the scaffolding, the mechanical, electrical or electromagnetic pulse or wave directed toward at least one transducer on the scaffolding on the at least one of the at least two apparatuses at least different from the apparatus comprising the scaffolding physically coupled to the at least one transducer that generated the mechanical, electrical or electromagnetic pulse or wave,receiving, by the at least one transducer toward which the mechanical, electrical or electromagnetic pulse or wave was directed, the mechanical, electrical or electromagnetic pulse or wave, the mechanical, electrical or electromagnetic pulse or wave representing information about a relative position of each of the at least one transducer that generated the mechanical, electrical or electromagnetic pulse or wave and the at least one transducer that received the mechanical, electrical or electromagnetic pulse or wave, converting, by the at least one receiving transducer, the mechanical, electrical or electromagnetic pulse or wave into a signal;communicating the signal from the at least one receiving transducer to the at leastone integrated circuit physically coupled to the at least one scaffolding that is also physically coupled to the at least one receiving transducer, the signal containing structural or functional information about the assembly of at least two endoluminal prosthetic apparatuses; andtransmitting, by the transmitter, the information about the assembly of at least two endoluminal prosthetic apparatuses to an external device that is external to the apparatus.

48. The method according to claim 47, wherein at least one of the at least two endoluminal prosthetic apparatuses is a stent, a stent graft, a flow diverter, a covered stent or a resorbable scaffold, and wherein generating a mechanical, electrical or electromagnetic pulse or wave by at least one of the at least one transducer includes generating a mechanical, electrical or electromagnetic pulse or wave by at least one of the at least one transducer physically coupled to the scaffolding of the stent, the stent graft, the flow diverter, the covered stent or the resorbable scaffold.

49. The method according to claim 47, wherein transmitting the information comprises transmitting information about at least one of a structural integrity of at least one of the at least two endoluminal prosthetic apparatuses; a mechanical continuity of the at least one of the at least two endoluminal prosthetic apparatuses; a degree of expansion of the scaffolding comprised by at least one of the at least two endoluminal prosthetic apparatuses; an interaction between the at least one of the at least two endoluminal prosthetic apparatuses and the inner wall of the body lumen against which the at least one of the at least two endoluminal prosthetic apparatuses is braced; a relative position of at least two of the at least two endoluminal prosthetic apparatuses; a presence, an absence, a flow rate or a flow velocity of a Type III endoleak.

50. A method of operation of a system comprising an apparatus to gather structural or functional information about at least one endoluminal prosthetic apparatus implanted in a body lumen of a human body or an animal body, using an expandable scaffolding, at least one integrated circuit, at least one transducer, and at least one transmitter, the at least one integrated circuit, at least one transducer, and at least one transmitter physically coupled to the expandable scaffolding, the expandable scaffolding when expanded is at least in part mechanically braced against an inner wall of the body lumen of the human body or the animal body, the method comprising:energizing the at least one integrated circuit to drive the at least one transducer; generating a mechanical, electrical or electromagnetic pulse or wave by at least one of the at least one transducer, the mechanical, electrical or electromagnetic pulse or wave directed toward the at least one endoluminal prosthetic apparatus,receiving, by at least one of the at least one transducer a returned mechanical, electrical or electromagnetic pulse or wave, the mechanical, electrical or electromagnetic pulse or wave representing structural or functional information about at least one of the at least one endoluminal prosthetic apparatus, a mechanical interaction between the endoluminal prosthetic apparatus and the body lumen, a mechanical interaction between the endoluminal prosthetic apparatus and the expandable scaffolding, or a Type III endoleak,converting, by the at least one transducer, the returned mechanical pulse or wave into a signal;communicating the signal from the at least one transducer to the at least one integrated circuit, the signal containing structural or functional information about at least one of the at least one endoluminal prosthetic apparatus, the mechanical interaction between the endoluminal prosthetic apparatus and the body lumen, the mechanical interaction between the endoluminal prosthetic apparatus and the expandable scaffolding, or the Type III endoleak; andtransmitting, by the transmitter, the information about at least one of the at least one endoluminal prosthetic apparatus, the mechanical interaction between the endoluminal prosthetic apparatus and the body lumen, the mechanical interaction between the endoluminal prosthetic apparatus and the expandable scaffolding, or the Type III endoleak, to an external device that is external to the apparatus.

51. The method according to claim 50, wherein the expandable scaffolding of the endoluminal prosthetic apparatus is physically coupled to at least one mechanical or electromagnetic transducer, the method comprising:modifying, by the at least one mechanical or electromagnetic transducer physically coupled to the expandable scaffolding of the endoluminal prosthetic apparatus, the returned mechanical, electrical or electromagnetic pulse or wave through an adjustment of a mechanical impedance or an electromagnetic impedance of the at least one transducer physically coupled to the expandable scaffolding of the endoluminal prosthetic apparatus when the at least one mechanical or electromagnetic transducerphysically coupled to the expandable scaffolding of the endoluminal prosthetic apparatus interacts with the mechanical, electrical or electromagnetic pulse or wave that is generated by the at least one transducer on the apparatus.

52. A method of fabricating a smart implantable device the method comprising: providing a scaffolding, the scaffolding expandable between an unexpanded configuration and an expanded configuration;physically coupling at least one integrated circuit to the scaffolding; and physically coupling a flexible membrane to the scaffolding to expand therewith, the scaffolding and the flexible membrane delimiting a fluidly communicative passageway along at least a portion of the scaffolding at least in the expanded configuration of the scaffolding.

53. The method according to claim 52, wherein the scaffolding comprises at least one strut, and physically coupling the at least one integrated circuit to the scaffolding comprises at least one of:tying at least one thread around at least one of the at least one strut of the scaffolding, ortying at least one thread through an at least one hole in at least one of the at least one strut of the scaffolding.

54. The method according to claim 52, wherein physically coupling the at least one integrated circuit to the scaffolding comprises at least one of:tying at least one thread around at least one of the at least one flexible membrane, ortying at least one thread through an at least one hole in at least one of the at least one flexible membrane.

55. The method according to claim 52, wherein the scaffolding comprises at least one strut, and physically coupling the at least one integrated circuit to the scaffolding comprises at least one of:creating a snap fit between the at least one integrated circuit and at least one of the at least one strut of the scaffolding, orcreating an interference fit between the at least one integrated circuit and at leastone of the at least one strut of the scaffolding.

56. The method according to claim 52, wherein physically coupling the at least one integrated circuit to the scaffolding comprises at least one of:creating a snap fit between the at least one integrated circuit and at least one of the at least one flexible membrane, orcreating an interference fit between the at least one integrated circuit and at least one of the at least one flexible membrane.

57. The method according to claim 52, wherein the scaffolding comprises at least one strut, and physically coupling the at least one integrated circuit to the scaffolding comprises at least partially incorporating the at least one integrated circuit within at least one of the at least one strut of the scaffolding by at least one of:encasing the at least one integrated circuit within a rigid packaging and welding or gluing at least the rigid packaging to the at least one strut of the scaffolding, or sputter coating the at least one integrated circuit with a rigid material.

58. The method according to claim 52, wherein the scaffolding comprises at least one strut, and physically coupling the at least one integrated circuit to the scaffolding comprises:welding or gluing the at least one integrated circuit to at least one of the at least one strut of the scaffolding, orwelding or gluing the at least one integrated circuit to at least one of the at least one flexible membrane.

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