An overview of the microelectromechanical systems employed in cardiology practice: operating principles, diagnostic potential, and future applications

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INTRODUCTION

Since the 1970s, cardiovascular diseases have caused up to 30% of deaths in most developed countries [1]. In the USA, Canada, and a significant portion of European countries, this rate was even higher, reaching ≥40% of total mortality [2]. In Russia, from the mid-1970s to 2014, the proportion of deaths from cardiovascular diseases exceeded 50% of total mortality [3].

Since the beginning of the 21st century, there has been a trend toward a decrease in mortality from cardiovascular diseases due to improved prevention of acute coronary syndrome, better quality of emergency medical care, and an increased number of surgical and X-ray endovascular interventions, which have significantly reduced mortality [4, 5]. Despite these measures, according to the World Health Organization (WHO), there has been a renewed trend toward an increase in mortality since 2015. In 2015, the number of deaths from cardiovascular diseases was 17.7 million and increased to 20.5 million in 2023 [6]. As the number of patients with cardiovascular diseases increases, the burden on the healthcare system grows, leading to additional costs [7]. In 2018, the Russian Federal Project “Combating Cardiovascular Diseases” was initiated as part of the National Project “Healthcare.” According to the Ministry of Health of the Russian Federation, as a result of the project’s implementation in 2018–2022, mortality from cardiovascular diseases decreased by ≥10%, but the rate remains high [8]. In this regard, substantial efforts are directed toward studies aimed at improving monitoring, prevention, and treatment strategies.

Implantable electromechanical devices have become one of the most promising developments. These devices are implanted into the body, do not require prolonged hospitalization, and allow remote monitoring of the patient’s condition and vital parameters [9]. Implantable tonometers and glucose meters can detect changes in blood pressure and glucose levels at an early stage of cardiovascular disease [9]. These devices allow doctors to remotely monitor patients, adjust treatment, and prevent serious complications [9]. In cardiology practice, implantable devices are particularly in demand because the controlled parameters (heart rate, blood pressure, rhythm, glucose level) are of great clinical importance and can help prevent the development of life-threatening complications [10].

The implementation of modern diagnostic devices with wireless signal transmission in medical practice can significantly reduce the burden on healthcare and decrease the number of diagnostic procedures in outpatient and specialized clinics by reading the parameters of interest through an implantable device without invasive methods. Stents with built-in sensors used to restore vascular patency will allow doctors to remotely monitor patients’ condition and make informed decisions about their further management and treatment adjustments [11].

The study aimed to provide an overview of the available research focusing on implantable microelectromechanical systems with remote signal transmission in cardiology practice; to describe in detail their physical operating principles and information transmission mechanisms; and to report the findings from their application in clinical trials.

The review is based on an analysis of scientific publications describing microelectromechanical systems in the medical field from 2004 to 2024 and published in international and national databases, including PubMed, ResearchGate, and eLIBRARY.RU. Data on the physical operating principles of sensors, their applications, remote parameter monitoring capabilities, and results of clinical trials were selected.

The development of implantable sensors for remote monitoring is driven by the desire to more accurately capture critical physiological parameters of the body [12]. Ideally, such devices would help remotely determine indications for treatment and adjust therapy in real time [13].

Microelectromechanical systems (MEMS) are devices in which a mechanical component operates in conjunction with an electrical circuit. They represent a further development of microfabrication, allowing for the registration of physical processes and the creation of devices that include pressure- and flow-rate-sensing elements [14]. Implantable sensors are devices implanted into the body to track various biological parameters or biomarkers. Electronic and optoelectronic sensors have different properties determined by their purpose in studies. These devices are extremely complex, and their functions can range from those that interact with brain tissue through tightly arranged microscopic needles [15] to more complex systems and even therapeutic devices such as retinal implants [16].

The medical field of implantable devices imposes strict requirements on their design. The microfabrication methods developed for creating integrated circuits have been adapted for the production of biomedical devices [12]. This has made it possible to implant miniaturized devices into the human body through continuous advances in microfabrication technologies [17]. For example, a modern pacemaker can be only 2.5 cm in size and weigh <15 g [18]. As MEMS continue to develop, implants will decrease in size, which will also reduce the invasiveness of the procedures required for their implantation [19]. The design of such implantable devices is limited by the specifics of their use, particularly due to complications associated with electrochemical corrosion of materials and immune reactions of the body [20].

The development of MEMS for medical purposes is associated with several challenges at the stages of production and integration. It is primarily necessary to ensure the biocompatibility and inertness of the materials from which these devices are made to avoid immunological reactions or toxic effects on the human body [20, 21]. The limited size of implantable sensors requires the use of materials with high mechanical stability that must also possess sufficient plasticity, such as intravascular sensors integrated into coronary stents [22, 23]. Moreover, each sensor-integrated material has a different electrical response to mechanical loads (e.g., piezoelectric and capacitive materials have different physical characteristics) [21, 23, 24]. In cardiology practice, such devices are particularly in demand due to the high clinical importance of monitoring vital parameters in patients [10].

The primary method of implanting intravascular sensors into the cardiovascular system is endovascular surgery. This is a modern field of medicine that uses access through peripheral vessels. Unlike traditional open surgeries, endovascular procedures are considered less traumatic, allowing patients to regain a higher quality of life more quickly [25]. To date, transcatheter examinations are among the most accurate methods for cardiovascular system assessment [25]. Endovascular surgery includes a wide range of procedures, such as coronary artery stenting, stent graft placement for treating arterial aneurysms and stenoses, as well as diagnostic procedures [26].

Technically, both invasive and noninvasive measurement of intravascular pressure in a specific area of the vessel are possible. Invasive measurement is more accurate but requires endovascular or open surgical procedures, which increases the traumatic nature of the intervention and the risk of tissue and vascular damage and can lead to adverse consequences [22]. Using a pressure-sensing device implanted through transcatheter access enables a more accurate assessment of blood circulation parameters necessary to assess the condition of a particular area of the vessel [22]. Measurement using previously implanted sensors is safer and less dependent on technical factors but can show significant deviations from true values, especially at low blood pressure levels. Implantable intravascular pressure sensors would allow autonomous monitoring of pressure changes in the affected area with high accuracy after a single implantation, eliminating the need for repeated invasive procedures [22].

There are several approaches to classifying these sensors, each allowing consideration of different aspects of their function and operating mechanisms [27]. In this overview, we present a classification based on the physical principle of signal generation, the method of power transmission to the devices, and the physical method of sensor operation.

TYPES AND OPERATING PRINCIPLES OF THE DEVICES

According to the method of signal excitation, wired and wireless methods of energy transfer for signal excitation are distinguished [28]. Wired systems are not suitable for long-term monitoring of specific parameters and are used for measurements at a single point in time, as they require constant energy transfer and the presence of a detection system. Prolonged use of invasive monitoring methods is associated with a high risk of infectious complications and significantly limits the patient’s daily activity. Therefore, most solutions for monitoring physiological parameters use fully implantable devices with wireless data transmission between the sensor and an external monitoring system [29].

According to the mechanism of energy consumption, implantable devices are divided into active, passive, and human-powered types.

Active implantable devices are equipped with a built-in electrical power source [30]. They have a high level of functionality due to electronic circuits and a power supply integrated into a single system. However, the complexity of the design, various layout methods, and insufficient reliability of interaction with other devices are the main disadvantages of active implantable devices. These include electric pacemakers, cardioverter-defibrillators, and blood pressure–sensing devices for monitoring the pulmonary artery, presented by scientists in 2010 [30, 31]. The sensor in such a device is a capacitor, the charging time of which varies depending on the distance between the plates under pressure. The relationship between energy capacity and operating time is shown in Fig. 1a.

 

Fig. 1. Equivalent and functional circuits of sensor-based and biotechnical systems: a, a simplified circuit for capacity vs. time [31]; b, a circuit equivalent to human tissues [32]; c, an electrostatic variable capacity generation system [33]; d, a piezoelectric pressure-sensing device [34]; e, smart-stent signal transmission [35]; and f, an equivalent circuit for transmitting/receiving magnetic resonators [36].

 

For the presented circuit, the charging time is calculated using the following formula:

$t=\frac{V_{MEMS}\cdot C_{MEMS}}{K_p\cdot (W/L)\cdot (1-\lambda \cdot V_{DD}+V_{MEMS}\cdot \lambda )}$

where V_MEMS and C_MEMS are the voltage and capacitance of the MEMS capacitor, respectively; K_p is the process parameter; W is power; L is inductivity; and VDD is the source voltage.

The presented device has all the inherent disadvantages of implantable systems with active elements, including large size and limited service life. This played a significant role in the development of new technologies, emphasizing the use of a MEMS capacitor as a sensor in implantable pressure-sensing devices operating on passive circuits [31].

Implantable passive medical devices do not have a built-in power source for generating diagnostic pulses, which results in a simpler design [37]. For example, by combining an inductor with a capacitive sensor or a surface acoustic wave sensor, implantable passive devices can perform various functions, such as measuring pressure, temperature, and detecting ions [38].

Wireless charging of implantable passive devices is a promising area, as it does not require direct intervention for reuse and significantly increases the service life of such devices [39]. Implantable passive devices use electromagnetic coils instead of batteries to receive energy from an external coil by induction, thereby avoiding the limitations associated with built-in power sources [40].

Until recently, a coil with a diameter of ≤1 cm was required to transfer electromagnetic energy beyond the surface layers of tissue. Research conducted by scientists at Stanford University has led to the development of high-performance wireless power systems that can be integrated into miniaturized medical devices such as stents. The use of magnetic resonance and radio-frequency identification made it possible to overcome these limitations [39].

Some implantable medical devices may be equipped with a rechargeable battery and a receiving coil [41]. The transmitting coil, located outside the body, creates a magnetic field that transmits energy through the skin to the receiver. The alternating current induced in the receiving coil is converted by the rectifier into direct current. However, this method of energy transfer is limited in the depth of signal penetration due to absorption by human tissues and organs (Fig. 2).

 

Fig. 2. Signal penetration depth vs. resonance frequency in the receiver/transmitter.

 

The efficiency of energy transfer and the level of its absorption largely depend on the electrophysical properties of biological tissues [42]. The reflected and transmitted energy of an electromagnetic wave through the interfaces between different tissues is determined by their relative permittivity, conductivity, and frequency [42]. The electrical properties of the tissues under consideration (skin, fat, and muscle) can be represented by an equivalent circuit for modeling (Fig. 1b), where R is resistance, G is conductance, L is inductance, and C is capacitance [32]. The numerical values for the equivalent circuit presented above are shown in Table 1.

 

Table 1. Bioelectrical parameters of human tissues [43]

Bioelectrical parameter	Blood	Muscle	Skin
R, Ohm/m	0	0	0
G, 1/Ohm · m	2,623	4,037	3,533
L, μH/m	1,257	1,257	1,257
C, pF/м	6,270	6,552	3,542

 

It is also necessary to consider the potential risks for people exposed to electromagnetic fields. Recent clinical studies indicate that electromagnetic radiation can have a therapeutic effect in certain cases, but it can also cause changes in the levels of antioxidant markers in the blood, indicating a potential health risk. Further research is needed to study the mechanisms underlying the effects of electromagnetic radiation on the human body and to determine the safe limits of its impact in detail [44].

Human-powered implantable devices use surrounding human tissues as a source of primary energy [45]. These systems capture gravitational, chemical, mechanical, thermal, or electromagnetic energy and convert it into electrical energy [46]. The main issue is that the amount of energy at the output is quite small, but with the advent of ultra–low-power circuits, this method of energy transfer has become an attractive solution for powering implants [47].

In a study conducted by Japanese researchers led by Ryoichi Tashiro, an electrostatic generator with variable capacitance was developed to power an electric pacemaker [33]. The generator is equipped with a variable capacitor that converts mechanical energy into electrical energy through a linear variation of capacitance from C_min to C_max. When a constant voltage V₀ is applied, the generator stores electrostatic energy E_before. When the capacitance changes to C_min under the influence of external forces, the voltage increases:

$V\frac{C_{\max }}{C_{\min }}\cdot V_0$

Then, the generator acquires energy according to the formula below:

$E_{after}=\frac{1}{2}\cdot C_{\min }\cdot V^2=\frac{C_{\max }}{C_{\min }}\cdot \frac{1}{2}\cdot C_{\max }\cdot V_0^2=\frac{C_{\max }}{C_{\min }}\cdot E_{before}$

The generator circuit described above is shown in Fig. 1c and includes an initial charge source (ICS), a variable capacitor (VC) whose capacitance can be adjusted by an external mechanical force, an energy storage capacitor (SC), and two rectifying diodes (D1 and D2). The battery is used only once to supply an electric charge to the capacitor in the microcircuit at the start of power generation. There are two phases in one operating cycle. First, when the AC voltage is low, the microcircuit supplies an electric charge to the VC in a counterclockwise direction (ICS–D1–VC–ICS). Then, as the C1 capacitance gradually decreases under the influence of an external force, the V1 voltage increases. Next, the charge from the VC enters the storage capacitor in a clockwise direction (ICS–VC–D2–SC–ICS). Simultaneously, the electric charge returns and refills the microcircuit. The amount of electric charge in the microcircuit remains constant during one operating cycle. Consequently, the electrical energy in the storage capacitor increases; that is, the mechanical work performed by the external force is converted into electrical energy.

A study of the generator’s operability was conducted on laboratory animals, with the ventricular wall of the heart chosen as the implantation site because its contractions have a large amplitude and occur continuously. In the experiment, an electrostatic generating system with variable capacitance was able to produce 36 µW to power a pacemaker for >2 h [33].

Obviously, additional work is required to achieve either greater power output for devices with long service life or further progress in reducing the energy consumption of miniature devices, which will ensure energy transfer to implantable devices with limited access to energy sources [48].

According to the physical operating principle, sensors are divided into piezoelectric and capacitive types.

The piezoelectric effect occurs due to charge asymmetry within the crystal structure. In a piezoelectric material, ions move more easily along one axis than along others. When exposed to an external force, the ions are displaced in such a way that the opposite sides of the crystal acquire opposite electric charges. When the crystal is connected to a high-impedance circuit, a measurable electric current is generated [49].

Modern piezoelectric sensors are usually equipped with a membrane that transmits liquid pressure to a transducer element, which simultaneously functions as a sensor. In a piezoelectric sensor, the measured value is transmitted directly through solid metal parts to the transducer element. The mechanical stress generated in this way polarizes the element due to the piezoelectric effect, producing a proportional electric charge at the output (Fig. 1d) [50].

Piezoelectric materials such as polyvinylidene and aluminum nitride have a lower Young’s modulus than traditional brittle lead zirconate titanate composites used in ultrasound systems, which simplifies their manufacture and integration into flexible substrates with higher mechanical tensile strength. Small, compact, and thin pressure sensors can be manufactured by placing piezoelectric materials between metal electrodes [51].

The main advantages of the piezoelectric sensor are high sensitivity at low pressure values (<5 kPa), low hysteresis, and vibration resistance, which allows the use of pressure sensors in most industrial applications [52]. A significant disadvantage of this measurement method is circuit complexity and low reliability; therefore, its main field of application is the transcatheter examination of the cardiovascular system [52].

The capacitive pressure-sensing device operates by changing the capacitance that occurs when exposed to a pressure difference, which leads to a change in the distance between the plates and the subsequent conversion of these changes into an electrical signal. This device was first developed in the early 1960s [52]. Capacitive pressure-sensing devices have demonstrated the main advantages of capacitive sensing, namely high pressure sensitivity [53], low power consumption, and low temperature cross-sensitivity [54].

Capacitive pressure-sensing devices usually consist of a dielectric material fixed between conductive electrodes, which provides good sensitivity to high pressures. An additional advantage of this blood pressure measurement method is its simple design and the possibility of wireless power transfer by combining a capacitor with an inductor to form a resonant circuit with a movable upper capacitor plate. In this case, a change in pressure can be detected by a change in the resonant frequency due to a change in capacitance [35]:

$f=\frac{\omega }{2\pi }=\frac{1}{2\pi \sqrt{LC}}$

Due to the ease of wireless connection, this device is widely used in the development of smart-stent and stent-graft systems [56]. Fig. 1e shows the operating principle of the smart stent described above. Using an impedance-measuring device connected to an external antenna, it is possible to measure the resonant frequency characteristics of the sensor, which indirectly indicate intravascular pressure [56].

According to the method of energy transfer to the device through human tissues, ultrasound and electromagnetic methods are distinguished.

Ultrasound energy transfer

The ultrasound energy transfer method is implemented in the PAPIRUS II system (Boston Scientific, Marlborough, USA). The sensor is designed to detect pressure in the aneurysmal area of the aorta, detect endoleaks, and monitor pressure after the placement of a stent graft. This implantable device is also used to measure pressure in the pulmonary artery in patients with chronic heart failure [57]. PAPIRUS II consists of an implant and an external unit. The implant contains a pressure sensor, a piezoelectric transducer, a control circuit, and a battery (Fig. 3).

 

Fig. 3. Pressure-sensing device for monitoring abdominal aortic aneurysms [58].

 

This method of energy transfer makes it possible to dispense with built-in power sources, extending the service life of the implant [58]. The activated device measures pressure using the capacitive method. Within 10 s, the full waveform of pressure fluctuations is recorded, allowing analysis of their dynamics [58]. The transmitted analog signal is susceptible to electromagnetic interference, as any changes in the surrounding electric field can induce additional noise and distortion [59, 60].

German scientists were able to overcome the issue of analog signal susceptibility to electromagnetic interference by using digital signal transmission instead of analog [58]. The sensor, designed to detect pressure in the aneurysmal sac, can detect endoleaks and monitor pressure after the placement of a stent graft. The developed pressure-sensing device is designed as a capsule that contains the necessary passive components (capacitors, receiving coil, and Zener diodes) as well as a digital data processing unit [58].

Electromagnetic energy transfer

Wireless energy transfer through the patient’s tissues is possible using electromagnetic fields. One example of such technology is the Leviticus Cardio circulatory support system, developed in Israel [36]. Its operating principle is based on Coplanar Energy Transfer technology, which enables energy transfer between two magnetic coils: one implanted in the pleural cavity and the other located on the surface of the chest. Energy transfer is achieved through electromagnetic induction (Fig. 1f) [36]. The circulatory device can operate autonomously for up to 6–8 h, significantly improving patients’ quality of life. An artificial heart ventricle with a rotary or centrifugal pump to support blood circulation is used in patients with heart failure until heart transplantation [36].

Energy transfer in this system is achieved through two resonators that interact via electromagnetic fields. The power amplifier supplies an alternating current signal to a transmitting resonator consisting of a single-turn excitation circuit and a multi-turn coil. The current passing through the transmitting coil creates a magnetic field that induces an electric current in the second resonator, which is implanted in the pleural cavity. This resonator also includes a multi-turn coil and a single-turn receiving circuit. The received AC signal is rectified and converted into a direct voltage, which is then fed through the controller to the pump of the artificial heart ventricle.

Energy transfer depends on the distance between the transmitting and receiving resonators, and their coupling is inversely proportional to this distance. The automatic tuning system dynamically adjusts the operating frequency, adapting to changes in the position of the resonators, which allows the system to maintain maximum energy transfer efficiency. For resonators of the same size, the effective energy transfer zone covers a distance of up to two coil radii. The transmission range can be increased by adding an intermediate coil between the transmitting and receiving resonators or by using multiple relay resonators. However, each additional element slightly reduces the overall efficiency of the system due to parasitic losses [55].

The clinical application of the Leviticus Cardio system was described in two patients aged 51 and 24 years with end-stage heart failure, who were the first to be implanted with this system. The results of early monitoring confirmed the effectiveness of the system: the battery charge was sufficient for 8.5 h of rotary pump operation. During the study, there were no device malfunctions or infectious complications associated with its implantation [61].

EXAMPLES OF IMPLANTABLE MEDICAL DEVICES

Coronary stents

Coronary stents are hollow tubular structures with a metal frame used to restore the patency of arteries narrowed as a result of atherosclerosis [62]. In Russia, the annual number of endovascular interventions using coronary stents is increasing and amounts to approximately 27.5 per 100,000 population [63]. Peripheral arteries are used for endovascular access, and selective angiography of the coronary bed is performed to detect stenoses that restrict blood flow to the myocardium [11]. After the stenting procedure, atherosclerotic changes can lead to restenosis or thickening of the inner vessel wall, thrombosis, and proliferation of smooth muscle cells [11]. Despite the use of drug-eluting stents that contain drugs to suppress endothelial proliferation, stenosis can occur in up to 15% of cases [64, 65].

To detect thrombosis and monitor coronary artery patency after stenting, stents with an integrated pressure sensor and a communication system (smart stents) based on micro- or nanoelectromechanical systems have been developed. These devices have great potential for providing diagnostic feedback for the early detection of adverse thrombotic events [62]. This technology can provide valuable information about the condition of the coronary bed and is crucial for timely intervention and increasing the likelihood of a successful revascularization procedure [66].

The prospects for the development of stents with a pressure monitoring system were discussed by Vishnu and Manivasagam. The main functions of a smart stent should include accurate measurement of pressure, blood flow velocity, and endothelialization control. For example, a stent model developed in 2010 detects the growth of endothelial cells by changes in surface charge, which lead to changes in the resonance and frequency of the device, indicating the process of endothelialization.

A new paradigm in smart stent research is the use of biodegradable materials for their framework. In particular, polymer compounds based on lactic acid, such as poly-L-lactide, poly-D-lactide, and polycaprolactone, are used with integrated pressure sensor systems. These pressure-sensing devices are capable of measuring pressures up to 230 mmHg [11].

A serious complication in the implantation of drug-eluting coronary stents is late thrombosis, which occurs due to unprotected stent elements that are not covered with endothelial cells during the healing process [11]. Long-term monitoring of the endothelialization process can help in more carefully selecting an antiplatelet therapy. Research in this area mostly remains at the modeling and experimental development stage.

In a 2010 study, a team of scientists led by Chow introduced a fully wireless implantable pressure monitor integrated into a medical stent. The device transmitted data with a resolution of 0.5 mmHg within a range of 0–50 mmHg, receiving power externally and enabling data transmission at a distance of up to 10 cm [31]. Based on these developments, an intelligent telemetry stent for wireless monitoring of intravascular pressure was introduced in 2014 [31]. A 2023 review highlighted the potential of such devices for continuous patient monitoring as well as unresolved issues hindering their clinical implementation—biocompatibility, reliability of data transmission, and standardization of protocols [31].

Despite the progress, the widespread use of smart stents requires additional testing to confirm their safety and effectiveness. Current studies are aimed at solving these problems to introduce innovative devices into clinical practice [11].

Stent grafts

Stent grafts are an advanced method of providing highly specialized care for aortic aneurysms. Acute dissection of the thoracic aorta is a medical emergency. Type A aortic dissection is considered the most severe form due to aorto-associated complications, with mortality reaching 70%–80% [64]. In such cases, pharmacotherapy is associated with a mortality rate of 50%–70% during the first month and is considered ineffective [67].

Endovascular plasty of an abdominal aortic aneurysm was first performed by Loschi et al. in 1991. Modern monitoring protocols following the placement of an endovascular stent graft for the correction of aortic aneurysms are based primarily on expensive and time-consuming imaging methods aimed at detecting graft migration and endothelial ruptures in aneurysmally altered areas of the aorta [68].

A hybrid stent graft is a structure consisting of a metal frame covered with fabric. After placement in the aortic lumen, the device functions as a vascular wall replacement. However, the use of this method can be accompanied by complications, the most common of which is endoleak—the leakage of blood into the aneurysmal sac after endovascular intervention [69]. Types I, II, and III endoleaks pose the greatest danger, as they are associated with increased pressure in the aneurysmal sac, which can lead to its progressive enlargement, aneurysm rupture, and, consequently, death due to massive bleeding.

To monitor pressure in the aneurysmal sac, an implantable telemetric pressure sensor, the EndoSure Sensor, was developed. Integrated into the implant, this sensor helps detect endoleaks and reduces the need for additional examinations using contrast agents. The device consists of electronic components surrounded by nitinol threads arranged in a basket shape, with the active element located at the center. The sensor has no battery and draws energy from an external source. In vivo tests have shown that the sensor remains functional for several years, demonstrating high stability [57].

Ohki et al. presented the results of a clinical trial of the EndoSure Sensor [70]. The study included 90 patients from 12 medical centers, with a mean age of 72.3 years. The mean aneurysm diameter at the time of examination was 5.48 ± 1.07 cm. The average procedure time was 205 ± 87 min, and the mean blood loss was 471 ± 387 mL. After endovascular aneurysm repair, blood pressure in the aneurysmal sac decreased from 59.34 ± 17.8 mmHg to 27.5 ± 18.8 mmHg. The sensor was calibrated using direct pressure gauge data during implantation and upon removal of the guidewire. To assess the device’s safety and the stability of its readings, a 30-day patient follow-up was conducted. During this time, no signs of endoleak were detected, and the pressure in the aneurysmal sac remained stable. Five instances of discrepancy between the pressure measured by the sensor and that recorded during the endovascular procedure were noted; however, these did not affect the outcomes. Later, after stent graft placement, the pressure in the early postoperative period also decreased. No adverse events related to the use of the pressure-sensing device were reported [71]. During the early postoperative follow-up period, two deaths were recorded, but both were associated with the severe course of the underlying disease and comorbid conditions rather than the implantation procedure or sensor operation [5].

Stent grafts, as well as stents with an integrated sensor and communication system (smart stent grafts) based on micro- or nanoelectromechanical systems, have great potential for providing diagnostic feedback for endoleak detection [71].

The main disadvantage of capacitive pressure sensors in smart stents and stent grafts is the lack of proven protection mechanisms against endothelial buildup, as a result of which the mechanical component ceases to function [72].

Pulmonary Artery Pressure-sensing device

CardioMEMS is an implantable pressure-sensing device used to measure pressure in the branches of the pulmonary artery for the management of pulmonary arterial hypertension. The device consists of a liquid crystal reservoir (inductive-capacitive) and operates on the principle described above [58].

Using a portable electronic device and a special sensor with an antenna at home, the collected data are converted into pressure readings and transmitted to a secure server for further processing. The data-reading process is painless: the pressure-sensing device with the antenna is applied to the body at the intended location of the implant, causing no significant sensations. The electronic unit transmits the pulmonary artery pressure measurements to the physician daily, allowing treatment for heart failure to be adjusted before the onset of clinical signs of congestion. This, in turn, helps reduce the number of hospitalizations and deaths [58].

CardioMEMS has demonstrated a significant decrease in the number of hospitalizations among patients with NYHA class III heart failure [73]. Since 2014, CardioMEMS has been officially approved for monitoring patients with heart failure. In a study by Sarsam et al., successful early detection of infective endocarditis with aortic valve damage using CardioMEMS was reported, which was associated with increased pressure in the pulmonary artery [8].

Additionally, monitoring pressure in the pulmonary artery using such technologies can be useful for optimizing the treatment of patients with pulmonary hypertension and for early detection of complications following implantation of an artificial heart ventricle. Such an approach expands the possibilities for comprehensive management of critically ill patients and improves disease prognosis [58, 74]. In the Russian Federation, similar implantable sensors have not yet been used in clinical practice, and the field of remote monitoring of patients with cardiovascular diseases using other technologies is still developing. This aligns with the global trend toward the digitalization and personalization of cardiac care.

In 2018, Feldman et al. studied an implantable pressure-sensing device in the branches of the pulmonary artery as a tool for determining the optimal implantation time and optimizing the operation of an artificial heart ventricle [58, 74]. The device was implanted in 27 patients for 18 months, during which systemic and pulmonary pressure parameters as well as blood chemistry parameters were evaluated. All patients received similar pharmacotherapy. Implantation of the artificial heart ventricle was performed earlier than planned, based on the increased pulmonary pressure recorded by the device [75]. Similar results were obtained in studies by Veenis et al., which showed that using a pressure-sensing device in the branches of the pulmonary artery improves patient monitoring outcomes in individuals with end-stage heart failure who subsequently required heart transplantation [76].

The incidence of complications associated with implantable pressure-sensing devices in the branches of the pulmonary artery is extremely low, accounting for approximately 1% of all implantations. In most cases, complications were limited to bleeding at the puncture site after the endovascular procedure [76]. These results demonstrate the importance of implantable pressure-sensing devices in clinical practice for pressure monitoring and therapy management in patients with heart failure.

CONCLUSION

The development of microelectronics makes it possible to create implantable microcircuits for tracking essential parameters. These devices are characterized by their small size, ability to provide long-term monitoring of the patient’s condition, reduced invasiveness of implantation procedures, and a personalized approach to treatment. Modern advances in microelectromechanical systems are opening new avenues in cardiology by creating more sophisticated systems for monitoring physiological parameters of the body. In cardiovascular diseases, parameters such as blood pressure and flow rate in the affected area are particularly important. The implementation of implantable microcircuits in clinical practice will help reduce the burden on healthcare, decrease the number of hospitalizations, improve the quality of monitoring, and enable the detection of life-threatening conditions. Research on MEMS is expanding the scope of implantable devices through high-tech developments that are modernizing healthcare. Remote monitoring systems address several challenges: they reduce the number of invasive procedures, allow sensors to be installed once in the desired area, support decision-making regarding repeated procedures and treatment adjustments, and provide continuous remote monitoring of physiological parameters.

ADDITIONAL INFORMATION

Author contributions: T.A.A.: conceptualization, data curation, writing—review & editing; T.N.M.: conceptualization, visualization, writing—original draft; B.E.S.: writing—review & editing, general supervision. All the authors approved the version of the manuscript to be published and agreed to be accountable for all aspects of this work, ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Funding sources: Ministry of Science and Higher Education of the Russian Federation (theme No. FEWM-2024-0008).

Disclosure of interests: The authors have no relationships, activities, or interests for the last three years related to for-profit or not-for-profit third parties whose interests may be affected by the content of the article.

Statement of originality: This work does not contain any material adopted or reprinted from other sources without proper referencing. This is an overview article that contains bibliographic references to all sources of information that were used and reviewed.

Data availability statement: The authors provide limited access to the data (upon request, post-embargo). The data used in this study can be made available upon reasonable request. The request must include a detailed description of the intended use of the data. Contact person for access inquiries: A.A. Talovskaya, email: alenaatalovskaia@tusurru. The extent of data available: search results in bibliographic databases.

Generative AI: No generative artificial intelligence technologies were used to prepare this article.

Provenance and peer review: This paper was submitted unsolicited and reviewed following the fast-track procedure. The peer review process involved two external reviewers, a member of the editorial board, and the in-house scientific editor.

About the authors

Alena A. Talovskaia

Tomsk State University of Control Systems and Radioelectronics

Author for correspondence.
Email: alena.a.talovskaia@tusur.ru
ORCID iD: 0009-0001-6796-1135
SPIN-code: 1488-3280

junior research associate, Lab. of Microsystems Technology, engineer Scientific and Educational Centre ‘Nanotechnologies’

Russian Federation, Tomsk

Evgeny S. Barbin

Tomsk State University of Control Systems and Radioelectronics

Email: evgeniisbarbin@tusur.ru
ORCID iD: 0000-0001-5904-0216
SPIN-code: 5976-5975

Cand. Sci. (Engineering), Head, Microsystems Technology Laboratory, senior research associate, Lab. of Microelectronic and Photonic Systems of the MES Research Institute and the Laboratory of Microwave Microelectronics of the MES Research Institute, Assistant Professor, Advanced engineering schools “Electronic Instrumentation and Communication Systems named after AV Kobzev”

Russian Federation, Tomsk

Nikita M. Troshkinev

Tomsk State University of Control Systems and Radioelectronics; Tomsk National Research Medical Center

Email: nikitamtroshkinev@tusur.ru
ORCID iD: 0000-0001-7627-7303
SPIN-code: 4983-5122

MD, Cand. Sci. (Medicine), Doctor, and Cardiovascular Surgeon, Cardiac Surgery Depart. № 2, research associate, Tomsk NRMC, Cardiology Research Institute, and of the Microsystems Technology Laboratory

Russian Federation, Tomsk; Tomsk

References

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