Cardiovascular Implantable Devices Research Articles

Review of Systemic Mock Circulation Loops for Evaluation of Implantable Cardiovascular Devices and Biological Tissues.

On needs-based ex vivo monitoring of implantable devices or tissues/organs in cardiovascular simulators provides new insights and paves new paths for device prototypes. The insights gained could not only support the needs of patients, but also inform engineers, scientists and clinicians about undiscovered aspects of diseases (during routine monitoring). We analyze seminal and current work and highlight a variety of opportunities for developing preclinical tools that would improve strategies for future implantable devices. Holistically, mock circulation loop studies can bridge the gap between in vivo and in vitro approaches, as well as clinical and laboratory settings, in a mutually beneficial manner.

Pharmacologic targeting of coagulation factors XII and XI by monoclonal antibodies reduces thrombosis in nitinol stents under flow

BackgroundCardiovascular implantable devices, such as vascular stents, are critical for the treatment of cardiovascular diseases. However, their success is dependent on robust and often long-term antithrombotic therapies. Yet, the current standard-of-care therapies often pose significant bleeding risks to patients. Coagulation factor (F)XI and FXII have emerged as potentially safe and efficacious targets to safely reduce pathologic thrombin generation in medical devices. ObjectivesTo study the efficacy of monoclonal antibody–targeting FXII and FXI of the contact pathway in preventing vascular device–related thrombosis. MethodsThe effects of inhibition of FXII and FXI using function-blocking monoclonal antibodies were examined in a nonhuman primate model of nitinol stent–related thrombosis under arterial and venous flow conditions. ResultsWe found that function-blocking antibodies of FXII and FXI reduced markers of stent-induced thrombosis in vitro and ex vivo. However, FXI inhibition resulted in more effective mitigation of thrombosis markers under varied flow conditions. ConclusionThis work provides further support for the translation of contact pathway of coagulation inhibitors for their adjunctive clinical use with cardiovascular devices.

Focus on interventional cardiology: the need for quality and transparency of evidence for implantable cardiovascular medical devices.

Focus on interventional cardiology: the need for quality and transparency of evidence for implantable cardiovascular medical devices.

Passivation protein-adhesion platform promoting stent reendothelialization using two-electron-assisted oxidation of polyphenols

Superhydrophilic surfaces play an important role in nature. Inspired by this, scientists have designed various superhydrophilic materials that are widely used in the field of biomaterials, such as PEG molecular brushes and zwitterionic materials. However, superhydrophilic coatings with only anti-fouling properties do not satisfy the requirements for rapid reendothelialization of cardiovascular stent surfaces. Herein, a novel polyphenol superhydrophilic surface with passivated protein-adsorption properties was developed using two-electron oxidation of dopamine and polyphenols. This coating has a multiscale effects: 1) macroscopically: anti-fouling properties of superhydrophilic; 2) microscopically: protein adhesion properties of active groups (quinone-, amino-, hydroxyphenyl groups and aromatic ring). Polyphenols not only enhance the ability of coating to passivate protein-adsorption, but also make the coating have polyphenol-related biological functions. Therefore, the polyphenol and passivated protein-adsorption platform together maintain the stability of the scaffold microenvironment. This, in turn, provides favorable conditions for the growth of endothelial cells on the scaffold surface. In vivo implantation of the coated stents into the abdominal aorta resulted in uniform and dense endothelial cells covering the surface of the neointima. Moreover, new endothelial cells secreted large amounts of functional endothelial nitric oxide synthase like healthy endothelial cells. These results indicate that the polyphenol superhydrophilic coating potentially resists intra-stent restenosis and promotes surface reendothelialization. Hence, polyphenol superhydrophilic coatings with passivated protein-adsorption properties constructed by two-electron-assisted oxidation are a highly effective and versatile surface-modification strategy for implantable cardiovascular devices.

Generation of synthetic aortic valve stenosis geometries for in silico trials.

In silico trials are a promising way to increase the efficiency of the development, and the time to market of cardiovascular implantable devices. The development of transcatheter aortic valve implantation (TAVI) devices, could benefit from in silico trials to overcome frequently occurring complications such as paravalvular leakage and conduction problems. To be able to perform in silico TAVI trials virtual cohorts of TAVI patients are required. In a virtual cohort, individual patients are represented by computer models that usually require patient-specific aortic valve geometries. This study aimed to develop a virtual cohort generator that generates anatomically plausible, synthetic aortic valve stenosis geometries for in silico TAVI trials and allows for the selection of specific anatomical features that influence the occurrence of complications. To build the generator, a combination of non-parametrical statistical shape modeling and sampling from a copula distribution was used. The developed virtual cohort generator successfully generated synthetic aortic valve stenosis geometries that are comparable with a real cohort, and therefore, are considered as being anatomically plausible. Furthermore, we were able to select specific anatomical features with a sensitivity of around 90%. The virtual cohort generator has the potential to be used by TAVI manufacturers to test their devices. Future work will involve including calcifications to the synthetic geometries, and applying high-fidelity fluid-structure-interaction models to perform in silico trials.

Contemporary Features and Management of Endocarditis.

Infective endocarditis is a rare but devastating disease. Morbidity and mortality rates have failed to improve despite new technological advances. The disease has evolved over time with new significant populations at risk-most notably those with prosthetic valves or implantable cardiovascular devices. These devices pose new challenges for achieving a timely and accurate diagnosis of infection. While the modified Duke criteria is accepted as the gold standard for diagnosing native valve endocarditis, it has been shown to have significantly inferior sensitivity when it comes to identifying infections related to right-heart endocarditis, prosthetic valves, and indwelling cardiac devices. Additionally, prosthetic valves and cardiovascular implantable electronic devices can exhibit shadowing and artifact, rendering transthoracic echocardiography and transesophageal echocardiography results inconclusive or even normal. Having a keen awareness of the varying clinical presentations, as well as emerging valvular imaging modalities such as F-fluorodeoxyglucose cardiac positron-emission tomography plus computed tomography, promises to improve the evaluation and diagnosis of infective endocarditis. However, indications for appropriate use of these studies and guidance on modern clinical management are still needed.

Polyester urethane urea (PEUU) functionalization for enhanced anti-thrombotic performance: advancing regenerative cardiovascular devices through innovative surface modifications.

Introduction: Thrombogenesis, a major cause of implantable cardiovascular device failure, can be addressed through the use of biodegradable polymers modified with anticoagulating moieties. This study introduces a novel polyester urethane urea (PEUU) functionalized with various anti-platelet deposition molecules for enhanced antiplatelet performance in regenerative cardiovascular devices. Methods: PEUU, synthesized from poly-caprolactone, 1,4-diisocyanatobutane, and putrescine, was chemically oxidized to introduce carboxyl groups, creating PEUU-COOH. This polymer was functionalized in situ with polyethyleneimine, 4-arm polyethylene glycol, seleno-L-cystine, heparin sodium, and fondaparinux. Functionalization was confirmed using Fourier-transformed infrared spectroscopy and X-ray photoelectron spectroscopy. Bio-compatibility and hemocompatibility were validated through metabolic activity and hemolysis assays. The anti-thrombotic activity was assessed using platelet aggregation, lactate dehydrogenase activation assays, and scanning electron microscopy surface imaging. The whole-blood clotting time quantification assay was employed to evaluate anticoagulation properties. Results: Results demonstrated high biocompatibility and hemocompatibility, with the most potent anti-thrombotic activity observed on pegylated surfaces. However, seleno-L-cystine and fondaparinux exhibited no anti-platelet activity. Discussion: The findings highlight the importance of balancing various factors and addressing challenges associated with different approaches when developing innovative surface modifications for cardiovascular devices.

Quality and transparency of evidence for implantable cardiovascular medical devices assessed by the CORE-MD consortium.

The European Union Medical Device Regulation 2017/745 challenges key stakeholders to follow transparent and rigorous approaches to the clinical evaluation of medical devices. The purpose of this study is a systematic evaluation of published clinical evidence underlying selected high-risk cardiovascular medical devices before and after market access in the European Union (CE-marking) between 2000 and 2021. Pre-specified strategies were applied to identify published studies of prospective design evaluating 71 high-risk cardiovascular devices in seven different classes (bioresorbable coronary scaffolds, left atrial appendage occlusion devices, transcatheter aortic valve implantation systems, transcatheter mitral valve repair/replacement systems, surgical aortic and mitral heart valves, leadless pacemakers, subcutaneous implantable cardioverter-defibrillator). The search time span covered 20 years (2000-21). Details of study design, patient population, intervention(s), and primary outcome(s) were summarized and assessed with respect to timing of the corresponding CE-mark approval. At least one prospective clinical trial was identified for 70% (50/71) of the pre-specified devices. Overall, 473 reports of 308 prospectively designed studies (enrolling 97 886 individuals) were deemed eligible, including 81% (251/308) prospective non-randomized clinical trials (66 186 individuals) and 19% (57/308) randomized clinical trials (31 700 individuals). Pre-registration of the study protocol was available in 49% (150/308) studies, and 16% (48/308) had a peer-reviewed publicly available protocol. Device-related adverse events were evaluated in 82% (253/308) of studies. An outcome adjudication process was reported in 39% (120/308) of the studies. Sample size was larger for randomized in comparison to non-randomized trials (median of 304 vs. 100 individuals, P < .001). No randomized clinical trial published before CE-mark approval for any of the devices was identified. Non-randomized clinical trials were predominantly published after the corresponding CE-mark approval of the device under evaluation (89%, 224/251). Sample sizes were smaller for studies published before (median of 31 individuals) than after (median of 135 individuals) CE-mark approval (P < .001). Clinical trials with larger sample sizes (>50 individuals) and those with longer recruitment periods were more likely to be published after CE-mark approval, and were more frequent during the period 2016-21. The quantity and quality of publicly available data from prospective clinical investigations across selected categories of cardiovascular devices, before and after CE approval during the period 2000-21, were deemed insufficient. The majority of studies was non-randomized, with increased risk of bias, and performed in small populations without provision of power calculations, and none of the reviewed devices had randomized trial results published prior to CE-mark certification.

In vitro evaluation of blood plasma coagulation responses to four medical-grade polyurethane polymers.

Segmented polyurethane (PU) block copolymers are widely used in implantable cardiovascular medical devices due to their good biocompatibility and excellent mechanical properties. More specifically, PU Biospan MS/0.4 was used in ventricular assist devices over the past decades. However, this product is being discontinued and it has become necessary to find an alternative PU biomaterial for application in cardiovascular devices. One important criterion for assessing cardiac biomaterials is blood compatibility. In this study, we characterized the surface properties of four medical-grade PU biomaterials: Biospan MS/0.4, BioSpan S, BioSpan 2F, and CarboSil 20 80A, including surface chemistry, topography, microphase separation structure and wettability, and then measured the blood plasma coagulation responses using bovine and human blood plasma. Results showed that BioSpan 2F contains high amounts of fluorine and has the lowest surface free energy while the other materials have surfaces with silicone present. An in vitro coagulation assay shows that these materials demonstrated improved blood coagulation responses compared to the polystyrene control and there were no significant differences in coagulation time among all PU biomaterials. The chromogenic assay showed all PU materials led to low FXII contact activation, and there were no significant differences in FXII contact activation, consistent with plasma coagulation responses.

BIO26: Engineering Anti-platelet polymers for regenerative cardiovascular applications

Thrombogenesis is the main failure cause of implantable cardiovascular devices. Thrombus formation not only occludes devices but exacerbates immune responses responsible for foreign body reaction. Biodegradable polymers modified with anticoagulating moieties represent a strategy to overcome these limitations. Herein, we propose the use of a novel polyester urethane urea (PEUU) with pendant carboxyl groups for functionalization with different anti-platelet deposition molecules. PEUU was synthesized from PCL (Polycaprolactone), 1,4-diisocyanatobutane and putrescine, and then chemically oxidized to introduce carboxyl groups in the polymer backbone (PEUU-COOH). PEUU-COOH was functionalized in-situ with Polyethyleneimine mW 400 (PEI), 4 arm Polyethylene Glycol (PEG-4-Arm-NH2), seleno-L-cystine, heparin sodium and fondaporinux as anti-platelet deposition molecules. After solvent casting, functionalization was confirmed via Fourier-transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Metabolic activity (MTT) and hemolysis assays were performed to validate biocompatibility. Anti-platelet activity of PRP exposed films was examined via a platelet aggregation assay, through an activation assay via lactate dehydrogenase (LDH), and by surface imaging with scanning electron microscopy (SEM). Whole-blood clotting time quantification assay was carried out to evaluate anticogulating properties. Upon oxidation, PEUU exhibited COOH pendant groups that were successfully employed to conjugate the anti-platelet molecules, obtaining homogeneous films. Overall cytotoxicity was below 20% and the hemolysis was below 5%, suggesting high biocompatibility and hemocompatibility. The most potent anticoagulant activity was obtained for heparin-functionalized materials followed by PEG-4-Arm-NH2 and PEI. Surprisingly, Seleno-L-cystine and Fondaporinux showed no anti-platelet activity. Results indicate that the polymers introduced here are a promising strategy to avoid thrombogenesis in vascular grafts.

925 THE TWIDDLER'S SYNDROME: A CASE REPORT

Abstract Introduction The Twiddler's syndrome is a rare condition of malfunctioning of a cardiovascular implantable elettronic device (CIED) due to the rotation of the device around its own long axis within its pocket. This brings to the leads wrapping around the device case and consequently dislocating, resulting in a deficit in sensing and pacing. Case Report We present the case of an 82-year-old woman, affect by atrial and conduction tissue disease for which was implanted a dual-chamber PaceMaker (PM). She arrived at the emergency department for asthenia and a traumatic syncopal episode, preceded by intense general malaise, nausea and vomiting. At EKG findings of electroinduced atrial rhythm, electroinduced ventricular rhythm with loss of capture and emergence of spontaneous rhythm, with subsequent resumption of capture. At device telemetry check, rise of ventricular and atrial pacing thresholds together with sporadic ventricular capture losses. Chest×Ray showed entanglement of leads around the PM case and retraction of the ventricular catheter. Therefore, the patient was admitted to the cardiology department, and the surgical pocket was revised with case extraction and leads debridement with subsequent optimization of their position. The next day, following device telemetry check, which showed good electrical parameters, and the follow-up chest X-Ray, which was normal, the patient was discharged. Conclusion All physicians, particularly cardiologists, must pay close attention to the evaluation of patients with CIEDs. First of all, meticulous analysis of the EKG must be performed, which is capable of showing loss of capture and abnormal QRS morphologies due to cardiac pacing at abnormal locations. In addition, it is necessary to perform the telemetry check of the device, infact findings of sensing deficits and/or elevation of pacing thresholds indicate device malfunctioning, which is not necessarily due to leads injuries. Displacement of the leads can be easily detected with a chest X-ray, always remembering to rule out the presence of Twiddler syndrome, however rare it may be.

A Survey of Antibiotic Use During Insertion of Cardiovascular Implantable Devices Among United States Implanters.

Antibiotic use for cardiovascular implantable devices (CIED) prophylaxis is well-accepted despite a paucity of data. Pre-procedural prophylaxis lowers the rate of CIED infections; however, data is lacking for intra- or post-procedural antibiotic use. Antibiotic-eluting envelopes (ENVELOPE) [TYRX®TM] have been shown to reduce post-procedural infections. Understanding implanter practices may provide insight as to the need for antibiotic stewardship. The purpose of this survey was to assess the practices of implanters nationally. A survey was completed by 150 implanters across the US. Participants were board certificated, implanters of CIEDs, with varying experience (1-25years), in various hospital settings. Of the respondents, 97% reported routine use of systemic antibiotics pre-operatively. About two-thirds of implanters continue systemic antibiotics post-operatively, with half continuing antibiotics for >24h; 83% of implanters add antibiotic to saline for the purpose of irrigating the wound; 55% routinely use ENVELOPE on approximately 38% of patients. Common reasons cited for ENVELOPE use were infection concerns, significant risk factors, prior device infection, and immunosuppressed status. Two-thirds of respondents use systemic antibiotics during generator changes, with >50% continuing antibiotics for >24h. This study suggests wide variations in practice among implanters. Additional attention to existing guidelines and evidence regarding appropriate use of ENVELOPE is still needed.

Interference thresholds for active implantable cardiovascular devices in occupational low-frequency electric and magnetic fields: a numerical and in vitro study

In light of concerns regarding the occupational safety and health of workers wearing active implantable medical devices (AIMDs), this study aims to investigate the potential risks of electromagnetic interference (EMI) between AIMDs and low-frequency 50/60 Hz electromagnetic fields (EMFs) in the workplace. A total of 58 AIMDs, consisting of pacemakers (PMs) and implantable cardiac defibrillators (ICDs) of different brands, models, and configurations were tested to determine the immunity thresholds for high-voltage electric fields (EFs) and magnetic fields (MFs) at 50/60 Hz. The EFs and MFs at the levels in workplaces are reproduced by setups using Helmholtz coils and aluminum plates, respectively, to ensure that the EM/MF exposures are controllable and reproducible. The EMI thresholds were recorded by observing the occurrences of PM or ICD dysfunctions. In addition, numerical studies on anatomical models were carried out using CST® software. The results indicate that the recorded thresholds all exceed the EF and MF public exposure limits given in the ICNIRP 2010 guidelines. No dysfunction was observed among four ICDs tested under MF exposure up to 2750 µT at 50 Hz and 2480 µT at 60 Hz. However, among the 43 PMs and 11 ICDs tested under EF exposures, potential hazards may occur below the occupational exposure level proposed in the ICNIRP guidelines.

Three simple but interesting transthoracic echocardiographic road maps for proximal superior vena cava visualisation in healthy young adults.

BackgroundAlthough much is known about the technical aspects of inferior vena cava visualization, it is much less about its counterpart: the superior vena cava (SVC). The aims of this study therefore, were to describe in detail the different possible two dimensional echocardiographic SVC visualization techniques in healthy young adults and to provide a series of values for its dimensions and Doppler signals.MethodsThe proximal SVC visualization through the three transthoracic windows was initially established in several adult patients, with or without cardiovascular implantable devices. Subsequently a group of 70 completely healthy adults (35 males and 35 females) were studied to determine the values of SVC dimensions and its pulse Doppler signal characteristics. The visualization windows included: a) Modified apical 5-champber view, b) Modified parasternal short axis view of great vessels and c) Modified subcostal view. The SVC dimensions were measured 3–5 cm above the RA-SVC junction at the end of both hold cardiac and respiratory cycles (systole, diastole and inspiration/expiration, respectively). The peak pulse Doppler velocities were only measured at the end-held expiration.ResultsThe largest end systolic proximal SVC dimensions at the end of the expiration and inspiration ranged from 8 to 14.0 mm (11 ± 2 mm) and 8.0–14.0 mm (11 ± 2 mm) respectively, and the highest S wave velocity ranged from 0.5 to 0.7 m/s (0.6 ± 0.0 m/s).ConclusionThis study has provided a detailed technical description for transthoracic proximal SVC visualization in a group of 70 healthy adults and has furnished sets of values for its dimensions and Doppler signal parameters.

Evolution of antibacterial and antibiofouling properties of sharkskin-patterned surfaces

Sharks possess numerous biological features such as highly developed senses and an efficient liver that have stunned researchers over the past few decades. Aside from these, sharks are well known for the ability of their skin to reduce drag force and prevent adhesion of microorganisms such as bacteria. Recently, investigating the antibiofouling properties of sharkskin and particularly the mechanism of antibacterial activities has been trending, and ongoing research studies are conducted to understand the extent of the antibiofouling and identify the possible underlying mechanisms. Hence, in this review, the authors take a look at sharkskin morphology and discoveries thus far regarding its unique attributes and their underlying mechanisms along with possible applications such as catheters, implantable cardiovascular devices and medical devices. The focus of this review is the antibiofouling properties of sharkskin-patterned surfaces prepared through biomimicked and bioinspired approaches in healthcare applications.

Strategies for Improving Endothelial Cell Adhesion to Blood-Contacting Medical Devices.

The endothelium is a critical mediator of homeostasis on blood-contacting surfaces in the body, serving as a selective barrier to regulate processes such as clotting, immune cell adhesion, and cellular response to fluid shear stress. Implantable cardiovascular devices, including stents, vascular grafts, heart valves, and left ventricular assist devices, are in direct contact with circulating blood and carry a high risk for platelet activation and thrombosis without a stable endothelial cell (EC) monolayer. Development of a healthy endothelium on the blood-contacting surface of these devices would help ameliorate risks associated with thrombus formation and eliminate the need for long-term antiplatelet or anticoagulation therapy. Although ECs have been seeded onto or recruited to these blood-contacting surfaces, most ECs are lost upon exposure to shear stress due to circulating blood. Many investigators have attempted to generate a stable EC monolayer by improving EC adhesion using surface modifications, material coatings, nanofiber topology, and modifications to the cells. Despite some success with enhanced EC retention in vitro and in animal models, no studies to date have proven efficacious for routinely creating a stable endothelium in the clinical setting. This review summarizes past and present techniques directed at improving the adhesion of ECs to blood-contacting devices. Impact statement Clinical success of blood-contacting devices such as vascular grafts, stents, and heart valves has remained limited by postimplantation problems, including thrombosis and loss of patency. Without a stable endothelial cell (EC) monolayer, blood-contacting devices are at risk for platelet activation and thrombosis. Methods to improve EC adhesion on these devices have not translated to long-term in vivo success, as many ECs are lost after exposure to circulating blood. In this study, we summarize methods to improve EC adhesion and retention. Successful endothelialization of blood-contacting devices may improve patient outcomes after device implantation and limit the need for long-term antiplatelet or anticoagulation therapy.

Long-Term Outpatient Care and Rehospitalizations in Patients after Cardiac Electrotherapy Device Implantation.

Background and Objectives: Cardiovascular implantable electronic device (CIED) treatment is widely used in modern cardiology. Indications for this type of treatment are increasing. However, a significant proportion of CIED implantation patients require subsequent hospitalization for cardiovascular reasons. Older age and the associated complex clinical picture necessitate multidisciplinary outpatient specialist care for these patients. The aim of this study was to analyze the reasons for subsequent hospitalizations in the cardiology department and the impact of outpatient specialty care on these hospitalizations. To the best of our knowledge, there are no such studies in the available literature. Materials and Methods: This study was conducted on a population of patients treated with CIED. Reasons for subsequent hospitalizations were divided into clinically and statistically valid groups according to the main diagnosis. Using an electronic database, causes of hospitalization were determined based on this diagnosis. Using data on consultations at outpatient specialty clinics, a logistic regression model was created for the probability of subsequent hospitalization for cardiovascular causes according to the specialty of the clinic. Results: The 9-year follow-up included a population of 2071 patients treated with CIED. During the follow-up period, 508 patients (approximately 24.5%) required subsequent hospitalization for cardiovascular reasons. The most common leading causes were heart failure, atrial fibrillation, and coronary artery disease. The need for consultation at outpatient specialty clinics increased the likelihood of hospitalization. Moreover, the need to consult patients in nephrology outpatient, pulmonary disease outpatient, and orthopedic outpatient clinics was the most significant. Conclusions: The use of electronic implantable cardiovascular devices is a very important part of therapy in modern cardiology. The methods for their use are constantly being improved. However, they represent only one stage of cardiac treatment. After CIED procedures, patients require further care in both inpatient and outpatient specialty care settings. In this paper, we outline the reasons for subsequent hospitalizations and the importance of outpatient specialty care in this context. Effective organization of care after CIED procedures may be important in reducing the most expensive component of this care, that is, inpatient treatment.

Cardiovascular device infections due to rapidly growing Mycobacteria: A review of cases at a tertiary care hospital

Cardiovascular device infection due to rapidly growing mycobacteria (RGM) is rarely encountered in clinical practice. Due to the increasing number of indications and use of cardiovascular devices in an aging population, optimized management of these infections is of great importance. We report seven cases of RGM cardiovascular device infection. Three patients had left-ventricular assist device (LVAD) infections; two patients had cardiovascular implantable device (CIED) infections; and one had an aortic vascular stent infection. Specific cardiac valvular infection was not detected among any of the patients. All patients had a high number of comorbidities which limited some patients from receiving optimal combination antimicrobial therapy. The prognosis of cardiovascular device infections with RGM is guarded with only four patients still alive; however, the treatment approach for each patient varied considerably and often based on concurrent medical conditions, overall adjustments to goals of care, and specific patient preferences. Further analysis of cardiovascular device infections with RGM is warranted to establish a more systematic approach in successful management.

Battery‐Free and Wireless Technologies for Cardiovascular Implantable Medical Devices

AbstractCardiovascular disease continues to be one of the dominant causes of global mortality. One effective treatment is to utilize cardiovascular implantable devices (cIMDs) with multi‐functional cell sensing and monitoring features that have the potential to manipulate cardiovascular hyperplasia disorders as well as provide therapy. However, batteries with a fixed capacity entail high‐risk surgeries for battery‐replacement, which causes health hazards and imposes significant costs to patients. This review accesses comprehensive power solutions for cIMDs, from conventional batteries to state‐of‐the‐art energy harvesters and wireless power transfer (WPT) schemes. In particular, WPT has great potential to eliminate the percutaneous wires and overcome frequent battery removal. Here, the fundamentals, power transfer efficiency, antenna design and miniaturization, and operating frequencies in various WPT schemes are presented. Moreover, the power loss attenuation and bio‐safety standard (specific absorption rate) for implants are also considered in WPT design envelope. In addition, wireless data transmission of implantable devices from external to internal milieu (and vice versa) along with different modulation and demodulation techniques are investigated. The last advanced power solutions for cIMDs in in‐vivo and in vitro research are illustrated throughout. Finally, specifications and future potential of WPT systems in cIMDs are highlighted.

Research and Progress of Implantable Cardiovascular Materials and Devices

Research and Progress of Implantable Cardiovascular Materials and Devices