Journal: Frontiers in Cardiovascular Medicine

Abbreviation

Front. Cardiovasc. Med.

Publisher

Frontiers Media

Journal Volumes

ISSN

2297-055X

Description

Filters

2020 - 202531
Reset filters

Search Results

Publications1 - 10 of 31
  • Physiologic Data-Driven Iterative Learning Control for Left Ventricular Assist Devices
    Item type: Journal Article
    Magkoutas, Konstantinos; Arm, Philip; Meboldt, Mirko; et al. (2022)
    Frontiers in Cardiovascular Medicine
    Continuous flow ventricular assist devices (cfVADs) constitute a viable and increasingly used therapy for end-stage heart failure patients. However, they are still operating at a fixed-speed mode that precludes physiological cfVAD response and it is often related to adverse events of cfVAD therapy. To ameliorate this, various physiological controllers have been proposed, however, the majority of these controllers do not account for the lack of pulsatility in the cfVAD operation, which is supposed to be beneficial for the physiological function of the cardiovascular system. In this study, we present a physiological data- driven iterative learning controller (PDD-ILC) that accurately tracks predefined pump flow trajectories, aiming to achieve physiological, pulsatile, and treatment-driven response of cfVADs. The controller has been extensively tested in an in-silico environment under various physiological conditions, and compared with a physiologic pump flow proportional-integral-derivative controller (PF-PIDC) developed in this study as well as the constant speed (CS) control that is the current state of the art in clinical practice. Additionally, two treatment objectives were investigated to achieve pulsatility maximization and left ventricular stroke work (LVSW) minimization by implementing copulsation and counterpulsation pump modes, respectively. Under all experimental conditions, the PDD-ILC as well as the PF-PIDC demonstrated highly accurate tracking of the reference pump flow trajectories, outperforming existing model-based iterative learning control approaches. Additionally, the developed controllers achieved the predefined treatment objectives and resulted in improved hemodynamics and preload sensitivities compared to the CS support.
  • The path to a hemocompatible cardiovascular implant: Advances and challenges of current endothelialization strategies
    Item type: Review Article
    Exarchos, Vasileios; Zacharova, Ema; Neuber, Sebastian; et al. (2022)
    Frontiers in Cardiovascular Medicine
    Cardiovascular (CV) implants are still associated with thrombogenicity due to insufficient hemocompatibility. Endothelialization of their luminal surface is a promising strategy to increase their hemocompatibility. In this review, we provide a collection of research studies and review articles aiming to summarize the recent efforts on surface modifications of CV implants, including stents, grafts, valves, and ventricular assist devises. We focus in particular on the implementation of micrometer or nanoscale surface modifications, physical characteristics of known biomaterials (such as wetness and stiffness), and surface morphological features (such as gratings, fibers, pores, and pits). We also review how biomechanical signals originating from the endothelial cell for surface interaction can be directed by topography engineering approaches toward the survival of the endothelium and its long-term adaptation. Finally, we summarize the regulatory and economic challenges that may prevent clinical implementation of endothelialized CV implants.
  • Adeno-Associated Virus-Mediated Gain-of-Function mPCSK9 Expression in the Mouse Induces Hypercholesterolemia, Monocytosis, Neutrophilia, and a Hypercoagulative State
    Item type: Journal Article
    Louloudis, Georgios; Ambrosini, Samuele; Paneni, Francesco; et al. (2021)
    Frontiers in Cardiovascular Medicine
    Hypercholesterolemia has previously been induced in the mouse by a single intravenous injection of adeno-associated virus (AAV)-based vector harboring gain-of-function pro-protein convertase subtilisin/kexin type 9. Despite the recent emergence of the PCSK9-AAV model, the profile of hematological and coagulation parameters associated with it has yet to be characterized. We injected 1.0 x 10(11) viral particles of mPCSK9-AAV or control AAV into juvenile male C57BL/6N mice and fed them with either a Western-type high-fat diet (HFD) or standard diet over the course of 3 weeks. mPCSK9-AAV mice on HFD exhibited greater plasma PCSK9 concentration and lower low-density lipoprotein levels, concomitant with increased total cholesterol and non-high-density lipoprotein (non-HDL)-cholesterol concentrations, and lower HDL-cholesterol concentrations than control mice. Furthermore, mPCSK9-AAV-injected mice on HFD exhibited no signs of atherosclerosis at 3 weeks after the AAV injection. Hypercholesterolemia was associated with a thromboinflammatory phenotype, as neutrophil levels, monocyte levels, and neutrophil-to-lymphocyte ratios were higher and activated partial thromboplastin times (aPTTs) was lower in HFD-fed mPCSK9-AAV mice. Therefore, the mPCSK9-AAV is a suitable model of hypercholesterolemia to examine the role of thromboinflammatory processes in the pathogenesis of cardiovascular and cerebrovascular diseases.
  • Detection of heart rate using smartphone gyroscope data: a scoping review
    Item type: Review Article
    Wu, Wenshan; Elgendi, Mohamed; Fletcher, Richard Ribon; et al. (2023)
    Frontiers in Cardiovascular Medicine
    Heart rate (HR) is closely related to heart rhythm patterns, and its irregularity can imply serious health problems. Therefore, HR is used in the diagnosis of many health conditions. Traditionally, HR has been measured through an electrocardiograph (ECG), which is subject to several practical limitations when applied in everyday settings. In recent years, the emergence of smartphones and microelectromechanical systems has allowed innovative solutions for conveniently measuring HR, such as smartphone ECG, smartphone photoplethysmography (PPG), and seismocardiography (SCG). However, these measurements generally rely on external sensor hardware or are highly susceptible to inaccuracies due to the presence of significant levels of motion artifact. Data from gyrocardiography (GCG), however, while largely overlooked for this application, has the potential to overcome the limitations of other forms of measurements. For this scoping review, we performed a literature search on HR measurement using smartphone gyroscope data. In this review, from among the 114 articles that we identified, we include seven relevant articles from the last decade (December 2012 to January 2023) for further analysis of their respective methods for data collection, signal pre-processing, and HR estimation. The seven selected articles' sample sizes varied from 11 to 435 participants. Two articles used a sample size of less than 40, and three articles used a sample size of 300 or more. We provide elaborations about the algorithms used in the studies and discuss the advantages and disadvantages of these methods. Across the articles, we noticed an inconsistency in the algorithms used and a lack of established standardization for performance evaluation for HR estimation using smartphone GCG data. Among the seven articles included, five did not perform any performance evaluation, while the other two used different reference signals (HR and PPG respectively) and metrics for accuracy evaluation. We conclude the review with a discussion of challenges and future directions for the application of GCG technology.
  • Plasma Hydrogen Sulfide Is Positively Associated With Post-operative Survival in Patients Undergoing Surgical Revascularization
    Item type: Journal Article
    Longchamp, Alban; MacArthur, Michael R.; Trocha, Kaspar; et al. (2021)
    Frontiers in Cardiovascular Medicine
    Objective: Hydrogen sulfide (H2S) is a gaseous signaling molecule and redox factor important for cardiovascular function. Deficiencies in its production or bioavailability are implicated in atherosclerotic disease. However, it is unknown if circulating H2S levels differ between vasculopaths and healthy individuals, and if so, whether H2S measurements can be used to predict surgical outcomes. Here, we examined: (1) Plasma H2S levels in patients undergoing vascular surgery and compared these to healthy controls, and (2) the association between H2S levels and mortality in a cohort of patients undergoing surgical revascularization. Methods: One hundred and fifteen patients undergoing carotid endarterectomy, open lower extremity revascularization or lower leg amputation were enrolled at a single institution. Peripheral blood was also collected from a matched control cohort of 20 patients without peripheral or coronary artery disease. Plasma H2S production capacity and sulfide concentration were measured using the lead acetate and monobromobimane methods, respectively. Results: Plasma H2S production capacity and plasma sulfide concentrations were reduced in patients with PAD (p < 0.001, p = 0.013, respectively). Patients that underwent surgical revascularization were divided into high vs. low H2S production capacity groups by median split. Patients in the low H2S production group had increased probability of mortality (p = 0.003). This association was robust to correction for potentially confounding variables using Cox proportional hazard models. Conclusion: Circulating H2S levels were lower in patients with atherosclerotic disease. Patients undergoing surgical revascularization with lower H2S production capacity, but not sulfide concentrations, had increased probability of mortality within 36 months post-surgery. This work provides insight on the role H2S plays as a diagnostic and potential therapeutic for cardiovascular disease.
  • Corrigendum: Adeno-Associated Virus-Mediated Gain-of-Function mPCSK9 Expression in the Mouse Induces Hypercholesterolemia, Monocytosis, Neutrophilia, and a Hypercoagulative State
    Item type: Other Journal Item
    Louloudis, Georgios; Ambrosini, Samuele; Paneni, Francesco; et al. (2022)
    Frontiers in Cardiovascular Medicine
  • Machine learning for predicting acute hypotension: A systematic review
    Item type: Review Article
    Zhao, Anxing; Elgendi, Mohamed; Menon, Carlo (2022)
    Frontiers in Cardiovascular Medicine
    An acute hypotensive episode (AHE) can lead to severe consequences and complications that threaten patients' lives within a short period of time. How to accurately and non-invasively predict AHE in advance has become a hot clinical topic that has attracted a lot of attention in the medical and engineering communities. In the last 20 years, with rapid advancements in machine learning methodology, this topic has been viewed from a different perspective. This review paper examines studies published from 2008 to 2021 that evaluated the performance of various machine learning algorithms developed to predict AHE. A total of 437 articles were found in four databases that were searched, and 35 full-text articles were included in this review. Fourteen machine learning algorithms were assessed in these 35 articles; the Support Vector Machine algorithm was studied in 12 articles, followed by Logistic Regression (six articles) and Artificial Neural Network (six articles). The accuracy of the algorithms ranged from 70 to 96%. The size of the study sample varied from small (12 subjects) to very large (3,825 subjects). Recommendations for future work are also discussed in this review.
  • Assessment of Blood Pressure Using Only a Smartphone and Machine Learning Techniques: A Systematic Review
    Item type: Review Article
    Haugg, Fridolin; Elgendi, Mohamed; Menon, Carlo (2022)
    Frontiers in Cardiovascular Medicine
    Regular monitoring of blood pressure (BP) allows for early detection of hypertension and symptoms related to cardiovascular disease. Measuring BP with a cuff requires equipment that is not always readily available and it may be impractical for some patients. Smartphones are an integral part of the lives of most people; thus, detecting and monitoring hypertension with a smartphone is likely to increase the ability to monitor BP due to the convenience of use for many patients. Smartphones lend themselves to assessing cardiovascular health because their built-in sensors and cameras provide a means of detecting arterial pulsations. To this end, several image processing and machine learning (ML) techniques for predicting BP using a smartphone have been developed. Several ML models that utilize smartphones are discussed in this literature review. Of the 53 papers identified, seven publications were evaluated. The performance of the ML models was assessed based on their accuracy for classification, the mean error measure, and the standard deviation of error for regression. It was found that artificial neural networks and support vector machines were often used. Because a variety of influencing factors determines the performance of an ML model, no clear preference could be determined. The number of input features ranged from five to 233, with the most commonly used being demographic data and the features extracted from photoplethysmogram signals. Each study had a different number of participants, ranging from 17 to 5,992. Comparisons of the cuff-based measures were mostly used to validate the results. Some of these ML models are already used to detect hypertension and BP but, to satisfy possible regulatory demands, improved reliability is needed under a wider range of conditions, including controlled and uncontrolled environments. A discussion of the advantages of various ML techniques and the selected features is offered at the end of this systematic review.
  • Real-World Outcomes of Revascularization Strategies in Patients With Left Ventricular Dysfunction and Three-Vessel Coronary Disease Stratified by Mitral Regurgitation
    Item type: Journal Article
    Fan, Qin; Liu, Jun; Xu, Yan; et al. (2021)
    Frontiers in Cardiovascular Medicine
    Aims: Limited information exists regarding optimal revascularization options for patients with triple-vessel coronary artery disease (TVD), heart failure (HF), and different degrees of mitral regurgitation (MR). Thus, we aimed to compare the effect of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) surgery in the indicated patients. Methods and Results: In the real-world prospective study, 1190 patients with multi-vessel disease and decreased left ventricular systolic function but without severe MR, who underwent PCI or CABG, were enrolled and followed-up for 4.7 ± 1.8 years. The primary endpoint was a composite of cardiovascular death and HF hospitalization. Secondary endpoints were the individual components of the primary outcome. Risk of the primary endpoint was higher in the PCI than in the CABG group (HR = 1.38, 95%CI: 1.14–1.67, and P < 0.01), particularly in patients with moderate MR (HR = 1.85, 95%CI: 1.35–2.55, and P < 0.01). In patients with no-mild MR, the risk of the primary endpoint did not differ significantly between PCI and CABG (P = 0.09). Treatment with PCI was associated with an increased risk for cardiovascular death and HF hospitalization in the moderate MR cohort, while PCI was comparable to CABG in the no-mild MR cohort. Conclusions: In this real-world study, for patients with HF and TVD, CABG was related to lower adverse outcome rates compared to PCI. Assessment of MR can aid in selecting optimal revascularization therapies and in risk stratification.
  • High Density Lipoproteins: Metabolism, Function, and Therapeutic Potential
    Item type: Review Article
    Jomard, Anne; Osto, Elena (2020)
    Frontiers in Cardiovascular Medicine
    High Density Lipoproteins (HDLs) have long been considered as “good cholesterol,” beneficial to the whole body and, in particular, to cardio-vascular health. However, HDLs are complex particles that undergoes dynamic remodeling through interactions with various enzymes and tissues throughout their life cycle, making the complete understanding of its functions and roles more complicated than initially expected. In this review, we explore the novel understanding of HDLs' behavior in health and disease as a multifaceted class of lipoprotein, with different size subclasses, molecular composition, receptor interactions, and functionality. Further, we report on emergent HDL-based therapeutics tested in small and larger scale clinical trials and their mixed successes.
Publications1 - 10 of 31