Search Results (41)

Continuous blood pressure (BP) monitoring provides valuable insight into the body’s dynamic cardiovascular regulation across various physiological states such as physical activity, emotional stress, postural changes, and sleep. Continuous BP monitoring captures different variations in systolic and diastolic pressures, reflecting autonomic nervous system activity, vascular compliance, and circadian rhythms. This enables early identification of abnormal BP trends and allows for timely diagnosis and interventions to reduce the risk of cardiovascular diseases (CVDs) such as hypertension, stroke, heart failure, and chronic kidney disease as well as chronic stress or anxiety disorders. To facilitate continuous BP monitoring, we propose an AI-powered estimation framework. The proposed framework first uses an expert-driven feature engineering approach that systematically extracts physiological features from photoplethysmogram (PPG)-based arterial pulse waveforms (APWs). Extracted features include pulse rate, ascending/descending times, pulse width, slopes, intensity variations, and waveform areas. These features are fused with demographic data (age, gender, height, weight, BMI) to enhance model robustness and accuracy across diverse populations. The framework utilizes a Tab-Transformer to learn rich feature embeddings, which are then processed through an ensemble machine learning framework consisting of CatBoost, XGBoost, and LightGBM. Evaluated on a dataset of 1000 subjects, the model achieves Mean Absolute Errors (MAE) of 3.87 mmHg (SBP) and 2.50 mmHg (DBP), meeting British Hypertension Society (BHS) Grade A and Association for the Advancement of Medical Instrumentation (AAMI) standards. The proposed architecture advances non-invasive, AI-driven solutions for dynamic cardiovascular health monitoring. Full article

Fontan circulation is a fragile system in which imperfections at any of multiple levels may compromise the quality of life, produce secondary pathophysiology, and shorten life span. Increased inferior vena caval pressure itself may play a role in “Fontan failure”. This study describes a mock flow loop model (MFL) designed to quantitatively estimate pulmonary flow entrainment induced by continuous and pulsed flow injections. A patient generic 3D-printed phantom model of the total cavopulmonary connection (TCPC) with average dimensions matching those of a 2–4-year-old patient was inserted in an MFL derived from a reduced lumped parameter model (LPM) representing cardiovascular circulation. The LPM comprises four 2-element Windkessel compartments (compliance and resistance), approximating the upper and lower systemic circulations and the right and left pulmonary circulations. The prescribed cardiac output is about 2.3 L/min for a body surface area of $0.675{ \mathrm{m}}^2$. The injections originate from an external pump through a 7–9 fr catheter, following a strict protocol suggested by the clinical team, featuring a variation in injection rate (flow rate), injection volume, and injection modality (continuous or pulsed). The key measurements in this study are the flow rates sampled at the distal pulmonary arteries, as well as at the upper and lower body boundaries. These measurements were then used to calculate effective entrainment as the difference between the measured and expected flow rates, as well as jet relaxation (rise and fall time of injection). The results show that for continuous or pulsed injections, varying the total volume injected has no significant influence on the entrainment rate across all injection rates. On the other hand, for both injection modalities, increasing the injection rate results in a reduction in entrainment that is consistent across all injected volumes. This study demonstrates the effectiveness of a high-speed injection jet entraining a slow co-flow while determining the potential for fluid buildup, which could ultimately cause an increase in caval pressure. To avoid the increase in caval pressure due to mass accumulation, we added a fenestration to our proposed injection jet shunt-assisted Fontan models. It was found that for a set of well-defined parameters, the jet not only can be beneficial to the local flow, but any adverse effect can be obviated by careful tuning. These results were also cross-validated with similar in silico findings. Full article

The sympathetic division of the autonomic nervous system plays a crucial role in maintaining homeostasis, but its overactivity is implicated in various pathological conditions, including hypertension, hyperglycaemia, heart failure, and rheumatoid arthritis. Traditional pharmacotherapies often face limitations such as side effects and poor patient adherence, thus prompting the exploration of device-based multi-organ denervation as a therapeutic strategy. Crucially, this procedure can potentially offer therapeutic benefits throughout the 24 h circadian cycle, described as an “always-on” effect independent of medication compliance and pharmacokinetics. In this comprehensive review, we evaluate the evidence behind targeted multi-organ sympathetic denervation by considering the anatomy and function of the autonomic nervous system, examining the evidence linking sympathetic nervous system overactivity to various cardiometabolic and inflammatory conditions and exploring denervation studies within the literature. So far, renal denervation, developed in 2010, has shown promise in reducing blood pressure and may have broader applications for conditions including arrhythmias, glucose metabolism disorders, heart failure, chronic kidney disease and obstructive sleep apnoea. We review the existing literature surrounding the denervation of other organ systems including the hepatic and splenic arteries, as well as the pulmonary artery and carotid body, which may provide additional physiological benefits and enhance therapeutic effects if carried out simultaneously. Furthermore, we highlight the challenges and future directions for implementing multi-organ sympathetic ablation, emphasising the need for further clinical trials to establish optimal procedural technique, efficacy and safety. Full article

Noninvasive blood pressure (NIBP) device performance in dogs may be influenced by extreme pressures and altered systemic vascular resistance (SVR). This study evaluated the agreement of two NIBP devices (HDO and petMAP) with invasive blood pressure (IBP) measurements, compliance with hypertension consensus statement criteria, and their trending ability (TA) across varying blood pressure and SVR ranges in awake and anesthetized dogs. Seven healthy Beagles were studied, with IBP recorded from the dorsal metatarsal artery and NIBP cuffs placed randomly on the front limb, hind limb, or base of the tail. Cardiac output was determined by thermodilution, and the systemic vascular resistance index (SVRI) was calculated by a standard formula. Bland–Altman, concordance rate, and polar plot analyses were used for statistical analysis. A total of 752 and 640 paired measurements were obtained for HDO and petMAP, respectively. Both devices showed good agreement with IBP for mean arterial pressure (MAP) at low blood pressure and the SVRI. At high blood pressure and the SVRI, agreement weakened, with substantial underestimation of systolic arterial pressure (SAP). Both devices demonstrated moderate to good TA for MAP and SAP. Overall, the best agreement was observed for MAP at a low SVRI, while agreement was moderate at hypertension (petMAP) and a high SVRI (petMAP, HDO). Full article

This study proposes an innovative mathematical model for assessing microcirculation in patients with diabetic ulcers, using the ankle–brachial index (ABI). The methodology combines Bond Graph (BG) modeling and Particle Swarm Optimization (PSO), enabling a detailed analysis of hemodynamic patterns in a pilot sample of three patients. The results revealed a correlation between ulcer size and reduced ABI values, suggesting that deficits in microcirculation directly impact the severity of lesions. Furthermore, despite variations in ABI values and arterial pressures, all patients exhibited high capillary resistance, indicating difficulties in microcirculatory blood flow. The PSO-optimized parameters for the capillary equivalent circuit were found to be $R_1=89.784\Omega$, $R_2=426.55\Omega$, $L=27.506\mathrm{H}$, and $C=0.00040675\mathrm{F}$, which confirms the presence of high vascular resistance and reduced compliance in the microvascular system of patients with diabetic foot ulcers. This quantitative analysis, made possible through mathematical modeling, is crucial for detecting subtle changes in microcirculatory dynamics, which may not be easily identified through conventional pressure measurements alone. The increased capillary resistance observed may serve as a key indicator of vascular impairment, potentially guiding early intervention strategies and optimizing diabetic ulcer treatment. We acknowledge that the sample size of three patients represents a limitation of the study, but this number was intentionally chosen to allow for a detailed and controlled analysis of the variables involved. Although the findings are promising, additional experimental validations are necessary to confirm the clinical applicability of the model in a larger patient sample, thus solidifying its relevance in clinical practice. Full article

The aim of this study was to assess the applicability of the Mechanical Systems Coordination Working Group’s (MSCWG) findings, based on FAR 25.831(g), to Chinese pilots through a human physiological experiment conducted in a high-temperature environment to investigate the effects of core temperature. Methods: A controlled experiment was carried out in a high-temperature environment simulation room involving a cohort of healthy males aged 18–50 years. Wireless physiological monitoring equipment and a neurobehavioral assessment system were utilized to track changes in physiological parameters and neurobehavioral responses at varying core temperatures and time intervals. Results: There was a significant increase in human core body temperature, skin temperature, and heart rate as the ambient temperature rose, all remaining within acceptable physiological limits. Although arterial and venous oxygen saturation decreased with increasing ambient temperature, the difference was not statistically significant. The neurobehavioral abilities of the subjects did not exhibit notable changes across different core temperature–time conditions. Conclusions: The core temperature limits set forth by the MSCWG have been shown to have a safe impact on the physiological and behavioral aspects of Chinese pilots, which can be used as an equivalent safety regulation for airworthiness compliance validation under CCAR 25.831(g). Limitation: The present study was constrained to a male sample, it did not thoroughly explore female responses, and it had a small sample size (10 per group). The latter two factors may have affected the statistical validity and generalizability of the results. Full article

Objectives: This study aimed to examine the effects of endurance and high-intensity resistance training on arterial stiffness and ventricular repolarization in elite athletes. Methods: A total of 50 male athletes from different sports disciplines (volleyball, football, judo, and wrestling) and a sedentary group of 30 males participated in this study. Data collected from all participants included age, height, body weight, cardiovascular hemodynamic parameters, arterial stiffness parameters, and ECG measurements. Results: There was no significant age difference between the athlete group (20.42 ± 1.903 years) and the control group (20.97 ± 1.771 years) (p > 0.05). However, body mass index (BMI) values in the control group (24.83 ± 2.22 kg/m²) were significantly different from those in the athlete group (22.39 ± 2.663 kg/m²) (p < 0.05). Significant differences were found between the athlete and control groups in QT dispersion, systolic blood pressure, pulse pressure, and central pulse pressure values (p < 0.05), while similar results were obtained for arterial stiffness parameters (p > 0.05). Conclusions: The lack of a difference in pulse wave velocity and augmentation index (AIx) values between the athletes and the control group suggests that athletes do not bear additional risks regarding arterial stiffness. However, increased systolic blood pressure, pulse pressure, and central pulse pressure, among the hemodynamic parameters, indicate potential variations in vascular wall compliance and hemodynamic responses in the cardiovascular system. The increase in QT dispersion suggests that athletes may exhibit a heterogeneous repolarization process and an elevated risk of ventricular arrhythmias compared to the general population. Full article

Objective: The study aimed to assess the potential impacts of mean arterial pressure (MAP) and its determinants (cardiac output and systemic vascular resistance) on diabetic nephropathy (DNP)-associated impaired aortic function. Methods: This multi-ethnic study included 115 chronic kidney disease (CKD) patients (67 non-dialysis and 48 dialysis). Six aortic function measures were evaluated by SpygmoCor. The stroke volume was determined by echocardiography. Results: Hypertensive nephropathy (HNP) (53.9%), DNP (32.2%), glomerulonephritis (19.1%), and HIV-associated nephropathy (7.8%) composed the major CKD etiologies. Concurrent HNP and DNP were present in 31.1% of the patients. Participants with compared with those without concurrent HNP and DNP experienced more frequent established cardiovascular disease (43.2% versus 14.9%, p = 0.01), a faster pulse wave velocity (p = 0.001), and smaller total arterial compliance as an indicator of proximal aortic stiffness (p = 0.03). DNP was associated with each aortic function measure (p < 0.001–0.02) independent of potential confounders and MAP, as well as its determinants. HNP was not related to aortic function (p > 0.05 for all relationships). MAP and its determinants did not mediate the potential impact of DNP on aortic function (−4.1–6.4% contribution). Covariates that were associated with impaired aortic function measures included MAP and its determinants (p < 0.001–0.01). Conclusions: Mean or distending arterial pressure and its determinants were associated with impaired aortic function in the overall CKD population. However, these hemodynamic factors did not mediate DNP-associated impaired aortic function. Our results suggest that blood pressure lowering can be anticipated to improve impaired aortic function in the overall CKD population but not when it is solely induced by DNP. Full article

Background: The generation and perfusion of complex vascularized tissues in vitro requires sophisticated perfusion techniques. For multiscale arteriovenous networks, not only the arterial, but also the venous, biomechanical and biochemical conditions that physiologically exist in the human body must be accurately emulated. For this, we here present a modular arteriovenous perfusion system for the in vitro culture of a multi-scale bioartificial vascular network. Methods: The custom-built perfusion system consisted of two circuits: in the arterial circuit, physiological arterial biomechanical and biochemical conditions were simulated using a modular set-up with a pulsatile peristaltic pump, compliance chambers, and resistors. In the venous circuit, venous conditions were emulated accordingly. In the center of the system, a bioartificial multi-scale vascularized fibrin-based tissue was perfused by both circuits simultaneously under biomimetic arteriovenous conditions. Culture conditions were monitored continuously using a multi-sensor monitoring system. Results: The physiological arterial and venous pressure- and flow-curves, as well as the microvascular arteriovenous oxygen partial pressure gradient, were accurately emulated in the perfusion system. The multi-sensor monitoring system facilitated live monitoring of the respective parameters and data-logging. In a proof-of-concept experiment, vascularized three-dimensional fibrin tissues showed sustained cell viability and homogenous microvessel formation after culture in the perfusion system. Conclusions: The arteriovenous perfusion system facilitated the in vitro culture of a multiscale vascularized tissue under physiological pressure-, flow-, and oxygen-gradient conditions. With that, it presents a promising technique for the in vitro generation and culture of complex large-scale vascularized tissues. Full article

Acute respiratory failure (ARF) is a sudden failure of the respiratory system to ensure adequate gas exchanges. Numerous clinical conditions may cause ARF, including pneumonia, obstructive lung diseases (e.g., asthma), restrictive diseases such as neuromuscular diseases (e.g., spinal muscular atrophy and muscular dystrophy), and albeit rarely, interstitial lung diseases. Children, especially infants, may be more vulnerable to ARF than adults due to anatomical and physiological features of the respiratory system. Assessing respiratory impairment in the pediatric population is particularly challenging as children frequently present difficulties in reporting symptoms and due to compliance and cooperation in diagnostic tests. The evaluation of clinical and anamnestic aspects represents the cornerstone of ARF diagnosis: first level exams (e.g., arterial blood gas analysis) confirm and evaluate the severity of the ARF and second level exams help to uncover the underlying cause. Prompt management is critical, with supplemental oxygen, mechanical ventilation, and the treatment of the underlying problem. The aim of this review is to provide a comprehensive summary of the current state of the art in diagnosing pediatric ARF, with a focus on pathophysiology, novel imaging applications, and new perspectives, such as biomarkers and artificial intelligence. Full article

Background/Objectives: Bladder outlet obstruction (BOO) resulting from benign prostate enlargement (BPE) is a common cause of lower urinary tract symptoms (LUTS) in men. Patients with central nervous system (CNS) diseases, such as spinal cord injury (SCI), Parkinson’s disease (PD), cerebrovascular accident (CVA) and multiple systemic atrophy (MSA), commonly experience lower urinary tract dysfunction. Men who suffer from CNS diseases may also experience symptoms related to BPE and BOO, which pose an additional burden to their overall clinical status and result in the need for catheter use and a deterioration in quality of life. The aim of this study was to identify if prostate surgery will benefit men with CNS diseases who have been diagnosed with BPE-related BOO. Methods: The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. EMBASE, MEDLINE, Cochrane systematic reviews, Cochrane Central Register of Controlled Trials, Google Scholar, and ClinicalTrials.gov were searched from 1946 up to July 2023 for peer-reviewed publications addressing the primary outcome (success rate) and the secondary outcomes (postoperative changes in incontinence episodes, urodynamic parameters, questionnaire scores, and quality of life). In addition, the perioperative outcomes (adverse events and the need for further medical or surgical therapy) were reported. Results: A total of 1572 abstracts were screened, and 13 studies involving 1144 patients were eligible for inclusion. Six studies assessed the effect of prostate surgery for BPE-related BOO in SCI, four studies in CVA, two studies in PD, and one study in the MSA population. All studies were considered to have a high risk of bias. Transurethral resection of the prostate (TURP) was the most common de-obstruction procedure, followed by prostatic artery embolism and open prostatectomy. The overall pooled success rate was calculated as 81.4% (65–100%) in SCI, 27.1% (9–70%) in PD, and 66.7% (50–79%) in CVA populations. The risk of de novo incontinence was 24.7–50% in SCI, 20% in PD, 21–50% in CVA, and 60% in MSA population. In patients with SCI with BPE-related BOO, prostate surgery improved mean bladder compliance and detrusor filling pressure and resolved detrusor overactivity in up to 50% of patients. Improvement of free flow rate, voided volume, and post-void residual was observed in all patients. Patients with CVA had an increased risk of perioperative mortality compared to non-CVA patients, and the risk of postoperative complications was inversely proportional to the timing of the CVA insult since surgery. Conclusions: This systematic review provides an overview of the available evidence on the outcome of prostate surgery in patients with neurologic diseases and BPE-related BOO. Identifying the optimal practice was challenging due to the limited availability of high-quality studies and the high variability of the reported outcomes. Properly selected patients with neurological diseases may benefit from prostate surgery, provided that preoperative investigations indicate BPE-related BOO. Full article

Background/Objectives: Acromegaly-induced prolonged exposure to growth hormone and insulin-like growth factor 1 may have significant cardiovascular effects. The purpose of this study was to assess the relationship between hemodynamic parameters measured via impedance cardiography (ICG) and parameters of systolic left ventricular function measured via echocardiography in patients with acromegaly. Methods: The observational cohort study included 33 patients with newly diagnosed acromegaly, with a mean age of 47 years and without significant comorbidities. Correlation analysis (Spearman’s rank correlation coefficient R) was performed on parameters obtained by ICG and left ventricular systolic function parameters obtained by echocardiography. ICG assessment included indices of (1) cardiac function as a pump: stroke volume index (SI), cardiac index (CI), Heather index (HI), velocity index (VI), and acceleration index (ACI); (2) afterload: systemic vascular resistance index (SVRI) and total arterial compliance index (TACI); and (3) thoracic fluid content (TFC). Echocardiographic examinations evaluated left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). Results: A lower LVEF was associated with a lower SI (R = 0.38; p = 0.03) and a higher SVRI (R = −0.35; p = 0.046), whereas lower GLS was associated with lower SI (R = 0.43; p = 0.02), CI (R = 0.62; p < 0.001), VI (R = 0.59; p < 0.001), ACI (R = 0.38; p = 0.048), HI (R = 0.59; p < 0.001), and TACI (R = 0.50; p = 0.006) and a higher SVRI (R = −0.59; p < 0.001). No significant correlation was observed between either LVEF or GLS and TFC. Conclusions: In patients with acromegaly, poorer echocardiographic parameters of left ventricular systolic function are associated with impaired function of the heart as a pump and higher afterload as assessed via ICG. Full article

Calcified and resistant narrowing of arteries poses significant difficulty in performing percutaneous coronary interventions (PCIs), as they increase the risk of subpar outcomes leading to worse clinical outcomes. Despite the existence of dedicated technologies and devices, including various balloons and atherectomy systems, they often do not ensure sufficient plaque modification and ideal vessel preparation for optimal stent deployment. Intravascular lithotripsy (IVL), a technology originally developed for urological procedures, has recently been used to safely and selectively disrupt calcified depositions in both peripheral and coronary arteries by sonic waves that seamlessly transfer to nearby tissue, enhancing vessel compliance with minimal impact on soft tissues. In the coronary arteries, the use of IVL plays a role in the process of “vessel preparation” before the placement of stents, which is crucial for restoring blood flow in patients with severe coronary artery disease (CAD), and is considered a minimally invasive technique, reducing the need for open heart surgeries and associated risks and complications. Studies have shown that IVL can lead to improved procedural success rates and favorable long-term outcomes for patients with severely calcified coronary artery disease. With the advent of IVL, the disruption of severe calcification of coronary artery and stenotic lesions before stent implantations can be performed. Despite promising data for treating calcified lesions, IVL is significantly underutilized in clinical practice, long-term clinical data and extensive research are needed to validate its further safety and efficacy. In this article, we reviewed the literature discussing the use of IVL in the coronary arteries as an approach for addressing intravascular atherosclerotic plaques, particularly focusing on heavily calcified plaques that are resistant to standard initial PCI, while also evaluating its safety in comparison to alternative methods. Full article

Bronchopulmonary dysplasia (BPD) remains the most common respiratory disorder of prematurity for infants born before 32 weeks of gestational age (GA). Early and prolonged exposure to chronic hypoxia and inflammation induces pulmonary hypertension (PH) with the characteristic features of a reduced number and increased muscularisation of the pulmonary arteries resulting in an increase in the pulmonary vascular resistance (PVR) and a fall in their compliance. BPD and BPD-associated pulmonary hypertension (BPD-PH) together with systemic hypertension (sHTN) are chronic cardiopulmonary disorders which result in an increased mortality and long-term problems for these infants. Previous studies have predominantly focused on the pulmonary circulation (right ventricle and its function) and developing management strategies accordingly for BPD-PH. However, recent work has drawn attention to the importance of the left-sided cardiac function and its impact on BPD in a subset of infants arising from a unique pathophysiology termed postcapillary PH. BPD infants may have a mechanistic link arising from chronic inflammation, cytokines, oxidative stress, catecholamines, and renin–angiotensin system activation along with systemic arterial stiffness, all of which contribute to the development of BPD-sHTN. The focus for the treatment of BPD-PH has been improvement of the right heart function through pulmonary vasodilators. BPD-sHTN and a subset of postcapillary PH may benefit from afterload reducing agents such as angiotensin converting enzyme inhibitors. Preterm infants with BPD-PH are at risk of later cardiac and respiratory morbidities as young adults. This paper reviews the current knowledge of the pathophysiology, diagnosis, and treatment of BPD-PH and BPD-sHTN. Current knowledge gaps and emerging new therapies will also be discussed. Full article

As a regulator of alveolo-capillary barrier integrity, Transient Receptor Potential Vanilloid 4 (TRPV4) antagonism represents a promising strategy for reducing pulmonary edema secondary to chemical inhalation. In an experimental model of acute lung injury induced by exposure of anesthetized swine to chlorine gas by mechanical ventilation, the dose-dependent effects of TRPV4 inhibitor GSK2798745 were evaluated. Pulmonary function and oxygenation were measured hourly; airway responsiveness, wet-to-dry lung weight ratios, airway inflammation, and histopathology were assessed 24 h post-exposure. Exposure to 240 parts per million (ppm) chlorine gas for ≥50 min resulted in acute lung injury characterized by sustained changes in the ratio of partial pressure of oxygen in arterial blood to the fraction of inspiratory oxygen concentration (PaO₂/FiO₂), oxygenation index, peak inspiratory pressure, dynamic lung compliance, and respiratory system resistance over 24 h. Chlorine exposure also heightened airway response to methacholine and increased wet-to-dry lung weight ratios at 24 h. Following 55-min chlorine gas exposure, GSK2798745 marginally improved PaO₂/FiO₂, but did not impact lung function, airway responsiveness, wet-to-dry lung weight ratios, airway inflammation, or histopathology. In summary, in this swine model of chlorine gas-induced acute lung injury, GSK2798745 did not demonstrate a clinically relevant improvement of key disease endpoints. Full article