Search Results (152)

Obstructive sleep apnea (OSA) is a sleep-related respiratory disorder characterized by partial or complete obstruction of the upper airway, typically resulting in a decrease in arterial oxygen saturation and repeated awakenings from sleep. It is the most common sleep-related respiratory disorder, affecting 9% to 38% of adults. OSA is associated with loss of tone, improper contraction of the tongue, and pharyngeal dilator muscles of the upper airway during sleep. The gold-standard treatment for moderate-to-severe OSA is continuous positive airway pressure (CPAP). However, many patients have poor long-term compliance with CPAP. Stimulation of the upper airway with electrical activation of the hypoglossal nerve has emerged as a promising treatment for patients with moderate-to-severe OSA who have failed CPAP therapy. Objectives: The present paper aims to review the literature regarding neurostimulation for the treatment of OSA. Conclusions: Hypoglossal nerve stimulation (HNS) has shown favorable success and low morbidity in the management of moderate-to-severe OSA. Full article

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

Right heart failure (RHF) is a major cause of morbidity and mortality, often resulting from pulmonary arterial hypertension and characterized by impaired calcium (Ca²⁺) handling and maladaptive remodeling. Phosphodiesterase 9A (PDE9A), a cGMP-specific phosphodiesterase, has been proposed as a potential contributor to RHF pathogenesis by suppressing the cardioprotective cGMP–PKG signaling pathway—a conclusion largely extrapolated from left-sided heart failure models. This review examines existing evidence regarding PDE9A’s role in RHF, focusing on its effects on intracellular calcium cycling, fibrosis, hypertrophy, and contractile dysfunction. Data from preclinical models demonstrate that pathological stress upregulates PDE9A expression in cardiomyocytes, leading to diminished PKG activation, impaired SERCA2a function, RyR2 instability, and increased arrhythmogenic Ca²⁺ leak. Pharmacological or genetic inhibition of PDE9A restores cGMP signaling, improves calcium handling, attenuates hypertrophic and fibrotic remodeling, and enhances ventricular compliance. Early-phase clinical studies in heart failure populations suggest that PDE9A inhibitors are well tolerated and effectively augment cGMP levels, although dedicated trials in RHF are still needed. Overall, these findings indicate that targeting PDE9A may represent a promising therapeutic strategy to improve outcomes in RHF by directly addressing the molecular mechanisms underlying calcium mishandling and myocardial remodeling. Full article

Objectives: This review explores the current evidence on how different massage modalities, either manual (MM) or using foam rolling (FR), with or without strength training, influence cardiovascular and autonomic function in healthy individuals. Methods: A search was performed in CINAHL, Cochrane Library, PubMed^®, and SciELO databases on 14 April 2025. Results: Among the 5125 studies retrieved in the database search, 7 were selected for the present review. The included studies pointed to an improvement in hemodynamic and autonomic responses, characterized by reduced arterial stiffness and blood pressure and an increase in nitric oxide concentration and blood flow. These findings suggest that physical exercise prescribers should consider the hemodynamic and autonomic effects promoted by massage (MM or FR). Conclusions: A change in arterial compliance, followed by a hypotensive effect on systolic blood pressure, reinforces the role of physical activity as a non-pharmacological agent and highlights the need for inclusion in the different groups that need adjuvant help for blood pressure control. 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

Transcatheter aortic valve replacement (TAVR) has become a well-established treatment for severe aortic stenosis across all levels of surgical risk. While transfemoral access remains the default approach, complications arising from vascular access—especially in patients with peripheral artery disease (PAD)—pose significant challenges. Hostile vascular access, characterized by narrow vessel diameters, severe calcification, and tortuosity, complicates the procedure and necessitates alternative strategies. Recent advancements, such as intravascular lithotripsy (IVL), have shown promise in managing severely calcified arteries, improving the feasibility of transfemoral TAVR in patients previously considered ineligible. IVL uses pulsatile sonic waves to fragment arterial calcifications, enhancing vessel compliance and facilitating safe device delivery. Studies have demonstrated that IVL-assisted TAVR improves procedural success and reduces complications in patients with PAD. Additionally, orbital atherectomy, an adjunctive therapy targeting both concentric and eccentric calcifications, may complement the management of complex arterial calcification. The Hostile and passage–puncture scores offer valuable risk stratification tools for predicting vascular complications, aiding in better access site selection. Post-procedural echocardiography, particularly femoral artery sonography, may also play a role in detecting vascular complications early, enabling timely intervention. Finally, alternative access sites are increasingly being explored, with emerging data helping to guide the final access site decision. As TAVR continues to expand into lower risk populations, optimizing vascular access strategies remains essential to improving procedural outcomes. This review highlights the importance of preoperative imaging, endovascular techniques, and post-procedural monitoring in overcoming vascular challenges and ensuring successful TAVR outcomes. Full article

Nitric oxide (NO), an endogenous vasodilator, has been proposed as a biomarker for pulmonary hypertension (PH) in humans. NO is synthesized by endothelial nitric oxide synthase (eNOS). Alterations in NO/eNOS have not been studied in dogs with PH. We assessed alterations in NO and eNOS in the blood of dogs with PH (n = 17) and healthy dogs (n = 10) and analyzed their correlations with echocardiographic parameters. The results showed significantly higher plasma NO and serum eNOS levels in dogs with PH compared with healthy dogs. Dogs with PH and ascites (n = 11) had significantly lower plasma NO levels than those without ascites (n = 6) and presented a decreasing eNOS trend. In dogs with PH, plasma NO was positively correlated with left ventricular hemodynamics, right ventricular compliance, and pulmonary distensibility, but was negatively correlated with pulmonary vascular resistance and right cardiac remodeling. Serum eNOS was positively correlated with the main pulmonary artery diameter. Increments in NO/eNOS reflected compensatory responses to cardiovascular changes in PH. These compensations were downward in the advanced stages. Other factors may also impact NO/eNOS compensation. Although the role of NO/eNOS as biomarkers for PH in dogs remains equivocal, they may indicate compensatory consequences of cardiovascular alterations. Full article

Background: The number of senior chronic kidney disease (CKD) patients is steadily increasing worldwide. Falls are more frequent in this group than in the general population, and they are associated with a variety of complications ranging from minor (bruises) to severe (fracture, brain injury, or death). The significant burden of comorbidities, particularly cardiovascular disorders, impacts coordination. The aim of the study was to assess coordination disorders in CKD patients in the context of cardiovascular complications and vascular status. Methods: In this prospective study, 132 patients with CKD 2–5, including 40 (30%) hemodialysis patients, were enrolled. The short form physiological profile assessment (S-PPA) was used to assess coordination. Results: During a 2-year follow-up period, 49 individuals experienced 84 falls. The median S-PPA score (Z score) was 3.36. Based on this, we divided our cohort into two groups: a Z score of <3.36 and a Z score of ≥3.36. The groups with high scores (≥3.36) characterized by higher parameters of vessel stiffness, including AIx@75, augmentation pressure, and PWV, experienced considerably greater numbers of falls (41 vs. 8, p < 0.001), CV events (10 vs. 2, p < 0.05), and deaths (14 vs. 0, p < 0.001). Conclusions: Coordination impairments and the associated risk of falls in CKD patients are directly related to cardiovascular diseases and vascular conditions. Lower arterial compliance has been linked with the largest coordination disorder. Visual impairments, especially contrast sensitivity, are an independent risk factor for falls. 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

Background/Objectives: During cardiopulmonary resuscitation (CPR), patients must be checked for signs of return of spontaneous circulation (ROSC). Point-of-care ultrasound (POCUS) may be more reliable for detecting the ROSC. We investigated whether a POCUS pulse check algorithm could be used in compliance with the CPR guidelines. Methods: This was a prospective controlled and blinded multicentre manikin study involving staff from two tertiary clinical centres and their emergency medical services. A standard operating procedure for POCUS pulse checks during CPR was evaluated using a simulator in a team of four. The POCUS pulse checks were performed at the central artery following basic and advanced life support. The first pulse check was performed in the setting of pulseless electrical activity, and the second was performed in the presence of ROSC. The participants also completed a questionnaire. Results: A total of 444 pulse checks (244 manual/200 POCUS) were performed in 100 scenarios. The participants comprised physicians (34%), nurses (15%), non-physician emergency medical services personnel (37%), and other medical personnel (14%). The pulse checks took an average of 6.7 s (SD 3.9 s). Manual pulse checks (7.3 s) took longer than ultrasound pulse checks (6.1 s; p < 0.01), which were performed after a mean of 7.1 min (SD 1.7 min), during the fourth rhythm analysis in 93% of cases, and at the femoral artery in 62% of cases. They were rated as “easy” to perform by 77% and “useful” by 94%. Conclusions: POCUS pulse checks basically seem easy to implement and appear to be feasible during CPR. Full article

Background: The ketogenic diet has been successfully used in the last 100 years in the treatment of epilepsy and other neurological disorders. In recent decades, it gained wider application in the treatment of obesity, metabolic syndrome, and type 2 diabetes. However, there have been only a few studies on its use in children with obesity and associated metabolic disorders. Objectives: To determine the clinical and metabolic effects of a well-formulated low-carbohydrate (ketogenic) diet in children with obesity. Methods: One hundred children with obesity and metabolic disorders underwent initial anthropometric, laboratory, and ultrasound examinations. They were placed on a well-formulated ketogenic diet and monitored for 4 months. The 58 patients who completed the study underwent follow-up examinations to assess the effects of the diet on anthropometric, clinical, and laboratory markers of metabolic syndrome and insulin resistance, cardiovascular risk factors, and certain hormone levels. Compliance with the diet, common difficulties in adhering to it, side effects, and positive changes in the patients’ health were analyzed. Results: At the end of the study, the average weight loss for the entire group was 6.45 kg, with a reduction in BMI of 3.12 kg/m². Significant improvements were also observed in insulin resistance indicators, including fasting insulin levels, HOMA-IR index, QUICKI (p < 0.0001), and adiponectin (p = 0.04). The cases of hepatosteatosis decreased twofold, the number of patients with arterial hypertension was significantly reduced, as well as the number of children receiving antihypertensive therapy. Additionally, the number of patients meeting the criteria for metabolic syndrome decreased threefold. Conclusions: A well-formulated short-term ketogenic diet is effective in treating obesity, metabolic syndrome, and related comorbidities, and can be part of a comprehensive approach for these patients. Full article

Background/Objectives: Managing ventilatory strategies in patients with obesity under general anesthesia presents significant challenges due to obesity-related pathophysiological changes. Inverse ratio ventilation (IRV) has emerged as a potential strategy to optimize respiratory mechanics during laparoscopic surgery in this population. The primary outcomes were changes in respiratory mechanics, including peak inspiratory pressure (P_Peak), plateau pressure (P_Plat), mean airway pressure (P_Mean), and dynamic compliance (C_Dyn). Secondary outcomes included gas exchange parameters, hemodynamic measures, inflammatory cytokines, and postoperative complications. Methods: A systematic review and meta-analysis were conducted, searching PubMed, Scopus, EMBASE, and PMC Central. Only English-language randomized controlled trials (RCTs) evaluating the impact of IRV in adult surgical patients with obesity were included. The quality and certainty of evidence were assessed using the Risk of Bias 2 (RoB 2) tool and the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) framework, respectively. Results: Three RCTs including 172 patients met the inclusion criteria. Compared to conventional ventilation without prolonged inspiratory time or IRV, IRV significantly reduced P_Peak (MD [95%CI]: −3.15 [−3.88; −2.42] cmH₂O, p < 0.001) and P_Plat (MD [95%CI]: −3.13 [−3.80; −2.47] cmH₂O, p < 0.001) while increasing P_Mean (MD [95%CI]: 4.17 [3.11; 5.24] cmH₂O, p < 0.001) and C_Dyn (MD [95%CI]: 2.64 [0.95; 4.22] mL/cmH₂O, p = 0.002) during laparoscopy, without significantly affecting gas exchange. IRV significantly reduced mean arterial pressure (MD [95%CI]: −2.93 [−3.95; −1.91] mmHg, p < 0.001) and TNF-α levels (MD [95%CI]: −9.65 [−17.89; −1.40] pg/mL, p = 0.021). Conclusions: IRV optimizes intraoperative respiratory mechanics but has no significant impact on postoperative outcomes, necessitating further research to determine its clinical role. 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

Background: Optimizing fluid therapy is critical for maintaining hemodynamic stability in elderly patients undergoing major surgeries. Dynamic arterial elastance (Eadyn), defined as the ratio of pulse pressure variation (PPV) to stroke volume variation (SVV), has been proposed as a predictor of fluid responsiveness, especially in challenging conditions like prone-positioned spine surgery under general anesthesia. Methods: Hemodynamic parameters were measured before and after fluid loading with 500 mL of crystalloid solution. Patients were classified as responders or non-responders based on a ≥15% increase in mean arterial pressure (MAP) post-fluid administration. Predictive performance of these parameters was assessed using receiver operating characteristic (ROC) analysis. Results: Of the 37 patients, 15 were classified as responders and 22 as non-responders. Eadyn demonstrated poor predictive performance (AUC = 0.508). In contrast, SVV (AUC = 0.808), PPV (AUC = 0.738), and C (AUC = 0.741) exhibited moderate to high predictive ability. Responders exhibited significantly higher baseline SVV, PPV, and net arterial compliance compared to non-responders. Conclusions: Dynamic arterial elastance (Eadyn) showed limited predictive ability for fluid responsiveness in elderly patients undergoing spine surgery in the prone position. In contrast, stroke volume variation (SVV), pulse pressure variation (PPV), and net arterial compliance (C) demonstrated superior reliability, with SVV emerging as the most accurate predictor. Full article