Search Results (211)

Understanding the mechanical behavior of valve materials and the hemodynamic characteristics of blood flow is important for improving prosthetic heart valve design. In this study, a comprehensive computational investigation was conducted to evaluate the biomechanical and hemodynamic behavior of a three-dimensional tricuspid valve model constructed from reported prosthetic valve geometries. The structural response of the valve was evaluated using linear elastic, viscoelastic, and hyperelastic constitutive models for four different materials: pyrolytic carbon, polyurethane, porcine tissue, and bovine tissue. The results demonstrated clear material-dependent trends. Pyrolytic carbon exhibited negligible deformation (1.7166 × 10⁻⁸ m), confirming its rigid mechanical behavior, whereas biological tissues showed greater compliance, with the largest deformation observed for the bovine hyperelastic model (9.6837 × 10⁻⁵ m). Hyperelastic tissue models produced lower peak von Mises stresses (1.3951 × 10⁴–1.8603 × 10⁴ Pa) than the corresponding linear elastic tissue models (2.6842 × 10⁴–2.7017 × 10⁴ Pa), indicating improved stress redistribution under nonlinear deformation. Polyurethane showed intermediate mechanical behavior, with moderate deformation and lower stress under viscoelastic modeling than under the linear elastic assumption, suggesting its potential as a polymeric alternative to traditional valve materials. The Computational Fluid Dynamics (CFD) analysis of the rigid open valve geometry revealed a central velocity jet with a peak velocity of approximately 0.092 m/s, localized vortex formation with a maximum vorticity magnitude of about 177 s⁻¹ and a peak instantaneous wall shear stress of 1.32 Pa near the leaflet edges and valve opening. Overall, the results highlight the trade-off between rigidity, compliance, and durability among prosthetic valve materials and suggest that polyurethane may provide a balanced alternative for tricuspid valve replacement. Full article

Gla-rich protein (GRP), also known as UCMA, is a vitamin K-dependent protein that has emerged as an important regulator of pathological calcification and inflammation. Vascular calcification is a major complication of chronic kidney disease and cardiovascular disorders and is now recognized as an active and tightly regulated process rather than a passive accumulation of minerals. Increasing evidence indicates that GRP plays a protective role in mineral homeostasis through its strong calcium-binding capacity and its dependence on vitamin K-mediated gamma carboxylation. This work represents a comprehensive narrative review aimed at summarizing and critically discussing the current scientific knowledge on GRP. Available experimental and clinical data are analyzed with respect to gene expression, molecular regulation, vitamin K dependency, and underlying mechanisms of action. Particular emphasis is placed on the dual function of GRP in inhibiting ectopic calcification and modulating inflammatory responses. The evidence linking altered GRP levels or changes in its carboxylation status with chronic kidney disease, vascular calcification, calcific aortic valve disease, osteoarthritis, and tumor-associated microcalcifications is systematically examined. Current findings collectively support the concept that GRP is a multifunctional protein operating at the interface of mineral metabolism, inflammation, and tissue remodeling. Despite promising experimental data, important knowledge gaps remain, including the absence of standardized assays capable of distinguishing different GRP forms and the lack of longitudinal clinical studies evaluating its predictive value. This manuscript highlights the potential of GRP as a biomarker of disturbed mineral homeostasis and cardiovascular risk, while emphasizing the need for further research to clarify its precise biological functions and clinical relevance. Full article

Background: Lipoprotein(a) [Lp(a)] is an inherited cardiovascular risk factor, but its relationship with coronary anatomical complexity, plaque phenotype, and outcomes after percutaneous coronary intervention (PCI) remains incompletely defined. Methods: We conducted a systematic review and meta-analysis of studies evaluating the association between circulating Lp(a) levels and coronary disease characteristics, post-PCI clinical outcomes, stent-related adverse outcomes, and aortic valve disease. Results: Twenty-six studies were included. Elevated Lp(a) levels were associated with greater coronary anatomical complexity and a higher risk of major adverse cardiovascular events after PCI (HR 1.4, 95% CI 1.2–1.7). The strongest associations were observed for stent-related adverse outcomes, including restenosis (OR 3.23, 95% CI 2.2–4.8) and target vessel revascularization (OR 2.6, 95% CI 1.6–4.4). Higher Lp(a) levels were also associated with vulnerable plaque features and aortic valve calcification. Conclusions: Elevated Lp(a) is associated with greater coronary disease complexity and adverse outcomes after PCI. Elevated Lp(a) may represent a biological marker identifying high-risk patients and providing additional insight for personalized risk stratification and procedural decision-making in patients undergoing PCI. Full article

Solution electrospinning (SES) and melt electrowriting (MEW) are complementary fiber-based fabrication platforms extensively investigated in tissue engineering. SES generates fibers typically ranging from the nanometer to the low-micrometer scale, producing fibrous networks that mimic the native extracellular matrix (ECM) and support key cellular functions. MEW, by contrast, operates solvent-free and enables precise, layer-by-layer deposition of microfibers with well-controlled geometry, conferring the mechanical integrity and open-pore architecture that SES constructs inherently lack. Despite growing interest, the body of peer-reviewed literature reporting original hybrid SES–MEW fabrication and biological outcome data remains limited, with no comprehensive cross-tissue synthesis available to date. This narrative review examines the current state of SES–MEW hybrid strategies across five tissue engineering targets selected for their clinical relevance: skin, vascular grafts, bone, cartilage, cardiac valves, and skeletal muscle. For each application, the architectural rationale, the fabrication approach, and the in vitro and in vivo biological outcomes are discussed in an integrated manner, with attention to how the spatial organization of nano- and microfibers translates into tissue-specific functional responses. A comparative analysis across tissue types highlights both the versatility of hybrid constructs and their persistent limitations, including suture retention values that remain below clinically accepted thresholds in vascular applications, incomplete cellular infiltration through dense nanofibrous layers, and the absence of validated, reproducible scale-up protocols compatible with clinical-grade manufacturing. The review concludes by identifying the most critical open questions in the field, encompassing process standardization, regulatory classification, and the emerging role of machine learning in closed-loop MEW process optimization. This work aims to provide an evidence-based perspective on the current state of hybrid SES–MEW scaffold engineering and the key translational gaps limiting clinical application. Full article

Sutureless aortic bioprostheses have become an established alternative for surgical aortic valve replacement, particularly in elderly and high-risk patients. The Perceval (Livanova) valve, the most widely studied sutureless device, offers favorable hemodynamic performance and reduced operative times but introduces specific challenges when prosthetic valve endocarditis (PVE) occurs. Although the incidence of Perceval PVE is low and comparable to that of conventional bioprostheses, this complication is associated with substantial morbidity and mortality. Diagnosis is often complex due to acoustic shadowing on echocardiography, making multimodality imaging with transesophageal echocardiography, cardiac computed tomography, and [18F]-FDG PET/CT essential. Microbiological profiles resemble those of other biological prostheses, but perivalvular extension and early mechanical instability are frequent. Management follows general PVE principles but often requires early surgical intervention because of the valve’s reliance on radial fixation. This review summarizes current evidence on epidemiology, microbiology, diagnostic strategies, treatment, and prognosis of endocarditis involving the Perceval valve, and identifies areas for future research. Full article

Background: Frailty strongly influences outcomes after transcatheter aortic valve implantation (TAVI), but conventional risk models insufficiently capture functional and cognitive vulnerability. We compared conventional surgical risk scores with multidimensional frailty assessment and a biological score. Methods: This observational registry included 528 consecutive patients with severe symptomatic aortic stenosis undergoing TAVI between January 2019 and November 2024. Frailty was assessed using the Essential Frailty Toolset (EFT), Katz Index, and cognitive screening, alongside French Aortic National CoreValve and Edwards 2 (FRANCE-2) and Age, Creatinine, and Ejection Fraction (ACEF) scores. HALP was calculated as (haemoglobin × albumin × lymphocytes) ÷ platelets. Primary endpoints were 30-day, 6-month, and 1-year all-cause mortality. Secondary outcomes included non-fatal major adverse cardiovascular events (MACE), complications, and quality-of-life improvement. Results: One-year mortality was 12.7%. EFT and Katz Index showed the strongest discrimination for 1-year mortality (AUC 0.72 and 0.75), outperforming EuroSCORE II and STS-PROM (AUC 0.66 and 0.68). After adjustment, EFT (HR 1.91, 95% CI 1.47–2.48), Katz Index (HR 0.57, 95% CI 0.47–0.70, and cognitive impairment (HR 2.24, 95% CI 1.34–3.75) independently predicted 1-year mortality. HALP was not associated with outcomes. FRANCE-2 independently predicted 1-year MACE (HR 1.24, p = 0.019). Conclusions: Functional frailty and cognitive impairment add prognostic value beyond conventional comparator models, whereas HALP does not. Brief functional and cognitive screening may help Heart Teams identify patients who need closer peri-procedural optimisation, rehabilitation planning, and discharge support rather than relying on surgical risk scores alone. Full article

Valvular heart disease remains a major global health burden, with currently available prosthetic heart valves failing to fully reproduce the adaptive, regenerative, and long-term functional properties of native valves. Tissue-engineered heart valves (TEHVs) have emerged as a promising alternative, aiming to develop living valve replacements capable of growth, remodeling, and physiological integration. However, despite substantial progress, the clinical translation of TEHVs remains limited, indicating the need for design strategies that go beyond material selection toward functionally mature constructs. This review presents recent advances in TEHV development from a biomimetic perspective, using native heart valves as a biological reference characterized by hierarchical structure, anisotropic mechanical behavior, mechanoresponsive cell populations, immune regulation, and temporally coordinated remodeling. We integrate current understanding of valve biology and mechanobiology with advances in scaffold materials and architecture, bioactive functionalization, biomechanical conditioning, and emerging fabrication and monitoring technologies. We discuss how biomimetic scaffold designs aim to replicate native extracellular matrix organization and nonlinear mechanics, how biological cues are used to regulate thrombosis, immune response, and cell recruitment, and how dynamic bioreactor systems support functional tissue maturation through controlled mechanical stimulation. Finally, key challenges for clinical translation are highlighted, and future directions are outlined, emphasizing integrated and biomimetically informed design approaches. Overall, this review aims to define guiding principles that may accelerate the development of durable, regenerative, and clinically translatable tissue-engineered heart valves. We argue that successful TEHV translation requires synchronized control of scaffold anisotropy, immune modulation, and mechanical conditioning rather than incremental material optimization. Full article

Introduction: The global disease burden of aortic valve disease is already substantial and is projected to rise significantly in the coming decades. Aortic valve replacement (AVR) with a biological prosthesis has become highly popular and commonly used. This study aims to assess long-term outcomes after biological AVR with regard to structural and non-structural deterioration. Methods: In this single-centre retrospective study, 918 patients undergoing surgical AVR with a biological prosthesis at the University Hospital Frankfurt from January 2006 to July 2009 were included. The primary endpoints were freedom from reoperation and from structural and non-structural deterioration, and the secondary was long-term survival. Follow-up was completed in 95.6% with a median of 7.6 years, accounting 6610 patient-years. The mean age was 74.9 years and a median EuroSCORE II (range) was 3.34 (0.77–62.4). Twenty-two percent of surgeries were either emergent or urgent. Many patients had concomitant surgery, while coronary artery bypass grafting in 45.3% of patients was the most common. Three prosthetic valve models were used in our patient population: Carpentier Edwards Perimount (CEP) Model 2900, Model 3000 and Medtronic Mosaic (MM). Results: Reoperation occurred in 36 patients (3.9%) due to endocarditis (2.0%), aortic root aneurysm (0.1%), isolated or combined aortic stenosis or aortic regurgitation (1.9%). Freedom from reoperation at 5, 10 and 15 years was 97 ± 0.6%, 95.6 ± 0.8% and 90.3 ± 2.3%, respectively. Freedom from major stroke at 5, 10 and 15 years was 97.9 ± 0.0%, 96.4 ± 0.8%, and 96.1 ± 0.08%, and freedom from major bleeding event at 5, 10 and 15 years was 98.5 ± 0.4%, 95.7 ± 0.9% and 92.7 ± 2.2%, respectively. A subgroup analysis of the Carpentier Edwards (CEP) valves and the Medtronic Mosaic (MM) valves showed no significant differences regarding the primary endpoints. The overall survival at 5, 10 and 15 years was 67 ± 1.7%, 39.8 ± 1.8%, and 15.1 ± 2.2% respectively. The Kaplan–Meier survival estimator was 96 ± 2.2 months. Conclusion: This study showed a good long-term survival of surgical AVR with biological prostheses in relatively high-risk and elderly patient population. All biological prosthetic valves showed good long-term durability with low levels of complications and reoperations. The different models did not show any significant differences. Surgical AVR remains a valuable therapeutic option even though transcatheter aortic valve implantation has been greatly expanded since its introduction. Full article

A newly commercialized single-row multi-fan autonomous unmanned ground vehicle (UGV) sprayer, for use in trellised tree fruit crops, was tested to better understand air and spray patterns prior to wide-scale adoption in the modern apple orchard systems typical to Washington State. This sprayer was equipped with five brown and yellow Albuz ATR80 nozzles per fan (QM-420, Croplands Quantum). The fans were installed in a Q8 configuration, with eight fans (four on each side) staggered near the front and back as a stack to increase vertical span. Air velocity and spray delivery patterns of the commercialized sprayer unit were assessed in laboratory using a customized smart spray analytical system. Previous field trails of this sprayer unit revealed a hardware issue with electric proportional valve controls in fan-nozzle assembly, resulting in uneven spray deposition across V-trellised canopy. Post issue resolution, the sprayer characterization data showed an average Symmetry of 91%, and 84% for air velocity and spray volume delivery on either side. An average Uniformity of 57% and 48%, respectively was recorded for pertinent sprayer attributes across the spray height. Overall, after optimization, the UGV sprayer is suitable for efficient agrochemical application in modern orchard systems. Further evaluation of labor savings, biological efficacy gains from autonomous operation, and a full economic analysis would better inform grower adoption. Commercial viability of this UGV sprayer could also be improved by added features such as variable-rate application enabled by real-time crop sensing or task-map integration. Full article

Polyurethane-based implantable devices (PUIDs) delivered via catheter are increasingly used in structural heart interventions; however, limited in vivo data exist regarding their long-term biostability and biological safety. This study evaluated a balloon-shaped implant made of Pellethane^®, a polyether-based polyurethane, designed as a three-dimensional intracardiac spacer and deployed via percutaneous femoral vein access. The device was chronically positioned adjacent to the tricuspid valve annulus in seven pigs for 24 weeks. Explanted devices and surrounding tissues were evaluated through material characterization (SEM, GPC, FT-IR, and ¹H-NMR) and histological analysis. SEM and FT-IR confirmed preserved surface morphology and chemical bonds, GPC showed stable molecular weight, and ¹H-NMR revealed intact urethane and ether linkages. Materials characterization revealed no evidence of hydrolytic or oxidative degradation, indicating structural stability of the devices. Histological analysis showed stable device positioning with minimal thrombosis or inflammatory response. Biocompatibility was confirmed via ISO 10993-1:2018 Standard (International Organization for Standardization (ISO): Geneva, Switzerland, 2018), and extractable substances were evaluated under exhaustive extraction conditions specified by ISO 10993-18:2020 (International Organization for Standardization (ISO): Geneva, Switzerland, 2020), with no toxicologically significant findings. These findings support the long-term biostability and biological safety of the PUIDs in dynamic cardiac environments, informing future design criteria for catheter-delivered cardiovascular devices. Full article

Biological, biomimetic, and engineering systems make extensive use of hydraulic asymmetries to control flow inside tubular structures. Examples span physiological valves, the guided transport observed in shark intestines, and passive devices such as Tesla valves. Here we investigate the mechanisms that generate these asymmetries using the notion of diodicity, defined as the ratio between pressure drops required to drive the same flow in opposite directions. We first focus on 2D geometries, which allow us to identify and study the main contributions to hydraulic asymmetry: channel geometry and internal obstacles embedded within a channel with rigid walls. By considering both rigid and deformable obstacles, we model channels that always remain open in both directions and channels that can be completely blocked by valve-like structures. We then extend the analysis to 3D geometries, again considering rigid and elastic cases. As a general trend, we find that geometry alone establishes a baseline diodicity, while higher dimensionality and structural reconfiguration consistently amplify the effect. Full article

Background: Cardiovascular implications in systemic lupus erythematosus (SLE) are common and varied, including impacts on the pericardium, myocardium, valves, coronary arteries, and conduction system; all of these could be potential substrates or triggers of cardiac arrhythmias by interfering with disease severity and specific medication. Therefore, this narrative review aimed to assess the cardiac involvement in SLE underlying, mainly, cardiac arrhythmias. Methods: We analyzed studies, published between 2015 and 2025 on PubMed, which explore cardiovascular involvement with a focus on arrhythmias in SLE from the perspectives of epidemiology, underlying mechanisms, diagnostic techniques, and the impact of standard and biologic therapies. Results: The cardiac manifestation of LES (lupus pericarditis, lupus myocarditis, Libman–Sacks endocarditis, coronary artery disease, coronary vasculitis or myocardial fibrosis) represents a substrate for arrhythmia risk. These substrates, in association with other arrhythmias mechanisms considered as triggers or conduction abnormalities, determined arrhythmogenic conditions in these patients. In addition to structural heart disease, arrhythmias in SLE are caused by ongoing inflammation, immune system irregularities, microvascular problems, autonomic imbalance, oxidative stress, and side effects from treatments. Despite this complex background, arrhythmias are often overlooked and not routinely investigated in SLE care. Data that show how disease-modifying drugs may affect arrhythmias are limited and inconsistent, highlighting significant gaps in knowledge. Cardiac arrhythmias are a significant but, as yet, insufficiently underrecognized aspect of SLE, with serious implications for prognosis. Conclusions: Systemic lupus erythematosus causes cardiovascular involvement that is associated with arrhythmias through various and complexes mechanisms, mainly related to direct cardiovascular structural damage, systemic inflammation or specific therapies. Data on arrhythmias secondary to cardiovascular damage in patients with SLE in the literature are limited. Therefore, early detection of electrical issues, regular cardiovascular evaluation in high-risk patients, and careful management of treatment effects are vital. A coordinated, multidisciplinary cardio-rheumatology approach is essential to improving arrhythmia detection, tailoring treatments, and ultimately decreasing cardiovascular complications and deaths in SLE patients. Full article

Widespread in coastal environments, artificial light at night (ALAN) is suspected to disrupt organisms’ biological rhythms by altering natural light cycles and thus constitutes a growing threat to these ecosystems. This study evaluates the effects of ALAN exposure at low and realistic intensity (~1 lx) on a coastal keystone species, the oyster Crassostrea gigas. The results reveal that ALAN significantly impairs the expression of core circadian clock genes (CgClock and CgBmal1) as well as the valve opening behavior, affecting rhythmic characteristics such as its robustness and daily profile. At the same time, ALAN leads to a decrease in daily shell growth and to a disruption of the gill microbiota, associated with an obliterated day/night difference in microbial alpha diversity. A direct correlation between a decrease in daily rhythm robustness, limitation of shell growth, and some microbial strands is shown, suggesting that biological rhythm disruption caused by ALAN might have harmful physiological consequences in oysters. Full article

Inspired by the Tesla valve, the island-type fishway is a novel design whose biological performance remains unelucidated. This study integrated hydraulic experiments, CFD modeling, and 3D computer vision to investigate the passage performance and swimming behavior of juvenile silver carp (Hypophthalmichthys molitrix). The results confirmed high biological feasibility, with upstream success rates exceeding 70%. The island and arc-baffle configuration create a heterogeneous flow field with an S-shaped main flow and low-velocity zones; each island unit contributes 8.9% to total energy dissipation. Critically, fish utilize a multi-dimensional navigation strategy to avoid high-velocity cores: temporally adopting an intermittent “rest-burst” pattern for energetic recovery; horizontally following an “Ω”-shaped bypass trajectory; and vertically preferring the bottom boundary layer. Passage failure was primarily linked to suboptimal path selection near the high-velocity main flow. These findings demonstrate that fishway effectiveness depends less on bulk hydraulic parameters and more on the spatial connectivity of hydraulic refugia aligning with fish behavioral traits. This study provides a scientific basis for optimizing eco-friendly hydraulic structures. Full article

Background: Prosthesis patient mismatch (PPM) is associated with poor outcomes in literature. Prevention of mismatch is crucial in aortic valve replacement, yet there is no current consensus on preventative strategies. Objectives: This study introduces a novel clinical framework, nomenclature, and algorithm for contemporary Heart Team practice, providing a systematic approach for a tailored surgical strategy to anticipate and prevent mismatch. Methods: This was a single-center observational study performing a descriptive analysis of an evolving practice on 100 consecutive patients operated for aortic valve stenosis between 2020 and 2024. A step-by-step No-Mismatch algorithm was designed for the Heart Team to triage, discuss, and decide the surgical strategy prior to the procedure, identifying patients at risk of mismatch, and guiding the surgeon’s plan to prevent PPM and consider a Lifetime Valve Strategy. Results: The algorithm identified 26% of patients at risk of mismatch requiring a No-Mismatch strategy, and 20% at risk of small valve implantation requiring a Lifetime Valve Strategy. This cohort included 51 urgent cases. Valve pathology included 35% congenital, 59% degenerative, 1% rheumatic, and 5% redo operations. Valve implant type: 82% biological, including 29% rapid deployment valve (RDV), and 18% mechanical; 20% of patients required aortic root enlargements (AREs). Pre-, intra-, and post-operative data are presented. Mortality occurred at 1%. All degrees of mismatch were prevented. Conclusions: The surgeon was able to predict mismatch and elected either ARE, RDV, or a mechanical valve as required. Patient selection and a No-Mismatch Heart Team approach are essential to provide a tailored strategy for aortic valve interventions. Full article