Search Results (6,367)

Background/Objectives: Acute kidney injury (AKI) remains a significant complication following cardiac surgery, associated with increased morbidity and mortality. The early detection of AKI is limited by the cost, availability, and unclear clinical utility of the current biomarkers. This study aimed to evaluate the red cell distribution width (RDW) on ICU admission as a predictor of postoperative AKI. Methods: We conducted a retrospective analysis of adult patients undergoing isolated coronary artery bypass grafting (CABG) or combined CABG and aortic valve surgery at a tertiary cardiac surgery centre (University Hospital of Siena, Italy) between January 2015 and December 2020. AKI was defined according to the KDIGO criteria. The RDW was measured preoperatively (T0), at ICU admission (T1), and at 24 (T2) and 48 h (T3) postoperatively. Temporal RDW changes (ΔRDW) were also calculated. Multivariate logistic regression identified independent predictors of AKI, and receiver operating characteristic (ROC) analysis evaluated the predictive accuracy. Results: A total of 456 patients were included, with an overall AKI incidence of 31%. Patients developing AKI exhibited significantly higher RDW at all measured time points, especially at ICU admission. Multivariate analysis identified age, RDW (OR 1.19, 95% CI: 1.03–1.37, p = 0.016) and serum creatinine at ICU admission, and elevated lactate at T2 as independent AKI predictors. In subgroup analyses, RDW at ICU admission remained significantly associated with AKI in patients who were not transfused, but not in patients who were. Conclusions: In this study, a high RDW at ICU admission represented an early postoperative marker independently associated with AKI after cardiac surgery, particularly in patients who did not receive transfusion. Full article

An improved optimizer based on projection-iterative methods (IPIMO) is proposed to address the optimal configuration problem of multi-type energy storage systems (MT-ESS), with the objective of achieving synergistic minimization of comprehensive costs, including both investment and operational expenditures. A comprehensive energy system model is established, integrating photovoltaic power, wind power, and six typical energy storage technologies—lithium-ion battery, flywheel energy storage, supercapacitors, valve-regulated lead-acid battery, compressed air energy storage, and redox flow battery. Four typical operational scenarios are designed to validate the adaptability and robustness of the algorithm. A systematic evaluation of IPIMO’s comprehensive performance is conducted by comparing it with the weighted average method (WA), the single-energy storage optimization method (SEO), the projection-iterative-methods-based optimizer algorithm (PIMO), and the genetic algorithm (GA). Simulation results demonstrate that IPIMO exhibits superior convergence performance, achieving stable convergence rapidly and significantly outperforming PIMO and GA. Moreover, IPIMO achieves the lowest total cost across all four scenarios, with an average of $46,837, representing reductions of 6.54% compared to the benchmark weighted average method and 11.8% compared to the SEO. Additionally, IPIMO adaptively adjusts the allocation ratios of energy storage types based on scenario characteristics, prioritizing energy-type storage in stable scenarios while increasing the proportion of fast-response storage to 49.1% in fluctuating scenarios, thereby demonstrating its strong scenario adaptability. Full article

Atrioventricular valves prevent the backward flow of blood from the ventricles to the atria and are essential for the efficient pumping of blood throughout the body. Errors in development can lead to congenital atrioventricular valve disease. Atrioventricular valve formation is a multi-step process that involves endocardial cushion formation, valve progenitor cell proliferation, valve sinus formation, valve elongation, and extracellular matrix remodeling. Increasing evidence suggests that hemodynamic cues are required across multiple steps. Here, we compare atrioventricular valve formation in different in vivo models and review how biomechanical forces regulate atrioventricular valve formation. Full article

External leakage from valve stem packings is a critical safety and reliability issue in high-pressure hydrogen systems. This work aims to quantify how packing geometry and polymer selection influence stem sealing in a PN650 needle valve (316L body and stem). Two geometries were compared: a conical V-ring (chevron style) stack and a flat three-disc stack. Two polymer material sets were assessed: Vespel^® polyimide (SP-1/SP-21) and a glass-filled PTFE sealing element combined with a virgin PEEK back-up ring. Four assemblies (one per geometry/material combination) were first screened by hydrostatic pressure hold testing up to 1500 bar and by helium mass spectrometer leak measurements under vacuum. All assemblies sustained the hydrostatic overpressure hold with negligible decay. Vacuum helium screening produced leak rates between 3.7 × 10⁻¹⁰ and 9.5 × 10⁻¹⁰ mbar·l·s⁻¹, with the conical V-ring geometry consistently outperforming the disc stack. A more demanding helium test at 700 bar with external vacuum yielded leak rates of 3.6–3.7 × 10⁻⁸ mbar·l·s⁻¹, for conical assemblies. Based on the screening results and practical industrial considerations, the PTFE/PEEK conical configuration was selected for endurance testing and completed 2500 open/close cycles in 650 bar hydrogen without gland readjustment. Post-cycling checks confirmed continued tightness, including a qualitative helium pressure hold result near 700 bar and 0 bubbles in 10 min in the seat tightness test. Microscopy/EDX revealed limited wear with minor metallic transfer. The proposed multi-stage workflow provides a pragmatic route for the early qualification of stem packings for high-pressure hydrogen valves. Full article

Background and Objectives: Transcatheter aortic valve replacement (TAVR) in large aortic annuli poses challenges due to limited valve-size options and increased complication risks. The aim is to evaluate the safety and performance of XL sizes (30.5 mm and 32 mm) of the Myval transcatheter heart valve (THV) for treating patients with severe aortic stenosis and large aortic annuli. Material and Methods: This retrospective observational study included consecutive patients undergoing TAVR with XL sizes of the Myval THV between December 2023 and December 2024 at a single centre. During this period, 146 TAVI procedures were performed, of which 15 patients (10.3%) with large aortic annuli (mean systolic annular area 786.5 ± 48.2 mm²) received XL valves and were included in the present analysis. Patients were followed up at discharge, 3–6 months, and 1 year. Patient evaluation included echocardiography and clinical assessments following the Valve Academic Research Consortium-3 criteria. Results: All patients were male, with a mean age of 79.1 ± 5.9 years. Technical success was achieved in 100% of cases. At discharge, none of the patients had moderate or greater paravalvular leakage (PVL); 11 patients had no PVL, while 1 had trace and 3 had mild PVL. The mean effective orifice area (EOA) improved from 0.75 ± 0.15 cm² at baseline to 2.31 ± 0.21 cm² at discharge (p < 0.0001). At the 12-month follow-up, the mean EOA was 2.4 ± 0.3 cm², and no moderate or severe PVL or major adverse clinical outcomes were observed. One patient required a permanent pacemaker implantation due to an atrioventricular block. Conclusions: The XL sizes of Myval THV showed both safety and efficacy in patients with large aortic annuli, demonstrating acceptable hemodynamic performance and low complication rates. However, large-scale studies with longer follow-ups are needed to validate these findings in diverse populations. Full article

Degenerative mitral stenosis (MS) secondary to extensive mitral annular calcification (MAC) represents a growing clinical challenge in an aging population. These patients are often elderly, frail, and harbor a significant burden of comorbidities, rendering conventional mitral valve surgery prohibitively high-risk. While transcatheter mitral valve replacement (TMVR) has emerged as a potential alternative, the current evidence is only derived from single-arm observational registries. Therefore, the transition toward randomized controlled trials to define optimal patient selection and long-term prosthetic durability is necessary. This review examines the current landscape of TMVR for degenerative MS, focusing on the role of multimodal pre-procedural planning, procedural technique, and prevention of the principal complications. The integration of echocardiography and multi-slice computed tomography (MSCT) is essential for evaluating anatomical feasibility, particularly in predicting neo left ventricle outflow tract (neo-LVOT) obstruction, the primary determinant of procedural mortality. However, it is limited due to the absence of standardized protocol. We are showing the outcomes of off-label balloon-expandable aortic prostheses and dedicated TMVR system, which are the only two devices which data in patients with MS are available. Despite high technical success rates in specialized centers, complications, including paravalvular leak, valve thrombosis, and device migration, remain more prevalent than in aortic interventions. We present some tips and tricks to prevent and manage adverse events. TMVR represents a transformative frontier for inoperable patients with severe MAC. However, its routine clinical adoption requires further refinement of dedicated technologies and standardized imaging protocols to improve safety and bridge the gap between palliative medical therapy and definitive intervention. Full article

Background/Objectives: Acute hemodynamic collapse is a rare but deadly complication of transcatheter aortic valve replacement (TAVR) that can require temporary mechanical circulatory support (tMCS). Using a statewide collaborative, we conducted a focused analysis on the incidence and outcomes associated with the use of tMCS during TAVR as hemodynamic rescue. Methods: We identified adult patients who underwent TAVR between September 2012 and September 2024 within the statewide collaborative and stratified them based on if tMCS was needed. Baseline patient characteristics and risk factors associated with tMCS use were analyzed as well as the impact of tMCS on outcomes. Results: We identified 7735 patients who underwent TAVR. A total of 44 (0.57%) patients required tMCS. Patients requiring tMCS were more likely to have histories that included diabetes, concurrent mitral regurgitation, prior MI, or NYHA class III or IV. These patients also experienced more emergent procedures and were more likely to require inotropic support. Patients experienced significantly worse outcomes following tMCS rescue during TAVR, with 18% requiring conversion to surgical approach (vs. 1%, p < 0.001) and 37% of tMCS patients experiencing cardiac arrest, compared to 1% of those who did not need tMCS (p < 0.001). Thirty-day mortality was worse for patients requiring tMCS (p < 0.001). MCS usage was independently associated with the need for further procedures. Conclusions: Unplanned, emergent tMCS during TAVR as hemodynamic rescue represents significant risk of complications and should be utilized judiciously in cases of acute hemodynamic collapse. Full article

Background/Objectives: Impella support is increasingly utilized as a crucial bridge to durable left ventricular assist device (LVAD) in patients with refractory cardiogenic shock. However, the transvalvular path of the Impella catheter raises concerns regarding mechanical trauma, potentially precipitating or accelerating aortic regurgitation (AR). We aimed to characterize the complete longitudinal trajectory of AR following Impella bridge-to-LVAD and to determine its association with clinical and hemodynamic sequelae. Methods: We conducted a single-center retrospective cohort study including all patients bridged from Impella to durable LVAD between 2013 and 2024 (n = 19). At Impella initiation, all patients met the retrospective SCAI shock stage D or worse criteria. At LVAD implantation, all patients were classified as INTERMACS 1–2 (INTERMACS 2, n = 13). The Impella models were 5.0 in 11 (axillary access), 2.5 in 5 (femoral access), and CP in 3 (femoral access); no periprocedural Impella complications were recorded. The implanted LVAD systems were HeartMate II (n = 7), HVAD (n = 3), and HeartMate III (n = 9). Patients undergoing concomitant aortic valve intervention were excluded. Transthoracic/TEE echocardiography was performed at prespecified time points (pre-Impella, pre-LVAD, post-LVAD discharge, 12 months, and 24 months) with standardized aortic regurgitation (AR) grading. Right ventricular (RV) function was assessed qualitatively when quantitative indices (TAPSE) were unavailable. Primary endpoints were new or progressive AR and AR severity at LVAD implantation. Secondary endpoints included survival, renal dysfunction, biomarkers, and rehospitalization. Univariate analyses were used to compare outcomes according to AR severity. Results: Nineteen patients (68% male, median age 57 years, IQR 47–60) underwent Impella support for 13.3 ± 9.9 days before HeartMate 3 (84%) or HVAD (16%) implantation. All patients had competent aortic valves (grade 0 AR) at the time of LVAD implantation. AR ≥ mild developed in 9/18 (50%) at discharge, 12/15 (80%) at 12 months, and 13/15 (87%) at 24 months, and 8/15 (53%) progressed to ≥ moderate AR by 24 months. Patients with moderate-to-severe AR had higher NT-proBNP levels at 12 months (median 6318 vs. 2336 pg/mL, p = 0.137). Thirty-day and 24-month survival rates were 95% and 79%, respectively. Conclusions: Aortic regurgitation frequently develops or progresses from the pre-LVAD period to follow-up in patients bridged from Impella to durable LVAD. Although limited by a small sample size and incomplete quantitative RV metrics, these observations support structured echocardiographic surveillance after Impella use and management strategies—routine valve inspection at LVAD implantation and post-LVAD speed/blood pressure targets that encourage aortic valve opening—to mitigate the risk and clinical impact of aortic regurgitation. Full article

Maritime decarbonization has shifted from a long-term aspiration to an engineering and systems-integrated problem under near-term compliance pressure. International regulatory bodies, governments, and a wide array of private-sector coalitions will tighten greenhouse-gas fuel-emission standards from 2028, translating climate targets into enforceable cost signals and accelerating interest in alternative-fuel and retrofit pathways. This review synthesizes the state of the art (SoA) of maritime decarbonization by mapping where technological bottlenecks concentrate along the well-to-wake (WtW) value chain for the main candidate pathways: biofuels, LNG/bio-LNG, hydrogen, ammonia, e-methanol, and electrification, and by benchmarking them side-by-side using a unified framework designed to compare their realizable well-to-wake GHG-reduction potential under maritime operating constraints. Building on that comparative lens, this work aims to connect pathway readiness to the near-term market and regulatory reality, while the alternative-fuel-capable fleet is projected to expand rapidly, creating a structural capability vs. supply gap, in which, for example, ship readiness can outpace low-GHG fuel availability and bunkering rollout. The merged evidence indicates that near-term abatement will be dominated by scalable drop-in biofuels, whereas deep-sea options (ammonia/hydrogen and e-fuels) remain gated by upstream low-GHG production, port infrastructure, and safety/regulatory maturation. Nevertheless, mid-term deployment of low-GHG fuels can act as a system “relief valve”, reducing infrastructure lock-in and accelerating emissions reductions while zero-carbon fuel supply chains scale up. Full article

Background/Objectives: Ascending thoracic aortic aneurysms (aTAAs) pose a high risk of dissection and rupture. Though more prevalent in males, females may experience worse outcomes. Growth rate is considered a part of risk assessment, yet data in non-syndromic females without valve abnormalities remain limited. This study aims to assess whether aTAA growth differs between non-syndromic females and males with normal aortic valve morphology. Methods: The systematic review followed the PRISMA 2020 guideline. The final search was completed in April 2025, with guidance from a certified librarian. Included studies were RCTs or observational studies of non-syndromic adults with aTAA reporting sex-specific data and included ≥10 females. Prior dissection, valve replacement, or surgery were excluded. In addition to the original search, 11 articles were identified as likely to contain sex-specific data, and the corresponding authors were contacted. The protocol is registered in PROSPERO (CRD420251025890). Meta-analysis was not performed due to high heterogeneity and limited study numbers. Results: Of 2629 identified studies, 73 studies were screened in full-text, and only three met the inclusion criteria. The most common exclusion reason was lack of appropriately sex-stratified data. Two authors out of the 11 contacted replied with additional datasets, resulting in a total of five studies being included. Of the five included studies, three found faster growth rates in females. Reported growth rates in females varied notably, ranging from −0.7–1.74 mm/year. Conclusions: Evidence on sex differences in aTAA growth among non-syndromic patients with normal aortic valves remains inconclusive. Three of the five studies reported faster growth in females. Standardization in future research is needed. Full article

To enhance the performance of high-speed solenoids (HSSs) in control systems, two improved structural designs incorporating a permanent magnet (PM) and an annular flange (AF) are proposed based on the parallel magnetic circuit principle. Their static electromagnetism performances were thoroughly investigated by the finite element method. Furthermore, multi-objective optimization combined with the response surface method and NSGA-II was carried out. The results indicate that the electromagnetic energy conversion efficiency and electromagnetic force of HSSs can be promoted by applying a PM and an AF: for the first improvement design just employing a PM, increasing the PM height improves energy conversion efficiency and mitigates magnetic saturation within the main pole, and for the second improvement design employing both a PM and an AF, the electromagnetic energy conversion efficiency and electromagnetic force of HSS can be further promoted. In the end, based on the Pareto optimal solution set, the optimized design increases the net electromagnetic force by 18.8% and reduces the peak current by 18.8%. This is the result of applying the optimization scheme, which is beneficial for increasing the dynamic response speed of the HSS valve and reduce its energy loss. Full article

The present study demonstrates a step-by-step method for optimizing the outflow valve geometry and maximizing thrust generation. In this system, the skin-mounted OutFlow Valve (OFV) acts as a convergent–divergent nozzle and, as such, the De Laval nozzle equations are considered as guidance for the shape optimization. The performance of the skin-mounted flapped OFV optimized designs is assessed with a combination of analytical equations and Computational Fluid Dynamics (CFD) methods. The three-dimensional Reynolds-Averaged Navier–Stokes (RANS) yield reliable thrust recovery estimates and reveal key aspects of the aerodynamic flow behaviour through the valve, highlighting the interaction between the skin-mounted flapped OFV components. The results compare well with the analytical approach, providing a basis upon which a skin-mounted flapped OFV can be tailored for a specific mission. Full article

Calcific aortic valve disease (CAVD) is an active pathological process driven by complex cellular and molecular mechanisms rather than passive aging. The disease is characterized by endothelial dysfunction, lipid infiltration, inflammation, extracellular matrix remodeling, and osteogenic differentiation of valvular interstitial cells, ultimately leading to hydroxyapatite deposition and progressive valve calcification. Key signaling pathways, including Notch, Wnt/β-catenin, BMP2, and TGF-β, play critical roles in osteogenic reprogramming, while inflammatory cytokines such as IL-6, IL-1β, and TNF-α contribute to a pro-calcific microenvironment. To summarize current knowledge on CAVD pathophysiology and emerging therapeutic strategies, relevant preclinical studies were identified through searches of PubMed, and clinical trials were identified through ClinicalTrials.gov. Evidence indicates that extracellular matrix remodeling, fibrosis, and dysregulated phosphate metabolism, particularly involving TNAP and DPP-4, further accelerate disease progression. Despite advances in understanding disease mechanisms, effective pharmacological therapies remain limited, with the current treatment largely restricted to valve replacement. Emerging therapeutic approaches targeting molecular pathways, including enzyme inhibition, RNA-based therapeutics, and advanced drug delivery systems, may offer promising strategies for disease modification. A deeper understanding of CAVD pathophysiology may facilitate the development of targeted therapies to delay or prevent disease progression. Full article

Background/Objectives: Chronic venous disease (CVD) is a prevalent condition marked by valve dysfunction and increased pressure in lower limb veins. The trans-nodal veins in the inguinal region and Scarpa triangle, which connect the superficial and deep venous systems, provide new insight into venous insufficiency pathways. While they function normally in healthy individuals, they can become dilated in chronic venous disease or following surgery. The purpose of this study was to provide an ultrasonographic anatomical description of intranodal varicose veins and to assess possible changes in the stiffness of varicose, dilated inguinal lymph nodes. Methods: The study comprised 92 participants, including 69 women and 23 men, who underwent Doppler ultrasound examinations of the lower-limb venous system, focusing on the groin from both a descriptive morphological and an elastographic perspective. The diagnosis of lymph node varices was made according to established criteria, its severity was assessed using an original classification system, and shear-wave elastography (SWE) values were recorded. Results: More than 83% of patients with operated CVD had lymph node varicose veins. Patients with lymph node varicose veins had larger groin lymph node diameters than patients with CVD without lymph node varicose pathology. The mean shear wave elastography values were significantly lower in the group with lymph node varices compared to the group without (12.2 ± 1.1 kPa vs. 20.1 ± 2.3 kPa; p < 0.05). Elastographic values correlate with lymph node diameter (p = 0.039) and with varicose vein grade (p < 0.001). Conclusions: Intranodal varices may indicate disease progression. These vascular abnormalities impact SWE measurements by altering tissue mechanics. It is imperative to consider the interactions between the lymphatic and venous systems in the management of CVD to improve patient outcomes. Full article