Mechanical Valve

Penn State University is developing a pediatric total artificial heart (pTAH) as a bridge-to-transplant device that supports infants and small children with single ventricle anomalies or biventricular heart failure to address high waitlist mortality rates for patients with severe congenital heart disease. Two issues with mechanical circulatory support devices are thrombus formation and thromboembolic events. This in vitro study characterizes flow within Penn State's pTAH under physiological operating conditions...

BACKGROUND: The impact of mechanical ventilation on the survival of patients supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO) due to severe acute respiratory distress syndrome (ARDS) remains still a focus of research. METHODS: Recent guidelines, randomized trials, and registry data underscore the importance of lung-protective ventilation during respiratory and cardiac support on ECMO. RESULTS: This approach includes decreasing mechanical power delivery by reducing tidal volume and driving pressure as much as possible, using low or very low respiratory rate, and a personalized approach to positive-end expiratory pressure (PEEP) setting...

BACKGROUND: In vitro assessment is mandatory for artificial heart valve development. This study aims to investigate the effects of pulse duplicator features on valve responsiveness, conduct a sensitivity analysis across valve prosthesis types, and contribute on the development of versatile pulse duplicator systems able to perform reliable prosthetic aortic valve assessment under physiologic hemodynamic conditions. METHODS: A reference pulse duplicator was established based on literature...

Cancer drug testing in animals is an extremely poor predictor of the drug's safety and efficacy observed in humans. Hence there is a pressing need for functional testing platforms that better predict traditional and immunotherapy responses in human, live tumor tissue or tissue constructs, and at the same time are compatible with the use of mouse tumor tissue to facilitate building more accurate disease models. Since many cancer drug actions rely on mechanisms that depend on the tumor microenvironment (TME), such platforms should also retain as much of the native TME as possible...

Transcatheter aortic valve replacement (TAVR) has increasingly become a safe, feasible, and widely accepted alternative surgical treatment for patients with severe symptomatic aortic stenosis. However, the incidence of conduction abnormalities associated with TAVR, including left bundle branch block (LBBB) and high-degree atrioventricular block (HAVB), remains high and is often correlated with risk factors such as the severity of valvular calcification, preexisting conditions in patients, and procedural factors...

A substantial number of patients may experience a systemic inflammatory response syndrome (SIRS) and related adverse events after transcatheter aortic valve implantation and endovascular aortic aneurysm repair. Although a clear etiology has not been established, endothelial disruption and tissue-ischemic response secondary to the foreign material may represent the trigger events. A latency period (0-48 hours) may occur between the initial injury and onset of symptoms mirroring an initial local response followed by a systemic response...

This paper presents the novel use of a temporary percutaneous ventricular assist device (pVAD) in a 51-year-old man with an implanted durable left ventricular assist device (d-LVAD). The pre-existing left ventricular assist device was unable to successfully unload the left ventricle, and the addition of the temporary pVAD achieved successful unloading as well as a decrease in pulmonary artery pressures without compromising the function of the right ventricle allowing safe UNOS listing for orthotopic heart transplantation...

Synovial fistulae associated with large defects in capsulo-synovial envelope have been reported rarely, mostly after surgeries or infections. Unlike post arthroscopy synovial fistulae, which may be treated with immobilisation with or without direct repair, surgical obliteration of defect and track is essential for healing of such synovial fistulae. Technical aspect of obliteration emphasized in literature is watertight tensionless closure of the defect. We report surgical technique of closure of one such synovial fistula with Free Fascia Lata Graft with an inbuilt valve mechanism to reduce chances of recurrence...

Non-photochemical quenching (NPQ) is a protective mechanism used by plants to safely dissipate excess absorbed light energy as heat, minimizing photo-oxidative damage. Although the importance of NPQ as a safety valve for photosynthesis is well-known, the physiological and environmental effects of the heat produced remain unclear because the amount of heat produced by NPQ is considered negligible, and its physiological effects have not been directly observed. Here, we calculated the heat produced by NPQ and evaluated its impact on the leaf and global warming based on simplified models...

Cells from different organs in the body experience a range of mechanical and osmotic pressures that change in various diseases, including neurological, cardiovascular, ophthalmological, and renal diseases. Here, we demonstrate the use of an engineered Sensor-Actuator-Modulator (SAM) of microbial origin derived from a mechanosensitive channel of large conductance (MscL) for sensing external mechanical stress and modulating activities of mammalian cells. SAM is reliably expressed in the mammalian cell membrane and acts as a tension-activated pressure release valve...

Since cardiovascular diseases (CVDs) are globally one of the leading causes of death, of which myocardial infarction (MI) can cause irreversible damage and decrease survivors' quality of life, novel therapeutics are needed. Current approaches such as organ transplantation do not fully restore cardiac function or are limited. As a valuable strategy, tissue engineering seeks to obtain constructs that resemble myocardial tissue, vessels, and heart valves using cells, biomaterials as scaffolds, biochemical and physical stimuli...

Impella is a mechanical circulatory support device of a catheter-based intravascular microaxial pump for left ventricular support and unloading. However, nonclinical studies assessing the effects of the extended duration of left ventricular unloading on cardiac recovery are lacking. An animal model using Impella implanted with a less invasive procedure to enable long-term support is required. This study aimed to evaluate the feasibility of an animal model for long-term support with Impella 5.5 implanted through carotid artery access in sheep...

Spontaneous previable rupture of membranes complicates approximately 0.4-0.7% of pregnancies and is associated with severe maternal and neonatal morbidity and mortality. Intra-amniotic inflammation is present in up to 94.4% of cases, most often caused by a bacterial infection. In comparison, the effectiveness of antibiotic therapy in its eradication reaches less than 17%. Inflammatory activity in the amniotic cavity disrupts the physiological development of the fetus with an increase in maternal, fetal, and neonatal inflammatory morbidity through the development of fetal inflammatory response syndrome, maternal chorioamnionitis, and neonatal sepsis...

IMPORTANCE: Aggregated data and long-term follow-up in national health data registers offer the opportunity to compare the performance of mechanical aortic prostheses within the same population. OBJECTIVE: To investigate the clinical performance of mechanical aortic valve prostheses. DESIGN, SETTING, AND PARTICIPANTS: This nationwide cohort study included all 5224 patients who underwent primary mechanical aortic valve replacement in Sweden between January 1, 2003, and December 31, 2018...

Despite progressively uncommon in Western countries, rheumatic heart disease still portrays a significant global burden. In elderly or high-surgical risk patients, plurivalvular disease may require a complex percutaneous approach. Transcatheter aortic valve implantation (TAVI) in patients with previous monoleaflet mitral prosthesis is challenging due to interference between the aortic valve and the rigid mitral mechanical prosthesis "ring." Prior cases report the use of CoreValve or Edwards Sapien aortic valves in patients with adequate mitro-aortic distance...

Mechanical heart valves (MHVs) are thrombogenic and require lifelong anticoagulation with vitamin K antagonists (VKAs) such as warfarin. Periprocedural bridging with unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) aims to reduce the risk of thromboembolic events in patients. Currently, there are no definitive class I recommendations for anticoagulation management in patients with MHVs. In this report, we present the case of a 77-year-old female who was perioperatively bridged with enoxaparin and subsequently developed an acute thrombus...

BACKGROUND: We report a case of a 72-year-old patient developing a significant tricuspid regurgitation (TR) 6 years after a left ventricular assist device (LVAD) implantation. The aim of this case is to demonstrate the feasibility of transcatheter edge-to-edge repair (TEER) of the tricuspid valve and the excellent clinical benefit in long-term follow-up in an LVAD patient. CASE SUMMARY: Our patient presented with recurrent acute heart failure syndrome. After a fulminant myocarditis in 2005, his previous treatment consisted of cardiac resynchronization therapy, TEER of the mitral valve, and LVAD (HeartMate III) implantation...

OBJECTIVES: Mechanical valves still require life-long anticoagulation. Preclinical animal testing is a crucial step in the assessment of valves, however the chosen animal model should be carefully considered, and a well-controlled animal model of mechanical valve thrombosis has not been established yet. In this study, a histopathologic comparison was performed to evaluate the representativity of pigs and sheep as large animal models in bileaflet mechanical valve thrombosis research. METHODS: 10 pigs and 8 sheep were implanted with a bileaflet mechanical valve in pulmonary position...

BACKGROUND: There are limited data comparing hemodynamic valve function in mechanical aortic valve prostheses. We compared the hemodynamic function of two commonly used mechanical aortic valve (AV) prostheses, the On-X and Top Hat valves. METHODS: Retrospective analysis of 512 patients who received AV replacement with On-X (n=252, 49%) or Top Hat (n=260, 51%) mechanical valves between 2011 and 2019. Patients were matched based on select variables. Echocardiographic data were collected pre- and postoperatively over a median follow-up of 1...

The pathophysiology of aortic valve diseases is of predominantly degenerative nature, characterized by calcific aortic valve stenosis, which is associated with a reduction in prognosis. The prevalence of aortic valve insufficiency also increases with advancing age. Timely causal treatment is crucial in the management of aortic valve diseases. Following the indication for intervention, the heart team plays a central role in evaluating the results and making therapeutic decisions that consider the patient's preferences...