Bioprosthetic heart valve structural degeneration associated with metabolic syndrome: Mitigation with polyoxazoline modification.

Bioprosthetic heart valves (BHV), made from glutaraldehyde-fixed xenografts, are widely used for surgical and transcatheter valve interventions but suffer from limited durability due to structural valve degeneration (SVD). We focused on metabolic syndrome (MetS), a risk factor for SVD and a highly prevalent phenotype in patients affected by valvular heart disease with a well-recognized cluster of comorbidities. Multicenter patient data (N = 251) revealed that patients with MetS were at significantly higher risk of accelerated SVD and required BHV replacement sooner. Using a next-generation proteomics approach, we identified significantly differential proteomes from leaflets of explanted BHV from MetS and non-MetS patients (N = 24). Given the significance of protein infiltration in MetS-induced SVD, we then demonstrated the protective effects of polyoxazoline modification of BHV leaflets to mitigate MetS-induced BHV biomaterial degeneration (calcification, tissue cross-linking, and microstructural changes) in an ex vivo serum model and an in vivo with MetS rat subcutaneous implants.

Directed Differentiation of Human Induced Pluripotent Stem Cells to Heart Valve Cells.

BACKGROUND: A main obstacle in current valvular heart disease research is the lack of high-quality homogeneous functional heart valve cells. Human induced pluripotent stem cells (hiPSCs)-derived heart valve cells may help with this dilemma. However, there are no well-established protocols to induce hiPSCs to differentiate into functional heart valve cells, and the networks that mediate the differentiation have not been fully elucidated. METHODS: To generate heart valve cells from hiPSCs, we sequentially activated the Wnt, BMP4, VEGF (vascular endothelial growth factor), and NFATc1 signaling pathways using CHIR-99021, BMP4, VEGF-165, and forskolin, respectively. The transcriptional and functional similarity of hiPSC-derived heart valve cells compared with primary heart valve cells were characterized. Longitudinal single-cell RNA sequencing was used to uncover the trajectory, switch genes, pathways, and transcription factors of the differentiation. RESULTS: An efficient protocol was developed to induce hiPSCs to differentiate into functional hiPSC-derived valve endothelial-like cells and hiPSC-derived valve interstitial-like cells. After 6-day differentiation and CD144 magnetic bead sorting, ≈70% CD144+ cells and 30% CD144- cells were obtained. On the basis of single-cell RNA sequencing data, the CD144+ cells and CD144- cells were found to be highly similar to primary heart valve endothelial cells and primary heart valve interstitial cells in gene expression profile. Furthermore, CD144+ cells had the typical function of primary heart valve endothelial cells, including tube formation, uptake of low-density lipoprotein, generation of endothelial nitric oxide synthase, and response to shear stress. Meanwhile, CD144- cells could secret collagen and matrix metalloproteinases, and differentiate into osteogenic or adipogenic lineages like primary heart valve interstitial cells. Therefore, we identified CD144+ cells and CD144- cells as hiPSC-derived valve endothelial-like cells and hiPSC-derived valve interstitial-like cells, respectively. Using single-cell RNA sequencing analysis, we demonstrated that the trajectory of heart valve cell differentiation was consistent with embryonic valve development. We identified the main switch genes (NOTCH1, HEY1, and MEF2C), signaling pathways (TGF-ß, Wnt, and NOTCH), and transcription factors (MSX1, SP5, and MECOM) that mediated the differentiation. Finally, we found that hiPSC-derived valve interstitial-like cells might derive from hiPSC-derived valve endothelial-like cells undergoing endocardial-mesenchymal transition. CONCLUSIONS: In summary, this is the first study to report an efficient strategy to generate functional hiPSC-derived valve endothelial-like cells and hiPSC-derived valve interstitial-like cells from hiPSCs, as well as to elucidate the differentiation trajectory and transcriptional dynamics of hiPSCs differentiated into heart valve cells.

Cooperative Response to Endocardial Notch Reveals Interaction With Hippo Pathway.

BACKGROUND: The endocardium is a crucial signaling center for cardiac valve development and maturation. Genetic analysis has identified several human endocardial genes whose inactivation leads to bicuspid aortic valve formation and calcific aortic valve disease, but knowledge is very limited about the role played in valve development and disease by noncoding endocardial regulatory regions and upstream factors. METHODS: We manipulated Notch signaling in mouse embryonic endocardial cells by short-term and long-term coculture with OP9 stromal cells expressing Notch ligands and inhibition of Notch activity. We examined the transcriptional profile and chromatin accessibility landscape for each condition, integrated transcriptomic, transcription factor occupancy, chromatin accessibility, and proteomic datasets. We generated in vitro and in vivo models with CRISPR-Cas9-edited deletions of various noncoding regulatory elements and validated their regulatory potential. RESULTS: We identified primary and secondary transcriptional responses to Notch ligands in the mouse embryonic endocardium, and a NOTCH-dependent transcriptional signature in valve development and disease. By defining the changes in the chromatin accessibility landscape and integrating with the landscape in developing mouse endocardium and adult human valves, we identify potential noncoding regulatory elements, validated selected candidates, propose interacting cofactors, and define the timeframe of their regulatory activity. Additionally, we found cooperative transcriptional repression with Hippo pathway by inhibiting nuclear Yap (Yes-associated protein) activity in the endocardium during cardiac valve development. CONCLUSIONS: Sequential Notch-dependent transcriptional regulation in the embryonic endocardium involves multiple factors. Notch activates certain noncoding elements through these factors and simultaneously suppresses elements that could hinder cardiac valve development and homeostasis. Biorxviv: https://www.biorxiv.org/content/10.1101/2023.03.23.533882v1.full.

Polymorphic lymphoproliferative disorder arising in a rheumatoid arthritis patient, presenting as fibrin-associated large B-cell lymphoma-like lesions in aortic and mitral valves.

We herein report a case of methotrexate-associated lymphoproliferative disorder (MTX-LPD) showing fibrin-associated large B-cell lymphoma-like heart valve lesions, and Epstein-Barr virus (EBV)-positive mucocutaneous ulcer-like cutaneous and oral mucosal lesions. MTX-LPD is a critical complication that can occur in RA patients who are treated with MTX. EBV also plays a defining or important role in LPDs. Among the sites of MTX-LPD, 40-50% occur in extranodal sites, including the gastrointestinal tract, skin, liver, lung, and kidney. There are few reports of MTX-LPDs involving the heart valves, and to the best of our knowledge, this is the first case to be reported in the English literature. The possibility of EBV-positive LPD should be considered in RA patients, even in patients with an atypical site, as in this case.

The impact of heart valve and partial heart transplant models on the development of banking methods for tissues and organs: A concise review.

Cryopreserved human heart valves fill a crucial role in the treatment for congenital cardiac anomalies, since the use of alternative mechanical and xenogeneic tissue valves have historically been limited in babies. Heart valve models have been used since 1998 to better understand the impact of cryopreservation variables on the heart valve tissue components with the ultimate goals of improving cryopreserved tissue outcomes and potentially extrapolating results with tissues to organs. Cryopreservation traditionally relies on conventional freezing, employing cryoprotective agents, and slow cooling to sub-zero centigrade temperatures; but it is plagued by the formation of ice crystals and cell damage upon thawing. Researchers have identified ice-free vitrification procedures and developed a new rapid warming method termed nanowarming. Nanowarming is an emerging method that utilizes targeted application of energy at the nanoscale level to rapidly rewarm vitrified tissues, such as heart valves, uniformly for transplantation. Vitrification and nanowarming methods hold great promise for surgery, enabling the storage and transplantation of tissues for various applications, including tissue repair and replacement. These innovations have the potential to revolutionize complex tissue and organ transplantation, including partial heart transplantation. Banking these grafts addresses organ scarcity by extending preservation duration while preserving biological activity with maintenance of structural fidelity. While ice-free vitrification and nanowarming show remarkable potential, they are still in early development. Further interdisciplinary research must be dedicated to exploring the remaining challenges that include scalability, optimizing cryoprotectant solutions, and ensuring long-term viability upon rewarming in vitro and in vivo.

Extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock after valve replacement.

BACKGROUND: Limited data evaluated the outcomes of extracorporeal membrane oxygenation (ECMO) in patients with prosthetic valves. This study aimed to compare the outcomes of ECMO support for postcardiotomy cardiogenic shock in patients with mechanical versus bioprosthetic valves. METHODS: This retrospective study included patients with ECMO support for postcardiotomy cardiogenic shock after valve replacement. Patients were grouped into bioprosthetic (n = 49) and mechanical valve (n = 22) groups. RESULTS: There were no differences in ECMO duration, inotropic support, intra-aortic balloon pump (IABP), stroke, duration of ICU, and hospital stay between groups. Postoperative thrombosis occurred in 2 patients with bioprosthetic valves (5.41%) and 2 with mechanical valves (14.29%), p = .30. All patients with thrombosis had central ECMO cannulation, concomitant IABP, and inotropic support during ECMO. All thrombi were related to the mitral valve. Three patients with thrombi had hospital mortality.Survival at 6, 12, and 36 months for bioprosthetic valve patients was 30.88%, 28.55%, and 25.34% and for mechanical valves was 36.36% for all time intervals (Log-rank p = .93). One patient had bioprosthetic aortic valve endocarditis after 1 year. Three patients with bioprosthetic valves had structural valve degeneration after 1, 2, and 5 years. CONCLUSIONS: Outcomes of ECMO in patients with prosthetic valves are comparable between bioprosthetic and mechanical valves. Thrombosis might occur in both valve types and was associated with high mortality. ECMO could affect the long-term durability of the bioprosthetic valves.

Last twenty-years activity of cardiovascular tissue banking in Barcelona.

The Barcelona Tissue Bank was established from the merge of two previous multi-tissue banks. Potential donors are screened by Donor Center staff and multi-tissue retrieval is performed by specialized own teams. Tissue processing and preservation is performed in clean room facilities by specialised personnel. After quality control of both donor and all tissues results, the heart valves and vascular segments are stored until medical request. The aim of this report is to present the cardiovascular tissue activity and retrospectively evaluate the outcomes of the changes performed in last 20 years. Cardiovascular tissue from 4088 donors was received, specifically 3115 hearts and 2095 vascular segments were processed and evaluated. A total of 48% of the aortic valves, 68% of the pulmonary valves and 75% of the vascular segments were suitable for transplant. The main reason for discarding tissue was macroscopic morphology followed by microbiological results, for both valves and arteries. Altogether, 4360 tissues were distributed for transplantation: 2032 (47%) vascular segments, 1545 (35%) pulmonary valves and 781 (18%) aortic valves. The most common indication for aortic valve surgery was the treatment of endocarditis, while for pulmonary valves, it was congenital malformation reconstruction. Vascular segments were mainly used for reconstruction after ischemia. During this period, a number of changes were made with the goal of enhancing tissue quality, safety and efficacy. These improvements were achieved through the use of a new antibiotic cocktail, increasing of donor age criteria and changing the microbiological control strategy.

Collagen and elastic fibers assessment of the human heart valves for age estimation in Thais using image analysis.

The study investigated the relationship between the histological compositions of the tricuspid, pulmonary, mitral, and aortic valves, and age. All 85 fresh human hearts were obtained with an age range between 20 and 90 years. The central area of the valves was conducted to analyze the density of collagen and elastic fibers by using an image analysis program. Neural network function in MATLAB was used for classification data and accuracy test of the age predictive model. Overall, a gradual increase in the density of collagen and elastic fibers was demonstrated with age in all valve types. The pulmonary valve cusps had the least density of collagen and elastic contents, whereas the most dense of collagen was found in the mitral leaflets. A similarity was noted for the elastic fibers in the tricuspid, mitral, and aortic valves. The highest correlation between the collagen (r = 0.629) and elastic fibers (r = 0.713) and age was found in the noncoronary cusp of the aortic valve. The established predictive equations using collagen and elastic fibers in the noncoronary cusp provided the standard error of ± 14.0 and 12.5 years, respectively. A 60.9% of accuracy was found in all age groups using collagen, while accuracy in elastic fibers showed 70.0% in the classification process using the neural networks. The current study provided additional data regarding age-associated changes of collagen and elastic fibers in the human heart valves in Thais and the benefits and application in age forensic identification.

Clear and present danger: Mechanical heart valves in pregnancy.

Specialists in Obstetric Haematology continue to be challenged by pregnant women with mechanical heart valves, who are at high risk of death or severe morbidity. Effective anticoagulation to reduce valve thrombosis inevitably increases risk of obstetric haemorrhage and fetal loss or harm, and difficult decisions need to be made. Lester and mulitdisciplinary colleagues on behalf of the British Society for Haematology review available evidence and provide comprehensive recommendations to guide management in this difficult area. Commentary on: Lester et al. British Society for Haematology guideline for anticoagulant management of pregnant individuals with mechanical heart valves. Br J Haematol 2023;202:465-478.

Cusp-overlap versus coplanar view in transcatheter aortic valve implantation with self-expandable valves: A meta-analysis of comparative studies.

BACKGROUND: Permanent pacemaker implantation (PPI) is a common complication after transcatheter aortic valve implantation (TAVI). The cusp-overlap view (COV) was adopted to reduce PPI risk after TAVI with self-expandable valves (SEVs); however, the evidence remains scarce. We performed a systematic review with meta-analysis comparing COV and the standard coplanar view (CPV) technique to evaluate their effectiveness and safety. METHODS: Following the PRISMA statement, data were extracted from studies published by August 2022 and found in PubMed/MEDLINE, EMBASE, CENTRAL/CCTR, ClinicalTrials.gov, SciELO, LILACS, and Google Scholar. The primary outcome of interest was post-procedural PPI and the secondary outcomes were new left bundle branch block (LBBB), moderate/severe paravalvular leak (PVL), valve dislocation (pop-out); need of second transcatheter heart valve, 30-day mortality, stroke, conversion to surgery, coronary obstruction, implantation depth (mm), and post-TAVI mean gradients (mmHg). RESULTS: Eleven studies met our eligibility criteria and included 1464 patients in the COV group and 1743 patients in the CPV group. Patients who underwent TAVI with COV had lower risk of PPI (odds ratio 0.48; 95% confidence interval [CI] 0.33-0.70; p = 0.001) and higher implantation depths with COV (mean difference -0.83; 95% CI -1.2 to -0.45; p < 0.001). We did not observe any statistically significant differences in the rates of new LBBB, moderate/severe PVL, valve dislocation, need of second transcatheter heart valve, 30-day mortality, stroke, conversion to surgery, coronary obstruction, and post-TAVI mean gradients (mmHg). CONCLUSION: In TAVI with SEVs, the application of COV is associated with lower risk of PPI compared with the standard CPV without increasing risk for adverse outcomes.

Computed tomography-derived membranous septum length as predictor of conduction abnormalities and permanent pacemaker implantation after TAVI: A meta-analysis of observational studies.

BACKGROUND: Permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) is associated with higher risk of mortality and rehospitalization for heart failure. Efforts to prevent conduction abnormalities (CA) requiring PPI after TAVI should be made. The membranous septum (MS) length and its interaction with implantation depth (ID-ΔMSID) could provide useful information about the risk of CA/PPI following TAVI. OBJECTIVES: To identify MS length and ΔMSID as predictors of CA/PPI following TAVI. METHODS: Study-level meta-analysis of studies published by September 30, 2022. RESULTS: Eighteen studies met our eligibility including 5740 patients. Shorter MS length was associated with a significantly higher risk of CA/PPI (per 1 mm decrease: odds ratio [OR] 1.60, 95% confidence interval [CI] 1.28-1.99, p < 0.001). Similarly, lower ΔMSID was associated with a significantly higher risk of CA/PPI (per 1 mm decrease: OR 1.75, 95% CI 1.32-2.31, p < 0.001). Meta-regression analyses revealed a statistically significant modulation of the effect of shorter MS length and lower ΔMSID on the outcome (CA/PPI) by balloon postdilatation (positive regression coefficients with p < 0.001); with increasing use of balloon postdilatation, the effect of shorter MS length and lower ΔMSID on the outcome increased. MS length and ΔMSID demonstrated excellent discriminative abilities, with diagnostic ORs equaling 9.49 (95% CI 4.73-19.06), and 7.19 (95% CI 3.31-15.60), respectively. CONCLUSION: Considering that short MS length and low ΔMSID are associated with higher risk of CA and PPI, we should include measurement of MS length in the pre-TAVI planning with MDCT and try to establish optimal ID values before the procedure to avoid CA/PPI.

KPT-330 Prevents Aortic Valve Calcification via a Novel C/EBPß Signaling Pathway.

[Figure: see text].

Synthesis of High-Molecular-Weight and Strength Polyisobutylene-Based Polyurethane and Its Use for the Development of a Synthetic Heart Valve.

Under optimized synthesis conditions, for the first time, polyisobutylene-based polyurethane (PIB-PU) is prepared with 70% PIB soft segment (i.e., a bioinert and calcification-resistant PU) with Mn > 100 000 Da, 32 MPa ultimate strength, and 630% elongation. The key parameters for this achievement are a) the precise stoichiometry of the polyurethane forming reaction, specifically the use of highly purified di-isocyanate (4,4'-methylene-bis (phenyl isocyanate), MDI), and b) the increased solid content of the synthesis solution to the limit beyond which increased viscosity prevents stirring. The shape of the stress-strain trace of PIB-PU indicates a two-step failure starting with a reversible elastic (Hookean) region up to ≈50% yield, followed by a slower linearly increasing high-modulus-deformation region suggesting the strengthening of PIB soft segments by entanglement/catenation, and the hard segments by progressively ordering urethane domains. This PIB-PU is a candidate for a fully synthetic bioprosthetic heart valve since preliminary studies show that PIB-PU has impressive fatigue life.

The efficacy and safety of direct oral anticoagulants versus vitamin K antagonists in patients with left-sided bioprosthetic heart valves and atrial fibrillation: a systematic review and meta-analysis.

BACKGROUND: The efficacy and safety of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs) for the treatment of patients with left-sided bioprosthetic heart valves (BHV) and atrial fibrillation (AF) remain controversial. This study aims to perform a meta-analysis to evaluate the efficacy and safety of DOACs versus VKAs in this region. METHODS: We retrieved all relevant randomized controlled studies and observational cohort studies, which critically assessed the efficacy and safety of DOACs versus VKAs among patients with left-sided BHV and AF in databases of PubMed, Cochrane, ISI Web of Sciences, and Embase. The efficacy outcomes of this meta-analysis were stroke events and all-cause death when the safety outcomes included major and any bleeding. RESULTS: The analysis integrated 13 studies while enrolling 27,793 patients with AF and left-sided BHV. DOACs reduced the rate of stroke by 33% compared with VKAs (risk ratio [RR] 0.67; 95% CI 0.50-0.91), with no increased incidence of all-cause death (RR 0.96; 95% CI 0.82-1.12). For safety outcomes, major bleeding was reduced by 28% using DOACs rather than VKAs (RR 0.72; 95% CI 0.52-0.99), while there was no difference in the events of any bleeding (RR 0.84; 95% CI 0.68-1.03). In addition, in patients younger than 75 years old, the stroke rate was reduced by 45% in the population using DOACs (RR 0.55; 95% CI 0.37-0.84). CONCLUSION: Our meta-analysis demonstrated that in patients with AF and BHV, compared with VKAs, using DOACs was associated with reduced stroke and major bleeding events without an increase of all-cause mortality and any bleeding. In the population younger than 75 years old, DOAC might be more effective in preventing cardiogenic stroke.

Use of 3D anatomical models in mock circulatory loops for cardiac medical device testing.

INTRODUCTION: Mock circulatory loops (MCLs) are mechanical representations of the cardiovascular system largely used to test the hemodynamic performance of cardiovascular medical devices (MD). Thanks to 3 dimensional (3D) printing technologies, MCLs can nowadays also incorporate anatomical models so to offer enhanced testing capabilities. The aim of this review is to provide an overview on MCLs and to discuss the recent developments of 3D anatomical models for cardiovascular MD testing. METHODS: The review first analyses the different techniques to develop 3D anatomical models, in both rigid and compliant materials. In the second section, the state of the art of MCLs with 3D models is discussed, along with the testing of different MDs: implantable blood pumps, heart valves, and imaging techniques. For each class of MD, the MCL is analyzed in terms of: the cardiovascular model embedded, the 3D model implemented (the anatomy represented, the material used, and the activation method), and the testing applications. DISCUSSIONS AND CONCLUSIONS: MCLs serve the purpose of testing cardiovascular MDs in different (patho-)physiological scenarios. The addition of 3D anatomical models enables more realistic connections of the MD with the implantation site and enhances the testing capabilities of the MCL. Current attempts focus on the development of personalized MCLs to test MDs in patient-specific hemodynamic and anatomical scenarios. The main limitation of MCLs is the impossibility to assess the impact of a MD in the long-term and at a biological level, for which animal experiments are still needed.

Post-COVID-19 fatal Aspergillus endocarditis: A case report.

BACKGROUND: Aspergillus endocarditis (AE) is a rare fatal infection. The infection is often reported in patients with prosthetic heart valves, immunosuppressed, broad-spectrum antimicrobial use regimens, and drug abusers. METHODS: Herein, we report a rare case of native mitral valve AE in a 63-year-old man, with a probable COVID-19-associated invasive pulmonary aspergillosis nine months ago treated with antifungals. RESULTS: In the last admission, the lethargy, neurological deficit, and septic-embolic brain abscess in brain MRI led to suspicion of infective endocarditis. Transesophageal two-dimensional echocardiography and color Doppler flow velocity mapping showed a large highly mobile mass destroying leaflet and severe mitral regurgitation. The Surgical valve replacement is performed. The surgical valve replacement is performed. Direct microscopic examination and culture of the explanted and vegetative mass revealed Aspergillus section Fumiagati confirmed by molecular method. Despite the administration of voriconazole and transient improvement the patient expired. CONCLUSION: As AE is a late consequence of COVID-19-associated invasive pulmonary aspergillosis, therefore, long-term follow-up of invasive aspergillosis, and prompt diagnosis of surgical and systemic antifungal therapy treatment, are warranted to provide robust management.

A New Dissipation Function to Model the Rate-Dependent Mechanical Behavior of Semilunar Valve Leaflets.

A new dissipation function Wv is devised and presented to capture the rate-dependent mechanical behavior of the semilunar heart valves. Following the experimentally-guided framework introduced in our previous work (Anssari-Benam et al., 2022 "Modelling the Rate-Dependency of the Mechanical Behaviour of the Aortic Heart Valve: An Experimentally Guided Theoretical Framework," J. Mech. Behav. Biomed. Mater., 134, p. 105341), we derive our proposed Wv function from the experimental data pertaining to the biaxial deformation of the aortic and pulmonary valve specimens across a 10,000-fold range of deformation rate, exhibiting two distinct rate-dependent features: (i) the stiffening effect in σ-λ curves with increase in rate; and (ii) the asymptotic effect of rate on stress levels at higher rates. The devised Wv function is then used in conjunction with a hyperelastic strain energy function We to model the rate-dependent behavior of the valves, incorporating the rate of deformation as an explicit variable. It is shown that the devised function favorably captures the observed rate-dependent features, and the model provides excellent fits to the experimentally obtained σ-λ curves. The proposed function is thereby recommended for application to the rate-dependent mechanical behavior of heart valves, as well as other soft tissues that exhibit a similar rate-dependent behavior.

Monocyte to HDL ratio may predict thrombosis in patients with mechanical mitral and aortic valve prosthesis.

Increased inflammatory biomarkers have been reported in prosthetic heart valve thrombosis (PHVT). Monocyte to HDL ratio (MHR) and albumin to CRP levels (CAR) are two biomarkers used widely for systemic inflammation but there is a lack of data on prosthetic heart valves. This study aimed to find out the potential predictive value of MHR and CAR for PHVT. Patients who had the diagnosis of mechanical mitral/aortic PHVT and normally functioning prosthesis were retrospectively analyzed. Laboratory data including complete blood count and biochemistry were recorded. Transesophageal echocardiography was performed to diagnose PHVT. The study included 118 patients with mechanical PHVT and 120 patients with normally functioning prosthesis. White blood count, monocyte levels, C-reactive protein, MHR and CAR were significantly higher whereas the lymphocyte, HDL and INR levels on admission were lower in patients with PHVT. Multivariate analysis showed that as well as inadequate anticoagulation, MHR, but not CAR, was found to be an independent predictor of thrombosis in patients with PHVT. Receiver operating characteristic curve analysis was performed to detect the best cut-off value of MHR in the prediction of thrombosis in patients with prosthetic valves. MHR level of > 12.8 measured on admission, yielded an AUC value of 0.791 [(CI 95% 0.733-0.848 p < 0.001) sensitivity 71%, specificity 70%]. Inadequate anticoagulation is the primary cause that leads to thrombosis in mechanical prosthetic valves. Increased MHR, but not CAR, was also shown to be an independent predictor of thrombosis in patients with mechanical mitral and aortic prosthetic valves.

Thinner biological tissues induce leaflet flutter in aortic heart valve replacements.

Valvular heart disease has recently become an increasing public health concern due to the high prevalence of valve degeneration in aging populations. For patients with severely impacted aortic valves that require replacement, catheter-based bioprosthetic valve deployment offers a minimally invasive treatment option that eliminates many of the risks associated with surgical valve replacement. Although recent percutaneous device advancements have incorporated thinner, more flexible biological tissues to streamline safer deployment through catheters, the impact of such tissues in the complex, mechanically demanding, and highly dynamic valvular system remains poorly understood. The present work utilized a validated computational fluid-structure interaction approach to isolate the behavior of thinner, more compliant aortic valve tissues in a physiologically realistic system. This computational study identified and quantified significant leaflet flutter induced by the use of thinner tissues that initiated blood flow disturbances and oscillatory leaflet strains. The aortic flow and valvular dynamics associated with these thinner valvular tissues have not been previously identified and provide essential information that can significantly advance fundamental knowledge about the cardiac system and support future medical device innovation. Considering the risks associated with such observed flutter phenomena, including blood damage and accelerated leaflet deterioration, this study demonstrates the potentially serious impact of introducing thinner, more flexible tissues into the cardiac system.

Outcomes of culture-negative vs. culture-positive infective endocarditis: the ESC-EORP EURO-ENDO registry.

AIM: Fatality of infective endocarditis (IE) is high worldwide, and its diagnosis remains a challenge. The objective of the present study was to compare the clinical characteristics and outcomes of patients with culture-positive (CPIE) vs. culture-negative IE (CNIE). METHODS AND RESULTS: This was an ancillary analysis of the ESC-EORP EURO-ENDO registry. Overall, 3113 patients who were diagnosed with IE during the study period were included in the present study. Of these, 2590 (83.2%) had CPIE, whereas 523 (16.8%) had CNIE. As many as 1488 (48.1%) patients underwent cardiac surgery during the index hospitalization, 1259 (48.8%) with CPIE and 229 (44.5%) with CNIE. The CNIE was a predictor of 1-year mortality [hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.04-1.56], whereas surgery was significantly associated with survival (HR 0.49, 95% CI 0.41-0.58). The 1-year mortality was significantly higher in CNIE than CPIE patients in the medical subgroup, but it was not significantly different in CNIE vs. CPIE patients who underwent surgery. CONCLUSION: The present analysis of the EURO-ENDO registry confirms a higher long-term mortality in patients with CNIE compared with patients with CPIE. This difference was present in patients receiving medical therapy alone and not in those who underwent surgery, with surgery being associated with reduced mortality. Additional efforts are required both to improve the aetiological diagnosis of IE and identify CNIE cases early before progressive disease potentially contraindicates surgery.