Chondroitin Sulfate Derivative Cross-Linking of Decellularized Heart Valve for the Improvement of Mechanical Properties, Hemocompatibility, and Endothelialization

Tissue-engineered heart valve (TEHV) has emerged as a prospective alternative to conventional valve prostheses. The decellularized heart valve (DHV) represents a promising TEHV scaffold that preserves the natural three-dimensional structure and retains essential biological activity. However, the limited mechanical strength, fast degradation, poor hemocompatibility, and lack of endothelialization of DHV restrict its clinical use, which is necessary for ensuring its long-term durability. Herein, we used oxidized chondroitin sulfate (ChS), one of the main components of the extracellular matrix with various biological activities, to cross-link DHV to overcome the above problems. In addition, the ChS-adipic dihydrazide was used to react with residual aldehyde groups, thus preventing potential calcification. The results indicated notable enhancements in mechanical properties and resilience against elastase and collagenase degradation in vitro as well as the ability to withstand extended periods of storage without compromising the structural integrity of valve scaffolds. Additionally, the newly cross-linked valves exhibited favorable hemocompatibility in vitro and in vivo, thereby demonstrating exceptional biocompatibility. Furthermore, the scaffolds exhibited traits of gradual degradation and resistance to calcification through a rat subcutaneous implantation model. In the rat abdominal aorta implantation model, the scaffolds demonstrated favorable endothelialization, commendable patency, and a diminished pro-inflammatory response. As a result, the newly constructed DHV scaffold offers a compelling alternative to traditional valve prostheses, which potentially advances the field of TEHV.

Recent progress in functional modification and crosslinking of bioprosthetic heart valves

Valvular heart disease (VHD), clinically manifested as stenosis and regurgitation of native heart valve, is one of the most prevalent cardiovascular diseases with high mortality. Heart valve replacement surgery has been recognized as golden standard for the treatment of VHD. Owing to the clinical application of transcatheter heart valve replacement technic and the excellent hemodynamic performance of bioprosthetic heart valves (BHVs), implantation of BHVs has been increasing over recent years and gradually became the preferred choice for the treatment of VHD. However, BHVs might fail within 10-15 years due to structural valvular degeneration (SVD), which was greatly associated with drawbacks of glutaraldehyde crosslinked BHVs, including cytotoxicity, calcification, component degradation, mechanical failure, thrombosis and immune response. To prolong the service life of BHVs, much effort has been devoted to overcoming the drawbacks of BHVs and reducing the risk of SVD. In this review, we summarized and analyzed the research and progress on: (i) modification strategies based on glutaraldehyde crosslinked BHVs and (ii) nonglutaraldehyde crosslinking strategies for BHVs.

Benchtop Models of Patient-Specific Intraventricular Flow During Heart Failure and LVAD Support

The characterization of intraventricular flow is critical to evaluate the efficiency of fluid transport and potential thromboembolic risk but challenging to measure directly in advanced heart failure (HF) patients with left ventricular assist device (LVAD) support. The study aims to validate an in-house mock loop (ML) by simulating specific conditions of HF patients with normal and prosthetic mitral valves (MV) and LVAD patients with small and dilated left ventricle volumes, then comparing the flow-related indices result of vortex parameters, residence time (RT), and shear-activation potential (SAP). Patient-specific inputs for the ML studies included heart rate, end-diastolic and end-systolic volumes, ejection fraction, aortic pressure, E/A ratio, and LVAD speed. The ML effectively replicated vortex development and circulation patterns, as well as RT, particularly for HF patient cases. The LVAD velocity fields reflected altered flow paths, in which all or most incoming blood formed a dominant stream directing flow straight from the mitral valve to the apex. RT estimation of patient and ML compared well for all conditions, but SAP was substantially higher in the LVAD cases of the ML. The benchtop system generated comparable and reproducible hemodynamics and fluid dynamics for patient-specific conditions, validating its reliability and clinical relevance. This study demonstrated that ML is a suitable platform to investigate the fluid dynamics of HF and LVAD patients and can be utilized to investigate heart-implant interactions.

Surgical Aortic Valve Replacement in Patients Aged 50 to 70 Years: Mechanical or Bioprosthetic Valve? A Systematic Review

Although transcatheter aortic valve implantation has emerged as a very attractive treatment option for severe aortic valve disease, surgical aortic valve replacement (SAVR) is still considered the standard-of-care, particularly in younger patients. However, selecting the appropriate type of valve prosthesis for this patient population can pose challenges. The aim of this systematic review was to investigate morbidity and mortality in patients aged 50-70 years who have undergone a first-time SAVR, and to define and compare the outcomes of mechanical valve (MV) and biological valve (BV) prosthesis. A systematic search was conducted to investigate the clinical outcomes of MVs and BVs in patients aged 50-70 years following the PRISMA guidelines. A total of 16,111 patients were included in the studies with an average follow-up of 10 years. A total of 16 studies were selected, 12 of which included propensity-score-matching (PMS) analysis and 4 of which obtained results via multivariate analysis. The vast majority (13 studies) showed no greater survival benefit in either MVs and BVs, while three studies showed an advantage of MVs over BVs. Regarding complications, bleeding was the most common adverse event in patients undergoing MV replacement, while for patients receiving BV prosthesis, it was structural valve deterioration and reoperation. Although the data suggest that the BV option could be a safe option in patients younger than 70 years, more studies with contemporary data are needed to draw firm conclusions on the risks and benefits of BV or MV in SAVR. Physicians should individualize the surgical plan based on patient characteristics.

A Study of the Nursing Intervention Based on Self-Efficacy Theory for Patients After Mechanical Heart Valve Replacement: A Randomized Controlled Trial

Aim

To explore the practicability and efficiency of self-efficacy intervention on the nursing for patients after mechanical heart valve replacement (MHVR), so as to provide a theoretical and data foundation for the implementation of self-efficacy intervention in clinical practice.

Methods

This study adopted a randomized controlled trial (RCT). A total of 140 patients undergoing MHVR were randomly divided into the experimental group (normal nursing + self-efficacy intervention) or the control group (normal nursing only) based on a random number table. The primary goal was to evaluate the effect of self-efficacy theory on the self-efficacy of postoperative MHVR patients by General Self-Efficacy Scale (GSES). The secondary goal was to assess the improvement of mental health of postoperative patients as well as their pain through Symptom Checklist 90 (SCL-90) and the visual analogue scale (VAS). The incidence of infection during hospitalization was analyzed, as well as the medication compliance of patients during 3-month follow-up after discharge.

Results

Finally, 136 patients completed the whole trial. The GSES score of the experimental group was notably superior over the control group (p < 0.001), and the SCL-90 scores were lower over the control group. The VAS score of the experimental group was remarkably lower than that of the control group (p < 0.001). The incidence of infection in the experimental group was lower than that in the control group (p = 0.026). The medication compliance of the experimental group was superior to that of the control group (p = 0.030).

Conclusion

Self-efficacy intervention for patients after MHVR could mobilize their self-efficacy, enhance their postoperative medication compliance, and improve their postoperative recovery. This study provides evidence-based medicine (EBM) evidence for the application of self-efficacy theory to postoperative nursing for patients receiving MHVR.

Contemporary trends and in-hospital outcomes of mechanical and bioprosthetic surgical aortic valve replacement in the United States

INTRODUCTION

The choice between a mechanical versus a bioprosthetic valve in aortic valve replacement (AVR) is based on life expectancy, bleeding risk and comorbidities, since bioprosthetic AVR (bAVR) are associated with a more rapid structural deterioration compared to mechanical AVR (mAVR). The impact of widespread transcatheter valve replacements, on the decision to use bAVR versus mAVR, in the contemporary era and subsequent outcomes remain to be determined.

METHODS

The National Inpatient database (2009-2018) was used to study trends in admissions for bAVR and mAVR and in-hospital mortality and outcomes over time. Survey estimation commands were used to determine weighted national estimates.

RESULTS

There were 700,896 ± 18,285 inpatient visits for AVR with 70.1% (95% CI 69.2%-71.1%) and 29.9% (95% CI 28.9%-30.8%) visits for bAVR and mAVR, respectively. Those undergoing bAVR were significantly older (bAVR [69.8 years] vs. mAVR [62.7 years] p < .001]. The rates of mAVR decreased across all age groups during the study period (p_trend  < .001), including patients ≤50 years (p_trend  < .001). In-hospital mortality for mAVR recipients was higher, both after multivariable adjustment (OR 1.35 95% CI 1.26-1.45 p < .001) and propensity matching (mean difference 0.846% ± 0.19%).

CONCLUSION

In the contemporary era, the utilization of mAVR has decreased across all age groups, including those younger than 50 years old. Although mAVR recipients were healthier with less comorbidities, inpatient mortality was higher after mAVR compared to bAVR. In addition to understanding causes for higher in-hospital mortality after mAVR, future research should focus on developing transcatheter valve replacement friendly bAVR.

Incorporating nanocrystalline cellulose into a multifunctional hydrogel for heart valve tissue engineering applications

Functional tissue engineered heart valves (TEHV) have been an elusive goal for nearly 30 years. Among the persistent challenges are the requirements for engineered valve leaflets that possess nonlinear elastic tissue biomechanical properties, support quiescent fibroblast phenotype, and resist osteogenic differentiation. Nanocellulose is an attractive tunable biological material that has not been employed to this application. In this study, we fabricated a series of photocrosslinkable composite hydrogels mNCC-MeGel (mNG) by conjugating TEMPO-modified nanocrystalline cellulose (mNCC) onto the backbone of methacrylated gelatin (MeGel). Their structures were characterized by FTIR, ¹ HNMR and uniaxial compression testing. Human adipose-derived mesenchymal stem cells (HADMSC) were encapsulated within the material and evaluated for valve interstitial cell phenotypes over 14 days culture in both normal and osteogenic media. Compared to the MeGel control group, the HADMSC encapsulated within mNG showed decreased alpha smooth muscle actin (αSMA) expression and increased vimentin and aggrecan expression, suggesting the material supports a quiescent fibroblastic phenotype. Under osteogenic media conditions, HADMSC within mNG hydrogels showed lower expression of osteogenic genes, including Runx2 and osteocalcin, indicating resistance toward calcification. As a proof of principle, the mNG hydrogel, combined with a viscosity enhancing agent, was used to 3D bioprint a tall, self-standing tubular structure that sustained cell viability. Together, these results identify mNG as an attractive biomaterial for TEHV applications.

"A Tale of Two Cities": Anticoagulation Management in Patients with Atrial Fibrillation and Prosthetic Valves in the Era of Direct Oral Anticoagulants

Valvular heart disease and atrial fibrillation often coexist. Oral vitamin K antagonists have represented the main anticoagulation management for antithrombotic prevention in this setting for decades. Novel direct oral anticoagulants (DOACs) are a new class of drugs and currently, due to their well-established efficacy and security, they represent the main therapeutic option in non-valvular atrial fibrillation. Some new evidences are exploring the role of DOACs in patients with valvular atrial fibrillation (mechanical and biological prosthetic valves). In this review we explore the data available in the medical literature to establish the actual role of DOACs in patients with valvular heart disease and atrial fibrillation.

Acrylate-based materials for heart valve scaffold engineering

Calcific aortic valve disease (CAVD) is the most frequent cardiac valve pathology. Its standard treatment consists of surgical replacement either with mechanical (metal made) or biological (animal tissue made) valve prostheses, both of which have glaring deficiencies. In the search for novel materials to manufacture artificial valve tissue, we have conducted a high-throughput screening with subsequent up-scaling to identify non-degradable polymer substrates that promote valve interstitial cells (VICs) adherence/growth and, at the same time, prevent their evolution toward a pro-calcific phenotype. Here, we provide evidence that one of the two identified 'hit' polymers, poly(methoxyethylmethacrylate-co-diethylaminoethylmethacrylate), provided robust VICs adhesion and maintained the healthy VICs phenotype without inducing pro-osteogenic differentiation. This ability was also maintained when the polymer was used to coat a non-woven poly-caprolactone (PCL) scaffold using a novel solvent coating procedure, followed by bioreactor-assisted VICs seeding. Since we observed that VICs had an increased secretion of the elastin-maturing component MFAP4 in addition to other valve-specific extracellular matrix components, we conclude that valve implants constructed with this polyacrylate will drive the biological response of human valve-specific cells.