Changes in donor heart allocation in the United States without fundamental changes in the system: rearranging deck chairs and elephants in the room

The Impact of Left Ventricular Assist Device Infections on Postcardiac Transplant Outcomes: A Systematic Review and Meta-Analysis

Left ventricular assist devices (LVADs) are associated with numerous short- and long-term complications, including infection. The impact LVAD infections have on clinical outcomes after transplantation is not well established. We sought to determine whether the presence of infection while on LVAD support negatively influences outcomes after cardiac transplantation. We searched electronic databases and bibliographies for full text studies that identified LVAD infections during support and also reported on posttransplant outcomes. A meta-analysis of posttransplant survival was conducted using a random effects model. Of 2,373 records, 13 bridge to transplant (BTT) cohort studies were selected (n = 6,631, 82% male, mean age 50.7 ± 2.7 years). A total of 6,067 records (91.5%) received transplant. There were 3,718 (56.1%) continuous-flow LVADs (CF-LVADs), 1,752 (26.4%) pulsatile LVADs, and 1,161 (17.5%) unknown type records. A total of 2,586 records (39.0%) developed LVAD infections. Patients with LVAD infections were younger (50.5 ± 1.5 vs. 51.3 ± 1.5, p = 0.02), had higher body mass indeices (BMIs) (28.4 ± 0.7 vs. 26.8 ± 0.4, p < 0.01), and longer LVAD support times (347.0 ± 157.6 days vs. 180.2 ± 106.0 days, p < 0.01). Meta-analysis demonstrated increased posttransplant mortality in those patients who had an LVAD infection (hazard ratio [HR] 1.30, 95% CI: 1.16-1.46, p < 0.001). Subgroup meta-analyses by continuous-flow and pulsatile device type demonstrated significant increased risk of death for both types of devices (HR 1.47, 95% CI: 1.22-1.76, p < 0.001 and 1.71, 95% CI: 1.19-2.45, p = 0.004, respectively). Patients who develop LVAD infections are younger, have higher BMIs and longer LVAD support times. Our data suggests that LVAD-related infections result in a 30% increase in postcardiac transplantation mortality. Strategies to prevent LVAD infections should be implemented to improve posttransplant outcomes in this high-risk population.

A novel graphene oxide polymer gel platform for cardiac tissue engineering application

In this study, we demonstrated a Reverse Thermal Gel (RTG), which is injectable and functionalized with GOs (GO-RTG) that changes at room temperature (24 °C) from a mixture to a three-dimensional (3D) matrix gel soon after approaching its body temperature (37 °C). We also presented investigational evidence, which represents that the system of 3D GO-RTG promotes MCs proliferation as well as alignment, supports in long-standing survival of MCs, and enhances the function of MCs when compared with typical 3D plain RTG system and 2D gelatin control groups. Thus, this system of injectable GO-RTG can be capable of using as a negligibly invasive device for engineering efforts of cardiac tissue.

Gold Nanoparticle-Functionalized Reverse Thermal Gel for Tissue Engineering Applications

Utilizing polymers in cardiac tissue engineering holds promise for restoring function to the heart following myocardial infarction, which is associated with grave morbidity and mortality. To properly mimic native cardiac tissue, materials must not only support cardiac cell growth but also have inherent conductive properties. Here, we present an injectable reverse thermal gel (RTG)-based cardiac cell scaffold system that is both biocompatible and conductive. Following the synthesis of a highly functionalizable, biomimetic RTG backbone, gold nanoparticles (AuNPs) were chemically conjugated to the backbone to enhance the system's conductivity. The resulting RTG-AuNP hydrogel supported targeted survival of neonatal rat ventricular myocytes (NRVMs) for up to 21 days when cocultured with cardiac fibroblasts, leading to an increase in connexin 43 (Cx43) relative to control cultures (NRVMs cultured on traditional gelatin-coated dishes and RTG hydrogel without AuNPs). This biomimetic and conductive RTG-AuNP hydrogel holds promise for future cardiac tissue engineering applications.

Retracted Article: Development of functional hydrogels for heart failure

Hydrogel-based approaches were reviewed for cardiac tissue engineering and myocardial regeneration in ischemia-induced heart failure, with an emphasis on functional studies, translational status, and clinical advancements.

Injectable Hydrogels for Cardiac Tissue Engineering

In light of the limited efficacy of current treatments for cardiac regeneration, tissue engineering approaches have been explored for their potential to provide mechanical support to injured cardiac tissues, deliver cardio-protective molecules, and improve cell-based therapeutic techniques. Injectable hydrogels are a particularly appealing system as they hold promise as a minimally invasive therapeutic approach. Moreover, injectable acellular alginate-based hydrogels have been tested clinically in patients with myocardial infarction (MI) and show preservation of the left ventricular (LV) indices and left ventricular ejection fraction (LVEF). This review provides an overview of recent developments that have occurred in the design and engineering of various injectable hydrogel systems for cardiac tissue engineering efforts, including a comparison of natural versus synthetic systems with emphasis on the ideal characteristics for biomimetic cardiac materials.

Matching the Market for Heart Transplantation

Heart transplantation is the most effective therapy for patients with Stage D heart failure with a median life expectancy of ≈10 to 15 years. Unfortunately, many patients die on the waiting list hoping for a chance of survival. The life boat cannot rescue everyone. Over a decade, the donor pool has remained relatively stable, whereas the number of heart transplant candidates has risen. Potential recipients often have many comorbidities and are older because the criteria for heart transplantation has few absolute contraindications. Women, Hispanics, and patients with restrictive heart disease and congenital heart disease are more likely to die while awaiting heart transplantation than men, white patients, and those with either ischemic or dilated cardiomyopathy. To better match the market, we need to (1) increase the donor pool, (2) reduce the waitlist, and (3) improve the allocation system. This review article addresses all 3 options and compares strategies in the United States to those in other countries.