Design and rationale of re-energize fontan: Randomized exercise intervention designed to maximize fitness in fontan patients

In this manuscript, we describe the design and rationale of a randomized controlled trial in pediatric Fontan patients to test the hypothesis that a live-video-supervised exercise (aerobic+resistance) intervention will improve cardiac and physical capacity; muscle mass, strength, and function; and endothelial function. Survival of children with single ventricles beyond the neonatal period has increased dramatically with the staged Fontan palliation. Yet, long-term morbidity remains high. By age 40, 50% of Fontan patients will have died or undergone heart transplantation. Factors that contribute to onset and progression of heart failure in Fontan patients remain incompletely understood. However, it is established that Fontan patients have poor exercise capacity which is associated with a greater risk of morbidity and mortality. Furthermore, decreased muscle mass, abnormal muscle function, and endothelial dysfunction in this patient population is known to contribute to disease progression. In adult patients with 2 ventricles and heart failure, reduced exercise capacity, muscle mass, and muscle strength are powerful predictors of poor outcomes, and exercise interventions can not only improve exercise capacity and muscle mass, but also reverse endothelial dysfunction. Despite these known benefits of exercise, pediatric Fontan patients do not exercise routinely due to their chronic condition, perceived restrictions to exercise, and parental overprotection. Limited exercise interventions in children with congenital heart disease have demonstrated that exercise is safe and effective; however, these studies have been conducted in small, heterogeneous groups, and most had few Fontan patients. Critically, adherence is a major limitation in pediatric exercise interventions delivered on-site, with adherence rates as low as 10%, due to distance from site, transportation difficulties, and missed school or workdays. To overcome these challenges, we utilize live-video conferencing to deliver the supervised exercise sessions. Our multidisciplinary team of experts will assess the effectiveness of a live-video-supervised exercise intervention, rigorously designed to maximize adherence, and improve key and novel measures of health in pediatric Fontan patients associated with poor long-term outcomes. Our ultimate goal is the translation of this model to clinical application as an "exercise prescription" to intervene early in pediatric Fontan patients and decrease long-term morbidity and mortality.

Edge-to-edge mitral valve repair improves concomitant high-grade tricuspid regurgitation

Background

Mitral regurgitation (MR) and tricuspid regurgitation (TR) often occur simultaneously and symptoms of biventricular heart failure can overlap. There is currently no consensus on the management of combined MR and TR.

Purpose

To evaluate the impact of TR on echocardiographic and functional outcome after M-TEER.

Methods

740 patients underwent M-TEER for moderate-to-severe MR at our center from 2010 to 2021. Patients were analyzed according to severity of concomitant TR: low-grade TR (grade ≤ I (trace - mild)), moderate TR (grade II) and high-grade TR (grade III - V (severe - torrential)). After M-TEER, patients were followed up for 12 months and their echocardiographic and functional outcome was evaluated.

Results

Low-grade TR was present in 279 patients (37.7%), moderate TR in 170 patients (23.0%) and high-grade TR in 291 patients (39.3%) at the time of M-TEER procedure. Patients with moderate to high-grade TR had higher morbidity resulting in higher EuroSCORE II and STS-Score. At baseline more patients had MR grade ≥III in the high-grade TR group (92.8% vs. 87.1% in the low-grade TR group; p=0.023).

Procedural success of M-TEER was achieved similarly in all groups (98.2% vs. 97.6% vs. 95.9%, p=0.22). At discharge 87.6% of patients with low-grade TR and 80.9% of patients with high-grade TR had residual MR grade ≤I (p=0.036). Residual MR grade ≥III was present in 6.0% of low-grade TR patients and 10.5% of high-grade TR patients at discharge (p=0.062). 3 months after M-TEER residual MR ≥III increased to 9.4% vs. 13.4% (p=0.23) and after 12 months further increased to 12.3% vs. 15.3%, respectively (p=0.52).

TR grade decreased rapidly and consistently after M-TEER. 3 months after the procedure only 48.0% of high-grade TR patients still had TR grade ≥III (p<0.001). After 12 months this proportion declined to 46.8% (p=0.99).

High-grade TR patients had significantly higher mortality (21.5% vs. 18.2% vs. 11.1%, p=0.003) up to 12 months after M-TEER. However, TR-grade ≥III did not independently predict mortality (HR 1.326, 95% CI 0.623–2.824, p=0.46).

Conclusion

M-TEER patients with concomitant moderate to high-grade TR had higher morbidity at baseline compared to low-grade TR patients. M-TEER was safe and effective in MR reduction independent of concomitant TR severity. However, high-grade TR patients had an increased risk for mortality after M-TEER, but high-grade TR did not independently predict adverse outcome. After M-TEER TR grade decreased rapidly and significantly in the high-grade TR group.

Funding Acknowledgement

Type of funding sources: None.

Identifying microplastic litter with Laser Induced Breakdown Spectroscopy: A first approach

The broad diversity of microplastic litter requires a selection of analytical techniques to reliably determine the particle's chemical composition. This study demonstrates that Laser Induced Breakdown Spectroscopy (LIBS) can identify microplastic particles based on their spectral fingerprints. By studying the spectral features of polymer reference spectra, microplastic litter can be distinguished from non-plastic materials. The results show that LIBS can be used as a fast in-situ technique for pre-characterization of the microparticle's material and is a possible tool for environmental studies on microplastics.

Reduced brain-derived neurotrophic factor is associated with a loss of serotonergic innervation in the hippocampus of aging mice

Brain-derived neurotrophic factor (BDNF) regulates monoamine neuronal growth, survival and function in development and throughout adulthood. At 18 months of age, mice with constitutive reductions in BDNF expression show decreased serotonin innervation in the hippocampus compared with age-matched wildtype mice. It is not known, however, whether age-accelerated loss of serotonergic innervation in BDNF(+/-) mice occurs in other brain regions, advances beyond 18 months or is associated with alterations in other neurotransmitter systems. In this study, immunocytochemistry was used to assess serotonergic and catecholaminergic innervation in 26-month-old BDNF(+/-) mice. Age-related loss of serotonin axons in the hippocampus was potentiated in BDNF(+/-) mice compared with wildtype mice at this late age, particularly in the CA1 subregion. By contrast, aging BDNF(+/-) mice showed increased serotonin innervation of the basomedial nucleus of the amygdala. In the noradrenergic system, BDNF(+/-) mice showed reduced numbers of cell bodies and fibers in the locus coeruleus compared with age-matched wildtype mice, whereas no changes were observed in dopaminergic innervation with respect to genotype. In vivo zero net flux microdialysis in awake mice showed a significant decrease in extracellular serotonin levels in the hippocampus in BDNF(+/-) mice at 20 months of age. Thus, reduced BDNF is associated with altered serotonergic and noradrenergic innervation in aging mice and, in particular, with accelerated loss of serotonergic innervation to the hippocampus that is manifest as a decrease in basal neurotransmission.