Donor hypernatremia is associated with increased mortality after heart transplantation

Objective

Donor hypernatremia has been associated with primary graft dysfunction in heart transplantation and is known to be associated with impaired outcome following liver and renal transplantation. However, controversial data exist regarding the impact of sodium deregulation in patient survival after heart transplantation (HTx). This study aims to investigate the impact of donor sodium levels on early morbidity and short- and midterm survival following HTx.

Methods

Between September 2010 and June 2021, a total of n=218 patients underwent HTx in our centre. From those, 214 could be included retrospectively in our study. For each donor, sodium levels were collected and different cut-off levels from 145 to 159 mmol/l were investigated by Kaplan-Meier-analysis. Then, recipients were divided in three groups regarding donor sodium: Normonatremia (133–145 mmol/l, n=73), mild hypernatremia (146–156 mmol/l, n=105) and severe hypernatremia (>156 mmol/l, n=35). Recipient and donor variables were reviewed and compared, including peri- and postoperative characteristics and recipient survival after up to 5 years after transplantation.

Results

All patients were comparable regarding baseline characteristics and perioperative parameters. Regarding early mortality, 90-day survival was significantly reduced only in patients with severe donor hypernatremia in comparison to normonatremia (see table 1 and fifgure 1, 90% vs. 71%, p=0.02), but not in mild normonatremia (89%, p=0.89). 1-year survival was comparable in all groups (p>0.28).

Conclusion

Donor hypernatremia was associated with reduced short-term survival, while correlation weakens >1 year after HTx. Future prospective studies are needed to confirm the possible cut-off value of 156 mmol/l for donor-acceptancy.

Funding Acknowledgement

Type of funding sources: None.

Disorder-Promoted Splitting in Quasiparticle Interference at Nesting Vectors

Inelastic interactions of quantum systems with the environment usually wash coherent effects out. In the case of Friedel oscillations, the presence of disorder leads to a fast decay of the oscillation amplitude. Here we show both experimentally and theoretically that in three-dimensional topological insulator Bi₂Te₃ there is a nesting-induced splitting of coherent scattering vectors which follows a peculiar evolution in energy. The effect becomes experimentally observable when the lifetime of quasiparticles shortens due to disorder. The amplitude of the splitting allows an evaluation of the lifetime of the electrons. A similar phenomenon should be observed in any system with a well-defined scattering vector regardless of its topological properties.

Metal oxide resistive switching: evolution of the density of states across the metal-insulator transition

We report the study of gold-SrTiO3 (STO)-gold memristors where the doping concentration in STO can be fine-tuned through electric field migration of oxygen vacancies. In this tunnel junction device, the evolution of the density of states (DOS) can be followed continuously across the metal-insulator transition (MIT). At very low dopant concentration, the junction displays characteristic signatures of discrete dopant levels. As the dopant concentration increases, the semiconductor band gap fills in but a soft Coulomb gap remains. At even higher doping, a transition to a metallic state occurs where the DOS at the Fermi level becomes finite and Altshuler-Aronov corrections to the DOS are observed. At the critical point of the MIT, the DOS scales linearly with energy N(ϵ)∼ϵ, the possible signature of multifractality.