Effects of Age and Comorbidities on Intensive Care and 1-year Mortality after HeartMate 3 Implantation

Background: The use of left ventricular assist devices (LVAD) has been rapidly increasing in older people over the past two decades due to their availability as destination therapy. This study aimed to assess the effect of age and comorbidities on the intensive care unit (ICU) and 1-year mortality after HeartMate 3 LVAD implantation. Methods: From 2016 to 2023, all consecutive adult patients implanted with HeartMate 3 LVAD in our tertiary referral center were enrolled in the study. Patients were stratified according to their age at implantation into Group-1 (&lt;45 years), Group-2 (46–64 years), and Group-3 (&gt;65 years). The effect of age and comorbidities on ICU and 1-year mortality were assessed. Results: In total, 135 patients were included (mean age 54±13 years, 79% males). Baseline vital signs, comorbidities, and hemodynamic support were not different between age groups. The older population had significantly lower eGFR (p=0.025), ischemic cardiac diseases as the underlying heart problem (p&lt;0.001), and LVAD as destination therapy (p&lt;0.001). The mortality rate at the ICU and at one year were 90% and 83%, respectively. The median age of the patients who died in the ICU was significantly higher than 63 [56–65] years versus 57 years [49–62, p=0.034). However, age lost its significance with logistic regression analysis. Having a recent major myocardial infarct, high preoperative leukocyte count, and cardiopulmonary bypass time were independent risk factors for ICU mortality. On the other hand, age was an independent risk factor for one-year mortality. Conclusion: Older age predicts increased one-year but not ICU mortality after HeartMate 3 LVAD implantation, while recent major myocardial infarction, high preoperative leukocyte count, and longer cardiopulmonary bypass time were independent risk factors for ICU mortality. Careful patient selection is critical to optimize outcomes after HeartMate 3 LVAD implantation.</p

Theory of biopolymer stretching at high forces

We provide a unified theory for the high force elasticity of biopolymers solely in terms of the persistence length, $\xi_p$, and the monomer spacing, $a$. When the force f>\fh \sim k_BT\xi_p/a^2 the biopolymers behave as Freely Jointed Chains (FJCs) while in the range \fl \sim k_BT/\xi_p < f < \fh the Worm-like Chain (WLC) is a better model. We show that $\xi_p$ can be estimated from the force extension curve (FEC) at the extension $x\approx 1/2$ (normalized by the contour length of the biopolymer). After validating the theory using simulations, we provide a quantitative analysis of the FECs for a diverse set of biopolymers (dsDNA, ssRNA, ssDNA, polysaccharides, and unstructured PEVK domain of titin) for $x \ge 1/2$. The success of a specific polymer model (FJC or WLC) to describe the FEC of a given biopolymer is naturally explained by the theory. Only by probing the response of biopolymers over a wide range of forces can the $f$-dependent elasticity be fully described.Comment: 20 pages, 4 figure

An Agent-Based Computational Economics Approach To Technology Adoption Timing And The Emergence Of Dominant Designs

Dominant technology designs emerge as the sum of adoption decisions across many firms. We take the position that if certain factors drive adoption by an individual firm, then in the aggregate, they may also illuminate the conditions under which a particular dominant design might emerge. In order to show this, we develop an agent-based computational model to explore linkages between firm specific, industry, and environmental factors, such as knowledge overlap, firm size, environmental uncertainty, and the scope of returns to adoption. We show that the significance of these factors varies with the stage of the technology contest. Early in the process, firms that have a compelling reason to adopt (such as to avoid obsolescence of key resources) choose to enter to create momentum for a particular approach. Other firms, due to indifference, inability or uncertainty, may defer until outcomes are clearer or choose not to adopt at all. More importantly, what constitutes a compelling reason for adoption varies with the nature of the firms that lead as innovators and the external environmental factors. On a broad scale, strong regularities in adoption timing and characteristics of technology winners emerge from the analysis

The HgMn Binary Star Phi Herculis: Detection and Properties of the Secondary and Revision of the Elemental Abundances of the Primary

Observations of the Mercury-Manganese star Phi Herculis with the Navy Prototype Optical Interferometer (NPOI) conclusively reveal the previously unseen companion in this single-lined binary system. The NPOI data were used to predict a spectral type of A8V for the secondary star Phi Her B. This prediction was subsequently confirmed by spectroscopic observations obtained at the Dominion Astrophysical Observatory. Phi Her B is rotating at 50 +/-3 km/sec, in contrast to the 8 km/sec lines of Phi Her A. Recognizing the lines from the secondary permits one to separate them from those of the primary. The abundance analysis of Phi Her A shows an abundance pattern similar to those of other HgMn stars with Al being very underabundant and Sc, Cr, Mn, Zn, Ga, Sr, Y, Zr, Ba, Ce, and Hg being very overabundant.Comment: Accepted to ApJ, 45 pages, 11 figure

Green function techniques in the treatment of quantum transport at the molecular scale

The theoretical investigation of charge (and spin) transport at nanometer length scales requires the use of advanced and powerful techniques able to deal with the dynamical properties of the relevant physical systems, to explicitly include out-of-equilibrium situations typical for electrical/heat transport as well as to take into account interaction effects in a systematic way. Equilibrium Green function techniques and their extension to non-equilibrium situations via the Keldysh formalism build one of the pillars of current state-of-the-art approaches to quantum transport which have been implemented in both model Hamiltonian formulations and first-principle methodologies. We offer a tutorial overview of the applications of Green functions to deal with some fundamental aspects of charge transport at the nanoscale, mainly focusing on applications to model Hamiltonian formulations.Comment: Tutorial review, LaTeX, 129 pages, 41 figures, 300 references, submitted to Springer series "Lecture Notes in Physics

First-Line Support by Intra-Aortic Balloon Pump in Non-Ischaemic Cardiogenic Shock in the Era of Modern Ventricular Assist Devices

Objectives: Little is known about circulatory support in cardiogenic shock (CS) from other causes than the acute coronary syndrome or after cardiotomy. We evaluated the effects of first-line intra-aortic balloon pump (IABP) support in this subpopulation of CS patients. Methods: A retrospective study was performed in 27 patients with CS from end-stage cardiomyopathy supported firstly by IABP in the years 2011-2016. Results: At 24 h, lactate decreased from 3.2 (2.1-6.8) to 1.8 (1.2-2.2) mmol/L (p < 0.001). Eighteen patients (67%) defined as IABP responders were successfully bridged to either recovery (n = 7), left ventricular assist device (n = 5), or heart transplantation (n = 6). IABP failed in 9 patients (non-responders, 33%) who either died (n = 7) or needed support by extracorporeal membrane oxygenation (n = 2). At 24 h of IABP support, urinary output was higher (2,660 [1,835-4,440] vs. 1,200 [649-2,385] mL; p = 0.02) and fluid balance more negative (-1,564 [-2,673 to -1,086] vs. -500 [-930 to +240] mL; p < 0.001) in responders than non-responders. Overall survival at 1 year was 63%. Conclusion: In most patients, first-line support by IABP in end-stage cardiomyopathy is associated with improvement in organ perfusion and clinical stabilisation for at least 24 h allowing time for decision making on next therapies

The chemical abundance analysis of normal early A- and late B-type stars

Modern spectroscopy of early-type stars often aims at studying complex physical phenomena. Comparatively less attention is paid to identifying and studying the "normal" A- and B-type stars and testing how the basic atomic parameters and standard spectral analysis allow one to fit the observations. We wish to stablish whether the chemical composition of the solar photosphere can be regarded as a reference for early A- and late B-type stars. We have obtained optical high-resolution, high signal-to-noise ratio spectra of three slowly rotating early-type stars (HD 145788, 21 Peg and pi Cet) that show no obvious sign of chemical peculiarity, and performed a very accurate LTE abundance analysis of up to 38 ions of 26 elements (for 21 Peg), using a vast amount of spectral lines visible in the spectral region covered by our spectra. We provide an exhaustive description of the abundance characteristics of the three analysed stars with a critical review of the line parameters used to derive the abundances. We compiled a table of atomic data for more than 1100 measured lines that may be used in the future as a reference. The abundances we obtained for He, C, Al, S, V, Cr, Mn, Fe, Ni, Sr, Y, and Zr are compatible with the solar ones derived with recent 3D radiative-hydrodynamical simulations of the solar photosphere. The abundances of the remaining studied elements show some degree of discrepancy compared to the solar photosphere. Those of N, Na, Mg, Si, Ca, Ti, and Nd may well be ascribed to non-LTE effects; for P, Cl, Sc and Co, non-LTE effects are totally unknown; O, Ne, Ar, and Ba show discrepancies that cannot be ascribed to non-LTE effects. The discrepancies obtained for O (in two stars) and Ne agree with very recent non-LTE abundance analysis of early B-type stars in the solar neighbourhood.Comment: Accepted for publication on Astronomy and Astrophysic

Monitoring of yeast metabolism with calorimetry

A system for calorimetric measurements is established in a 1500 L pilot bioreactor. Saccharomyces cerevisiae, baker’s yeast has three metabolic pathways: 1) purely oxidative, glucose consuming; 2) purely reductive, glucose consuming and ethanol producing and 3) purely oxidative, ethanol consuming. Designing experiments to lead the yeast to a single pathway, the accuracy of the calorimetric measurements are verified. Using on-line data of microbial heat production and substrate consumption, the combustion enthalpies of glucose and ethanol in purely oxidative (aerobic) fed batch fermentations are determined as 15900 and 29000 kJ/kg respectively, Combustion enthalpy of glucose in purely reductive (anaerobic) environment is determined as 511 kJ/kg. These values are in good corresponding with literature data. It is now possible to determine the fraction of substrate uptake utilized for energy (catabolism, k) and biosynthesis (anabolism, a) metabolisms on-line. In oxidative (aerobic) fermentations we determined kSox=0.45 for glucose, kEox=0.63 for ethanol and in reductive (anaerobic) fermentations kSred=0.96 for glucose; the anabolism factors are aSox=0.55, aEox=0.37 and aSred=0.04 respectively. The single pathways can occur together so that an experiment is designed with changing environmental conditions to prove the overall calorimetric model. The result is that measured and the calculated microbial heat energy rates are in good accordance. Calorimetric measurements can be used to monitor yeast metabolism on-line, for advanced control strategies or, to predict fermentations or for designing heat exchanger or bioreactor systems

Functional evaluation of sublingual microcirculation indicates successful weaning from VA-ECMO in cardiogenic shock

Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly adopted for the treatment of cardiogenic shock (CS). However, a marker of successful weaning remains largely unknown. Our hypothesis was that successful weaning is associated with sustained microcirculatory function during ECMO flow reduction. Therefore, we sought to test the usefulness of microcirculatory imaging in the same sublingual spot, using incident dark field (IDF) imaging in assessing successful weaning from VA-ECMO and compare IDF imaging with echocardiographic parameters. Methods: Weaning was performed by decreasing the VA-ECMO flow to 50% (F50) from the baseline

Heart re-transplantation in Eurotransplant

Internationally 3% of the donor hearts are distributed to re-transplant patients. In Eurotransplant, only patients with a primary graft dysfunction (PGD) within 1 week after heart transplantation (HTX) are indicated for high urgency listing. The aim of this study is to provide evidence for the discussion on whether these patients should still be allocated with priority. All consecutive HTX performed in the period 1981-2015 were included. Multivariate Cox' model was built including: donor and recipient age and gender, ischaemia time, recipient diagnose, urgency status and era. The study population included 18 490 HTX, of these 463 (2.6%) were repeat transplants. The major indications for re-HTX were cardiac allograft vasculopathy (CAV) (50%), PGD (26%) and acute rejection (21%). In a multivariate model, compared with first HTX hazards ratio and 95% confidence interval for repeat HTX were 2.27 (1.83-2.82) for PGD, 2.24 (1.76-2.85) for acute rejection and 1.22 (1.00-1.48) for CAV (P < 0.0001). Outcome after cardiac re-HTX strongly depends on the indication for re-HTX with acceptable outcomes for CAV. In contrast, just 47.5% of all hearts transplanted in patients who were re-transplanted for PGD still functioned at 1-month post-transplant. Alternative options like VA-ECMO should be first offered before opting for acute re-transplantation