First human use of a wireless coplanar energy transfer coupled with a continuous-flow left ventricular assist device

The drive-line to power contemporary ventricular assist devices exiting the skin is associated with infection, and requires a holstered performance of the cardiac pump, which reduces overall quality of life. Attempts to eliminate the drive-line using transcutaneous energy transfer systems have been explored but have not succeeded in viable widespread application. The unique engineering of the coplanar energy transfer system is characterized by 2 large rings utilizing a coil-within-the-coil topology, ensuring robust resonance energy transfer while allowing for a substantial (>6 hours) unholstered circulatory support powered by an implantable battery source. Herein we report the first known human experience with this novel technology, coupled with a continuous-flow assist left ventricular assist device, in 2 consecutive patients evaluated with the primary end-point of system performance at 30 days post-implantation. ispartof: JOURNAL OF HEART AND LUNG TRANSPLANTATION vol:38 issue:4 pages:339-343 ispartof: location:United States status: publishe

Pseudogap effects induced by resonant pair scattering

We demonstrate how resonant pair scattering of correlated electrons above T_c can give rise to pseudogap behavior. This resonance in the scattering T-matrix appears for superconducting interactions of intermediate strength, within the framework of a simple fermionic model. It is associated with a splitting of the single peak in the spectral function into a pair of peaks separated by an energy gap. Our physical picture is contrasted with that derived from other T-matrix schemes, with superconducting fluctuation effects, and with preformed pair (boson-fermion) models. Implications for photoemission and tunneling experiments in the cuprates are discussed.Comment: REVTeX3.0; 4 pages, 4 EPS figures (included

Coulomb Correlations and Pseudo-gap Effects in a Pre-formed Pair Model for the Cuprates

We extend previous work on pre-formed pair models of superconductivity to incorporate Coulomb correlation effects. For neutral systems, these models have provided a useful scheme which interpolates between BCS and Bose Einstein condensation with increasing coupling and thereby describes some aspects of pseudo-gap phenomena. However, charge fluctuations (via the plasmon, $\omega_p$) significantly modify the collective modes and therefore the interpolation behavior. We discuss the resulting behavior of the pseudo-gap and thermodynamic quantities such as $T_c$, $\chi$ and $C_v$ as a function of $\omega_p$.Comment: 4 pages RevTeX, 3 ps figures included (Submitted to Physical Review B August 27, 1996

Nephrocalcinosis in farmed salmonids: diagnostic challenges associated with low performance and sporadic mortality

Disease conditions that involve multiple predisposing or contributing factors, or manifest as low performance and/or low-level mortality, can pose a diagnostic challenge that requires an interdisciplinary approach. Reaching a diagnosis may also be limited by a lack of available clinical profile parameter reference ranges to discriminate healthy fish from those affected by specific disease conditions. Here, we describe our experience investigating poorly performing rainbow trout (Oncorhynchus mykiss) in an intensive recirculation aquaculture, where reaching a final diagnosis of nephrocalcinosis was not as straightforward as one would wish. To list the issues making the diagnosis difficult, it was necessary to consider the creeping onset of the problem. Further diagnostic steps needed to ensure success included obtaining comparative data for fish blood profiles and water quality from both test and control aquacultural systems, excluding infections with salmonid pathogenic agents and evaluating necropsy findings. Major events in the pathophysiology of nephrocalcinosis could be reconstructed as follows: aquatic environment hyperoxia and hypercapnia → blood hypercapnia → blood acid-base perturbation (respiratory acidosis) → metabolic compensation (blood bicarbonate elevation and kidney phosphate excretion) → a rise in blood pH → calcium phosphate precipitation and deposition in tissues. This case highlights the need to consider the interplay between water quality and fish health when diagnosing fish diseases and reaching causal diagnoses

Clinical scenarios for use of transvalvular microaxial pumps in acute heart failure and cardiogenic shock – A European experienced users working group opinion

Abstract For patients with myocardial infarct-related cardiogenic shock (CS), urgent percutaneous coronary intervention is the recommended treatment strategy to limit cardiac and systemic ischemia. However, a specific therapeutic intervention is often missing in non-ischemic CS cases. Though drug treatment with inotropes and/or vasopressors may be required to stabilize the patient initially, their ongoing use is associated with excess mortality. Coronary intervention in unstable patients often leads to further hemodynamic compromise either during or shortly after revascularization. Support devices like the intra-aortic balloon pump failed to improve clinical outcomes in infarct-related CS. Currently, more powerful and active hemodynamic support devices unloading the left ventricle such as transvalvular microaxial pumps are available and are being increasingly used. However, as for other devices large randomized trials are not yet available, and device use is based on registry data and expert consensus. In this article, a multidisciplinary group of experienced users of transvalvular microaxial pumps outlines the pathophysiological background on hemodynamic changes in CS, the available mechanical support devices, and current guideline recommendations. Furthermore, different hemodynamic situations in several case-based scenarios are used to illustrate candidate settings and to provide the theoretic and scientific rationale for left-ventricular unloading in these scenarios. Finally, organization of shock networks, monitoring, weaning, and typical complications and their prevention are discussed

Invasive left ventricle pressure-volume analysis: overview and practical clinical implications

Ventricular pressure-volume (PV) analysis is the reference method for the study of cardiac mechanics. Advances in calibration algorithms and measuring techniques brought new perspectives for its application in different research and clinical settings. Simultaneous PV measurement in the heart chambers offers unique insights into mechanical cardiac efficiency. Beat to beat invasive PV monitoring can be instrumental in the understanding and management of heart failure, valvular heart disease, and mechanical cardiac support. This review focuses on intra cardiac left ventricular PV analysis principles, interpretation of signals, and potential clinical applications

Impact of selected comorbidities on the presentation and management of aortic stenosis

Background: Contemporary data regarding the impact of comorbidities on the clinical presentation and management of patients with severe aortic stenosis (AS) are scarce. Methods Prospective registry of severe patients with AS across 23 centres in nine European countries. Results Of the 2171 patients, chronic kidney disease (CKD 27.3%), left ventricular ejection fraction (LVEF) = 2 of these). The decision to perform aortic valve replacement (AVR) was taken in a comparable proportion (67%, 72% and 69%, in patients with 0, 1 and >= 2 comorbidities;p=0.186). However, the decision for TAVI was more common with more comorbidities (35.4%, 54.0% and 57.0% for no, 1 and >= 2;p= 2 comorbidities than in those without (8.7%, 10.0% and 15.7%;p= 2 comorbidities (30.8 days) than in those without (35.7 days;p=0.012). Patients with reduced LVEF tended to be offered an AVR more frequently and with a shorter delay while patients with CKD were less frequently treated. Conclusions: Comorbidities in severe patients with AS affect the presentation and management of patients with severe AS. TAVI was offered more often than SAVR and performed within a shorter time period

NIRS-based monitoring of kidney graft perfusion.

IntroductionAcute early vascular complications are rare, but serious complications after kidney transplantation. They often result in graft loss. For this reason, shortening the diagnostic process is crucial. Currently, it is standard procedure to monitor renal graft perfusion using Doppler ultrasound (DU). With respect to acute vascular complications, the main disadvantage of this type of examination is its periodicity. It would be of great benefit if graft blood perfusion could be monitored continuously during the early postoperative period. It appears evident that a well-designed near infrared spectroscopy (NIRS) monitoring system could prove very useful during the early post-transplantation period. Its role in the immediate diagnosis of vascular complications could result in a significant increase in graft salvage, thus improving the patient's overall quality of life and lowering morbidity and mortality for renal graft recipients. The aim of this study was to design, construct and test such a monitoring system.Materials and methodsWe designed a rough NIRS-based system prototype and prepared a two-stage laboratory experiment based on a laboratory pig model. In the first stage, a total of 10 animals were used to verify and optimize the technical aspects and functionality of the prototype sensor by testing it on the animal kidneys in-vivo. As a result of these tests, a more specific prototype was designed. During the second stage, we prepared a unique laboratory model of a pig kidney autotransplantation and tested the system for long-term functionality on a group of 20 animals. Overall sensitivity and specificity were calculated, and a final prototype was prepared and completed with its own analytic software and chassis.ResultsWe designed and constructed a NIRS-based system for kidney graft perfusion monitoring. The measurement system provided reliable performance and 100% sensitivity when detecting acute diminished blood perfusion of the transplanted kidneys in laboratory conditions.ConclusionThe system appears to be a useful tool for diagnosing diminished blood perfusion of kidney transplants during the early postoperative period. However, further testing is still required. We believe that applying our method in current human transplantation medicine is feasible, and we are confident that our prototype is ready for human testing