Nanoconfined LiBH4 as a Fast Lithium Ion Conductor Blanchard, Didier; Nale, Angeloclaudio; Sveinbjörnsson, Dadi ...
Advanced functional materials,
January 14, 2015, Letnik:
25, Številka:
2
Journal Article
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Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid‐state batteries. LiBH4 is a promising solid electrolyte for ...Li‐ion batteries. It displays high lithium mobility, although only above 110 °C at which a transition to a high temperature hexagonal structure occurs. Herein, it is shown that confining LiBH4 in the pores of ordered mesoporous silica scaffolds leads to high Li+ conductivity (0.1 mS cm−1) at room temperature. This is a surprisingly high value, especially given that the nanocomposites comprise 42 vol% of SiO2. Solid state 7Li NMR confirmed that the high conductivity can be attributed to a very high Li+ mobility in the solid phase at room temperature. Confinement of LiBH4 in the pores leads also to a lower solid‐solid phase transition temperature than for bulk LiBH4. However, the high ionic mobility is associated with a fraction of the confined borohydride that shows no phase transition, and most likely located close to the interface with the SiO2 pore walls. These results point to a new strategy to design low‐temperature ion conducting solids for application in all solid‐state lithium ion batteries, which could enable safe use of Li‐metal anodes.
Confining LiBH4 inside nanopores of mesoporous silica results in stable and high Li+ mobilities persisting to room temperature. The mobility is associated with a LiBH4 phase that does not undergo a structural phase transition, a phase probably located within 1.0 nanometer of the pore walls. This presents a new strategy to design efficient electrolytes for all solid‐state rechargeable lithium batteries.
Dual antiplatelet therapy is commonly used in patients undergoing transcatheter aortic valve implantation (TAVI), but the optimal antiplatelet regimen is uncertain and remains to be determined. The ...objective of this study was to compare 2 strategies of antiplatelet therapy in patients undergoing TAVI. A strategy using monoantiplatelet therapy (group A, n = 164) was prospectively compared with a strategy using dual antiplatelet therapy (group B, n = 128) in 292 consecutive patients undergoing TAVI. The primary end point was a combination of mortality, major stroke, life-threatening bleeding (LTB), myocardial infarction, and major vascular complications at 30 days. All adverse events were adjudicated according to the Valve Academic Research Consortium. The primary end point occurred in 22 patients (13.4%) in the group A and in 30 patients (23.4%) in the group B (hazard ratio 0.51, 95% confidence interval 0.28 to 0.94, p = 0.026). LTB (3.7% vs 12.5%, p = 0.005) and major bleedings (2.4% vs 13.3%, p <0.0001) occurred less frequently in the group A, whereas the incidence of stroke (1.2% vs 4.7%, p = 0.14) and myocardial infarction (1.2% vs 0.8%, p = 1.0) was not significantly different between the 2 groups. The benefit of a strategy using mono versus dual antiplatelet therapy persisted after multivariate adjustment and propensity score analysis (hazard ratio 0.53, 95% confidence interval 0.28 to 0.95, p = 0.033). In conclusion, a strategy using mono versus dual antiplatelet therapy in patients undergoing TAVI reduces LTB and major bleedings without increasing the risk of stroke and myocardial infarction. The results of our study question the justification of dual antiplatelet therapy and require confirmation in a randomized trial.
Complex hydrides, such as LiBH4, are a promising class of ion conductors for all-solid-state batteries, but their application is constrained by low ion mobility at room temperature. Mixing with ...halides or complex hydride anions, i.e., other complex hydrides, is an effective approach to improving the ionic conductivity. In the present study, we report on the reaction of LiBH4 with LiBF4, resulting in the formation of conductive composites consisting of LiBH4, LiF and lithium closo-borates. It is believed that the in-situ formation of closo-borate related species gives rise to highly conductive interfaces in the decomposed LiBH4 matrix. As a result, the ionic conductivity is improved by orders of magnitude with respect to the Li-ion conductivity of the LiBH4, up to 0.9 × 10−5 S cm−1 at 30 °C. The insights gained in this work show that the incorporation of a second compound is a versatile method to improve the ionic conductivity of complex metal hydrides, opening novel synthesis pathways not limited to conventional substituents.
Femoral access is the gold standard for transcatheter aortic valve replacement (TAVR). Guidelines recommend reconsidering surgery when this access is not feasible. However, alternative peripheral ...accesses exist, although they have not been accurately compared with femoral access.
This study compared nonfemoral peripheral (n-FP) TAVR with femoral TAVR.
Using the data from the national prospective French registry (FRANCE TAVI French Transcatheter Aortic Valve Implantation), this study compared the characteristics and outcomes of TAVR procedures according to whether they were performed through a femoral or a n-FP access, using a pre-specified propensity score−based matching between groups. Subanalysis during 2 study periods (2013 to 2015 and 2016 to 2017) and among low/intermediate-low and intermediate-high/high volume centers were performed.
Among 21,611 patients, 19,995 (92.5%) underwent femoral TAVR and 1,616 (7.5%) underwent n-FP TAVR (transcarotid, n = 914 or trans-subclavian, n = 702). Patients in the n-FP access group had more severe disease (mean logistic EuroSCORE 19.95 vs. 16.95; p < 0.001), with a higher rate of peripheral vascular disease, known coronary artery disease, chronic pulmonary disease, and renal failure. After matching, there was no difference in the rate of post-procedural death and complications according to access site, except for a 2-fold lower rate of major vascular complications (odds ratio: 0.45; 95% confidence interval: 0.21 to 0.93; p = 0.032) and unplanned vascular repairs (odds ratio: 0.41; 95% confidence interval: 0.29 to 0.59; p < 0.001) in those who underwent n-FP access. The comparison of outcomes provided similar results during the second study period and in intermediate-high/high volume centers.
n-FP TAVR is associated with similar outcomes compared with femoral peripheral TAVR, except for a 2-fold lower rate of major vascular complications and unplanned vascular repairs. n-FP TAVR may be favored over surgery in patients who are deemed ineligible for femoral TAVR and may be a safe alternative when femoral access risk is considered too high.
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There is limited evidence to support decision making on antiplatelet therapy following transcatheter aortic valve implantation (TAVI). Our aim was to assess the efficacy and safety of aspirin-only ...(ASA) versus dual antiplatelet therapy (DAPT) following TAVI.
We performed a systematic review and pooled analysis of individual patient data from 672 participants comparing single versus DAPT following TAVI. Primary endpoint was defined as the composite of net adverse clinical and cerebral events (NACE) at 1 month, including all-cause mortality, acute coronary syndrome (ACS), stroke, life-threatening and major bleeding.
At 30 days a NACE rate of 13% was observed in the ASA-only and in 15% of the DAPT group (OR 0.83, 95% CI 0.48 to 1.43, p=0.50). A tendency towards less life-threatening and major bleeding was observed in patients treated with ASA (OR 0.56, 95% CI 0.28 to 1.11, p=0.09). Also, ASA was not associated with an increased all-cause mortality (OR 0.91, 95% CI 0.36 to 2.27, p=0.83), ACS (OR 0.5, 95% CI 0.05 to 5.51, p=0.57) or stroke (OR 1.21; 95% CI 0.36 to 4.03, p=0.75).
No difference in 30-day NACE rate was observed between ASA-only or DAPT following TAVI. Moreover, a trend towards less life-threatening and major bleeding was observed in favour of ASA. Consequently the additive value of clopidogrel warrants further investigation.
Abstract Background Elderly patients are underrepresented in acute myocardial infarction trials. Our aim was to determine whether, in elderly patients, changes in management in the past 15 years is ...associated with improved one-year mortality after hospital admission for myocardial infarction. Methods We used data from 4 one-month French registries, conducted 5 years apart from 1995 to 2010, including 3,389 elderly patients (≥75 years). Results From 1995 to 2010, mean age remained stable (82.1 years), similar in ST- and non-ST-elevation myocardial infraction patients. Obesity, diabetes, hypertension, and hypercholesterolemia increased. History of prior myocardial infarction, stroke and peripheral artery disease remained stable, while history of heart failure decreased. Major changes in management were noted: early percutaneous coronary intervention, early treatment with antiplatelet agents, low molecular weight heparin, beta-blockers, angiotensin-converting-enzyme inhibitor or angiotensin receptor blocker and statins all increased. Early mortality after hospital admission decreased from 25.0% to 8.4%. One-year mortality decreased from 36.2% to 20.0% (adjusted hazard ratio 2010 vs 1995: 0.47, 0.39-0.57), both for ST-elevation myocardial infraction (36.8% to 21.1%) and non-ST-elevation myocardial infraction (34.8% to 19.1%). Mortality reduction was observed in all age groups, including those ≥85 years of age (from 46.2% to 31.4%). Study period, however was no longer associated with decreased mortality when variables reflecting management changes were taken into account. Conclusions Early and one-year mortality after hospital admission of elderly patients with acute myocardial infarction has dramatically decreased over the past 15 years. This improvement is likely mediated by increasing use of recommended management strategies. These data support the application of guidelines derived from trials mostly including younger patients to elderly populations as well.
There are little data about patients with cardiogenic shock (CS) who survive the early phase of acute myocardial infarction (AMI). The aim of this study was to assess long-term (5-year) mortality ...among early survivors of AMI, according to the presence of CS at the acute stage.
We analyzed 5-year follow-up data from the French registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI) 2005 registry, a nationwide French survey including consecutive patients admitted for ST or non-ST-elevation AMI at the end of 2005 in 223 institutions.
Of 3670 patients enrolled, shock occurred in 224 (6.1%), and 3411 survived beyond 30 days or hospital discharge, including 99 (2.9%) with shock. Early survivors with CS had a more severe clinical profile, more frequent concomitant in-hospital complications, and were less often managed invasively than those without CS.
In patients surviving the early phase of AMI, CS at the initial stage carries an increased risk of death up to one year after the acute event. Beyond one year, however, mortality is similar to that of patients without shock.
ClinicalTrials.gov number, NCT00673036, Registered May 5, 2008.
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