Real world hospital costs following stress echocardiography in the UK: a costing study from the EVAREST/BSE-NSTEP multi-centre study

Background - Stress echocardiography is widely used to detect coronary artery disease, but little evidence on downstream hospital costs in real-world practice is available. We examined how stress echocardiography accuracy and downstream hospital costs vary across NHS hospitals and identified key factors that affect costs to help inform future clinical planning and guidelines. Methods - Data on 7636 patients recruited from 31 NHS hospitals within the UK between 2014 and 2020 as part of EVAREST/BSE-NSTEP clinical study, were used. Data included all diagnostic tests, procedures, and hospital admissions for 12 months after a stress echocardiogram and were costed using the NHS national unit costs. A decision tree was built to illustrate the clinical pathway and estimate average downstream hospital costs. Multi-level regression analysis was performed to identify variation in accuracy and costs at both patient, procedural, and hospital level. Linear regression and extrapolation were used to estimate annual hospital cost-savings associated with increasing predictive accuracy at hospital and national level. Results – Stress echocardiography accuracy varied with patient, hospital and operator characteristics. Hypertension, presence of wall motion abnormalities andhigher number of hospital cardiology outpatient attendances annually reduced accuracy, adjusted odds ratio of 0.78 (95% CI: 0.65 to 0.93), 0.27 (95% CI: 0.15 to 0.48), 0.99 (95% CI: 0.98 to 0.99) respectively, whereas a prior myocardial infarction, angiotensin receptor blocker medication, and greater operator experience increased accuracy, adjusted odds ratio of 1.77 (95% CI: 1.34 to 2.33), 1.64 (95% CI: 1.22 to 2.22), and 1.06 (95% CI: 1.02 to 1.09) respectively. Average downstream costs were £646 per patient (SD 1796) with significant variation across hospitals. The average downstream costs between the 31 hospitals varied from £384-1730 per patient. False positive and false negative tests were associated with average downstream costs of £1446 (SD £601) and £4192 (SD 3332) respectively, driven by increased non-elective hospital admissions, adjusted odds ratio 2.48 (95% CI: 1.08 to 5.66), 21.06 (95% CI: 10.41 to 42.59) respectively. We estimated that an increase in accuracy by 1 percentage point could save the NHS in the UK £3.2 million annually. Conclusion – This study provides real-world evidence of downstream costs associated with stress echocardiography practice in the UK and estimates how improvements in accuracy could impact healthcare expenditure in the NHS. A real-world downstream costing approach could be adopted more widely in evaluation of imaging tests and interventions to reflect actual value for money and support realistic planning

Neurohumoral and ambulatory haemodynamic adaptations following isometric exercise training in unmedicated hypertensive patients

Objective: Hypertension remains the leading modifiable risk factor for cardiovascular disease (CVD). Isometric exercise training (IET) has been shown to be a useful non-pharmacological intervention for reducing resting blood pressure (BP). This study aimed to measure alterations in office BP, ambulatory BP, cardiac autonomic modulation and inflammatory and vascular biomarkers following a programme of IET in unmedicated hypertensive patients. Methods: Twenty-four unmedicated stage 1 hypertensive patients (age 43.8±7.3 years; height, 178.1±7 cm; weight 89.7±12.8 kg) were randomly assigned in a cross-over study design, to 4-weeks of home based IET and control period, separated by a 3-week washout period. Office and Ambulatory BP, cardiac autonomic modulation, and inflammatory and vascular biomarkers were recorded pre and post IET and control periods. Results: Clinic and 24-hour ambulatory BP significantly reduced following IET by 12.4/6.2 mmHg and 11.8/5.6 mmHg in systolic/diastolic BP, respectively (p<0.001 for both), compared to the control. The BP adaptations were associated with a significant (p=0.018) reduction in the average real variability of 24-hour ambulatory BP following IET, compared to control. Cardiac autonomic modulation improved by 11% (p<0.001), baroreceptor reflex sensitivity improved by 47% (p<0.001), and interleukin-6 and asymmetric dimethylarginine reduced by 10% (p=0.022) and 19% (p=0.023), respectively, which differed significantly to the control period. Conclusion: This is the first evidence of durable BP reduction and wider CVD risk benefits of IET in a relevant patient population. Our findings support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of HTN

Myocardial work and left ventricular mechanical adaptations following isometric exercise training in hypertensive patients

Purpose Hypertension is a major risk factor for cardiovascular disease. Isometric exercise training (IET) reduces resting and ambulatory blood pressure; however, few studies have investigated the myocardial adaptations following IET. Methods We randomly assigned 24 unmedicated hypertensive patients in a cross-over study design to 4-weeks of IET and control period, separated by a 3-week washout period. Speckle tracking echocardiography was used to measure left ventricular (LV) mechanics, and global myocardial work indices were derived from non-invasive LV pressure-strain loops constructed from global longitudinal strain (GLS) indexed to brachial systolic blood pressure. Results IET significantly improved GLS (− 2.3 ± 2%, p < 0.001) and global work efficiency (2.8 ± 2%, p < 0.001), and significantly reduced global wasted work (− 42.5 ± 30 mmHg%, p < 0.001) with no significant change during the control period. Conclusions This is the first evidence to demonstrate that IET significantly improved cardiac health in a relevant patient population. Our findings have important clinical implications for patients with high blood pressure and support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of hypertension

Nitrogen deposition does not enhance Sphagnum decomposition

Long-term additions of nitrogen (N) to peatlands have altered bryophyte growth, species dominance, N content in peat and peat water, and often resulted in enhanced Sphagnum decomposition rate. However, these results have mainly been derived from experiments in which N was applied as ammonium nitrate (NH4NO3), neglecting the fact that in polluted areas, wet deposition may be dominated either by NO3- or NH4+. We studied effects of elevated wet deposition of NO3- vs. NH4+ alone (8 or 56 kg N ha(-1) yr(-1) over and above the background of 8 kg N ha(-1) yr(-1) for 5 to 11 years) or combined with phosphorus (P) and potassium (K) on Sphagnum quality for decomposers, mass loss, and associated changes in hummock pore water in an ombrotrophic bog (Whim). Adding N, especially as NH4+, increased N concentration in Sphagnum, but did not enhance mass loss from Sphagnum. Mass loss seemed to depend mainly on moss species and climatic factors. Only high applications of N affected hummock pore water chemistry, which varied considerably over time. Overall, C and N cycling in this N treated bog appeared to be decoupled. We conclude that moss species, seasonal and annual variation in climatic factors, direct negative effects of N (NH4+ toxicity) on Sphagnum production, and indirect effects (increase in pH and changes in plant species dominance under elevated NO3- alone and with PK) drive Sphagnum decomposition and hummock C and N dynamics at Whim. (C) 2016 Elsevier B.V. All rights reserved.Peer reviewe

P and K additions enhance canopy N retention and accelerate the associated leaching

This study evaluated the interactive effects of combined phosphorus (P) and potassium (K) additions on canopy nitrogen (N) retention (CNR) and subsequent canopy leaching at a long-term N manipulation site on Whim bog in south Scotland. Ambient deposition is 8 kg N ha-1 year-1 and an additional 8, 24, and 56 kg N ha-1 year-1 of either ammonium (NH4+) or nitrate (NO3-) with or without P and K has been applied over 11 years. Throughfall N deposition below Calluna vulgaris and foliar N and P concentrations were assessed. Results showed that 60% for low dose and 53% for high dose of NO3- contrasting with 80% for low dose and 38% for high dose of NH4+ onto Calluna was retained by Calluna canopy. The CNR was enhanced by P and K addition in which 84% of NO3 - and 83% of NH4+ for high dose were retained. CNR for NO3- increased the canopy leaching of dissolved organic N (DON) and associated organic anions. NH4+ retention increased canopy leaching of magnesium and calcium through ion exchange. Even over 11-years N exposure without P and K, foliage 29 N:P ratio of Calluna did not increase, suggesting that N exposure did not lead to N saturation of Calluna at Whim bog. Our study concluded that increases in P and K availability enhance CNR of Calluna, but accelerate the associated canopy leaching of DON and base cations, depending on foliar N status

LOOKING INTO THE ENERGY LANDSCAPE OF MYOGLOBIN

Using the haem group of myoglobin as a probe in optical experiments makes it possible to study its conformational fluctuations in real time. Results of these experiments can be directly interpreted in terms of the structure of the potential energy surface of the protein. The current view is that proteins have rough energy landscapes comprising a large number of minima which represent conformational substates, and that these substates are hierarchically organized. Here, we show that the energy landscape is characterized by a number of discrete distributions of;barrier heights each representing a tier within a hierarchy of conformational substates. Furthermore, we provide evidence that the energy surface is self-similar and offer suggestions for a characterization of the protein fluctuations

Nonequilibrium spectral diffusion due to laser heating in stimulated photon echo spectroscopy of low temperature glasses

A quantitative theory is developed, which accounts for heating artifacts in three-pulse photon echo (3PE) experiments. The heat diffusion equation is solved and the average value of the temperature in the focal volume of the laser is determined as a function of the 3PE waiting time. This temperature is used in the framework of nonequilibrium spectral diffusion theory to calculate the effective homogeneous linewidth of an ensemble of probe molecules embedded in an amorphous host. The theory fits recently observed plateaus and bumps without introducing a gap in the distribution function of flip rates of the two-level systems or any other major modification of the standard tunneling model.Comment: 10 pages, Revtex, 6 eps-figures, accepted for publication in Phys. Rev.

Experimental Study of Straight Guiding Structures for Optical Wireless Communications Within a Vehicular Environment

Generous increments in powerful electronic systems and functions have produced significant implications for the vehicular industry, especially in connecting the electronics infrastructure as it is complicated and costly. A limited amount of research has been conducted to investigate proper wireless advancements that might reasonable with the emerging network standard within the context of intravehicular networks. This paper reports an experimental investigation of Optical Wireless Communication (OWC) links within guiding structures for a vehicular environment. The experiment has characterized the infrared transmission characteristics using different types of materials and the influence of the geometry on significant infrared channel parameters. The upper and lower 3-dB frequencies for line of sight (LOS) transmission in the tubes demonstrate that the tubes do not significantly change the frequency response of the transmission but this rather depends on the other channel factors such as materials and geometry

The impact of mortality development on the number of centenarians in England and wales

The world is ageing both at an individual and a population level, and population ageing is truly a global phenomenon. Life expectancies at birth have increased at the global level from 47 years in the mid-20th century to around 70 years today, and are expected to rise to 76 years by the mid-21st century. The proportion of the world’s population aged 60 years and over has increased from 8% in the mid-20th century to 12%, and by 2050 it is expected to reach 21%. The emergence of large numbers of centenarians has accompanied this development. This paper outlines this emergence historically and the likely growth in the number of centenarians in the 21st century, in particular in England and Wales, analysing mortality trends since 1840 and the rise in the number of centenarians in the 20th and 21st centuries. The number of centenarians in England and Wales increased from around 160 in 1922 to almost 12,500 by 2012, but if mortality at all ages had remained constant from 1912 to 2012, then by 2012 the number of centenarians would only have been around 720. By 2100, the number of centenarians is expected to reach around 1.4 million, but if future mortality at all ages were to remain constant, then by 2100 the number of centenarians would be around 78,000. However, if predicted mortality for those aged 55 years and over was to decrease by an additional 5% every 5 years until 2100, then the number of centenarians in England and Wales would reach around 1.8 million by the end of the century

Nitrous oxide emissions from a peatbog after 13 years of experimental nitrogen deposition

Nitrogen deposition was experimentally increased on a Scottish peatbog over a period of 13 years (2002–2015). Nitrogen was applied in three forms, NH3 gas, NH4Cl solution, and NaNO3 solution, at rates ranging from 8 (ambient) to 64 kg N ha−1 yr−1, and higher near the NH3 fumigation source. An automated system was used to apply the nitrogen, such that the deposition was realistic in terms of rates and high frequency of deposition events. We measured the response of nitrous oxide (N2O) flux to the increased nitrogen input. Prior expectations, based on the IPCC default emission factor, were that 1 % of the added nitrogen would be emitted as N2O. In the plots treated with NH4+ and NO3− solution, no response was seen, and there was a tendency for N2O fluxes to be reduced by additional nitrogen, though this was not significant. Areas subjected to high NH3 emitted more N2O than expected, up to 8.5 % of the added nitrogen. Differences in the response are related to the impact of the nitrogen treatments on the vegetation. In the NH4+ and NO3− treatments, all the additional nitrogen is effectively immobilised in the vegetation and top 10 cm of peat. In the NH3 treatment, much of the vegetation was killed off by high doses of NH3, and the nitrogen was presumably more available to denitrifying bacteria. The design of the wet and dry experimental treatments meant that they differed in statistical power, and we are less likely to detect an effect of the NH4+ and NO3− treatments, though they avoid issues of pseudo-replication