Biomechanical Analysis of Age-Dependent Changes in Fontan Power Loss

The hemodynamics in Fontan patients with single ventricles rely on favorable flow and energetics, especially in the absence of a subpulmonary ventricle. Age-related changes in energetics for extracardiac and lateral tunnel Fontan procedures are not well understood. Vorticity (VOR) and viscous dissipation rate (VDR) are two descriptors that can provide insights into flow dynamics and dissipative areas in Fontan pathways, potentially contributing to power loss. This study examined power loss and its correlation with spatio-temporal flow descriptors (vorticity and VDR). Data from 414 Fontan patients were used to establish a relationship between the superior vena cava (SVC) to inferior vena cava (IVC) flow ratio and age. Computational flow modeling was conducted for both extracardiac conduits (ECC, n = 16) and lateral tunnels (LT, n = 25) at different caval inflow ratios of 2, 1, and 0.5 that corresponded with ages 3, 8, and 15+. In both cohorts, vorticity and VDR correlated well with PL, but ECC cohort exhibited a slightly stronger correlation for PL-VOR (>0.83) and PL-VDR (>0.89) than that for LT cohort (>0.76 and > 0.77, respectively) at all ages. Our data also suggested that absolute and indexed PL increase (p < 0.02) non-linearly as caval inflow changes with age and are highly patient-specific. Comparison of indexed power loss between our ECC and LT cohort showed that while ECC had a slightly higher median PL for all 3 caval inflow ratio examined (3.3, 8.3, 15.3) as opposed to (2.7, 7.6, 14.8), these differences were statistically non-significant. Lastly, there was a consistent rise in pressure gradient across the TCPC with age-related increase in IVC flows for both ECC and LT Fontan patient cohort. Our study provided hemodynamic insights into Fontan energetics and how they are impacted by age-dependent change in caval inflow. This workflow may help assess the long-term sustainability of the Fontan circulation and inform the design of more efficient Fontan conduits.

Global taxonomic, functional, and phylogenetic diversity of bees in apple orchards

An essential prerequisite to safeguard pollinator species is characterisation of the multifaceted diversity of crop pollinators and identification of the drivers of pollinator community changes across biogeographical gradients. The extent to which intensive agriculture is associated with the homogenisation of biological communities at large spatial scales remains poorly understood. In this study, we investigated diversity drivers for 644 bee species/morphospecies in 177 commercial apple orchards across 33 countries and four global biogeographical biomes. Our findings reveal significant taxonomic dissimilarity among biogeographical zones. Interestingly, despite this dissimilarity, species from different zones share similar higher-level phylogenetic groups and similar ecological and behavioural traits (i.e. functional traits), likely due to habitat filtering caused by perennial monoculture systems managed intensively for crop production. Honey bee species dominated orchard communities, while other managed/manageable and wild species were collected in lower numbers. Moreover, the presence of herbaceous, uncultivated open areas and organic management practices were associated with increased wild bee diversity. Overall, our study sheds light on the importance of large-scale analyses contributing to the emerging fields of functional and phylogenetic diversity, which can be related to ecosystem function to promote biodiversity as a key asset in agroecosystems in the face of global change pressures.

Impact of Age-related change in Caval Flow Ratio on Hepatic Flow Distribution in Fontan

Background

The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac (EC) conduit or a lateral tunnel (LT) connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics.

Objective

The effect of age-related changes in caval inflows on HFD was evaluated using cardiac MRI (CMR) data and patient-specific computational fluid dynamics (CFD) modeling.

Methods

SVC and IVC flow from 414 Fontan patients were collected to establish a relationship between SVC:IVC flow ratio and age. CFD modeling was performed in 60 (30 EC and 30 LT) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively.

Results

SVC:IVC flow ratio inverted at ∼8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC = 2,1, and 0.5 corresponded to ages 3, 8, and 15+ respectively) was not significant for EC but statistically significant for LT cohorts. For all three caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2→0.5 (age 3→15+), the correlation's strength decreased from 0.87→0.64, due to potential flow perturbation as IVC flow momentum increased.

Conclusion

Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of including SVC:IVC variations over time to understand Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.

Clinical Perspective

With improvement in standard of care and management of single ventricle patients with Fontan physiology, the population of adults with Fontan circulation is increasing. Consequently, there is a clinical need to comprehend the impact of patient growth on Fontan hemodynamics. Using CMR data, we were able to quantify the relationship between changing caval inflows and somatic growth. We then used patient-specific computational flow modeling to quantify how this relationship affected the distribution of long-term hepatic flow in extracardiac and lateral tunnel Fontan types. Our findings demonstrated the significance of including SVC:IVC changes over time in CFD modeling to learn more about the long-term hemodynamics of Fontan. Fontan surgical approaches are increasingly planned and optimized using computational flow modeling. For a patient undergoing a Fontan procedure, the workflow presented in this study that takes into account the variations in Caval inflows over time can aid in predicting the long-term hemodynamics in a planned Fontan pathway.

Evaluation of the national governmental efforts between 1997 and 2010 in reducing health inequalities in England

OBJECTIVES

The pandemic has compounded existing inequalities. In the UK, there have been calls for a new cross-government health inequalities strategy. This study aims to evaluate the effectiveness of national governmental efforts between 1997 and 2010, referred to as the National Health Inequalities Strategy (NHIS).

STUDY DESIGN

population-based observational study.

METHODS

Using Global Burden of Disease data, age-standardised years of life lost due to premature mortality (YLL) rates per 10,000 were extracted for 150 Upper Tier Local Authority (UTLA) regions in England for every year between 1990 and 2019. The slope index of inequality was calculated using YLL rates for all causes, individual conditions, and risk factors. Joinpoint regression was used to assess the trends of any changes which arose before, during or after the NHIS.

RESULTS

Absolute inequalities in YLL rates for all causes remained stable between 1990 and 2000, before decreasing over the following 10 years. After 2010, improvements slowed. A similar trend can be observed amongst inequalities in YLLs for individual causes, including ischaemic heart disease, stroke, breast cancer and lung cancer amongst females, and ischaemic heart disease stroke, diabetes and self-harm amongst males. This trend was also observed amongst certain risk factors, notably blood pressure, cholesterol, tobacco and dietary risks. Inequalities were generally greater in males than in females; however, trends were similar across both sexes. The NHIS coincided with significant reductions in inequalities in YLLs due to ischaemic heart disease and lung cancer.

CONCLUSIONS

The findings suggest that the NHIS coincided with a reduction in health inequalities in England. Policy makers should consider a new cross-government strategy to tackle health inequalities drawing from the success of the previous NHIS.

Exploring adherence to an early rule-out pathway for myocardial infarction in the emergency department using mixed-methods

Background

Incorporating a high-sensitivity cardiac troponin assay into a care pathway for the assessment of suspected acute coronary syndrome has enabled myocardial infarction to be ruled out earlier.

Purpose

Using mixed methods, we explored adherence to an early rule-out pathway in the HiSTORIC (High-Sensitivity Cardiac Troponin on Presentation to Rule Out Myocardial Infarction) randomised controlled trial.

Methods

In 16,972 consecutive patients we evaluated clinician adherence to an early rule-out pathway for the assessment of suspected acute coronary syndrome. Adherence was defined in patients with presentation cardiac troponin I concentrations &lt;5ng/L and symptom onset &gt;2 hours from presentation without serial troponin testing (type 1 adherence); presentation troponin &lt;5ng/L and symptom onset ≤2 hours from presentation with serial testing (type 2 adherence); or presentation troponin between 5ng/L and sex-specific 99th centile with serial testing (type 3 adherence). Semi-structured interviews were conducted with 23 clinicians to aid interpretation of the quantitative analysis. Qualitative data were coded and organized into themes.

Results

In patients with troponin &lt;5ng/L presenting &gt;2hr from symptom onset, adherence was achieved in 81% of patients. In patients presenting ≤2hr from symptom onset, 35% of patients had a second troponin test. In patients with an initial troponin concentration between 5ng/L and the 99th centile, 65% of patients had a second troponin test. Compared to patients managed by clinicians who were adherent to the pathway, patients with troponin over-testing (type 1 non-adherence) were more likely to be older (mean age 52±16 years versus 58±14, P&lt;0.001) and have a history of coronary disease (11% versus 27%, P&lt;0.001). In contrast, patients with under testing (type 2 non-adherence) tended to be younger (mean age 49±16 versus 63±15, P&lt;0.001), female (50% versus 37%, P&lt;0.001) and have lower presentation troponin levels (median concentration 1.0ng/L IQR 1.0 to 2.0, versus 5.0ng/L IQR 2.0–10.0) compared to those in whom testing was performed according to pathway recommendations. Semi-structured interview data revealed how pathway adherence was influenced by five main themes: guideline characteristics, patient characteristics, the healthcare practitioner, the healthcare system and scientific evidence. Clear visual pathway layout was fundamental in achieving optimal adherence. Strong clinical suspicion of acute coronary syndrome promoted repeat troponin testing and deviation from the pathway was felt to be justifiable by more senior clinicians.

Conclusion

This analysis revealed successful implementation of the early rule-out pathway with interview data aiding interpretation of trial data. Younger patients with lower troponin concentrations were less likely to receive pathway recommended serial troponin testing. Clinical judgement is one of the main reasons for discontinuation of pathway recommendations.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Brain stem death induces pro-inflammatory cytokine production and cardiac dysfunction in sheep model

Introduction

Organs procured following brain stem death (BSD) are the main source of organ grafts for transplantation. However, BSD is associated with inflammatory responses that may damage the organ and affect both the quantity and quality of organs available for transplant. Therefore, we aimed to investigate plasma and bronchoalveolar lavage (BAL) pro-inflammatory cytokine profiles and cardiovascular physiology in a clinically relevant 6-h ovine model of BSD.

Methods

Twelve healthy female sheep (37–42 Kg) were anaesthetized and mechanically ventilated prior to undergoing BSD induction and then monitored for 6 h. Plasma and BAL endothelin-1 and cytokines (IL-1β, 6, 8 and tumour necrosis factor alpha (TNF-α)) were assessed by ELISA. Differential white blood cell counts were performed. Cardiac function during BSD was also examined using echocardiography, and cardiac biomarkers (A-type natriuretic peptide and troponin I were measured in plasma.

Results

Plasma concentrations big ET-1, IL-6, IL-8, TNF-α and BAL IL-8 were significantly (p < 0.01) increased over baseline at 6 h post-BSD. Increased numbers of neutrophils were observed in the whole blood (3.1 × 10⁹ cells/L [95% confidence interval (CI) 2.06–4.14] vs. 6 × 10⁹ cells/L [95%CI 3.92–7.97]; p < 0.01) and BAL (4.5 × 10⁹ cells/L [95%CI 0.41–9.41] vs. 26 [95%CI 12.29–39.80]; p = 0.03) after 6 h of BSD induction vs baseline. A significant increase in ANP production (20.28 pM [95%CI 16.18–24.37] vs. 78.68 pM [95%CI 53.16–104.21]; p < 0.0001) and cTnI release (0.039 ng/mL vs. 4.26 [95%CI 2.69–5.83] ng/mL; p < 0.0001), associated with a significant reduction in heart contractile function, were observed between baseline and 6 h.

Conclusions

BSD induced systemic pro-inflammatory responses, characterized by increased neutrophil infiltration and cytokine production in the circulation and BAL fluid, and associated with reduced heart contractile function in ovine model of BSD.

Real-world evaluation of follow up strategies after implantable cardiac-defibrillator therapies in patients with ventricular tachycardia (REFINE-VT)

Introduction

Implantable cardiac-defibrillators (ICD) can prevent sudden cardiac death but the risk of recurrent ventricular arrhythmia (VA) and ICD therapies persists. Established strategies to minimize such risks include medication optimization, device reprogramming or ventricular tachycardia (VT) catheter ablation (CA). However, the timing and choice of these strategies at ICD follow-up may not be as consistent in the real-world as the regulated conditions of clinical trials. Furthermore, whether these decisions at follow-up are influenced by the type of arrhythmia, ICD therapy or patient characteristics remain unclear.

Purpose

We evaluated ICD follow-up strategies in patients with ischaemic (ICM) and non-ischaemic cardiomyopathy (NICM) to refine the outpatient management of these complex patients and ultimately improve overall patient outcome.

Methods

REFINE-VT is a retrospective study of 514 patients with ICD/CRT-D who attended ICD follow-up between June 2018 to September 2019 at the University Hospital Coventry & Warwickshire (UHCW) tertiary cardiology department. All follow-ups were face-to-face. Patients were divided into 2 groups according to the absence or presence of sustained VA (e.g. &gt;30 seconds of VT and/or appropriate ICD therapy), described as “negative event” and “positive event” groups respectively. The type of strategy employed in response to a positive event were categorized into 4 groups: (1) Medication change only (2) Device programming +/− medication (3) Referral for VT CA (4) No intervention

Results

514 consecutive patients with ICD (52%) or CRT-D (48%) were analysed. Overall mean age was 67±14 years with 79% male patients. ICM was diagnosed in 329 (64%) patient and NICM in 185 (36%). 437 (85%) patients had no significant VA and/or ICD therapy referred to as the negative group. A total of 77 patients (15%) suffered VA and/or ICD therapies, of whom 22 patients (26%) experienced a second event. 31% (n=24) of this positive event group received no preventative strategy (Table 1). We observed an inconsistent approach to the choice of strategies across different types of arrhythmias and ICD therapies. E.g. the odds of intervening were significantly higher if ICD shock was detected compared to anti-tachycardia pacing (OR 8.4, 95% CI 1.7–39.6, p=0.007). Even in patients with two events, the rate of referral for VT ablation and escalation of antiarrhythmics were similarly as low as patients with a single event (Table 2).

Conclusion

This is the first contemporary study that has evaluated how strategies that reduce the risk of recurrent ICD events are executed in a real-world population. We have demonstrated that the decision to intervene and choices of strategy remain inconsistent and partially biased by the type of arrhythmia and ICD therapy at follow-up. This supports the need for an evidence-driven multi-disciplinary VT clinic to refine and standardize our approach to this heterogeneous population.

Funding Acknowledgement

Type of funding sources: None.

Watching others in a positive state does not induce optimism bias in common marmosets (Callithrix jacchus), but leads to behaviour indicative of competition

Emotional contagion is suggested to facilitate group life by enhancing synchronized responses to the environment. Cooperative breeders are an example of a social system that requires such intricate coordination between individuals. Therefore, we studied emotional contagion in common marmosets by means of a judgement bias test. Demonstrators were exposed to an emotion manipulation (i.e., positive, negative, control), and observers perceived only the demonstrator's behaviour. We predicted that the positive or negative states of the demonstrator would induce matching states in the observer, indicating emotional contagion. All subjects' emotional states were assessed through behaviour and cognition, the latter by means of a judgement bias test. Behavioural results showed a successful emotion manipulation of demonstrators, with manipulation-congruent expressions (i.e., positive calls in the positive condition, and negative calls and pilo-erect tail in the negative condition). Observers showed no manipulation-congruent expressions, but showed more scratching and arousal after the positive manipulation. Concerning the judgement bias test, we predicted that subjects in a positive state should increase their response to ambiguous cues (i.e., optimism bias), and subjects in a negative state should decrease their response (i.e., pessimism bias). This prediction was not supported as neither demonstrators nor observers showed such bias in either manipulation. Yet, demonstrators showed an increased response to the near-positive cue, and additional analyses showed unexpected responses to the reference cues, as well as a researcher identity effect. We discuss all results combined, including recently raised validation concerns of the judgement bias test, and inherent challenges to empirically studying emotional contagion.

Integration of a vertebral fracture identification service into a fracture liaison service: a quality improvement project

Integration of a vertebral fracture identification service into a Fracture Liaison Service is possible. Almost one-fifth of computerised tomography scans performed identified an individual with a fracture. This increase in workload needs to be considered by any FLS that wants to utilise such a service.

INTRODUCTION

This service improvement project aimed to improve detection of incidental vertebral fractures on routine imaging. It embedded a vertebral fracture identification service (Optasia Medical, OM) on routine computerised tomography (CT) scans performed in this hospital as part of its Fracture Liaison Service (FLS).

METHODS

The service was integrated into the hospital's CT workstream. Scans of patients aged ≥ 50 years for 3 months were prospectively retrieved, alongside their clinical history and the CT report. Fractures were identified via OM's machine learning algorithm and cross-checked by the OM radiologist. Fractures identified were then added as an addendum to the original CT report and the hospital FLS informed. The FLS made recommendations based on an agreed algorithm.

RESULTS

In total, 4461 patients with CT scans were retrieved over the 3-month period of which 850 patients had vertebra fractures identified (19.1%). Only 49% had the fractures described on hospital radiology report. On average, 61 patients were identified each week with a median of two fractures. Thirty-six percent were identified by the FLS for further action and recommendations were made to either primary care or the community osteoporosis team within 3 months of fracture detection. Of the 64% not identified for further action, almost half was because the CT was part of cancer assessment or treatment. The remaining were due to a combination of only ≤ 2 mild fractures; already known to a bone health specialist; in the terminal stages of any chronic illness; significant dependency for activities of daily living; or a life expectancy of less than 12 months CONCLUSION: It was feasible to integrate a commercial vertebral fracture identification service into the daily working of a FLS. There was a significant increase in workload which needs to be considered by any future FLS planning to incorporate such a service into their clinical practice.

In-circuit high-frequency jet ventilation to reduce organ motion in a child undergoing sarcoma ablation

Patients with primary or metastatic solid tumours can be treated with minimally invasive image-guided procedures as an alternative to surgical resection. Reducing organ motion during these procedures is crucial so that tumours can be accurately targeted and treatment delivered within a small margin, limiting potential damage to adjacent structures. As ventilation is the main cause of motion, there has been a shift from conventional ventilation towards the use of in-circuit high-frequency jet ventilation techniques for these procedures. We present the case of a 7-year-old who required computed tomography-guided microwave ablation of a right lung metastatic nodule under general anaesthesia. The patient's lungs were ventilated with in-circuit high-frequency jet ventilation in order to provide optimum conditions for ablation. The treatment was successfully completed and she was discharged home the following day. High-frequency jet ventilation is regularly used in our institution for adult computed tomography-guided treatments and to our knowledge, this application has not been described yet in a child this young. Our experience suggests that this technique can be safely used in paediatric patients, though further investigation of the optimum parameters for in-circuit high-frequency jet ventilation in this population is warranted.

Modeling Water Quality in Watersheds: From Here to the Next Generation

In this synthesis, we assess present research and anticipate future development needs in modeling water quality in watersheds. We first discuss areas of potential improvement in the representation of freshwater systems pertaining to water quality, including representation of environmental interfaces, in-stream water quality and process interactions, soil health and land management, and (peri-)urban areas. In addition, we provide insights into the contemporary challenges in the practices of watershed water quality modeling, including quality control of monitoring data, model parameterization and calibration, uncertainty management, scale mismatches, and provisioning of modeling tools. Finally, we make three recommendations to provide a path forward for improving watershed water quality modeling science, infrastructure, and practices. These include building stronger collaborations between experimentalists and modelers, bridging gaps between modelers and stakeholders, and cultivating and applying procedural knowledge to better govern and support water quality modeling processes within organizations.

The mechanism of supply-demand imbalance and clinical outcomes in patients with type 2 myocardial infarction

Background

Type 2 myocardial infarction is common and associated with substantial risk of adverse clinical outcomes, worse than type 1 myocardial infarction, with as few as 30% of patients still alive at five years. However, this broad diagnostic term encompasses multiple mechanisms of supply-demand imbalance, which may be associated with different risks of adverse outcomes.

Purpose

We aimed to assess the prevalence and clinical outcomes of different mechanisms of supply-demand imbalance related to survival in the High-STEACS (High-Sensitivity Troponin in the Evaluation of patients with Acute Coronary Syndrome) randomised controlled trial.

Methods

The High-STEACS trial was a stepped wedge cluster randomised controlled trial in ten hospitals across Scotland, including 48,282 consecutive patients with suspected acute coronary syndrome. The diagnosis was adjudicated according to the Fourth Universal Definition of Myocardial Infarction. In patients with type 2 myocardial infarction, we prospectively adjudicated the cause for supply demand imbalance. Linkage of electronic healthcare records was used to track investigation, treatments and clinical outcomes. We used the Kaplan-Meier method, the log rank test and cox regression models adjusted for age, sex, renal function and co-morbidities to evaluate the risk of future all-cause mortality between categories.

Results

We identified 1,121 patients with type 2 myocardial infarction (age 74- ± 14, 55% female). At one year, death from any cause occurred in 23% (258/1,121) of patients. The most common reason for supply-demand imbalance was tachyarrhythmia in 55% (616/1,121), followed by hypoxaemia in 20% (219/1,121) of patients. Tachyarrhythmia was associated with reduced future risk of all-cause mortality (adjusted HR 0.69, 95% CI 0.43–1.09), similar to those with type 1 myocardial infarction. Comparatively, patients with hypoxaemia appeared at highest risk (adjusted HR 1.75, 95% CI 1.09–2.80).

Conclusion

The mechanism of myocardial oxygen supply-demand imbalance is associated with future prognosis, and should be considered when risk stratifying patients with type 2 myocardial infarction.

Supply-demand imbalance survival

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Endothelin receptor antagonist improves donor lung function in an ex vivo perfusion system

BACKGROUND

A lung transplant is the last resort treatment for many patients with advanced lung disease. The majority of donated lungs come from donors following brain death (BD). The endothelin axis is upregulated in the blood and lung of the donor after BD resulting in systemic inflammation, lung damage and poor lung graft outcomes in the recipient. Tezosentan (endothelin receptor blocker) improves the pulmonary haemodynamic profile; however, it induces adverse effects on other organs at high doses. Application of ex vivo lung perfusion (EVLP) allows the development of organ-specific hormone resuscitation, to maximise and optimise the donor pool. Therefore, we investigate whether the combination of EVLP and tezosentan administration could improve the quality of donor lungs in a clinically relevant 6-h ovine model of brain stem death (BSD).

METHODS

After 6 h of BSD, lungs obtained from 12 sheep were divided into two groups, control and tezosentan-treated group, and cannulated for EVLP. The lungs were monitored for 6 h and lung perfusate and tissue samples were processed and analysed. Blood gas variables were measured in perfusate samples as well as total proteins and pro-inflammatory biomarkers, IL-6 and IL-8. Lung tissues were collected at the end of EVLP experiments for histology analysis and wet-dry weight ratio (a measure of oedema).

RESULTS

Our results showed a significant improvement in gas exchange [elevated partial pressure of oxygen (P = 0.02) and reduced partial pressure of carbon dioxide (P = 0.03)] in tezosentan-treated lungs compared to controls. However, the lungs hematoxylin-eosin staining histology results showed minimum lung injuries and there was no difference between both control and tezosentan-treated lungs. Similarly, IL-6 and IL-8 levels in lung perfusate showed no difference between control and tezosentan-treated lungs throughout the EVLP. Histological and tissue analysis showed a non-significant reduction in wet/dry weight ratio in tezosentan-treated lung tissues (P = 0.09) when compared to control.

CONCLUSIONS

These data indicate that administration of tezosentan could improve pulmonary gas exchange during EVLP.

89 Poor Attendance for DXA in Older People with A Low Trauma Fragility Fracture: A 6 Year Data Analysis of the Nottingham Fracture Liaison Service

Introduction

Hip Fractures are common and result in significant patient morbidity and increased mortality. Up to 40% of these patients have sustained a previous low-trauma fracture. The Department of Health advises that patients presenting with fragility fracture should have access to ‘Fracture Liaison Services (FLS)’. These are models of care which systematically identify patients at risk, assess bone health, treat patients (if needed) and follow patients up to support medication adherence.

Methods

Demographics of FLS patients between January 2012 and December 2017 was obtained retrospectively from the Nottingham University Hospitals FLS database. We examined DNA rates and further characteristics of these types of patients. Deprivation scores were deprived using the English indices of deprivation 2015 (1–Most deprived; 5-Least deprived). The 2016 cohort of patients were followed-up till January 2019 to assess for re-fractures.

Results

6528 high-risk patients were identified and referred to DXA. Mean (SD) age was 68±10.5 years [Females=5302 (81%)]. 1386 patients (21%) did not attend. High prevalence of non-attendance was in females [1032 patients (74%)] and the most deprived individuals [398 patients (29%)]. Females from the most deprived areas had the highest DNA rate [287 patients (29%)]. All eligible patients &gt;75 years old were referred (n=1542 (100%), [Females=1284 (83%), non-attendance=473 (31%), non-attendance in females=390 (82%), highly deprived females=96 (25%)]. 826 patients were referred in 2016. Median follow-up time was 2.46 years (IQR 0.16–3.00 years). 52 patients (7%) re-fractured. 17 patients (33%) DNA their previous DXA scan [Females=12 patients (71%)].

Conclusions

Nottingham FLS have identified patients with fragility fractures that are high-risk for further fractures. Despite a dedicated FLS there is a DNA of 21%. Many patients that DNA are generally considered as having a high-risk of further fractures; females, older age and more deprived. Further studies are needed to explore why patients do not attend for bone density scanning.

247Safety and efficacy of high-sensitivity cardiac troponin for risk stratification in patients with suspected acute coronary syndrome

Background

Guidelines acknowledge the emerging role of high-sensitivity cardiac troponin (hs-cTn) assays for the risk stratification and rapid rule-out of myocardial infarction, but multiple approaches have been described. We previously demonstrated the utility of a single hs-cTnI concentration <5 ng/L at presentation to risk stratify patients with suspected acute coronary syndrome (ACS).

Purpose

To assess the safety and efficacy of a hs-cTnI concentration <5 ng/L at presentation in consecutive patients included in the High-STEACS (High-SensitivityTroponin in the Evaluation of patients with Acute Coronary Syndrome) randomised controlled trial.

Methods

The High-STEACS trial was a stepped wedge cluster randomised controlled trial in ten hospitals across Scotland that included 48,282 patients in whom high-sensitivity cardiac troponin was requested by the attending clinician for evaluation of suspected ACS. Patients with ST-segment elevation myocardial infarction (STEMI) were excluded. We evaluated the negative predictive value (NPV) and sensitivity of a presentation hs-cTnI <5 ng/L for a composite outcome of type 1 myocardial infarction, or subsequent type 1 myocardial infarction or cardiac death at 30 days. To assess safety, we report the one-year risk of type 1 myocardial infarction or cardiac death. To assess efficacy, we report the proportion of patients with cardiac troponin <5 ng/L at presentation.

Results

We included 47,101 consecutive patients in the analysis (mean 61±17 years old, 47% female). Of these patients, 27,500 (58%) had a cardiac troponin <5 ng/L at presentation. Overall, 4,313/47,101 (9%) patients had a composite outcome at 30 days, but the event rate was only 0.4% in those with troponin <5 ng/L (98/27,500). The NPV for the composite outcome in those <5 ng/L was 99.7% (95% confidence intervals [CI] 99.6–99.7) and the sensitivity was 98.0% (95% CI 97.6–98.4). In those without evidence of myocardial injury at presentation (hs-cTnI <99thcentile), type 1 myocardial infarction or cardiac death at one year occurred in 197 (0.7%) patients with cardiac troponin <5 ng/L, compared to 647 (5.5%) of those ≥5 ng/L. The NPV was unchanged across all age groups, although efficacy fell as fewer older patients had hs-cTnI concentrations below the risk stratification threshold (see Figure).

Conclusion

A hs-cTnI concentration <5 ng/L at presentation identifies the majority of patients with suspected ACS as low-risk of early or late cardiac events. Although the proportion identified as low risk is reduced in older populations, the safety of this risk stratification approach is maintained across patients of all ages.

Acknowledgement/Funding

British Heart Foundation

P3593Improving the performance of high-sensitivity cardiac troponin for the diagnosis of myocardial infarction

Background

The Universal Definition of Myocardial Infarction (UDMI) mandates a rise and/or fall in high-sensitivity cardiac troponin (hs-cTn) concentration with at least one measure above the 99th centile of a healthy reference population. However, the 99th centile varies by age, sex, and prevalence of comorbid disease within reference populations, and the application of a single threshold may create diagnostic uncertainty in unselected patients attending the Emergency Department.

Purpose

To compare performance of hs-cTnI at the 99th centile with a model that includes additional clinical variables, for the diagnosis of type 1 myocardial infarction.

Methods

The High-Sensitivity Troponin in the Evaluation of patients with Acute Coronary Syndrome (High-STEACS trial) was a stepped wedge cluster randomised controlled trial of 48,282 consecutive patients across 10 hospitals in Scotland. We evaluated the positive predictive value (PPV) of a hs-cTnI >99th centile for a diagnosis of type 1 myocardial infarction. Patients with ST-segment elevation myocardial infarction (STEMI) were excluded, and all were adjudicated according to the 4th UDMI. The study population was randomly divided into derivation (80%) and internal validation (20%) cohorts. Using generalised additive modelling, we tested the effect of adding clinically relevant variables to hs-cTnI for the prediction of type 1 myocardial infarction in the derivation cohort, and assessed performance of the final model in the validation cohort.

Results

We included 47,101 consecutive patients (61±17 years, 47% female), of whom 9,057 (19%) had at least one hs-cTnI >99th centile (7,207 in derivation and 1,850 in validation cohorts). There were 4,087 (45%) patients with type 1 myocardial infarction, with 3239 (45%) and 848 (46%) in the derivation and validation cohorts, respectively. Across the study population, PPV for type 1 myocardial infarction reduced markedly with increasing age (Figure). Age, sex, chest pain, ischaemia on the electrocardiogram, creatinine and rate of change of hs-cTnI were included in the model. Comorbidities (ischaemic heart disease, diabetes, stroke and hyperlipidaemia) did not improve model performance. In the validation cohort, the area under the curve (AUC) for type 1 myocardial infarction using the 99th centile alone was 0.72 (95% CI 0.70–0.74), whereas the AUC for the optimised model was 0.84 (95% CI 0.82–0.85) (p<0.001 by DeLong's test for difference, see Figure).

Figure 1

Conclusion

The diagnostic performance of the 99th centile for type 1 myocardial infarction is poor, particularly in older populations. A simple model including readily available clinical features improves diagnostic performance and with further external validation could support more individualised treatment decisions.

Acknowledgement/Funding

British Heart Foundation

P3598Cardiac Cycle - The effect of exercise on cardiac troponin release

Introduction

International guidelines recommend the use of low concentrations of high-sensitivity cardiac troponin to risk stratify patients with suspected acute coronary syndrome, however, troponin concentration may also rise due to physical exercise. Interpreting cardiac troponin concentration in this context is challenging because the magnitude and duration of troponin elevation following physical exercise is uncertain.

Purpose

To determine the effect of intensity and duration of physical exercise on cardiac troponin concentration.

Methods

We invited 10 physically active healthy volunteers (7 male and 3 female; mean age: 34±7) to attend 3 study visits, during which they underwent exercise on a stationary bicycle at prespecified intensities and durations. The first visit involved low intensity cycling (50–60% of the participant's lactate threshold [LT]) for 60 minutes. During the second visit, participants cycled at high intensity (80–90% LT) for 60 minutes and during the third study visit, participants cycled at moderate intensity (60–70% LT) for 4 hours. High-sensitivity cardiac troponin I (hs-cTnI) concentration was measured at the start of exercise and every hour up to 6 hours during each study visit and subsequently at 1, 2 and 7 days after each exercise visit.

Results

Study participants had a median hs-cTnI concentration of 1.8 ng/L (interquartile range [IQR] 0.8–5.7 ng/L) at baseline. Cardiac troponin concentration was elevated following moderate- and high-intensity exercise (P=0.006 and P<0.001, respectively) but not following low-intensity exercise (P=0.137). Troponin concentrations were significantly higher following the shorter duration of high-intensity exercise (peak hs-cTnI concentration = 13 ng/L [IQR 6.5–27.1 ng/L]) compared to the longer duration moderate-intensity exercise (peak hs-cTnI concentration = 6.9 ng/L [2.9–7.9 ng/L]; P-value <0.001). Following both moderate- and high-intensity exercise, cardiac troponin concentration returned to baseline within 48 hours (Figure 1).

Troponin concentrations ng/L / time

Conclusions

Our study suggests that elevation in cardiac troponin concentration is associated with the intensity rather than duration of physical exercise, and that exercise-induced troponin elevations resolve within 48 hours. These findings have important implications for the interpretation of cardiac troponin in the risk stratification and diagnosis of patients who present with symptoms suggestive of acute coronary syndrome following physical exercise.

Acknowledgement/Funding

British Heart Foundation

Organ and Tissue Donation in Irish Paediatric Intensive Care

Aim Our aim was to present an overview of patterns of paediatric organ donation in the Republic of Ireland from January 2007 to January 2018. Methods We performed a retrospective audit of organ donation practice in paediatric intensive care units (PICU) in Ireland. Results Thirty-six children donated organs or tissue heart valves over the 11-year period. There were 13 paediatric organ donors between 2007 and 2012, this increased to 23 paediatric organ donors between 2013 and 2017. 2017 had the highest number of organ donors at 9 Conclusion Organ donation in Irish PICUs has increased over the last 11 years due to a combination of factors: improved resourcing and organization of Organ Donation Transplantation Ireland (ODTI), the establishment of clinical leads (both medical and nursing) in organ donation, a heightened awareness of organ donation and improved specialist Intensive Care dedicated consultant staffing. Finally organ donation is possible only through the generosity and altruism of bereaved families. Outcomes from donated organs have been excellent throughout the 11 year period audited.