Optimization based ECG watermarking in RDWT-SVD domain

With the increase in point of care services, communication of digital patient records through open network has multi-folded. This digital data is used to obtain the remote medical assistance from the smart healthcare centres. Protecting this data during transmission is a very big challenge. One of the most important medical data is electrocardiogram (ECG) signal which detects the cardiovascular diseases and any alteration in the signal may affect the diagnosis. In this work, an ECG watermarking based on redundant discrete wavelet transform (RDWT) and singular value decomposition (SVD) is developed. First, the ECG signal is converted into 2-D matrix using pan-tompkins algorithm. Then, we use the hybrid of RDWT and SVD to conceal the patient data and logo image into the 2-D ECG image. We also use hybrid of optimization scheme to improve the robustness of the watermark. Preliminary experimental results indicate the optimal invisibility and robustness result is more effective up to 97.89% than the traditional schemes respectively, which makes it suitable for ownership authentication of ECG signal.

Juvenile Generalized Myasthenia Gravis: Presented as Unilateral Blepharoptosis and Successfully Managed with Pulse Intravenous Methylprednisolone

Myasthenia Gravis is a rare autoimmune disorder of childhood and this is rarer in South Asia. We present a pre-pubertal 7 year old female child of seropositive Generalized Juvenile Myasthenia Gravis. She presented with unilateral blepharoptosis and later generalized symptoms appeared. Ice-pack test, Neostigmine challenge test and acetylcholine receptor antibody test were positive. Serum muscle specific tyrosine kinase antibody test was normal. She did not have thymic abnormalities. She did not respond to high dose (26 mg/kg/day) of Pyridostigmine and oral Prednisolone (2 mg/kg/day), but was successfully treated with a combination of pulse intravenous Methylprednisolone (30 mg/kg once a month for 6 months) and daily doses of oral Prednisolone (2 mg/kg/day) along with Pyridostigmine without significant side effects. This combination can be considered a potential inexpensive treatment for Juvenile Myasthenia Gravis in a resource limited area where other immunosuppressive treatments such as intravenous immunoglobulin is expensive and unaffordable.

Hydrogen sulfide: An emerging signaling molecule regulating drought stress response in plants

Hydrogen sulfide (H₂ S) is a small, reactive signaling molecule that is produced within chloroplasts of plant cells as an intermediate in the assimilatory sulfate reduction pathway by the enzyme sulfite reductase. In addition, H₂ S is also produced in cytosol and mitochondria by desulfhydration of l-cysteine catalyzed by l-cysteine desulfhydrase (DES1) in the cytosol and from β-cyanoalanine in mitochondria, in a reaction catalyzed by β-cyano-Ala synthase C1 (CAS-C1). H₂ S exerts its numerous biological functions by post-translational modification involving oxidation of cysteine residues (RSH) to persulfides (RSSH). At lower concentrations (10-1000 μmol L^-1 ), H₂ S shows huge agricultural potential as it increases the germination rate, the size, fresh weight, and ultimately the crop yield. It is also involved in abiotic stress response against drought, salinity, high temperature, and heavy metals. H₂ S donor, for example, sodium hydrosulfide (NaHS), has been exogenously applied on plants by various researchers to provide drought stress tolerance. Exogenous application results in the accumulation of polyamines, sugars, glycine betaine, and enhancement of the antioxidant enzyme activities in response to drought-induced osmotic and oxidative stress, thus, providing stress adaptation to plants. At the biochemical level, administration of H₂ S donors reduces malondialdehyde content and lipoxygenase activity to maintain the cell integrity, causes abscisic acid-mediated stomatal closure to prevent water loss through transpiration, and accelerates the photosystem II repair cycle. Here, we review the crosstalk of H₂ S with secondary messengers and phytohormones towards the regulation of drought stress response and emphasize various approaches that can be addressed to strengthen research in this area.

Phase 2 study of anastrozole in patients with estrogen receptor/progesterone receptor positive recurrent low-grade endometrial stromal sarcomas: The PARAGON trial (ANZGOG 0903)

BACKGROUND

Aromatase inhibitors are standard of care for low-grade endometrial stromal sarcomas (LGESS), based on very high response rates reported in retrospective studies. We evaluated the activity of anastrozole in recurrent/metastatic LGESS patients enrolled in PARAGON, a basket trial of anastrozole in estrogen receptor (ER±)/progesterone receptor (PR+) gynecological cancers.

METHOD

An investigator-initiated, single-arm, prospective open-label trial of anastrozole 1 mg/day in patients with ER ± PR + ve LGESS with measurable disease, treated until progressive disease or unacceptable toxicity. Primary endpoint was clinical benefit (complete/partial response + stable disease) rate (CBR) at 3 months. Secondary endpoints include progression-free survival (PFS), quality of life and toxicity.

RESULTS

15 eligible patients were enrolled. CBR at 3 months was 73% (95% CI: 48-89.1%); unchanged at 6 months. Best response was 26.7%, including complete response in one (6.7%; 95% CI 1.2-29.8%), partial response in three (20%, 95% CI 7.1-45.2%) and stable disease in seven (46.7%). Four patients ceased treatment by 3 months due to progression. Median PFS was not reached (25th percentile: 2.9 months (95% CI: 1.2-NR)). PFS was 73.3%, 73.3% and 66% at 6, 12, and 18 months, respectively. Six patients remained on treatment for an average of 44.2 months (range 34.5-63.6) up until data cut. Toxicity was as expected, with 3 patients stopping due to adverse effects.

CONCLUSION

The 26.7% objective response rate with anastrozole is lower than reported in retrospective series, but the CBR was high and durable. The results underscore the importance of prospective trials in rare cancers.

33 Diagnostic Test Accuracy of the 4AT for Delirium Detection: Systematic Review and Meta-Analysis

Introduction

Detection of delirium in hospitalised older adults is recommended in national and international guidelines. The 4 ‘A’s Test (4AT; www.the4AT.com) is a short (<2 min) instrument for delirium detection that is used internationally as a standard tool in clinical practice. We performed a systematic review and meta-analysis of diagnostic test accuracy of the 4AT for delirium detection.

Methods

We searched the following electronic databases through Ovid: MEDLINE, Embase, and PsycINFO. Additional databases were searched: CINAHL (EBSCOhost), clinicaltrials.gov and Cochrane Central Register of Controlled Trials from 2011 (4AT publication) until 21 December 2019. Inclusion criteria: older adults (≥65) across any setting of care except critical care; validation study of the 4AT against a delirium reference standard (standard diagnostic criteria or validated tool). Two reviewers independently screened abstracts and papers and performed the data extraction. Pooled estimates of sensitivity and specificity were generated from a bivariate random effects model.

Results

17 studies (n = 3,701 observations) were included. Various settings including acute medicine, surgery, stroke wards and the emergency department were represented. The overall prevalence of delirium was 24.2% (95% CI 17.8–32.1%; range 10.5–61.9%). The pooled sensitivity was 0.88 (95% CI 0.80–0.93) and the pooled specificity was 0.88 (95% CI 0.82–0.92). The methodological quality of studies was mostly good.

Conclusions

The 4AT is now supported by a substantial evidence base comparable to other well-studied tools such as the Confusion Assessment Method (CAM). The strong pooled sensitivity and specificity findings for the 4AT in this meta-analysis along with its brevity and lack of need for specific training provide support for its use as an effective assessment tool for delirium.

29 Predicting Unplanned Readmission and Death After Hospital Discharge: How Do Frailty Tools Compare to Electronic Health Record Frailty Markers?

Introduction

Numerous frailty tools and definitions have been described. Amongst hospitalised patients, the validity of face-to-face instruments may be confounded by acute illness. However, patient assessment after recovery at the point of hospital discharge, or recognition of electronic health record (EHR) frailty markers, may overcome this issuep.

Methods

In a consented, prospective observational cohort study, we recruited patients ≥70 years old within 24 hours of expected discharge from the cardiology ward of the Royal Infirmary of Edinburgh. Three established frailty instruments were tested: the Fried phenotype, Short Physical Performance Battery and nurse-administered Clinical Frailty Scale (CFS). An unweighted 32-item EHR score was generated using frailty markers (e.g. falls risk, continence, cognition) recorded within mandated admission documentation. Comorbidity was assessed by count of chronic health conditions. Outcomes were a 90-day composite of unplanned readmission or death and 12-month mortality. Adjusted Cox modelling determined the hazard ratio (HR) per standard deviation increase in each frailty score.

Results

186 patients (mean age 79 ± 6 years, 64% male) were included, of whom 55 (30%) had a 90-day composite outcome, and 21 (11%) died within 12 months. All four frailty tools were moderately correlated with age and comorbidity (Pearson’s r 0.21 to 0.43, all p < 0.05). The Fried phenotype (HR 1.47, 95% CI 1.18–1.81), CFS (HR 1.24, 95% CI 1.01–1.51) and EHR score (HR 1.26, 95% CI 1.03–1.55) independently predicted 90-day readmission or death, after adjustment for age, sex and comorbidity. All frailty instruments were independent predictors of 12-month mortality, with age, sex and comorbidity losing predictive power (p > 0.05) once frailty was included in modelling.

Conclusions

At hospital discharge, the Fried phenotype and CFS added to age and comorbidity in risk prediction for future unplanned readmission or death. EHR frailty markers appeared comparable to face-to-face assessment. An automated trigger for high-risk patients using routine EHR data merits prospective evaluation.

Bio-signal data sharing security through watermarking: a technical survey

Due to smart healthcare systems highly connected information and communications technologies, sensitive medical information and records are easily transmitted over the networks. However, stealing of healthcare data is increasing crime every day to greatly impact on financial loss. In order to this, researchers are developing various cost-effective bio-signal based data hiding techniques for smart healthcare applications. In this paper, we first introduce various aspects of data hiding along with major properties, generic embedding and extraction process, and recent applications. This survey provides a comprehensive survey on data hiding techniques, and their new trends for solving new challenges in real-world applications. Then, we survey the various notable bio-signal based data hiding techniques. The summary of some notable techniques in terms of their objective, type of data hiding, methodology and database used, performance metrics, important features, and limitations are also presented in tabular form. At the end, we discuss the major issues and research directions to explore the promising areas for future research.

Probability of coronary disease and clinical outcomes in patients with type 2 myocardial infarction

Background

Type 2 myocardial infarction is common in clinical practice. However, despite these patients having a similar rate of major adverse cardiovascular events as those with atherothrombotic type 1 myocardial infarction, there is currently no consensus on how these patients should be evaluated or managed. Whether risk assessment for coronary artery disease can identify patients at increased risk of death is unclear.

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 index diagnosis was adjudicated in all patients and the likelihood of underlying coronary artery disease recorded as either low-probability, high-probability, or known based on the clinical history, risk factors and comorbidities. The adjudicators were blinded to the primary and secondary outcomes including all-cause mortality at one year.

Results

High-sensitivity cardiac troponin I concentrations were above the sex-specific 99th centile in 22% (10,360/48,282) of patients. The adjudicated diagnosis was type 1 and type 2 myocardial infarction in 55% (4,981/9,115) and 12% (1,121/9,115), respectively. Compared to patients with type 1 myocardial infarction, those with type 2 myocardial infarction were older and more likely to be women. In patients with type 2 myocardial infarction, 20% were low-probability, 55% were high-probability and 25% had known coronary artery disease. All-cause mortality was highest in patients with known or suspected coronary artery disease (22.5% and 23.3%, respectively). Those with a low-probability of coronary artery disease had the lowest event rate (8.8%), even compared to those with type 1 myocardial infarction (Figure).

Discussion

A simple clinical assessment of whether patients have a low- or high-probability of coronary artery disease is associated with future risk of death in patients with type 2 myocardial infarction. Whether incorporating this assessment into clinical practice to guide secondary prevention could improve outcomes requires prospective evaluation.

Figure 1

Funding Acknowledgement

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

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

Validation of a machine learned model to predict the diagnosis of myocardial infarction

Introduction

The myocardial-ischemic-injury-index (MI3) is a promising machine learned algorithm that predicts the likelihood of myocardial infarction in patients with suspected acute coronary syndrome. Whether this algorithm performs well in unselected patients or predicts recurrent events is unknown.

Methods

In an observational analysis from a multi-centre randomised trial, we included all patients with suspected acute coronary syndrome and serial high-sensitivity cardiac troponin I measurements without ST-segment elevation myocardial infarction. Using gradient boosting, MI3 incorporates age, sex, and two troponin measurements to compute a value (0–100) reflecting an individual's likelihood of myocardial infarction, and estimates the negative predictive value (NPV) and positive predictive value (PPV). Model performance for an index diagnosis of myocardial infarction, and for subsequent myocardial infarction or cardiovascular death at one year was determined using previously defined low- and high-probability thresholds (1.6 and 49.7, respectively).

Results

In total 20,761 of 48,282 (43%) patients (64±16 years, 46% women) were eligible of whom 3,278 (15.8%) had myocardial infarction. MI3 was well discriminated with an area under the receiver-operating-characteristic curve of 0.949 (95% confidence interval 0.946–0.952) identifying 12,983 (62.5%) patients as low-probability (sensitivity 99.3% [99.0–99.6%], NPV 99.8% [99.8–99.9%]), and 2,961 (14.3%) as high-probability (specificity 95.0% [94.7–95.3%], PPV 70.4% [69–71.9%]). At one year, subsequent myocardial infarction or cardiovascular death occurred more often in high-probability compared to low-probability patients (17.6% [520/2,961] versus 1.5% [197/12,983], P<0.001).

Conclusions

In unselected consecutive patients with suspected acute coronary syndrome, the MI3 algorithm accurately estimates the likelihood of myocardial infarction and predicts probability of subsequent adverse cardiovascular events.

Performance of MI3 at example thresholds

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Medical Research Council

GOLD SELEX: a novel SELEX approach for the development of high-affinity aptamers against small molecules without residual activity

GOLD SELEX, a novel SELEX approach has been developed that obviates the need for target immobilization for aptamer development. The approach purely relies on the affinity of the aptamers towards its target, to get detached from the gold nanoparticle (GNP) surface (weak attraction) after binding with its target. Thus, only the completely detached aptamers are selected for the next round of SELEX. This, in-process, also addresses the issue of residual binding and thus improves the sensitivity of the developed aptamers. As a proof of concept for establishing the utility of the approach for small molecules, we have developed aptamers against dichlorvos (DV), a pesticide in just 8 rounds. Using these aptamer candidates, we have developed an aptamer-NanoZyme (GNP having peroxidase mimic activity) based colorimetric assay. The developed aptamer displayed high affinity (K_d in sub micromolar range) and selectivity for DV. The developed assay could detect as low as 15 μM DV. The best-performing aptamer was also able to work in real samples like river water and commercial apple juice. The GOLD SELEX approach developed in this study, we believe, can act as a template for future SELEX strategy development and can replace the conventional SELEX strategy.

Raffinose and Hexose Sugar Content During Germination Are Related to Infrared Thermal Fingerprints of Primed Onion (Allium cepa L.) Seeds

Priming is used to increase vigor, germination synchronization, seedling growth, and field establishment by advancing metabolic processes within seeds. Seed respiration is a good indicator of the metabolic processes that lead to transition toward germination. Onion seeds (cv. Pusa Ridhi) subjected to osmopriming (-1.5 MPa PEG6000 for 7 days), magnetopriming (100 mT for 30 min) and halopriming (150 mM KNO₃ for 6 days), were evaluated at different times of imbibition to study the emergence index and respiration indices such as infrared thermal fingerprint, CO₂ evolution rate, cytochrome c oxidase activity, and soluble sugars profile. Haloprimed seeds exhibited 42.5% higher emergence index as compared to unprimed control. Primed and unprimed seeds showed negative values for relative temperature (ΔT) (difference in temperature of seed and its immediate environment). Haloprimed seeds had the lowest values (-4.1 to -2.3°C) compared to other priming treatments over the germination period. Soluble sugars like raffinose, sucrose, glucose, and fructose contents were monitored and it was observed that en masse raffinose, glucose, and fructose levels were (17.5-59.9%) lower in haloprimed seeds over control. A positive correlation (r ² = 0.504^∗∗) was derived between the amount of these sugars and ΔT. Seed respiration, measured as CO₂ evolution rate was more for haloprimed seeds that indicated that these soluble sugars were used as respiratory substrates. Significantly higher cytochrome c oxidase activity (40.7-89.8% and 12.5-66.6%) was observed in all primed seeds at 28 and 36 h, respectively. Among the various seed priming methods, halopriming proved to be the most effective priming treatment in onion seeds as evidenced by the higher respiration indices that resulted in faster metabolic rate and emergence index.

Role of structures in the masticator space in selecting patients with resectable T4b oral cancer: findings from a survival analysis

Oral squamous cell cancers involving the masticatory space are staged as unresectable cancers and their treatment is difficult. Curative treatment with extensive surgery followed by adjuvant therapy is one of the treatment options. In this retrospective study, the survival of 123 patients (93 with T4a cancers, 30 with T4b cancers), treated during the period August 2009 to August 2015, was evaluated. The majority had bucco-alveolar cancers (62.6%), were male (61.8%), and were tobacco users (76.4%). The select group of T4b oral cancer patients were treated with surgery, which included infratemporal fossa clearance in all 30 patients, followed by adjuvant therapy. The masseter was the most commonly involved masticatory muscle, and 24 patients had fewer than three involved structures. Free margins were obtained in 90.2% of cases; 41.5% of cases were node-positive. One hundred and four patients (84.6%) completed adjuvant treatment. The median follow-up was 42 months. For node-negative patients with T4a and T4b cancers, the 5-year overall survival was 59% and 50.2%, respectively (P= 0.62), and 5-year disease-free survival was 64.6% and 53.5%, respectively (P= 0.01). In conclusion, the select group of patients with T4b oral cancers and less than three masticatory space structures involved had comparable outcomes to those with T4a cancers after treatment with surgery and adjuvant radiotherapy.

P1695Incidence and outcomes of unstable angina compared to non-ST elevation myocardial infarction

Objective

Assess the incidence and compare characteristics and outcome of unstable angina (UA) and Non-ST-Elevation myocardial infarction (NSTEMI)

Design

Two independent prospective multicenter diagnostic studies (Advantageous Predictors of Acute Coronary Syndromes Evaluation (APACE) and High-Sensitivity Troponin in the Evaluation of Patients With Acute Coronary Syndrome (High-STEACS)) enrolling patients with acute chest discomfort presenting to the emergency department. Central adjudication of the final diagnosis was done by two independent cardiologists using all clinical information including serial measurements of high-sensitivity cardiac troponin (hs-cTn). All-cause death and future non-fatal MI were assessed at 30-days and 1-year.

Results

8992 patients were enrolled at 11 centres. UA was adjudicated in 366/4122 (8.9%) and 137/4870 (2.8%) patients in APACE and High-STEACS, respectively, and NSTEMI in 622 (15.1%) and 651 (13.4%). Coronary artery disease was pre-existing in 73% and 76% of patients with unstable angina. At 30-days, all-cause mortality in UA was substantially lower as compared to NSTEMI (0.5% versus 3.7%, p=0.002 in APACE, 0.7% versus 7.4%, p=0.004 in High-STEACS). Similarly, at 1-year in UA all-cause mortality was 3.3% [95% CI 1.2–5.3] vs 10.4% [7.9–12.9] in APACE, and 5.1% [0.7–9.5] vs 22.9% [19.3–26.4] in High-STEACS, and similar to non-cardiac chest pain (NCCP). In contrast, future non-fatal MI in APACE was comparable in UA and NSTEMI (11.2%, [7.8–14.6] and 7.9%, [5.7–10.2]), and higher than in NCCP (0.6%, [0.2–1.0]).

1-year survival free from future AMI

Conclusions

The incidence and the mortality of UA is substantially lower than that of NSTEMI, while the rate of future non-fatal MI is similar.

Acknowledgement/Funding

Swiss National Science Foundation, Swiss Heart Foundation, Cardiovascular Research Foundation Basel, British Heart Foundation Project Grants, Butler S

Influence of physical activity on cardiac autonomic control in patients with dyslipidaemia

The objective of this study was to compare the cardiac autonomic control of dyslipidaemia patients engaged in different levels of physical activity and to determine the predictive ability of physical activity for cardiac autonomic dysfunction in these patients. This study also aimed to compare the cardiac autonomic control of dyslipidaemia patients and healthy adults. 52 patients (age: 49.1±4.53 years) with dyslipidaemia were recruited along with 16 healthy adults. Physical activity levels were assessed by International Physical Activity Questionnaire, and subjects were divided into three categories – low, moderate, and high physical activity. Heart rate variability (HRV) analysis was performed for obtaining time and frequency domain parameters. Presence of cardiac autonomic dysfunction was defined as standard deviation of N-N intervals <44 ms. HRV parameters were compared between 3 groups of dyslipidaemia patients and healthy controls. Predictive ability of physical activity for cardiac autonomic dysfunction in dyslipidaemia was evaluated after adjusting clinical covariates. There was a significant difference between low-frequency power (cardiac sympathetic control), and ratio of low- and high-frequency (HF) power (sympatho-vagal balance) in low versus moderate physical activity group and low versus high physical activity group (P<0.001). Significant differences were also observed for HFnu power (cardiac vagal activity) and total power between the dyslipidaemia groups. Physical activity was found to be a significant (P=0.03), independent predictor of cardiac autonomic dysfunction in dyslipidaemia patients. Findings of the present study suggest that cardiac autonomic profile of dyslipidaemia patients with different physical activity levels varied significantly. Dyslipidaemia patients engaged in moderate and high physical activity demonstrated significantly less sympathetic activity and better sympatho-vagal balance than those engaged in low levels of physical activity; also, vagal cardiac control was significantly greater in high physical activity group. Lower levels of physical activity determined the presence of cardiac autonomic dysfunction in these patients at an optimal cut-off value of ≤1,558 Metabolic Equivalent of Tasks- min/week.

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

P5013Trends in hospitalised cardiac arrest outcomes over 25 years in Scotland

Introduction

Cardiac arrest is a major healthcare burden; survival has historically been poor. Contemporary therapies have been associated with improvements in out-of-hospital cardiac arrest survival in other healthcare systems.

Purpose

To determine temporal trends and predictors of 30-day and overall survival in patients with cardiac arrest who survive to hospital admission in Scotland.

Methods

We conducted a consecutive individual patient linkage study using data from the Scottish Morbidity Records held by the Information Services Division, National Health Service Scotland. We identified all patients who had an index cardiac arrest hospitalisation from 1st January 1990 to 31st December 2014. The primary outcome was 30-day mortality. Generalised additive models were used to estimate temporal trends. Year of admission was the primary explanatory variable, adjusted for age, sex, comorbidities (stroke, myocardial infarction, heart failure), Scottish Index of Multiple Deprivation (SIMD, a national deprivation score), and angiography within 30 days of admission. Cox regression models were constructed for overall mortality, adjusting for the above variables.

Results

In total, 47,692 patients had an index hospitalisation with cardiac arrest in Scotland between 1990 and 2014. The mean age was 69±16 years; 45% (n=21,257) were female. Most patients (n=24,867, 52.4%) were in top two SIMD quintiles (greater deprivation). Incidence was lowest in 1990 (27 per 100,000 population), rising until 1998 (47 per 100,000) before declining (mean 30 per 100,000 for 2010–2014) (Figure 1A). Overall rates of angiography and PCI at 30 days were low (5.4% and 3.1% respectively), albeit higher in more recent years (14.1% and 9.6% respectively for 2010–2014).

Thirty-day mortality was high but decreased over time (73.7% from 1990–1994 to 63.1% from 2010–2014, p<0.001). This effect persisted after adjustment for covariates. The predicted 30-day mortality for a 69 year old patient was highest in 1990 (75%, 95% confidence interval [CI] 73–77%) and lowest in 2014 (66%, 95% CI 64–68%) (Figure 1B). Age, heart failure and greater deprivation were other independent predictors of 30-day mortality. In contrast, previous myocardial infarction and angiography within 30 days were predictors of reduced 30-day mortality. On Cox regression analysis, age (hazard ratio [HR] 1.15, 95% CI 1.14–1.16 per 10 years) and heart failure (HR 1.11, 95% CI 1.08–1.14) were independent predictors of overall mortality. Thirty-day angiography (HR 0.29, 95% CI 0.28–0.31) was the strongest independent predictor of survival, likely reflecting selection bias, in addition to year of admission, previous myocardial infarction and less deprivation.

Temporal trends in cardiac arrest

Conclusions

Hospital episodes with cardiac arrest in Scotland peaked in the late 1990s and have since fallen. Thirty-day mortality remains high, with an improvement over time that is independent of baseline patient characteristics.

3325Incidence, outcomes and microbiology in patients with infective endocarditis

Introduction

Despite recent improvements in management, infective endocarditis remains associated with high morbidity and mortality. Over the last few decades, several factors have impacted on both the incidence and outcomes following infective endocarditis.

Purpose

Using a national linkage approach, we describe the changing age- and sex-stratified incidence and outcomes of infective endocarditis in Scotland over the last 25 years.

Methods

We conducted a consecutive retrospective individual patient linkage study across multiple national databases. Using data extracted from the Scottish hospital discharge dataset held by the Information Services Division of NHS National Services Scotland, we extracted episodes for all patients aged 20 years or older who were admitted with infective endocarditis between January 1, 1990, and December 31, 2014 in Scotland, UK. Patient episodes with infective endocarditis were linked to national prescribing and microbiology databases. The primary outcome was 1-year mortality following the index presentation. Generalised additive models were constructed to estimate the crude and age- and sex-stratified incidence rates (using a poison distribution) as well as trends in mortality (using a binomial distribution) adjusted for age, sex and comorbidity.

Results

Across 12,446 individual patients, there were a total of 12,667 hospitalisations (mean age 68±17 years, 55% females) with infective endocarditis using a 5-year look back period. The estimated crude rate of hospitalisation increased from 7.38 per 100,000 (95% CI 6.58 to 8.28) in 1990 to 15.09 per 100,000 (95% CI 13.90 to 16.39) in 2014 (p<0.001). Over the period of the study, 31% (3,877/12,667) of people admitted to hospital with infective endocarditis died within one year of admission. Case fatality fell markedly in both men and women from 1990 to 2014 (Figure). Microbiology was status was available for 34% of all hospitalisations with staphylococcus cultures associated with worse outcomes.

Conclusions

Despite the crude incidence of infective endocarditis doubling over the last 25 years and case fatality remaining high, the risk of death has markedly fallen over the last two decades. Staphylococcus cultures remain an independent marker of poor prognosis in this cohort.

Acknowledgement/Funding

British Heart Foundation

P1578Outcomes in patients with renal impairment and myocardial injury or infarction identified by high-sensitivity cardiac troponin testing: a secondary analysis of the High-STEACS trial

Background

Patients with renal impairment are at increased risk of myocardial infarction (MI), but the interpretation of cardiac troponin is challenging in this setting. The use of high-sensitivity cardiac troponin (hs-cTn) assays increases the detection of myocardial injury, yet may contribute to uncertainty in the diagnosis of MI in those with renal impairment.

Purpose

To describe the diagnosis and outcomes of patients with myocardial injury or infarction identified using a hs-cTnI assay, stratified by renal function.

Methods

In a pre-specified secondary analysis of a stepped-wedge cluster-randomised controlled trial, we identified consecutive patients with a hs-cTnI concentration greater than the sex-specific 99th centile between June 2013 and March 2016. The diagnoses of type 1 or type 2 MI were adjudicated and classified according to the 4th Universal Definition of Myocardial Infarction. Renal impairment was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73m2.The primary outcome of type 1 or type 4b MI or cardiovascular death was compared in patients with and without renal impairment at 1 year.

Results

A measure of renal function was available in 47,334 (98.0%) patients, of whom 7,933 (16.8%) had renal impairment (mean age 76±12 years; 54% female). Plasma hs-cTnI concentrations were >99th centile in 47.9% (3,800/7,933) of patients with renal impairment and 16.3% (6,439/39,401) of patients with normal renal function. In those with and without renal impairment, the adjudicated diagnosis was type 1 MI in 35.2% (1,336/3,800) and 55.8% (3,596/6,439) of patients, and type 2 MI in 12.6% (480/3,800) and 9.7% (626/6,439) of patients, respectively (P<0.001 for both). In patients with hs-cTnI concentrations >99th centile, the primary outcome occurred in 24.9% (945/3,800) of patients with renal impairment, compared to 12.1% (779/6,439) of patients with normal renal function (P<0.001). In patients with type 1 MI, the primary outcome occurred in 32.6% (436/1,336) of those with renal impairment and 11.7% (419/3,596) of those without (P<0.001). In patients with type 2 MI, the primary outcome occurred in 20.4% (98/480) and 9.9% (62/626) of patients with and without renal impairment, respectively (P<0.001).

Conclusion

Almost half of all patients with suspected acute coronary syndrome and renal impairment have hs-cTnI concentrations greater than the sex-specific 99th centile. Whilst only one in three had a diagnosis of type 1 MI, an elevated troponin concentration was associated with a poorer prognosis in those with concomitant renal impairment compared to those without, irrespective of the index diagnosis.

Acknowledgement/Funding

British Heart Foundation

P1731High-sensitivity troponin with sex-specific thresholds in suspected acute coronary syndrome

Background/Introduction

Major disparities between women and men in the diagnosis, management and outcome of acute coronary syndrome are well recognised. Whether sex-specific diagnostic thresholds for myocardial infarction will address these differences is uncertain.

Purpose

To evaluate the impact of implementing a high-sensitivity cardiac troponin I (hs-cTnI) assay with sex-specific diagnostic thresholds for myocardial infarction in women and men with suspected acute coronary syndrome.

Methods

In a stepped-wedge, cluster-randomized controlled trial across ten hospitals we evaluated the implementation of a hs-cTnI assay in 48,282 (47% women) consecutive patients with suspected acute coronary syndrome. During a validation phase the hs-cTnI assay results were suppressed and a contemporary cTnI assay with a single threshold was used to guide care. Myocardial injury was defined as any hs-cTnI concentration >99th centile of 16 ng/L in women and 34 ng/L in men. The primary outcome was myocardial infarction after the initial presentation or cardiovascular death at 1 year. In this prespecified analysis, we evaluated outcomes in men and women before and after implementation of the hs-cTnI assay.

Results

Use of the hs-cTnI assay with sex-specific thresholds increased myocardial injury in women by 42% (from 3,521 (16%) to 4,991 (22%)) and by 6% in men (from 5,068 (20%) to 5,369 (21%)). Whilst treatment increased in both sexes, women with myocardial injury remained less likely than men to undergo coronary revascularisation (15% versus34%), or to receive dual anti-platelet (26% versus43%), statin (16% versus26%) or other preventative therapies (P<0.001 for all). The primary outcome occurred in 18% (369/2,072) and 17% (488/2,919) of women with myocardial injury during the validation and implementation phase respectively (adjusted hazard ratio 1.11, 95% confidence interval 0.92 to 1.33), compared to 18% (370/2,044) and 15% (513/3,325) of men (adjusted hazard ratio 0.85, 95% confidence interval 0.71 to 1.01).

Patient management

Conclusion

Use of sex-specific thresholds identified five-times more additional women than men with myocardial injury, such that the proportion of women and men with myocardial injury is now similar. Despite this increase, women received approximately half the number of treatments for coronary artery disease as men and their outcomes were not improved.

Acknowledgement/Funding

The British Heart Foundation