External validation of a rapid algorithm using high-sensitivity troponin assay results for evaluating patients with suspected acute myocardial infarction.

OBJECTIVE: We sought to validate the clinical performance of a rapid assessment pathway incorporating the Siemens Atellica IM high sensitivity cardiac troponin I (hs-cTnI) assay in patients presenting to the emergency department (ED) with suspected acute myocardial infarction (AMI). METHODS: This was a multicentre prospective observational study of adult ED patients presenting to five Australian hospitals between November 2020 and September 2021. Participants included those with symptoms of suspected AMI (without ST-segment elevation MI on presentation ECG). The Siemen's Atellica IM hs-cTnI laboratory-based assay was used to measure troponin concentrations at admission and after 2-3 hours and cardiologists adjudicated final diagnoses. The HighSTEACS diagnostic algorithm was evaluated, incorporating hs-cTnI concentrations at presentation and absolute changes within the first 2 to 3 hours. The primary outcome was index AMI, including type 1 or 2 non-ST segment elevation MI (NSTEMI) or ST-elevation MI (STEMI) following presentation. 30-day major adverse cardiac outcomes (including AMI, urgent revascularisation or cardiac death) were also reported. The trial was registered with the Australian and New Zealand Clinical Trials Registry. RESULTS: 1994 patients were included. The average age was 56.2 years (SD=15.6), and 44.9% were women. 118 (5.9%) patients had confirmed index AMI. The 2-hour algorithm defined 61.3% of patients as low risk. Sensitivity was 99.1% (94.0%-99.9%) and negative predictive value was 99.9% (99.3%-100%). 24.4% of patients were deemed intermediate risk. When applying the parameters for high risk, 252 (14.3%) were identified, with a specificity of 91.5% (88.7%-93.6%) and a PPV of 42.0% (35.6-48.7%). CONCLUSIONS: A 2-hour algorithm based on the HighSTEACS strategy using the Siemens Atellica IM hs-cTnI laboratory-based assay enables safe and efficient risk assessment of emergency patients with suspected AMI. TRIAL REGISTRATION NUMBER: ACTRN12621000053820.

Single High-Sensitivity Point-of-Care Whole-Blood Cardiac Troponin I Measurement to Rule Out Acute Myocardial Infarction at Low Risk.

BACKGROUND: High-sensitivity cardiac troponin (hs-cTn) laboratory assays are used to rule out myocardial infarction (MI) on presentation, but prolonged result turnaround times can delay patient management. Our primary aim was to identify patients at low risk of index MI using a rapid point-of-care (POC) whole-blood hs-cTnI assay at presentation with potential early patient discharge. METHODS: Consecutive patients presenting to the emergency department from 2 prospective observational studies with suspected acute coronary syndrome were enrolled. A POC hs-cTnI assay (Atellica VTLi) threshold using whole blood at presentation, which resulted in a negative predictive value of ≥99.5% and sensitivity of >99% for index MI, was derived (SEIGE [Safe Emergency Department Discharge Rate]) and validated with plasma (SAMIE [Suspected Acute Myocardial Infarction in Emergency]). Event adjudications were established with hs-cTnI assay results from routine clinical care. The primary outcome was MI at 30 days. RESULTS: A total of 1086 patients (8.1% with MI) were enrolled in a US derivation cohort (SEIGE) and 1486 (5.5% MI) in an Australian validation cohort (SAMIE). A derivation whole-blood POC hs-cTnI concentration of <4 ng/L provided a sensitivity of 98.9% (95% CI, 93.8%-100%) and negative predictive value of 99.5% (95% CI, 97.2%-100%) for ruling out MI. In the validation cohort, the sensitivity was 98.8% (95% CI, 93.3%-100%), and negative predictive value was 99.8% (95% CI, 99.1%-100%); 17.8% and 41.8%, respectively, were defined as low risk for discharge. The 30-day adverse cardiac events were 0.1% (n=1) for SEIGE and 0.8% (n=5) for SAMIE. CONCLUSIONS: A POC whole-blood hs-cTnI assay permits accessible, rapid, and safe exclusion of MI and may expedite discharge from the emergency department. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04772157. URL: https://www.australianclinicaltrials.gov.au/anzctr_feed/form; Unique identifier: 12621000053820.

Emergency department presentations during the COVID-19 pandemic in Queensland (to June 2021): interrupted time series analysis.

OBJECTIVES: To assess emergency department (ED) presentation numbers in Queensland during the coronavirus disease 2019 (COVID-19) pandemic to mid-2021, a period of relatively low COVID-19 case numbers. DESIGN: Interrupted time series analysis. SETTING: All 105 Queensland public hospital EDs. MAIN OUTCOME MEASURES: Numbers of ED presentations during the COVID-19 lockdown period (11 March 2020 - 30 June 2020) and the period of easing restrictions (1 July 2020 - 30 June 2021), compared with pre-pandemic period (1 January 2018 - 10 March 2020), overall (daily numbers) and by Australasian Triage Scale (ATS; daily numbers) and selected diagnostic categories (cardiac, respiratory, mental health, injury-related conditions) and conditions (stroke, sepsis) (weekly numbers). RESULTS: During the lockdown period, the mean number of ED presentations was 19.4% lower (95% confidence interval, -20.9% to -17.9%) than during the pre-pandemic period (predicted mean number: 5935; actual number: 4786 presentations). The magnitudes of the decline and the time to return to predicted levels varied by ATS category and diagnostic group; changes in presentation numbers were least marked for ATS 1 and 2 (most urgent) presentations, and for presentations with cardiac conditions or stroke. Numbers remained below predicted levels during the 12-month post-lockdown period for ATS 5 (least urgent) presentations and presentations with mental health problems, respiratory conditions, or sepsis. CONCLUSIONS: The COVID-19 pandemic and related public restrictions were associated with profound changes in health care use. Pandemic plans should include advice about continuing to seek care for serious health conditions and health emergencies, and support alternative sources of care for less urgent health care needs.

Facilitators and barriers for emergency department clinicians using a rapid chest pain assessment protocol: qualitative interview research.

BACKGROUND: Guideline-based processes for the assessment of chest pain are lengthy and resource intensive. The IMProved Assessment of Chest Pain Trial (IMPACT) protocol was introduced in one Australian hospital Emergency Department (ED) to more efficiently risk stratify patients. The theoretical domains framework is a useful approach to assist in identifying barriers and facilitators to the implementation of new guidelines in clinical practice. The aim of this study was to understand clinicians' perceptions of facilitators and barriers to the use of the IMPACT protocol. METHODS: Guided by the theoretical domains framework, semi-structured interviews with nine ED clinical staff (medical and nursing) were undertaken in 2016. Content analysis was conducted independently by two researchers to identify those theoretical domains that facilitated or hindered protocol use. RESULTS: Domains most often reported as fundamental to the use of the IMPACT protocol included 'social/professional role and identity', 'environmental context and resources' and 'social influences'. These factors seemingly influenced professional confidence, with participants noting 'goals' that included standardisation of practice, enhanced patient safety, and reduced need for unnecessary testing. The domain 'environmental context and resources' also contained the most noted barrier - the need to inform new members of staff regarding protocol use. Opportunities to overcome this barrier included modelling of protocol use by staff at all levels and education - both formal and informal. CONCLUSIONS: A range of domains were identified by ED staff as influencing their chest pain management behaviour. Fundamental to its use were champions/leaders that were trusted and accessible, as well as social influences (other staff within ED and other specialty areas) that enabled and supported protocol use. Research investigating the implementation and perceived use of the protocol at other sites, of varied geographical locations, is warranted.

Examining the translational success of an initiative to accelerate the assessment of chest pain for patients in an Australian emergency department: a pre-post study.

BACKGROUND: The Improved assessment of chest pain trial (IMPACT) protocol is an accelerated strategy for the risk stratification and management of patients presenting to the emergency department (ED) with chest pain. This study sought to describe the adoption, sustainability and health services implications of implementing the IMPACT protocol. METHODS: This was a study of adult patients in a large Australian tertiary hospital who had serial troponin testing commenced within the ED. Data from two periods were utilized; the pre-implementation period (8th April 2012 to 5th April 2014) and the post-implementation period (6th April 2014 to 2nd April 2016). The primary outcome was the proportion of patients undergoing accelerated care. Secondary endpoints were ED assessment time, hospital length of stay, and costs. Data were compared in the pre- and post-implementation periods. RESULTS: The proportion of patients receiving accelerated care increased from 3% in the pre- to 34% in the post-intervention period. This increase occurred rapidly after implementation of IMPACT and was sustained over a 2-year period. For patients with troponin concentrations <99th percentile, the mean ED assessment time reduced from 12.3 h in the pre- to 10.1 h in the post-implementation period. Mean hospital length of stay was similar in the pre- and post-implementation periods (82.4 and 80.9 h). The average cost of chest pain assessment reduced from $3520 pre implementation to $3204 post implementation; a $316 reduction per patient. CONCLUSIONS: The IMPACT protocol was rapidly adopted and utilised after implementation into standard care. The initial increase in the proportion of patients undergoing accelerated assessment, followed by a plateau towards the end of the study period indicate adoption and sustainability of the IMPACT protocol over a two-year period. Modest reductions in length of stay and cost were seen after implementation. Given the large number of patients investigated for chest pain, such reductions may have substantial impact on the overall healthcare system.

Key occupational stressors in the ED: an international comparison.

BACKGROUND: The ED Stressor Scale outlines 15 stressors that are of importance for ED staff. Limited research has identified how commonly such stressors occur, or whether such factors are perceived with similar importance across different hospitals. This study sought to examine the frequency or perceived severity of these 15 stressors using a multicentre cohort of emergency clinicians (nurses and physicians) in EDs in two countries (Australia and Sweden). METHOD: This was a cross-sectional survey of staff working in eight hospitals in Australia and Sweden. Data were collected between July 2016 and June 2017 (depending on local site approvals) via a printed survey incorporating the 15-item ED stressor scale. The median stress score for each item and the frequency of experiencing each event was reported. RESULTS: Events causing most distress include heavy workload, death or sexual abuse of a child, inability to provide optimum care and workplace violence. Stressors reported most frequently include dealing with high acuity patients, heavy workload and crowding. Violence, workload, inability to provide optimal care, poor professional relations, poor professional development and dealing with high-acuity patients were reported more commonly by Australian staff. Swedish respondents reported more frequent exposure to mass casualty incidents, crisis management and administrative concerns. CONCLUSIONS: Workload, inability to provide optimal care, workplace violence and death or sexual abuse of a child were consistently reported as the most distressing events across sites. The frequency with which these occurred differed in Australia and Sweden, likely due to differences in the healthcare systems.

Factors influencing physician risk estimates for acute cardiac events in emergency patients with suspected acute coronary syndrome.

BACKGROUND: Emergency physicians frequently assess risk of acute cardiac events (ACEs) in patients with undifferentiated chest pain. Such estimates have been shown to have moderate to high sensitivity for ACE but are conservative. Little is known about the factors implicitly used by physicians to determine the pretest probability of risk. This study sought to identify the accuracy of physician risk estimates for ACE in patients presenting to the ED with chest pain and to identify the demographic and clinical information emergency physicians use in their determination of patient risk. METHODS: This study used data from two prospective studies of consenting adult patients presenting to the ED with symptoms of possible acute coronary syndrome. ED physicians estimated the pretest probability of ACE. Multiple linear regression analysis was used to identify predictors of physician risk estimates. Logistic regression was used to determine whether there was a correlation between physicians' estimated risk and ACE. RESULTS: Increasing age, male sex, abnormal ECG features, heavy/crushing chest pain and risk factors were correlated with physician risk estimates. Physician risk estimates were consistently found to be higher than the expected proportion of ACE from the sampled population. CONCLUSION: Physicians systematically overestimate ACE risk. A range of factors are associated with physician risk estimates. These include factors strongly predictive of ACE, such as age and ECG characteristics. They also include other factors that have been shown to be unreliable predictors of ACE in an ED setting, such as typicality of pain and risk factors.

Detectable High-Sensitivity Cardiac Troponin within the Population Reference Interval Conveys High 5-Year Cardiovascular Risk: An Observational Study.

BACKGROUND: Increased cardiac troponin I or T detected by high-sensitivity assays (hs-cTnI or hs-cTnT) confers an increased risk of adverse prognosis. We determined whether patients presenting with putatively normal, detectable cTn concentrations [> limit of detection and < upper reference limit (URL)] have increased risk of major adverse cardiovascular events (MACE) or all-cause mortality. METHODS: A prospective 5-year follow-up of patients recruited in the emergency department with possible acute coronary syndrome (ACS) and cTn concentrations measured with hs-cTnI (Abbott) and hs-cTnT (Roche) assays. Cox regression models were generated with adjustment for covariates in those without MACE on presentation. Hazard ratios (HRs) for hs-cTn were calculated relative to the HRs at the median concentration. RESULTS: Of 1113 patients, 836 were without presentation MACE. Of these, 138 incurred a MACE and 169 died during a median 5.8-year follow-up. HRs for MACE at the URLs were 2.3 (95% CI, 1.7-3.2) for hs-cTnI and 1.8 (95% CI, 1.3-2.4) for hs-cTnT. Corresponding HRs for mortality were 1.7 (95% CI, 1.2-2.2) for hs-cTnI and 2.3 (95 % CI, 1.7-3.1) for hs-cTnT. The HR for MACE increased with increasing hs-cTn concentration similarly for both assays, but the HR for mortality increased at approximately twice the rate for hs-cTnT than hs-cTnI. Patients with hs-cTnI ≥10 ng/L or hs-cTnT ≥16 ng/L had the same percentage of MACE at 5-year follow-up (33%) as patients with presentation MACE. CONCLUSIONS: Many patients with ACS ruled out and putatively normal but detectable hs-cTnI concentrations are at similar long-term risk as those with MACE. hs-cTnT concentrations are more strongly associated with 5-year mortality than hs-cTnI.

Clinical chemistry score versus high-sensitivity cardiac troponin I and T tests alone to identify patients at low or high risk for myocardial infarction or death at presentation to the emergency department.

BACKGROUND: Testing for high-sensitivity cardiac troponin (hs-cTn) may assist triage and clinical decision-making in patients presenting to the emergency department with symptoms of acute coronary syndrome; however, this could result in the misclassification of risk because of analytical variation or laboratory error. We sought to evaluate a new laboratory-based risk-stratification tool that incorporates tests for hs-cTn, glucose level and estimated glomerular filtration rate to identify patients at risk of myocardial infarction or death when presenting to the emergency department. METHODS: We constructed the clinical chemistry score (CCS) (range 0-5 points) and validated it as a predictor of 30-day myocardial infarction (MI) or death using data from 4 cohort studies involving patients who presented to the emergency department with symptoms suggestive of acute coronary syndrome. We calculated diagnostic parameters for the CCS score separately using high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT). RESULTS: For the combined cohorts (n = 4245), 17.1% of participants had an MI or died within 30 days. A CCS score of 0 points best identified low-risk participants: the hs-cTnI CCS had a sensitivity of 100% (95% confidence interval [CI] 99.5%-100%), with 8.9% (95% CI 8.1%-9.8%) of the population classified as being at low risk of MI or death within 30 days; the hs-cTnT CCS had a sensitivity of 99.9% (95% CI 99.2%-100%), with 10.5% (95% CI 9.6%-11.4%) of the population classified as being at low risk. The CCS had better sensitivity than hs-cTn alone (hs-cTnI < 5 ng/L: 96.6%, 95% CI 95.0%-97.8%; hs-cTnT < 6 ng/L: 98.2%, 95% CI 97.0%-99.0%). A CCS score of 5 points best identified patients at high risk (hs-cTnI CCS: specificity 96.6%, 95% CI 96.0%-97.2%; 11.2% [95% CI 10.3%-12.2%] of the population classified as being at high risk; hs-cTnT CCS: specificity 94.0%, 95% CI 93.1%-94.7%; 13.1% [95% CI 12.1%-14.1%] of the population classified as being at high risk) compared with using the overall 99th percentiles for the hs-cTn assays (specificity of hs-cTnI 93.2%, 95% CI 92.3-94.0; specificity of hs-cTnT 73.8%, 95% CI 72.3-75.2). INTERPRETATION: The CCS score at the chosen cut-offs was more sensitive and specific than hs-cTn alone for risk stratification of patients presenting to the emergency department with suspected acute coronary syndrome. Study registration: ClinicalTrials.gov, nos. NCT01994577; NCT02355457.

Diagnostic Accuracy of a New High-Sensitivity Troponin I Assay and Five Accelerated Diagnostic Pathways for Ruling Out Acute Myocardial Infarction and Acute Coronary Syndrome.

STUDY OBJECTIVE: This diagnostic accuracy study describes the performance of 5 accelerated chest pain pathways, calculated with the new Beckman's Access high-sensitivity troponin I assay. METHODS: High-sensitivity troponin I was measured with presentation and 2-hour blood samples in 1,811 patients who presented to an emergency department (ED) in Australia. Patients were classified as being at low risk according to 5 rules: modified accelerated diagnostic protocol to assess patients with chest pain symptoms using troponin as the only biomarker (m-ADAPT), the Emergency Department Assessment of Chest Pain Score (EDACS) pathway, the History, ECG, Age, Risk Factors, and Troponin (HEART) pathway, the No Objective Testing Rule, and the new Vancouver Chest Pain Rule. Endpoints were 30-day acute myocardial infarction and acute coronary syndrome. Measures of diagnostic accuracy for each rule were calculated. RESULTS: Data included 96 patients (5.3%) with acute myocardial infarction and 139 (7.7%) with acute coronary syndrome. The new Vancouver Chest Pain Rule and No Objective Testing Rule had high sensitivity for acute myocardial infarction (100%; 95% confidence interval [CI] 96.2% to 100% for both) and acute coronary syndrome (98.6% [95% CI 94.9% to 99.8%] and 99.3% [95% CI 96.1% to 100%]). The m-ADAPT, EDACS, and HEART pathways also yielded high sensitivity for acute myocardial infarction (96.9% [95% CI 91.1% to 99.4%] for m-ADAPT and 97.9% [95% CI 92.7% to 99.7%] for EDACS and HEART), but lower sensitivity for acute coronary syndrome (≤95.0% for all). The m-ADAPT, EDACS, and HEART rules classified more patients as being at low risk (64.3%, 62.5%, and 49.8%, respectively) than the new Vancouver Chest Pain Rule and No Objective Testing Rule (28.2% and 34.5%, respectively). CONCLUSION: In this cohort with a low prevalence of acute myocardial infarction and acute coronary syndrome, using the Beckman's Access high-sensitivity troponin I assay with the new Vancouver Chest Pain Rule or No Objective Testing Rule enabled approximately one third of patients to be safely discharged after 2-hour risk stratification with no further testing. The EDACS, m-ADAPT, or HEART pathway enabled half of ED patients to be rapidly referred for objective testing.

Psychological Predictors of Postconcussive Symptoms Following Traumatic Injury.

OBJECTIVE: To determine the contribution of demographics, injury type, pain, and psychological factors on postconcussive symptoms. SETTING AND PARTICIPANTS: Recently injured (n = 54) and noninjured (n = 184) adults were recruited from a hospital emergency department or the community. Thirty-eight individuals met the diagnostic criteria for a mild traumatic brain injury and 16 individuals received treatment for a minor traumatic non-brain injury. MAIN MEASURES: Standardized tests were administered to assess 4 postconcussion symptom types and theorized predictors including a "physiogenic" variable (injury type) and "psychogenic" variables (symptoms of anxiety, depression, and stress) within 1 month of the injury. RESULTS: In the injured sample, after controlling for injury type, demographics, and pain (chronic and current), a hierarchical regression analysis revealed that the combination of psychological symptoms predicted affective (F10,42 = 2.80, P = .009, Rchange = 0.27) but not other postconcussion symptoms types. Anxiety (ß = .48), stress (ß = .18), and depression (ß = -.07) were not statistically significant individual predictors (P > .05). Cognitive and vestibular postconcussion symptoms were not predicted by the modeled factors, somatic sensory postconcussion symptoms were predicted by demographic factors only, and the pattern of predictors for the symptom types differed for the samples. CONCLUSIONS: Traditional explanatory models do not account for these findings. The predictors are multifactorial, different for injured versus noninjured samples, and symptom specific.

Rapid Rule-out of Acute Myocardial Infarction With a Single High-Sensitivity Cardiac Troponin T Measurement Below the Limit of Detection: A Collaborative Meta-analysis.

Background: High-sensitivity assays for cardiac troponin T (hs-cTnT) are sometimes used to rapidly rule out acute myocardial infarction (AMI). Purpose: To estimate the ability of a single hs-cTnT concentration below the limit of detection (<0.005 µg/L) and a nonischemic electrocardiogram (ECG) to rule out AMI in adults presenting to the emergency department (ED) with chest pain. Data Sources: EMBASE and MEDLINE without language restrictions (1 January 2008 to 14 December 2016). Study Selection: Cohort studies involving adults presenting to the ED with possible acute coronary syndrome in whom an ECG and hs-cTnT measurements were obtained and AMI outcomes adjudicated during initial hospitalization. Data Extraction: Investigators of studies provided data on the number of low-risk patients (no new ischemia on ECG and hs-cTnT measurements <0.005 µg/L) and the number who had AMI during hospitalization (primary outcome) or a major adverse cardiac event (MACE) or death within 30 days (secondary outcomes), by risk classification (low or not low risk). Two independent epidemiologists rated risk of bias of studies. Data Synthesis: Of 9241 patients in 11 cohort studies, 2825 (30.6%) were classified as low risk. Fourteen (0.5%) low-risk patients had AMI. Sensitivity of the risk classification for AMI ranged from 87.5% to 100% in individual studies. Pooled estimated sensitivity was 98.7% (95% CI, 96.6% to 99.5%). Sensitivity for 30-day MACEs ranged from 87.9% to 100%; pooled sensitivity was 98.0% (CI, 94.7% to 99.3%). No low-risk patients died. Limitation: Few studies, variation in timing and methods of reference standard troponin tests, and heterogeneity of risk and prevalence of AMI across studies. Conclusion: A single hs-cTnT concentration below the limit of detection in combination with a nonischemic ECG may successfully rule out AMI in patients presenting to EDs with possible emergency acute coronary syndrome. Primary Funding Source: Emergency Care Foundation.

Characteristics and occurrence of type 2 myocardial infarction in emergency department patients: a prospective study.

OBJECTIVE: To identify differences in prevalence, demographics, clinical features and outcomes for type 1 myocardial infarction (T1MI) and type 2 myocardial infarction (T2MI) in a cohort of patients presenting to the Emergency Department (ED) with chest pain. METHODS: This was a post hoc analysis of data collected from two prospective studies. Data were collected between November 2008 and February 2011 for the first study, and between February 2011 and March 2014 for the second. Participants were patients presenting to the ED with symptoms suggestive of acute coronary syndrome (ACS). The outcome was 30-day diagnosis; classified into T1MI, T2MI or non-MI. Descriptive statistics were used to compare the demographics, clinical history and presenting symptoms across diagnoses (T1MI, T2MI and non-MI). Cumulative mortality over 1 year was compared for T1MI and T2MI. RESULTS: 147 patients (6.3%; 95% CI 5.3% to 7.3%) were classified as T1MI and 52 (2.2%; 95% CI 1.7% to 2.9%) were classified as T2MI. T2MIs were more likely to be female (OR 4.71, 95% CI 2.28 to 9.76), have an abnormal but non-ischaemic ECG (OR 2.95, 95% CI 1.45 to 6.00), report prior hypertension (OR 2.83, 95% CI 1.35 to 6.12), have tachycardia (OR 9.26, 95% CI 3.08 to 30.77) and pain at rest (OR 3.04, 95% CI 1.28 to 8.02) compared with T1MI. One-year mortality was similar between T1MI and T2MI (9% and 14.6%, respectively, p=0.37). CONCLUSIONS: T2MIs comprised one quarter of all MIs diagnosed in the ED. Among patients presenting to the ED with symptoms of ACS, symptoms do not allow clinicians to reliably differentiate patients with T1MI and T2MI. Prior hypertension, tachycardia and abnormal non-ischaemic ECGs are seen more often in T2MI compared with T1MI. One-year mortality was substantial in patients with T1MI and T2MI, but low power precludes conclusions about mortality differences between groups.

Assessment of the European Society of Cardiology 0-Hour/1-Hour Algorithm to Rule-Out and Rule-In Acute Myocardial Infarction.

BACKGROUND: The new European Society of Cardiology guidelines to rule-in and rule-out acute myocardial infarction (AMI) in the emergency department include a rapid assessment algorithm based on high-sensitivity cardiac troponin and sampling at 0 and 1 hour. Emergency department physicians require high sensitivity to confidently rule-out AMI, whereas cardiologists aim to minimize false-positive results. METHODS: High-sensitivity troponin I and T assays were used to measure troponin concentrations in patients presenting with chest-pain symptoms and being investigated for possible acute coronary syndrome at hospitals in New Zealand, Australia, and Canada. AMI outcomes were independently adjudicated by at least 2 physicians. The European Society of Cardiology algorithm performance with each assay was assessed by the sensitivity and proportion with AMI ruled out and the positive predictive value and proportion ruled-in. RESULTS: There were 2222 patients with serial high-sensitivity troponin T and high-sensitivity troponin I measurements. The high-sensitivity troponin T algorithm ruled out 1425 (64.1%) with a sensitivity of 97.1% (95% confidence interval [CI], 94.0%-98.8%) and ruled-in 292 (13.1%) with a positive predictive value of 63.4% (95% CI, 57.5%-68.9%).The high-sensitivity troponin I algorithm ruled out 1205 (54.2%) with a sensitivity of 98.8% (95% CI, 96.4%-99.7%)) and ruled-in 310 (14.0%) with a positive predictive value of 68.1% (95% CI, 62.6%-73.2%). CONCLUSIONS: The sensitivity of the European Society of Cardiology rapid assessment 0-/1-hour algorithm to rule-out AMI with high-sensitivity troponin may be insufficient for some emergency department physicians to confidently send patients home. These algorithms may prove useful to identify patients requiring expedited management. However, the positive predictive value was modest for both algorithms.

Direct Comparison of 2 Rule-Out Strategies for Acute Myocardial Infarction: 2-h Accelerated Diagnostic Protocol vs 2-h Algorithm.

BACKGROUND: We compared 2 high-sensitivity cardiac troponin (hs-cTn)-based 2-h strategies in patients presenting with suspected acute myocardial infarction (AMI) to the emergency department (ED): the 2-h accelerated diagnostic protocol (2h-ADP) combining hs-cTn, electrocardiogram, and a risk score, and the 2-h algorithm exclusively based on hs-cTn concentrations and their absolute changes. METHODS: Analyses were performed in 2 independent diagnostic cohorts [European Advantageous Predictors of Acute Coronary Syndrome Evaluation (APACE) study, Australian-New Zealand 2-h Accelerated Diagnostic Protocol to Assess patients with chest Pain symptoms using contemporary Troponins as the only biomarker (ADAPT) study] employing hs-cTnT (Elecsys) and hs-cTnI (Architect). The final diagnosis was adjudicated by 2 independent cardiologists. RESULTS: AMI was the final diagnosis in 16.5% (95% CI, 14.6%-18.6%) of the 1372 patients in APACE, and 12.6% (95% CI, 10.7%-14.7%) of 1153 patients in ADAPT. The negative predictive value (NPV) and sensitivity for AMI were very high and comparable with both strategies using either hs-cTnT or hs-cTnI in both cohorts (all statistical comparisons nonsignificant). The percentage of patients triaged toward rule-out was significantly lower with the 2h-ADP (36%-43%) vs the 2-h algorithm (55%-68%) with both assays and in both cohorts (P < 0.001). The sensitivity of the 2h-ADP was higher for 30-day major adverse cardiovascular events. CONCLUSIONS: Both algorithms provided very high and comparable safety as quantified by the NPV and sensitivity for AMI and major adverse cardiac events (MACE) at 30 days in patients triaged toward rule-out, although sensitivity for MACE at 30 days was lower with both algorithms in cohort 2. Although the 2-h algorithm was more efficacious, not all patients ruled out for AMI by this algorithm were appropriate candidates for early discharge. The 2h-ADP seems superior in the selection of patients for early discharge from the ED. CLINICAL TRIAL REGISTRATION: APACE: http://clinicaltrials.gov/show/NCT00470587ADAPT: Australia-New Zealand Clinical Trials Registry ACTRN12611001069943.

Implementing change: evaluating the Accelerated Chest pain Risk Evaluation (ACRE) project.

OBJECTIVE: To evaluate hospital length of stay (LOS) and admission rates before and after implementation of an evidence-based, accelerated diagnostic protocol (ADP) for patients presenting to emergency departments (EDs) with chest pain. DESIGN: Quasi-experimental design, with interrupted time series analysis for the period October 2013 - November 2015. Setting, participants: Adults presenting with chest pain to EDs of 16 public hospitals in Queensland. INTERVENTION: Implementation of the ADP by structured clinical re-design. MAIN OUTCOME MEASURES: Primary outcome: hospital LOS. SECONDARY OUTCOMES: ED LOS, hospital admission rate, proportion of patients identified as being at low risk of an acute coronary syndrome (ACS). RESULTS: Outcomes were recorded for 30 769 patients presenting before and 23 699 presenting after implementation of the ADP. Following implementation, 21.3% of patients were identified by the ADP as being at low risk for an ACS. Following implementation of the ADP, mean hospital LOS fell from 57.7 to 47.3 hours (rate ratio [RR], 0.82; 95% CI, 0.74-0.91) and mean ED LOS for all patients presenting with chest pain fell from 292 to 256 minutes (RR, 0.80; 95% CI, 0.72-0.89). The hospital admission rate fell from 68.3% (95% CI, 59.3-78.5%) to 54.9% (95% CI, 44.7-67.6%; P < 0.01). The estimated release in financial capacity amounted to $2.3 million as the result of reduced ED LOS and $11.2 million through fewer hospital admissions. CONCLUSIONS: Implementing an evidence-based ADP for assessing patients with chest pain was feasible across a range of hospital types, and achieved a substantial release of health service capacity through reductions in hospital admissions and ED LOS.

Improved Assessment of Chest pain Trial (IMPACT): assessing patients with possible acute coronary syndromes.

OBJECTIVE: To examine the safety and efficacy of the Improved Assessment of Chest pain Trial (IMPACT) protocol, a strategy for accelerated assessment of patients presenting to emergency departments (EDs) with chest pain. DESIGN, SETTING AND PARTICIPANTS: IMPACT was an intervention trial at a single tertiary referral hospital (Royal Brisbane and Women's Hospital) during February 2011 - March 2014. 1366 prospectively recruited patients presenting to the ED with symptoms of suspected acute coronary syndrome (ACS) were stratified into groups at low, intermediate or high risk of an ACS. INTERVENTION: High risk patients were treated according to NHFA/CSANZ guidelines. Low and intermediate risk patients underwent troponin testing (sensitive assay) 0 and 2 hours after presentation. Intermediate risk patients underwent objective testing after the second troponin test; low risk patients were discharged without further objective testing. MAIN OUTCOME MEASURES: The primary outcome was an ACS within 30 days of presentation. Secondary outcomes were ED and hospital lengths of stay (LOS). RESULTS: The IMPACT protocol stratified 244 (17.9%) patients to low risk, 789 (57.7%) to intermediate risk, and 333 (24.4%) to high risk categories. The overall 30-day ACS rate was 6.6%, but there were no ACS events in the low risk group, and 14 (1.8%) in the intermediate risk group. The median hospital LOS was 5.1 hours (IQR, 4.2-5.6 h) for low risk and 7.7 hours (IQR, 6.1-21 h) for intermediate risk patients. CONCLUSIONS: The IMPACT protocol safely and efficiently allowed a large proportion of patients presenting to EDs with chest pain to undergo accelerated assessment for risk of an ACS. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12611000206921.

Validating the Manchester Acute Coronary Syndromes (MACS) and Troponin-only Manchester Acute Coronary Syndromes (T-MACS) rules for the prediction of acute myocardial infarction in patients presenting to the emergency department with chest pain.

BACKGROUND: The Manchester Acute Coronary Syndromes (MACS) rule and the Troponin-only MACS (T-MACS) rule risk stratify patients with suspected acute coronary syndrome (ACS). This observational study sought to validate and compare the MACS and T-MACS rules for assessment of acute myocardial infarction (AMI). METHODS: Prospectively collected data from twoEDs in Australia and New Zealand were analysed. Patients were assigned a probability of ACS based on the MACS and T-MACS rules, incorporating high-sensitivity troponin T, heart-type fatty acid-binding protein, ECG results and clinical symptoms. Patients were then deemed very low risk, low risk, intermediate or high risk if their MACS probability was less than 2%, between 2% and 5%, between 5% and 95% and greater than 95%, respectively. The primary endpoint was 30-day diagnosis of AMI. The secondary endpoint was 30-day major adverse cardiac event (MACE) including AMI, revascularisation or coronary stenosis (>70%). Sensitivity, specificity and predictive values were calculated to assess the accuracy of the MACS and T-MACS rules. RESULTS: Of the 1244 patients, 114 (9.2%) were diagnosed with AMI and 163 (13.1%) with MACE. The MACS and T-MACS rules categorised 133 (10.7%) and 246 (19.8%) patients, respectively, as very low risk and potentially suitable for early discharge from the ED. There was one false negative case for both rules making sensitivity 99.1% (95.2%-100%). CONCLUSIONS: MACS and T-MACS accurately risk stratify very low risk patients. The T-MACS rule would allow for more patients to be discharged early. The potential for missed MACE events means that further outpatient testing for coronary artery disease may be required for patients identified as very low risk.