Factors influencing variation in investigations after a negative CT brain scan in suspected subarachnoid haemorrhage: a qualitative study.

INTRODUCTION: Variation in the approach to the patient with a possible subarachnoid haemorrhage (SAH) has been previously documented. The purpose of this study was to identify factors that influence emergency physicians' decisions about diagnostic testing after a normal CT brain scan for ED patients with a headache suspicious of a SAH. METHODS: We conducted an interview-based qualitative study informed by social constructionist theory. Fifteen emergency physicians from six EDs across Queensland, Australia, underwent individual face-to-face or telephone interviews. Content analysis was performed whereby transcripts were examined and coded independently by two co-investigators, who then jointly agreed on the influencing factors. RESULTS: Six categories of influencing factors were identified. Patient interaction was at the forefront of the identified factors. This shared decision-making process incorporated 'what the patient wants' but may be biased by how the clinician communicates the benefits and harms of the diagnostic options to the patient. Patient risk profile, practice evidence and guidelines were also important. Other influencing factors included experiential factors of the clinician, consultation with colleagues and external influences where practice location and work processes impose constraints on test ordering external to the preferences of the clinician or patient. The six categories were organised within a conceptual framework comprising four components: the context, the evidence, the experience and the decision. CONCLUSIONS: When clinicians are faced with a diagnostic challenge, such as the workup of a patient with suspected SAH, there are a number of influencing factors that can result in a variation in approach. These need to be considered in approaches to improve the appropriateness and consistency of medical care.

Applying the Ottawa subarachnoid haemorrhage rule on a cohort of emergency department patients with headache.

OBJECTIVE: The Ottawa subarachnoid haemorrhage (SAH) rule suggests that alert patients older than 15 years with a severe nontraumatic headache reaching maximum intensity within 1 h and absence of high-risk variables effectively have a SAH ruled out. We aimed to determine the proportion of emergency department (ED) patients with any headache fulfilling the entry criteria for the Ottawa SAH rule. PATIENTS AND METHODS: The Ottawa SAH rule was applied retrospectively in a substudy of a prospective snapshot of 34 EDs in Queensland, Australia, carried out over 4 weeks in September 2014. Patient aged 18 years and older with a nontraumatic headache of any potential cause were included. Clinical data and results of investigations were collected. RESULTS: Data were available for 644 (76%) patients. A total of 149 (23.1%, 95% confidence interval: 20.0-26.5%) fulfilled and 495 (76.9%, 95% confidence interval: 73.5-80.0%) did not fulfil the entry criteria. In patients who fulfilled the entry criteria, 30 (<5% overall) did not have any high-risk variables for SAH. In patients who fulfilled the entry criteria and had at least 1 high-risk feature, almost half (46%) received a computed tomographic brain. No SAH were missed. CONCLUSION: In this descriptive observational study, the majority of ED patients presenting with a headache did not fulfil the entry criteria for the Ottawa SAH rule. Less than 5% of the patients in this cohort could have SAH excluded on the basis of the rule. More definitive studies are needed to determine an accepted benchmark for the proportion of patients receiving further work-up (computed tomographic brain) after fulfilling the entry criteria for the Ottawa SAH rule.

Characteristics, treatment and outcomes for all emergency department patients fulfilling criteria for septic shock: a prospective observational study.

OBJECTIVE: Most published data on emergency department (ED) patients with septic shock have been generated from studies examining the effect of early protocolised resuscitation in selected cohorts. Consequently, these data do not generally represent patients falling outside trial inclusion criteria or judged unsuitable for aggressive treatment. Our aim was to determine the characteristics, treatment and outcomes for all ED patients fulfilling the criteria for septic shock. METHODS: Septic shock patients were identified from a prospective database of consecutive ED patients admitted with infection. Descriptive data were compared with those from previous studies and associations between ED processes of care and mortality were determined. RESULTS: A total of 399 septic shock patients were identified, with a 30-day mortality of 19.5%. The median ED length of stay was 9.2 h. Rates of vasopressor use (22.6%) and ICU admission (37.3%) were low. Subgroups fulfilling the lactate criteria alone, hypotension criteria alone and both criteria represented distinct shock phenotypes with increasing severity of illness and mortality. Mortality for patients with limitations to treatment determined in the ED was 65.6% and 6.1% for those without limitations. Greater volumes of intravenous fluid and early vasopressor therapy for appropriate patients were associated with survival. CONCLUSION: Median length of stay over 9 hours may have enhanced identification of patients with limitations to treatment and fluid responders, reducing invasive therapies and ICU admissions. Distinct shock phenotypes were apparent, with implications for revision of septic shock definitions and future trial design. Liberal fluids and early vasopressor use in appropriate patients were associated with survival.

Analysis of h-index and other bibliometric markers of productivity and repercussion of a selected sample of worldwide emergency medicine researchers.

OBJECTIVE: To explore bibliometric markers in a worldwide sample of emergency physician investigators to define global, continental and individual patterns over time. METHODS: We evaluated the number of papers published, citations received, cumulative impact factor and h-index of editorial board members of six international emergency medicine journals. We calculated the individual values for every year of each author's career to evaluate their dynamic evolution. We analysed the results by researcher world area and growth rate. RESULTS: We included 107 researchers (76 American, 21 European and 10 Australasian; 46 slow-rate -group C-, 43 medium-rate -group B- and 18 fast-rate growth -group A-). The median experience was 18 (IQR: 12) years, without subgroups differences. Dynamic analysis over time showed good fit with quadratic function in all individual researchers and for all bibliometric markers (R2: 0.505-0.997), with the h-index achieving the best R2. The combined analysis of the h-index of the 107 investigators also fit the quadratic model (R2=0.49). Analysis by predefined continental and growth-rate subgroups allowed defining specific patterns (R2 between 0.46-0.54 and 0.80-0.86, respectively): by continents, American researchers' h-index increased 0.632 points per year, European 0.417 and Australasian 0.341; by growth rate, researchers from group A, B and C increased 1.239, 0.683 and 0.320, respectively. CONCLUSIONS: Dynamic analysis of every individual author indicator over time has a very good fit with a quadratic model, with the h-index achieving the best R2. It is also possible to construct models based on continent and rate of growth that could help to predict future expected outcomes of researchers in a particular subgroup and to classify new emerging researchers by growth rate.

Systemic Inflammatory Response Syndrome, Quick Sequential Organ Function Assessment, and Organ Dysfunction: Insights From a Prospective Database of ED Patients With Infection.

BACKGROUND: A proposed revision of sepsis definitions has abandoned the systemic inflammatory response syndrome (SIRS), defined organ dysfunction as an increase in total Sequential Organ Function Assessment (SOFA) score of ≥ 2, and conceived "qSOFA" (quick SOFA) as a bedside indicator of organ dysfunction. We aimed to (1) determine the prognostic impact of SIRS, (2) compare the diagnostic accuracy of SIRS and qSOFA for organ dysfunction, and (3) compare standard (Sepsis-2) and revised (Sepsis-3) definitions for organ dysfunction in ED patients with infection. METHODS: Consecutive ED patients admitted with presumed infection were prospectively enrolled over 3 years. Sufficient observational data were collected to calculate SIRS, qSOFA, SOFA, comorbidity, and mortality. RESULTS: We enrolled 8,871 patients, with SIRS present in 4,176 (47.1%). SIRS was associated with increased risk of organ dysfunction (relative risk [RR] 3.5) and mortality in patients without organ dysfunction (OR 3.2). SIRS and qSOFA showed similar discrimination for organ dysfunction (area under the receiver operating characteristic curve, 0.72 vs 0.73). qSOFA was specific but poorly sensitive for organ dysfunction (96.1% and 29.7%, respectively). Mortality for patients with organ dysfunction was similar for Sepsis-2 and Sepsis-3 (12.5% and 11.4%, respectively), although 29% of patients with Sepsis-3 organ dysfunction did not meet Sepsis-2 criteria. Increasing numbers of Sepsis-2 organ system dysfunctions were associated with greater mortality. CONCLUSIONS: SIRS was associated with organ dysfunction and mortality, and abandoning the concept appears premature. A qSOFA score ≥ 2 showed high specificity, but poor sensitivity may limit utility as a bedside screening method. Although mortality for organ dysfunction was comparable between Sepsis-2 and Sepsis-3, more prognostic and clinical information is conveyed using Sepsis-2 regarding number and type of organ dysfunctions. The SOFA score may require recalibration.

Acute Headache Presentations to the Emergency Department: A Statewide Cross-sectional Study.

OBJECTIVES: The objective of this study was to describe demographic and clinical characteristics including features that were consistent with subarachnoid hemorrhage (SAH), use of diagnostic tests, emergency department (ED) discharge diagnoses, and disposition of adult patients presenting with an acute headache to EDs statewide across Queensland, Australia. In addition, potential variations in the presentation and diagnostic workup between principal-referral and city-regional hospitals were examined. METHODS: A prospective cross-sectional study was conducted over 4 weeks in September 2014. All patients ≥ 18 years presenting to one of 29 public and five private hospital EDs across the state with an acute headache were included. The headache had to be the principal presenting complaint and nontraumatic. The 34 study sites attend to about 90% of all ED presentations statewide. The treating doctor collected clinical information at the time of the ED visit including the characteristics of the headache and investigations performed. A study coordinator retrieved results of investigations, ED discharge diagnoses, and disposition from state databases. Variations in presentation, investigations, and diagnosis between city-regional and principal-referral hospitals were examined. RESULTS: There were 847 headache presentations. Median (range) age was 39 (18-92) years, 62% were female, and 31% arrived by ambulance. Headache peaked instantly in 18% and ≤ 1 hour in 44%. It was "worst ever" in 37%, 10/10 in severity in 23%, and associated with physical activity in 7.4%. Glasgow Coma Scale score was < 15 in 4.1%. Neck stiffness was noted on examination in 4.8%. Neurologic deficit persisting in the ED was found in 6.5%. A computed tomography (CT) head scan was performed in 38% (318/841, 95% CI = 35% to 41%) and an lumbar puncture in 4.7% (39/832, 95% CI = 3.4% to 6.3%). There were 18 SAH, six intraparenchymal hemorrhages, one subdural hematoma, one newly diagnosed brain metastasis, and two bacterial meningitis. Migraine was diagnosed in 23% and "primary headache not further specified" in 45%. CT head scans were more likely to be performed in principal-referral hospitals (41%) compared to city-regional hospitals (33%). The headache in patients presenting to the latter was less likely to be instantly peaking or associated with activity, but was no less severe in intensity and was more frequently accompanied by nausea and vomiting. Their diagnosis was more likely to be a benign primary headache. Variations in CT scanning could thus be due to differences in the case mix. The median (interquartile range) ED length of stay was 3.1 (2.2 to 4.5) hours. Patients was discharged from the ED or admitted to the ED short-stay unit prior to discharge in 57 and 23% of cases, respectively. CONCLUSIONS: The majority of patients had a benign diagnosis, with intracranial hemorrhage and bacterial meningitis accounting for only 3% of the diagnoses. There are variations in the proportion of patients receiving CT head scans between city-regional and principal-referral hospitals. As 38% of headache presentations overall underwent CT scanning, there is scope to rationalize diagnostic testing to rule out life-threatening conditions.

Double-dorsal versus single-volar digital subcutaneous anaesthetic injection for finger injuries in the emergency department: A randomised controlled trial.

OBJECTIVE: The objective of this present study is to compare pain associated with the double-dorsal versus a single-volar subcutaneous injection in the provision of digital anaesthesia for finger injuries presenting to the ED. METHODS: A randomised controlled trial from November 2012 to January 2014 at a single adult tertiary-referral hospital. ED patients with finger injuries requiring digital anaesthesia was randomised to either the double-dorsal or a single-volar subcutaneous injection technique. The primary outcome was patient reported injection pain measured on a 100 mm visual analogue scale with the assessor blinded to the injection technique. The secondary outcome was success of anaesthesia defined as ability to perform the assessment and treatment without further anaesthetic supplementation after 5 min. RESULTS: Eighty-six patients were enrolled. Median (IQR) age was 34 (24-47) years and 79% were men. The majority (66.3%) had distal phalanx injuries. Forty patients were randomised to the double-dorsal and 46 to a single-volar subcutaneous injection technique. The mean (standard deviation) pain score of the double-dorsal injection was 39.1 (24.2) and a single-volar injection was 37.3 (24.5) with a difference of 1.8 (95% CI -8.8 to 12.3). Digital anaesthesia was successful in 64.9% of the double-dorsal and 71.7% of the single-volar subcutaneous injections, a difference of 6.8% (95% CI -12.7 to 26.3). CONCLUSION: In ED patients with finger injuries requiring digital anaesthesia, both the double-dorsal or single-volar subcutaneous injection techniques have similar pain of injection and success rates of anaesthesia. Single-volar injection appears suitable alternative to the commonly performed double-dorsal injection in the ED.

Severity Scores in Emergency Department Patients With Presumed Infection: A Prospective Validation Study.

OBJECTIVES: The objectives of this study were to 1) validate a number of severity of illness scores in a large cohort of emergency department patients admitted with presumed infection and 2) compare the performance of scores in patient subgroups with increasing mortality: infection without systemic inflammatory response syndrome, sepsis, severe sepsis, and septic shock. DESIGN: Prospective, observational study. SETTING: Adult emergency department in a metropolitan tertiary, university-affiliated hospital. PATIENTS: Emergency department patients admitted with presumed infection. INTERVENTIONS: None. METHODS: Consecutive emergency department patients admitted with presumed infection were identified over 160 weeks in two periods between 2007 and 2011. Clinical and laboratory data sufficient to calculate Mortality in Emergency Department Sepsis score, Acute Physiology and Chronic Health Evaluation II, Simplified Acute Physiology Score II, Sequential Organ Failure Assessment, and the Severe Sepsis Score were entered into a database. Model discrimination was quantified using area under the receiver operating curve. Calibration was assessed using visual plots, Hosmer-Lemeshow statistics, and linear regressions of observed and predicted values. MEASUREMENTS AND MAIN RESULTS: A total of 8,871 patients were enrolled with 30-day mortality of 3.7%. Area under the receiver operating curve values for the entire cohort were: Mortality in Emergency Department Sepsis score of 0.92, Simplified Acute Physiology Score II and Acute Physiology and Chronic Health Evaluation II scores of 0.90, Sequential Organ Failure Assessment score of 0.86, and Severe Sepsis Score of 0.82. Discrimination decreased in subgroups with greater mortality for each score. All scores overestimated mortality, but closest concordance between predicted and observed mortality was seen with Mortality in Emergency Department Sepsis score. CONCLUSIONS: The decrease in area under the receiver operating curve seen in subgroups with increasing mortality may explain some variation in results seen in previous validation studies. Scores developed in intensive care settings overestimated mortality in the emergency department. Our results underscore the importance of employing predictive models developed in similar patient populations. The Mortality in Emergency Department Sepsis score outperformed more complex predictive models and would be the most appropriate scoring system for use in similar emergency department populations with a wide spectrum of mortality risk.

Factors associated with triage assignment of emergency department patients ultimately diagnosed with acute myocardial infarction.

BACKGROUND: The objective of this study was to explore factors associated with the triage category assigned by the triage nurse for patients ultimately diagnosed with acute myocardial infarction. METHODS: This was a retrospective analysis of 12 months of data, on adult emergency department patients ultimately diagnosed with acute myocardial infarction. Data were obtained from hospital databases and included patient demographics, patient clinical characteristics and nurses' experience. RESULTS: Of the 153 patients, 20% (95% CI: 14-27%) were given a lower urgency triage category than recommended by international guidelines. Compared to patients who were triaged Australasian Triage Category 1 or 2, patients with an Australasian Triage Category 3-5 were older (mean age 76 versus 68 years), more likely to be female (63% versus 32%), more likely to present without chest pain (93% versus 35%) and less likely to have a cardiac history (3.3% versus 17.9%). A slightly higher proportion of patients Australasian Triage Category 3-5 were triaged by an experienced nurse (50%) compared to patients categorised Australasian Triage Category 1-2 (35.2%) but this finding did not reach statistical significance. CONCLUSIONS: One in five presentations was given a lower urgency triage category than recommended by international guidelines, potentially leading to delays in medical treatment. The absence of chest pain was the defining characteristic in this group of patients, along with other factors identified by previous research such as being of female sex and elderly.

Utility of Routine Exercise Stress Testing among Intermediate Risk Chest Pain Patients Attending an Emergency Department.

BACKGROUND: To assess the utility of routine exercise stress testing (EST) in patients at intermediate risk of acute coronary syndrome (ACS) according to the Heart Foundation of Australia/Cardiac Society of Australia and New Zealand (HFA/CSANZ) guidelines. METHOD: Prospective observational study of patients presenting to the Emergency Department (ED) with chest pain suggestive of ACS between November 2008 and July 2014. Participants included 1205 patients who presented to the ED with chest pain suggestive of ACS and who met the HFA/CSANZ intermediate risk criteria. The outcome was diagnosis of ACS occurring on presentation or within 30 days of presentation to the ED. ACS included acute myocardial infarction and unstable angina pectoris. RESULTS: Twenty (1.66%) of the intermediate risk patients were diagnosed with ACS. Of the 777 patients who underwent EST, eight had ACS. EST identified all ACS cases except for one patient with a negative test, who was ultimately diagnosed with ACS following angiography. 164 patients deemed inappropriate to undergo EST underwent an alternative form of objective testing, of which 12 were positive for ACS. 264 patients underwent no objective testing. CONCLUSION: EST stratifies intermediate risk patients to a near zero short-term risk of ACS. However, the overall yield of EST within this group of patients is extremely low. Intermediate risk patients with normal zero and six hour biomarkers have a very low probability of ACS, and over half of these patients ultimately diagnosed with ACS in this group were deemed unsuitable for EST anyway. Future research should focus on the identification of patients who do not require EST and the inclusion of routine EST within the HFA/CSANZ guidelines should be reconsidered.

Cost and outcomes of assessing patients with chest pain in an Australian emergency department.

OBJECTIVES: We sought to characterise the demographics, length of admission, final diagnoses, long-term outcome and costs associated with the population who presented to an Australian emergency department (ED) with symptoms of possible acute coronary syndrome (ACS). DESIGN, SETTING AND PARTICIPANTS: Prospectively collected data on ED patients presenting with suspected ACS between November 2008 and February 2011 was used, including data on presentation and at 30 days after presentation. Information on patient disposition, length of stay and costs incurred was extracted from hospital administration records. MAIN OUTCOME MEASURES: Primary outcomes were mean and median cost and length of hospital stay. Secondary outcomes were diagnosis of ACS, other cardiovascular conditions or non-cardiovascular conditions within 30 days of presentation. RESULTS: An ACS was diagnosed in 103 (11.1%) of the 926 patients recruited. 193 patients (20.8%) were diagnosed with other cardiovascular-related conditions and 622 patients (67.2%) had non-cardiac-related chest pain. ACS events occurred in 0 and 11 (1.9%) of the low-risk and intermediate-risk groups, respectively. Ninety-two (28.0%) of the 329 high-risk patients had an ACS event. Patients with a proven ACS, high-grade atrioventricular block, pulmonary embolism and other respiratory conditions had the longest length of stay. The mean cost was highest in the ACS group ($13 509; 95% CI, $11 794-$15 223) followed by other cardiovascular conditions ($7283; 95% CI, $6152-$8415) and non-cardiovascular conditions ($3331; 95% CI, $2976-$3685). CONCLUSIONS: Most ED patients with symptoms of possible ACS do not have a cardiac cause for their presentation. The current guideline-based process of assessment is lengthy, costly and consumes significant resources. Investigation of strategies to shorten this process or reduce the need for objective cardiac testing in patients at intermediate risk according to the National Heart Foundation and Cardiac Society of Australia and New Zealand guideline is required.

Relationship between category size and journals' impact factor: implications for emergency medicine journals and researchers.

OBJECTIVE: We assessed the relationship between the size of the 39 Journal Citation Reports (JCR) medical categories and impact factor (IF) of journals in these categories, and the implications that it might have for emergency medicine (EM) journals. MATERIALS AND METHODS: Using the 2010 JCR database, we calculated the mean IF, 5-year IF (5y-IF), Eigenfactor (EF), and Article Influence (AI) scores including all journals for each category. We also calculated a 'weighted IF' for all journals by dividing each journal IF by the mean IF of its category. We ranked EM journals according to IF and 'weighted IF' into all the journals included in the 39 categories. We assessed the relationship between category size and bibliometric scores by linear regression. RESULTS: Category size varied from 252 journals (Pharmacology and Pharmacy) to 14 (Primary Healthcare), EM category occupying the 36th position (23 journals). The mean IF of EM category ranked in 34th position, 5-yIF in 32nd, EF in 34th, and AI in 34th position. Category size had a direct and significant association with mean IF, 5y-IF, and AI but not with mean EF. When the EM journals were ranked among all the journals according to their IF, only two (9%) were placed into the first quartile and raised up to eight (35%) when 'weighted IF' was considered. CONCLUSION: There is a negative relationship between JCR size category and IF achieved by the journals. This places EM journals at a clear disadvantage because they represent one of the smallest clinical medical research disciplines.

Triaging older major trauma patients in the emergency department: an observational study.

BACKGROUND: The objective of this study was to compare the triage category assigned to older trauma patients with younger trauma patients upon arrival to the emergency department. The focus was to examine whether older major trauma patients were less likely to be assigned an emergency triage category on arrival to the emergency department after controlling for relevant demographics, injury characteristics and injury severity. METHODS: This was an observational study using data from the Queensland Trauma Registry. All trauma patients aged 15 years and older who presented to contributing hospitals between 1 January 2005 and 31 December 2009 with an Injury Severity Score (ISS)>15 were included. Logistic regression analysis examined the odds of assignment to emergency (Australasian Triage Scale (ATS) 1 or 2) versus urgent (ATS 3-5) treatment for patients across various age categories after adjustment for relevant demographics, injury characteristics and injury severity. RESULTS: The study used data on 6923 patients with a median (IQR) age of 43 (26-62) years and a mortality of 11.4% (95% CI 10.7% to 12.2%). Compared with individuals aged 15-34, the adjusted odds of being assigned an ATS category 1 or 2 were 30% lower (OR=0.68, 95% CI 0.57 to 0.81) for individuals aged 55-75 years and were 50% lower (OR=0.46, 95% CI 0.37 to 0.56) for individuals aged 75 years or older. CONCLUSIONS: Among patients with an ISS>15, older major trauma patients were less likely to be assigned an emergency triage category compared with younger patients. This suggests that the elderly may be undertriaged and provides a potential area of study for reducing mortality and morbidity in older trauma patients.

Limited utility of exercise stress testing in the evaluation of suspected acute coronary syndrome in patients aged less than 40 years with intermediate risk features.

OBJECTIVE: National guidelines for management of intermediate risk patients with suspected acute coronary syndrome, in whom AMI has been excluded, advocate provocative testing to final risk stratify these patients into low risk (negative testing) or high risk (positive testing suggestive of unstable angina). Adults less than 40 years have a low pretest probability of acute coronary syndrome. The utility of exercise stress testing in young adults with chest pain suspected of acute coronary syndrome who have National Heart Foundation intermediate risk features was evaluated. METHODS: A retrospective analysis of exercise stress testing performed on patients less than 40 years was evaluated. Patients were enrolled on a chest pain pathway and had negative serial ECGs and cardiac biomarkers before exercise stress testing to rule-out acute coronary syndrome. Chart review was completed on patients with positive stress tests. RESULTS: The 3987 patients with suspected intermediate risk acute coronary syndrome underwent exercise stress testing. One thousand and twenty-seven (25.8%) were aged less than 40 years (age 33.3 ± 4.8 years). Four of these 1027 patients had a positive exercise stress test (0.4% incidence of positive exercise stress testing). Of those, three patients had subsequent non-invasive functional testing that yielded a negative result. One patient declined further investigations. Assuming this was a true positive exercise stress test, the incidence of true positive exercise stress testing would have been 0.097% (95% confidence interval: 0.079-0.115%) (one of 1027 patients). CONCLUSIONS: Routine exercise stress testing has limited value in the risk stratification of adults less than 40 years with suspected intermediate risk of acute coronary syndrome.

Validation of an accelerated high-sensitivity troponin T assay protocol in an Australian cohort with chest pain.

OBJECTIVES: To validate an accelerated biomarker strategy using a high-sensitivity cardiac troponin T (hs-cTnT) assay for diagnosing acute myocardial infarction (AMI) in patients presenting to the emergency department with chest pain; and to validate this strategy in combination with the National Heart Foundation of Australia/Cardiac Society of Australia and New Zealand risk stratification model. DESIGN, SETTING AND PATIENTS: Single-centre, prospective, observational cohort study of 764 adults presenting to a tertiary hospital with symptoms of possible acute coronary syndrome between November 2008 and February 2011. MAIN OUTCOME MEASURES: AMI or cardiac death within 24 hours of presentation (primary), and major adverse cardiac events within 30 days (secondary). RESULTS: An elevated hs-cTnT assay result above the 99th percentile at either the 0 h or 2 h time points had sensitivity of 96.4% (95% CI, 87.9%-99.0%), specificity of 82.6% (95% CI, 79.7%-85.2%), negative predictive value of 99.7% (95% CI, 98.8%-99.9%) and positive predictive value of 30.5% (95% CI, 24.2%-37.6%) for diagnosing AMI. Compared with a traditional 6 h cardiac troponin testing strategy, the accelerated strategy led to reclassification of risk in only two patients with adverse cardiac outcomes, with no net effect on appropriate management. CONCLUSIONS: In patients presenting with chest pain, an accelerated biomarker strategy using the hs-cTnT assay performed well in the initial diagnosis of AMI. The accelerated strategy was also effective when incorporated into a comprehensive strategy of risk stratification that included clinical and demographic factors. The time saved by this approach could have a major impact on health service delivery. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12610000053022.

Comparison of high sensitivity troponin T and I assays in the diagnosis of non-ST elevation acute myocardial infarction in emergency patients with chest pain.

OBJECTIVES: Concentrations of troponin measured with high sensitivity troponin assays are raised in a number of emergency department (ED) patients; however many are not diagnosed with acute myocardial infarction (AMI). Clinical comparisons between the early use (2h after presentation) of high sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI) assays for the diagnosis of AMI have not been reported. DESIGN AND METHODS: Early (0 h and 2 h) hs-cTnT and hs-cTnI assay results in 1571 ED patients with potential acute coronary syndrome (ACS) without ST elevation on electrocardiograph (ECG) were evaluated. The primary outcome was diagnosis of index AMI adjudicated by cardiologists using the local cTnI assay results taken ≥6 h after presentation, ECGs and clinical information. Stored samples were later analysed with hs-cTnT and hs-cTnI assays. RESULTS: The ROC analysis for AMI (204 patients; 13.0%) for hs-cTnT and hs-cTnI after 2h was 0.95 (95% CI: 0.94-0.97) and 0.98 (95% CI: 0.97-0.99) respectively. The sensitivity, specificity, PLR, and NLR of hs-cTnT and hs-cTnI for AMI after 2h were 94.1% (95% CI: 90.0-96.6) and 95.6% (95% CI: 91.8-97.7), 79.0% (95% CI: 76.8-81.1) and 92.5% (95% CI: 90.9-93.7), 4.48 (95% CI: 4.02-5.00) and 12.86 (95% CI: 10.51-15.31), and 0.07 (95% CI: 0.04-0.13) and 0.05 (95% CI:0.03-0.09) respectively. CONCLUSIONS: Exclusion of AMI 2h after presentation in emergency patients with possible ACS can be achieved using hs-cTnT or hs-cTnI assays. Significant differences in specificity of these assays are relevant and if using the hs-cTnT assay, further clinical assessment in a larger proportion of patients would be required.

The new Vancouver Chest Pain Rule using troponin as the only biomarker: an external validation study.

OBJECTIVES: To externally evaluate the accuracy of the new Vancouver Chest Pain Rule and to assess the diagnostic accuracy using either sensitive or highly sensitive troponin assays. METHODS: Prospectively collected data from 2 emergency departments (EDs) in Australia and New Zealand were analysed. Based on the new Vancouver Chest Pain Rule, low-risk patients were identified using electrocardiogram results, cardiac history, nitrate use, age, pain characteristics and troponin results at 2 hours after presentation. The primary outcome was 30-day diagnosis of acute coronary syndrome (ACS), including acute myocardial infarction, and unstable angina. Sensitivity, specificity, positive predictive values and negative predictive values were calculated to assess the accuracy of the new Vancouver Chest Pain Rule using either sensitive or highly sensitive troponin assay results. RESULTS: Of the 1635 patients, 20.4% had an ACS diagnosis at 30 days. Using the highly sensitive troponin assay, 212 (13.0%) patients were eligible for early discharge with 3 patients (1.4%) diagnosed with ACS. Sensitivity was 99.1% (95% CI 97.4-99.7), specificity was 16.1 (95% CI 14.2-18.2), positive predictive values was 23.3 (95% CI 21.1-25.5) and negative predictive values was 98.6 (95% CI 95.9-99.5). The diagnostic accuracy of the rule was similar using the sensitive troponin assay. CONCLUSIONS: The new Vancouver Chest Pain Rule should be used for the identification of low risk patients presenting to EDs with symptoms of possible ACS, and will reduce the proportion of patients requiring lengthy assessment; however we recommend further outpatient investigation for coronary artery disease in patients identified as low risk.

Performance of risk stratification for acute coronary syndrome with two-hour sensitive troponin assay results.

BACKGROUND: Risk stratification processes for patients with possible acute coronary syndrome (ACS) recommend the use of serial sensitive troponin testing over at least 6h. Troponin assays vary in their analytical performance. Utility in accurate risk stratification at 2h post-presentation is unknown. METHODS: A diagnostic accuracy study of patients presenting to the emergency department (ED) with symptoms of ACS was performed. Troponin was measured at 0, 2 and 6h post-presentation. Acute myocardial infarction (AMI) was adjudicated by cardiologists and incorporated the 0 and 6h troponin values measured by a sensitive troponin assay. Results were described using standard measures of test accuracy. RESULTS: Of the 685 patients, 51 (7.4%) had 30-day AMI or cardiac death, and 76 (11.1%) had secondary outcomes (all cause death, ACS and revascularisation procedures). There was no significant difference in the diagnostic accuracy of early versus late biomarker strategies when used with the current risk stratification processes. Incorporation of a significant delta did not improve the stratification at 2h post-presentation. CONCLUSIONS: Accelerated risk stratification of patients with ACS symptoms may occur at 2h post-presentation using troponin results measured by a sensitive assay. Incorporation of such a strategy could support improvements in patient flow within EDs.