Christopher J. Hammett

2-Hour accelerated diagnostic protocol to assess patients with chest pain symptoms using contemporary troponins as the only biomarker: the ADAPT trial.

OBJECTIVES The purpose of this study was to determine whether a new accelerated diagnostic protocol (ADP) for possible cardiac chest pain could identify low-risk patients suitable for early discharge (with follow-up shortly after discharge). BACKGROUND Patients presenting with possible acute coronary syndrome (ACS), who have a low short-term risk of adverse cardiac events may be suitable for early discharge and shorter hospital stays. METHODS This prospective observational study tested an ADP that included pre-test probability scoring by the Thrombolysis In Myocardial Infarction (TIMI) score, electrocardiography, and 0 + 2 h values of laboratory troponin I as the sole biomarker. Patients presenting with chest pain due to suspected ACS were included. The primary endpoint was major adverse cardiac event (MACE) within 30 days. RESULTS Of 1,975 patients, 302 (15.3%) had a MACE. The ADP classified 392 patients (20%) as low risk. One (0.25%) of these patients had a MACE, giving the ADP a sensitivity of 99.7% (95% confidence interval [CI]: 98.1% to 99.9%), negative predictive value of 99.7% (95% CI: 98.6% to 100.0%), specificity of 23.4% (95% CI: 21.4% to 25.4%), and positive predictive value of 19.0% (95% CI: 17.2% to 21.0%). Many ADP negative patients had further investigations (74.1%), and therapeutic (18.3%) or procedural (2.0%) interventions during the initial hospital attendance and/or 30-day follow-up. CONCLUSIONS Using the ADP, a large group of patients was successfully identified as at low short-term risk of a MACE and therefore suitable for rapid discharge from the emergency department with early follow-up. This approach could decrease the observation period required for some patients with chest pain. (An observational study of the diagnostic utility of an accelerated diagnostic protocol using contemporary central laboratory cardiac troponin in the assessment of patients presenting to two Australasian hospitals with chest pain of possible cardiac origin; ACTRN12611001069943).

Acute coronary syndrome care across Australia and New Zealand: the SNAPSHOT ACS study.

Objectives: To characterise management of suspected acute coronary syndrome (ACS) in Australia and New Zealand, and to assess the application of recommended therapies according to published guidelines.

Two-Hour Algorithm for Triage toward Rule-Out and Rule-In of Acute Myocardial Infarction by Use of High-Sensitivity Cardiac Troponin I

BACKGROUND The early triage of patients toward rule-out and rule-in of acute myocardial infarction (AMI) is challenging. Therefore, we aimed to develop a 2-h algorithm that uses high-sensitivity cardiac troponin I (hs-cTnI). METHODS We prospectively enrolled 1435 (derivation cohort) and 1194 (external validation cohort) patients presenting with suspected AMI to the emergency department. The final diagnosis was adjudicated by 2 independent cardiologists. hs-cTnI was measured at presentation and after 2 h in a blinded fashion. We derived and validated a diagnostic algorithm incorporating hs-cTnI values at presentation and absolute changes within the first 2 h. RESULTS AMI was the final diagnosis in 17% of patients in the derivation and 13% in the validation cohort. The 2-h algorithm developed in the derivation cohort classified 56% of patients as rule-out, 17% as rule-in, and 27% as observation. Resulting diagnostic sensitivity and negative predictive value (NPV) were 99.2% and 99.8% for rule-out; specificity and positive predictive value (PPV) were 95.2% and 75.8% for rule-in. Applying the 2-h algorithm in the external validation cohort, 60% of patients were classified as rule-out, 13% as rule-in, and 27% as observation. Diagnostic sensitivity and NPV were 98.7% and 99.7% for rule-out; specificity and PPV were 97.4% and 82.2% for rule-in. Thirty-day survival was 100% for rule-out patients in both cohorts. CONCLUSIONS A simple algorithm incorporating hs-cTnI baseline values and absolute 2-h changes allowed a triage toward safe rule-out or accurate rule-in of AMI in the majority of patients.

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).

Evaluation of High-Sensitivity Cardiac Troponin I Levels in Patients With Suspected Acute Coronary Syndrome

IMPORTANCE Low concentrations of high-sensitivity cardiac troponin I determined on presentation to the emergency department (ED) have been shown to have an excellent negative predictive value (NPV) for the identification of acute myocardial infarction. The sensitivity, and therefore clinical applicability, of such testing strategies is unknown. OBJECTIVE To determine the diagnostic performance of low concentrations of high-sensitivity cardiac troponin I in patients with suspected cardiac chest pain and an electrocardiogram showing no ischemia as an indicator of acute myocardial infarction. DESIGN, SETTING, AND PARTICIPANTS A pooled analysis of 5 international (Australia, New Zealand, and England) prospective, observational cohort studies with blinded outcome assessment and 30-day follow-up was conducted. A total of 3155 patients presenting with symptoms suggestive of cardiac ischemia were included in the analysis. Eligible patients had a nonischemic electrocardiogram determined and high-sensitivity troponin I measured at presentation. The lower limit of detection (1.2 ng/L) as well as cutoff concentrations rounded to the nearest integer for a high-sensitivity troponin I assay were used in the analysis. Recruitment was undertaken from November 1, 2007, to August 10, 2013. MAIN OUTCOMES AND MEASURES The primary outcome was fatal or nonfatal acute myocardial infarction occurring within 30 days of ED presentation, adjudicated with serial troponin testing. The secondary outcome was the proportion of patients potentially suitable for early discharge at each cutoff concentration. RESULTS Of the 3155 eligible patients, 1771 were male (56.1%), and mean (SD) age was 57.4 (13.3) years. Acute myocardial infarction developed in 291 individuals (9.2%). The 1.2-ng/L limit of detection gave a sensitivity of 99.0% (95% CI, 96.8%-99.7%) and an NPV of 99.5% (95% CI, 98.4%-99.9%). This cutoff level would allow for early discharge of 594 patients (18.8%). All higher rounded cutoff values had sensitivities less than 98.0%. Diagnostic performance of the limit of detection was maintained when patients were stratified by age, sex, risk factors, presence of coronary artery disease, and early presentation. CONCLUSIONS AND RELEVANCE High-sensitivity troponin I concentrations determined at presentation to the ED that were below the limit of detection identified 18.8% of patients potentially suitable for discharge, with a high sensitivity for acute myocardial infarction. Rounded cutoff values above the limit of detection may not have the required sensitivity for clinical implementation.

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.

Comparison of Three Risk Stratification Rules for Predicting Patients With Acute Coronary Syndrome Presenting to an Australian Emergency Department

OBJECTIVES To compare the predictive ability of three risk stratification tools used to assess patients presenting to the ED with potential acute coronary syndrome. DESIGN Pre-planned analysis of an observational study. SETTING A single tertiary referral hospital. PARTICIPANTS 1495 patients presented with chest pain. 948 patients were screened and enrolled. Patients with at least 5 min of chest pain suggestive of ACS were eligible. INTERVENTIONS Subjects were risk categorised using the Heart Foundation of Australia/Cardiac Society of Australia and New Zealand guidelines (HFA/CSANZ), the TIMI score and the GRACE score. Three strata of the TIMI and GRACE score were used to compare to the HFA/CSANZ risk categories. MAIN OUTCOME MEASUREMENT 30-Day cardiac event rates including cardiac death, acute myocardial infarction and unstable angina. RESULTS There were 152 events in 91 patients (9.6%). The discriminatory ability of the scores determined by the AUC was 0.83 (95% CI 0.79-0.87) for the GRACE score, 0.79 (95% CI 0.74-0.83) for TIMI score and 0.75 (95% CI 0.70-0.80) for HFA/CSANZ. The AUCs with three strata of the GRACE and TIMI scores were 0.76 (95% CI 0.72-0.81) and 0.68 (95% CI 0.62-0.73) respectively. CONCLUSIONS All three scores were similar in performance in quantifying risk in ED patients with possible ACS. The GRACE score identified a sizable low risk cohort with high sensitivity and NPV but complexity of this tool may limit its utility. Improved scores are needed to allow early identification of low- and high-risk patients to support improvements in patient flow and ED overcrowding.

Effect of Pre-Hospital Ticagrelor During the First 24 h After Primary Percutaneous Coronary Intervention in Patients With ST-Segment Elevation Myocardial Infarction : The ATLANTIC-H24 Analysis

OBJECTIVES The aim of this landmark exploratory analysis, ATLANTIC-H(24), was to evaluate the effects of pre-hospital ticagrelor during the first 24 h after primary percutaneous coronary intervention (PCI) in the ATLANTIC (Administration of Ticagrelor in the cath Lab or in the Ambulance for New ST elevation myocardial infarction to open the Coronary artery) study. BACKGROUND The ATLANTIC trial in patients with ongoing ST-segment elevation myocardial infarction showed that pre-hospital ticagrelor was safe but did not improve pre-PCI coronary reperfusion compared with in-hospital ticagrelor. We hypothesized that the effect of pre-hospital ticagrelor may not have manifested until after PCI due to the rapid transfer time (31 min). METHODS The ATLANTIC-H(24) analysis included 1,629 patients who underwent PCI, evaluating platelet reactivity, Thrombolysis In Myocardial Infarction flow grade 3, ≥ 70% ST-segment elevation resolution, and clinical endpoints over the first 24 h. RESULTS Following PCI, largest between-group differences in platelet reactivity occurred at 1 to 6 h; coronary reperfusion rates numerically favored pre-hospital ticagrelor, and the degree of ST-segment elevation resolution was significantly greater in the pre-hospital group (median, 75.0% vs. 71.4%; p = 0.049). At 24 h, the composite ischemic endpoint was lower with pre-hospital ticagrelor (10.4% vs. 13.7%; p = 0.039), as were individual endpoints of definite stent thrombosis (p = 0.0078) and myocardial infarction (p = 0.031). All endpoints except death (1.1% vs. 0.2%; p = 0.048) favored pre-hospital ticagrelor, with no differences in bleeding events. CONCLUSIONS The effects of pre-hospital ticagrelor became apparent after PCI, with numerical differences in platelet reactivity and immediate post-PCI reperfusion, associated with reductions in ischemic endpoints, over the first 24 h, whereas there was a small excess of mortality. (Administration of Ticagrelor in the cath Lab or in the Ambulance for New ST elevation myocardial infarction to open the Coronary artery [ATLANTIC, NCT01347580]).

External validation of the emergency department assessment of chest pain score accelerated diagnostic pathway (EDACS-ADP)

Objective The emergency department assessment of chest pain score accelerated diagnostic pathway (EDACS-ADP) facilitates low-risk ED chest pain patients early to outpatient investigation. We aimed to validate this rule in a North American population. Methods We performed a retrospective validation of the EDACS-ADP using 763 chest pain patients who presented to St Pauls Hospital, Vancouver, Canada, between June 2000 and January 2003. Patients were classified as low risk if they had an EDACS <16, no new ischaemia on ECG and non-elevated serial 0-hour and 2-hour cardiac troponin concentrations. The primary outcome was the number of patients who had a predetermined major adverse cardiac event (MACE) at 30 days after presentation. Results Of the 763 patients, 317 (41.6%) were classified as low risk by the EDACS-ADP. The sensitivity, specificity, negative predictive value and positive predictive value of the EDACS-ADP for 30-day MACE were 100% (95% CI 94.2% to 100%), 46.4% (95% CI 42.6% to 50.2%), 100% (95% CI 98.5% to 100.0%) and 17.5% (95% CI 14.1% to 21.3%), respectively. Conclusions This study validated the EDACS-ADP in a novel context and supports its safe use in a North American population. It confirms that EDACS-ADP can facilitate progression to early outpatient investigation in up to 40% of ED chest pain patients within 2 hours.

Comparison of early biomarker strategies with the Heart Foundation of Australia/Cardiac Society of Australia and New Zealand guidelines for risk stratification of emergency department patients with chest pain.

To compare cardiac risk stratification using a 0 and 2 h point‐of‐care (POC) cardiac troponin (cTn), 0 and 2 h POC multi‐biomarkers against the 0 and 6 h laboratory cTn reference standard.