Point-of-care high-sensitivity cardiac troponin in suspected acute myocardial infarction assessed at baseline and 2†h.

BACKGROUND AND AIMS: Strategies to assess patients with suspected acute myocardial infarction (AMI) using a point-of-care (POC) high-sensitivity cardiac troponin I (hs-cTnI) assay may expedite emergency care. A 2-h POC hs-cTnI strategy for emergency patients with suspected AMI was derived and validated. METHODS: In two international, multi-centre, prospective, observational studies of adult emergency patients (1486 derivation cohort and 1796 validation cohort) with suspected AMI, hs-cTnI (Siemens Atellica® VTLi) was measured at admission and 2 h later. Adjudicated final diagnoses utilized the hs-cTn assay in clinical use. A risk stratification algorithm was derived and validated. The primary diagnostic outcome was index AMI (Types 1 and 2). The primary safety outcome was 30-day major adverse cardiac events incorporating AMI and cardiac death. RESULTS: Overall, 81 (5.5%) and 88 (4.9%) patients in the derivation and validation cohorts, respectively, had AMI. The 2-h algorithm defined 66.1% as low risk with a sensitivity of 98.8% [95% confidence interval (CI) 89.3%-99.9%] and a negative predictive value of 99.9 (95% CI 99.2%-100%) for index AMI in the derivation cohort. In the validation cohort, 53.3% were low risk with a sensitivity of 98.9% (95% CI 92.4%-99.8%) and a negative predictive value of 99.9% (95% CI 99.3%-100%) for index AMI. The high-risk metrics identified 5.4% of patients with a specificity of 98.5% (95% CI 96.6%-99.4%) and a positive predictive value of 74.5% (95% CI 62.7%-83.6%) for index AMI. CONCLUSIONS: A 2-h algorithm using a POC hs-cTnI concentration enables safe and efficient risk assessment of patients with suspected AMI. The short turnaround time of POC testing may support significant efficiencies in the management of the large proportion of emergency patients with suspected AMI.

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.

Clinical characteristics of Aboriginal and Torres Strait Islander emergency department patients with suspected acute coronary syndrome.

OBJECTIVES: To describe the demographics, presentation characteristics, clinical features and cardiac outcomes for Aboriginal and Torres Strait Islander patients who present to a regional cardiac referral centre ED with suspected acute coronary syndrome (ACS). METHODS: This was a single-centre observational study conducted at a regional referral hospital in Far North Queensland, Australia from November 2017 to September 2018 and January 2019 to December 2019. Study participants were 278 Aboriginal and Torres Strait Islander people presenting to an ED and investigated for suspected ACS. The main outcome measure was the proportion of patients with ACS at index presentation and differences in characteristics between those with and without ACS. RESULTS: ACS at presentation was diagnosed in 38.1% of patients (n = 106). The mean age of patients with ACS was 53.5 years (SD 9.5) compared with 48.7 years (SD 12.1) in those without ACS (P = 0.001). Patients with ACS were more likely to be male (63.2% vs 39.0%, P < 0.001), smokers (70.6% vs 52.3%, P = 0.002), have diabetes (56.6% vs 38.4%, P = 0.003) and have renal impairment (24.5% vs 10.5%, P = 0.002). CONCLUSIONS: Aboriginal and Torres Strait Islander patients with suspected ACS have a high burden of traditional cardiac risk factors, regardless of whether they are eventually diagnosed with ACS. These patients may benefit from assessment for coronary artery disease regardless of age at presentation.

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 Assessment of Suspected Acute Coronary Syndrome Using the IMPACT Pathway in Aboriginal and Torres Strait Islander People.

OBJECTIVES: The Improved Assessment of Chest pain Trial (IMPACT) pathway is an accelerated strategy for the assessment of emergency patients presenting with suspected acute coronary syndrome (ACS). The objective of this study was to report outcomes for Aboriginal and Torres Strait Islander patients deemed low-, intermediate-, or high-risk according to this pathway. DESIGN: This was a prospective observational trial conducted between November 2017 and December 2019. SETTING: Regional hospital in Far North Queensland. PARTICIPANTS: Aboriginal and Torres Strait Islander people presenting to the Emergency Department with suspected ACS were asked to participate. Participants were stratified as low-, intermediate- or high-risk of ACS according to the IMPACT pathway. High-and intermediate risk patients were managed according to the IMPACT pathway. Management of low-risk patients included additional inpatient cardiac testing, which was not part of the original IMPACT pathway. MAIN OUTCOME MEASURES: The primary outcome was acute coronary syndrome within 30-days. Secondary outcomes included length of stay and prevalence of objective testing. RESULTS: A total of 155 participants were classified as either at low-risk (n=18 11.6%), intermediate-risk (n=87 56.1%), or high-risk (n=50 32.3%) of ACS. Thirty-day (30-day) ACS occurred in 29 (18.6%) patients, which included 26 (52.0%) high-risk patients and three (3.4%) intermediate-risk patients. No patients in the low-risk group were diagnosed with ACS during their index presentation or by 30-days. Median hospital length-of-stay was 11.9 hours (interquartile range [IQR] 5.3-20.2 hrs) for low- and 15.5 hours (IQR 5.9-29.2 hrs) for intermediate-risk patients. CONCLUSION: The IMPACT pathway, which has been associated with reduced LOS in other settings, could be safely implemented for patients of Aboriginal and Torres Strait Islander origin, classifying two-thirds as low- or intermediate risk. However, a clinically significant proportion of Aboriginal and Torres Strait Islander patients experience cardiac events, which supports the need to provide early objective testing for coronary artery disease.