Diagnostic accuracy of the T-MACS decision aid with a contemporary point-of-care troponin assay

Abstract

ObjectivesThe rapid turnaround time of point-of-care (POC) cardiac troponin (cTn) assays is highly attractive for crowded emergency departments (EDs). We evaluated the diagnostic accuracy of the Troponin-only Manchester Acute Coronary Syndromes (T-MACS) decision aid with a POC cTn assay.MethodsIn a prospective diagnostic accuracy study at eight EDs, we included patients with suspected acute coronary syndromes (ACS). Blood drawn on arrival and 3 hours later was analysed for POC cTnI (i-Stat, Abbott Point of Care). The primary outcome was a diagnosis of ACS, which included both an adjudicated diagnosis of acute myocardial infarction (AMI) based on serial laboratory cTn testing and major adverse cardiac events (death, AMI or coronary revascularisation) within 30 days.ResultsOf 716 patients included, 105 (14.7%) had ACS. Using serial POC cTnI concentrations over 3 hours could have ‘ruled out’ ACS in 198 (31.2%) patients with a sensitivity of 99.0% (95% CI 94.4% to 100.0%) and negative predictive value 99.5% (95% CI 96.5% to 99.9%). No AMIs were missed. T-MACS ‘ruled in’ ACS for 65 (10.4%) patients with a positive predictive value of 91.2% (95% CI 82.1% to 95.9%) and specificity 98.9% (97.6% to 99.6%).ConclusionWith a POC cTnI assay, T-MACS could ‘rule out’ ACS for approximately one-third of patients within 3 hours while ‘ruling in’ ACS for another 10%. The rapid turnaround time and portability of the POC assay make this an attractive pathway for use in crowded EDs or urgent care centres. Future work should also evaluate use in the prehospital environment.

Diagnostic accuracy of the Troponin-only Manchester Acute Coronary Syndromes (T-MACS) decision aid with a point-of-care cardiac troponin assay

“…We conducted the Alere Troponin at Three Hours (ATAT) study, a prospective diagnostic accuracy study at eight centres, nested within the larger Bedside Evaluation of Sensitive Troponin (BEST) study. Several separate evaluations from the BEST study have been published previously,10–13 including an evaluation of a different POC cTnI assay. However, the current work evaluating use of the T-MACS decision aid with the Alere cTnI assay has not been published.…”

“…The model has been validated with both high-sensitivity and contemporary laboratory-based cTn assays 7–9. In addition, we have recently published validation of T-MACS with a different POC cardiac troponin I (cTnI) assay (i-Stat, Abbott Point of Care) 10. In that study, T-MACS had adequate sensitivity but required the drawing of two blood samples 3 hours apart.…”

Prehospital Point-Of-Care Lactate Increases the Prognostic Accuracy of National Early Warning Score 2 for Early Risk Stratification of Mortality: Results of a Multicenter, Observational Study

“…Among all scores, the National Early Warning Score 2 (NEWS2) [6] has proven to be useful in the prehospital context, is validated, and commonly used internationally [7][8][9]. Moreover, technological development has led to the use of rapid-response point-of-care testing [10,11], as such is the case of prehospital lactate (pLA), which is a sensitive indicator of tissue hypoperfusion, reliable, and easy to obtain [12,13].…”

High-sensitivity cardiac troponin and the early rule out of myocardial infarction: time for action

“…There are a number of well-validated approaches which apply cardiac troponin as a continuous variable, all of which offer a magnitude improvement in safety over those using troponin as a binary variable at the 99th centile. [8][9][10] There are strengths and limitations of each, but the choice of algorithm is best determined at a local level in conjunction with both the clinical and laboratory service. The decision to admit or discharge will always be taken by a physician using all available clinical information, including the ECG, results from other investigations and the presence of ongoing symptoms.…”