A point-of-care troponin I threshold of <7ng/L combined with a non-ischaemic ECG and symptom duration ≥3 hours achieved a sensitivity of 0.99 (95% CI 0.95-1.00) for ruling out T1MI.
Cohort (n=2,943)
Blinded
Yes
Does the Siemens Atellica VTLi point-of-care troponin I assay at specific thresholds safely rule out type 1 NSTEMI in patients presenting to the ED?
A point-of-care high-sensitivity troponin I assay threshold of <7ng/L, combined with a non-ischaemic ECG and symptom duration ≥3 hours, safely rules out type 1 NSTEMI in 29% of ED patients.
Effect estimate: Sensitivity 0.99 (95% CI 0.95-1.00)
Abstract Background A combination of single sample rule out (SSRO) and point-of-care (POC) troponin testing, has the potential to reduce Emergency Department (ED) overcrowding. Previous studies have defined SSRO thresholds using the Siemens Atellica VTLi POC troponin I (VTLi POC) assay in non-European populations(1,2). Purpose To assess the performance of previously published thresholds for SSRO using the VTLi POC assay on a real-world population of patients presenting to the ED with suspected NSTEMI in the UK. Methods This was a nested cohort study of the Mersey Acute Coronary syndrome Rule Out Study-2, a dual-centre, randomised, implementation trial of the European Society of Cardiology 0/1 hour to 0/3 hour diagnostic pathway. Following consent and enrolment, whole blood lithium heparin samples were taken and immediately analysed on the VTLi POC assay in the ED by non-laboratory operators. Adjudication of type 1 non ST-elevation myocardial infarction (T1MI) occurred using an alternative central laboratory hs-cTnI assay (Abbott Alinity) by two consultant cardiologists, blinded to the results of the VTLi POC assay. Results A total of 2943 patients had presentation VTLi POC sample results and are included in the analysis for SSRO. The mean age was 59 years and 52% were male (Table 1). Figure 1 displays the sensitivity plot for increasing SSRO thresholds. At the threshold of 4ng/L the sensitivity (95% confidence interval) was impressive at 0.99 (0.96-1.00) with SSRO of 18% of the cohort. Sensitivity decreased to 0.97 (0.92-0.99) at a threshold of 7ng/L but the proportion suitable for SSRO increased to 50%. Combining the 7ng/L threshold with a non-ischaemic ECG and symptom duration of ≥ 3 hours improved the sensitivity to 0.99 (0.95-1.00) with 29% of the cohort fulfilling SSRO criteria. Conclusions The VTLi POC assay demonstrated impressive SSRO performance for index T1MI. The combination of a SSRO threshold of 7ng/L with a non-ischaemic ECG and a symptom onset of ≥ 3 hours at presentation provided the greatest balance of sensitivity and rule out potential.
Hatherley et al. (Sat,) conducted a cohort in suspected NSTEMI (n=2,943). VTLi POC troponin I assay vs. Central laboratory hs-cTnI assay was evaluated on Sensitivity for type 1 non ST-elevation myocardial infarction (T1MI) using a <7ng/L threshold, non-ischaemic ECG, and symptom duration ≥3 hours (Sensitivity 0.99, 95% CI 0.95-1.00). A point-of-care troponin I threshold of <7ng/L combined with a non-ischaemic ECG and symptom duration ≥3 hours achieved a sensitivity of 0.99 (95% CI 0.95-1.00) for ruling out T1MI.