Improving Care with the First measurement of high-sensitivity troponin T (ICare-FirsT) to enable early rule out and reduce length of stay: a diagnostic and observational study

BACKGROUND: Pathways incorporating clinical risk assessment, ECG and serial troponin measurements for the assessment of patients with possible myocardial infarction (MI) in the ED are standard practice. Incorporating a single troponin test to stratify to low risk of MI using a baseline measurement of cardiac troponin (cTn) with a high-sensitivity T assay (hs-cTnT) is recommended. We aimed to implement a pathway incorporating a single-test component and measure the impact on length of stay (LOS). METHODS: There were two study phases: (1) Development and performance assessment of a novel pathway incorporating a single-test hs-cTnT stratification using high-fidelity research data, (2) An audit of the implementation of a single-test Roche hs-cTnT strategy within multiple EDs. The low-risk threshold used for hs-cTnT was 5 ng/L. The safety metric was MI or death not known to be non-cardiac within 30 days (MACE30). RESULTS: Phase I: The derived pathway had 16.3% low risk after one blood draw ≥3 hours from symptom onset with hs-cTnT <5 ng/L, non-ischaemic ECG and ED Assessment of Chest pain Score <21. PHASE II: In six hospitals, there were 10 912 patients in the control arm and 13 997 after implementation of single-test hs-cTnT. The unadjusted estimated mean reduction in LOS after intervention was 1.6% (95% CI 0.4% to 2.9%). After adjustment accounting for increased presentations, this was 8.5% (95% CI 7.7% to 9.3%). CONCLUSIONS: Within clinical pathways, a single test with a result from an hs-cTnT of <5 ng/L as a component resulted in a small, but meaningful, reduction in mean ED LOS.