Accelerated diagnostic protocols using high-sensitivity troponin assays to rule in or out myocardial infarction: A systematic review

Background: Accelerated diagnostic protocols (ADPs) that incorporate high-sensitivity cardiac troponin (hs-cTn) can help emergency department (ED) providers quickly rule in or out acute myocardial infarction (AMI). Objectives: This systematic review evaluated the effectiveness and comparative effectiveness of clinically applied ADPs that use hs-cTn on clinical and health service use outcomes. Methods: Medline, Embase, ClinicalTrials.gov, and the Cochrane Database of Systematic Reviews were searched through May 2022. Standard systematic review methods were followed. Results: We found 17 eligible primary studies (reporting on 23 ADPs), including 2 randomized controlled trials (N ​= ​32,050), 5 nonrandomized comparative studies (N ​= ​18,377) and 10 single-group studies (N ​= ​44,016). One study compared an ADP with hs-cTn to hs-cTn alone, finding that the ADP increased discharges from the ED to the community and is not associated with worse clinical outcomes. Among 6 studies, ADPs with shorter compared to longer hs-cTn timing and ADPs that incorporated the HEART score compared to the TIMI score reduced ED length of stay and increased discharges to the community without resulting in worse clinical outcomes. Across studies, ADPs that measured hs-cTn for up to 12 ​h had longer ED lengths of stay than ADPs with ≤6 ​h of measurements. Conclusions: ADPs with shorter compared to longer hs-cTn timing reduce ED length of stay, increase discharges, and are not associated with changes in 30-day major adverse cardiovascular event, AMI, or mortality. Among ADPs that reduce ED length of stay, there is no obvious best choice, and any ADP should be tailored to local context.