Written by Clay Smith
Use of a rapid rule-out MI protocol with hs-cTnT was safe, accurate, and would have reduced time to discharge and increased the proportion of patients ruled out in this U.S.-based implementation study.
Why does this matter?
Europe has been using high sensitivity troponin for quite some time. But the U.S. has only recently gotten FDA approval. How would such a protocol fare in the U.S.?
Head 'em up - rule 'em out
This was a prospective observational study at a single center with 563 patients presenting to the ED with need for MI rule-out. They compared hs-cTnT to standard troponin rule-out at 0 and 3 hours using a rapid rule out protocol (see figure). Adjudicated MI prevalence was 2.1%. More than half would have been ruled out at one hour with the new protocol. Sensitivity and NPV were both 100% for the hs-cTnT assay, though with wide confidence intervals. This is a promising protocol in a U.S. ED population and will need subsequent study to validate and implement safely. I really like this protocol because often patients have slightly elevated troponin levels with the high sensitivity assays. This protocol considers change in hs-cTnT from baseline to 1-hour and 1-hour to 3-hour, allowing classification as "ruled out" or "abnormal", needing more workup as opposed to the ESC 0/1 Algorithm limbo "Observe" category.
Evaluation of a Novel Rule-Out Myocardial Infarction Protocol Incorporating High-Sensitivity Troponin T in a US Hospital Circulation. 2018;138:00–00. DOI: 10.1161/CIRCULATIONAHA.118.033861
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Reviewed by Thomas Davis