Health Care Resource Utilization: A Cluster Randomized Trial of a Rapid, High-Sensitivity Cardiac Troponin Protocol

Document Type

Conference Proceeding

Publication Date


Publication Title

Academic Emergency Medicine


Background and Objectives: Data on the impact of new rapid rule-out protocols using high sensitivity cardiac troponin I (hs-cTnI) in the US is lacking. We compared healthcare resource utilization between a traditional protocol and a new 0/1-hour, hs-cTnI protocol for exclusion of acute myocardial infarction (AMI).

Methods: A pragmatic, stepped wedge, randomized trial of patients evaluated for possible AMI in 9 emergency departments (ED) from 7/2020-3/2021. The trial arms included a new 0/1-hour rapid protocol and standard care. Randomization occurred by ED site. We included all adult ED patients for whom the treating clinician ordered an ECG and cardiac troponin. We excluded patients with STEMI, any hs-cTnI >18 ng/L in the ED, or a traumatic cause of symptoms. In the rapid protocol, MI was excluded, and ED discharge advised if hs-cTnI < 4 ng/L at time 0, or =4 ng/L at time 0 with 1 hour < 8 ng/L. In standard care, troponin was measured at 0 and 3 hours, clinicians were blinded to values ≤18 ng/L, and ≤18 ng/L was used to exclude AMI and guide ED discharge. Outcomes included ED discharge and observation rates, length of stay, and cardiac testing. The analysis included a mixed effect model adjusting for ED site, time, sex, age, and race. We report adjusted odds ratios (aOR) with 95% confidence intervals (CI).

Results: There were 32,609 patients, of whom 13,505 were in the standard care and 19,104 in the rapid protocol arms. Unadjusted ED discharge rates were lower under the rapid protocol (58.0%) vs. standard care (59.8%). The proportion of patients receiving cardiac stress testing (4.0% vs. 3.4%) and coronary catheterization (1.3% vs. 1.0%) fell under the rapid protocol. In adjusted analysis, there was no statistically significant difference in rates of ED discharge (aOR 1.03, 95% CI 0.94-1.13) with the rapid protocol. There was a reduction in the odds of observation placement (aOR 0.90, 95% CI 0.82-0.99) as well as a reduced overall length of stay for patients discharged from the ED or observation unit (aOR 0.95, 95% CI 0.91–0.99) under the rapid protocol. The difference in odds of coronary catheterization was not statistically significant (aOR 0.83, 95% CI 0.36 – 1.86), but there were reduced odds of cardiac stress testing under the rapid protocol (aOR 0.71, 95% CI 0.53 – 0.95).

Conclusion: Implementation of a rapid 0/1-hour protocol to evaluate for AMI in the ED was associated with modest reductions in healthcare resource utilization.





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