Long-term safety and effectiveness of the ESC 0h/1h troponin protocol in routine clinical care

Background Chest pain is a frequent cause of Emergency Department (ED) attendance, yet only a minority are diagnosed with acute coronary syndrome (ACS). Concern about missed ACS often leads to extensive testing and admissions, highlighting the need for efficient diagnostic strategies. High-sensitivity cardiac troponin assays enable rapid rule-out of acute myocardial infarction using the ESC-recommended 0h/1h algorithm. However, evidence is limited on whether performance is sustained after support cessation. Purpose To evaluate the safety and effectiveness of the ESC 0h/1h high-sensitivity cardiac troponin T (hs-cTnT) algorithm one year after implementation, during routine clinical use without continued educational support. Methods This observational cohort study included adult patients with non-traumatic chest pain presenting to three EDs in Sweden. The ESC 0h/1h hs-cTnT protocol was implemented in 2018 with structured educational support, including staff training and reminders to ensure 1-hour sampling and algorithm use. Patients presenting February–November 2019, when the protocol remained available as a local guideline without educational reinforcement, were compared with a prospectively enrolled 2018 cohort using identical inclusion criteria. The protocol was applied alongside clinical assessment and electrocardiogram (ECG), with risk stratification into low, intermediate, and high ACS risk. Primary outcomes were 30-day myocardial infarction or all-cause death among discharged patients and ED length of stay. Secondary outcomes included discharge rates, 30-day revisits, and resource utilization among patients without ACS. Outcomes were compared using regression models adjusted for age, diabetes, and prior myocardial infarction. Results A total of 15,661 ED visits were included (2018: n=6,993; 2019: n=8,668), with similar baseline characteristics. Key outcomes are in Table 1. Among discharged patients, 30-day acute myocardial infarction or all-cause death remained rare and did not increase in 2019 (2018: 0.4% [19/4,917] vs 2019: 0.3% [18/6,339]; adjusted odds ratio (OR) 0.72, 95% confidence interval (CI) 0.38–1.39, p=0.33). Median ED length of stay among discharged patients increased modestly from 266 (IQR 197–375) to 276 minutes (Interquartile range [IQR] 206–390). The proportion of patients discharged increased significantly in 2019 (73.1% vs 70.3%; adjusted OR 1.11, 95% CI 1.03–1.20). Discharge rates increased across all risk strata, while 30-day acute myocardial infarction or death among discharged patients remained low in each group. Conclusion One year after implementation and without continued educational reinforcement, the ESC 0h/1h hs-cTnT protocol remained safe, with very low 30-day acute myocardial infarction or death rates among discharged patients. ED length of stay increased modestly, while discharge rates increased across risk strata without evidence of compromised safety.