0/1-Hour vs 0/3-Hour Troponin Pathways in Suspected ACS

Key Takeaways

• The 0/1-hour pathway was not associated with a significant increase in discharge within 4 hours.
• The 0/1-hour pathway was noninferior for 30-day discharge safety among discharged patients considered not to have ACS.
• The authors attributed the limited operational advantage to central laboratory turnaround time and broader system constraints.

Among emergency department patients with suspected acute coronary syndrome, the ESC 0/1-hour troponin pathway did not clearly accelerate discharge compared with the 0/3-hour pathway. Discharge within 4 hours occurred in 21.8% and 19.2% of the groups, respectively (P = 0.07).

This pragmatic, randomized, noninferiority implementation trial compared clinician decision-making under ESC 0/1-hour and 0/3-hour high-sensitivity troponin pathways in patients with suspected ACS at 2 major emergency departments in North-West England. Patients were recruited between December 2021 and July 2024. Of 13,983 screened patients, 3,543 were recruited and consented, with a median age of 60 years and 53% men. Efficiency was defined as discharge within 4 hours, and safety was 30-day major adverse cardiac events among discharged patients considered not to have ACS. Independent hs-cTnI was used for formal adjudication with the fourth universal definition of myocardial infarction to avoid incorporation bias.

Among discharged patients considered not to have ACS, the 0/1-hour pathway was noninferior to the 0/3-hour pathway for discharge safety. The absolute difference in sensitivity was +4.2%, and the 1-sided 97.5% confidence interval lower bound was -2.5%, against a 3% noninferiority margin. Calculated sensitivities were 93.7% for the 0/1-hour pathway and 89.5% for the 0/3-hour pathway. Across the cohort, adjudicated index type 1 myocardial infarction occurred in 6.7%, and 30-day major adverse cardiac events occurred in 7.6% during follow-up. Investigators achieved 100% follow-up for all representations to any national hospital during the 30-day assessment.

The authors attributed the limited operational advantage to central laboratory turnaround time and broader system constraints rather than the shorter sampling interval alone. The hs-cTnT sample-to-result turnaround time was 81 minutes, with an interquartile range of 69 to 101 minutes. That explanation matched the modest efficiency difference between the randomized groups.

They also noted that discharge safety for both pathways was lower than observational work had suggested, while limiting that interpretation to this randomized setting. In the randomized comparison, the 0/1-hour pathway did not show a clear discharge-speed advantage, and discharge safety still met the noninferiority standard.