Accelerated Diagnostic Pathways for Suspected ACS in Practice: Randomized Trial of 0/1-Hour vs 0/3-Hour Troponin Testing

Accelerated Diagnostic Pathways for Suspected ACS in Practice: Randomized Trial of 0/1-Hour vs 0/3-Hour Troponin Testing

Authors: Hatherley J, Dakshi A, Collinson P, Miller G, Bailey L, Davies S, Fearon H, Meah N, Frost F, Raj R, Ensor E, Fisher M, Goulden C, Noori Z, Salmon T, Rawat A, Hornby R, Lambert A, Sekulska K, Ingram T, Fitzgerald G, Shaw M, Khand A
Journal: Journal of the American College of Cardiology, May 2026

Conclusions:

  • In real-world ED practice, implementing the ESC 0/1-hour hs-troponin pathway did not significantly increase discharge within 4 hours compared with a 0/3-hour pathway.

  • The 0/1-hour pathway was noninferior for safety compared with 0/3-hour testing among discharged patients.

  • The expected operational advantage of faster sampling was blunted by central lab turnaround time and broader system constraints.

  • Practical takeaway: a 0/1-hour algorithm is only as fast as the lab and disposition system supporting it. Without rapid assay turnaround and functional downstream processes, shortening the sampling interval may not meaningfully improve ED throughput.

Practice Takeaways:

  • The study supports the safety of 0/1-hour testing relative to 0/3-hour testing, but the operational benefit may be modest unless your ED has rapid troponin turnaround.

  • If your lab turnaround time is around an hour or longer, the theoretical advantage of a 0/1-hour protocol may disappear.

  • Accelerated diagnostic pathways are not just troponin algorithms; they depend on:

    • Time to ECG

    • Time to phlebotomy

    • Lab processing time

    • Provider reassessment

    • Disposition decision-making

    • Availability of follow-up

  • The discharge-within-4-hours rate was low in both arms, reminding us that chest pain throughput is often limited by system flow rather than the second troponin draw alone.

  • The sensitivities in this pragmatic trial were lower than those reported in many observational studies, which should temper overconfidence when applying these pathways at scale.

  • For ED leadership, the lesson is clear: before switching pathways to improve flow, measure your actual sample-to-result time and door-to-disposition bottlenecks.

Results:

  • Population: 3,543 consented patients with suspected ACS from 2 large EDs in North-West England.

  • Screened: 13,983 patients from December 2021 to July 2024.

  • Follow-up: 100% follow-up for representations to any national hospital.

  • Median age: 60 years.

  • Sex: 53% male.

  • Adjudicated index type 1 MI: 6.7%.

  • 30-day MACE: 7.6%.

  • Central laboratory hs-cTnT turnaround time: median 81 minutes from sample to result.

  • Discharge within 4 hours:

    • 0/1-hour pathway: 21.8%

    • 0/3-hour pathway: 19.2%

    • Difference did not reach statistical significance (p = 0.07).

  • Safety among discharged patients:

    • 0/1-hour pathway was noninferior to the 0/3-hour pathway.

    • Absolute difference in sensitivity: +4.2% in favor of 0/1-hour.

    • 1-sided 97.5% CI lower bound: −2.5%, meeting the prespecified noninferiority margin of 3%.

  • Calculated sensitivities:

    • 0/1-hour: 93.7% (95% CI 88.4%–97.1%)

    • 0/3-hour: 89.5% (95% CI 82.7%–94.3%)

Methods:

  • Pragmatic randomized noninferiority implementation trial comparing:

    • ESC 0/1-hour hs-troponin accelerated diagnostic pathway.

    • 0/3-hour hs-troponin pathway.

  • Conducted in 2 major emergency departments in North-West England.

  • Trial period: December 2021 to July 2024.

  • Included patients presenting with suspected ACS.

  • Efficiency outcome:

    • Proportion of patients discharged within 4 hours.

  • Safety outcome:

    • 30-day MACE among patients considered not to have ACS and discharged.

    • MACE included adjudicated index or representation type 1 MI, cardiovascular death, and urgent coronary revascularization.

  • To reduce incorporation bias, formal MI adjudication used an independent hs-cTnI assay and the Fourth Universal Definition of MI.

  • Noninferiority margin:

    • Absolute difference in sensitivity of 3%, assessed with a 1-sided 97.5% CI.

Hatherley, J., Dakshi, A., Collinson, P., Miller, G., Bailey, L., Davies, S., Fearon, H., Meah, N., Frost, F., Raj, R. and Ensor, E., 2026. Accelerated diagnostic pathways for suspected acute coronary syndrome in practice: a randomized trial of 0/1-hour vs 0/3-hour troponin testing. JACC.

 

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