For Doctors in a Hurry
- Researchers investigated whether the European Society of Cardiology 0/1-hour algorithm or the High-STEACS pathways provide superior diagnostic accuracy for NSTEMI.
- This prospective multicenter study evaluated 4,663 patients with acute chest discomfort and validated findings in an independent cohort of 2,485 patients.
- The 0/1-hour algorithm showed 100 percent sensitivity (95 percent CI: 99.4-100) while the 0/2-hour pathway ruled out 72.5 percent of patients.
- The researchers concluded that both algorithms perform well, though the 0/1-hour approach offers higher specificity and sensitivity for NSTEMI.
- Hospitals should select a high-sensitivity troponin pathway based on whether they prioritize diagnostic sensitivity or operational efficiency in the emergency department.
Optimizing Rapid Triage in Suspected Acute Coronary Syndrome
The rapid and reliable exclusion of myocardial infarction in the emergency department is a critical clinical priority to ensure patient safety and optimize hospital resources [1]. High-sensitivity cardiac troponin assays have transformed this process by allowing for much lower diagnostic thresholds than conventional tests, although this increased sensitivity often comes at the expense of specificity [2]. Current clinical practice guidelines recommend various accelerated diagnostic pathways, such as the 0/1-hour algorithm, which has demonstrated high negative predictive value in large observational meta-analyses [3]. However, the implementation of these high-sensitivity assays and their corresponding sex-specific thresholds remains complex, as clinicians must balance the need for rapid triage with the risk of underdiagnosing certain populations [4, 5]. To clarify these clinical trade-offs, a new multicenter study provides a direct comparison of the leading rapid diagnostic protocols, helping physicians choose the best pathway for their specific emergency department needs.
Direct Comparison of Rapid Diagnostic Pathways
The researchers conducted a prospective, international, multicenter diagnostic study to directly compare two leading triage strategies: the European Society of Cardiology 0/1-hour algorithm (ESC 0/1h-algorithm) and the High-STEACS 0/2-hour or 0/3-hour pathway (an alternative accelerated diagnostic protocol). This investigation utilized data from two major clinical trials (APACE and BACC). The discovery cohort comprised 4,663 eligible patients presenting to the emergency department with acute chest discomfort, with a median age of 61 years and a female representation of 32%. To ensure diagnostic accuracy, final diagnoses were centrally adjudicated by two independent cardiologists. The primary diagnostic endpoint was defined as non-ST-segment elevation myocardial infarction (NSTEMI) type 1, a myocardial infarction caused by a primary coronary event such as plaque rupture or erosion.
Within this discovery group, 663 patients (14.2%) were diagnosed with NSTEMI type 1. The study evaluated the performance of both diagnostic pathways using three distinct high-sensitivity cardiac troponin (hs-cTn) assays: hs-cTnI-Architect, hs-cTnI-Centaur/Atellica, and hs-cTnT-Elecsys. To confirm the robustness of the findings, the researchers performed an external validation in an independent prospective diagnostic study. This validation cohort included 2,485 patients with a median age of 64 years and 37% women. By testing these algorithms across different assays and patient populations, the study provides clinicians with a direct comparison of how these rapid protocols function in real-world emergency settings where the choice of assay may vary by institution.
Trade-offs Between Sensitivity and Rule-Out Efficacy
When evaluating the performance of the high-sensitivity cardiac troponin I (hs-cTnI) Architect assay, the researchers observed distinct differences in diagnostic accuracy between the two protocols. The ESC 0/1-hour algorithm achieved a sensitivity of 100% (95% CI: 99.4 to 100), effectively identifying every case of type 1 NSTEMI in the sample. In contrast, the High-STEACS 0/2-hour pathway demonstrated a lower sensitivity of 98.1% (95% CI: 96.7 to 99, P < 0.001). This statistical difference suggests that while both methods are highly effective, the ESC protocol offers a slight advantage in ensuring no myocardial infarctions are missed during the initial evaluation period.
The study also highlighted a significant trade-off regarding clinical efficacy, defined here as the proportion of patients who can be safely assigned to the rule-out group and potentially discharged from the emergency department. Using the hs-cTnI-Architect assay, the High-STEACS 0/2-hour pathway assigned 72.5% of patients to the rule-out group, whereas the ESC 0/1-hour algorithm ruled out only 52% of patients (P < 0.001). This indicates that the High-STEACS pathway is more efficient for hospital throughput by identifying a larger percentage of low-risk patients early in the triage process.
Beyond sensitivity and rule-out rates, the researchers found that the ESC 0/1-hour algorithm consistently maintained higher specificity for NSTEMI (the ability to correctly identify those without the condition) compared to the High-STEACS pathways across all high-sensitivity cardiac troponin assays tested. Despite these variations in specific metrics, the authors concluded that both algorithms exhibited comparable and excellent performance overall. When clinicians utilize high-sensitivity cardiac troponin I, the choice between protocols involves balancing the higher sensitivity of the ESC 0/1-hour algorithm against the higher efficacy and rule-out proportion of the High-STEACS pathways. For the practicing physician, this means institutional selection of a diagnostic pathway should be directly informed by whether the local clinical priority is maximizing the detection of every event or optimizing the speed of patient discharge.
Assay-Specific Variations and Validation
The researchers observed that the performance gap between the two diagnostic protocols was not uniform across all testing platforms. While the ESC 0/1-hour algorithm showed higher sensitivity and lower rule-out rates with the Architect assay, these differences in sensitivity and rule-out proportions were similar but less pronounced for the hs-cTnI-Centaur/Atellica assay. Notably, the choice of assay platform can eliminate these discrepancies entirely: the study found that differences in sensitivity and rule-out proportions were absent for the hs-cTnT-Elecsys assay. This suggests that for clinicians using high-sensitivity cardiac troponin T, the diagnostic performance and triage efficiency of the ESC and High-STEACS protocols are functionally equivalent in the emergency department setting.
To ensure the robustness of these observations, the authors extended their analysis beyond the two-hour mark to include longer observation windows. The findings were confirmed when comparing against the High-STEACS 0/3-hour pathways, indicating that the observed trade-offs between sensitivity and efficacy persist even when the High-STEACS protocol is extended to a three-hour interval. These results were further strengthened by an external validation cohort of 2,485 patients (median age: 64 years; 37% women), which mirrored the primary study results. By validating the data in an independent population, the researchers provide evidence that the higher sensitivity of the ESC protocol and the higher rule-out efficacy of the High-STEACS protocol are consistent features of these diagnostic pathways.
For the practicing physician, these data clarify the operational impact of protocol selection based on institutional needs. Hospitals prioritizing the highest possible sensitivity to avoid missing NSTEMI type 1 events may favor the ESC 0/1-hour algorithm, particularly when using troponin I assays. Conversely, institutions facing significant emergency department overcrowding may prioritize the High-STEACS pathway to maximize the proportion of patients safely ruled out and discharged. Ultimately, the study provides a validated framework for hospitals to select a high-sensitivity cardiac troponin pathway that aligns with their specific clinical and operational priorities, whether that is absolute diagnostic certainty or improved patient throughput.
References
1. Collet J, Thiele H, Barbato E, et al. 2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. European Heart Journal. 2020. doi:10.1093/eurheartj/ehaa575
2. Al-Saleh A, Alazzoni A, Shalash SA, et al. Performance of the high-sensitivity troponin assay in diagnosing acute myocardial infarction: systematic review and meta-analysis.. CMAJ open. 2014. doi:10.9778/cmajo.20130074
3. Nomura O, Hashiba K, Kikuchi M, et al. Performance of the 0-Hour/1-Hour Algorithm for Diagnosing Myocardial Infarction in Patients With Chest Pain in the Emergency Department - A Systematic Review and Meta-Analysis.. Circulation reports. 2022. doi:10.1253/circrep.CR-22-0001
4. Shah A, Anand A, Strachan FE, et al. High-sensitivity troponin in the evaluation of patients with suspected acute coronary syndrome: a stepped-wedge, cluster-randomised controlled trial. The Lancet. 2018. doi:10.1016/s0140-6736(18)31923-8
5. Khodor M, Vetrovec G, Moradi A, Malik B, Subbiondo RJ, zellner C. Abstract 4370630: Troponin Thresholds May Not Be Equal: A Systematic Review of Sex-Based Diagnostic Performance in NSTEMI. Circulation. 2025. doi:10.1161/circ.152.suppl_3.4370630
