LEGEND Trial: A Game-Changer in Rapid Rule-Out of Acute Myocardial Infarction in the ED

Highlights

The LEGEND trial found that a high-sensitivity troponin-based rule-out strategy reduced hospital length of stay by 3.6 hours, increased early discharges by 22.9%, and decreased cardiac testing by 7.8% without compromising patient safety.

Background

Acute coronary syndrome (ACS) remains a leading cause of emergency department presentations worldwide. While most patients with chest pain don’t have ACS, current diagnostic pathways often require prolonged observation and extensive testing. High-sensitivity cardiac troponin assays have revolutionized ACS diagnostics, but optimal implementation strategies are needed to maximize their clinical impact.

Study Design

LEGEND was a stepped-wedge cluster randomized controlled trial conducted across 4 Australian emergency departments from August 2019 to July 2020. The study included 9,944 adult patients presenting with suspected ACS. Sites were randomized to implement the LEGEND strategy, which combined high-sensitivity troponin assay results (≤2 ng/L) with shared decision-making. The primary outcome was length of stay, with secondary outcomes including discharge within 4 hours, cardiac testing rates, and safety endpoints.

Key Findings

For patients with troponin ≤2 ng/L (the LEGEND cohort), the intervention reduced mean length of stay by 3.6 hours (95% CI 2.5 to 4.6 hours) compared to standard care. Early discharges increased by 22.9% (95% CI 19.5% to 26.3%), and cardiac testing decreased by 7.8% (95% CI 4.6% to 11.1%). Crucially, there were no differences in representations, index events, or 30-day adverse events between groups, demonstrating the strategy’s safety.

Expert Commentary

The LEGEND trial provides strong evidence for implementing high-sensitivity troponin-based rule-out pathways in emergency departments. The study’s stepped-wedge design allowed for robust evaluation in real-world clinical practice across multiple centers. While the results are promising, some experts note that wider adoption may require additional validation in diverse healthcare systems and consideration of local resource constraints.

Conclusion

The LEGEND strategy represents a significant advance in emergency cardiovascular care, offering a safe, efficient approach to ruling out acute myocardial infarction. By reducing length of stay and unnecessary testing, this protocol has the potential to alleviate emergency department overcrowding while maintaining patient safety. Future research should explore long-term outcomes and cost-effectiveness of this approach.

Funding and Registration

The study was supported by the National Health and Medical Research Council of Australia. ClinicalTrials.gov registration number was not provided in the publication.