High-Sensitivity Troponin and the Application of Risk Stratification Thresholds in Patients With Suspected Acute Coronary Syndrome
Why the study?
Guidelines acknowledge the emerging role of hs-cTnI for risk stratification and early rule-out of myocardial infarction, but multiple thresholds have been described.
Do high-sensitivity troponin I thresholds of <5 ng/L or <2 ng/L safely rule out myocardial infarction or cardiac death at 30 days in patients with suspected acute coronary syndrome?
Population
32 837 consecutive patients with suspected acute coronary syndrome across 10 hospitals in Scotland
Comparison
Limit of detection (<2 ng/L) vs optimized threshold (<5 ng/L)
Design
Prespecified secondary and observational multicenter trial analysis
Follow-up
12 months
Authors
Discussion
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Member takes
Implication
Supports hs-TnI thresholds for rule-out in suspected ACS; extends observational data but leaves open randomized validation.
Key Points
- To assess the safety and efficacy of high-sensitivity cardiac troponin I risk stratification thresholds (<2 ng/L and <5 ng/L) for rapidly ruling out myocardial infarction in suspected acute coronary syndrome.
- Secondary analysis of a multicenter trial (NCT01852123) across 10 Scottish hospitals enrolling 48,282 consecutive patients with suspected acute coronary syndrome, analyzing 32,837 eligible individuals.
- Evaluated Abbott high-sensitivity troponin I assay thresholds of <2 ng/L and <5 ng/L in patients with >2 hours of symptoms, excluding presentation myocardial injury or ST-segment elevation myocardial infarction.
- Primary outcome was negative predictive value for 30-day myocardial infarction or cardiac death; secondary outcome was 12-month myocardial infarction or cardiac death modeled via multivariable logistic regression.
- Concentrations of <5 ng/L and <2 ng/L classified 71% (23,260/32,837) and 39% (12,716/32,837) of patients as low risk, achieving negative predictive values for 30-day myocardial infarction or cardiac death of 99.8% (95% CI, 99.7%–99.8%) and 99.9% (95% CI, 99.8%–99.9%), respectively.
- Compared with concentrations from ≥5 ng/L to the 99th centile, 12-month myocardial infarction or cardiac death was markedly lower for patients with troponin <5 ng/L (0.7% vs 5.3%; adjusted OR, 0.23 [95% CI, 0.19–0.28]) and <2 ng/L (0.3% vs 5.3%; adjusted OR, 0.20 [95% CI, 0.14–0.29]).
Structured PICO
Do high-sensitivity troponin I thresholds of <5 ng/L or <2 ng/L safely rule out myocardial infarction or cardiac death at 30 days in patients with suspected acute coronary syndrome?
P
Population
32,837 consecutive patients with suspected acute coronary syndrome and >2 hours of symptoms, mean age 61±17 years, 47% female, across 10 hospitals in Scotland. Excluded: myocardial injury at presentation, ≤2 hours of symptoms, or ST-segment elevation myocardial infarction.
I
Intervention
High-sensitivity cardiac troponin I (hs-cTnI) risk stratification threshold of <5 ng/L (optimized threshold) or <2 ng/L (limit of detection) at presentation.
C
Comparator
Patients with hs-cTnI concentrations of ≥5 ng/L but <99th centile.
O
Outcome
Negative predictive value for a composite of myocardial infarction or cardiac death within 30 days.composite
High-sensitivity troponin I thresholds of <5 ng/L and <2 ng/L both provide excellent negative predictive value (>99.8%) for safely ruling out 30-day myocardial infarction or cardiac death in suspected ACS patients with at least 2 hours of symptoms.
Cite This Study
Bularga et al. (2019) studied this question.