Low High-Sensitivity Troponin Thresholds Identify Low-Risk Patients With Chest Pain Unlikely to Benefit From Further
James E Andruchow1, Timothy Boyne2, Grant Innes1,3
1Department of Emergency Medicine, University of Calgary, Calgary, Alberta, Canada.
Insights
Very low high-sensitivity cardiac troponin T (hs-cTnT) levels can rule out major adverse cardiac events (MACE) in chest pain patients. This finding suggests further risk stratification may be unnecessary for low-risk individuals.
Area of Science:
- Cardiology
- Emergency Medicine
- Biomarker Research
Background:
- High-sensitivity cardiac troponin T (hs-cTnT) is crucial for diagnosing acute myocardial infarction (AMI).
- The utility of very low hs-cTnT levels in predicting 30-day major adverse cardiac events (MACE) requires further investigation.
Purpose of the Study:
- To evaluate the sensitivity of low hs-cTnT concentrations in ruling out 30-day MACE.
- To assess the predictive value of hs-cTnT for MACE in patients with chest pain and nonischemic electrocardiograms.
Main Methods:
- Prospective cohort study of chest pain patients with nonischemic ECGs undergoing AMI rule-out.
- hs-cTnT assay used for initial assessment; primary outcome was 30-day MACE.
- Subgroup analysis conducted for patients with symptom onset >3 hours prior.
Main Results:
- Over one-third of patients had hs-cTnT below the limit of detection (5 ng/L).
- Presenting hs-cTnT < 5 ng/L demonstrated 94.4% sensitivity for 30-day MACE.
- In patients with symptom onset >3 hours, hs-cTnT < 5 ng/L showed 97.6% sensitivity for 30-day MACE and 100% for AMI.
Conclusions:
- Low hs-cTnT thresholds effectively identify patients at very low risk of 30-day MACE.
- Further risk stratification may offer limited value for low-risk patients presenting with nonischemic ECGs and low hs-cTnT.
Background:
Very low high-sensitivity cardiac troponin T (hs-cTnT) thresholds on presentation can rule out acute myocardial infarction (AMI), but the ability to identify patients at low risk of 30-day major adverse cardiac events (MACE) is less clear. This study examines the sensitivity of low concentrations of hs-cTnT on presentation to rule out 30-day MACE.
Methods:
This prospective cohort study enrolled patients with chest pain presenting to the emergency department with nonischemic electrocardiograms who underwent AMI rule-out with an hs-cTnT assay. The primary outcome was 30-day MACE; secondary outcomes were individual MACE components. Because guidelines recommend using a single hs-cTnT strategy only for patients with more than 3 hours since symptom onset, a subgroup analysis was performed for this population. Outcomes were adjudicated on the basis of review of medical records and telephone follow-up.
Results:
Of 1167 patients enrolled, 125 (10.7%) experienced 30-day MACE and 97 (8.3%) had AMI on the index visit. More than one-third of patients (35.6%) had presenting hs-cTnT concentrations below the limit of detection (5 ng/L), which was 94.4% (95% confidence interval [CI], 88.8-97.7) sensitive for 30-day MACE and 99.0% (95% CI, 94.5-100) sensitive for index AMI. Of 292 patients (25.0%) with hs-cTnT < 5 ng/L and at least 3 hours since symptom onset, only 3 experienced 30-day MACE (sensitivity 97.6%; 95% CI, 93.2-100) and none had AMI within 30 days (sensitivity 100%; 95% CI, 96.3-100).
Conclusions:
Among patients with nonischemic electrocardiograms and > 3 hours since symptom onset, low hs-cTnT thresholds on presentation confer a very low risk of 30-day MACE. In the absence of a high-risk clinical presentation, further risk stratification is likely to be low yield.
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