P2.013: Natural History of Troponin I Elevation in Pediatric Emergency Room Patients

Background: Since emergence of COVID-19, and its association with myocarditis, the use of troponin I (TnI) tests has drastically increased at pediatric ERs. We hypothesize that in pediatric patients presenting to the ER, the natural history of trivially elevated troponin is normal without cardiac disease. Additionally, we hypothesized there exists a cut-off troponin value with good sensitivity and specificity.

Methods: We conducted a single-center retrospective study of patients who were presented to our ER 2022-2023 found to have elevated troponin levels (hospital assay defines abnormal > 0.021 ng/mL) and the following chief complaints: chest pain, dizziness, syncope/near-syncope, fatigue, shortness of breath, and palpitations. Patients without elevated troponin or follow-up cardiac testing (echocardiogram, ECG) were excluded. Patients with a prior history of cardiac disease were excluded. We compared patients found to have no cardiac disease with those who did. Cardiac disease was defined as an abnormality on ECG, echo, or MRI (if available). Comparisons were made using chi-square and independent t-tests. Receiver operating curve (ROC) analysis to determine discriminatory ability of troponin. Youden's J statistic determined point of highest sensitivity and specificity.

Results: In total, 275 patients met inclusion criteria for chief complaint and elevated troponin, though 103 had incomplete cardiac testing, leaving 172 patients for analysis. Of these, 29 (17%) were diagnosed with cardiac disease and 143 (83%) without cardiac disease (Table). There was a lesser incidence of female sex in the cardiac disease group. Those with cardiac disease had a significantly greater troponin value at presentation (10.0 +/- 12.1 vs. 0.35 +/- 1.5, p < 0.001). MRI was only available for 17 patients total (10%).

ROC analysis demonstrated excellent discriminatory ability for troponin at ER presentation for detection of cardiac disease (Figure, area under curve 0.95, p < 0.001). Youden’s J determined a cut-off troponin value of 0.3 for sensitivity 90% and specificity 86%. There were 47 patients with a troponin > 0.3, and 125 < 0.3. A troponin > 0.3 yielded a positive predictive value of 55%, while < 0.3 yielded a negative predictive value of 98%. Those with troponin < 0.3 were admitted 70% of the time, and >0.3 admitted 83%.

Conclusion: Troponin level at ER presentation demonstrates good discriminatory ability for subsequent cardiac disease diagnosis. Low troponin levels ( < 0.3) have a high negative predictive value, however a significant number of patients were admitted to the hospital. This initial data may guide appropriate triaging and resource utilization.