Yield of high sensitivity troponin I in the diagnosis of cardiac disease in pediatric emergency department

Background: Troponin has long been used as a biomarker for cardiac disease. A new and more sensitive assay, high sensitive troponin I (hsTnI), is in use in Shaare Zedek since 2017. Little is known of its value as a marker for cardiac disease in the pediatric population.

Methods: We retrospectively analyzed all patients admitted to the pediatric emergency room who had hsTnI measured due to suspected cardiac disease, and assessed diagnosis and outcome. In our institution 6ng/L is detectable and 30ng/L is considered abnormal. Cardiac diagnosis was determined by a cardiologist blinded to the hsTnI values.

Results: Between 2017-2019, hsTnI was measured for 736 patients, 60% male, mean age 10 y. Ninety nine patients (13.5%) had detectable hsTnI (>6 ng/L), 66 patients (9%) were diagnosed with heart disease. Sixty seven percent, 44 of 66 patients with cardiac diagnosis had positive hsTnI. Eight percent, 57 of 672 patients without cardiac diagnosis had positive hsTnI.

The risk for cardiac disease with positive hsTnI (OR) was 20.6, P< 0.001. The area under the ROC curve for hsTnI and cardiac disease was 0.78 (CI 0.70-0.85).

No correlation was found between hsTnI levels and gender, age, blood pressure, temperature, O2 saturation, BUN, creatinine, or hemoglobin. hsTnI correlated with heart rate, CRP, RDW and weight.

hsTnI cut off for prediction of cardiac disease:

11 ng/L - negative predicting value 96.1%, positive predictive value 42.7 %

100 ng/L- negative predicting value 94.4%, positive predictive value 73.5 %.

Conclusion: hsTnI is highly correlated with cardiac disease in the pediatric emergency room. A small proportion of children with no heart disease have positive hsTni. Values of hsTnI > 100ng/L strongly suggest cardiac disease.