Biochemical markers of cardiac injury in normal, surviving septic, or nonsurviving septic neonatal foals

The cardiac biomarkers cardiac troponin T (cTnT) and I (cTnI) and the cardiac isoenzyme of creatine kinase (CKMB) are used extensively in human medicine to diagnose and provide valuable prognostic information in patients with ischemic, traumatic, and septic myocardial injury. We designed a study to establish normal values for these markers in healthy, neonatal foals and to compare them with values obtained from septic neonates in a referral hospital population. The 25th, 50th, 75th, and 95th percentiles for cTnI and CKMB in the healthy-foal population were 0.08, 0.14, 0.25, 0.49 ng/mL and 1.4, 2.3, 4.0, 7.4 ng/mL, respectively. The values obtained for cTnT were frequently (43/52 foals; 83%) below the lower limit of detection of the assay (0.009 ng/mL), but the median and range were 0.009 and 0.009-0.041 ng/mL, respectively. In the septic foal population, the 25th, 50th, 75th, and 95th percentile values for cTnI and CKMB were 0.05, 0.12, 0.22, and 1.10 ng/mL and 2.0, 4.4, 7.8, and 24 ng/mL, respectively. The values obtained for cTnT were less frequently below the lower limit of detection (23/38 foals; 60%) compared with the healthy foal population, and the median and range were 0.009 and 0.009-0.20 ng/mL, respectively. Significantly higher values were observed for cTnT and CKMB in septic foals compared with the healthy neonatal foal population, but there were no differences among septic foals in survivors compared with nonsurvivors. These findings suggest that myocardial injury occurs during septicemia in neonatal foals but that the injury is not associated with survival among septic foals.