The Diagnostic Value of Both Troponin T and Creatinine Kinase Isoenzyme (CK-MB) in Detecting Combined Renal and Myocardial Injuries in Asphyxiated Infants

BACKGROUND: Troponin T (cTnT) and Creatinine Kinase Isoenzyme (CK-MB) are both markers of myocardial injuries. However, CK-MB is also elevated in acute kidney injury. OBJECTIVE: The diagnostic value of both cTnT and cardiac CK-MB in combined myocardial and acute kidney injuries (AKI) in asphyxiated neonates was evaluated. METHOD: 40 asphyxiated infants and 40 non-asphyxiated controls were consecutively recruited. Serum levels of cTnT, CK-MB and creatinine were measured. Myocardial injury and AKI were defined as cTnT >95(th) percentile of the control and serum creatinine >1.0 mg/dl respectively. RESULTS: Of the 40 subjects, 9 (22.50%), 8 (20.00%) and 4 (10.00%) had myocardial injury, AKI and combined AKI and myocardial injuries respectively. The mean cTnT and CK-MB values were highest in infants with combined AKI and myocardial injuries. The Mean cTnT in infants with AKI, myocardial injury and combined AKI and myocardial injuries were 0.010±0.0007 ng/ml, 0.067±0.040 ng/ml and 0.084±0.067 ng/ml respectively, p = 0.006. The mean CK-MB in infants with AKI, myocardial injury and combined AKI and myocardial injuries were 2.78±0.22 ng/ml, 1.28±0.11 ng/ml and 4.58±0.52 ng/ml respectively, p = <0.0001. CONCLUSION: In severe perinatal asphyxia, renal and myocardial injuries could co-exist. Elevated cTnT signifies the presence of myocardial injury. Elevated CK-MB indicates either myocardial injury, AKI or both. Therefore renal injury should be excluded in asphyxiated infants with elevated CK-MB.