Performance of cardiac imaging and a new cardiomarker assay for early detection of myocardial injury in asphyxiated term neonates

ABSTRACT

Myocardial ischemia of newborns is a well known syndrome and is usually related to perinatal asphyxia. Recognition of myocardial ischaemia is more difficult in neonates than adults; it can be clinically occult, especially when hypoxia is mild. Cardiac troponin T [cTnT] is a cardiac specific marker that can be used for early detection of myocardial injury. This prospective observational study aimed to investigate the diagnostic values of cardiac troponin T [cTnT], electrocardiography [ECG] and echocardiography in early detection of myocardial injury in term asphyxiated neonates. This study included 44 term infants [24 neonates with asphyxia and 20 controls]. Term neonates with asphyxia had significantly higher cardiac troponin t concentration than control healthy neonates of 0.20 +/- 0.09 versus 0.04 +/- 0.02 ng/ml [p<0.05] respectively. Finally, five out of 24 asphyxiated term group [20.8%] died during the first week of life. Significant negative correlations were found between cardiac troponin t and umbilical blood pH, base excess and Apgar score [r = -0.67, -0.83, -0.79, respectively; p < 0.01]. ECG changes of grades 3 and 4 suggestive of myocardial ischemia are present only in asphyxiated group with incidence of 50%. Four out of five patients died had grade 4 and one had grade 3 ECG changes. However, in control group, normal ECG was found in 90% and only grade 1 ECG alterations in 10%. Regarding, echocardiographic findings, fractional shortening [FS] was significantly lower in asphyxiated neonates than the control group. There was no significant difference between both groups as regards to cardiac index and cardiac output. Tricuspid regurgitation was observed in 12 neonates [50%]. Seven [29%] asphyxiated neonates developed clinical signs of heart failure. A significantly higher serum cTnT was found in asphyxiated neonates with heart failure than those without heart failure [P < 0.05]. The sensitivity and specificity of serum cTnT in detecting myocardial injury presenting with heart failure was 71.4% and of 33.3%, respectively. It is concluded that Serum cTnT is a useful new cardiac biomarker that can be used for early detection and estimation of the incidence of myocardial injury in asphyxiated term neonates. Reduced fractional shortening and tricuspid insufficiency in Echocardiography and grades 3 and 4 ECG changes are important indicators of severe myocardial damage