Cord blood cardiac troponin I as an early predictor of short-term outcome in perinatal hypoxia

Background: In most perinatal-hypoxia survivors, myocardial dysfunction can be reversed with appropriate inotropic support and oxygenation. The main problem related to outcome is cerebral damage.

Objective: We tested the hypothesis that cardiac troponin I (cTnI), a known marker of myocardial injury, is also an early predictor of severity of cerebral damage and mortality in intrauterine hypoxia.

Methods: Venous and arterial cord blood samples were collected at delivery from 54 consecutive newborns with hypoxic-ischemic encephalopathy and from 50 consecutive healthy controls. Arterial blood gas analysis was performed and levels of cTnI, creatine kinase and creatine kinase-MB in venous cord blood were measured. The same serum parameters were also measured on the 3rd and 7th day of life.

Results: Infants with hypoxia had a significantly higher cord blood cTnI levels than controls (p < 0.0001). Cord blood and 3rd and 7th day serum cTnI values showed a significant increase with severity of HIE (p < 0.0001). In non-survivors cord blood cTnI levels were significantly higher than the survivors (5.9 ng/ml, range 2.1-12.8, and 1.6 ng/ml, range 0.4-5.8, respectively; p < 0.0001). Receiver-operator curve analysis revealed cord cTnI as the most sensitive factor for predicting early death (area under curve = 0.956; SE: 0.028; 95% CI: 0.9-1.01). Cord blood cTnI of 4.6 ng/ml was identified as the optimal cut-off level for predicting serious risk of early mortality.

Conclusion: The results suggest that significant elevation of cord cTnI is an excellent early predictor of severity of hypoxic-ischemic encephalopathy and mortality in term infants.