N-Terminal Pro-B-Type and Cardiac Troponin T Levels for Monitoring Effectiveness of Treatment in Very Low Birth Weight Infants With Hemodynamic Instability

NT-proBNP is a member of the natriuretic hormone family which plays an important role in regulation of extracellular fluid volume and blood pressure.It is secreted from the cardiac ventricle myocytes in response to myocardial stress. This hormone serves as a marker of ventricular dysfunction in adults but its role in newborns and especially preterm infants has not been well studied yet. Following birth of a healthy infant there is a surge in NT-proBNP levels which is then followed by a rapid decrease. One explanation for this surge is the transition in hemodynamics from fetal circulation into postnatal one. Few studies conducted in this area have shown association between NT-proBNP level and patency of ductus arteriosus and with respiratory distress syndrome of the newborn. Cardiac troponin T (cTnT)is a specific cardiac protein which serves as a specific indicator of cardiac damage in adults, it is usually not detected at birth but following myocardial injury its serum levels will slowly rise and generally will not be detectable until at least 4 hours after onset of injury. There is no "gold standard" test for diagnosis of hemodynamic instability in very low birth weight infants. Myocardial dysfunction is thought to be the major cause for this condition in VLBW population. Since this condition is associated with severe short and long term morbidity early recognition and specific treatment may be detrimental. We hypothesized that NT-proBNP and cTnT levels may serve as a more accurate markers for diagnosis, monitoring, and outcome prediction in VLBW infants during the first days of life, than the methods we currently use (blood pressure, urine output etc.)