Background: Perioperative myocardial injury is determined by the ischemic duration, pathology, and preoperative myocardial status. Our aim was to evaluate pathology-related differences in troponin I (TnI) release, a sensitive and specific marker of myocardial injury, and its relation to clinical outcome after pediatric open heart surgery.
Methods: Troponin I was measured serially postoperatively in 133 children undergoing repair of atrial (ASD, n = 41) and ventricular septal defects (VSD, n = 46), and tetralogy of Fallot (TOF, n = 46). The length of the right ventricular outflow tract (RVOT) incision in the latter was classified as either minimum(n = 33) or extended(n = 13).
Results: Postoperative TnI levels were lesion specific and did not correlate with clinical outcome for ASDs. Peak TnI correlated with inotropic duration for VSD (r = 0.69, p < 0.0001) and TOF (r = 0.51, p = 0.0004). Significant correlations were also observed for the durations of ventilation (r = 0.64 and 0.36, respectively) and ICU stay (r = 0.60 and 0.55). Younger age (<1 year old) in children with VSDs and an extended incision into the RVOT in TOF were associated with greater TnI release and worse clinical outcome.
Conclusions: Postoperative TnI release is pathology related and reflects myocardial damage from both ischemia-reperfusion injury and direct myocardial trauma.