Effect of Two Different Bypass Techniques on the Serum Troponin-T Levels in Newborns and Children

Abstract

Background— Cardiac troponin-T is a sensitive marker of myocardial damage. In a prospective study, the effect of 2 different pH strategies during cardiopulmonary bypass on ischemic myocardial injury and clinical outcome was measured in a pediatric population. Methods and Results— One hundred one patients (31 neonates 13.2±8.3 days and 70 children 34.5±44.1 months of age) undergoing open-heart surgery were selected to either α-stat (n=51) or pH-stat (n=50) acid-based management protocol. Serum troponin-T levels were measured before and 30 minutes after bypass and then 4 and 24 hours postoperatively. Surgical procedure, bypass details, inotropic support requirement, and postoperative recovery were recorded. Baseline troponin-T level was higher in neonates than in children (0.18±0.22 versus 0.04±0.05 μg/L, P =0.02). Also, a higher baseline level was found in patients with pulmonary hypertension (0.13±0.21 versus 0.04±0.05 μg/L, P =0.04). Cyanotic children showed a higher peak troponin-T level (3.76±3.11 versus 1.67±1.33 μg/L, P =0.04). Peak troponin levels showed a correlation with the length of circulatory arrest and aortic cross-clamp time. Postoperative levels remained high at 24 hours in patients requiring inotropic support. Peak troponin-T levels were significantly lower in the pH-stat group in patients with pulmonary hypertension ( P =0.03) and in cases where circulatory arrest ( P =0.01) or inotropic support ( P =0.01) was necessary during operation than in those with α-stat technique. Postoperative ventilation time and length of intensive care unit stay were also significantly longer with α-stat than with pH-stat technique ( P =0.005 and P =0.006, respectively). Conclusions— Cardiac troponin-T sensitively reflects myocardial damage in children. Our results suggest that pH-stat acid-based management protocol may provide better protection against ischemic myocardial damage than α-stat technique.