ABSTRACT
PURPOSE: Leptin and interleukin-6 (IL-6) are inversely correlated and associated with decreased survival in critically ill patients. We investigated changes in leptin, IL-6, and troponin in children undergoing open-heart surgery, hypothesizing that IL-6 and troponin will increase after cardiopulmonary bypass (CPB) and will be negatively correlated with leptin. PATIENTS AND METHODS: Serial blood samples were collected from 21 patients 24 hours before and up to 48 hours after surgery. RESULTS: Leptin levels decreased by 50% during CPB (P < .001), then gradually increased, reaching baseline levels 12 hours after surgery. The IL-6 levels increased (P < .001) during CPB, peaking 2 hours after surgery and remaining slightly elevated at 24 hours after surgery (P < .001). Leptin and IL-6 were negatively correlated (R = -0.448, P < .001). Troponin levels increased during CPB (P < .001). Postoperative leptin and troponin were inversely correlated (r = -0.535, P < .001). Patients with modest elevations in troponin levels (<20 microg/L) had a shorter aortic clamp and CPB time (P < .01), lower IL-6 peak levels (P = .03), and shorter duration of ventilation and inotropic support compared with patients with peak troponin levels greater than 20 microg/L. CONCLUSIONS: Lower leptin and higher IL-6 levels correlated with troponin, a marker of myocardial injury. Because leptin may have cardioprotective effects, the postoperative drop in its levels may further contribute to myocardial dysfunction.
