Patterns and prognostic value of troponin, interleukin-6, and leptin after pediatric open-heart surgery

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 μg/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 μg/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.