A systemic inflammatory reaction is known to occur in response to cardiopulmonary bypass (CPB). Recent data suggest leukocyte depletion after CPB may enhance myocardial function. To further investigate inflammation within the myocardium after CPB, northern blot analysis was performed for intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-α) on tissue obtained from dogs undergoing 90 mins of hypothermic CPB (26-28°C) with 60 mins of cardioplegic arrest. After rewarming, dogs were reperfused open chest for 3, 6 or 9 hrs at which time myocardial samples were obtained. Animals undergoing open thoracotomy without CPB served as time-matched controls. Data are summarized in the table below. Positive results for IL-6 and ICAM-1 were concordant in those animals tested for both. IL-6 is known to be important in the induction of myocyte ICAM-1 in other models. ICAM-1 may serve as an adhesion ligand for infiltrating leukocytes. The presence of IL-8 and TNF-α suggest activated infiltrating leukocytes within the myocardium. These preliminary data indicate that inflammation after cardiopulmonary bypass does involve the myocardium. We speculate this inflammatory response may contribute to depressed myocardial function postoperatively.
