Reduction of the inflammatory response following coronary bypass grafting with total minimal extracorporeal circulation

Objective: Cardiopulmonary bypass (CPB) is known to cause part of the systemic inflammatory reaction after cardiac surgery that can be responsible for organ failure. A novel technique based on a minimal extracorporeal circulation (MECC) system has been evaluated with regard to the inflammatory response in a prospective study involving patients undergoing coronary artery bypass grafting. Methods: Sixty consecutive patients were randomly assigned to either standard normothermic CPB (n = 30) or the MECC system, with a reduced priming volume, no aortic venting and no venous reservoir, excluding the blood-air interface (n = 30). Specific evaluation of cytokine release (IL-1beta, IL-6, TNF-alpha), as well as neutrophil elastase secretion and beta-thromboglobulin release from platelets and S100 protein assay were performed. Serial blood samples were taken prior to the onset, after initiation, at the end and after weaning of the CPB; further samples were collected 6 and 24 h after the end of the CPB. Results: All patients were similar with regards to pre- and intra-operative characteristics and clinical outcomes were comparable for both groups. MECC system allowed a reduced hemodilution with a mean drop of the hematocrit of 8.5 vs. 15.3% (P < 0.05). Mononuclear phagocytes dropped in a more important manner under standard CPB conditions (247 +/- 151 vs. 419 +/- 168, P = 0.002), but both groups demonstrated a rise in monocyte count at the end of the CBP. No significant release of IL-1beta was observed in either group. By the end of CPB, IL-6 levels were significantly lower in the MECC group (38.8 +/- 19.6 vs. 87.9 +/- 78.9, P = 0.04), despite a higher monocyte count. Plasma levels of TNF-alpha rised significantly more during standard CPB than with the MECC system (17.8 +/- 15.4 vs. 10.1 +/- 5.6, P = 0.002). With MECC, the neutrophil elastase release was reduced (72.7 +/- 47.9 vs. 219.6 +/- 103.4, P = 0.001). Platelet count remained at higher values with the minimal compared to standard CPB. It is noteworthy to consider that beta-thromboglobulin levels showed slightly lower platelet activation in the MECC group at all times of CPB (110.5 +/- 55.6 vs. 134.7 +/- 46.8, P = 0.10). The pattern of release of S 100 protein showed higher values in patients undergoing standard CPB than after MECC. Conclusions: The MECC system is suitable to maintain total extracorporeal circulation and demonstrates a lower inflammatory reaction when compared to standard CPB. (C) 2002 Elsevier Science B.V. All rights reserved.