Release of Lipopolysaccharide Toxicity-Modulating Proteins in Patients Undergoing Cardiopulmonary Bypass Using Noncoated and Heparin-Coated Extracorporeal Circuits: A Clinical Pilot Study

Abstract

Cardiopulmonary bypass (CPB) induces a generalized inflammatory response, including activation of leukocytes, contributing to postoperative morbidity. The inflammatory pathways leading to this systemic inflammatory response syndrome are considered identical to those involved in septic shock. Therefore, we studied the release of bactericidal/permeability-increasing protein (BPI), lipopolysaccharide binding protein (LBP), and soluble CD14 (sCD14)-all proteins that modulate the effects of lipopolysaccharide (LPS)-in patients undergoing CPB. In addition, the effect of heparin coating of the extracorporeal bypass circuit on the release of these parameters was assessed. Prospective, randomized clinical pilot study. Cardiothoracic Surgery Department in a university hospital. Fourteen patients undergoing elective coronary artery bypass grafting were included. Seven patients underwent CPB using a standard, noncoated extracorporeal circuit, and seven patients had CPB using a heparin-coated extracorporeal circuit (Duraflo II). Blood samples were taken after induction of anesthesia, just before aortic crossclamping, and 0, 0.5, 1.5, 3, 6, 12, and 24 h after declamping. CPB with a noncoated extracorporeal circuit induced a sharp increase in neutrophil-derived BPI, manifest directly after release of the aortic crossclamp, which was significantly attenuated using a heparin-coated system. Also, CPB induced a gradual increase of the acute-phase reactant LBP, which was identical in the noncoated and heparin-coated groups. Systemic release of sCD14 after crossclamp release was significantly higher in the noncoated group compared with the heparin-coated group, but did not rise above baseline levels. These data confirm that CPB-induced leukocyte activation is attenuated using a heparin-treated extracorporeal circuit and point to the possible role of LPS toxicity-modulating proteins in the systemic inflammatory response after bypass surgery.