N-acetyl-B-D-glucosaminidase and inflammatory response after cardiopulmonary bypass.

OBJECTIVE To determine the changes in activity of plasma N-acetyl-beta-D-glucosaminidase, a marker for inflammation as well as renal, pulmonary and cardiac damage and proinflammatory cytokines in patients undergoing coronary artery bypass grafting and find out the relationship between their plasma levels with clinical outcome of patients. STUDY DESIGN Cross-sectional study. PLACE AND DURATION OF STUDY The Aga Khan University, Karachi, from January to June 2003. PATIENTS AND METHODS N-acetyl-beta-D-glucosaminidase (NAG) activity and concentrations of tumor necrosis factor-alpha of (TNFalpha), interleukin 6 (IL-6), interleukin 8 (IL8) and granulocyte-macrophage colony stimulating factor (GM-CSF) were monitored in plasma samples of 12 angina patients undergoing coronary artery bypass grafting (CABG), before, immediately after and 5 days post-surgical procedure. Serum glucose concentrations were also monitored in those patients. Patient's clinical condition was monitored during this time period. RESULTS No significant increase was observed in plasma NAG activity (a marker of inflammation) or in plasma levels of TNFalpha, IL-6, IL-8 and GM-CSF immediately after surgery, indicating that cardiopulmonary bypass itself does not produce any significant amount of inflammation immediately after CABG. However, 5 days post surgery, there was a significant increase in plasma NAG activity (p=0.001), TNFalpha (p=0.047) and GM-CSF (p=0.045). There was no relationship between plasma NAG activity and clinical outcome because various parameters of renal, cardiac and pulmonary functions, though slightly affected, remained within the normal limits. CONCLUSION Increased levels of NAG and TNFalpha did not affect clinical outcome. However, data suggest that NAG can be a potential marker for inflammation and end organ damage following CABG. An increase in GM-CSF on day 5 following CABG indicates enhanced body's defense mechanism against infection.