Release of S100B during coronary artery bypass grafting is reduced by off-pump surgery.

Background: S100B, a plasma marker of brain injury, was compared after coronary artery bypass grafting with and without cardiopulmonary bypass (CPB).
Methods: Fourteen patients with off-pump operations and 18 patients with CPB were compared. Seven patients in the off-pump group underwent a minithoracotomy and received only an arterial graft, whereas 7 patients underwent sternotomy and received both an arterial and one or two vein grafts. S100B was measured in arterial plasma using an immunoassay with enhanced sensitivity.
Results: S100B before the operation was 0.03 microg/L. At wound closure, S100B in patients of the off-pump and CPB groups reached a maximum level of 0.22 +/- 0.07 and 2.4 +/- 1.5 microg/L, respectively (p < 0.001). No strokes occurred. Patients without CPB receiving arterial and vein grafts released slightly more S100B (p < 0.05) than patients with only arterial grafting. In patients undergoing CPB, S100B increased slightly before aortic cannulation (p < 0.001), to the same level as the maximum reached for the non-CPB group.
Conclusions: Coronary artery bypass grafting with CPB caused a 10-fold greater increase in S100B than off-pump grafting. S100B release after off-pump sternotomy with vein grafting was slightly greater than in arterial grafting through a minithoracotomy.