Summary
Cardiopulmonary bypass (CPB) is associated with impaired platelet function and a systemic
inflammatory response. The present study was designed to evaluate whether any correlation
between platelet activation and inflammatory response during CPB exists. The results
obtained from 8 patients undergoing hypothermic CPB for cardiac surgery showed the
occurrence of a moderate degree of platelet activation during CPB, demonstrated by
an increase of platelet CD62P expression in correlation with an increase of β-thromboglobulin
levels, with a concomitant decrease of in vitro platelet response. Plasma IL-1β levels significantly increased during CPB, with a
peak between 1 and 4 h after CPB. Similarly, IL-6 levels were elevated 30 min from
CPB starting, peaked at 4 h, and remained elevated after 24 h. A direct correlation
was found between plasma IL-1β and IL-6 levels. A significant correlation between
plasma IL-1β and β-thromboglobulin levels was also found. In turn, plasma β-thromboglobulin
levels correlated with CD62P expression on activated platelets. An inverse correlation
was found between in vitro platelet aggregation and plasma IL-1β or IL-6 levels. From the present results it
may be speculated that platelet activation during CPB may contribute, through the
release of IL-1β, to activation of endothelial cells and subsequent release of other
cytokines with chemotactic and pro-inflammatory properties, thus playing an important
role in the inflammatory response associated with CPB.