Platelet and neutrophil activation during cardiac surgical procedures: Impact of cardiopulmonary bypass

Background. Platelet and neutrophil activation plays a crucial role in reperfusion injury. To determine whether platelet and neutrophil activation occurs in the coronary circulation after cold cardioplegic arrest and reperfusion, we studied 22 patients undergoing coronary artery bypass or valve procedures, or both procedures. Methods. Blood was sampled from the coronary sinus and the radial artery (A) before bypass; (B) immediately after cross-clamp release; and (C) 5 minutes after crossclamp release; and was analyzed for surface markers of platelet (CD62P) and neutrophil (CD11b) activation. Results. During bypass, platelet activation increased significantly (p < 0.01) over prebypass values, but no difference was seen between arterial and coronary sinus samples. Neutrophil activation also increased significantly (p < 0.001) during bypass, but there was no difference between arterial and coronary sinus samples. Conclusions. Cellular activation occurs locally in the coronary circulation during bypass, but no more so after cold cardioplegic arrest and reperfusion.