Effects of Artificial Lung and Roller Pump on Platelet Morphology and Activation During Simulated Extracorporeal...

Prolonged extracorporeal circulation time is known to cause intraoperative and postoperative bleeding, but the underlying mechanism is not fully understood. In this study, we analyzed the effects of artificial lung and roller pump on platelet morphology and activation using a simulated extracorporeal circulatory circuit.

Blood was drawn from healthy volunteers in the presence of unfractionated heparin as an anticoagulant and recirculated for 180 min at 0.75 L/min with the circuit under a room temperature. After the samples were collected, platelet counts, platelet surface markers, and platelet activation markers were measured.

When whole blood was circulated for 180 min, platelet counts, platelet sizes, and expressions of glycoprotein Ibα (CD42b) and glycoprotein IIb (CD41) significantly decreased after recirculation. In addition, dense bodies and α-granules within platelets were also reduced after recirculation. Adhesion to collagen and platelet aggregation were significantly reduced after recirculation compared to pro-circulation. When platelets were stimulated with A23187 pro- and post-extracorporeal circulation, the expression of P-selectin was significantly lower in CD42b^- platelets than in CD42b⁺ platelets. On the other hand, phosphatidylserine (PS) exposure in CD42b^- platelets was higher than in CD42b⁺ platelets with or without stimulation.

It was suggested that artificial lungs and roller pumps may reduce platelet activity by causing cleavage of platelet membrane glycoproteins and release of granules within platelets.