Clotting and fibrinolytic disturbance during lung transplantation: Effect of low-dose aprotinin

Patients undergoing lung transplantation are often confronted,vith a bleeding problem that may be due in part to the use of cardiopulmonary bypass and its activation of blood clotting and fibrinolysis. Objective: We performed a prospective study to determine whether and to what extent the clotting and fibrinolytic systems are being activated and whether low-dose aprotinin is effective in inhibiting blood activation during lung transplantation. Methods: Thirty lung transplantations performed on 29 patients were divided into a group with cardiopulmonary bypass alone (n = 12), a group with cardiopulmonary bypass and 2 x 10(6) KIL aprotinin administered at the beginning of bypass in the pump prime (n = 12), and a group without cardiopulmonary bypass (n = 6), Serial blood samples were taken from the recipient before anesthesia, seven times during the operation, and 4 and 24 hours thereafter, Results: Results show that in the group having cardiopulmonary bypass alone, the concentration of the clotting marker thrombin/antithrombin III complex increased significantly during the early phase of the operation (p < 0.01) and remained high until the end of the operation, Levels of tissue-type plasminogen activator, a trigger of fibrinolysis released by injured endothelium, also increased sharply in the early phase of the operation in the cardiopulmonary bypass group (p < 0.01), followed by a significant increase in fibrin degradation products (p < 0.01), In the aprotinin group, a significant reduction of thrombin/antithrombin III complex (p < 0.05), tissue-type plasminogen activator (p < 0.05), and fibrin degradation products (p < 0.05) was observed in the early phase of the operation compared with levels in the bypass group, but these markers increased late during bypass associated with a significant drop (p < 0.05) of plasma aprotinin level monitored by plasmin inhibiting capacity, In the nonbypass group, concentrations of thrombin/antithrombin III complex and tissue-type plasminogen activator also rose significantly (p < 0.05) in the early phase of the operation, but the levels were significantly lower than those of the bypass group (p < 0.05), Blood loss during the operation was 2521 +/- 550 mi in the bypass group, 1991 +/- 408 mi in the aprotinin/bypass group, and 875 +/- 248 mi in the nonbypass group, Conclusion: These results suggest that clotting and fibrinolysis are activated during lung transplantation, especially in patients undergoing cardiopulmonary bypass. Aprotinin in a low dose significantly reduced activation of clotting and fibrinolysis in the early phase of the operation but not during the late phase of lung transplantation.