Changes of fibrinolytic system in thrombolytic resuscitation of pulmonary thromboembolism-induced cardiac arrest model.

The objective of this study is to explore the changes in the coagulation and fibrinolysis system in an animal model with pulmonary embolism after cardiopulmonary bypass and to provide a theoretical basis for clinical practice. An animal model of cardiac arrest due to pulmonary embolism was established for venous thrombus (10-15 mL) in the left external jugular vein of 21 pigs. Computed tomography (CT) pulmonary arteriography was performed after the recovery of the underlying state, cardiac arrest state and spontaneous circulation, and then thrombolysis and cardiopulmonary resuscitation (recombinant tissue plasminogen activator [t-PA] 50 mg) were performed immediately. The changes of tissue factor (TF), tissue factor pathway inhibitor (TFPI), t-PA and plasminogen activator inhibitor-1 (PAI-1) in the blood were detected by ELISA. The blood samples were collected immediately, 1, 2, 4 and 6 hours after the recovery of spontaneous circulation. Data from animals that were successfully resuscitated at different time points were compared using a repeated measures one-way analysis of variance. Seventeen pigs had cardiac arrest after 10 to 15 mL of thrombus injection, and the other four had cardiac arrest after 5 to 8 mL of additional thrombus. Nine pigs survived 6 hours of cardiopulmonary resuscitation. CT pulmonary angiogram showed pulmonary artery obstruction. TF levels were increased compared with basal status, but there was no statistical difference (P > .05). TFPI levels were higher at 1, 2, 4 and 6 hours after recovery of spontaneous circulation compared with basal state (P < .05); t-PA levels were higher at cardiac arrest, and immediately after recovery of spontaneous circulation compared with basal state. There was a statistical difference in PAI-1 level at 1, 2, 4 and 6 hours after recovery of spontaneous circulation (P < .05). There was no statistical difference in PAI-1 level at each stage compared with basal state (P > .05). TFPI has a certain influence on the coagulation and thrombosis regulation of the body, and the increase in fibrinolytic activity has a positive promoting effect on the thrombolysis. It provided the theoretical basis of clinical treatment of thrombotic diseases.