Negative Reexploration for Cardiac Postoperative Bleeding: Can It Be Therapeutic?

Background. Reexploration of the mediastinum for bleeding is required in 3% to 7% of patients after cardiac operation, with many proving to have no surgically correctable cause. In spite of a “negative exploration,” the bleeding often ceases. We propose the hypothesis that such a negative exploration can be therapeutic by reducing marked fibrinolytic activity in the mediastinal cavity. Methods. Fibrinolytic activity in shed mediastinal blood was compared with that in the system blood in 5 patients after cardiac operation by measuring fibrinogen, fibrin degradation product, plasminogen activator inhibitor-1, and α2-antiplasmin levels. Results. Fibrinolytic activity in mediastinal blood was markedly increased when compared with paired systemic venous blood. This was indicated by the mediastinal blood’s lower fibrinogen levels (0.47 versus 1.91 U/mL; p < 0.001), very high levels of fibrin degradation products (1,350 versus 200 ng/mL; p < 0.05), and higher levels of plasminogen activator inhibitor-1 (55.5 versus 28.1 ng/mL; p < 0.005). Decreased levels of α2-antiplasmin were also observed in the mediastinum (0.50 versus 0.61 U/mL; p < 0.05). Conclusions. Our data confirm that fibrinolytic activity can be extremely high in the mediastinum in response to clot formation. This may explain the hemostatic effects of a negative reexploration, where irrigation and the removal of clots may reduce the fibrinolytic process; this may allow the bleeding ends of capillaries and small vessels to thrombose. Decreased levels of α2-antiplasmin observed suggest that lysine analogs, such as ε-aminocaproic acid, may have a beneficial role when locally delivered into the mediastinum.