Hemostasis alterations in patients with acute aortic dissection

Background: Surgery for acute aortic dissection (AAD) is frequently complicated by excessive postoperative bleeding and blood product transfusion. Blood flow through the nonendothelialized false lumen is a potential trigger for the activation of the hemostatic system; however, the physiopathology of the aortic dissection induced coagulopathy has never been precisely studied. The aim of the present study is the evaluation of the coagulation and fibrinolytic systems and platelet activation in patients undergoing surgery for AAD. Methods: Eighteen patients undergoing emergent surgery for Stanford type A AAD were enrolled in the study. The activation of the coagulation and fibrinolytic systems and platelet activation were evaluated at 6 different time points before, during, and after the operation, measuring prothrombin fragment 1.2 (F1.2), plasmin-antiplasmin complex, and platelet factor 4, respectively. Results: All measured biomarkers were increased before, during, and after the operations indicating a systemic activation of coagulation, fibrinolysis, and platelets. These changes were pronounced even preoperatively (T0), and soon after the beginning of cardiopulmonary bypass (T1) when the influence of hypothermia and prolonged cardiopulmonary bypass time were not yet involved. Time from symptom onset to intervention inversely correlated with preoperative F1.2 (r = -0.75; p = 0.002) and plasmin-antiplasmin levels (r = -0.57; p = 0.034). Conclusions: Blood flow through the false lumen is a powerful activator of the hemostatic system even before the operation. This remarkable activation may influence postoperative outcome of AAD patients. © 2011 The Society of Thoracic Surgeons.