An Activated State of Blood Coagulation and Fibrinolysis in Patients with Abdominal Aortic Aneurysm

Background: Relationships between blood coagulation and the fibrinolysis system and morphology of aneurysms in patients with abdominal aortic aneurysm (AAA) are unknown. Methods: Preoperative and postoperative evaluations of hemostatic factors such as thrombin-antithrombin III complex (TAT), D-dimer, fibrinogen/fibrin degradation products (FDP), and platelet count were performed in 36 patients with atherosclerotic AAA. As control subjects, 25 age- and sex-matched healthy volunteers were analyzed for these hemostatic factors. In all patients, morphological evaluation of AAA included the largest diameter, tortuosity, and the thickness of intraluminal thrombus to be compared with preoperative levels of hemostatic factors such as alpha-2 plasmin inhibitor-plasmin complex (PIC), thrombomodulin (TM), von Willebrand factor (vWF), tissue factor (TF), and free form of tissue factor pathway inhibitor (F-TFPI). Results: The preoperative values of TAT, D-dimer, and FDP were significantly higher in AAA patients than in controls. Of all patients, 23 (64%) or 22 (58%) had TAT or D-dimer values greater than 8.2 ng/mL or 3.4 μg/mL (mean + 2SD of controls), respectively. The postoperative values of these hemostatic factors significantly improved, but were not normalized. The largest diameter of AAA correlated with the preoperative levels of TAT (r = 0.566, P = 0.001), D-dimer (r = 0.644, P = 0.0001), FDP (r = 0.561, P = 0.0009), PIC (r = 0.413, P = 0.0146), and F-TFPI (r = 0.408, P = 0.0158). We have also found that tortuosity of AAA has relation not only to the preoperative levels of fibrinolytic factors but also to the plasma F-TFPI antigen levels. On the other hand, the preoperative levels of a marker of endothelial damage, such as TM or vWF, and TF did not correlate with those of F-TFPI in all patients. The maximum thickness of thrombus in AAA significantly correlated not only with the preoperative levels of TAT, D-dimer, FDP, and PIC, but also with AAA size. Conclusions: We have found evidence that an activated state of both blood coagulation and fibrinolysis in AAA patients is associated with the morphological characteristics of aneurysms.