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We describe a case in which uncontrolled chronic disseminated intravascular coagulation (DIC) caused by an aortic aneurysm that was exacerbated by chemotherapy for lung cancer, showed dramatic improvement when warfarin, which was being administered for atrial fibrillation, was replaced by rivaroxaban, a direct oral anticoagulant (DOAC). The present case is interesting because a DOAC was effective in treating DIC due to an aortic aneurysm, whereas warfarin, another oral anticoagulant, was ineffective. In controlling DIC, it is important to inhibit activated coagulation factors such as thrombin and activated factor X, rather than the coagulation factors, which act as substrates.

Molecular makers such as thrombin-antithrombin complex (TAT), prothrombin fragment 1+2 (F1+2), soluble fibrin (SF), and D-dimer, are useful markers in the diagnosis and assessment of various thrombotic conditions. These markers are measured in plasma after blood sampling. Difficult blood sampling is known to falsely elevate plasma TAT levels. However, it is not known exactly why this occurs. In the present study, we examined how levels of molecular markers of haemostatic and fibrinolytic activation change under various sampling conditions using vacuum tube samples from healthy volunteers. When blood was sampled continuously by taking 10 consecutive vacuum tube samples following application of a tourniquet, blood sampling resulted in an accurate assessment of these molecular makers. When blood was sampled continuously by taking vacuum tube samples every one minute over a total of 9 minutes to investigate possible changes in the levels of the molecular markers over time, plasma levels of TAT, SF, and F1+2 gradually increased with time. Plasma levels of TAT, F1+2, and SF increased beyond the normal range over the course of nine minutes. When blood was sampled using three alternative methods, which varied in terms of the duration of needle puncture (sampling B), duration of tourniquet use (sampling C), or both (sampling A), plasma TAT and SF levels were significantly increased with all three methods, compared to control samples. Plasma F1+2 levels were significantly increased with sampling methods A and B, compared to control samples, but not with sampling method C. On the other hand, plasma D-dimer levels were not significantly altered by any of the sampling methods. In conclusion, the results suggest that molecular markers of haemostatic and fibrinolytic activation, except for D-dimer, may be affected by sampling method, particularly the duration of needle puncturing. Therefore, care needs to be taken when using TAT, F1+2, and SF levels to diagnose and estimate activation of the coagulation system.

Chronic disseminated intravascular coagulation (DIC) is a well-known complication of aortic aneurysm. A 63-year-old man with bleeding tendency and a large palpable abdominal aortic aneurysm (AAA) was diagnosed as having fibrinolysis dominant DIC by the excessive activation of both coagulation and fibrinolysis (plasmin -alpha2 plasmin inhibitor complex concentration is usually >4 microg/ml). Although several treatments were tried, DIC could not be controlled until the patient was given combined therapy of danaparoid (1,250 U/12 h, bolus IV) and tranexamic acid (0.5 g x 3/day, oral administration). This therapy may be beneficial when control for bleeding is required without restricting the ambulatory movement of patients by continuous drip.