Aortic aneurysms associated with DIC are occasionally encountered, but are rarely symptomatic. Only approximately 0.5%–1.0% of aortic aneurysms present a bleeding tendency due to aneurysm-related DIC [1].

Activated coagulation is observed in DIC. However, the degree of fibrinolytic activation depends on the disease type [2]. DIC can be classified as suppressed fibrinolytic, balanced fibrinolytic, or enhanced fibrinolytic [2].

Unlike suppressed fibrinolytic DIC caused by infections such as sepsis, DIC associated with aortic aneurysms characterized by fibrinolysis is markedly enhanced, and bleeding is more common [2].

The preoperative TAT, FDP, and D-dimer values measured in this patient were all elevated (TAT 35.8 ng/ml, FDP 47.5 µg/ml, D-dimer 36.5 µg/ml). In addition, when bleeding symptoms were recognized but when organ symptoms were not, the patient’s FDP was elevated more than D-dimer was. Due to the only one preoperative blood test and lack of PIC measurements, it was not clear if the patient strictly met the criteria for an enhanced fibrinolytic type of fibrosis [2]. However, it was presumed that this patient had DIC that was classified as either the balanced fibrinolytic type or the enhanced fibrinolytic type.

Treatment for DIC consists of treating the underlying disease. However, treatment strategies for AAAs presenting with DIC are unclear, as there is still no high-level evidence [3].

Considering the patient's advanced age and the fact that she and her family requested a less invasive treatment, we proposed EVAR. We decided to go ahead with surgery because her general condition was stable. On postoperative day 1, the DIC score worsened to 6 and it was determined that any medical treatment should be added. Nafamostat mesylate has antiplasmin activity in addition to antithrombin activity and there is less concern about side effects that may contribute to bleeding tendency. Additionally, many reports have described successful treatment in patients with aortic aneurysms [3]. On postoperative day 3, the patient weaned off DIC with a score of 2, and Nafamostat mesylate was discontinued.

There are several reports of the use of recombinant human soluble thrombomodulin as an anticoagulant therapy for controlling DIC with AAA [4, 5]. However, there is little reported experience in administering this drug to DIC patients with underlying diseases other than hematopoietic malignancies, infections, or solid tumors, and its efficacy and safety have not been established for the treatment of aortic aneurysms. The pharmacological mechanism of this drug in treating AAA is also unknown.

In particular, there are a few established options and no clear strategies regarding other medical therapies, such as anticoagulation (unfractionated heparin, heparin, direct oral anticoagulation), replacement therapy (fresh frozen plasma, platelet concentrates) and antifibrinolytic therapy (tranexamic acid), and the optimal timing of treatment for DIC associated with aortic aneurysm is also unknown.

Treatment with EVAR followed by the use of Nafamostat mesylate in the early postoperative period enabled the quick resolution of the patient’s DIC and improvement of the symptomatic bleeding tendency. However, further research is needed on the optimal timing of the use of Nafamostat mesylate, specifically whether this drug should be administered preoperatively or postoperatively.

DIC can be caused by endoleak alone at any time during EVAR or after the procedure. Because the neck from the renal arteries was short and highly curved, there was concern that type I endoleak would occur. Initially, we planned to extend the neck length by placing stent grafts in both renal arteries and then placing the stent grafts. As a result, a stent graft was placed without placing stent grafts in the renal arteries due to the difficulty of the procedure, and fortunately, no type I endoleak was observed. To prevent type I endoleaks, we selected the Endurant stent graft system, which has greater flexibility due to the use of wire-shaped M-shaped stents and suprarenal active fixation by a suprarenal stent.

Inferior mesenteric artery patency (IMA) with an IMA ≥ 3.0 mm and lumbar artery length of ≥ 2.0 mm are reported to be independent risk factors type II endoleak [6]. Preoperative CT images of this patient showed that the IMA was patent but had a diameter of 1 mm, and none of the lumbar arteries were larger than 2 mm; therefore, preoperative coil embolization to prevent type II endoleak was considered unnecessary. Even if there is no problem in the short term, it is necessary to carefully follow up on the presence or absence of endoleak using contrast-enhanced CT during a long-term follow-up.

Our research has certain limitations. Although PIC and α2PI values were missing in this study, they are important markers for analyzing the pathology of DIC in detail. Furthermore, the presence or absence of α2PI deficiency may predict the amount of intraoperative bleeding.