[A case of deep vein thrombosis in an elderly patient whose symptoms were exacerbated after applying catheter-based thrombolytic therapy].

We herein report a 99-year-old woman with hypertension and dyslipidemia. From the beginning of August 20XX, significant edema from the left thigh to the toes had been observed, so she had consulted her previous doctor. She had been suspected of having cellulitis and was given antibiotics, but no improvement in her symptoms was noted, so she was transferred to our hospital. The edema of the lower leg was localized to the left lower leg only, and the D-dimer level was as high as 16.6 μg/mL at her visit to the emergency room, so deep vein thrombosis (DVT) was suspected, and the patient received immediate hospitalization. Continuous administration of undifferentiated heparin was started, and lower extremity venous ultrasound was performed. As a result, central-type DVT extending from the left iliac vein to the common iliac vein bifurcation was observed. However, despite administering inferior vena cava (IVC) filter into under the renal vein, and changing heparin to edoxaban 30 mg, no improvement in the lower limb edema was observed. Therefore, catheter-based thrombolysis (CDT) was started on day 11 of illness, and continuous administration of urokinase was started via the catheter. Heparin and edoxaban were not used in combination in order to reduce the risk of bleeding. The edema gradually improved, and after confirming that the thrombus had completely disappeared on lower extremity venous ultrasound, the catheter was removed on day 14 (day 24 of illness) after starting CDT. The IVC filter was also removed, and prescription of edoxaban 30 mg was restarted. Since the patient had used a walking frame at home, she started rehabilitation from the initiation of CDT therapy and was discharged once she was able to use a self-sustaining portable toilet. The basic treatment for DVT is anticoagulant therapy; however, a large amount of thrombosis was observed in the present case, and no marked improvement was observed with conventional anticoagulant therapy. As the patient was particularly elderly, and considering that it was important to improve the edema promptly in order to maintain her activities of daily living, we performed CDT treatment and concluded that it was very effective in this case. However, the CDT procedure for DVT has yet to be standardized, and there are few cases of CDT treatment, especially for such super-elderly patients. In the current aging society, the incidence of DVT diseases is increasing, and in cases such as the present case, anticoagulation therapy alone and CDT therapy should be considered and implemented after careful consideration of the bleeding risk.