Intravascular Ultrasound-Guided Iliofemoral Venous Stenting: In-Stent Mural Thrombus as a Possible Early Sign of Occult Malignancy.

Dedicated venous stents became available in Japan only recently, and reports of their use and follow-up in Japanese practice remain scarce. A 77-year-old woman developed acute left iliofemoral deep vein thrombosis (DVT) after prolonged recumbency and was treated with edoxaban. Eighteen days later she underwent endovascular therapy of the right lower limb for chronic limb-threatening ischaemia, and aspirin was added. Limb swelling and pain persisted despite three months of anticoagulation and graduated compression, and imaging then showed chronic occlusion of the left common and external iliac veins (EIV) with patent femoral and deep femoral inflow, corresponding to a favourable anatomical category of chronic venous obstruction (CVO). Under intravascular ultrasound (IVUS) guidance, which identified a stenotic distal landing zone in the proximal common femoral vein (CFV) that was not evident on venography, two Venovo venous stents (Becton, Dickinson and Company (BD), Tempe, AZ, USA) were deployed from the common iliac vein (CIV) to the CFV. Symptoms and clinical severity scores improved over the following months. Three months after stenting, duplex surveillance detected a localised mural thrombus along the posterior wall of the stent despite treatment with edoxaban and aspirin; the antiplatelet agent was changed to clopidogrel, yet the thrombus enlarged from 3 to 6 mm over the next six months before reaching a plateau. Nine months after stenting, an occult breast carcinoma was diagnosed incidentally. The stent remained patent at 12 months, through two bleeding events and three interruptions of antithrombotic therapy. This case illustrates one approach to managing an asymptomatic in-stent mural thrombus and raises the possibility that a thrombus forming despite adequate antithrombotic therapy may be an early manifestation of an undiagnosed malignancy.