Duplication of inferior vena cava and coagulation mutations with left-sided iliofemoral venous thrombosis.

Duplication of the inferior vena cava (IVC) with coagulation mutations in the form of factor V Leiden and MTHFR mutations represents an unusual subset of patients. We are reporting a case of a 43-year-old man who presented with left iliofemoral deep venous thrombosis diagnosed on duplex ultrasound scan. At the time of catheter-directed thrombolysis with prophylactic IVC filter placement, a duplicated IVC system was observed. After thrombolysis, a stenotic lesion in the left common iliac vein and IVC was stented. IVC filters were retrieved after 6 weeks. On thrombophilia profile testing at 3 months, he was also found to have factor V Leiden and MTHFR mutations. After 12 months of follow-up, the patient is asymptomatic with a patent iliocaval venous system and is receiving lifelong anticoagulation.