Inferior Vena Cava Agenesis and Deep Vein Thrombosis: A Pharmacological Alternative to Vitamin K Antagonists

Inferior vena cava (IVC) agenesis is a rare congenital abnormality affecting the infrarenal segment, the suprarenal or the whole of the IVC. It has an estimated prevalence of up to 1% in the general population that can rise to 8.7% when abnormalities of the left renal vein are considered. Most IVC malformations are asymptomatic but may be associated with nonspecific symptoms or present as deep vein thrombosis (DVT). Up to 5% of young individuals under 30 years of age with unprovoked DVT are found to have this condition. Regarding the treatment of IVC agenesis-associated DVT, there are no standard guidelines. Treatment is directed towards preventing thrombosis or its recurrence. Low molecular weight heparin and oral anticoagulation medication, in particular vitamin K antagonists (VKAs) are the mainstay of therapy. Given the high risk of DVT recurrence in these patients, oral anticoagulation therapy is suggested to be pursued indefinitely. As far as we know, this is the first case reporting the use of a direct factor Xa inhibitor in IVC agenesis-associated DVT. Given VKA monitoring limitations, the use of a direct Xa inhibitor could be an alternative in young individuals with anatomical defects without thrombophilia, but further studies will be needed to confirm its efficacy and safety. LEARNING POINTS: Up to 5% of young individuals under 30 years of age with unprovoked deep vein thrombosis (DVT) are found to have this condition. Therefore, these types of anomalies should be actively looked for, particularly in young patients with DVT. Treatment with low molecular weight heparin or oral anticoagulation medication is the mainstay of therapy, directed towards preventing thrombosis or its recurrence. A direct factor Xa inhibitor could be a possible alternative to vitamin K antagonists in these patients, despite the lack of clinical evidence supporting its use at the moment.