Successful Management of DVT and PE in IVC-Agenesis and FVL Mutation with Direct Oral Anticoagulation (Factor Xa inhibitor): A Case Report

Abstract Background:Inferior vena cava (IVC) agenesis is a rare congenital condition identified as a primary cause of unprovoked deep vein thrombosis (DVT) in up to 5% of young men under 30. This case report is significant due to the rare co-occurrence of IVC agenesis and a heterozygous Factor V Leiden (FVL) mutation, contributing to extensive venous thromboembolisms (VTE). The literature has not previously documented cases with this specific combination treated with direct Factor Xa oral anticoagulation, adding to its novelty and clinical importance. Case Presentation: A 28-year-old obese Caucasian male presented with significant pain and swelling in his right lower extremity. Initial diagnostics included a venous Doppler ultrasound which revealed extensive right lower extremity DVT. Further CT scans of his chest and abdomen confirmed IVC agenesis and detected pulmonary emboli in his left central pulmonary arteries. Laboratory tests showed a positive result for heterozygous Factor V Leiden mutation. Treatment involved an intravenous heparin drip followed by a transition to direct Factor Xa oral anticoagulation. Conclusions: This case highlights the clinical complexity of treating patients with multiple risk factors for VTE and illustrates the potential for direct Factor Xa inhibitors as a successful long-term management strategy. It opens a discussion on the continuous use of direct Factor Xa oral anticoagulation in managing similar cases, which could influence future treatment protocols and provide a foundation for further research in this area.