S4896 Upper Extremity Deep Vein Thromboses in a Young Man with Fistulizing Crohn’s Disease: A Case of Anticoagulant Failure

Introduction: Patients with Inflammatory Bowel Disease (IBD) face a significantly increased risk of thromboembolic events, particularly during active flares, with rates up to 3 times higher than the general population. As IBD prevalence rises, effective venous thromboembolism management has become increasingly important. Direct oral anticoagulants (DOACs) are recommended for long-term anticoagulation in non-cancer patients; however, their efficacy in Crohn’s disease remains uncertain due to potential absorption issues related to active inflammation or altered gastrointestinal anatomy. Case Description/Methods: A 24-year-old man with fistulizing Crohn’s disease presented with acute left arm pain and swelling following exertional activity. His history included multiple fistulas and a prior ileocolonic resection with seton placement. He had been on infliximab, discontinued due to insurance issues. He denied recent immobilization, steroid use, intravenous drug use, or travel. Doppler ultrasound showed an acute subclavian vein deep vein thromboses, and he was discharged on apixaban. Three days later, he returned with pain and temperature changes in the left hand. Imaging revealed thrombus extension into the axillary and subclavian veins. He underwent AngioJet™ thrombectomy with catheter-directed tPA. Due to thrombus progression despite DOAC therapy, hematology recommended warfarin, citing concerns about impaired absorption from Crohn’s disease and prior resection. The patient declined due to anticipated difficulty with INR monitoring and was transitioned to low-molecular-weight heparin. Discussion: This case highlights a key limitation of DOAC use in Crohn’s disease with prior ileocolonic resection. Apixaban, a direct factor Xa inhibitor, is primarily absorbed in the distal small intestine and ascending colon and may be ineffective in patients with active inflammation or those who have undergone surgical resection of these regions. In this patient, known involvement of the terminal ileum and cecum, along with prior resection, likely led to impaired absorption and inadequate anticoagulation, resulting in thrombus progression. Warfarin, with systemic metabolism and INR monitoring, offers a more reliable alternative in such settings. Active Crohn’s disease can further impair absorption of oral medications, and in advanced cases, hypoalbuminemia may alter drug pharmacokinetics. This case underscores the need for individualized anticoagulation strategies in IBD, with careful consideration of disease activity, anatomy, and drug efficacy.