Absorption and anticoagulant management of rivaroxaban in patients with short bowel syndrome

Background: Patients with short bowel syndrome (SBS) often rely on parenteral nutrition via central venous catheters, increasing the risk of thrombosis. Many also require long-term anticoagulation due to other conditions. While warfarin was traditionally preferred, direct oral anticoagulants like rivaroxaban are now more common. However, no larger studies have assessed rivaroxaban absorption in SBS patients. Aim: The aim of this study was to do a further characterization of the absorption of rivaroxaban in patients with SBS. The secondary aim was to assess thromboses and bleeding events in patients on continuous treatment with rivaroxaban. Methods: A retrospective, five-year cohort study following a 20 mg dose rivaroxaban, plasma concentrations were measured at 1.5, 2.5, and 3.5 h, in 34 patients with SBS. Thrombotic and bleeding events and clinical data were sought in medical records. Patients were characterized with the length of the small intestine and the weekly volume of intravenous fluid support. Results: The Cmax of rivaroxaban correlated positively with intestinal length (p = 0.005) and negatively with the weekly total fluid support (p = 0.0001). A cut-off value regarding intestinal length and adequate absorption was estimated between 125 and 150 cm. In a cumulative follow up time of 19.6 years, one event of thrombosis and one event of bleeding was observed. Conclusion: Rivaroxaban absorption correlates with intestinal length and functionality. Anticipating few thrombotic and bleeding events during treatment, rivaroxaban seemed efficient and safe, but further studies are warranted to clarify its role in SBS patients.