Plenary Session
AB095. SOH26AB_0128. The impact of bariatric surgery on the pharmacokinetics of direct oral anticoagulants: a multicentre Irish cohort study
Czara Kennedy1, Emile Esim-Enoh2, Aaron Thomas2, Susan Healy3, Nicola O. Toole3, Katherine Egan1, Aimee Brennan1, Jessica Maddock1, Karen Murphy4, Paul Cromwell1, Chris Collins1, William Robb3, Waqas Butt5, Donal O’Shea1, Naomi Fearon1, Helen Heneghan1
1Department of Bariatric and Upper GI Surgery, St. Vincent’s University Hospital, Dublin, Ireland;
2School of Medicine, University College Dublin, Dublin, Ireland;
3Blackrock Weight Care, Blackrock Clinic, Blackrock, Ireland;
4Department of Coagulation, St. Vincent’s University Hospital, Dublin, Ireland;
5Department of Endocrinology, St. Vincent’s University Hospital, Dublin, Ireland
Background: The use of direct oral anticoagulants (DOACs) after bariatric surgery remains controversial due to potential alterations in drug absorption following procedures such as sleeve gastrectomy and Roux-en-Y gastric bypass. Current evidence is limited, with inconsistent pharmacokinetic (PK) data and uncertainty regarding the reliability of individual agents. The aim of this study was to determine the impact of bariatric surgery on the PKs of DOACs.
Methods: We conducted a multicentre observational cohort study across three Irish bariatric centres, identifying all patients who had undergone bariatric surgery and were subsequently prescribed any DOAC for indications such as venous thromboembolism or atrial fibrillation. These patients were identified through an institutional audit process and invited to participate, with full ethical approval obtained prior to recruitment. Peak plasma DOAC concentrations were measured using drug-specific calibrated anti-Xa assays or liquid chromatography-mass spectrometry (LC-MS)/MS, according to local laboratory protocols. Expected therapeutic ranges were defined using established phase II/III PK reference values, and clinical events were recorded descriptively.
Results: A total of 50 patients have been recruited, including individuals who have undergone sleeve gastrectomy and Roux-en-Y gastric bypass. Preliminary analysis indicates that apixaban demonstrates more reliable postoperative absorption, whereas rivaroxaban levels appear more variable and, in several cases, fall below anticipated therapeutic peaks. Further clinical outcomes and comprehensive PK evaluation are ongoing, and full results will be presented at the meeting.
Conclusions: This multicentre Irish study represents the largest series to date evaluating DOAC use following bariatric surgery. Findings demonstrate a clear difference in postoperative absorption patterns, with apixaban showing more reliable therapeutic levels and rivaroxaban displaying consistently reduced exposure. These results support cautious preferential use of apixaban in this cohort. A prospective clinical trial is currently underway to further characterise PK and pharmacodynamic behaviour post-surgery and to inform evidence-based anticoagulation strategies in patients with obesity post-bariatric surgery.
Keywords: Anti-Xa levels; bariatric surgery; direct oral anticoagulants (DOACs); drug absorption; obesity
Acknowledgments
None.
Funding: None.
Conflicts of Interest: The authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
doi: 10.21037/map-26-ab095
Cite this abstract as: Kennedy C, Esim-Enoh E, Thomas A, Healy S, Toole NO, Egan K, Brennan A, Maddock J, Murphy K, Cromwell P, Collins C, Robb W, Butt W, O’Shea D, Fearon N, Heneghan H. AB095. SOH26AB_0128. The impact of bariatric surgery on the pharmacokinetics of direct oral anticoagulants: a multicentre Irish cohort study. Mesentery Peritoneum 2026;10:AB095.
