Summary. Background: The peri-operative management of patients on oral anticoagulants (OACs) is a common clinical problem. Our aim was to determine the incidence of major bleeding during peri-operative administration of treatment-dose enoxaparin and the impact of the extensiveness of the procedure on the risk of bleeding.
Methods: We performed a prospective cohort study of 260 patients at 24 North American sites on OACs for atrial fibrillation or a history of deep vein thrombosis (DVT) requiring invasive or surgical procedures whose treating physician felt that bridging therapy was required. Warfarin was withheld, and once-daily s.c. enoxaparin (1.5 mg kg−1) was given peri-operatively. Patients were followed for 28 days after OAC was therapeutic.
Results: Major bleeding was observed in nine of 260 patients (3.5%, 95% CI: 1.6–6.5). The bleeding risk varied markedly by extensiveness of procedure: the incidence of major bleeding for invasive procedures, minor surgery and major surgery was 0.7% (95% CI: 0.02–3.7), 0% (95% CI: 0–5.0), and 20.0% (95% CI: 9.1–35.7), respectively. There were five thromboembolic events in total (1.9%, 95% CI: 0.6–4.4). There were four arterial events (2.3%, 95% CI: 0.6–5.7) in 176 patients with atrial fibrillation, and one venous event (1.0%, 95% CI: 0.03–5.7) in 96 patients with prior DVT.
Conclusions: Bridging therapy with once-daily therapeutic-dose enoxaparin administered primarily in an outpatient setting has a low incidence of major bleeding for patients undergoing invasive procedures and minor surgery. Further studies are needed to optimize the bridging strategy for patients undergoing major surgery.