Apixaban in Abdominal Transplantation: An Antithrombotic Stewardship Assessment.

BACKGROUND: Apixaban is a direct oral anticoagulant (DOAC) that is widely used in the general population; however, its use in solid organ transplant (SOT) recipients has not been extensively studied. Although there is interest in DOACs as the preferred oral anticoagulants in SOT recipients due to their favorable pharmacokinetic properties, there remain concerns for the optimal dose in the setting of organ dysfunction, at the time of engraftment, and for use for off-label indications such as graft thrombosis (GT). OBJECTIVE: To assess "real-world" apixaban utilization in abdominal SOT recipients at a large academic medical center. DESIGN: This was a single-center, observational, retrospective cohort study of 79 adult patients from January 2020 to August 2022 who received apixaban for any indication postabdominal transplant. METHODS: All adult patients, ≥ 18 years of age, who received apixaban for any indication post kidney, liver, simultaneous liver-kidney (SLK), or simultaneous pancreas-kidney (SPK) transplant were included. Electronic health records were retrospectively reviewed for patient demographics, past medical history, and apixaban characteristics, including indication, dose, frequency, and the use of parenteral anticoagulation lead-in for acute thrombosis. The primary outcome was the incidence of thromboembolic events. Secondary outcomes included any bleeding events. In addition, adherence to package label dosing recommendations, based on indication of anticoagulation, was evaluated. RESULTS: Among the 79 patients included, 51 (65%) were kidney, 18 (23%) were liver, 7 (9%) were SPK, and 3 (4%) were SLK transplant recipients. The most common indications for apixaban use were acute venous thromboembolism (VTE) (n = 33, 42%), stroke prevention with atrial fibrillation (AF) (n = 18, 23%), and treatment of GT (n = 13, 17%). The primary outcome of the incidence of any thromboembolic event was 3.8% (n = 3), which occurred at a median of 304 (IQR 168-309) days after apixaban initiation. CONCLUSIONS: Apixaban dosing was consistent with labeled dosing for the majority of the cohort for labeled indications, and the observed incidence of thromboembolic events in this cohort was low, with no excess identified relative to published literature. Our data support the use of apixaban for stroke prevention in AF or treatment of VTE or GT in patients who have received an abdominal transplant; however, risk factors for bleeding events, specifically in those with GT, should be further explored.