MON-023 - Venous Thromboembolism Prophylaxis with Rivaroxaban in ACTH-Dependent Cushing Syndrome: A Single-Centre Retrospective Cohort Study

Background:
Patients with ACTH-dependent Cushing syndrome (CS) have a markedly increased risk of venous thromboembolism (VTE), yet evidence-based thromboprophylaxis strategies are lacking. In 2019, our centre implemented a protocolised approach using oral rivaroxaban 10 mg once daily for VTE prophylaxis in this high-risk population.

Objective:
To evaluate the safety and effectiveness of prophylactic rivaroxaban in reducing VTE events in patients with ACTH-dependent CS.

Methods:
We conducted a single-centre retrospective cohort study of adults with ACTH-dependent CS (pituitary and ectopic) managed between January 2012 and January 2025. Outcomes before protocol implementation (pre-2019; no routine prophylaxis) were compared with those after introduction of rivaroxaban prophylaxis (post-2019). VTE events were radiologically confirmed. Bleeding complications were classified as major or minor. Haematological parameters and adherence and adherence to prophylaxis were assessed.

Results:
Seventy patients were included (29 pre-2019; 41 post-2019) with comparable baseline characteristics. Pituitary-dependent Cushing disease predominated in both cohorts (26/29 pre-2019; 34/41 post-2019). In the pre-2019 cohort, 4/29 patients (13.7%) experienced six VTE events, occurring both pre-operatively (up to eight months before surgery) and within one month post-operatively. In the post-2019 cohort, five patients experienced seven VTE events prior to endocrine assessment for hypercortisolism and before initiation of rivaroxaban. Two of these patients had recurrent VTE and were already receiving therapeutic anticoagulation. No new or recurrent VTE events occurred following prophylaxis initiation. No major or minor bleeding complication were observed. Haematological indices remained stable, and all patients completed the prescribed prophylaxis course (median duration, 7.9 months).

Conclusions:
This is the first study to evaluate oral rivaroxaban for VTE prophylaxis in ACTH-dependent CS. Compared with a 13.7% VTE rate prior to 2019, protocolised rivaroxaban use was associated with complete absence of new or recurrent VTE events and no observed bleeding complications. These findings support early initiation at diagnosis and continuation through the peri- and postoperative period in ACTH-dependent CS.

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