Recurrence of VTE on anticoagulation (ROA) affected 3% of patients, with nearly half of events attributable to modifiable causes, and true anticoagulant failure (ACF) occurring in only 17.3% of ROA cases.
The incidence of VTE recurrence on anticoagulation (ROA) was 3.0% in a large registry cohort.
The most frequently documented reasons for ROA were altered absorption, recent interruption of therapy, and medication dosing issues.
Malignancy was present in a large majority of patients with ROA, with a substantial proportion having metastatic disease.
Half of ROA events were attributed to a modifiable cause, while true anticoagulant failure (ACF) was identified in only 17.3% of patients.
After a recurrent VTE event, the most common management strategy was transition to an alternative anticoagulant, most frequently enoxaparin.
The study proposes distinct definitions for ROA and ACF to improve clarity in describing VTE recurrence during anticoagulation.
This research suggests that blood clot recurrence in patients already taking blood thinners (anticoagulants) — a situation called 'recurrence on anticoagulation' or ROA — affects about 3% of patients treated for venous thromboembolism (VTE). Importantly, the study found that approximately half of these recurrences were linked to preventable or fixable causes, such as problems with how the medication was absorbed by the body, issues with dosing, or recent interruptions in taking the medication. Cancer was extremely common among affected patients, present in over 70% of cases, with nearly half of those having advanced (metastatic) cancer. The study also makes an important distinction between ROA — any recurrence while on anticoagulation — and true 'anticoagulant failure' (ACF), which is recurrence with no identifiable or fixable cause. Only about 17% of ROA patients truly had ACF by this stricter definition, meaning the medication genuinely appeared to stop working without any explainable reason. When doctors did need to change treatment after a recurrence, the most common approach was to switch to a different blood thinner, most often enoxaparin (a type of injectable low-molecular-weight heparin). This research matters because it highlights that many blood clot recurrences in anticoagulated patients are not inevitable medication failures — they may be preventable with careful attention to how patients are taking their medications, potential drug absorption problems, and treatment interruptions. The clear definitions proposed for ROA versus ACF could help clinicians better evaluate and communicate about these cases, and the described management strategies offer practical guidance for a challenging clinical situation.
Brunton N, Wysokinski W, Hodge D, Vlazny D, McBane R, Houghton D, et al.. (2026). Etiology and management of venous thromboembolism recurrence in patients anticoagulated for venous thromboembolism: a single-center study.. Research and practice in thrombosis and haemostasis. https://doi.org/10.1016/j.rpth.2026.106847