Background: Direct oral anticoagulants (DOAC) are the drug of choice in treating venous thromboembolism (VTE). During DOAC trials a 2-3% treatment failure rate has been observed. The predisposing factors for this treatment failure have not been addressed before in the literature.
Aims: Our aim was to elucidate associated factors of recurrent VTE under coagulation factor Xa inhibitor (FXaI) treatment.
Methods: Ten consecutive consultation cases of FXaI failure were included. Caprini, Padua, chronic thromboembolic pulmonary hypertension (CTEPH), and local VTE (Helsinki University Hospital) risk factor scores were assessed in all patients. Thrombophilia screen and coagulation activity follow-up were performed, and the anticoagulation strategy was individually tailored.
Results: The affected patients were young (mean age 37.5, range 22-55), and 6 were women. Although, initially many patients appeared to have unprovoked VTE, all were found with major VTE risk factors. Seven patients had chronic venous obstruction: 5 subclavian (thoracic outlet syndrome, TOS), one common iliac, and one with chronic paraplegia. Five patients had multiple VTE risk factors and 4 had thrombophilia. The VTE risk scores varied from the lowest (TOS patients) to the highest risk (multiple risk factors/thrombophilia). The FXaI failure occurred on average at 99 days of therapy (range 15-279) without evident noncompliance. D-dimer levels were low upon FXaI failure, and re-thrombosis was resistant to further anticoagulation. Initial VTE was pulmonary embolism (PE) in 8 patients, and upon recurrent PE, 6 of them developed CTEPH after the FXaI failure. All the CTEPH and majority (8/10) of all patients required mechanical/surgical interventions. All patients are alive with individually tailored anticoagulation.
Conclusion(s): Our series of these young patients illustrates the importance of the suspicion of TOS and thorough assessment of risk factors upon VTE and its reoccurrence. Impaired fibrinolysis deserves further studies. The tailoring of effective management strategies and follow-up are needed.
To cite this abstract in AMA style:
Kaksonen M, Pentikäinen M, Simonen P, Lassila R. Venous thromboembolism reoccurrence during factor Xa inhibitors in young patients associates with thoracic outlet syndrome and development of chronic thromboembolic pulmonary hypertension [abstract]. https://abstracts.isth.org/abstract/venous-thromboembolism-reoccurrence-during-factor-xa-inhibitors-in-young-patients-associates-with-thoracic-outlet-syndrome-and-development-of-chronic-thromboembolic-pulmonary-hypertension/. Accessed March 21, 2024.« Back to ISTH 2022 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/venous-thromboembolism-reoccurrence-during-factor-xa-inhibitors-in-young-patients-associates-with-thoracic-outlet-syndrome-and-development-of-chronic-thromboembolic-pulmonary-hypertension/