Low-dose apixaban or rivaroxaban as secondary prophylaxis of upper extremity deep vein thrombosis.

Upper extremity deep vein thrombosis (UEDVT) may occur without inciting factor or may be secondary to malignancy, surgery, trauma, central venous catheter or related to thoracic outlet syndrome (TOS). International guidelines recommend anticoagulant treatment for at least three months, in particular the use of vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs). No data on extended anticoagulant therapy and reduced dose of DOACs have been reported in patients affected by UEDVT with persistent thrombotic risk (active cancer, major congenital thrombophilia) or without affected vein recanalization. In our retrospective observational study, including 43 patients, we treated secondary UEDVT with DOACs. In the acute phase of thrombosis (median time of 4 months), we used therapeutic dose of DOACs; the 32 patients with permanent thrombotic risk factors or without recanalization of the UEDVT were shifted to low-dose DOACs (apixaban 2.5 mg twice daily or rivaroxaban 10 mg daily). During therapy with full-dose DOACs, 1 patient presented recurrence of thrombosis; no thromboembolic events were observed during treatment with low-dose DOACs. During full-dose treatment, 3 patients presented minor hemorrhagic complications; no hemorrhagic events were observed during DOACs at low dose. We think our preliminary data could support the indication to extend the anticoagulation with dose reduction of DOACs in patients affected by UEDVT and no-transient thrombotic risk. These data should be confirmed in randomized controlled prospective study.