Isolated distal DVT (iDDVT) is the most frequent clinical presentation of VTE and is associated with a significant morbidity and risks of long-term complications. Data from clinical trials highlighted that patients with iDDVT might require some level of AC treatment. However, the optimal anticoagulant intensity is uncertain, and it is plausible that the best benefit/risk ratio for AC might be achieved with lower intensity doses rather than therapeutic doses.
The principal research question of the Apixaban to treat calf vein thrombosis (API-CALF) study is to determine whether, after a conventional course of 7 days of Apixaban 10mg BID, Apixaban 2.5mg BID (experimental arm) is non inferior to Apixaban 5 mg BID (standard arm) in preventing VTE recurrence and bleeding in patients with iDDVT. Patients will be treated with Apixaban for a total of 3 months. In that perspective we will conduct an international multicentre open-label assessor-blinded study