F5 and antiphospholipid syndrome: It is effectively treated with medical anticoagulation and sometimes requires surgical intervention. Recurrent DVT presents challenges, and the anticoagulation strategy is determined by etiology and the presence or absence of both modifiable and non-modifiable risk factors. Certain primary thrombophilic conditions can cause recurrent and breakthrough DVT, such as the factor V Leiden mutation, antiphospholipid syndrome, the prothrombin 20210 mutation, and antithrombin deficiency.