F5 and paroxysmal nocturnal hemoglobinuria: Systemic lupus erythematosus, antiphospholipid syndrome, factor V Leiden presence, paroxysmal nocturnal haemoglobinuria, hyperhomocysteinemia, deficiency of the proteins C and S, and thrombocytopenia induced by heparin are the hypercoagulation diseases that are known as the risk factors for OVT [7, 8].