F5 and paroxysmal nocturnal hemoglobinuria: Hypercoagulation conditions as systemic lupus erythematosus, antiphospholipid syndrome, presence of factor V Leiden, paroxysmal nocturnal haemoglobinuria, hyperhomocysteinaemia, protein C and S deficiency and heparin induced thrombocytopenia are all reported as risk factors for OVT [1,7].