- Patients with macrohaematuria, active haemorrhage within the past two months, organ lesions at risk of bleeding (e.g. active peptic ulcer, haemorrhagic cerebrovascular accident, aneurysms), a history of episodes of clinically evident haemorrhage, major surgery in the previous month or an increase in the risk of bleeding due to any disturbance of haemostasis which would contraindicate the anticoagulant therapy, with the exception of bleedings episodes directly caused by tumour subjected to the surgical intervention.