Age over 85 years, creatinine clearance <10 ml / min, severe circulatory shock with a dose of norepinephrine greater than 1.0 pg / Kg / min, Chronic renal patients on hemodialysis, chronic Child B and C liver disease, advanced diseases (active neoplasia, heart failure functional class III and IV, COPD in chronic use of oxygen with more than 2 exacerbations in the last year, advanced dementia, bedridden patient with significant sequelae of stroke or traumatic brain injury, cardiorespiratory arrest, pregnant women, recent major surgery in the last 3 weeks, recent stroke in the last 3 months, presence of active bleeding, presence of blood dyscrasia such as: hemophilia, Von Willebrand factor deficiency, etc., participation in another clinical investigation with associated intervention, formal indication for oral anticoagulation for other reasons such as: pulmonary embolism, acute coronary syndrome, etc.

Age over 85 years, creatinine clearance <10 ml / min, severe circulatory shock with a dose of norepinephrine greater than 1.0 pg / Kg / min, Chronic renal patients on hemodialysis, chronic Child B and C liver disease, advanced diseases (active neoplasia, heart failure functional class III and IV, COPD in chronic use of oxygen with more than 2 exacerbations in the last year, advanced dementia, bedridden patient with significant sequelae of stroke or traumatic brain injury, cardiorespiratory arrest, pregnant women, recent major surgery in the last 3 weeks, recent stroke in the last 3 months, presence of active bleeding, presence of blood dyscrasia such as: hemophilia, Von Willebrand factor deficiency, etc., participation in another clinical investigation with associated intervention, formal indication for oral anticoagulation for other reasons such as: pulmonary embolism, acute coronary syndrome, etc.