- patients with indication for full anticoagulation during inclusion (for example, diagnosis of venous thromboembolism, atrial fibrillation, mechanical valve prosthesis); - platelets < 50,000 /mm3 - need for asa therapy > 100 mg; - need for p2y12 inhibitor therapy (clopidogrel, ticagrelor or prasugrel); - chronic use of non-hormonal anti-inflammatory drugs; - sustained uncontrolled systolic blood pressure (bp) of ≥180 mmhg or diastolic bp of ≥100 mmhg; - inr > 1,5; - patients contraindicated to full anticoagulation (active bleeding, liver failure, blood dyscrasia or prohibitive hemorrhage risk as evaluated by the investigator); - criteria for disseminated intravascular coagulation (dic); - a history of hemorrhagic stroke or any intracranial bleeding at any time in the past or current intracranial neoplasm (benign or malignant), cerebral metastases, arteriovenous (av) malformation, or aneurysm; - active cancer (excluding non-melanoma skin cancer) defined as cancer not in remission or requiring active chemotherapy or adjunctive therapies such as immunotherapy or radiotherapy; - hypersensitivity to rivaroxaban; - use of strong inhibitors of cytochrome p450 (cyp) 3a4 and/or p-glycoprotein (p-gp) (e.g. protease inhibitors, ketoconazole, itraconazole) and/or use of p-gp and strong cyp3a4 inducers (such as but not limited to rifampin/rifampicin, rifabutin, rifapentine, phenytoin, phenobarbital, carbamazepine, or st. john's wort); - known hiv infection; - creatinine clearance < 30 ml/min according to the cockcroft-gault formula; - pregnancy or breastfeeding.

- patients with indication for full anticoagulation during inclusion (for example, diagnosis of venous thromboembolism, atrial fibrillation, mechanical valve prosthesis); - platelets < 50,000 /mm3 - need for asa therapy > 100 mg; - need for p2y12 inhibitor therapy (clopidogrel, ticagrelor or prasugrel); - chronic use of non-hormonal anti-inflammatory drugs; - sustained uncontrolled systolic blood pressure (bp) of ≥180 mmhg or diastolic bp of ≥100 mmhg; - inr > 1,5; - patients contraindicated to full anticoagulation (active bleeding, liver failure, blood dyscrasia or prohibitive hemorrhage risk as evaluated by the investigator); - criteria for disseminated intravascular coagulation (dic); - a history of hemorrhagic stroke or any intracranial bleeding at any time in the past or current intracranial neoplasm (benign or malignant), cerebral metastases, arteriovenous (av) malformation, or aneurysm; - active cancer (excluding non-melanoma skin cancer) defined as cancer not in remission or requiring active chemotherapy or adjunctive therapies such as immunotherapy or radiotherapy; - hypersensitivity to rivaroxaban; - use of strong inhibitors of cytochrome p450 (cyp) 3a4 and/or p-glycoprotein (p-gp) (e.g. protease inhibitors, ketoconazole, itraconazole) and/or use of p-gp and strong cyp3a4 inducers (such as but not limited to rifampin/rifampicin, rifabutin, rifapentine, phenytoin, phenobarbital, carbamazepine, or st. john's wort); - known hiv infection; - creatinine clearance < 30 ml/min according to the cockcroft-gault formula; - pregnancy or breastfeeding.