- age < 18 years-old - patients with indication for full anticoagulation during inclusion (for example, diagnosis of venous thromboembolism, atrial fibrillation, mechanical valve prosthesis) - platelets < 50,000 /mm3 - use of acetylsalicylic acid > 100 mg per day - use of p2y12 inhibitor (clopidogrel, prasugrel, ticagrelor) - chronic use of nsaids - hypersensitivity to apixaban - creatinine clearance < 30 ml/min - pregnancy or breastfeeding - patients contraindicated to anticoagulation (active bleeding, recent major surgery, blood dyscrasia or prohibitive hemorrhage risk as evaluated by the investigator) - 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 - 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)

- age < 18 years-old - patients with indication for full anticoagulation during inclusion (for example, diagnosis of venous thromboembolism, atrial fibrillation, mechanical valve prosthesis) - platelets < 50,000 /mm3 - use of acetylsalicylic acid > 100 mg per day - use of p2y12 inhibitor (clopidogrel, prasugrel, ticagrelor) - chronic use of nsaids - hypersensitivity to apixaban - creatinine clearance < 30 ml/min - pregnancy or breastfeeding - patients contraindicated to anticoagulation (active bleeding, recent major surgery, blood dyscrasia or prohibitive hemorrhage risk as evaluated by the investigator) - 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 - 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)