For more information regarding Bristol-Myers Squibb Clinical Trial participation, please visit www.BMSStudyConnect.com Inclusion Criteria: - Males and females, 37 weeks adjusted gestational age to < 18 years of age - Congenital or acquired heart diseases requiring chronic anticoagulation for thromboprophylaxis (eg, single ventricle physiology including all 3 stages of palliation, dilated cardiomyopathy, Kawasaki disease with coronary aneurysms, and pulmonary hypertension) - Eligible participants include those who newly start anticoagulants and those who are currently on VKA or LMWH or other anticoagulants for thromboprophylaxis - Able to tolerate enteral medication [eg, by mouth, nasogastric tube, or gastric tube] - Participants 28 days to < 3 months must be able to tolerate oral/NGT/GT feeds for at least 5 days prior to randomization Exclusion Criteria: - Recent thromboembolic events less than 6 months prior to enrollment - Use of aggressive life-saving therapies such as ventricular assist devices (VAD) or extracorporeal membrane oxygenation (ECMO) at the time of enrollment - Artificial heart valves and mechanical heart valves - Known inherited bleeding disorder or coagulopathy (e.g. hemophilia, von Willebrand disease, etc.) - Active bleeding at the time of enrollment - Any major bleeding other than perioperative in the preceding 3 months - Known intracranial congenital vascular malformation or tumor - Confirmed diagnosis of a GI ulcer - Known antiphoshpholipid syndrome (APS). Other protocol defined inclusion/exclusion criteria could apply