Additional Study Information: The purpose of this research study is to understand if aspirin is needed in patients heart failure implanted with the HeartMate 3. Patients with devices like the HeartMate 3 take two blood thinner medicines, specifically warfarin and aspirin. Patients implanted with devices like the HeartMate 3 experience both clotting and bleeding complications. Data suggest the HeartMate 3 may not require as much anticoagulation (blood thinners) as are normally used. This study will test if patients need aspirin together with warfarin or just warfarin alone.