The purpose of this study is to determine whether tafamidis, an oral medication used to delay disease progression in adults with certain forms of transthyretin amyloidosis (ATTR), is effective in treating patients with heart transplants that also have ATTR, including managing non-cardiac manifestations such as neuropathy. Neuropathy may include symptoms like numbness, tingling, imbalance, constipation, diarrhea, or low blood pressure. Participants will undergo screening that includes a blood draw, physical exam, medical history review, and completion of quality-of-life surveys. Once screening is complete, participants will begin taking tafamidis daily for 12 months. Tafamidis has been approved by the U.S. Food and Drug Administration (FDA) to treat cardiac ATTR, but its use in this study is considered investigational.