The recently concluded prospective Portable Organ Care System (OCS) Heart trial to Evaluate the Safety and Effectiveness of The Portable Organ Care System Heart for Preserving and Assessing Expanded Criteria Donor Hearts for Transplantation (EXPAND) demonstrated that the use of ex vivo perfusion for expanded-criteria hearts may be a viable method for increasing the use of donor hearts. We sought to estimate the potential impact of ex vivo expanded-criteria heart perfusion on the donor pool in the United States by using a large national transplant registry. After applying the inclusion criteria of EXPAND, 8637 potentially eligible donors were identified in the U.S. between January 1, 2015, and June 30, 2019, representing a substantial potential increase in the donor pool.