Fig. 2.

Transplant listing criteria and the relation to the Human Explanted Heart Program (HELP). A. Conceptual diagram depicting the heart transplant listing eligibilities for both recipients (left) and donors (right), and the sources of failing and non-failing hearts for HELP biobank. Left: Flow chart illustrating the eligibility, detailed evaluations, and referral status for being listed as heart transplant candidates. Right: The inclusion criteria, specific assessments, and types of donor hearts are delineated. Note that transplantations were limited by the scarcity of matched ideal donor hearts, with the potential to improve by extending the clinical acceptance of donor hearts. HELP biobank: Our heart pools are composed of native failing hearts from transplant recipients, the apical core from patients receiving an LVAD, and non-failing (namely marginal, and unmatched ideal) hearts. B. Imbalanced heart donor-recipient matching in Canada. The HF population was divided into adult (blue lines) and pediatric (green lines) subpopulations; accordingly, the statistics recorded the annual numbers of patients needing heart transplants (round marker) and the ones got transplanted (square marker) from 2006 to 2018. C. Clinical potentials of expanded application of “marginal hearts”. Annual total numbers of HF patients (including adult and pediatrics) were collected at both national (dash lines) and provincial (solid lines) levels. The data from 2014 to 2018 demonstrated the advantageous outcomes in terms of increased heart transplant cases (red lines) and simultaneously reduced number of patients awaiting (brown lines) at the national level, while the heart transplant rate remained relatively stable in Alberta during the past five years. Statistics were obtained from the Canadian Organ Replacement Register affiliated with the Canadian Institute for Health Information [39,40]. CA: Canada; AB: Alberta.