|Subject||ex vivo heart perfusion, machine perfusion, heart transplant, organ preservation, organ evaluation, functional assessment, oxygen consumption, lactate metabolism|
Ex vivo heart perfusion (EVHP) may facilitate resuscitation of discarded donor hearts and expand the donor pool; however, a reliable means of demonstrating organ viability prior to transplantation is required. Therefore, we sought to identify metabolic and functional parameters that predict myocardial performance during EVHP. To evaluate the parameters over a broad spectrum of organ function, we obtained hearts from 9 normal pigs and 37 donation after circulatory death pigs and perfused them ex vivo. Functional parameters obtained from a left ventricular conductance catheter, oxygen consumption, coronary vascular resistance, and lactate concentration were measured, and linear regression analyses were performed to identify which parameters best correlated with myocardial performance (cardiac index: mL·min⁻¹·g⁻¹). Functional parameters exhibited excellent correlation with myocardial performance and demonstrated high sensitivity and specificity for identifying hearts at risk of poor post-transplant function (ejection fraction: R² = 0.80, sensitivity = 1.00, specificity = 0.85; stroke work: R² = 0.76, sensitivity = 1.00, specificity = 0.77; minimum dP/dt: R² = 0.74, sensitivity = 1.00, specificity = 0.54; tau: R² = 0.51, sensitivity = 1.00, specificity = 0.92), whereas metabolic parameters were limited in their ability to predict myocardial performance (oxygen consumption: R² = 0.28; coronary vascular resistance: R² = 0.20; lactate concentration: R² = 0.02). We concluded that evaluation of functional parameters provides the best assessment of myocardial performance during EVHP, which highlights the need for an EVHP device capable of assessing the donor heart in a physiologic working mode.