Ex Vivo Heart Perfusion Versus Cold Storage in Prolonged Preservation Period: A Juvenile Porcine Experimental Model

Cross-clamp times greater than or equal to 4 hours are critical for donor heart viability. We compared cold storage (CS) and normothermic ex vivo heart perfusion (EVHP) during prolonged preservation using a juvenile porcine model. Twenty-two piglet hearts (~10 kg) were assigned to CS or EVHP for 6 or 8 hours, followed by 2 hours of working-mode (WM) perfusion. Metabolism, cardiac function, and cell damage were compared using two-sample t-tests or Fisher's exact tests, and temporal changes during perfusion were assessed using linear mixed-effects models and generalized estimating equations. During EVHP, the minimal rate of pressure change decreased, and arterial lactate levels increased after 5-6 hours. Compared to CS, EVHP hearts showed higher left atrial pressure (6 vs. 0 mm Hg, p = 0.011), arterial lactate levels during WM (p < 0.001), and NFκB-p65 levels (p = 0.002) at 6 hours, and lower cardiac output (90 vs. 120% of normal, p = 0.026), higher left atrial pressure (7 vs. 3 mm Hg, p = 0.009), higher arterial lactate levels during WM (p < 0.001), and increased neutrophil infiltration (p = 0.033) at 8 hours. Ex vivo heart perfusion hearts deteriorated beyond 5-6 hours and showed greater hemodynamic, metabolic, and inflammatory changes at both 6 and 8 hours. Ex vivo heart perfusion enhancements reducing immune response and inflammation are crucial for expanding the donor pool.