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.