Objectives: Improving methods of donor heart preservation may permit prolonged storage and remote procurement of cardiac allografts. We hypothesized that continuous, sanguineous perfusion of the donor heart in the beating, working state may prolong myocardial preservation. Methods: We developed a portable perfusion apparatus for use in donor heart preservation. Contractile, metabolic, and vasomotor functions were monitored simultaneously in an isolated swine heart. The metabolic state was monitored by myocardial tissue pH. Vasomotor function was assessed in isolated coronary ring chambers. Hearts were randomized into 3 groups: group I (n = 5), cardioplegic arrest, 12-hour storage at 4°C with modified Belzer solution, and 2-hour sanguineous reperfusion in the working state; group II (n = 6), 12-hour continuous perfusion in the beating working state, 30 minutes of arrest (to simulate re-implantation time), and 2 hours of reperfusion, as above; group III (n = 7), coronary ring control hearts. Results: At 2 hours of reperfusion, left ventricular developed pressure in group II was higher than in group I (mean ± standard deviation: 90 ± 6 mm Hg, 53 ± 15 mm Hg, P = .005). Significantly less myocardial edema was observed in group II than in group I (73 % ± 4 %, 80 % ± 1% water content, P = .01). Significantly less myocardial acidosis was noted in group II than in group I during preservation (pH 7.3 ± 0.01, 6.1 ± 0.03, P < .001) and reperfusion (pH 7.3 ± 0.008, 6.8 ± 0.05, P < .001). Coronary endothelial vasomotor function was better preserved in group II than in group I as evidenced by dose-response relaxation of coronary rings to 10-8 mol/L bradykinin (37%, 55% Δbaseline, P = .01). Conclusion: This new method extends the current preservation limit and avoids time-dependent ischemic injury, thereby allowing for distant procurement of donor organs.