CONTINUOUS PERFUSION OF DONOR HEARTS IN THE BEATING STATE EXTENDS PRESERVATION TIME AND IMPROVES RECOVERY OF FUNCTION

Objectives: Improving methods of donor heart preservation may permit p rolonged storage and remote procurement of cardiac allografts. We hypo thesized that continuous, sanguineous perfusion of the donor heart in the beating, working state may prolong myocardial preservation. Method s: We developed a portable perfusion apparatus for use in donor heart preservation. Contractile, metabolic, and vasomotor functions were mon itored 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 gro ups: group I(n = 5), cardioplegic arrest, 12-hour storage at 4 degrees C with modified BeIzer solution, and 2-hour sanguineous reperfusion i n the working state; group II (n = 6), 12-hour continuous perfusion in the beating working state, 30 minutes of arrest (to simulate re-impla ntation time), and 2 hours of reperfusion, as above; group III (n = 7) , coronary ring control hearts. Results: At 2 hours of reperfusion, le ft 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 th an in group I(73% +/- 4%, 80% +/- 1% water content, P = .01). Signific antly less myocardial acidosis was noted in group II than in group I d uring preservation (pH 7.3 +/- 0.01, 6.1 +/- 0.03, P < .001) and reper fusion (pH 7.3 +/- 0.008, 6.8 +/- 0.05, P < .001). Coronary endothelia l vasomotor function was better preserved in group II than in group I as evidenced by dose-response relaxation of coronary rings to 10(-8) m ol/L bradykinin (37%, 55% Delta baseline, P = .01). Conclusion: This n ew method extends the current preservation limit and avoids time-depen dent ischemic injury, thereby allowing for distant procurement of dono r organs.