Abstract 1825: Perfusion Preservation vs Static Preservation for Cardiac Transplantation: Effects on Myocardial Function and Metabolism
Objectives: Current methods of preservation for heart transplantation limit safe storage intervals to approximately 6 hours. Some investigators have tested continuous perfusion devices to improve ischemic tolerance. However, the effects of continuous perfusion on cellular metabolism and myocardial edema development are not defined. This study was designed to test a continuous perfusion strategy for cardiac preservation in a large animal model.
Methods: Hearts from 45– 60 kg pigs were instrumented with sonomicrometry crystals and left ventricular (LV) catheters. LV function was quantified by preload-recruitable stroke work (PRSW). Hearts were arrested with Celsior solution, removed and stored in Celsior in an ice chest (n=4) or placed in a device providing continuous perfusion of Celsior at 10 ml/100g/min (n=4). All hearts were stored for 4 hours. At end-storage, samples of left atrium were frozen, extracted and analyzed by magnetic resonance spectroscopy (MRS). Hearts were then transplanted into recipient pigs and reperfused for 6 hours, with function measured hourly. At end-experiment, LV tissue water content was determined and serum CK-MB levels were measured.
Results: LV function was similar at baseline in both groups. By 3 hours of reperfusion, hearts stored with continuous perfusion demonstrated superior recovery of LV function (PRSW: 33.8 ± 8.3 vs 6.8 ± 5.0 mmHg, p < 0.05). MRS on samples at end-storage revealed a 20-fold increase in tissue lactate (expressed as lactate:alanine ratio) in static-preserved hearts (4.6 ±0.9 vs 0.2 ±0.1, p < 0.05). CKMB levels were higher in the static group (30.8 ± 9.0 vs 13.2 ± 2.7 ng/ml, p < 0.05). LV water content was similar in both groups (0.797 ± 0.012 vs. 0.795 ± 0.014, p = 0.45).
Conclusions: Continuous perfusion of donor hearts stored for transplantation offers better preservation of cardiac function after transplantation. This process nearly eliminates tissue lactate accumulation over 4 hours and results in lower myocardial necrosis as assessed by cardiac enzyme release. Under these perfusion conditions, no increase in myocardial edema occurs. This technology may offer an opportunity to improve early results after cardiac transplantation.