HYPOTHERMIC CONTINUOUS MACHINE PERFUSION IMPROVES METABOLIC PRESERVATION AND FUNCTIONAL RECOVERY IN DCD HEART GRAFTS.

Abstract

Background: the number of heart transplants is declining since the 2000s because of organ shortage. Donation after cardiac death (DCD) is an alternative source of grafts. Hearts from DCD donors are not transplanted due to warm ischemia and possible poor graft function. Hypothermic machine perfusion (MP) has proven to be superior to cold storage (CS) for the preservation of kidneys, livers or lungs from DCD. We investigated in a large animal mod-el whether MP improves preservation of DCD hearts and allow its use for transplantation. Method: 16 pig hearts were retrieved after anoxia induced cardiac arrest and cardioplegia. They were randomized in 2 groups: 8 hearts preserved on CS; 8 hearts on MP (Modified Lifeport© System, Organ Recovery Systems©, Itasca, Il). The preservation solution was KPS-1 in both groups. After a period of 4 hours, the grafts were reper-fused on a Langendorff during 60 min. Myocardial biopsies were performed at baseline, post-preservation and post-reperfusion to quantify oxidative metabolism by measuring lactate, nucleotides, phosphocreatine (Pcr) and creatine (Cr). Contractility index (CI) was assessed in vivo before cardioplegia with a Millar catheter and during reperfusion with an intraventricular balloon. Results: compared to MP, hearts preserved on CS showed significant higher lactate levels (57,1±23,4 vs 21,4±12,2 μmoles/g heart; p<0,001), higher AMP/ATP ratio (0,53±0,25 vs 0,11±0,11; p<0,0001) and lower PCr/Cr ratio (9,7±5,3 vs 25,2±11; p<0,001) after preservation. Compared to baseline, CI decreased by 26±7% the CS group while it remained unchanged in the MP group (p<0,05). Conclusion: Compared to MP, DCD hearts preserved on CS suffer more severe ischemia during preservation, as shown by a higher lactate and lower energy states. Grafts preserved on MP recovered well after reperfusion, while function was depressed in grafts preserved on CS