Preservation of non-heart-beating cardiac donor using isolated myocardal perfusion: The importance of initial controlled reperfusion

Background: Warm ischemia is a major cause of cardiac allograft dysfunction in non-heart-beating donors (NHBDs). To minimize myocardial ischemia, we employed an isolated myocardial perfusion technique during preservation. The purpose of present study was to investigate an optimal duration of initial controlled reperfusion for NHBD hearts. Methods: Cardiac arrest was induced in 18 donor pigs (20kg) by asphyxia. The hearts were harvested 30 min after global warm ischemia following cardiac arrest and were immediately reperfused from the aortic root with leukocyte-depleted blood cardioplegia (20°C, 40 mmHg). Animals were divided into 3 groups (n 6 each) according to the duration of initial controlled reperfusion; group I 5 min, II 20 min and III 60 min. After the initial controlled reperfusion, oxygenated leukocyte-depleted blood was perfused for 20 min (20°C, 40 mmHg), and then perfusion pressure was increased to 60 mmHg and temperature was elevated stepwise to 37°C over 30 min. Keeping heart beating by isolated myocardial perfusion, orthotopic transplantation was performed. After 1 hour weaning from CPB, cardiac output (CO) and LV Emax were measured on epinephrine of 0.1 /kg/min. Lactate extraction was measured during coronary reperfusion and heart weight was determined at the end of the experiment. Results: Recovery rates of post-transplant cardiac function in group II were better than in group I and III (CO: 41 5 vs. 61 9 vs. 44 4%, P 0.05; LV Emax: 36 9 vs. 64 8 vs. 42 6%, P 0.05). Posttransplant heart weight in group II was less than in group I and III (20 1 vs. 10 1 vs. 19 6%, P 0.05). Lactate extractions at 20 minutes after initiation of reperfusion returned to 0 in group II and III. Conclusions: The NHBD cardiac allograft preserved by isolated myocardial perfusion best recovers, when initial controlled reperfusion with leukocyte-depleted blood cardioplegia continues for 20 minutes.