Ex vivo resuscitation and evaluation of hearts after 22 minutes of normothermic cardiac arrest.

Objective: The aim was to resuscitate and evaluate hearts ex vivo after 22 min of cardiac arrest with the goal of increasing the number of usable hearts from controlled donation after circulatory death (cDCD).

Design: Eight pigs (39-61 kg) underwent 22 min of ventricular fibrillation, after which the heart was first perfused in vivo for three minutes with an oxygenated, erythrocyte-containing cardioplegic preservation solution. The heart was then explanted and perfused ex vivo with the same solution for three hours at 18 °C in a transportable heart preservation system. Functional evaluation was performed ex vivo (n = 7), while one heart underwent orthotopic transplantation and was monitored for 24 h.

Results: The seven hearts evaluated ex vivo easily pumped twice the cardiac output measured in vivo. The transplanted heart maintained normal blood pressure, blood gases, and urine output throughout the 24-hour observation period. At the end of this period the aortic pressure was 104/80 mmHg with a heart rate of 129 beats per minute. Intravenous administration of 20, 40, and 100 µg adrenaline resulted in an aortic pressures of 238/171, 284/196, and 287/201 mmHg with corresponding heart rates of 162, 188, and 223 beats per minute.

Conclusion: Hearts exposed to 22 min of cardiac arrest were successfully resuscitated ex vivo and demonstrated adequate function when evaluated.