Heart donation after cardiac death: preliminary study on an isolated, perfused swine heart after 20 minutes of normothermic ischemia.

ABSTRACT

BACKGROUND: We measured the functional and metabolic status of hearts submitted to normothermic ischemia before preservation through the use of an ex vivo pig heart model to assess the feasibility of donation after cardiac death (DCD) in heart transplantation. METHODS: Ten pigs were separated into 2 groups control (n = 6, brain-dead group) and DCD (n = 4, heart donation after cardiac death). In the control group, hearts were excised 20 minutes after the brachiocephalic trunk cross-clamping and were immediately reperfused. In DCD, hearts were excised 20 minutes after exsanguination and asphyxia, stored in the Centre de Résonance Magnétique Biologique et Médicale (CRMBM) solution for 2 hours, and then were reperfused. Cardioplegic arrest was induced with the use of 1 L of CRMBM solution (4°C) and the heart was reperfused for 60 minutes through the use of an ex vivo perfusion system in Langendorff mode with normothermic autologous blood. During reperfusion, functional parameters were analyzed. Biochemical assays were performed in myocardial effluents and freeze-clamped hearts. RESULTS: No electromechanical activity was found in DCD compared with control. Creatine kinase (CK) was higher at 2 minutes of reperfusion in DCD versus control (P = .005). Adenosine triphosphate was lower in DCD versus control (P = .0019). Malondialdehyde, an oxidative stress index, was present only in DCD. The nitric oxide (NO) pathway was impaired in DCD versus control, with lower eNOS expression (P < .0001) and total nitrate concentration content (P = .04). CONCLUSIONS: We reported no cardiac functional and metabolic recovery in the DCD group after normothermic ischemia and reperfusion, which indicates that a single immersion of the cardiac graft during storage does not provide an optimal protection. New strategies in heart preservation are necessary for recruiting heart donation after cardiac death.