Steroids Limit Myocardial Edema During Ex Vivo Perfusion of Hearts Donated After Circulatory Death

Abstract

Normothermic exvivo heart perfusion (EVHP) has been shown to improve the preservation of hearts donated after circulatory arrest and to facilitate clinical successful transplantation. Steroids are added to the perfusate solution in current clinical EVHP protocols; however, the impact of this approach on donor heart preservation has not been previously investigated. We sought to determine the impact of steroids on the inflammatory response and development of myocardial edema during EVHP. Thirteen pigs were anesthetized, mechanical ventilation was discontinued, and a hypoxemic cardiac arrest ensued. A 15-minute warm-ischemic standoff period was observed, and then hearts were resuscitated with a cardioplegic solution. Donor hearts were then perfused exvivo in a normothermic beating state for 6 hours with 500 mg of methylprednisolone (steroid: n= 5) or without (control: n= 8). The addition of steroids to the perfusate solution reduced the generation of proinflammatory cytokines (interleukin-6, -8, -1β, and tumor necrosis factor-α) and the development of myocardial edema during EVHP (percentage of weight gain: control= 26% ± 7% versus steroid= 16% ± 10%, p= 0.049). Electron microscopy suggested less endothelial cell edema in the steroid group (injury score: control= 1.8 ± 0.2 versus steroid= 1.2 ± 0.2, p= 0.06), whereas perfusate troponin-I (control= 11.9 ± 1.9 ng/mL versus steroid= 9.5 ± 2.4 ng/mL, p= 0.448) and myocardial function were comparable between the groups. The addition of methylprednisolone to the perfusion solution minimizes the generation of proinflammatory cytokines and development of myocardial edema during normothermic exvivo perfusion of hearts donated after circulatory arrest.