81] Oxygen scavengers in myocardial preservation during transplantation

Abstract

Publisher Summary This chapter discusses the benefits of oxygen scavengers in myocardial preservation during transplantation. Recently, several investigators have evaluated the potential application of xanthine oxidase inhibitors superoxide dismutase (SOD) and/or CAT as potential adjuvants for prolonged myocardial preservation during experimental heart transplantation. Jurmann evaluated the potential benefits of oxy radical scavengers in the setting of 3 hours of hypothermic ischemia and subsequent reperfusion using an isolated, perfused porcine heart model. Improved postischemic left ventricular developed pressure, dP/dtmax, and coronary blood flow were noted in the group receiving SOD and CAT compared to controls. No difference in lactate/pyruvate ratios in coronary sinus effluent was detected. The use of oxygen-derived free radical scavenging agents in experimental transplantation has resulted in improved postischemic ventricular function, suggesting indirectly that oxygen free radicals may be responsible for some component ofischemic/reperfusion injury. While most evidence is inferential, the measurement of lipid peroxidation products in the coronary effluent is direct evidence of ongoing lipid peroxidation. Unfortunately, the measurement of 2,4,6-tribromoanisole (TBA)-reactive species in vivo as a marker of oxygen free radical-mediated phospholipid oxidation is subject to numerous chemical interferences and is not specific to oxygen-dependent free radical lipid peroxidation. Given that xanthine oxidase is either absent or present in undetectable levels in human myocardium, questions remain about the potential role of oxygen-derived free radicals in human myocardial ischemia.