Enhancement of cardioplegic protection with a lecithin-based perfluoroadamantane emulsion

Myocardial protection during surgically-induced cardiac ischemic arrest can be improved by promoting aerobic metabolism throughout the ischemic episode. Because of the problems encountered with both blood cardioplegia and oxygenated crystalloid cardioplegia, we assessed the effects of a recently developed lecithin-based perfluoroadamantane in an isolated isovolumic buffer-perfused rat heart model of cardioplegic arrest. Forty hearts divided into 4 equal groups underwent 90 min of global ischemia at 30.C followed by 45 min of normothermic reperfusion. During arrest, hearts were infused at 30 min intervals with either standard crystalloid cardioplegic solution, lecithin-enriched cardioplegic solution or cardioplegic solution mixed with a lecithin-based perfluorocarbon emulsion (F-dimethyladamantane in one group, and F-methyladamantane in the other). All perfusates were fully oxygenated prior to use. Although fluorocarbon-treated hearts had reduced postischemic coronary flows, they yielded a significantly better recovery of systolic indexes (developed pressure and left ventricular dP/dt) than the controls. Postischemic diastolic pressures were not different among the 4 groups. We conclude that, under severe conditions of ischemia, the Adamantech fluorocarbon emulsion significantly improves cardioplegic protection. The clinical relevance of these data is supported by the fact that, unlike previously developed pluronic-based fluorocarbon emulsions, the present solution has no complement-activating properties.