MYOCARDIAL EFFECTS OF EXPERIMENTAL ACUTE BRAIN-DEATH - EVALUATION BY HEMODYNAMIC AND BIOLOGICAL STUDIES

Background. Because of problems concerning the functional quality of h eart transplants, more and more interest has been focused on the physi ologic changes occurring during brain death, one of the major possible contributing factors to the myocardial alterations. Methods. The aim of this study was to describe the link between acute experimental brai n death and myocardial metabolism. This was achieved by in vivo 3-hour hemodynamic and biological (myocardial lactate production) studies an d then in vitro 6-hour phosphorus-31 nuclear magnetic resonance spectr oscopy. Two groups of pigs were involved in the study: group I (n = 10 ) as control and group II (n = 10) as brain-dead animals. Results. Wit hin the first hour, we observed a strong increase in myocardial activi ty associated with the onset of myocardial lactate production, lasting 2 hours and corresponding to a myocardial anaerobic metabolism period . Despite the apparent normalization before excision of the hearts, ph osphorus-31 nuclear magnetic resonance spectroscopy revealed a signifi cant decrease in adenosine triphosphate levels in group II when compar ed with group I. Conclusions. We conclude that, in our study, acute ex perimental brain death is associated with an early and transient perio d of myocardial anaerobic metabolism and adenosine triphosphate consum ption. These myocardial consequences of brain death could partially ex plain some observations of heart graft dysfunction.