Monitoring of porcine myocardial ischemia and reperfusion by intravasal microdialysis

Objective-A novel application of microdialysis is studied where myocardial metabolism is semi-continuously monitored in the myocardial venous outflow during ischemia and reperfusion. Design-Microdialysis catheters were introduced into the great cardiac vein, the pulmonary artery, and the right external jugular vein in 20 anesthetized pigs. The left anterior descending artery was occluded in four separate groups of pigs for 0, 10, 15, and 60 min, respectively. Ischemia was followed by 120 min of reperfusion. Microdialysis samples were collected every 10-20 min and analyzed for lactate, pyruvate, glycerol, glutamate, and glucose. Results-Myocardial infarction was observed after 15 min of ischemia. Metabolic changes were observed only in the great cardiac vein. Lactate increased early during ischemia. After 60 min of ischemia an increase of the lactate/pyruvate ratio and glutamate was observed. Glycerol was progressively released during prolonged ischemia. Myocardial infarction resulted in an additional release of glycerol early in reperfusion. Conclusion-Intravasal microdialysis is a semi-continuous method to monitor myocardial metabolism and tissue damage during ischemia and reperfusion.