THE ROLE OF PLATELET-ACTIVATING-FACTOR IN REGIONAL MYOCARDIAL ISCHEMIA-REPERFUSION INJURY

Background. This swine model was designed to elucidate the role of pla telet-activating factor in regional myocardial ischemia-reperfusion in jury. Methods. In groups 1 and 2 (n = 12 each), the left anterior desc ending coronary artery was ligated for 60 minutes to induce regional m yocardial ischemia followed by 6 hours of reperfusion. Group 1 receive d the platelet-activating factor antagonist TCV-309 before ischemia, w hereas group 2 did not. Group 3 (n = 3) had a sham operation. Results. Animals in group 2 exhibited significant (p < 0.05) hemodynamic insta bility and myocardial depression during the reperfusion period. Despit e preventive measures, 7 of the 12 animals experienced severe dysrhyth mias in the form of atrial and ventricular fibrillation leading to car diac arrest. In contrast, animals in group 1 in whom the effects of pl atelet-activating factor were blocked by the specific platelet-activat ing factor receptor antagonist TCV-309 were hemodynamically stable and had significantly (p < 0.05) better myocardial function. This signifi cant difference in global myocardial function between the groups was o bserved in the presence of similar morphologic findings and regional m yocardial function. Conclusions. These results suggest that platelet-a ctivating factor has a definite influence on global myocardial dysfunc tion associated with regional myocardial ischemia-reperfusion injury. (C) 1998 by The Society of Thoracic Surgeons.