ROLE OF PLATELET-ACTIVATING-FACTOR ON EXTRAVASCULAR LUNG WATER AFTER CORONARY REPERFUSION IN DOGS

Platelet-activating factor (PAF), one of the harmful substances releas ed after coronary reperfusion, has been reported to increase pulmonary vascular permeability and induce pulmonary edema. In this study, we s ought to examine the possible role of PAF in the genesis of pulmonary edema after coronary reperfusion. Extravascular lung water (EVLW) was measured by the thermal-dye double indicator dilution method during co ronary ligation and after reperfusion in situ in dogs. The proximal le ft anterior descending coronary artery was occluded for 15 min and rep erfused in 5 dogs (group 1), while five other dogs (group 2) were trea ted with PAF-antagonist (TCV-309, 1 mg/kg) before coronary artery occl usion. EVLW and hemodynamic indices were measured at baseline, 15 min of coronary occlusion, and 15 and 30 min after coronary reperfusion. E VLW increased at 15 min of coronary occlusion in both groups, but ther e was no significant difference between the two groups (6.4 to 10.3 ml /kg and 5.4 to 7.1 ml/kg in groups 1 and 2, respectively). After coron ary reperfusion, EVLW increased further in group 1 (6.4 to 16.5 ml/kg, p < 0.01), but no further increase was observed in group 2 at 30 min after coronary reperfusion. There were no significant differences in h emodynamic indices between the two groups throughout the test. Thus, P AF-antagonist attenuated the increase in EVLW after coronary reperfusi on independent of hemodynamic indices, and hence, PAF may play an impo rtant role in the genesis of pulmonary edema caused by coronary reperf usion.