Extension of hemorrhage after reperfusion of occluded coronary artery: contrast echocardiographic assessment in dogs.

Abstract

The aim of this study was to elucidate the progression of intramural hemorrhage complicated by reperfusion with the use of myocardial contrast echocardiography. Although hemorrhagic infarction is known to occur in ischemia followed by reperfusion, its onset and sequence have not been well characterized. In 20 anesthetized dogs, 3-h occlusion of the left circumflex-coronary artery was followed by reperfusion. The area at risk during coronary occlusion was approximately 25%. Myocardial contrast echocardiogram was examined, and the time-intensity curves for both ischemic and nonischemic areas were obtained at baseline, at 3 min after reperfusion and then at 15-min intervals until 90 min after reperfusion. The wall thickness of both areas was also measured. Gross hemorrhage in the reperfused areas was observed in five dogs (Group H) but not in seven dogs (Group NH). All wall segments were opacified at 3 min after reperfusion in both groups. However, the contrast defect spread significantly with time after reperfusion in Group H but not in Group NH (18.7 +/- 3.4% and 3.3 +/- 1.8%, respectively, at 90 min after reperfusion p < 0.005). The wall of the risk area at 90 min after reperfusion had thickened to 1.3 times baseline thickness in Group H but was unchanged in Group NH. The other eight dogs were excluded from study because of fatal arrhythmias or the existence of collateral circulation during coronary occlusion. Both progression of the contrast defect area on myocardial contrast echocardiography and a gradual thickening of the wall with reperfusion are characteristic of hemorrhagic infarction.