RELATIONSHIP BETWEEN PROGRESSIVE MICROVASCULAR DAMAGE AND INTRAMYOCARDIAL HEMORRHAGE IN PATIENTS WITH REPERFUSED ANTERIOR MYOCARDIAL-INFARCTION - MYOCARDIAL CONTRAST ECHOCARDIOGRAPHIC STUDY

Background Recent studies indicated that ischemic microvascular damage may be reversible or progressive after coronary reflow. Intramyocardi al hemorrhage is a phenomenon that reflects severe microvascular injur y. We examined the relationship between temporal changes in microvascu lar perfusion patterns detected by myocardial contrast echocardiograph y (MCE) and intramyocardial hemorrhage detected by magnetic resonance imaging (MRI) in patients with acute myocardial infarction (AMI). Meth ods and Results The study population consisted of 24 patients with ant erior AMI. All patients underwent MCE shortly after reflow and in the chronic stage (a mean of 31 days after reflow). Wall motion score (WMS ) was determined as the sum of 16 segmental scores (dyskinetic/akineti c=3 to normal=0) at days 1 and 31. Gradient-echo acquisition and gadol inium-DTPA-enhanced spin-echo MRI were performed within 10 days after reflow. In MCE shortly after reflow, 16 patients (67%) showed contrast enhancement and the other 8 patients (33%) showed a sizable contrast defect. In the chronic stage, a persistent contrast defect was observe d in 7 of 8 patients with a contrast defect shortly after reflow. Cons istent contrast enhancement was observed in 12 of 16 patients (75%) wi th contrast enhancement shortly after reflow, indicating that a contra st defect newly appeared in 4 patients (25%). Intramyocardial hemorrha ge was detected in 9 patients (38%): 5 of 7 patients with a persistent contrast defect and in all 4 patients with a new appearance of a cont rast defect during the chronic stage. The patients without hemorrhage showed a significant improvement in WMS compared with patients with he morrhage at day 31 (5+/-5 versus 19+/-6, P<.0005). Conclusions These r esults suggest that irreversible microvascular damage to the ischemic myocardium may cause intramyocardial hemorrhage after reflow, associat ed with impaired recovery of left ventricular function. Contrast enhan cement within the risk area shortly after reflow does not necessarily indicate long-term microvascular salvage.