Abstract 3687: Intracoronary Administered Endothelial Progenitor Cells (EPC) Preferentially Home to and Improve Viability of the Core Infarct Region in Patients with Acute Myocardial Infarction
Background: Initial clinical trials suggest a beneficial effect of intracoronary infusion of EPC on myocardial function in patients with acute myocardial infarction (AMI). However, the extent and spatial distribution of cells homing to the infarcted myocardium after intracoronary infusion are unknown. Therefore, EPC, isolated from peripheral blood and cultivated for 3 days, were ex-vivo labelled with radioactive Indium-111-Oxin similar to a leucocyte szintigraphy procedure and infused into the infarct vessel during low pressure balloon occlusion 6±2 days after reperfused AMI in 8 patients. Cell homing was assessed by total body gamma camera imaging of Indium-111 activity and FDG-PET was subsequently performed to assess myocardial viability.
Results: One hour after intracoronary administration of labelled EPC, a mean of 8.9±5.8% of total radioactivity was detected in the heart. Graphical display of cardiac Indium-111- and FDG-activity using bulls-eye-views revealed a perfect match with highest Indium activity co-localizing with lowest FDG-activity. FDG-PET-derived viability of the infarcted myocardium was the most important predictor of EPC homing (Indium activity) with a strong negative correlation (r=-0.74; p<0.05). In 9 additional AMI patients undergoing repeated FDG-PET 4 months after intracoronary EPC administration, viability was significantly increased in the infarcted area (from 0.61±0.1 during AMI to 0.77±0.2 at 4 months follow-up; p=0.003). Most importantly, FDG-PET-derived increase in myocardial viability was significantly (p<0.05) greater in the infarct core compared to the infarct border region. In parallel, the increase in infarct core viability was a strong predictor of improved wall motion in the total infarct area (r=0.53; P=0.01).
Conclusion: In patients with AMI, intracoronary administered EPC preferentially home to the infarct core region. Decreased FDG-PET-derived myocardial viability is the strongest predictor of increased EPC homing. The preferential homing of EPC to the infarct core region is directly correlated with increased viability and improved contractile function of the infarcted segments at 4 months follow-up.