Detection of recent myocardial ischaemia by molecular imaging of P-selectin with targeted contrast echocardiography

Abstract

Aims: We hypothesized that molecular imaging of endothelial P-selectin expression with targeted myocardial contrast echocardiography (MCE) could identify recently ischaemic myocardium without infarction. Methods and results: The microvascular behaviour of P-selectin-targeted (MBp) and control (MBc) microbubbles was assessed by intravital microscopy of the cremaster muscle in mice. Targeted MCE imaging with MBp and MB c was performed in mice after brief left anterior descending (LAD) occlusion and reperfusion and in open- and closed-chest controls. Regional wall motion and perfusion by MCE were assessed during occlusion and after reperfusion. On intravital microscopy, ischaemia-reperfusion produced a 10-fold increase (P < 0.01) in venular attachment for MBp. Attachment for MBc was rare. With myocardial ischaemia-reperfusion, LAD occlusion produced hypoperfusion and wall motion abnormalities that resolved after 45 min of reperfusion. At 45 min, signal enhancement in the post-ischaemic region was four-fold greater (P < 0.05) for MBp vs. MBc. MB p produced low-level enhancement in non-ischaemic myocardium in all open-chest animals, suggesting P-selectin expression from surgical cardiac exposure. Conclusion: Molecular imaging of P-selectin with targeted MCE can identify the presence of recently ischaemic myocardium in the absence of necrosis and after resolution of hypoperfusion and post-ischaemic stunning. This technique can potentially provide a method for risk stratifying patients with acute chest pain. © The European Society of Cardiology 2007. All rights reserved.