Abstract 2430: Targeted alpha-v Integrin Imaging Defines Spatial and Temporal Changes in the Angiogenic Process Post Myocardial Infarction
Introduction/Hypothesis: Angiogenesis may be an indicator of ongoing remodeling post myocardial infarction (MI). We have previously demonstrated that an alpha-v integrin targeted compound Tc99m-NC100692 (692) (GE Healthcare) reflects myocardial angiogenesis. We hypothesized that serial SPECT imaging with 692 will provide a non-invasive index of spatial and temporal variation of the angiogenic process after MI.
Methods: MI was created in dogs by 6 hr angioplasty occlusion of either the proximal LAD or LCX. Serial dual isotope 692 and Tl-201 SPECT imaging was performed in control dogs (n=2) and dogs euthanized at 1 wk (n=2), 3 wk (n=2) or 12 wks (n=4) post MI. All dogs were imaged before MI, and at 1 wk, 2 wk, 3 wk, 6 wk, 9 wk and 12 wk time points until euthanasia. Cine MRI was performed acutely and at the terminal timepoint. Hearts were excised and cut into 5mm thick slices for gamma well counting. Segments were segregated based on normalized Tl-201 activity into infarct, border and remote regions. NC100692 activity was expressed as % injected dose/g.
Results: Serial SPECT images demonstrate maximum 692 uptake 2–3 weeks post MI, which correlated with well counting data summarized in figure⇓. A significant increase in 692 uptake was seen in infarct region at all time points relative to control, remote and border regions.
Conclusions: Serial SPECT imaging with 692 provides a non-invasive spatial and temporal index of the angiogenic process associated with post-MI remodeling. Angiogenesis remained localized in infarct and border regions. Although maximum 692 uptake occurred early, increased 692 activity was seen as late as 12 wks post MI suggesting persistence of the angiogenic process.