Correlation between apoptosis and left ventricular remodeling in subacute phase of myocardial ischemia and reperfusion

BACKGROUND: To investigate whether an apoptotic process demonstrated by (99m)Tc-annexin-V ((99m)Tc-AV) uptake correlates with left ventricular remodeling (LVR) after myocardial infarction, we assessed (99m)Tc-AV uptake in rat model of myocardial ischemia and reperfusion. METHODS: The left coronary artery (LCA) of 15 rats was occluded for 20 to 30 min, followed by reperfusion. After 2 weeks, (99m)Tc-AV was injected, and then 1 h later, (201)Tl was injected after reocclusion of the LCA. Dual-tracer autoradiography was performed to assess (99m)Tc-AV uptake and the area at risk (AAR) by (201)Tl defect. (99m)Tc-AV uptake ratio was calculated by dividing the count density of the AAR by that of the normally perfused area. In short-axis LV slices, LV cavity dilation index (DI) was calculated by dividing the area of LV cavity by that of the whole LV area. LV wall-thinning ratio (WTR) was calculated by dividing the LV wall thickness in the AAR by that of the normally perfused area. RESULTS: Significant (99m)Tc-AV uptake in the AAR was observed in 10 rats. DI was significantly higher in rats with positive (99m)Tc-AV uptake than in rats without uptake. WTR was smaller in rats with positive (99m)Tc-AV uptake than in rats without uptake. CONCLUSIONS: The data suggest (99m)Tc-AV uptake in injured myocardium might correlate with LVR at 2 weeks after myocardial ischemia and reperfusion.