The goal of this study was to determine whether myocardial glucose uptake after repetitive ischemia differs in response to coronary occlusion-reperfusion versus supply-demand ischemia induced by dobutamine. Although glucose metabolism is increased after myocardial ischemia, the metabolic effect of supply-demand ischemia induced by dobutamine may increase glucose metabolism within remote myocardium. This would make it difficult to discriminate postischemic from remote myocardium with glucose tracers. Methods: Eighteen swine with a hydraulic occluder and flow probe on the circumflex artery underwent repetitive ischemia. In group 1 (n = 9), the circumflex artery was occluded, whereas in group 2 (n = 9), circumflex flow was decreased by 30% before dobutamine (40 μg/kg/min intravenously). Each pig underwent 15 min of ischemia, twice per day for 5 d. Echocardiography and PET to determine myocardial glucose (18F-FDG) uptake were performed after final ischemia, and tissue was later analyzed for activation of Akt, p38 mitogen-activated protein, and adenosine monophosphate (AMP) kinase. Results: Wall thickening in the circumflex region was lower than in remote regions in both groups. 18F-FDG uptake in the circumflex region was similar in groups 1 and 2 (0.22 ± 0.03 and 0.23 ± 0.04 μmol/min/g, respectively; not statistically significant). In the remote region, 18F-FDG uptake was lower than in the circumflex region in group 1 (0.14 ± 0.03 μmol/min/g; P < 0.05) but was similar to that in the circumflex region in group 2 (0.20 ± 0.03 μmol/min/g; not statistically significant). AMP kinase activity in the remote region was significantly lower than in the circumflex region in group 1 but was similar to that in the circumflex region in group 2. Conclusion: Unlike repetitive coronary artery occlusion-reperfusion, repetitive supply-demand ischemia with dobutamine alters glucose uptake within the remote myocardium, possibly as a result of AMP kinase activation. Clinically, these data suggest that 18F-FDG studies have a limited role in discriminating postischemic from remote myocardium after dobutamine stress.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Nuclear Medicine|
|State||Published - Jan 1 2003|
- Glucose metabolism
- Myocardial ischemia
- Remote tissue