Fallavollita J A
Department of Veterans Affairs Western New York Health Care System and Department of Medicine at the University at Buffalo, NY 14214, USA.
Circulation. 2000 Aug 22;102(8):908-14. doi: 10.1161/01.cir.102.8.908.
Previous studies of hibernating myocardium in the fasting state have shown regionally increased (18)F-2-deoxyglucose (FDG) uptake with a marked transmural gradient. We hypothesized that this adaptation to chronic ischemia might be associated with altered maximal FDG uptake.
Pigs were instrumented with a 1.5-mm proximal left anterior descending artery (LAD) stenosis. Studies were conducted 106+/-4 days later on anesthetized animals with complete LAD occlusion and anteroapical dysfunction. In fasting animals (n=9), FDG uptake in dysfunctional LAD regions was 2-fold higher than in normally perfused myocardium (7.9+/-1.2 versus 4. 0+/-0.5 micromol x min(-1) x 100 g(-1), P<0.05), with a pronounced transmural gradient (endocardial/epicardial ratio 2.56+/-0.19 versus 1.25+/-0.03, P<0.05). Euglycemic, hyperinsulinemic clamp (insulin clamp, n=8) produced a 5- to 9-fold increase in FDG uptake, but there was no longer a regional difference in accumulation (LAD, 37. 8+/-4.2 versus normal, 36.4+/-5.1 micromol x min(-1) x 100 g(-1), P=NS) and the transmural distribution was uniform. FDG uptake in the fasting state varied inversely with coronary flow during vasodilation. In contrast, during insulin clamp there was no relation between FDG uptake and vasodilated flow, resulting in a reduced spatial heterogeneity in individual samples (relative dispersion=SD/mean; fasting, 52+/-5% versus insulin, 24+/-2%, P<0.05).
In the fasting state, FDG uptake in pigs with hibernating myocardium was heterogeneous and was increased in dysfunctional regions with a marked transmural gradient and high spatial heterogeneity. In contrast, FDG uptake was more homogeneously distributed during insulin clamp with (1) uptake in dysfunctional myocardium similar to remote normal regions, (2) uniform transmural distribution, and (3) reduced spatial heterogeneity.
先前关于禁食状态下冬眠心肌的研究显示，（18）F - 2 - 脱氧葡萄糖（FDG）摄取呈区域性增加，且存在明显的透壁梯度。我们推测这种对慢性缺血的适应性改变可能与最大FDG摄取的变化有关。
对猪进行1.5毫米近端左前降支（LAD）狭窄手术。在106±4天后，对麻醉状态下LAD完全闭塞且前壁心尖功能障碍的动物进行研究。在禁食动物（n = 9）中，功能障碍的LAD区域的FDG摄取比正常灌注心肌高2倍（7.9±1.2对4.0±0.5微摩尔·分钟-1·100克-1，P < 0.05），存在明显的透壁梯度（心内膜/心外膜比值2.56±0.19对1.25±0.03，P < 0.05）。正常血糖、高胰岛素钳夹（胰岛素钳夹，n = 8）使FDG摄取增加5至9倍，但摄取量不再存在区域差异（LAD，37.8±4.2对正常，36.4±5.1微摩尔·分钟-1·(100克)-1，P = 无显著差异），且透壁分布均匀。禁食状态下的FDG摄取与血管舒张期的冠状动脉血流呈负相关。相反，在胰岛素钳夹期间，FDG摄取与血管舒张期血流无关，导致单个样本中的空间异质性降低（相对离散度 = 标准差/均值；禁食，52±5%对胰岛素，24±2%，P < 0.05）。
在禁食状态下，冬眠心肌猪的FDG摄取是不均匀的，在功能障碍区域增加，存在明显的透壁梯度和高空间异质性。相比之下，在胰岛素钳夹期间，FDG摄取分布更均匀，表现为：（1）功能障碍心肌中的摄取与远处正常区域相似；（2）透壁分布均匀；（3）空间异质性降低。
