Repeated stunning precedes myocardial hibernation in progressive multiple coronary artery obstruction
Repeated stunning precedes myocardial hibernation in progressive multiple coronary artery obstruction
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DOI：
10.1016/s0735-1097(99)00467-2
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发表时间：
1999-12-01
影响因子：
24
通讯作者：
Vanhaecke, J
中科院分区：
文献类型：
--
作者：
Shivalkar, B;Flameng, W;Vanhaecke, J
方法在18只犬的右冠状动脉（RC）和回旋支（CX）近端放置Ameroid缩窄器，在左前降支（LAD）近端（管腔狭窄+/-77%）放置硅胶管套囊。每周进行一次二维超声心动图检查区域功能（前[A]、下后[IP]、壁增厚[WT]）和短轴缩短分数（FS）。结果术后4周行冠状动脉造影证实RC和CX闭塞，并伴有侧支化和LAD狭窄。最初，观察到A和IP WT的间歇性降低，随后持续（AWT：16 +/- 3%; IPWT：16 +/-4%，FS：20 +/-4%，p < 0.005 vs，基线[BS]）。使用多巴酚丁胺时，观察到双相反应（A和IP WT在5-15之间改善，功能障碍在20-30 μ g/kg/min之间）。8周时处死7只犬，显示正常RF但降低的透壁CR（A：75 +/- 18%; IF：46 +/- 22%对照）。7只狗在8周时接受了LAD的PTCA，AWT逐渐改善，在12周时恢复正常（AWT：30 +/-5%，p < 0.001 vs，8周）。处死时，A壁的RF和CR正常，但IP区域的内膜下RF降低（BS的64%）。此外，所有犬的活检样本均显示正常组织学结果和高能磷酸盐含量。放射性配体结合分析，使用I-125-iodocyanopindolol显示下调β-肾上腺素能受体密度在功能障碍的地区与control.CONCLUSIONS相比，在这个犬模型的可行的，侧支依赖性和可逆性功能障碍心肌，有早期发作功能障碍，随后持续功能障碍，最初与正常RF，后来与subendovascular低灌注。(C)1999年由美国心脏病学会。
OBJECTIVE The aim of this study was to characterize a regional myocardial flow-function relationship in collateral dependent myocardium produced by multiple coronary artery obstruction.METHODS Ameroid constrictors were placed around the proximal right (RC) and circumflex (CX) coronary arteries and a silicon tubing cuff around the proximal LAD (left anterior descending artery) (luminal stenosis +/-77%) in 18 dogs. Weekly two-dimensional echocardiography was performed for regional function (anterior [A], inferoposterior [IP], wall thickening [WT]), and fractional shortening (FS). Colored microspheres injected at baseline and before sacrifice, before and after dipyridamole (0.5 mg/kg) injection, determined resting flow (RF) and coronary reserve (CR), respectively.RESULTS Coronary angiography performed at four weeks after surgery confirmed occlusion of RC and CX with collateralization and a tight stenosis of LAD. Initially, an episodic reduction in A and IP WT was observed which became persistent later (AWT: 16 +/- 3%; IPWT: 16 +/- 4%, FS: 20 +/- 4%, p < 0.005 vs, baseline [BS]). With dobutamine a biphasic response (improvement in A and IP WT between 5-15 and dysfunction between 20-30 mu g/kg/min) was observed. Seven dogs were sacrificed at eight weeks and showed normal RF but reduced transmural CR (A: 75 +/- 18%; IF: 46 +/- 22% of control). Seven dogs underwent PTCA of the LAD at eight weeks and showed gradual improvement in AWT with normalization at 12 weeks (AWT: 30 +/- 5%, p < 0.001 vs, eight weeks). At sacrifice RF and CR in the A wall were normal but there was reduced subendocardial RF in the IP region (64% of BS). Further, biopsy samples showed normal histological findings and high energy phosphate content in all dogs. Radioligand binding assays using I-125-iodocyanopindolol showed downregulation of beta-adrenergic receptor density in the dysfunctional regions compared with control.CONCLUSIONS In this canine model of viable, collateral dependent and reversibly dysfunctional myocardium, there was early episodic dysfunction followed by persistent dysfunction which was initially associated with normal RF and later with subendocardial hypoperfusion. (C) 1999 by the American College of Cardiology.