Metabolic adaptation to a gradual reduction in myocardial blood flow.
Metabolic adaptation to a gradual reduction in myocardial blood flow.
复制标题
代谢适应心肌血流量逐渐减少。
作者：
A. Arai;S. E. Grauer;C. Anselone;G. Pantely;J. Bristow
背景
对局部冠状动脉血流量减少 20% 至 50% 的研究揭示了许多代谢和功能适应，表明心脏会下调能量需求和收缩力以应对缺血。与之前关于冠脉血流突然变化的研究相比，我们测试了心脏是否可以随着冠脉血流的逐渐减少而相应地减少 ATP 消耗，或者短暂的代谢异常是否是这一过程的必要触发因素。
方法和结果
从 0 到 35 分钟，10 只急性麻醉并装有仪器的猪的平均左冠状动脉前降支血流量每分钟减少约 1%。然后冠状动脉血流量在 35 至 60 分钟之间保持恒定，最终净血流量减少 35%。尽管全身血流动力学保持稳定，但局部左心室收缩期壁增厚显着下降（60 分钟时从控制值 45 +/- 11% 降至 18 +/- 11%，P < .001），而磷酸化电位没有持续下降（通过跨壁或心内膜下磷酸肌酸与 ATP 比率下降 < 2% 来评估），并且心肌乳酸产生量最少（4 +/- 44 mumol.min-1 x 100 g-1)。
结论
缺血的代谢标志物，例如磷酸肌酸与 ATP 的比率、ATP 含量、乳酸含量和乳酸产量，在缺血逐渐恶化的过程中减弱。因此，轻度缺血的收缩异常可以在缺血的代谢证据极少的情况下发生。心肌能量需求的下调几乎可以与冠脉血流量的逐渐下降保持同步。
BACKGROUND
Studies during 20% to 50% reductions in regional coronary blood flow have revealed a number of metabolic and functional adaptations that suggest the heart downregulates energy requirements and contractility in response to ischemia. In contrast to prior studies of sudden changes in coronary blood flow, we tested whether the heart could reduce ATP consumption commensurate with a gradual decrease in coronary blood flow or whether transient metabolic abnormalities are a necessary trigger in this process.
METHODS AND RESULTS
From 0 to 35 minutes, mean left anterior descending coronary artery blood flow was reduced by approximately 1% per minute in 10 acutely anesthetized and instrumented swine. Coronary blood flow then was held constant between 35 and 60 minutes at the resulting 35% net blood flow reduction. Although systemic hemodynamics remained stable, a significant decrease in regional left ventricular systolic wall thickening developed (from control value of 45 +/- 11% to 18 +/- 11% at 60 minutes, P < .001) without a sustained decrease in the phosphorylation potential (as assessed by a < 2% decrease in either the transmural or subendocardial phosphocreatine-to-ATP ratio) and with minimal myocardial lactate production (4 +/- 44 mumol.min-1 x 100 g-1).
CONCLUSIONS
Metabolic markers of ischemia such as ratio of phosphocreatine to ATP, ATP content, lactate content, and lactate production were blunted during this protocol of gradually worsening ischemia. Thus, contractile abnormalities of mild ischemia can develop with minimal metabolic evidence of ischemia. The downregulation of myocardial energy requirements can almost keep pace with the gradual decline in coronary blood flow.
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影响因子：
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DOI：
10.1056/nejm199012063232304
发表时间：
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期刊：
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影响因子：
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