Eggleston A M, Bolukoglu H, Liedtke A J, Nellis S H
Section of Cardiology, University of Wisconsin, Madison 53792.
Cardioscience. 1990 Sep;1(3):199-208.
The purpose of this study was to apply step-wise multiple linear regression analysis retrospectively to an array of mechanical and metabolic measurements chosen because they had the potential to predict the extent of contractile recovery from a prescribed duration of myocardial ischemia. Data were acquired from the extracorporeally perfused, intact, working pig heart which was rendered regionally ischemic (60% reduction in anterior descending coronary flow) for 45 minutes and reperfused to aerobic levels for a final 30-50 minutes. Mechanical recovery was defined by the percentage systolic shortening and the area circumscribed by left ventricular pressure-segment length loops. Data were taken from 39 control hearts and from 16 hearts treated with oxfenicine, an agent which we have previously used to alter mechanical function by its interference with fatty acid metabolism. Despite the fixed nature of the protocol in affecting ischemic hypoperfusion, a wide range of mechanical responses encompassing hypo- and dyskinesis was produced during ischemia, followed by mechanical stunning during reflow. Of the parameters surveyed, regional indices of mechanical performance, together with perfusate pH and PCO2, best predicted recovery. Along with the heart rate, these predictors gave correlations of 0.875 for percentage systolic shortening and 0.766 for the length-pressure loop in control hearts. The analyses were also sensitive to the influence of pharmacological intervention with oxfenicine in that several parameters lost statistical significance for percentage systolic shortening and two were added (heart rate and end-diastolic length) for the length-pressure loop. Separate statistical models for oxfenicine-treated hearts gave correlations of 0.905 for percentage systolic shortening and 0.915 for the length-pressure loop. The data suggest that step-wise multiple linear regression analysis provides new insights toward our understanding of the mechanisms of mechanical stunning in myocardial reperfusion.
本研究的目的是对一系列机械和代谢测量值进行回顾性逐步多元线性回归分析，这些测量值之所以被选用，是因为它们有可能预测在规定时长的心肌缺血后收缩功能恢复的程度。数据采集自体外灌注的、完整的、工作中的猪心脏，该心脏局部缺血（前降支冠状动脉血流减少60%）45分钟，然后再灌注至有氧水平持续最后30 - 50分钟。机械恢复通过收缩期缩短百分比和左心室压力 - 节段长度环所围成的面积来定义。数据取自39个对照心脏和16个用奥昔芬净治疗的心脏，奥昔芬净是一种我们之前用于通过干扰脂肪酸代谢来改变机械功能的药物。尽管该方案在影响缺血性低灌注方面具有固定性，但在缺血期间产生了广泛的机械反应，包括运动减弱和运动障碍，随后在再灌注期间出现机械性休克。在所调查的参数中，机械性能的区域指标以及灌注液pH值和PCO2最能预测恢复情况。与心率一起，这些预测指标在对照心脏中，收缩期缩短百分比的相关性为0.875，长度 - 压力环的相关性为0.766。这些分析对奥昔芬净的药理干预影响也很敏感，因为对于收缩期缩短百分比，几个参数失去了统计学意义，而对于长度 - 压力环则增加了两个参数（心率和舒张末期长度）。奥昔芬净治疗心脏的单独统计模型显示，收缩期缩短百分比的相关性为0.905，长度 - 压力环的相关性为0.915。数据表明，逐步多元线性回归分析为我们理解心肌再灌注中机械性休克的机制提供了新的见解。
