Aaronson K D, Mancini D M
Division of Circulatory Physiology, Columbia University College of Physicians and Surgeons, Columbia-Presbyterian Medical Center, New York, N.Y. 10032, USA.
J Heart Lung Transplant. 1995 Sep-Oct;14(5):981-9.
Peak exercise oxygen consumption provides valuable short-term prognostic information in patients with heart failure. However, peak exercise oxygen consumption is determined not only by the cardiac output response to exercise but also by age, gender, and muscle mass. We investigated whether percentage of predicted maximal exercise oxygen consumption rather than an absolute value may be a better predictor of survival.
Peak exercise oxygen consumption was measured and percentage of predicted maximal exercise oxygen consumption was derived from two standard formulas (Wasserman and Astrand) in 272 ambulatory patients referred for transplant evaluation. The predictive ability of these variables was determined by comparison of Kaplan-Meier curves, univariable proportional-hazards models, and receiver operating characteristic curves.
Neither method of determining percentage of predicted maximal exercise oxygen consumption significantly improved the prediction of survival over peak exercise oxygen consumption alone. Overall model discrimination, as assessed by area under the receiver operating characteristic curve, was not significantly improved with percentage of predicted maximal exercise oxygen consumption (Wasserman) rather than weight-normalized peak exercise oxygen consumption (0.71 +/- 0.04 versus 0.66 +/- 0.04; Z = 1.60, p = 0.11). All of the difference between percentage of predicted maximal exercise oxygen consumption-Wasserman and peak exercise oxygen consumption resulted from differences in women (areas under receiver operating characteristic curve = 0.68 +/- 0.09 and 0.74 +/- 0.09; p = 0.14); results for men were the same (both areas = 0.68 +/- 0.04).
Normalization of peak exercise oxygen consumption for predicted values adds only minimal prognostic information. A peak exercise oxygen consumption < 14 ml/kg/min remains a reasonable guideline by which to time heart transplantation.
运动峰值耗氧量为心力衰竭患者提供了有价值的短期预后信息。然而，运动峰值耗氧量不仅取决于运动时的心输出量反应，还受年龄、性别和肌肉量的影响。我们研究了预测最大运动耗氧量的百分比而非绝对值是否可能是更好的生存预测指标。
对272例因移植评估而前来就诊的门诊患者测量运动峰值耗氧量，并根据两个标准公式（瓦瑟曼公式和阿斯特兰德公式）得出预测最大运动耗氧量的百分比。通过比较Kaplan-Meier曲线、单变量比例风险模型和受试者工作特征曲线来确定这些变量的预测能力。
两种确定预测最大运动耗氧量百分比的方法，相较于单独使用运动峰值耗氧量，均未显著改善生存预测。通过受试者工作特征曲线下面积评估的总体模型辨别能力，使用预测最大运动耗氧量百分比（瓦瑟曼公式）而非体重标准化运动峰值耗氧量时，并未得到显著改善（0.71±0.04对0.66±0.04；Z = 1.60，p = 0.11）。预测最大运动耗氧量百分比-瓦瑟曼公式与运动峰值耗氧量之间的所有差异均源于女性的差异（受试者工作特征曲线下面积分别为0.68±0.09和0.74±0.09；p = 0.14）；男性的结果相同（两个面积均为0.68±0.04）。
将运动峰值耗氧量标准化为预测值仅增加了极少的预后信息。运动峰值耗氧量＜每分钟14毫升/千克仍然是合理的心脏移植时机指导指标。
