Arena Ross, Guazzi Marco, Myers Jonathan
Department of Physical Therapy, Box 980224, Virginia Commonwealth University, Health Sciences Campus, Richmond, Virginia 23298-0224, United States.
Int J Cardiol. 2007 Apr 12;117(1):103-8. doi: 10.1016/j.ijcard.2006.04.058. Epub 2006 Jul 14.
The partial pressure of end-tidal carbon dioxide production (P(ET)CO2) at ventilatory threshold (VT) has been shown to be strongly correlated with cardiac output during exercise in patients with heart failure (HF), but few data are available regarding its prognostic utility.
The purpose of this study was to assess the ability of P(ET)CO2 to predict cardiac-related events in a group of subjects with HF.
One hundred and thirty subjects diagnosed with compensated HF underwent cardiopulmonary exercise testing (CPX). Peak oxygen consumption (VO2), the minute ventilation-carbon dioxide production (VE/VCO2) slope and P(ET)CO2 were determined.
Receiver operating characteristic (ROC) curve analysis revealed that P(ET)CO2 at the ventilatory threshold (VT) was a significant predictor of cardiac-related events (ROC area=0.82, p<0.001). The optimal P(ET)CO2 at a VT threshold value for separating high (< or =) and low (>) risk groups was 36.1 mm Hg (77% sensitivity, 69% specificity). In a multivariate Cox regression analysis, P(ET)CO2 at VT added significant predictive value to the VE/VCO2 slope and peak VO2.
These results indicate that P(ET)CO2 during CPX is a significant predictor of cardiac-related events in patients with HF. Clinical assessment of this variable in patients with HF undergoing CPX may therefore be warranted.
在心力衰竭（HF）患者运动过程中，通气阈值（VT）时的呼气末二氧化碳分压（P(ET)CO2）已被证明与心输出量密切相关，但关于其预后效用的数据却很少。
本研究旨在评估P(ET)CO2预测一组HF患者心脏相关事件的能力。
130例诊断为代偿性HF的受试者接受了心肺运动试验（CPX）。测定了峰值耗氧量（VO2）、分钟通气量与二氧化碳产量比值（VE/VCO2）斜率和P(ET)CO2。
受试者工作特征（ROC）曲线分析显示，通气阈值（VT）时的P(ET)CO2是心脏相关事件的显著预测指标（ROC曲线面积=0.82，p<0.001）。用于区分高（≤）和低（>）风险组的VT阈值下的最佳P(ET)CO2为36.1 mmHg（灵敏度77%，特异性69%）。在多变量Cox回归分析中，VT时的P(ET)CO2对VE/VCO2斜率和峰值VO2增加了显著的预测价值。
这些结果表明，CPX期间的P(ET)CO2是HF患者心脏相关事件的显著预测指标。因此，对接受CPX的HF患者进行该变量的临床评估可能是必要的。
