Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA.
J Card Fail. 2009 Nov;15(9):756-62. doi: 10.1016/j.cardfail.2009.05.012. Epub 2009 Jul 3.
The lowest minute ventilation (VE) and carbon dioxide production (VCO(2)) ratio during exercise has been suggested to be the most stable and reproducible marker of ventilatory efficiency in patients with heart failure (HF). However, the prognostic power of this index is unknown.
A total of 847 HF patients underwent cardiopulmonary exercise testing (CPX) and were followed for 3 years. The associations between the lowest VE/VCO(2) ratio, maximal oxygen uptake (peak VO(2)), the VE/VCO(2) slope, and major events (death or transplantation) were evaluated using proportional hazards analysis; adequacy of the predictive models was assessed using Akaike information criterion (AIC) weights. There were 147 major adverse events. In multivariate analysis, the lowest VE/VCO(2) ratio (higher ratio associated with greater risk) was similar to the VE/VCO(2) slope in predicting risk (hazard ratios [HR] per unit increment 2.0, 95% CI 1.1-3.4, and 2.2, 95% CI 1.3-3.7, respectively; P < .01), followed by peak VO(2) (HR 1.6, 95% CI 1.1-2.4, P=.01). Patients exhibiting abnormalities for all 3 responses had an 11.6-fold higher risk. The AIC weight for the 3 variables combined (0.94) was higher than any single response or any combination of 2. The model including all 3 responses remained the most powerful after adjustment for beta-blocker use, type of HF, and after applying different cut points for high risk.
The lowest VE/VCO(2) ratio adds to the prognostic power of conventional CPX responses in HF.
运动时最低分钟通气量（VE）与二氧化碳产生量（VCO₂）比值被认为是心力衰竭（HF）患者通气效率最稳定和可重复的标志物。然而，该指标的预后价值尚不清楚。
共有 847 例 HF 患者接受心肺运动测试（CPX）并随访 3 年。使用比例风险分析评估最低 VE/VCO₂ 比值、最大摄氧量（peak VO₂）、VE/VCO₂斜率与主要事件（死亡或移植）之间的相关性；使用赤池信息量准则（AIC）权重评估预测模型的充分性。共有 147 例主要不良事件。多变量分析显示，最低 VE/VCO₂ 比值（比值越高，风险越大）与 VE/VCO₂斜率在预测风险方面具有相似性（每单位递增的风险比[HR]分别为 2.0、95%CI 1.1-3.4 和 2.2、95%CI 1.3-3.7；P<0.01），其次是 peak VO₂（HR 1.6、95%CI 1.1-2.4，P=0.01）。3 种反应均异常的患者风险增加 11.6 倍。3 个变量结合的 AIC 权重（0.94）高于任何单个反应或任何 2 个反应的组合。在调整β受体阻滞剂使用、HF 类型以及应用不同高危切点后，纳入所有 3 个反应的模型仍然最有力。
在 HF 中，最低 VE/VCO₂ 比值增加了传统 CPX 反应的预后价值。
