Toste Alexandra, Soares Rui, Feliciano Joana, Andreozzi Valeska, Silva Sofia, Abreu Ana, Ramos Ruben, Santos Ninel, Ferreira Lurdes, Ferreira Rui Cruz
Serviço de Cardiologia, Hospital de Santa Marta, Lisboa, Portugal.
Rev Port Cardiol. 2011 Oct;30(10):781-7. doi: 10.1016/S0870-2551(11)70026-9.
A growing body of evidence shows the prognostic value of oxygen uptake efficiency slope (OUES), a cardiopulmonary exercise test (CPET) parameter derived from the logarithmic relationship between O(2) consumption (VO(2)) and minute ventilation (VE) in patients with chronic heart failure (CHF).
To evaluate the prognostic value of a new CPET parameter - peak oxygen uptake efficiency (POUE) - and to compare it with OUES in patients with CHF.
We prospectively studied 206 consecutive patients with stable CHF due to dilated cardiomyopathy - 153 male, aged 53.3±13.0 years, 35.4% of ischemic etiology, left ventricular ejection fraction 27.7±8.0%, 81.1% in sinus rhythm, 97.1% receiving ACE-Is or ARBs, 78.2% beta-blockers and 60.2% spironolactone - who performed a first maximal symptom-limited treadmill CPET, using the modified Bruce protocol. In 33% of patients an cardioverter-defibrillator (ICD) or cardiac resynchronization therapy device (CRT-D) was implanted during follow-up. Peak VO(2), percentage of predicted peak VO(2), VE/VCO(2) slope, OUES and POUE were analyzed. OUES was calculated using the formula VO(2) (l/min) = OUES (log(10)VE) + b. POUE was calculated as pVO(2) (l/min) / log(10)peakVE (l/min). Correlation coefficients between the studied parameters were obtained. The prognosis of each variable adjusted for age was evaluated through Cox proportional hazard models and R2 percent (R2%) and V index (V6) were used as measures of the predictive accuracy of events of each of these variables. Receiver operating characteristic (ROC) curves from logistic regression models were used to determine the cut-offs for OUES and POUE.
pVO(2): 20.5±5.9; percentage of predicted peak VO(2): 68.6±18.2; VE/VCO(2) slope: 30.6±8.3; OUES: 1.85±0.61; POUE: 0.88±0.27. During a mean follow-up of 33.1±14.8 months, 45 (21.8%) patients died, 10 (4.9%) underwent urgent heart transplantation and in three patients (1.5%) a left ventricular assist device was implanted. All variables proved to be independent predictors of this combined event; however, VE/VCO2 slope was most strongly associated with events (HR 11.14). In this population, POUE was associated with a higher risk of events than OUES (HR 9.61 vs. 7.01), and was also a better predictor of events (R2: 28.91 vs. 22.37).
POUE was more strongly associated with death, urgent heart transplantation and implantation of a left ventricular assist device and proved to be a better predictor of events than OUES. These results suggest that this new parameter can increase the prognostic value of CPET in patients with CHF.
越来越多的证据表明，摄氧效率斜率（OUES）具有预后价值，它是一种心肺运动试验（CPET）参数，源自慢性心力衰竭（CHF）患者氧气消耗（VO₂）与分钟通气量（VE）之间的对数关系。
评估一种新的CPET参数——峰值摄氧效率（POUE）的预后价值，并将其与CHF患者的OUES进行比较。
我们前瞻性地研究了206例因扩张型心肌病导致的稳定CHF连续患者——153例男性，年龄53.3±13.0岁，缺血性病因占35.4%，左心室射血分数27.7±8.0%，窦性心律占81.1%，97.1%接受ACE-Is或ARBs治疗，78.2%接受β受体阻滞剂治疗，60.2%接受螺内酯治疗——这些患者使用改良Bruce方案进行了首次症状限制的最大运动平板CPET。在33%的患者中，随访期间植入了心脏复律除颤器（ICD）或心脏再同步治疗设备（CRT-D）。分析了峰值VO₂、预测峰值VO₂百分比、VE/VCO₂斜率、OUES和POUE。OUES使用公式VO₂（l/min）= OUES（log₁₀VE）+ b计算。POUE计算为pVO₂（l/min）/ log₁₀峰值VE（l/min）。获得了研究参数之间的相关系数。通过Cox比例风险模型评估调整年龄后的每个变量的预后，并使用R²百分比（R2%）和V指数（V6）作为这些变量各自事件预测准确性的度量。使用逻辑回归模型的受试者工作特征（ROC）曲线来确定OUES和POUE的临界值。
pVO₂：20.5±5.9；预测峰值VO₂百分比：68.6±18.2；VE/VCO₂斜率：30.6±8.3；OUES：1.85±0.61；POUE：0.88±0.27。在平均33.1±14.8个月的随访期间，45例（21.8%）患者死亡，10例（4.9%）接受了紧急心脏移植，3例（1.5%）患者植入了左心室辅助装置。所有变量均被证明是这一联合事件的独立预测因素；然而，VE/VCO₂斜率与事件的相关性最强（HR 11.14）。在该人群中，POUE与事件风险的相关性高于OUES（HR 9.61对7.01），并且也是事件的更好预测指标（R²：28.91对22.37）。
POUE与死亡、紧急心脏移植和左心室辅助装置植入的相关性更强，并且被证明是比OUES更好的事件预测指标。这些结果表明，这个新参数可以提高CPET对CHF患者的预后价值。
