Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University.
Clinical Research and Medical Innovation Center, Hokkaido University Hospital.
Circ J. 2018 Oct 25;82(11):2753-2760. doi: 10.1253/circj.CJ-18-0103. Epub 2018 Aug 31.
Oxygen uptake (V̇O) at peak workload and anaerobic threshold (AT) workload are often used for grading heart failure (HF) severity and predicting all-cause mortality. The clinical relevance of respiratory exchange ratio (RER) during exercise, however, is unknown.
We retrospectively studied 295 HF patients (57±15 years, NYHA class I-III) who underwent cardiopulmonary exercise testing. RER was measured at rest; at AT workload; and at peak workload. Peak V̇O had an inverse correlation with RER at AT workload (r=-0.256), but not at rest (r=-0.084) or at peak workload (r=0.090). Using median RER at AT workload, we divided the patients into high RER (≥0.97) and low RER (<0.97) groups. Patients with high RER at AT workload were characterized by older age, lower body mass index, anemia, and advanced NYHA class. After propensity score matching, peak V̇O tended to be lower in the high-RER than in the low-RER group (14.9±4.5 vs. 16.1±5.0 mL/kg/min, P=0.06). On Kaplan-Meier analysis, HF patients with a high RER at AT workload had significantly worse clinical outcomes, including all-cause mortality and rate of readmission due to HF worsening over 3 years (29% vs. 15%, P=0.01).
High RER during submaximal exercise, particularly at AT workload, is associated with poor clinical outcome in HF patients.
峰值工作负荷时的摄氧量（V̇O）和无氧阈（AT）工作负荷常被用于心力衰竭（HF）严重程度分级和全因死亡率预测。然而，运动期间呼吸交换率（RER）的临床意义尚不清楚。
我们回顾性研究了 295 例 HF 患者（57±15 岁，NYHA Ⅰ-Ⅲ级），这些患者均接受了心肺运动测试。在休息时、AT 工作负荷时和峰值工作负荷时测量 RER。峰值 V̇O 与 AT 工作负荷时的 RER 呈负相关（r=-0.256），但与休息时（r=-0.084）或峰值工作负荷时（r=0.090）无相关性。我们使用 AT 工作负荷时的 RER 中位数，将患者分为高 RER（≥0.97）和低 RER（<0.97）组。AT 工作负荷时 RER 较高的患者年龄较大、体重指数较低、贫血和 NYHA 分级较高。经过倾向评分匹配后，高 RER 组的峰值 V̇O 较低 RER 组有所降低（14.9±4.5 vs. 16.1±5.0 mL/kg/min，P=0.06）。Kaplan-Meier 分析显示，AT 工作负荷时 RER 较高的 HF 患者临床结局较差，包括全因死亡率和因 HF 恶化而在 3 年内再次住院的发生率（29% vs. 15%，P=0.01）。
HF 患者亚极量运动时（尤其是 AT 工作负荷时）的高 RER 与较差的临床结局相关。
