Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
Clinic of Thoracic and Occupational Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.
PLoS One. 2020 May 4;15(5):e0232693. doi: 10.1371/journal.pone.0232693. eCollection 2020.
In coronary artery disease (CAD), exercise intolerance with reduced oxygen uptake at peak exercise (VO2peak) is assumed to primarily reflect cardiovascular limitation. However, oxygen transport and utilization depends on an integrated organ response, to which the normal pulmonary system may influence overall capacity. This study aimed to investigate the associations between normal values of lung function measures and VO2peak in patients with exercise intolerance and CAD. We hypothesized that forced expiratory lung volume in one second (FEV1), transfer factor of the lung for carbon monoxide (TLCO) and TLCO/alveolar volume (TLCO/VA) above lower limits of normal (LLN) are associated with VO2peak in these patients. We assessed patients with established CAD (n = 93; 21 women) referred for evaluation due to exercise intolerance from primary care to a private specialist clinic in Norway. Lung function tests and cardiopulmonary exercise testing (CPET) were performed. Z-scores of FEV1, FEV1/forced vital capacity (FVC), TLCO and TLCO/VA were calculated using the Global Lung Function Initiative (GLI) software and LLN was defined as the fifth percentile (z = -1.645). Non-obstructive patients, defined by both FEV1 and FEV1/FVC above LLN, were assessed. The associations of FEV1Z-score, TLCOZ-score and TLCO/VAZ-score above LLN with VO2peak were investigated using linear regression models. Mean VO2peak ± standard deviation (SD) was 23.8 ± 6.4 ml/kg/min in men and 19.7 ± 4.4 ml/kg/min in women. On average, one SD increase in FEV1, TLCO and TLCO/VA were associated with 1.4 (95% CI 0.2, 2.6), 2.6 (95% CI 1.2, 4.0) and 1.3 (95% CI 0.2, 2.5) ml/kg/min higher VO2peak, respectively. In non-obstructive patients with exercise intolerance and CAD, FEV1, TLCO and TLCO/VA above LLN are positively associated with VO2peak. This may imply a clinically significant influence of normal lung function on exercise capacity in these patients.
在冠状动脉疾病 (CAD) 中，运动不耐受伴运动峰值时摄氧量 (VO2peak) 降低，通常被认为主要反映心血管受限。然而，氧气的输送和利用依赖于一个综合的器官反应，正常的肺部系统可能会影响整体能力。本研究旨在探讨肺功能测量的正常值与运动不耐受和 CAD 患者 VO2peak 之间的关系。我们假设一秒用力呼气容积 (FEV1)、一氧化碳肺转移因子 (TLCO) 和 TLCO/肺泡容积 (TLCO/VA) 高于正常值下限 (LLN) 与这些患者的 VO2peak 相关。我们评估了因运动不耐受而从初级保健机构转诊到挪威一家私人专科诊所的 93 名确诊 CAD 患者（21 名女性）。进行了肺功能测试和心肺运动测试 (CPET)。使用全球肺功能倡议 (GLI) 软件计算了 FEV1、FEV1/用力肺活量 (FVC)、TLCO 和 TLCO/VA 的 Z 分数，并将 LLN 定义为第 5 百分位数 (z = -1.645)。评估了非阻塞性患者，定义为 FEV1 和 FEV1/FVC 均高于 LLN。使用线性回归模型研究了 FEV1Z 分数、TLCOZ 分数和 TLCO/VAZ 分数高于 LLN 与 VO2peak 的关系。男性平均 VO2peak ± 标准差 (SD) 为 23.8 ± 6.4 ml/kg/min，女性为 19.7 ± 4.4 ml/kg/min。FEV1、TLCO 和 TLCO/VA 的平均 SD 增加 1 个单位，分别与 VO2peak 增加 1.4（95%CI 0.2，2.6）、2.6（95%CI 1.2，4.0）和 1.3（95%CI 0.2，2.5）ml/kg/min 相关。在运动不耐受和 CAD 的非阻塞性患者中，高于 LLN 的 FEV1、TLCO 和 TLCO/VA 与 VO2peak 呈正相关。这可能意味着正常肺功能对这些患者运动能力的临床显著影响。
