Table 1_Excess ventilation and chemosensitivity in patients with inefficient ventilation and chronic coronary syndrome or heart failure: a case–control study.docx

BackgroundIn patients with chronic coronary syndromes (CCS), increased ventilation/carbon dioxide production (V̇E/V̇CO2) slope has been found to predict disease progression and mortality, similarly to patients with heart failure (HF); however, increased chemosensitivity, a well-established predictor for mortality in patients with HF, has rarely been assessed in patients with CCS.
MethodPatients with CCS, HF with reduced ejection fraction (EF < 50%), healthy controls (45+ years), and young healthy adults (<35 years) were recruited. For patients, a V̇E/V̇CO2 slope ≥36 was an inclusion criterion. The Duffin rebreathing method was used to determine the resting end-expiratory partial pressure of carbon dioxide (PETCO2), ventilatory recruitment threshold (VRT), and slope (sensitivity) during a hyperoxic (150 mmHg O2) and hypoxic (50 mmHg O2) rebreathing test to determine the central and peripheral chemosensitivity.
ResultsIn patients with CCS, HF, controls, and young healthy adults, median V̇E/V̇CO2 slopes were 40.2, 41.3, 30.5, and 28.0, respectively. Both patient groups had similarly reduced hyperoxic VRT (at PETCO2 42.1 and 43.2 mmHg) compared to 46.0 and 48.8 mmHg in the control and young healthy adults. Neither hypoxic VRT nor hyper- or hypoxic slopes were significantly different in patients compared to controls. Both patient groups had lower resting PETCO2 than controls, but only patients with HF had increased breathing frequency and rapid shallow breathing at rest.
ConclusionIn patients with HF and/or CCS and excess ventilation, central chemoreflex VRT was reduced independently of the presence of HF. Low VRTs were related to resting excess ventilation in patients with CCS or HF; however, rapid shallow breathing at peak exercise was present only in patients with HF.
Clinical trial registration numberNCT05057884.

背景：在慢性冠状动脉综合征（chronic coronary syndromes, CCS）患者中，每分通气量/二氧化碳生成量斜率（V̇E/V̇CO2斜率）升高已被证实可预测疾病进展与死亡风险，这与射血分数降低型心力衰竭（heart failure with reduced ejection fraction, HF）患者的情况一致；然而，作为心力衰竭患者公认的死亡风险预测因子的化学敏感性升高，在慢性冠状动脉综合征患者中却极少被评估。
方法：本研究招募了慢性冠状动脉综合征患者、射血分数降低型心力衰竭患者（射血分数<50%）、健康对照者（年龄≥45岁）以及健康青年受试者（年龄<35岁）。针对慢性冠状动脉综合征患者，纳入标准为其V̇E/V̇CO2斜率≥36。本研究采用达芬重复呼吸法（Duffin rebreathing method），通过高氧（氧分压150 mmHg）与低氧（氧分压50 mmHg）重复呼吸试验，测定静息呼气末二氧化碳分压（PETCO2）、通气募集阈值（VRT）以及斜率（敏感性），以此评估中枢及外周化学敏感性。
结果：在慢性冠状动脉综合征患者、心力衰竭患者、健康对照者与健康青年受试者中，V̇E/V̇CO2斜率的中位数分别为40.2、41.3、30.5与28.0。与健康对照者（46.0 mmHg）及健康青年受试者（48.8 mmHg）相比，两个患者组的高氧通气募集阈值均显著降低（静息呼气末二氧化碳分压分别为42.1 mmHg与43.2 mmHg）。与健康对照者相比，两个患者组的低氧通气募集阈值、高氧或低氧斜率均无显著差异。两个患者组的静息呼气末二氧化碳分压均低于健康对照者，但仅心力衰竭患者存在静息呼吸频率升高与浅快呼吸表现。
结论：在合并通气过度的心力衰竭和/或慢性冠状动脉综合征患者中，中枢化学反射通气募集阈值（central chemoreflex VRT）的降低与心力衰竭的存在无关。慢性冠状动脉综合征或心力衰竭患者的低通气募集阈值与静息通气过度相关；然而，极量运动时的浅快呼吸仅见于心力衰竭患者。
临床试验注册号：NCT05057884。