Sackler Faculty of Medicine, Cardiology Division, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
Sackler Faculty of Medicine, Cardiac Surgery Division, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
J Am Soc Echocardiogr. 2021 Feb;34(2):146-155.e5. doi: 10.1016/j.echo.2020.09.014. Epub 2020 Nov 11.
Current methods do not allow a thorough assessment of causes associated with limited exercise capacity in patients with chronic obstructive pulmonary disease (COPD).
Twenty patients with COPD and 20 matched control subjects were assessed using combined cardiopulmonary and stress echocardiographic testing. Various echocardiographic parameters (left ventricular [LV] volumes, right ventricular [RV] area, ejection fraction, stroke volume, S', and E/e' ratio) and ventilatory parameters (peak oxygen consumption [Vo] and A-Vo difference) were measured to evaluate LV and RV function, hemodynamics, and peripheral oxygen extraction (A-VO difference).
Significant differences (both between groups and for group-by-time interaction) were seen in exercise responses (LV volume, RV area, LV volume/RV area ratio, S', E/e' ratio, tricuspid regurgitation grade, heart rate, stroke volume, and Vo). The major mechanisms of reduced exercise tolerance in patients with COPD were bowing of the septum to the left in 12 (60%), abnormal increases in E/e' ratio in 12 (60%), abnormal stroke volume reserve in 16 (80%), low peak A-Vo difference in 10 (50%), chronotropic incompetence in 13 (65%), or a combination of several mechanisms. Patients with COPD and poor exercise tolerance showed attenuated increases in stroke volume, heart rate, and A-Vo difference and exaggerated changes in LV/RV ratio and LV compliance (ratio of LV volume to E/e' ratio) compared with patients with COPD with good exercise tolerance.
Combined cardiopulmonary and stress echocardiographic testing can be helpful in determining individual mechanisms of exercise intolerance in patients with COPD. In patients with COPD, exercise intolerance is predominantly the result of chronotropic incompetence, limited stroke volume reserve, exercise-induced elevation in left filling pressure, and peripheral factors and not simply obstructive lung function. Limited stroke volume is related to abnormal RV contractile reserve and reduced LV compliance introduced through septal flattening and direct ventricular interaction.
目前的方法无法全面评估慢性阻塞性肺疾病（COPD）患者运动耐力受限的相关原因。
对 20 例 COPD 患者和 20 例匹配的对照者进行心肺联合应激超声心动图检查。测量各种超声心动图参数（左心室[LV]容积、右心室[RV]面积、射血分数、每搏量、S'和 E/e'比值）和通气参数（峰值氧耗量[Vo]和 A-Vo 差），以评估 LV 和 RV 功能、血液动力学和外周氧摄取（A-VO 差）。
运动反应（LV 容积、RV 面积、LV 容积/RV 面积比值、S'、E/e'比值、三尖瓣反流分级、心率、每搏量、Vo）存在显著差异（组间和组内时间交互作用均有差异）。COPD 患者运动耐量降低的主要机制包括 12 例（60%）的室间隔向左弯曲、12 例（60%）的 E/e'比值异常升高、16 例（80%）的每搏量储备异常、10 例（50%）的峰值 A-Vo 差低、13 例（65%）的变时功能不全或几种机制的联合。与运动耐量良好的 COPD 患者相比，运动耐量差的 COPD 患者的每搏量、心率和 A-Vo 差增加幅度减弱，LV/RV 比值和 LV 顺应性（LV 容积与 E/e'比值之比）的变化更为明显。
心肺联合应激超声心动图检查有助于确定 COPD 患者运动不耐受的个体机制。在 COPD 患者中，运动不耐受主要是由于变时功能不全、每搏量储备有限、运动引起的左充盈压升高以及外周因素引起的，而不仅仅是阻塞性肺功能。LV 每搏量有限与 RV 收缩储备异常以及通过室间隔变平和直接心室相互作用引起的 LV 顺应性降低有关。
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