AIMS Pulmonary hypertension (PH) and pulmonary vascular disease (PVD) are common and associated with adverse outcomes in left heart disease (LHD). This study sought to characterize the pathophysiology of PVD across the spectrum of PH in LHD. METHODS AND RESULTS Patients with PH-LHD [mean pulmonary artery (PA) pressure >20 mmHg and PA wedge pressure (PAWP) ≥15 mmHg] and controls free of PH or LHD underwent invasive haemodynamic exercise testing with simultaneous echocardiography, expired air and blood gas analysis, and lung ultrasound in a prospective study. Patients with PH-LHD were divided into isolated post-capillary PH (IpcPH) and PVD [combined post- and pre-capillary PH (CpcPH)] based upon pulmonary vascular resistance (PVR <3.0 or ≥3.0 WU). As compared with controls (n = 69) and IpcPH-LHD (n = 55), participants with CpcPH-LHD (n = 40) displayed poorer left atrial function and more severe right ventricular (RV) dysfunction at rest. With exercise, patients with CpcPH-LHD displayed similar PAWP to IpcPH-LHD, but more severe RV-PA uncoupling, greater ventricular interaction, and more severe impairments in cardiac output, O2 delivery, and peak O2 consumption. Despite higher PVR, participants with CpcPH developed more severe lung congestion compared with both IpcPH-LHD and controls, which was associated lower arterial O2 tension, reduced alveolar ventilation, decreased pulmonary O2 diffusion, and greater ventilation-perfusion mismatch. CONCLUSIONS Pulmonary vascular disease in LHD is associated with a distinct pathophysiologic signature marked by greater exercise-induced lung congestion, arterial hypoxaemia, RV-PA uncoupling, ventricular interdependence, and impairment in O2 delivery, impairing aerobic capacity. Further study is required to identify novel treatments targeting the pulmonary vasculature in PH-LHD.

中文翻译：

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左心病引起的肺动脉高压中的肺血管疾病：病理生理学影响。

目的 肺动脉高压 (PH) 和肺血管疾病 (PVD) 很常见，并且与左心疾病 (LHD) 的不良后果相关。本研究旨在描述 LHD PH 范围内 PVD ​​的病理生理学特征。方法和结果 PH-LHD 患者[平均肺动脉 (PA) 压力 >20 mmHg 且 PA 楔压 (PAWP) ≥15 mmHg] 和无 PH 或 LHD 的对照者接受侵入性血流动力学运动测试，同时进行超声心动图、呼出气体和血液检查前瞻性研究中的气体分析和肺部超声。根据肺血管阻力（PVR <3.0 或≥3.0 WU），PH-LHD 患者分为孤立性毛细血管后 PH (IpcPH) 和 PVD ​​[毛细血管后和前组合 PH (CpcPH)]。与对照组 (n = 69) 和 IpcPH-LHD (n = 55) 相比，CpcPH-LHD (n = 40) 参与者在休息时表现出较差的左心房功能和更严重的右心室 (RV) 功能障碍。通过运动，CpcPH-LHD 患者表现出与 IpcPH-LHD 相似的 PAWP，但 RV-PA 解偶联更严重，心室相互作用更大，心输出量、O2 输送和峰值 O2 消耗受损更严重。尽管 PVR 较高，但与 IpcPH-LHD 和对照组相比，CpcPH 参与者出现了更严重的肺充血，这与动脉氧张力较低、肺泡通气量减少、肺氧扩散减少以及通气-灌注不匹配程度更大有关。结论 LHD 中的肺血管疾病与独特的病理生理学特征相关，其特征是运动引起的肺充血加剧、动脉低氧血症、RV-PA 解偶联、心室相互依赖性以及 O2 输送受损，从而损害有氧能力。需要进一步研究来确定针对 PH-LHD 肺血管系统的新疗法。