BACKGROUND Exercise pulmonary hypertension (ePH), defined as a mean pulmonary artery pressure (mPAP)/cardiac output (Qc) slope >3 WU during exercise, is common in patients with heart failure with preserved ejection fraction (HFpEF). However, the pulmonary gas exchange-related effects of an exaggerated ePH (EePH) response are not well-defined, especially in relation to dyspnea on exertion (DOE) and exercise intolerance. METHODS 48 HFpEF patients underwent invasive (pulmonary and radial artery catheters) constant-load (20W) and maximal incremental cycle testing. Hemodynamic measurements (mPAP and Qc), arterial blood and expired gases, and ratings of breathlessness (RPB, Borg 0-10) were obtained. The mPAP/Qc slope was calculated from rest-to-20W. Those with a mPAP/Qc slope >4.2 (median) were classified as HFpEF+EePH (n=24) and those with a mPAP/Qc slope <4.2 were classified as HFpEF (without EePH) (n=24). The A-aDO2, VD/VT (Bohr equation), and the VE/VCO2 slope (from rest-to-20W) were calculated. RESULTS PaO2 was lower (p=0.03), and VD/VT was higher (p=0.03) at peak exercise in HFpEF+EePH compared with HFpEF. A-aDO2 was similar at peak exercise between groups (p=0.14); however, HFpEF+EePH achieved the peak A-aDO2 at a lower peak work rate (p<0.01). The VE/VCO2 slope was higher in HFpEF+EePH compared with HFpEF (p=0.01). RPB was ≥1-unit higher at 20W and VO2peak was lower (p<0.01) in HFpEF+EePH compared with HFpEF. CONCLUSIONS These data suggest that EePH contributes to pulmonary gas exchange impairments during exercise by causing a V/Q mismatch that provokes both ventilatory inefficiency and hypoxemia, both of which seem to contribute to DOE and exercise intolerance in patients with HFpEF.

中文翻译：

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射血分数保留的心力衰竭患者与运动肺动脉高压相关的肺气体交换。


背景 运动性肺动脉高压 （ePH），定义为运动期间平均肺动脉压 （mPAP）/心输出量 （Qc） 斜率 >3 WU，常见于射血分数保留的心力衰竭 （HFpEF） 患者。然而，夸大的 ePH （EePH） 反应对肺气体交换相关的影响尚不明确，尤其是与劳力性呼吸困难 （DOE） 和运动不耐受有关。方法 48 例 HFpEF 患者接受了有创 （肺动脉和桡动脉导管） 恒定负荷 （20W） 和最大增量循环测试。获得血流动力学测量 （mPAP 和 Qc） 、动脉血和呼出气体以及呼吸困难评级 （RPB，Borg 0-10）。mPAP/Qc 斜率从静止到 20W 计算。mPAP/Qc 斜率 >4.2 （中位数） 的人群被归类为 HFpEF+EePH （n=24），mPAP/Qc 斜率 <4.2 的人群被归类为 HFpEF （无 EePH） （n=24）。计算 A-aDO2 、 VD/VT （玻尔方程） 和 VE/VCO2 斜率 （从静止到 20W）。结果 与 HFpEF 相比，HFpEF+EePH 在峰值运动时 PaO2 较低 （p=0.03），VD/VT 较高 （p=0.03）。A-aDO2 在组间运动高峰期相似 （p=0.14）;然而，HFpEF+EePH 在较低的峰工作速率 （p<0.01） 下达到 A-aDO2 峰。与 HFpEF 相比，HFpEF+EePH 的 VE/VCO2 斜率更高 （p=0.01）。与 HFpEF 相比，HFpEF+EePH 在 20W 时 RPB 高 ≥ 1 个单位，VO2peak 较低 （p<0.01）。结论 这些数据表明，EePH 通过导致 V/Q 不匹配而导致通气效率低下和低氧血症，从而导致运动期间的肺气体交换障碍，这两者都似乎会导致 HFpEF 患者的 DOE 和运动不耐受。