Exercise physiology in pulmonary hypertension patients with and without congenital heart disease

BACKGROUND:
Cardiopulmonary exercise testing allows the assessment of integrative cardiopulmonary response to exercise.

AIMS:
The aim of the study was to better understand the exercise physiology in pulmonary arterial hypertension related to adult congenital heart disease compared to non-adult congenital heart disease patients by means of cardiopulmonary exercise testing parameters.

METHODS:
The present is a multicentre retrospective study which includes pulmonary hypertension group 1 and group 4 patients. All subjects underwent full clinical and instrumental evaluation, including cardiopulmonary exercise testing and right heart catheterization.

RESULTS:
One hundred and sixty-seven pulmonary hypertension patients (93 women and 74 men, 57 adult congenital heart disease and 110 non-adult congenital heart disease) were enrolled. Adult congenital heart disease patients had higher pulmonary pressure (mean pulmonary arterial pressure: 59.8 ± 19.5 mmHg vs 44.6 ± 16.5 mmHg, p < 0.001) and lower pulmonary blood flow (pulmonary blood flow: 3.3 (2.1-4.3) l/min vs 4.5 (3.8-5.4) l/min, p < 0.001). At cardiopulmonary exercise testing they had lower peak oxygen uptake/kg (12.8 ± 3.8 ml/kg/min vs 15.5 ± 4.2 ml/kg/min, p < 0.001) and higher ventilation/carbon dioxide elimination slope (53.2 (43.3-64.8) vs 44.0 (34.6-51.6), p < 0.001). When patients were paired for gender and peak oxygen uptake ( ± 1 ml/kg/min), obtaining 44 pairs, adult congenital heart disease patients had higher pulmonary pressure (mean pulmonary arterial pressure: 58.4 ± 20.2 mmHg vs 42.8 ± 16.8 mmHg, p < 0.001) and ventilation/carbon dioxide elimination slope (51.2 (43.4-63.6) vs 44.9 (35.4-55.1), p = 0.033).

CONCLUSIONS:
In pulmonary arterial hypertension-adult congenital heart disease patients, pulmonary pressure and ventilation/carbon dioxide elimination slope are higher compared to non-adult congenital heart disease pulmonary hypertension patients, while pulmonary blood flow and peak oxygen uptake are lower. After matching patients for gender and peak oxygen uptake, pulmonary pressure and ventilation/carbon dioxide elimination remain higher in adult congenital heart disease patients suggesting that the long-term adaptation to high pulmonary pressure, hypoxia and low pulmonary blood flow, as well as a persisting shunt has, at least partially, preserved exercise performance of pulmonary arterial hypertension-adult congenital heart disease patients.

背景：
心肺运动试验（Cardiopulmonary Exercise Testing）可用于评估机体运动时的整合性心肺应答反应。

研究目的：
本研究旨在借助心肺运动试验参数，对比成人先天性心脏病相关性肺动脉高压患者与非成人先天性心脏病肺动脉高压患者的运动生理学特征，以深化对该领域的认知。

研究方法：
本研究为多中心回顾性研究，纳入第1组及第4组肺动脉高压患者。所有受试者均接受全面的临床与器械检查，包括心肺运动试验及右心导管检查（right heart catheterization）。

研究结果：
共纳入167例肺动脉高压患者，其中女性93例、男性74例，成人先天性心脏病患者57例，非成人先天性心脏病患者110例。成人先天性心脏病患者的肺动脉压力更高（平均肺动脉压（mean pulmonary arterial pressure）：59.8±19.5 mmHg vs 44.6±16.5 mmHg，p<0.001），肺血流量（pulmonary blood flow）更低（3.3（2.1~4.3）L/min vs 4.5（3.8~5.4）L/min，p<0.001）。在心肺运动试验中，成人先天性心脏病患者的峰值摄氧量/kg（peak oxygen uptake/kg）更低（12.8±3.8 ml·kg⁻¹·min⁻¹ vs 15.5±4.2 ml·kg⁻¹·min⁻¹，p<0.001），通气/二氧化碳清除斜率（ventilation/carbon dioxide elimination slope）更高（53.2（43.3~64.8）vs 44.0（34.6~51.6），p<0.001）。当按照性别与峰值摄氧量（±1 ml·kg⁻¹·min⁻¹）进行1:1匹配后，共得到44对匹配患者。成人先天性心脏病患者的肺动脉压力仍更高（平均肺动脉压：58.4±20.2 mmHg vs 42.8±16.8 mmHg，p<0.001），通气/二氧化碳清除斜率也更高（51.2（43.4~63.6）vs 44.9（35.4~55.1），p=0.033）。

结论：
与非成人先天性心脏病肺动脉高压患者相比，成人先天性心脏病相关性肺动脉高压患者的肺动脉压力及通气/二氧化碳清除斜率更高，而肺血流量与峰值摄氧量更低。在按照性别与峰值摄氧量匹配患者后，成人先天性心脏病患者的肺动脉压力与通气/二氧化碳清除斜率仍维持较高水平，这提示长期适应高肺动脉压、缺氧及低肺血流量状态，加之持续存在的分流，至少在一定程度上保留了成人先天性心脏病相关性肺动脉高压患者的运动耐力。