Exercise Capacity and Quality of Life in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease with a high mortality rate that can be divided into different groups according to etiology and prognosis. Few studies have investigated differences in the exercise capacity and quality of life (QOL) among the different groups of PAH patients. Therefore, we aimed to (1) compare the hemodynamic exercise responses between patients with idiopathic pulmonary arterial hypertension (IPAH) and PAH associated with other diseases (APAH), and (2) determine the factors associated with exercise capacity in patients with PAH.

Six patients diagnosed with IPAH and eight with APAH [congenital heart disease (CHD)-dominant PAH] were included in this study. The main outcome measures included body composition, exercise capacity, hemodynamic measurements, physical activity levels, fatigue severity, and QOL.

The CHD-dominant PAH group had a significantly lower predicted peak oxygen consumption (VO_2pred %), pressure of end-tidal carbon dioxide at the peak and at anaerobic threshold (PETCO_2peak and PETCO_2@AT), and significantly elevated ventilatory equivalent (VE/VCO_2slope and VE/VCO_2@AT) compared with the IPAH group. Multiple regression analysis indicated that PETCO_2@AT was significantly associated with either VO_2peak (β = 0.805, adjusted R² = 0.619, p = 0.001) or 6-minute walk distance (β = 0.816, adjusted R² = 0.638, p < 0.001).

Patients with CHD-dominant PAH had poor exercise capacity and exercise responses compared to those with IPAH. Evaluating exercise capacity and the patient response to exercise using cardiopulmonary exercise testing is increasingly important in view of the etiology of PAH.