Exercise limitations in various forms of pulmonary hypertension

Pulmonary hypertension (PH) is a progressive and life-threatening disorder that is characterized by a gradually progressive increase in the pulmonary vascular resistance resulting in an increase in pulmonary artery pressure. Most PH patients present with gradually progressive exercise intolerance, typically portrayed as exertional dyspnea, fatigue, palpitations and/or a non-productive cough. In PH, exercise is considered to be limited primarily by the inability of the right ventricle to sufficiently increase pulmonary blood flow, due to the increased pulmonary vascular resistance. A growing number of studies have shown that exercise testing provides diagnostic and prognostic information in PH patients. The most commonly used exercise tests in PH patients, are the cardio pulmonary exercise test (CPET) and the six minute walk test (6-MWT). In the studies described in this thesis we have focused on the mechanisms underlying exercise limitations in PH and on the use of exercise testing as parameter of outcome. Hereby, we mainly focused on chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary hypertension associated with congenital heart disease. Additionally, we assessed the contribution of PH in exercise limitations observed in sickle cell disease and patients idiopathic pulmonary fibrosis (IPF).