Chronic thromboembolic pulmonary hypertension [CTEPH] is a rare condition with a significant
risk of morbidity and mortality. The primary cause of CTEPH is thrombotic lesions, which did
not resolve after acute pulmonary embolism. This causes increased pulmonary vascular
resistance [PVR], leading to secondary remodeling of pulmonary arteries causing pulmonary
hypertension and ultimately progressive right heart failure. The treatment of choice is
surgical pulmonary endarterectomy [PEA], however up to 40% cases are not treated surgically,
due to operability, anatomic location of the lesions, patient choice and comorbidities
significantly increasing procedural risk. A new alternative procedure, balloon pulmonary
angioplasty [BPA] has been proposed for patients with inoperable CTEPH or persistent
pulmonary hypertension after pulmonary endarterectomy (PEA) and is currently characterized
with good outcome in functional capacity, hemodynamic parameters, biomarkers, and
health-related quality of life.
Exercise stress tests of the pulmonary circulation are used in workup and diagnosis of
pulmonary hypertension as a hemodynamic abnormality. The approach has allowed identification
of patients with normal or marginally increased mPAP at rest but with symptomatic increases
in mPAP at exercise, related to either increased resistance or increased left atrial
pressure. Although this differential diagnosis is of obvious therapeutic relevance,
guidelines about exercise stress studies of the pulmonary circulation have not been developed
until now for lack of robust evidence allowing for a consensus on clearly defined cutoff
values.
Neither the pathophysiology of the exercise limitation nor the underlying mechanisms of the
BPA - induced improvement were studied before. Therefore the aim of this study is to assess
the hemodynamic effects of BPA treatment on the pressure-flow relationship in the pulmonary
vasculature and the pulmonary vascular compliance. Furthermore, the investigators will
explore possible differences in treatment effect across centers. Especially explore the
timing of medical therapy vs balloon angioplasty.
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