Noninvasive Determination of Cerebral Tissue Oxygenation in Pulmonary Hypertension

To study the effect of acute pulmonary vasodilatation on cerebral tissue oxygenation (CTO) and cerebral blood flow (CBF) as indicator for cerebrovascular autoregulation in comparison to the effects of supplemental oxygen, decreased carbon dioxide by hyperventilation and exercise in patients with pulmonary hypertension (PH) undergoing clinically indicated right heart catheterisation (RHC). Oxygenation and hemodynamic parameters will be assessed during RHC according to standard procedures. Non-invasive near infrared spectroscopy (NIRS) and a nasal canula will be additionally applied to measure CTO, CBF and endtidal CO2 (EtCO2). All parameters will be obtained at rest breathing room air, during an oxygen challenge, during standardized hyperventilation, under vasodilatation testing and during exercise in random, single-blinded sequences (except for exercise and hyperventilation). Pulmonary, systemic and cerebral oxygenation parameters and hemodynamics will be correlated with each other and functional class, quality of life, exercise and cognitive assessments at the time of the RHC and after three month.