Non-Invasive Measurement of Cardiac Output and Stroke Volume in PAH/CTEPH

This is a single center study to evaluate the use of non-invasive measurement of cardiac output and stroke volume to assess risk and response to treatment in patients with pulmonary arterial hypertension (PAH) and non- operable chronic thromboembolic pulmonary hypertension (CTEPH). We anticipate to enroll a total of 100 subjects at Ronald Reagan UCLA Medical Center. After informed consent is obtained, the following procedure will be performed: Patients with known or suspected pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) will undergo a right heart catheterization (RHC) as part of his or her standard of care. Three techniques of cardiac output (CO) measurement will be performed sequentially at the time of the RHC. The order of cardiac output testing will be randomized after informed consent is obtained and prior to the procedure. The operator performing the RHC procedure will be blinded to both the non-invasive blood pressure (NIBP) measurement and direct Fick cardiac output (CO) measurements while performing thermodilution cardiac output (CO) measurement. The device that will be used is the Edwards ClearSight system and EV1000 clinical platform, a device that measures non-invasive blood pressure (NIBP). Patients will be followed over the period of 1 year, up to every 3 months, to obtain serial measurements of six-minute walk distance (6MWD), World Health Organization (WHO)/New York Heart Association Functional Class (FC), and B-type natriuretic peptide (BNP) or N-terminal-pro hormone BNP (NT-proBNP) as part of standard of care. These serial measurements will be collected from the patient's medical record. Non-invasive hemodynamic measurements will be performed for research purposes. Additional visits will be scheduled to obtain the serial measurements one month prior and one month following if a patient is initiating or changing PH-specific therapy. As this is a study looking at the feasibility of non-invasive measurement of cardiac output and stroke volume for risk assessment and response to therapy in pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH), study personnel performing the study procedures will not be blinded to the clinical diagnosis and the management of the subject.