Correlation Between Estimated Right Atrial Pressure and BNP in Pulmonary HTN (CRAB-PH)

Pulmonary hypertension patients who choose to participate: Written informed consent will be obtained for the study. Patients must sign the informed consent before participating in any study related procedures. * All inclusion and exclusion criteria will be reviewed. * Demographic history will be recorded. * Vital signs will be performed. * A medication history will be taken. * A smoking history will be recorded. * BNP levels will be measured as a part of usual care at PH visits. * Ultrasonographic measurements will be performed at the clinic visit. * Ultrasonographic measurements: IVC Measurements * Performed in the subcostal view in supine position. * Images will be captured in a video format. * Maximal IVC diameter 1 to 2 cm from the junction of the right atrium and the IVC at end-expiration just proximal to the junction of the hepatic veins. The IVC collapsibility index to give an estimate of RAP. * Inspiratory collapse of \> 50% or \< 50% will be ascertained based on the measurements. Jugular Vein Measurements * Patient will be placed in 45° position * Longitudinal images will be obtained of the right jugular vein. * Location of tapering of the jugular vein is measured, and distance from the sternal angle is recorded as ultrasound-measured jugular venous pressure (JVP). Clinical Worsening Outcomes • At each visit during year 1, and then every 6 months for years 2-3, clinical worsening events will be captured. These events are defined as: * Death * PH-related hospitalization * Lung transplant * Atrial septostomy * Functional Class worsening and step up in therapy Study Timing * Enrollment of patients for a period of 1 year. Subsequently, no more patients will be enrolled. Patients who are enrolled will be followed clinically without further study-related testing at their regular clinic visits after completion of year 1. * All patients enrolled will have ultrasonographic measurements of IVC and jugular veins at each clinic visit for 1 year. * Data collection regarding meeting clinical worsening end points and BNP levels will be collected at the regular clinic visits at year 2 and 3 of the study. * If patients are lost to follow up at clinics (including year-1), telephone correspondence, social security database review or chart review at 6-month intervals will be performed to determine vital status and see if they have met any clinical worsening endpoints. * Study will close after the final patient has completed 3-years of follow up.