 There is also a Catheter Imaging Sub-Study that is being done to measure the shape change of the Model 10642 Implantable Intravascular Catheter during a given set of patient positions through the use of x-ray imaging. This data will help us develop more clinically realistic bench tests and simulations that better mimic the challenges experienced by an implanted catheter. This Catheter Imaging Sub-Study will be conducted at up to seven centers and will enroll up to forty patients that are currently enrolled in the DelIVery for PAH clinical study and are at least three months post-implant of their current catheter and pump. 