 Pulmonary arterial hypertension PAH is a severe, chronic syndrome affecting the small pulmonary arteries blood vessels which carry blood from the heart to the lungs to pick up oxygen. At the time of the initiation of this study, no cure exists for this disease. Medtronic has developed a fully implantable, long term, intravenous infusion system, which has the potential to enhance patient convenience and ease of use, while reducing the opportunities for catheter-related infections and complication issues associated with currently used external delivery systems. The information gained from this study could provide evidence to support use on an implantable infusion system for the management of other disease states requiring chronic intravenous therapy. Additionally, information collected from this study may contribute to the design of new productstherapyies andor instructions for use. 