Pharmacogenomics in Pulmonary Arterial Hypertension

Our goal is to determine clinically in Pulmonary Arterial Hypertension patients if associations exist between the efficacy and toxicity of sitaxsentan, bosentan, and ambrisentan and several gene polymorphisms in several key disease-specific and therapy specific genes. Also characterized is the relationship between these polymorphisms and the severity of Pulmonary Arterial Hypertension using either baseline hemodynamic or clinical surrogates for disease severity. Hypothesis: Polymorphisms influence the efficacy and toxicity of specific Pulmonary Arterial Hypertension therapy as well as development/severity of PAH via their effect on PA remodeling, drug response, or metabolism. This study requires a one time 8.5 ml blood sample and clinical data to be obtained at initiation of therapy, 4 months after initiation of therapy and 12 months after initiation of therapy.