Initial Use of Ambrisentan plus Tadalafil in Pulmonary Arterial Hypertension

University Hospital Heidelberg, Université Paris-Sud, Heidelberg University, Universities of Giessen and Marburg Lung Center, University of Bologna, Universitat de Barcelona, Medical Research Network, Baylor College of Medicine, Gilead Sciences (United States), Michigan Medicine, Assistance Publique – Hôpitaux de Paris, Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique, Inserm, Centre Chirurgical Marie Lannelongue, Erasmus Hospital, Harbor–UCLA Medical Center, The Lundquist Institute, University Hospital and Clinics, University Medical Center, Amsterdam UMC Location VUmc, University of Rochester, GlaxoSmithKline (United Kingdom), University of California, San Diego