Disclosures: M.G. and C.G. have received compensation for scientific symposia from AOP Orphan Pharmaceuticals AG, Actelion, Servier, GlaxoSmithKline. M.G. is holding an educational grant from United Therapeutics Corporation (grant no. REG-NC-002) and C.G. is holding an educational grant from Bayer (grant no. 15662).R.N. has relationships with drug companies including AOP Orphan Pharmaceuticals, Actelion, Bayer, Reata, Lung Biotechnology Corporation, and United Therapeutics. In addition to being investigator in trials involving these companies, relationships include consultancy service, research grants, and membership of scientific advisory boards.I.M.L. has relationships with drug companies including AOP Orphan Pharmaceuticals, Actelion, Bayer-Schering, Astra-Zeneca, Servier, Cordis, Medtronic, GlaxoSmithKline, Novartis, Pfizer, and United Therapeutics. In addition to being investigator in trials involving these companies, relationships include consultancy service, research grants, and membership of scientific advisory boards.