SF-36: 36-item short form questionnaire; IPAH: idiopathic pulmonary arterial hypertension; CTEPH: chronic thromboembolic pulmonary hypertension; PCS: physical component score; MCS: mental component score; CHD: congenital heart disease; APAH: associated pulmonary arterial hypertension; CTD: connective tissue disease; PAH: pulmonary arterial hypertension; BPA: balloon angioplasty; SF-12: 12-item short form questionnaire; CAMPHOR: Cambridge Pulmonary Hypertension Outcome Review; SGRQ: St George's Respiratory Questionnaire; HADS: Hospital Anxiety and Depression Scale; HPAH: hereditary pulmonary arterial hypertension. #: co-primary end-point.