The keys to diagnosis are a detailed history and thorough clinical examination of the patient. The affected person should be transferred to a specialist centre for clarification. Only those patients in whom the risk of developing PH is substantially raised should undergo screening. This includes patients with a known BMPR II mutation, scleroderma and patients with portal hypertension who are being assessed for a liver transplant.
International specialist associations differentiate between 4 diagnostic steps: suspicion, detection, categorisation in the Dana Point classification system, evaluation of the severity. Functional classification is undertaken on the basis of NYHA Classes I-IV (Table 2). Patients in NYHA classes I or II at the time of diagnosis have a mean survival of 6 years in comparison with a mean survival of 2.5 years and 6 months respectively in NYHA classes III and IV where the disease is already at an advanced stage. Another option for assessing severity is provided by the 6-minute walk test (6-minute walk distance, 6MWD), in which the distance covered by a patient in 6 minutes is measured. The 6MWD has good prognostic value and is therefore used as a primary endpoint in many studies. It also constitutes a good parameter for progress during treatment. The maximum oxygen uptake (peak VO2) measured during a bicycle ergometer test is also an independent predictor of mortality .