Table 1.

Classification of pulmonary hypertension according to the World Symposium on Pulmonary Hypertension

Group	Definition
1	Pulmonary arterial hypertension
2	Pulmonary hypertension due to left heart disease
3	Pulmonary hypertension due to lung diseases and/or hypoxia
4	CTEPH
5	Pulmonary hypertension with unclear or multifactorial mechanisms