A second conference in 1998 at Évian-les-Bains also addressed the causes of secondary PH ( i.e. those due to other medical conditions ) , and in 2008 , the 4th World Symposium on Pulmonary Arterial Hypertension was convened in Dana Point to modify the classification based on new understandings of disease mechanisms .
In 2003 , the 3rd World Symposium on Pulmonary Arterial Hypertension was convened in Venice to modify the classification based on the new understanding of disease mechanisms .