Smoking: a Risk Factor for Pulmonary Arterial Hypertension?

Environmental factors may play a role in the genesis of pulmonary hypertension, especially in endothelial dysfunction. One widespread environmental factor associated with systemic endothelial dysfunction is cigarette smoke. It may well be that cigarette smoking is not only a risk factor for systemic but also for pulmonary vascular diseases and herewith may interact with other risk factors such as a genetic background and associated conditions. The existing studies which deal with this subject are only small single center case control studies providing less data. Therefore a large European multicenter study is necessary.

The investigators hypothesis are:

* a history of tobacco smoke exposure is highly prevalent in patients with PAH compared to the unaffected general population. * a history of tobacco smoke exposure is more prevalent in patients with PAH compared to CTEPH.