<jats:p>Objectives: Pulmonary arterial dilatation is considered a consequence of chronic pulmonary hypertension (PH), but despite its relatively common detection, its prevalence and prognostic impact have not yet been systematically investigated. The aim of the study was to investigate these factors in a relatively large cohort of severe PH patients. Methods: One hundred and forty-one consecutive patients diagnosed with PH were monitored for a mean of 957 days. Data including functional class, exercise capacity, invasive hemodynamics and pulmonary artery (PA) echo/CT scan measurement were performed and outcomes prospectively collected. Results: PA dilatation is a common feature, present in the 76.6% of cases in this cohort of severe PH patients. Survival at 1, 2 and 3 years was 83, 71 and 58%, respectively. On univariate analysis, the baseline variables associated with a poor outcome were related to pulmonary arterial hypertension associated with connective tissue disease (CDT-PAH), New York Heart Association (NYHA) functional class, 6-min walk test and right atrial pressure. On multivariate analysis only CDT-PAH and NYHA functional class remained independently associated with poor survival. Conclusions: PA dilatation is commonly detected in severe PH patients and is not associated with an increased risk of death.</jats:p>