We present four cases of patients with a history of a pulmonary hypertension (PH), who had a component of lung disease disproportionate to the PH severity. Detailed evaluation revealed pulmonary arterial hypertension (PAH) and patients were qualified to the targeted pharmacotherapy, however the treatment did not bring the significant improvement of patients’ functional status. During follow-up, we observed deterioration of the clinical symptoms, that were not reflected in a significant progression of the right ventricle dysfunction.