Group 4 pulmonary hypertension (PH) includes several conditions associated with obstructions in the pulmonary arterial tree. Chronic thromboembolic PH (CTEPH), the most common type of group 4 PH in adults, has attracted the most attention to date. In this condition, the rise in pulmonary artery pressure results from a combination of the obstruction to flow caused by organised thrombus and pulmonary arterial hypertension (PAH)-like microvascular disease, which develops as a result of excessive blood flow and shear stress in unobstructed areas of the lung. For this reason, CTEPH is typically managed both through mechanical relief of the obstruction (pulmonary endarterectomy and/or balloon pulmonary angioplasty; BPA) and PAH therapies. International guidelines have only relatively recently recognised conditions other than CTEPH that may cause PH associated with pulmonary artery obstruction [1, 2]: congenital pulmonary arterial stenosis has been classified under subgroup 4.2. However, there is still limited understanding about the prevalence, pathophysiology and prognosis of peripheral pulmonary artery stenosis in adults.