The OBJECTIVE was to study the prevalence and nature of congenital and acquired anatomical features of the pulmonary vascular bed in patients with single ventricle and to evaluate their impact on staged hemodynamic correction.METHODS AND MATERIALS. The study was a retrospective cohort study based on the study of the experience of surgical treatment of patients with a single ventricle from 2005 to 2022. 208 patients, 95 females and 113 males met the inclusion criteria. Depending on the type of the first stage of correction, all patients were divided into three groups: 1 – patients after the Norwood operation (n=84), 2 – patients after the isolated systemic-to-pulmonary shunts (n=74), 3 – patients after pulmonary artery band or those who did not need the first stage of surgical treatment (n=50).RESULTS. From all patients who survived the Stage-I (158 patients), 47 (30 %) patients underwent 72 reconstructive interventions on the pulmonary arteries: 8 % – before Stage-II, 46 % – at Stage-II, 17 % – between stages II and III, 11 % – at Stage-III and 18 % – after Stage-III. When comparing freedom from stenosis of the pulmonary arteries, statistically significant differences were found between groups of patients (p=0.005), with the least freedom from stenosis in group 1 (after the Norwood operation) and the greatest freedom from stenosis in group 3 (after pulmonary artery band or without first stage of correction).CONCLUSIONS. Patients with a functionally single ventricle are at risk of developing pulmonary artery stenosis throughout the entire period of staged hemodynamic correction and after its completion. The identified narrowing needs immediate correction, since a long-term existing narrowing can lead to hypoplasia of the pulmonary vascular bed and become an obstacle to the timely Fontan completion. More extensive use of tomographic imaging techniques is recommended in order to fully assess the degree of narrowing.