The article discusses the appraisal of the degree of pulmonary hypertension and surgery of a ventricular septal defect with pulmonary hypertension in 108 patients whose ages ranged from 8 months to 31 years. The hemodynamic and morphological manifestations of pulmonary hypertension were found to increase with age. The hemodynamic manifestations of the anomaly may be similar in different types of changes of the vascular wall. A sharply hypertrophied middle muscular coat may be the cause of residual high pressure after closure of the defect, but with gradual reduction in contrast to the stable increase in sclerosis of the vascular lumen. This predetermines lung biopsy as an obligatory method for verifying the severity of pulmonary hypertension, which together with the hemodynamic data allows the indications for closure of the ventricular septal defect to be determined.