Hemodynamic Evaluation and Morphological Changes of Right Ventricular Out-flow Tract and Pulmonary Valve after Balloon Pulmonary Valvuloplasty

Balloon pulmonary valvuloplasty (BPV) was attempted in 38 cases of congenital pulmonary valve stenosis. It was effective and was done without complication in 36 cases, however it was not effective in two cases of pulmonary valve dysplasia. The balloon used was 20-50% larger in diameter than the pulmonary valve annulus. In the seven cases in which the transvalvular pressure gradient was above 100 mmHg on cardiac catheterization, right ventriculography demonstrated that the functional obstruction of the right ventricular outflow tract increased immediately after BPV, however it subsequently improved at one year after the procedure. At between one and three months after BPV, two-dimensional echocardiography demonstrated that the morphological obstruction to the right ventricular outflow tract had diminished. In two cases, localized right ventricular septal hypertrophy with severe pulmonary valve stenosis was observed by two-dimensional echocardiography and right ventriculography, and persisted at one year. In all cases, two-dimensional echocardiography and angiography demonstrated doming pulmonary valves with valve stenosis, which was diminished by BPV. The pulmonary valve morphology was observed by two-dimensional echocardiography in three cases following BPV. In one case, partial relief of pulmonary valve obstruction was seen to be due to commissural splitting and in the other two, to tearing of cusp tissue. Inspection of the pulmonary valve at operation was made in one case who underwent elective surgery for repair of an atrial septal defect which was associated with pulmonary valve stenosis. It demonstrated partial relief of pulmonary valve stenosis by tearing of cusp tissue. In conclusion, BPV is as effective a treatment for congenital pulmonary valve stenosis as open valvulotomy. In our follow-up study, it has shown no apparent complications. The transient obstruction in the right ventricular outflow tract immediately after BPV improved within one month and improved further after three months and one year. However, in the more long-standing cases the localized right ven tricular septal hypertrophy persisted and these cases will require, a long term follow-up.