The dysplastic pulmonary valve: echocardiographic features and results of balloon dilatation

The feasibility of using balloon dilatation to relieve stenosis caused by dysplasia of the pulmonary valve was assessed in seven patients (five female, mean age two years) with angiographically confirmed dysplasia who were identified among 38 patients with pulmonary valve stenosis selected for balloon dilatation over a two year period. The clinical features in three patients were consistent with Noonan's syndrome. In all patients the gradient across the valve was assessed by cross sectional echocardiography and Doppler echocardiography before cardiac catheterisation. Balloon dilatation was performed by conventional techniques. In one patient, who had balloon dilatation in the operating room before surgical valvectomy, the diameter of the valve orifice increased from 3 mm to 10 mm. Inspection showed a tear along the anterior commissure. The mean (SD) pressure gradients between the right ventricle and pulmonary artery before and immediately after dilatation in five patients were not significantly different (58 (28) and 47 (12) mm Hg) respectively. There was no overall significant change in the degree of stenosis when four of these patients were examined by Doppler echocardiography six months after operation (44 (17) mm Hg), although one patient (case 5) did show a significant reduction in gradient. This patient had angiographic and echocardiographic features of dysplasia and commissural fusion. Several echographic features were common to all patients and distinguished them from cases of typical pulmonary valve stenosis. These were: pronounced thickening of leaflets; leaflet immobility in diastole and systole; no dilatation of the sinuses of Valsalva in diastole, and supra-annular narrowing. These poor results of balloon dilatation suggest that commissural fusion is not an important mechanism for causing stenosis in the dysplastic pulmonary valve. When dysplasia of the pulmonary valve is identified clinically and echocardiographically, balloon dilatation is unlikely to improve haemodynamic function; it should be attempted if commissural fusion is present.