[A case of adult pulmonary supravalvular membranous stenosis which was successfully treated by percutaneous transluminal balloon dilatation].

We report a case of adult pulmonary supravalvular stenosis which was successfully treated with percutaneous transluminal balloon dilatation (PTBD). A 42-year-old man was admitted for a heart murmur and abnormal findings in the screening chest roentgenogram. Having no symptoms on admission, his physical activity was evaluated as Class I according to the classification of the New York Heart Association. A systolic murmur (Levine III/VI) with split second sound was audible at the left sternal border in the 3rd intercostal space. Chest roentgenogram revealed 57% of the cardio-thoracic ratio and no signs of increased pulmonary vascular markings. ECG showed incomplete right bundle branch block. Echocardiography and right ventriculography visualized the supravalvular membranous structured stenosed pulmonary artery 1cm above the pulmonic valve. Systolic pressure gradient between the right ventricle and the distal main pulmonary trunk was 54mmHg. The patient was diagnosed as having pulmonary supravalvular membranous stenosis. PTBD was applied using Inoue balloon catheter, where inflation was initiated from approximately 120% of pulmonary arterial diameter and terminated at 150%. This procedure decreased systolic pressure gradient from 54mmHg to 36mmHg without complication. After PTBD right ventriculography demonstrated that a part of the membranous structure had become floppy and movable. Pulmonary arterial diameter was unchanged. We considered that PTBD tore the membranous structure, which consequently resulted in the decrease of systolic pressure gradient. Systolic murmur diminished to Levine II/VI. Six months later, cardiac catheterization showed no change in systolic pressure gradient compared with that immediately after PTBD. This is the first report on pulmonary supravalvular membranous stenosis successfully treated with PTBD.(ABSTRACT TRUNCATED AT 250 WORDS)