BALLOON ANGIOPLASTY FOR POSTOPERATIVE PULMONARY-ARTERY STENOSIS IN TRANSPOSITION OF THE GREAT-ARTERIES

Objectives. This study was designed to assess the success rate and determinants of success or failure of balloon angioplasty for postoperative pulmonary stenosis in patients with transposition of the great arteries. Background. Previous reports have suggested that pulmonary stenosis that develops after the arterial switch operation is not likely to be dilated. Methods. Twenty-eight patients with transposition of the great arteries underwent 39 balloon angioplasty procedures after the arterial switch operation. The mean age at dilation was 4.5 +/- 2.2 years (range 0.7 to 9.8), and the interval between operation and balloon dilation was 3.6 +/- 1.8 years. The criterion of successful dilation was a greater-than-or-equal-to 50% increase in predilation diameter or a greater-than-or-equal-to 50% decrease in predilation pressure gradient. If the right ventricular/aortic pressure ratio decreased by greater-than-or-equal-to 0.2, so that the ratio became <0.68, reoperation was thought to be not indicated. Results. The success rate of balloon angioplasty for pulmonary artery stenosis was 51% (20 of 39 dilations). The mean age at dilation in the group with successful dilation (3.6 years) was significantly younger than that in the group with unsuccessful dilation (5.4 years). The interval between operation and dilation in the successful dilation group (2.4 years) was significantly less than that in the unsuccessful dilation group (4.6 years). In 13 patients who underwent balloon angioplasty <3.5 years after operation, balloon dilation was successful in 92%. The balloon/artery ratio was significantly greater in the successful than in the unsuccessful dilation group. A right ventricular/aortic pressure ratio greater-than-or-equal-to 0.68 was observed in 20 patients, and reoperation was not indicated in 10 patients (50%). There was no death, but one pulmonary artery rupture that did not require surgical intervention occurred. Aneurysmal dilation of the pulmonary artery was observed in three patients. Conclusions. These data indicate that although the success rate of balloon angioplasty for pulmonary artery stenosis after the arterial switch operation is low (almost-equal-to 50%), balloon angioplasty can be the first therapeutic choice owing to the low complication rate and the potential benefit of the procedure. The success rate can be high if angioplasty is performed <3.5 years after operation and a balloon of adequate size is used.