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

Objectives. This study was designed to assess the success rate and det erminants of success or failure of balloon angioplasty for postoperati ve pulmonary stenosis in patients with transposition of the great arte ries. Background. Previous reports have suggested that pulmonary steno sis 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 a rterial switch operation. The mean age at dilation was 4.5 +/- 2.2 yea rs (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 w as a greater-than-or-equal-to 50% increase in predilation diameter or a greater-than-or-equal-to 50% decrease in predilation pressure gradie nt. If the right ventricular/aortic pressure ratio decreased by greate r-than-or-equal-to 0.2, so that the ratio became <0.68, reoperation wa s thought to be not indicated. Results. The success rate of balloon an gioplasty for pulmonary artery stenosis was 51% (20 of 39 dilations). The mean age at dilation in the group with successful dilation (3.6 ye ars) was significantly younger than that in the group with unsuccessfu l 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 w ho underwent balloon angioplasty <3.5 years after operation, balloon d ilation was successful in 92%. The balloon/artery ratio was significan tly 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 1 0 patients (50%). There was no death, but one pulmonary artery rupture that did not require surgical intervention occurred. Aneurysmal dilat ion of the pulmonary artery was observed in three patients. Conclusion s. These data indicate that although the success rate of balloon angio plasty for pulmonary artery stenosis after the arterial switch operati on is low (almost-equal-to 50%), balloon angioplasty can be the first therapeutic choice owing to the low complication rate and the potentia l benefit of the procedure. The success rate can be high if angioplast y is performed <3.5 years after operation and a balloon of adequate si ze is used.