Surgical treatment of subaortic stenosis after biventricular repair of double-outlet right ventricle.

Out of 180 patients who underwent biventricular repair of double-outlet right ventricle between 1980 and 1995, 9 (5%) required reoperation because of subaortic stenosis. Two other patients who initially underwent operation elsewhere underwent reoperation at our institution because of subaortic stenosis. The median age at biventricular repair was 4 months. Repair consisted of tunnel construction from the left ventricle to the aorta in nine patients; the remaining two patients received an arterial switch operation with ventricular septal defect closure. Subaortic stenosis developed with time: the mean postoperative left ventricle-to-aorta gradient after repair was 10 +/- 19 mm Hg (range, 0 to 50 mm Hg) and became 84 +/- 27 mm Hg (range, 40 to 124 mm Hg) in a mean delay of 45 +/- 66 months (range, 1 to 213 months). At reoperation, the obstruction was caused by the protrusion of the inferior rim of the ventricular septal defect into the left ventricular outflow tract associated with subaortic hypertrophied muscle and membrane. The 11 patients underwent 15 reoperations. Surgical technique consisted of an extended septoplasty in 6 reoperations. In this technique an incision was made in the septal patch and was extended into the muscle toward the apex until a large opening of the left ventricular outflow pathway was obtained. A new patch was then secured to streamline the left ventricular outflow tract. None of the patients who underwent extended septoplasty had to undergo reoperation. There were no early or late deaths. At 115 +/- 85 months after biventricular repair, all patients were in New York Heart Association functional class I or II and the mean postoperative left ventricle-to-aorta gradient was 20 +/- 24 mm Hg (range, 0 to 60 mm Hg). We conclude that after biventricular repair of double-outlet right ventricle, the subaortic region is at risk for the development of stenosis. Surgical treatment adapted to the anatomy of the obstruction can offer good early and midterm results. It seems that an aggressive approach by an extended septoplasty avoids multiple reoperations.