Use of balloon expandable stents in the palliative relief of obstructed right ventricular conduits

Objectives: The purpose of this study was to determine the efficacy of balloon expandable stents in the relief of obstructed conduits in the right heart, and to review both the immediate success and longevity of this palliation. Methods and results: Endovascular stents where placed in 17 children, median age 4.7 yrs (range 0.46-16.2 yrs), at a median of 1.6 yrs (range 0.33-6.7 yrs) after placement of conduits at surgery. A second stent was required in two children, either because of migration of the initial stent or residual proximal stenosis. Mean right ventricular to systemic pressure ratios were reduced from 0.77 +/- 0.24 to 0.50 +/- 0.13, and the minimum area of the pulmonary outflow tract increased from 24 +/- 12% to 69 +/- 26% of that expected for body surface area. Further surgery was needed in 8 patients following placement of the stent, in 5 within 10 months of implantation, due to inadequate relief of obstruction. Nonetheless, 3 of these a children achieved satisfactory palliation 18, 21 and 24 months prior to requiring insertion of a new conduit. Actuarial freedom from reoperation was 44% at 24 months. The remaining 3 children continue to benefit from the relief in obstruction provided by the stent at a mean interval from implantation of 24 +/- 8 months. In this group, the mean Doppler gradient across the right ventricular outflow tract was 35 +/- 13 mmHg (n=6). Conclusions: These early data indicate that endovascular stents are useful in the palliation of obstructed right ventricular conduits. In the short-term, the relief of obstruction achieved is well maintained, and has either delayed or obviated the need for insertion of new conduits.