Use of intravascular stents in systemic venous and systemic venous baffle obstructions. Short-term follow-up results.

Background: Balloon-expandable intravascular stents are well accepted in the management of arterial obstructions. This study was undertaken to detail the immediate and short-term results of intravascular stent implantation in systemic venous and systemic venous baffle obstructions in children.
Methods and Results: Between September 1991 and June 1994, 12 patients had 21 stents implanted in 13 systemic venous obstructions, 1 patient having stents placed in 2 separate obstructions. In the baffle group, 4 of 13 obstructions were at the superior vena cava/right atrial junction after atrial baffling for transposition of the great arteries. One of 4 patients had complete obstruction requiring transseptal needle perforation before stent implantation. There was an immediate gradient reduction from 12 +/- 8.4 mm Hg (range, 4 to 20 mm Hg) to 1.3 +/- 1.9 mm Hg (range, 0 to 4 mm Hg, P = .05). The obstructed segment diameter increased from 3.5 +/- 3.9 mm (range, 0 to 8.5 mm) to 16 +/- 2.7 mm (range, 14 to 20 mm, P = .002). In the central vein group, 9 of 13 obstructions were in large central veins. Three of 9 patients had complete obstruction requiring transseptal needle perforation before stent implantation. There was an immediate gradient reduction from 10.3 +/- 8.5 mm Hg (range, 0 to 20 mm Hg) to 0.8 +/- 1.1 mm Hg (range, 0 to 3 mm Hg, P = .005). The obstructed segment diameter increased from 1.3 +/- 1.1 mm (range, 0 to 2.8 mm) to 9.4 +/- 1.7 mm (range, 7.6 to 12 mm, P < .001). There were no acute complications in either group. In the follow-up group, patients were scheduled for clinical follow-up at 3, 6, and 12 months with echocardiography or magnetic resonance imaging (MRI) at 3 or 6 months and for repeat cardiac catheterization at 12 months. All stents were patent by echocardiography or MRI when studied at follow-up. Cardiac catheterization in 6 of 12 patients, 2 to 13 months after stent, demonstrated that all stents remained patent without compression or fracture. Follow-up and immediate poststent gradients were not significantly different (1 +/- 1.6 versus 0.7 +/- 1.2 mm Hg, P = NS). Neointimal hyperplasia (5 of 6 patients) reduced the stent lumen only from 12.5 +/- 4.7 mm (range, 8 to 20 mm) to 10.6 +/- 4.7 mm (range, 4.5 to 17.7 mm, P = NS). No stents required redilation. One of 18 stents placed in series had "unlocked" and rotated in the venous lumen but remained fully patent to flow.
Conclusions: Balloon-expandable intravascular stents can be safely and effectively used to relieve systemic venous and systemic venous baffle obstructions, even when obstruction is complete. Short-term follow-up suggests excellent continued patency, but further follow-up is required to observe for progression of neointimal hyperplasia. We postulate that balloon-expandable intravascular stents will become the treatment of choice for the relief of selected systemic venous and venous baffle obstructions in the pediatric population.