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

Abstract

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. 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. 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.