Early and intermediate-term complications of self-expanding stents limit its potential application in children with congenital heart disease

OBJECTIVES We report on the early and intermediate-term follow-up results o f self-expanding Wallstent (Schneider, Switzerland) implanted in children w ith congenital heart disease. BACKGROUND The inherent shortcomings of balloon-expandable stents prompted the trial of an alternative stent. METHODS Twenty patients underwent 22 implantations of 25 self-expanding Wal lstents between December 1993 and June 1997 in two institutions. The mean a ge and weight were 10.8 +/- 4.5 years and 30.5 +/- 14.2 kg, respectively. T he patients were divided into two groups: 1) Group I comprised 17 patients with pulmonary arterial stenoses, 2) Group II comprised four patients with venous stenoses (one belonged to both groups). Sixteen patients underwent r ecatheterization at a median of 5.8 months (range 0.5 to 31, mean 8.1 month s) after stenting. Hemodynamic and angiographic changes after the intervent ional procedures and complications were documented. RESULTS All the stents were successfully deployed in the intended position. In Group I, the narrowest diameter of the stented vessel increased from 4. 1 +/- 1.5 to 8 +/- 2 mm (95% increase, p < 0.0001) while the systolic press ure gradient across decreased from 24.6 +/- 15.8 to 12.1 +/- 11.4 mm Hg (51 % decrease, p = 0.001). In Group II, the dimensional changes of the narrowe st segment increased from 4.3 +/- 0.5 to 7.5 +/- 0.4 mm (75% increase, p = 0.003), and the pressure gradient reduced from 5.0 +/- 2.9 to 0.9 +/- 1.0 m m Hg (82% decrease, p = 0.04) across the stented venous channel. Distal mig ration of two optimally positioned stents occurred within 24 h of implantat ion. At recatheterization, significant neointimal ingrowth (>30% of the exp anded diameter) was noted in 7 (28%) of the 25 implanted stents. This respo nded poorly to balloon dilation. Predisposing factors for the neointimal in growth included stents of smaller diameter (<9 mm) and longer period after implantation. CONCLUSIONS Self-expanding Wallstent could be deployed easily and safely to relieve vascular stenoses in children. The complications of distal migrati on, significant neointimal ingrowth and its unyielding design to overdilati on limit its application to this patient group. (C) 2000 by the American Co llege of Cardiology.