title: Early and intermediate-term complications of self-expanding stents limit its potential application in children with congenital heart disease.
abstract: OBJECTIVE
  We report on the early and intermediate-term follow-up results of self-expanding Wallstent (Schneider, Switzerland) implanted in children with 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 Wallstents between December 1993 and June 1997 in two institutions. The mean age and weight were 10.8+/-4.5 years and 30.5+/-14.2 kg, respectively. The 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 recatheterization at a median of 5.8 months (range 0.5 to 31, mean 8.1 months) after stenting. Hemodynamic and angiographic changes after the interventional 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 pressure 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 narrowest 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 mm Hg (82% decrease, p = 0.04) across the stented venous channel. Distal migration of two optimally positioned stents occurred within 24 h of implantation. At recatheterization, significant neointimal ingrowth (>30% of the expanded diameter) was noted in 7 (28%) of the 25 implanted stents. This responded poorly to balloon dilation. Predisposing factors for the neointimal ingrowth 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 migration, significant neointimal ingrowth and its unyielding design to overdilation limit its application to this patient group.
authors.affiliation: Grantham Hospital, Department of Pediatrics, University of Hong Kong, Aberdeen.
authors.forename: Y F
authors.initials: YF
authors.lastname: Cheung
authors.forename: S
authors.initials: S
authors.lastname: Sanatani
authors.forename: M P
authors.initials: MP
authors.lastname: Leung
authors.forename: D G
authors.initials: DG
authors.lastname: Human
authors.forename: A K
authors.initials: AK
authors.lastname: Chau
authors.forename: J A
authors.initials: JA
authors.lastname: Culham
mesh_terms: D000293:Adolescent; D000792:Angiography; D000800:Angioplasty, Balloon / Q000295:instrumentation*; D002648:Child; D002675:Child, Preschool; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000628:therapy; D019544:Equipment Failure Analysis; D005260:Female; D005500:Follow-Up Studies; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000628:therapy*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D011651:Pulmonary Artery / Q000002:abnormalities / Q000000981:diagnostic imaging; D011668:Pulmonary Veno-Occlusive Disease / Q000000981:diagnostic imaging / Q000628:therapy; D019233:Retreatment; D015607:Stents; D016896:Treatment Outcome