title: Percutaneous stent implantation to stenotic bioprosthetic valves in the pulmonary position.
abstract: BACKGROUND
  We evaluated stent implantation across stenotic bioprosthetic pulmonary valves in 9 patients.
  
  
  METHODS
  Nine patients (6 male patients) underwent stent implantation across stenotic bioprosthetic pulmonary valves between July 1996 and July 1999 at the Hospital for Sick Children, Toronto. Catheter intervention was indicated if echocardiography revealed Doppler estimates of right ventricular pressure of more than two thirds of systemic arterial pressure (or systolic septal flattening with an estimated gradient of >60 mm Hg across the valve prosthesis). Catheterization was performed during general anesthesia at an age (mean +/- SD) of 9.3 +/- 3.5 years and a weight of 32.0 +/- 17.1 kg 5.9 +/- 1.8 years after surgical insertion of a bioprosthetic valve in the pulmonary position: 7 patients with tetralogy of Fallot, 1 patient with congenital pulmonary stenosis-insufficiency, and 1 patient after a Rastelli operation. All had systolic septal flattening and right ventricular dilatation with moderate-to-severe pulmonary insufficiency before intervention. Fluoroscopy times were 33.1 +/- 9.5 minutes. Seven patients received a single P4014 stent, and 2 received single P308 stents (Palmaz; Johnson & Johnson Interventional Systems, Warren, NJ) without significant complications.
  
  
  RESULTS
  The right ventricular systemic pressure decreased acutely from 83% +/- 16% to 41% +/- 10% (P <.001, n = 9), and the transvalvular gradient decreased from 49.7 +/- 8.5 to 11.0 +/- 5.9 mm Hg (P <.001, n = 8). During the follow-up period (10.9 +/- 8.1 months, n = 8), 1 patient had an unsuccessful attempt at redilation of the stent (right ventricular pressure, 60% systemic) and underwent uneventful surgical pulmonary valve replacement. None of the remaining patients had echocardiographic evidence of systolic septal flattening, and right ventricular dimensions did not change significantly.
  
  
  CONCLUSIONS
  Stent implantation is a safe and effective means of providing palliative relief of obstructed bioprosthetic valves in the pulmonary position and can safely delay the requirement for pulmonary valve replacement.
authors.affiliation: Department of Pediatrics and Surgery, Division of Cardiology, The Variety Club Catheterization Laboratories, The Hospital for Sick Children, The University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Carlos A C
authors.initials: CA
authors.lastname: Pedra
authors.forename: Henri
authors.initials: H
authors.lastname: Justino
authors.forename: David G
authors.initials: DG
authors.lastname: Nykanen
authors.forename: Glen
authors.initials: G
authors.lastname: VanArsdell
authors.forename: John G
authors.initials: JG
authors.lastname: Coles
authors.forename: William G
authors.initials: WG
authors.lastname: Williams
authors.forename: Robert M
authors.initials: RM
authors.lastname: Freedom
authors.forename: Lee N
authors.initials: LN
authors.lastname: Benson
mesh_terms: D001705:Bioprosthesis; D002648:Child; D003251:Constriction, Pathologic / Q000628:therapy; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D011664:Pulmonary Valve; D015607:Stents