title: Feasibility and Safety of Unzipping Small Diameter Stents in the Blood Vessels of Piglets.
abstract: This study sought to determine the feasibility and safety of unzipping small-diameter stents (SDS) in a growing animal model.
  
  
  
  SDS implanted to relieve stenosis of blood vessels in infants may result in refractory stenosis as the child grows. If stents can be longitudinally fractured-unzipped-then the target vessel can potentially be redilated to the eventual adult vessel diameter.
  
  
  
  Fifty stents (diameter 4 to 7 mm) were implanted in 5 neonatal piglets (mean age and weight = 1.5 weeks and 3.4 kg). Pre-mounted coronary (CS) (n = 24), biliary (BS) (n = 14), nitinol (NS) (n = 3), and renal stents (RS) (n = 9) were implanted in pulmonary arteries (n = 13), systemic arteries (n = 25), and systemic veins (n = 12). Three months later (median weight = 32 kg), unzipping was attempted by dilating the stents.
  
  
  
  All CS and RS unzipped at twice their nominal diameter with <20% shortening. None of the NS unzipped. The BS shortened the most (∼40%), with only 69% of the stents unzipping. Stainless steel CS and RS with an open cell design were significant predictors (p ≤ 0.01) for unzipping. On histopathology, unzipping of the BS caused the most medial dissection and vessel wall injury, while unzipping of the CS caused the least.
  
  
  
  Unzipping of small-diameter CS and RS implanted in systemic and pulmonary vessels is more feasible than the BS and NS. This study may encourage the implantation of small stents in infant blood vessels and aid in selection of appropriate stent type.
authors.affiliation: Department of Pediatrics, Division of Pediatric Cardiology, University of Tennessee Health Science Center, Memphis, Tennessee. Electronic address: shyam@uthsc.edu.
authors.forename: Shyam K
authors.initials: SK
authors.lastname: Sathanandam
authors.affiliation: Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: T K Susheel
authors.initials: TK
authors.lastname: Kumar
authors.affiliation: Department of Pathology, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Deepthi
authors.initials: D
authors.lastname: Hoskoppal
authors.affiliation: Department of Pediatrics, Division of Pediatric Cardiology, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Haddad
authors.affiliation: Department of Pediatrics, Division of Pediatric Cardiology, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Saradha
authors.initials: S
authors.lastname: Subramanian
authors.affiliation: Department of Veterinary Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Sullivan
authors.affiliation: Department of Biostatistics, Harvard Medical School, Boston, Massachusetts.
authors.forename: David
authors.initials: D
authors.lastname: Zurakowski
authors.affiliation: Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Christopher
authors.initials: C
authors.lastname: Knott-Craig
authors.affiliation: Department of Pediatrics, Division of Pediatric Cardiology, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: B Rush
authors.initials: BR
authors.lastname: Waller
mesh_terms: D000497:Alloys; D000818:Animals; D000831:Animals, Newborn; D001706:Biopsy; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D005240:Feasibility Studies; D023421:Models, Animal; D010690:Phlebography; D011474:Prosthesis Design; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000254:growth & development / Q000473:pathology; D012307:Risk Factors; D013193:Stainless Steel; D015607:Stents; D034421:Sus scrofa; D013997:Time Factors; D014680:Veins / Q000000981:diagnostic imaging / Q000254:growth & development / Q000473:pathology
chemical_list: D000497:Alloys; D013193:Stainless Steel; C013616:nitinol
keywords: fracture; stent; unzip