title: Does large oversizing of self-expandable endoprostheses compensate for aortic growth?
abstract: OBJECTIVE
  There is experimental evidence that self-expandable endoprostheses are appropriate for compensation of aortic growth. A potential future application includes their use in the treatment of aortic coarctation. Yet their behavior is poorly investigated. The present study evaluates the performance of largely oversized self-expandable endoprostheses (EPs) in the growing porcine aorta and the biologic response toward them.
  
  
  METHODS
  Twenty oversized EPs (Talent, TalentLoPro, Stenway, and Wallstent; nominal lumen area 314 mm(2) [diameter 20 mm]) were implanted in the descending thoracic aorta of juvenile pigs. Four nonoversized EPs (TalentLoPro; nominal lumen area 154 mm(2) [diameter 14 mm]) served as controls. Cross sections of aorta and EPs were measured by intravascular ultrasound (IVUS) at implantation and 3 months follow-up. The histologic response was assessed by microscopy.
  
  
  RESULTS
  At implantation, the EPs were 99 +/- 41% oversized relative to the aortic area [48 +/- 22% in diameter]. At follow-up, the area of the aortic lumen increased 60 +/- 50%, P <.001 [29 +/- 23% in diameter]. The Stenway EPs demonstrated the largest prosthetic lumen with 80 +/- 10% of their nominal area (P =.001). However, the prosthetic lumen area was reduced by intimal hyperplasia in all devices. The largest perfused lumen was obtained by the TalentLoPro EPs due to their progressive expansion. Nonoversized EPs resulted in a significantly smaller perfused lumen (P =.012). The inflammatory response to polyester was moderate, whereas polyurethane evoked an extensive body-foreign reaction.
  
  
  CONCLUSIONS
  Large oversizing of self-expandable EPs is essential in order to maintain a large perfused lumen during aortic growth, thereby minimizing the adverse effect of intimal hyperplasia. This was best achieved by the TalentLoPro EPs.
authors.affiliation: Department of Cardiovascular Surgery, University Hospital, Rue du Bugnon 46, 1011 Lausanne, Switzerland. Bettina.Marty@chuv.hospvd.ch
authors.forename: Bettina
authors.initials: B
authors.lastname: Marty
authors.forename: Bernard
authors.initials: B
authors.lastname: Maeder
authors.forename: Augusto
authors.initials: A
authors.lastname: Gallino
authors.forename: Antonio
authors.initials: A
authors.lastname: Mucciolo
authors.forename: Ludwig Karl
authors.initials: LK
authors.lastname: von Segesser
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000254:growth & development* / Q000473:pathology / Q000601:surgery; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D019917:Blood Vessel Prosthesis Implantation; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000254:growth & development* / Q000473:pathology / Q000601:surgery; D006965:Hyperplasia / Q000209:etiology / Q000473:pathology; D011474:Prosthesis Design; D013552:Swine