title: Current balloon-expandable transcatheter heart valve and delivery systems.
abstract: OBJECTIVE
  Transcatheter valve and valve delivery systems are undergoing rapid evolution. We describe the current generation balloon-expandable valve and delivery systems.
  
  
  METHODS
  The SAPIEN XT valve represents the newest generation balloon-expandable aortic bioprosthesis. A cobalt-chromium alloy frame and additional design modifications facilitate a reduction in delivery profile while maintaining structural integrity, hemodynamics, and durability. The RetroFlex 3 delivery system represents the latest clinically available delivery system. It incorporates a fixed, tapered, and deflecting crossing tip to facilitate atraumatic introduction and a rapid inflation lumen to reduce valve motion during deployment. The NovaFlex delivery system represents the next generation delivery catheter. When used in conjunction with the SAPIEN XT valve and a specially constructed introducer sheath the inner and the outer diameters are 18 and 21 F, respectively.
  
  
  RESULTS
  The RetroFlex 3 delivery system was utilized in nine patients and the NovaFlex delivery system in four. The valve implanted was the SAPIEN in six and the SAPIEN XT valve in seven. Implantation was successful in all patients. A reduction in device movement during balloon deployment was apparent as compared with earlier delivery systems. Aortic mean gradient fell from 45.6 (+/-15.1) mm Hg to 13.2 (+/-5.1) mm Hg, valve area rose from 0.68 (+/-0.19) to 1.5 (+/-0.28) cm(2). No patient had more than mild paravalvular regurgitation.
  
  
  CONCLUSIONS
  Transcatheter valves and delivery systems continue to improve in terms of profile and ease of use.
authors.affiliation: Department of Cardiology, St. Paul's Hospital, British Columbia, Canada.
authors.forename: Fabian
authors.initials: F
authors.lastname: Nietlispach
authors.forename: Namal
authors.initials: N
authors.lastname: Wijesinghe
authors.forename: David
authors.initials: D
authors.lastname: Wood
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Carere
authors.forename: John G
authors.initials: JG
authors.lastname: Webb
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D001705:Bioprosthesis; D002404:Catheterization / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D011859:Radiography; D012720:Severity of Illness Index; D016896:Treatment Outcome