title: Quality control of bioprosthetic heart valves by means of holographic interferometry.
abstract: OBJECTIVE
  Limited durability of porcine bioprostheses is mainly caused by the progressive development of calcification. We tested the hypothesis that hidden tissue anomalies or unfavorable stress concentrations of commercially available bioprostheses may lead to later calcification and dysfunction. Application of holographic interferometry for non-destructive testing of biological heart valves enables a full-field analysis of heart valves and reveals deformation irregularities of valve tissue.
  
  
  METHODS
  We developed an accelerated calcification protocol for bioprosthetic heart valves including an accelerated pulsatile valve tester for simultaneous testing of 10 heart valves under identical conditions and a rapid synthetic calcification fluid containing a final Ca x P of 130 (mg/dl)2 in barbital buffer solution. Ten porcine bioprostheses (St. Jude Medical, Bioimplant) were assessed by holographic interferometry and subjected to the pulsatile accelerated calcification process. Distribution and amount of calcification was evaluated by microradiography after 12 x 10(6) and 19 x 10(6) cycles, respectively. Areas of irregular fringe patterns detected by holography as well as areas of calcification were calculated and compared using a personal computer.
  
  
  RESULTS
  All tested bioprostheses had localized or extended areas with holographic irregularities and the accelerated valve testing protocol resulted in even macroscopically visible calcifications at various sites. Comparative analysis of the obtained microradiographs revealed that 74.2% +/- 6.0% of calcified leaflet areas lay within the previously detected holographic anomalies.
  
  
  CONCLUSIONS
  Our first results show a strong correlation between holographic anomalies and calcification of porcine bioprostheses. We conclude that suitable methods for evaluation and quality control of bioprosthetic heart valves are available and seem to be predictive with regard to valve calcification.
authors.affiliation: Department of Cardiothoracic & Vascular Surgery, WWU Münster, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Deiwick
authors.forename: B
authors.initials: B
authors.lastname: Glasmacher
authors.forename: A M
authors.initials: AM
authors.lastname: Zarubin
authors.forename: H
authors.initials: H
authors.lastname: Reul
authors.forename: A
authors.initials: A
authors.lastname: Geiger
authors.forename: G
authors.initials: G
authors.lastname: von Bally
authors.forename: A
authors.initials: A
authors.lastname: Stargardt
authors.forename: G
authors.initials: G
authors.lastname: Rau
authors.forename: H H
authors.initials: HH
authors.lastname: Scheld
mesh_terms: D001021:Aortic Valve; D001705:Bioprosthesis / Q000592:standards*; D002114:Calcinosis; D006350:Heart Valve Prosthesis / Q000592:standards*; D006696:Holography; D006801:Humans; D007368:Interferometry; D008027:Light; D008852:Microradiography; D008943:Mitral Valve; D011785:Quality Assurance, Health Care