QUALITY-CONTROL OF BIOPROSTHETIC HEART-VALVES BY MEANS OF HOLOGRAPHIC-INTERFEROMETRY

Background and aims of the study: Limited durability of porcine biopro stheses is mainly caused by the progressive development of calcificati on. We tested the hypothesis that hidden tissue anomalies or unfavorab le stress concentrations of commercially available bioprostheses may l ead 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. Material and methods: We developed an accelerated calcification protocol for bioprosthetic heart valves inc luding an accelerated pulsatile valve tester for simultaneous testing of 10 heart valves under identical conditions and a rapid synthetic ca lcification fluid containing a final Ca x P of 130 (mg/dl)(2) in barbi tal buffer solution. Ten porcine bioprostheses (St. Jude Medical, Bioi mplant(R)) were assessed by holographic interferometry and subjected t o the pulsatile accelerated calcification process. Distribution and am ount of calcification was evaluated by microradiography after 12x10(6) and 19x10(6) cycles, respectively. Areas of irregular fringe patterns detected by holography as well as areas of calcification were calcula ted and compared using a personal computer.Results: All tested biopros theses had localized or extended areas with holographic irregularities and the accelerated valve testing protocol resulted in even macroscop ically visible calcifications at various sites. Comparative analysis o f the obtained microradiographs revealed that 74.2% +/- 6.0% of calcif ied leaflet areas lay within the previously detected holographic anoma lies. 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 b ioprosthetic heart valves are available and seem to be predictive with regard to valve calcification.