Trans-catheter valve-in-valve implantation: in vitro hydrodynamic performance of the SAPIEN+cloth trans-catheter heart valve in the Carpentier-Edwards Perimount valves.

OBJECTIVE: Since 1990, over 1.2 million bioprosthetic valves were implanted for aortic stenosis. Given the risk of structural valve deterioration, the need to redo AVR will likely rise. Recently, SAPIEN valve-in-valve (ViV) has been advocated. We evaluated the in vitro hydrodynamic performance of the Edwards SAPIEN+cloth trans-catheter heart valve (THV) implanted within the Carpentier-Edwards Perimount (CEP) valve. METHODS: Both 23- and 26-mm Edwards SAPIEN+cloth THVs (Model 9000MIS) were deployed within 23- or 25-mm (1) CEP aortic bioprosthesis (Models 2700 and 2800), (2) CEP Magna (Model 3000), and (3) CEP plus pericardial mitral (Model 6900P), respectively. Tests included: (1) mean pressure gradient; (2) pulsatile effective orifice area (EOA); (3) regurgitant volume; (d) migration during accelerated wear testing (AWT; 20 million cycles @ 200mmHg); and (5) valve dislodgement pressure. Values tested per ISO 5840:2005 valve standards; mean±SD. RESULTS: Post-deployment pressure gradient across the combined valves ranges from 2.8±0.3 to 8.7±0.5mmHg. The post-deployment EOA of the valves ranged from 1.7±0.1 to 2.0±0.0cm(2). Pulsatile flow regurgitant volume ranged from 2.1±0.7 to 7.6±1.2ml. Migration during the AWT ranged from 0.01±0.27 to 1.61±0.92mm. Pressure increase during the tests to quantify migration ranged from >400 to >800mmHg. CONCLUSIONS: Compared with the rigorous ISO 5840:2500 valve standards, the Edwards SAPIEN+cloth THV implanted ViV within the CEP valve demonstrated excellent hydrodynamic performance.

Evolution and future of preclinical testing for endovascular grafts.

The preclinical testing of endovascular grafts has evolved significantly since the creation and early testing of these devices; however, there are continued limitations in using preclinical testing to predict clinical performance. Early testing was conducted in the absence of standards and guidance specific to endovascular grafts, and references available for vascular grafts and stents did not adequately account for the complexity of endovascular graft systems. Failure of early-generation devices suggested that the testing being conducted was inadequate and that there was a lack of understanding of the in vivo environment. These concerns led to several efforts to improve preclinical testing. The Food and Drug Administration (FDA) sponsored a workshop to discuss the limitations inherent in testing of endovascular grafts, and an ISO standard for endovascular grafts was developed. Publication of the standard in 2003 succeeded in standardizing testing and reporting across device manufacturers; however, several clinical failure modes, such as migration and stent fractures, continued to be unpredicted by current preclinical testing. This, coupled with knowledge gained from additional clinical experience, led the FDA to hold a second workshop to discuss the benefits and limitations of current testing and propose future testing that may better predict device performance. This workshop was successful in accurately describing past testing, determining what has been learned, identifying issues that have not been adequately addressed, proposing modifications to address these limitations, and discussing how the proposed modifications should be implemented. While significant progress has been made in endovascular graft testing, continued collaboration among industry, academia, regulators, and clinicians will provide continued improvement in the predictability of device performance.