Valve-in-valve hemodynamics of 20-mm transcatheter aortic valves in small bioprostheses.

BACKGROUND: Transcatheter aortic valve (TAV) implantation is a treatment for selected patients with failing bioprostheses. We previously showed that currently available SAPIEN (Edwards Lifesciences, Irvine, CA) TAV sizes did not yield acceptable valve-in-valve (VIV) hemodynamics in small degenerated bioprostheses because optimal TAV function requires full stent expansion to its nominal size. The study objective was to determine (1) if 20-mm TAVs provide acceptable hemodynamics in small degenerated bioprostheses and (2) the effect of TAV spatial orientation on valvular hemodynamics and coronary flows.

METHODS: Twelve 20-mm TAVs were created for implantation within 19-mm and 21-mm degenerated Carpentier-Edwards Perimount (Edwards Lifesciences) and porcine bioprostheses. Degenerated valves were sutured into human homograft roots and mounted in a pulse duplicator. TAVs were implanted within bioprostheses as VIV in standard orientation, in which TAV and bioprosthetic commissures were aligned, and later with 60-degree rotation.

RESULTS: The 20-mm TAVs migrated retrograde into the left ventricle after VIV in the 21-mm Perimount bioprostheses. However, 20-mm TAVs in 19-mm Perimount (54.9±5.4 to 23.5±3.9 mm Hg, p=0.006) and 21-mm porcine bioprostheses (35.2±8.9 to 16.8±4.1 mm Hg, p=0.03) significantly reduced mean gradients. No significant reduction in pressure gradient occurred after VIV in 19-mm degenerated porcine bioprostheses. Mild regurgitation was observed after VIV. VIV with standard and 60-degree TAV orientation did not significantly alter hemodynamics or coronary flows.

CONCLUSIONS: Valve-in-valve hemodynamics with 20-mm TAV improved for 19-mm Perimount and 21-mm porcine but not 19-mm porcine bioprostheses. No significant differences in hemodynamics were noted by orientation with TAV and bioprosthesis commissural alignment or 60-degree rotation.