Energy loss due to paravalvular leak with transcatheter aortic valve implantation.

BACKGROUND: Mild to moderate paravalvular leaks commonly occur after transcatheter aortic valve (TAV) implantation. Current TAVs match and may exceed hemodynamic performance of surgically implanted bioprostheses based on pressure gradient and effective orifice area. However, these hemodynamic criteria do not account for paravalvular leaks. We recently demonstrated that TAV implantation within 23 mm Perimount bioprostheses (Edwards Lifesciences, Irvine, CA) yields similar hemodynamics to the 23 mm Perimount valve. However, mild paravalvular leakage was seen after TAV implantation. The present study quantifies energy loss during the entire cardiac cycle to assess the impact of TAV paravalvular leaks on the ventricle.

METHODS: Four TAVs designed to mimic the 23 mm SAPIEN valve (Edwards Lifesciences) were created. Transvalvular energy loss of 19, 21, and 23 mm Carpentier-Edwards bioprostheses were obtained in vitro within a pulse duplicator as a hemodynamic baseline (n = 4). The 23 mm TAVs were subsequently implanted within the 23 mm bioprostheses to assess energy loss due to paravalvular leak.

RESULTS: The 23 mm bioprosthesis demonstrated the least energy loss (213.25 +/- 31.35 mJ) compared with the 19 mm (330.00 +/- 36.97 mJ, p = 0.003) and 21 mm bioprostheses (298.00 +/- 37.25 mJ, p = 0.008). The TAV controls had similar energy loss (241.00 +/- 30.55 mJ, p = 0.17) as the 23 mm bioprostheses. However, after TAV implantation, total energy loss increased to 365.33 +/- 8.02 mJ significantly exceeding the energy loss of the 23 mm bioprosthesis (p < 0.001). Due to mild TAV paravalvular leakage, 39% of energy loss occurred during diastole.

CONCLUSIONS: Substantial energy loss during diastole occurs due to TAV paravalvular leakage. In the presence of mild paravalvular leakage, TAV implantation imposes a significantly higher workload on the left ventricle than an equivalently sized surgically implanted bioprosthesis.