Valve in valve transcatheter aortic valve implantation (ViV-TAVI) is an alternative to redo surgical aortic valve replacement (SAVR) in inoperable patients and inpatients at high operative risk. This has become even more important now that approximately 80% of all SAVR are bioprostheses and bioprostheses are implanted at younger age. Several TAVI valves have received CE mark and premarket approval for use in degenerated bioprosthesis. This study analysed the effects of design of four different surgical bioprostheses on the hydrodynamic function of an Edwards Sapien XT valve implanted as a ViV-TAVI.
Main findings of this study were:
Although there was complete coaptation of the leaflets in all 23-mm label-size ViV combinations, there were considerable differences in regurgitation measurements. This means the differences are attributable to paravalvular leakage. The Sapien XT in the Trifecta and the Perimount had the largest paravalvular leakage compared to the Aspire and Mosaic valves.
The paravalvular leakages are most likely the result of different valve material as the porcine leaflets of the Aspire and the Mosaic are less stiff and provide better seal.
Surgical valves with externally mounted leaflets (Trifecta) have an increased risk of paravalvular leakage in the ViV combination.
On the other hand, mean pressure gradient (MPG) was lower in valves with a higher surgical inner diameter (the Perimount and Trifecta valves).
Higher MPG was the result of underexpansion of the Sapien XT in the Trifecta and Mosaic valves, leading to axial overlap of the leaflets.
In conclusion:
This study showed that surgical valves with a large valve area improved hemodynamics for future ViV-TAVI combinations. Moreover, internally mounted leaflets seem to decrease the risk of paravalvular leakage.
Although this is an interesting study, this bench test study was limited to 23mm surgical valves and no calcifications or pannus of the surgical valves were simulated. Use of the valve-in-valve app developed by Dr. Bapat, remains helpful for clinicians making decisions on which TAVI valve is recommended in a specific surgical valve (https://itunes.apple.com/nl/app/valve-in-valve/id655683780?mt=8)
