In vitro coronary flow after transcatheter aortic valve-in-valve implantation: A comparison of 2 valves.

Background: Transcatheter aortic valve-in-valve implantation (TAVI-ViV) is an evolving treatment strategy for degenerated surgical aortic valve bioprostheses (SAVBs). However, there is some concern regarding coronary obstruction, especially after TAVI-ViV in calcified SAVBs with externally mounted leaflets. We investigated in vitro coronary flow and hydrodynamics after TAVI-ViV using 2 modern SAVBs with externally and internally mounted leaflets.

Methods: Aortic root models including known risk factors for coronary obstruction served for the implantation of SAVBs with either externally mounted leaflets (St Jude Trifecta, size 25) or internally mounted leaflets (Edwards Perimount Magna Ease, size 25). Left and right coronary flow, as well as hydrodynamic parameters, were measured before and after TAVI-ViV with an Edwards Sapien XT transcatheter heart valve, size 23. After the first experimental run, the SAVB leaflets were artificially "calcified," and the measurements were repeated.

Results: In both models, noncalcified and calcified, there was no significant reduction in coronary flow with either the Trifecta or the Perimount Magna Ease SAVB. After TAVI-ViV, in the noncalcified model, the mean pressure gradient was increased (Trifecta, P = .0001; Perimount Magna Ease, P = .006) and the geometric orifice area was decreased (P < .001 for both), whereas in the calcified model, the mean pressure gradient was decreased (P < .001 for both) and the geometric orifice area was increased (P < .001 for both).

Conclusions: In our specific model, in noncalcified as well as calcified conditions, TAVI-ViV is feasible with either SAVB (Trifecta or Perimount Magna Ease) without an increased risk of coronary obstruction. Nevertheless, before clinical application of these results, thorough preoperative assessment, considering the different limitations of this model, is mandatory.