Impact of implant depth on hydrodynamic function of the ALLEGRA bioprosthesis in valve-in-valve interventions

Aims: We aimed to assess the impact of implant depth on hydrodynamic function following valve-in-valve (VIV) intervention using the ALLEGRA transcatheter heart valve (THV) in three different surgical valve designs. Methods and results: Multiple implantation depths (+2 mm, -2 mm and -6 mm) were tested using a 23 mm ALLEGRA THV for VIV intervention in 19 mm, 21 mm, 23 mm, and 25 mm Epic, Mitroflow and Magna Ease bioprosthetic valves. Multimodality imaging and hydrodynamic evaluation was performed at each implantation depth. The 23 mm ALLEGRA valve had gradients <20 mmHg in the Mitroflow and Epic valves sized ≥21 mm, and in all sizes of the Magna Ease valve. Gradients did not increase significantly at lower implantation depths. The 19 mm Epic (+2 mm: 20.1±0.6 mmHg, -2 mm: 18.8±0.5 mmHg, -6 mm: 22.8±0.3 mmHg) and 19 mm Mitroflow (+2 mm: 24.1±0.2 mmHg, -2 mm: 31.5±0.3 mmHg, -6 mm: 25.6±0.2 mmHg) valves had elevated mean gradients. In larger sized surgical valves (≥23 mm) the regurgitant fraction was higher at low implantation depths. Pinwheeling was significantly worse in the smaller sized (≤21 mm) surgical valves and also at low (<-2 mm) implantation depth. Conclusions: The 23 mm ALLEGRA valve had favourable (<20 mmHg) gradients in all surgical valves sized ≥21 mm, even when the THV was implanted low. In 19 mm sized Mitroflow and Epic valves, gradients were elevated (>20 mmHg). While there was no major difference in mean transvalvular gradients, leaflet pinwheeling was worse at lower implantation depths.