Redo Transcatheter Aortic Valve Implantation with the ALLEGRA Transcatheter Heart Valve: Insights from Bench Testing

Failure of transcatheter heart valves (THV) may potentially be treated with repeat transcatheter aortic valve implantation (redo TAVI). We assessed hydrodynamic performance, stability and pinwheeling utilizing the ALLEGRA (New Valve Technology, Hechingen, Germany) THV, a CE approved and marketed THV in Europe, inside different THVs.

Redo TAVI was simulated with the 27 mm ALLEGRA THV at three implantation depths (-4 mm, 0 mm and +4 mm) in seven different 'failed' THVs: 26 mm Evolut Pro, 25 mm Lotus, 25 mm JenaValve, 25 mm Portico, 23 mm Sapien 3, 27 mm ALLEGRA and M ACURATE neo. Hydrodynamic evaluation was performed according to International Standards Organization 5840-3:2021.

The ALLEGRA THV was stable with acceptable performance (gradient <20 mmHg, effective orifice area >2 cm², and regurgitant fraction <20%) in all 'failed' THVs except the Evolut Pro at -4 mm implantation depth. In this configuration, the outflow of the ALLEGRA frame was constrained by the Evolut Pro THV and the ALLEGRA leaflets were unable to fully close. Pinwheeling was severe for the ALLEGRA in Evolut Pro. The neo-skirt was higher with taller frame THVs.

The ALLEGRA THV had favorable hydrodynamic performance, stability and pinwheeling in all redo TAVI samples except the Evolut Pro at low implantation depth with compromised function. The choice of initial THV may have late implications on new THV choice and function.