Case Example and Bench Testing of Hydrodynamic Performance and Migration Stability of Various Valve-in-Valve...

Valve-in-valve (ViV) implantation offers a less invasive treatment for degenerated bioprostheses. However, experience with ViV implantation in large self-expanding pulmonary valves is limited, and optimal sizing and stability remain uncertain. A young woman with Noonan syndrome and severe lymphatic disorder underwent implantation of a 36-25 mm VenusP-valve (Venus Medtech) for severe pulmonary regurgitation. Six years later, the valve showed a mild gradient increase and moderate regurgitation (cardiac magnetic resonance regurgitation fraction of 30%). Given her severe lymphatic disorder, repeat percutaneous valve implantation was performed. A second 36-25 mm VenusP-valve was implanted within the existing valve. Incomplete frame apposition was improved with balloon dilation. At 2-year follow-up, there was no systolic gradient and only trace pulmonary regurgitation. Multiple ViV configurations were evaluated in a pulsatile flow system, including one-size-smaller VenusP-valves, a balloon expandable valve, and modified self-expanding valves with flares removed. Effective orifice area (EOA) and regurgitation fraction (RF), including central and paravalvular leakage, were assessed. All configurations showed complete inner-frame expansion and unrestricted leaflet motion, with EOA exceeding predefined acceptance thresholds and RF remaining in the single-digit range. No migration occurred with inner valves one to two sizes smaller than the outer valve under standard conditions, whereas substantially undersized configurations demonstrated instability at higher pressures. ViV implantation within a large self-expanding VenusP-valve was feasible, with favorable function at 2 years. Bench testing demonstrated favorable hydrodynamic performance and supported the stability of appropriately sized inner valves. Further preclinical and clinical evaluation is warranted.