Impact of progressive sinotubular junction dilatation on valve competence of the 3F Aortic and Sorin Solo stentless bioprosthetic heart valves

Objective: The use of stentless bioprostheses for aortic valve replacement provides excellent haemodynamics; however, these valves bear the potential risk of progressive regurgitation over time. To overcome this disadvantage, a new generation of pericardial stentless prostheses has been developed. This study aims to assess the tolerance of such bioprotheses against progressive sinotubular junction dilatation. Methods: Five specimens of both the 3F Aortic and Sorin Solo stentless bioprotheses (diameter 25 mm) were investigated in a pulsatile flow simulator incorporating a device for gradual expansion of the sinotubular junction diameter. Closing characteristics were obtained by high-speed video imaging and the corresponding regurgitations were determined by ultrasonic flow measurements. The diameters D_R, at which primary distinct regurgitation occurs, were correlated to the original diameters D_A and expressed as percentage values. Results: The highest tolerance against sinotubular junction dilatation was found for the 3F Aortic (156 ± 5%) compared to the Sorin Solo (145 ± 6%, p = 0.0127) bioprothesis. Visualisation of the valves revealed strong leaflet folding at labelled diameter, similar in both valve types. Conclusions: New-generation pericardial stentless bioprotheses provide favourable adaptability to sinotubular junction dilatation, more pronounced for the 3F prosthesis. Whether undue leaflet folding caused by the redundant tissue influences long-term function remains to be established.