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.