Advantages and Disadvantages of Heart Valve Prostheses With Flexible Supporting Frame Compared With the Classic Stented Prostheses: Evaluation of the Hydrodynamic Indicators of the “Uniline” and “Tiara” Bioprostheses

Highlights The «TiAra» bioprosthetic heart valves have better hemodynamic characteristics, such as higher effective orifice area and a lower mean pressure gradient. The «UniLine» bioprosthetic heart valve demonstrated better closing dynamic, expressed in a smaller regurgitation volume. Aim. To assess hydrodynamic characteristics of the «TiAra» bioprosthetic heart valve with flexible supporting frame compared with the classic stented «UniLine» bioprosthetic aortic valve. Methods. Using the Vivitro Pulse Duplicator (Vivitro Labs, Canada), we simulated the function of the heart via generating pulsatile flow to analyze bioprosthetic heart valves. To comprehensively assess the bioprosthesis function, three valves of each standard size (21, 23, 25 mm) were submitted to hydrodynamic testing, thus making a sample of nine bioprostheses of each model. The article provides the analysis of the effective orifice area, mean pressure gradient, regurgitation volume, and assessment of the statistical sensitivity of the parameters between groups at p = 0.05. Results. The assessment revealed that the «TiAra» bioprosthesis has bigger effective orifice area (p = 0.006) and lower mean pressure gradient (p = 0.02): 1.6–2.2 cm2 and 3.6–6.3 mmHg versus 1.08–1.73 cm2 and 4.8–12.1 mmHg, respectively. The regurgitation volume, however, was lower in the «UniLine» bioprostheses 0.8–4.1 mL/cycle versus 6.2–9.0 mL/cycle (p = 0.0004). Conclusion. Despite the fact that both studied models showed good hydrodynamic performance, the prosthesis with the flexible supporting frame («TiAra») showed better results regarding its effectiveness in vitro via presenting with bigger effective orifice area and lower mean pressure gradient. At the same time, the «UniLine» stented bioprosthesis had lower regurgitation volume, i.e. better closing dynamics.