Experimental Study of Bileaflet Mechanical Heart Valves

Biological or mechanical heart valve prostheses are used as a treatment to replace failing native heart valves. The goal of this study is to investigate the hydrodynamic performance of small sizes bileaflet mechanical heart valves (BMHVs) considering their use to control flow direction on a pulsatile pediatric ventricular assist device (VAD) [1]. Small size BMHVs of 17, 19 mm were tested in vitro and compared to 23 mm prosthesis. Each prosthesis was placed on a pulse duplicator (4–90 bpm, 2.0–4.0 L/min flow range) and pressure and flow signals were recorded to determine pressure gradient, flow regurgitation and effective orifice area (EOA). Pressure gradients (maximum/minimum; mmHg) were (12.2/8.5), (8.4/6.3) and (8.2/5.8), for 17, 19 and 23-mm, respectively. Valve effective orifice areas (maximum/minimum; cm²) were (1.05/1.02), (1.37/1.24) and (1.55/1.35) for 17, 19 and 23-mm sizes, respectively. The regurgitation fractions (maximum/minimum; %) obtained were (6.91/5.29), (10.47/6.08), and (14.63/10.04), for 17, 19 and 23-mm sizes, respectively. The results suggest that the mechanical valves have adequate performance according to the requirements of the ISO 5840:2015 standards and that they can be used to effectively control flow direction on a pediatric pulsatile ventricular assist device.