HYDRODYNAMIC ASSESSMENT OF NEW POLYMERIC HEART VALVES UNDER CONTINUOUS AND PULSATILE FLOW

Aim: In order to combine the hemodynamic properties of biological valves with the durability of mechanical valves a new prosthetic heart valve (PHV) made of styrenic block co-polymers was developed. Aim of this work was to evalu- ate the haemodynamic performances (regurgitation and pressure drop) of the developed PHV. Methods: Two groups each one comprising 8 PHVs prototypes differing in poly- styrene fraction (19% and 30%) were tested under continuous and pulsatile flow conditions. The continuous tests were carried out at flow rates from 0 to 10 l/min (step 0.5 l/min) to evaluate pressure drops. Static regurgitation was assessed by applying backpressures from 30 to 130 mmHg. A test bench was specifically built according to the ISO5840 guidelines. Each valve was tested at different cardiac output, frequency and backpressure. Regurgitation, pressure drops and effective orifice area (EOA) were evaluated. Unpaired t-Test was used to evalu- ate the statistical difference (p<0.01) between the two groups. Results: All 16 PHVs met the minimum requirements of ISO5840. The PHVs made up of 30% polystyrene showed higher pressure drops than the other group under both pulsatile and steady flow conditions, while no statistical differ- ences was present in static and dynamic regurgitation between the two groups in both tests. Conclusions: The results of this study demonstrate the effectiveness of the newly developed PHVs, encouraging further improvements to minimise regurgi- tation and maximise EOA.