1981 Volume 10 Issue 2 Pages 606-609
In this study, a new type of fan-shaped trileaflet prosthetic valve was designed, constructed and tested under the steady flow as well as the pulsatile flow conditions in a mock circulation system. The new valve is composed of an orifice ring, three semicircular leaflets, three supporting pivots and an annular cuff. Annulus diameter and orifice diameter of the valve are 30mmφ and 24mmφ respectively. Hydrodynamic evaluation was carried out on the following terms; a) flow rate v. s. pressure gradient characteristic, b) leakage flow at 100cmH2O, c) performance index at the steady flow, d) systolic energy loss, e) diastolic energy loss and f) performance index at the pulsatile flow. These characteristics were compared with those of Bjork-Shiley valve (29mmφ annulus diameter) and Starr-Edwards ball valve (30mmφ annulus diameter). Results of the steady flow (Q) v. s. transvalvularn pressure gradient (ΔP) for the tested valves were represented by the relationship of ΔP=kQ and n was almost 2. Coefficient k corresponding to the flow resistance was 0.014mmHg. (min/L)2 for the new valve, but were 0.008 for B-S valve and 0.024 for S-E valve. The forward performances (pressure gradient, systolic energy loss and performance index) of the developed valve show the fairly good characteristics among the valves tested, but relatively much leakage flow can be observed, which results in the more diastolic energy loss. Improvement of the valve, especially on the close contact of the leaflets, will give the acceptance of the in-vivo application and clinical use.
