Bjork-Shiley (Tilting disc) 29 mm
Peak gradient:	7.83 ± 2.93 mmHg
Mean gradient:	2.83 ± 1.27 mmHg
Peak velocity:	1.37 ± 0.25 m/s
Pressure half-time:	79 ± 17 ms
Effective orifice area:	2.1 ± 0.43 cm2