Table 6:

Polymeric heart valve geometries – description and testing results.

Year	Author(s)	Geometry/description	Results	References
Bileaflet valves
1959	Braunwald & Morrow, Boston	Shape based on plaster casts of human and animal mitral valves	In vivo – Human implant (mitral), 60 hours and 4 months (1st human PU valve	[196], [237]
2003	Iwasaki et al., Waseda	Valves for pulsatile pumps Type A – Circular flexible disc attached to a frame along the diameter, producing two flaps. Type B – 12-spoke structure cast from polyurethane with a 150 μm disc on top	In vitro – Type A: 8.8 × 105 cycles Type B – 3.7 x106 cycles	[238]
2006	Daebritz et al., Munich	Kidney shaped stent with two asymmetrical struts supporting a large anterior and smaller posterior leaflet	In vitro – 1 billion (109) cycles	[42], [197], [213]
Trileaflet valves
1958, 1966	Roe et al., San Francisco	Conical cusps, shown to be less resistant to opening than dome-shaped cusps	In vitro - 786 million cycles In vivo – 18 clinical human implants, 4 post-operative survivors from 79-100 months	[200]–[202], [239]
1977	Reul & Ghista, HIA	Analytical determination of shapes for smooth washout, minimum leaflet stress and fatigue lifetime of 20 years	In vitro – 350+ million cycles	[163], [193]
1982	Wisman et al., Penn State	3 hemicylindrical leaflets of 10 mm diameter each angled with respect to the flow axis, with flexible support framework	In vitro – good hydraulic function and efficiency In vivo – calcification and thrombosis in growing calf, longer survival and less calcification in mature animals	[204]
1994	Fisher et al., Leeds	Variable radius of curvature where the radius of curvature of leaflet increases away from the center of the valve towards the base of the leaflet	In vitro – 180 μm leaflets produced a pressure drop of less than 1 mmHg	[161]
1996	Wheatley et al., Glasgow	Leaflet geometry is elliptical radially and continuous hyperbolae circumferentially	In vitro – 800 million cycles In vivo – 6-month survival in sheep	[37], [38], [240]
2004	Jiang et al., Ontario	Hyperboloids of revolution: control of central opening and leaflet curvature by varying parameters such as coaptation at commissures and curvature of free edge	In vitro – successful demonstration of opening/closing of valve using a cyclic flow tester	[205]
2009	Mohammadi et al., Ontario	Bezier curves/surfaces	FEA showed acceptable opening/closing characteristics and good stress distribution	[176]
2009	Bluestein et al., Stony Brook	Hemispherical geometry, originating from Thubrikar’s characterization, leaflet thickness varying along the radial direction	FEA and fluid dynamic simulations showed superior stress distribution and improved hemodynamics	[44], [165]
2010	Burriesci et al., UCL	Ruled surface between intersection of the stent cylinder with a plane and an arc joining the commissures, lying on a plane normal to the valve axis.	In vitro – 10 cycles testing – less energy loss, blood trauma and clot formation	[47], [185], [188], [199]
2015	Gharaie & Morsi, Victoria	Sweeping a circumferential curve along a radial curve	FSI model showed improved characteristics compared to other polymeric valves, with EOA of 3.22 cm2 and pressure drop of 3.52 mmHg	[209]