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Aortic Valves. Bileaflet Prosthesis. Lowest gradient due to wide opening angle Minimal turbulence due to Wide opening angle Thin leaflets Large cross-sectional area. Tilting Disc Prosthesis. Less obstruction to blood flow Gradients of 6-7 mmHg Opening angle
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Bileaflet Prosthesis • Lowest gradient due to wide opening angle • Minimal turbulence due to • Wide opening angle • Thin leaflets • Large cross-sectional area
Tilting Disc Prosthesis • Less obstruction to blood flow • Gradients of 6-7 mmHg • Opening angle • High; low gradients, increased regurgitation • Small; High gradients; less regurgitation
Ball Valve • Minimal leakage • Annular area for flow creates turbulence • High profile may occlude VOT • Cage may contact ventricular wall during contraction • Partial obstruction by the ball in aortic position
Medtronic Hall Prosthesis • Monoleaflet • Central guide for leaflet travel • Housing and central guide made of titanium • Opening angle of 70-75o • Leaflet motion is by translation and rotation
Sorin Allcarbon Monoleaflet • Chromium alloy housing coated with a thin film of carbon • Pyrolytic carbon monoleaflet • Strut mechanism integral with housing • Sewing ring carbon coated
Bjork-Shiley Monostrut • Monoleaflet prosthesis • Orifice ring and integral struts are constructed from a single piece of cobalt-chromium alloy • Opening angle of 70o • Relatively low velocity retrograde washing between leaflet and orifice • Leaflet motion is by rotation and translation
ATS Medical • Pyrolyte housing and pyrolite carbon leaflets with graphite substrate • Convex housing with protrusions on the inner aspect that support the leaflets therefore no protruding struts • Convex hinge mechanism facilitate retrograde washing • Opening angle of 85o
Biocarbon Prosthesis • Sorin Biomedica • Titanium housing covered by pyrolite carbon strengthens prosthesis • Curved leaflets • Two effluent passages provide continuous washing even in the closed position • Orifice divided into three sections • Sewing ring dacron and carbon coated teflon • Hinge mechanism supports a rolling motion
Edwards MIRA Prosthesis • Bileaflet prosthesis • Pyrolite coated leaflets over tungsten impregnated carbon • Curved leaflets enhance central flow and leaflet closure • Retrograde washing by relative high frequency jets • Closes by rotation and translation
Carbomedics Prosthesis • Solid pyrolite housing • Pyrolite coated leaflets over tungsten impregnated carbon • Radiopaque titanium stiffened ring • Opening angle of 78o • Leaflets can be rotated in the orifice
St Jude Medical • Pyrolytic carbon over graphite substrate for housing and leaflets • Leaflets impregnated with tungsten for radiopacity • Leaflets open to 85o resulting in near central laminar flow • 10% regurgitant flow • Leaflet motion by rotation
Comparison between orifice area in stented and stentless valves Stentless Stented