Transcript Slide 1
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 – 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 7075o • 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 Medtronic Freestyle Stentless Valve St. Jude Toronto SPV Ross flexible homograft support Common sites of origin of extravalvular spread